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Parasite aggregation within hosts is a fundamental feature of parasite distributions, whereby the majority of parasites are harboured by a minority of hosts. Parasite aggregation can influence their transmission and hence control. In this narrative review, possible sources of aggregation of Taenia solium cysticerci in pigs are discussed, along with implications for control of the parasite. While heavy T. solium infections in pigs could most likely be associated with ingestion of high doses of infective parasite eggs, consistent with coprophagic behaviour of pigs, lighter infections indicate a role of indirect routes of transmission to pigs, mostly from lower infection doses. Light infections are likely to be missed by commonly used diagnostic methods - tongue examination or meat inspection - and end up in the food chain. Hence, they entail a 'hidden' risk and are of a particular public health concern, especially in areas where meat is consumed raw or undercooked. To be effective and sustainable, control strategies against T. solium likely require a broader understanding of, and consideration for parasite transmission dynamics. More importantly, a holistic One Health approach incorporating interventions on humans, pigs and the environment will likely have a larger, more successful and sustainable impact., Competing Interests: Uffe C. Braae is currently employed by Novo Nordisk A/S. There is no conflict of interest to declare for other authors, (© 2023 The Authors.)

Taenia solium diagnosis is challenging as trained personnel, good diagnostic tools, and infrastructure is lacking in resource-poor areas. This paper aims to describe the study trial design adopted to evaluate a newly developed rapid point-of-care test that simultaneously detects taeniosis and neurocysticercosis (TS POC) in three district hospitals in Tanzania. The two-stage design included three types of patients: patients with specific neurological signs and symptoms (group 1); patients with complaints compatible with intestinal worm infections (group 2); patients with other symptom(s) (group 3). For group 1, all patients were tested using the TS POC test (stage 1), after which all positive, and a subset of negative, patients were selected for laboratory reference tests, clinical examination, and a brain computed tomography (CT) scan (stage 2). For groups 2 and 3, a similar design was adopted, but clinical examination and a brain CT scan (stage 2) were only performed in patients who were TS POC test-positive for cysticercosis. Due to the lack of a gold standard, a Bayesian approach was used to determine test accuracy for taeniosis and cysticercosis. For neurocysticercosis, a composite case definition was used as the reference standard. If successful, this study will help the future developments (commercialization and implementation) of the rapid test and improve patient management and disease prevention.

Field-applicable, high-quality, and low-cost diagnostic tools are urgently needed for Taenia solium . The aim of this paper is to describe the design, challenges, and rationale for the design of a diagnostic accuracy study in low-resource community settings in Zambia. The trial was designed as a prospective study with a two-stage design to evaluate a new point-of-care test (TS POC) for the detection of taeniosis and (neuro)cysticercosis. Participants within randomly selected households were tested with the TS POC test (index test). Participants who tested TS POC positive for taeniosis and/or cysticercosis and a subset of the negatives were requested to give blood and stool samples for reference testing, and to undergo clinical examination and a cerebral CT scan. The difficulties of conducting a clinical trial in settings with limited research and neuroimaging infrastructure as well as peculiarities specifically related to the disease (low prevalence of taeniosis and the lack of a gold standard) were taken into consideration for the design of this study. The two-stage design increased the efficiency of the study by reducing the number of samples, clinical examinations, and CT scans. Simplified flows and sampling processes were preferred over complex follow-up and randomization systems, aiming to reduce bias and increase the generalizability of the study.

Taenia spp. are responsible for a substantial health and economic burden in affected populations. Knowledge of the fate of the eggs of Taenia spp. in the environment and of other factors facilitating the transmission of eggs to intermediate hosts is important for the control/elimination of infections caused by Taenia spp. The aim of this systematic review was to summarize current knowledge of the factors influencing the survival and dispersal of Taenia spp. eggs in the environment. Publications retrieved from international databases were systematically reviewed. Of the 1465 papers initially identified, data were ultimately extracted from 93 papers. The results of this systematic review indicate that survival is favoured at moderate temperatures (0-20 °C). Humidity seems to affect the survival of Taenia spp. eggs more than temperature. Under field circumstances, Taenia spp. eggs have been found to survive for up to 1 year. Taenia spp. eggs are commonly found on vegetables (0.9-30%) and in soil and water samples (0-43%), with their presence posing a risk to the consumer. Invertebrates may act as transport hosts, transferring the infection to an intermediate host, but the importance of this route of transmission is still open to question. Wastewater treatment systems are not capable of entirely eliminating Taenia spp. eggs. Access to surface water and the use of sewage sludge as fertilizer on pastures are important risk factors for bovine cysticercosis. Although information on the survival and spread of Taenia spp. eggs is available, in general the data retrieved and reviewed in this article were old, focused on very specific geographical regions and may not be relevant for other areas or not specific for different Taenia spp. Furthermore, it is unknown whether egg survival differs according to Taenia sp. Future studies are necessary to identify sustainable methods to identify and inactivate parasite eggs in the environment and reduce their spread.

Background: Taenia solium is a zoonotic parasite responsible for neurocysticercosis-a major cause of late-onset acquired epilepsy in humans. Lack of affordable, specific and sensitive diagnostic tools hampers control of the parasite. This study assessed the performance of an antigen detection enzyme-linked immunosorbent assay (Ag-ELISA) in the diagnosis of viable T. solium cysticercosis in naturally infected slaughter-age pigs in an endemic area in Tanzania., Methods: A total of 350 pigs were bled before they were slaughtered and their carcases examined. Serum was analyzed for circulating antigens by using a monoclonal antibody-based B158/B60 Ag-ELISA. Each carcase was examined for the presence of Taenia hydatigena cysticerci and half carcase musculature together with the whole brain, head muscles, tongue, heart and diaphragm were sliced with fine cuts (< 0.5 cm) to reveal and enumerate T. solium cysticerci. Half carcase dissection can detect at least 84% of infected pigs. Prevalence and their 95% confidence intervals (CI) were calculated in Stata 12. Sensitivity, specificity, predictive values and likelihood ratios were determined., Results: Twenty-nine pigs (8.3%, 95% CI: 5.6-11.7%) had viable T. solium cysticerci while 11 pigs had T. hydatigena cysticerci (3.1%, 95% CI: 1.6-5.5%). No co-infection was observed. Sixty-eight pigs (19.4%, 95% CI: 15.4-20%) tested positive on Ag-ELISA; of these, 24 had T. solium cysticerci and 7 had T. hydatigena cysticerci. Sensitivity and specificity were determined to be 82.7% and 86.3%, respectively. Positive and negative predictive values were 35.2% and 98.2%, respectively. Likelihood ratios for positive and negative Ag-ELISA test results were 6.0 and 0.2, respectively. There was a significant positive correlation between the titre of circulating antigens and intensity of T. solium cysticerci (r (348)  = 0.63, P < 0.001)., Conclusions: The Ag-ELISA test characteristics reported in this study indicate that the test is more reliable in ruling out T. solium cysticercosis in pigs, than in confirming it. Hence, a negative result will almost certainly indicate that a pig has no infection, but a positive result should always be interpreted with caution. Estimates of T. solium prevalence based on Ag-ELISA results should, therefore, be adjusted for test performance characteristics and occurrence of T. hydatigena.

A field trial was conducted in Tanzania to determine the effectiveness of TSOL18 vaccine used concurrently with oxfendazole (OFZ), and of OFZ alone, on T. solium cysticercosis determined by organ and half carcase dissection of slaughter age pigs. This study followed a quasi-experimental group design. Suitable trial sites were randomly allocated to either treatment group T1 (OFZ treatment alone [30mg/kg, Paranthic 10%]) or T2 (TSOL18 [1ml, Cysvax] plus OFZ). Three 4-monthly treatments were administered to eligible pigs. A random selection of pigs were necropsied at baseline and at endline, 2-3.5 months after the final treatment. Additionally, untreated pigs from T1 and T2 areas were necropsied at endline to provide contemporaneous comparisons with T1 and T2 pigs. Baseline prevalence of viable T. solium cysticerci for T1 was 25.5% (Exact 95% CI: 13.9, 40.3; n = 12/47), and for T2 was 12.0% (CI: 6.4, 20.0; n = 12/100). At endline, prevalence was 2.8% for T1 (CI: 0.1, 14.5, n = 1/36) and 0% for T2 (CI: 0, 4.7, n = 0/77). Among untreated pigs, three had viable cysticerci, one from T1 area (12.5%, CI: 0.3, 52.7; n = 1/8) and two from T2 area (5.7%, CI: 0.7, 19.2, n = 2/35). Fisher's exact test showed significant changes in prevalence from baseline to endline in both groups (T1: p = 0.005, T2: p = 0.001). Firth's penalized Maximum Likelihood method suggested the changes were not significant relative to their controls (T1: p = 0.245, T2: p = 0.076). These findings showed a significant reduction in the prevalence of viable cysticerci from baseline to endline after both interventions. However, the changes could not be definitively attributed to the interventions due, in part, to small numbers of control pigs. Concurrent administration of the TSOL18 and OFZ cleared infection among assessed pigs whereas infection remained after treatment with OFZ only. Further studies including larger sample sizes would be required for more definitive conclusions. A One Health approach is recommended for rapid and sustainable impact., Competing Interests: The authors have declared that no competing interests exist.

Background: Taenia solium taeniasis/cysticercosis is a disease of substantial economic and public health importance particularly in low-income countries. The disease was reported to be endemic in Mbeya Rural and Mbozi districts, in the southern highlands of Tanzania, the major pig production area in the country. In 2008, using B158/B60 antigen detection enzyme-linked immunosorbent assay (Ag-ELISA), porcine cysticercosis prevalence of up to 32% was reported in the districts. A number of interventions have been implemented in selected villages including an integrated approach consisting of improving pig confinement and selective treatment of pigs with oxfendazole. Mass drug administration with praziquantel targeting schistosomiasis, with an expected effect on T. solium, was also provided to school-age children in the area. This study aimed at providing an update on prevalence and intensities of porcine cysticercosis; and assessing farmers' knowledge, attitudes and practices which could be associated to disease transmission in the area. The study involved a questionnaire survey conducted using face-to-face household interviews with 890 consenting farmers; and carcass dissections performed on 282 pigs randomly selected from the surveyed households., Results: Twenty-six pigs (9.2%) were infected with T. solium; of which two-thirds (65.4%) had light to moderate infection intensities (1-1000 cysticerci), and one-third (34.6%) had heavy intensities (> 1000 cysticerci). Questionnaire results showed that only 5.7% of the respondents perceived T. solium cysticercosis to be an important disease in pigs. About 18.5% of the respondents were aware of T. solium taeniasis, but 32% of them were unaware of how the infection is acquired. Half of the respondents had seen cysticerci in pork, of whom 61% were not aware that consumption of infected pork could cause taeniasis. Latrines were observed to often (90%) lack doors with 45% considered accessible to pigs., Conclusions: This study provided an evidence that the disease was still endemic in the area. Poor knowledge of farmers, attitudes, and risky practices responsible for disease perpetuation were also revealed. A One Health approach targeting the whole area incorporating improvement of farmer knowledge regarding disease transmission needs to be trialed as a feasible approach to control.

Background: Toxoplasma gondii is found worldwide, and consumption of undercooked meat is considered a significant risk factor for human infections. In Denmark, little is known about the distribution of T. gondii, but a recent study revealed a seroprevalence of 34% in Danish indoor sows. The present cross-sectional study aimed to investigate the role of mice for the transmission of T. gondii in Danish indoor sow herds., Results: In total, 56 sow herds were visited, 137 mice were caught by snap traps from 32 farms, and 52 cat faecal samples were collected from 22 farms. Eight percent of the mice were positive for T. gondii DNA, representing 11% of the farms. Significant associations were found between the presence of T. gondii-positive mice and both open feed systems (P= 0.041) and extra rodent control on the farm (P= 0.024). All cat faecal samples were deemed negative for T. gondii by light microscopy examination and real-time polymerase chain reaction analysis., Conclusion: Mice captured inside Danish sow herds were found to be infected with T. gondii and may thus contribute to the transmission of T. gondii to sows, which may explain the high seroprevalence found in Danish pigs.

Background: Despite Taenia solium taeniosis/cysticercosis (TSTC) having been put high on the global agenda of neglected tropical diseases (NTDs), which over the last years has received a lot of attention, there has been no control programmes in place in sub-Saharan Africa, a highly endemic region. This could be attributed to lack of awareness of many stakeholders on the burden and impact of T. solium. This information is essential in guiding TSTC policies, practices and research agendas as well as encouraging cross-sectoral collaboration in the control of this important zoonotic parasite using a One Health approach. National elimination of the parasite is the foundation for global eradication. This will require that substantial country-level information is provided to all key stakeholders. We have mapped out TSTC research evidence in Tanzania to inform on disease burden and potential for integrated control measures., Methodology/principal Findings: A scoping review of all TSTC studies undertaken in Tanzania and published up to December 2018 was conducted. The articles were searched from PUBMED, AJOL, Google Scholar and Google in general. Fifty-one (51) articles met the inclusion criteria and were reviewed. Prevalence of taeniosis of 2.3% - 5.2% was estimated based on copro-antigen ELISA while human cysticercosis of >16% was estimated based on serum antigen ELISA (Ag-ELISA) or IgG Western Blot. Neurocysticercosis (NCC) contributed significantly to epilepsy in adults. Farm prevalence of porcine cysticercosis were 6.0% - 17.4% (lingual examination) and 1.5% - 33.3% (Ag-ELISA). Slaughter-slab prevalence were 0% - 18.2% (routine meat inspection). Lacking latrines, watering pigs with river or pond water, and feeding pigs with potato peels were associated with porcine cysticercosis prevalence. Washing hands by dipping method increased the risk of human cysticercosis. In 2012, the number of DALYs/1000 person-years for NCC-associated epilepsy was 0.7 (95% UI, 0.2-1.6), around 5 million USD (95% UI, 797,535-16,933,477) were spent due to NCC-associated epilepsy and nearly 3 million USD (95% UI, 1,095,960-5,366,038) were potentially lost due to porcine cysticercosis. Three rounds of annual treatment of school-age children with praziquantel significantly reduced prevalence of taeniosis and porcine cysticercosis. Health education was efficacious in improving knowledge and attitudes favourable for control of TSTC while a single dose of oxfendazole 30 mg/kg body weight was efficacious in eliminating T. solium cysticerci from pig musculature., Conclusions/significance: The observed high burden of TSTC and the significant contribution of NCC to epilepsy in Tanzania warrant urgent interventions. Evaluation of best control options should make use of disease transmission dynamics models such as cystiSim, taking into account findings from the field based intervention studies. In addition, locally adapted management guidelines for people suffering from NCC are urgently needed., Competing Interests: The authors have declared that no competing interests exist.

Background: Toxoplasma gondii is an important foodborne zoonotic parasite. Meat of infected animals is presumed to constitute a major source of human infection and may be a driver of geographical variation in the prevalence of anti- T. gondii antibodies in humans, which is substantial in the Nordic-Baltic region in northern Europe. However, data on seroprevalence of T. gondii in different animal species used for human consumption are scattered., Methods: We conducted a systematic review of seroprevalence studies and meta-analysis to estimate the seroprevalence of T. gondii in five animal species that are raised or hunted for human consumption in the Nordic-Baltic region: domestic pigs ( Sus scrofa domesticus ), sheep ( Ovis aries ), cattle ( Bos taurus ), wild boars ( Sus scrofa ), and moose ( Alces alces ). We searched for studies that were conducted between January 1990 and June 2018, and reported in articles, theses, conference abstracts and proceedings, and manuscripts. Subgroup analyses were performed to identify variables influencing the seroprevalence., Findings: From a total of 271 studies identified in the systematic review, 32 were included in the meta-analysis. These comprised of 13 studies on domestic pigs, six on sheep, three on cattle, six on wild boars, and four on moose. The estimated pooled seroprevalence of T. gondii was 6% in domestic pigs (CI 95% : 3-10%), 23% in sheep (CI 95% : 12-36%), 7% in cattle (CI 95% : 1-21%), 33% in wild boars (CI 95% : 26-41%), and 16% in moose (CI 95% : 10-23%). High heterogeneity was observed in the seroprevalence data within each species. In all host species except wild boars, the pooled seroprevalence estimates were significantly higher in animals >1 year of age than in younger animals. Not all studies provided information on animal age, sensitivity and specificity of the serological method employed, and the cut-off values used for defining an animal seropositive., Conclusions: A substantial proportion of animals raised or hunted for human consumption in the region had tested positive for T. gondii . This indicates widespread exposure to T. gondii among animals raised or hunted for human consumption in the region. Large variations were observed in the seroprevalence estimates between the studies in the region; however, studies were too few to identify spatial patterns at country-level.

Background: Taenia solium taeniosis/cysticercosis is a public health and agricultural problem, especially in low-income countries, and has been ranked the top foodborne parasitic hazard globally. In 2012, the World Health Organization published a roadmap that called for a validated strategy for T. solium control and elimination by 2015. This goal has not been met, and validated evidence of effective control or elimination in endemic countries is still incomplete. Measuring and evaluating success of control programmes remains difficult, as locally acceptable targets have not been defined as part of the 2012 roadmap nor from other sources, and the performance of tools to measure effect are limited., Discussion: We believe that an international agreement supported by the tripartite World Health Organization, Food and Agriculture Organization of the United Nations, and World Organisation for Animal Health is needed to facilitate endemic countries in publicising SMART (Specific, Measurable, Achievable/attainable, Relevant, Time-bound) country-level control target goals. These goals should be achievable through locally acceptable adoption of options from within a standardised 'intervention tool-kit', and progress towards these goals should be monitored using standardised and consistent diagnostics. Several intervention tools are available which can contribute to control of T. solium, but the combination of these - the most effective control algorithm - still needs to be identified. In order to mount control efforts and ensure political commitment, stakeholder engagement and funding, we argue that a stepwise approach, as developed for Rabies control, is necessary if control efforts are to be successful and sustainable., Conclusions: The stepwise approach can provide the framework for the development of realistic control goals of endemic areas, the implementation of intervention algorithms, and the standardised monitoring of the evaluation of the progress towards obtaining the control target goals and eventually elimination.

Background: Taenia solium, a zoonotic tapeworm, is responsible for about a third of all preventable epilepsy human cases in endemic regions. In Europe, adequate biosecurity of pig housing and meat inspection practices have decreased the incidence of T. solium taeniosis and cysticercosis. Pigs slaughtered at home may have been raised in suboptimal biosecurity conditions and slaughtered without meat inspection. As a result, consumption of undercooked pork from home slaughtered pigs could pose a risk for exposure to T. solium. The aim of this study was to quantify the risk of human T. solium exposure from meat of home slaughtered pigs, in comparison to controlled slaughtered pigs, in European countries. A quantitative microbial risk assessment model (QMRA) was developed and porcine cysticercosis prevalence data, the percentage of home slaughtered pigs, meat inspection sensitivity, the cyst distribution in pork and pork consumption in five European countries, Bulgaria, Germany, Poland, Romania and Spain, were included as variables in the model. This was combined with literature about cooking habits to estimate the number of infected pork portions eaten per year in a country., Results: The results of the model showed a 13.83 times higher prevalence of contaminated pork portions from home slaughtered pigs than controlled slaughtered pigs. This difference is brought about by the higher prevalence of cysticercosis in pigs that are home raised and slaughtered. Meat inspection did not affect the higher exposure from pork that is home slaughtered. Cooking meat effectively lowered the risk of exposure to T. solium-infected pork., Conclusions: This QMRA showed that there is still a risk of obtaining an infection with T. solium due to consumption of pork, especially when pigs are reared and slaughtered at home, using data of five European countries that reported porcine cysticercosis cases. We propose systematic reporting of cysticercosis cases in slaughterhouses, and in addition molecularly confirming suspected cases to gain more insight into the presence of T. solium in pigs and the risk for humans in Europe. When more data become available, this QMRA model could be used to evaluate human exposure to T. solium in Europe and beyond.

Toxoplasma gondii is a zoonotic parasite of worldwide importance. In this study, we estimated T. gondii seroprevalence in extensively farmed wild boars in Denmark, where little is known about T. gondii in animal hosts. Our study focused on wild boars because they are considered good indicator species for the presence of T. gondii, and wild boar meat is used for human consumption. Serum samples from 101 wild boars collected in 2016-2018 from five different locations from the continental part of Denmark, Jutland, were screened for anti-T. gondii antibodies. The samples were analysed using a commercial indirect enzyme-linked immunosorbent assay (ELISA). Samples from 28 (27.7%) of the 101 wild boars tested positive with the ELISA. The odds for a wild boar to test seropositive were higher if it was sampled during the hunting season 2017-2018 than during 2016-2017 and if it was reported to be at least 1 year old than if it was younger (logistic regression model with the two variables: odds ratios 17.5 and 3.9, respectively). A substantial proportion of the investigated extensively farmed wild boars had been exposed to T. gondii. Moreover, the parasite appeared widespread, at least in the continental part of Denmark, Jutland, as seropositive wild boars were found from all five sampled locations. Assuming seropositivity indicates hosting viable parasites, consumption of undercooked wild boar meat from Denmark is a potential source of T. gondii infections to other hosts, including humans.

Background: The zoonotic parasite Taenia solium is endemic in Angónia district, Tete province, Mozambique, though the burden of the disease complex is unknown., Methods: As part of two cross-sectional studies on human and porcine cysticercosis in the area, unique epidemiological and cost data were collected in Angónia district, Mozambique in 2007. These data provided the basis for the assessment of the societal cost of T. solium in the district, which estimates the impact of the disease on human and pig populations and includes both health and economic approaches in the analysis., Results: Approximately 0.7% (95% Uncertainty Interval (UI), 0.4-0.9) and 0.4% (95% UI, 0.2-0.6) of the total population in the district was estimated to suffer from neurocysticercosis (NCC)-associated epilepsy and headache. The estimated average number of disability-adjusted life years (DALYs) due to NCC-associated epilepsy and headache was 6 (95% UI, 4-8) per thousand persons per year. The total annual costs due to T. solium cysticercosis were estimated at 90,000 USD (95% UI, 39,483-201,463) of which 72% (95% UI, 45-91) were costs linked to human cysticercosis and 28% (95% UI, 9.5-55) to pig production losses. The annual economic burden per NCC-associated epilepsy case in the district amounted to 33 USD (95% UI, 10-76)., Conclusions: In this highly endemic area of Mozambique a large number of individuals suffer from symptoms associated with NCC. Healthy years of life are lost and people are left living with disabilities. Infected pork poses a serious risk to the community and affects the economy of smallholder farmers. Cost for treatment and hospitalization of patients with NCC-associated epilepsy, and lack of productivity and inability of suffering patients to work, further hinder socioeconomic development. Feasible solutions framed within a country specific algorithm and stepwise approaches are needed to control the parasite in the country.

Taenia solium taeniosis/cysticercosis was declared eradicable by the International Task Force for Disease Eradication in 1993, but remains a neglected zoonosis. To assist in the attempt to regionally eliminate this parasite, we developed cystiSim, an agent-based model for T. solium transmission and control. The model was developed in R and available as an R package (http://cran.r-project.org/package=cystiSim). cystiSim was adapted to an observed setting using field data from Tanzania, but adaptable to other settings if necessary. The model description adheres to the Overview, Design concepts, and Details (ODD) protocol and consists of two entities-pigs and humans. Pigs acquire cysticercosis through the environment or by direct contact with a tapeworm carrier's faeces. Humans acquire taeniosis from slaughtered pigs proportional to their infection intensity. The model allows for evaluation of three interventions measures or combinations hereof: treatment of humans, treatment of pigs, and pig vaccination, and allows for customary coverage and efficacy settings. cystiSim is the first agent-based transmission model for T. solium and suggests that control using a strategy consisting of an intervention only targeting the porcine host is possible, but that coverage and efficacy must be high if elimination is the ultimate goal. Good coverage of the intervention is important, but can be compensated for by including an additional intervention targeting the human host. cystiSim shows that the scenarios combining interventions in both hosts, mass drug administration to humans, and vaccination and treatment of pigs, have a high probability of success if coverage of 75% can be maintained over at least a four year period. In comparison with an existing mathematical model for T. solium transmission, cystiSim also includes parasite maturation, host immunity, and environmental contamination. Adding these biological parameters to the model resulted in new insights in the potential effect of intervention measures., Competing Interests: The authors have declared that no competing interests exist.

Taenia solium is found throughout sub-Saharan Africa and co-endemic with schistosomiasis in many regions. Taenia solium leads to taeniosis and neurocysticercosis - the leading cause of preventable epilepsy globally. This study aimed to assess the effects of the National Schistosomiasis Control Programme on prevalence of taeniosis and porcine cysticercosis over a four year period in Tanzania. School-based mass drug administration (MDA) of praziquantel was carried out based on schistosomiasis endemicity. Four human and five porcine cross-sectional surveys were carried out from 2012 to 2015 in Mbozi and Mbeya district in Tanzania. Three rounds of school-based MDA of praziquantel were delivered in Mbozi and two in Mbeya. The prevalence of taeniosis and porcine cysticercosis was estimated annually. Stool samples were collected from humans and prevalence of taeniosis estimated by copro-Ag-ELISA. Blood samples from pigs were collected to estimate cysticercosis prevalence by Ag-ELISA. "Track-and-treat" of taeniosis cases was carried out after each survey. In total 12082 stool samples and 4579 porcine serum samples were collected. Significantly fewer children (≤ 15) from Mbozi were infected throughout the study than children from Mbeya who showed a significant decrease in copro-Ag prevalence after the first treatment only. During the final survey in Mbozi the prevalence of taeniosis in adults (1.8%) was significantly lower (p = 0.031, OR 0.40, CI: 0.17-0.89), compared to baseline (4.1%). The prevalence of porcine cysticercosis (8%) had also dropped significantly (p = 0.002, OR 0.49, CI: 0.32-0.76) in this district compared to baseline (13%), whereas no significant difference was seen in Mbeya compared to baseline. The study suggests that three rounds of MDA targeting schistosomiasis in school-aged children combined with 'track-and-treat' contributed to a reduction in prevalence of T. solium in this population, and also had a spillover effect on adults in treated areas as well as reducing the prevalence of T. solium in the intermediate pig host population. Elimination of T. solium in this area would require a One Health approach.

Background: This study aimed to map the distribution of Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa. These two major neglected tropical diseases are presumed to be widely distributed in Africa, but currently the level of co-distribution is unclear., Methods: A literature search on T. solium taeniosis/cysticercosis was performed to compile all known studies on the presence of T. solium and apparent prevalence of taeniosis and porcine cysticercosis in Africa. Studies were geo-referenced using an online gazetteer. A Bayesian framework was used to combine the epidemiological data on the apparent prevalence with external information on test characteristics to estimate informed district-level prevalence of taeniosis and porcine cysticercosis. Districts with T. solium taeniosis/cysticercosis presence were cross-referenced with the Global Neglected Tropical Diseases Database for schistosomiasis presence., Results: The search strategies identified 141 reports of T. solium in Africa from 1985 to 2014 from a total of 476 districts in 29 countries, 20 with porcine cysticercosis, 22 with human cysticercosis, and 16 with taeniosis, in addition to 2 countries identified from OIE reports. All 31 countries were considered, on national scale, to have co-distribution with schistosomiasis. Presence of both parasites was confirmed in 124 districts in 17 countries. The informed prevalence of taeniosis and porcine cysticercosis were estimated for 14 and 41 districts in 10 and 13 countries, respectively., Conclusions: With the paucity of data, T. solium infection is grossly under-reported and expected to be more widespread than this study suggests. In areas where co-distribution occurs there is a need for increased emphasis on evaluation of integrated intervention approaches for these two helminth infections and allocation of resources for evaluating the extent of adverse effects caused by mass drug administration.

Background: Porcine cysticercosis is an emerging agricultural problem in sub-Saharan Africa. This has been documented primarily through cross-sectional studies, however detailed knowledge of the transmission dynamics of this disease in sub-Saharan Africa is lacking. This study aims to describe seasonal variations in sero-prevalence of antigen ELISA positive porcine cysticercosis in an endemic area., Methods: A longitudinal study composed of three cross-sectional surveys was carried out in Mbeya Region, Tanzania; the first two six months apart (March/April 2012 and October/November 2012) and the last eight months later (July/August 2013). Venous blood was collected from pigs in 22 villages and analysed using Ag-ELISA., Results: In each survey between 800-1000 serum samples were collected. The first survey revealed a cysticercosis sero-prevalence of 15% (n = 822, 95% CI: 13-18%). The sero-prevalence had significantly increased to 24% (p < 0.001, χ2-test, n = 812, 95% CI: 21-27%) at the time of the 6 month follow-up. At 14-months the sero-prevalence had dropped to 20% (p = 0.053, χ2-test, n = 998, 95% CI: 18-23%). Overall, this was a reduction in sero-prevalence compared with a study conducted in 2007 in the same area, where 31% (186/600) of pigs were found positive., Conclusion: Confined pigs did not have a lower sero-prevalence compared to free roaming pigs in any of the three surveys. Several factors may have contributed to the observed fluctuations such as African swine fever or seasonal variation in local crop production practices. Also, as the Ag-ELISA assay used is not species specific, variation in transmission of Taenia hydatigena could potentially influence the results. The observed fluctuations contradict a theoretical model which predicts a stable equilibrium, which only considers a two-compartment (pig and human) model excluding the effect of the environment. Whether the disease has an endemic equilibrium, or undergoes fluctuations dependent on extrinsic and/or socio-economic factors remains to be elucidated.

Background: The World Health Organization aims for complete morbidity control of fishborne zoonotic trematodes (FZT) in endemic areas by 2020. The main intervention tool for achieving this goal is regular use of preventive chemotherapy by offering praziquantel to those at risk in endemic areas. The purpose of this study was to investigate the effectiveness of preventive chemotherapy to control FZT in an endemic area in Northern Vietnam., Methodology and Principle Findings: We followed a cohort of 396 people who fulfilled the criteria for receiving preventive chemotherapy. Stool samples were examined by Kato-Katz technique for the presence of trematode eggs before, and two, 16, 29 and 60 weeks after preventive chemotherapy. The prevalence of trematode eggs in stool was 40.2% before, 2.3% two weeks after and increased to a cumulative prevalence of 29.8% sixty weeks after preventive chemotherapy., Conclusions: The effectiveness of preventive chemotherapy as a main component in control of FZT is not well documented in most endemic areas. We found a high reinfection rate within the first year after preventive chemotherapy. Since these trematodes are zoonoses, preventive chemotherapy may not have sufficient impact alone on the transmission to have a lasting effect on the prevalence. Animal reservoirs and farm management practices must be targeted to achieve sustainable control of fishborne zoonotic trematode infections, hence control programs should consider a One Health approach.

Advocacy for neglected zoonotic diseases (ADVANZ) is a One Health Neglected Zoonotic Diseases (NZDs) project, funded by the European Commission through its 7th framework programme. The initiative aims at persuading decision makers and empowering stakeholders at local, regional, and international levels towards a coordinated fight against NZDs. ADVANZ is establishing an African platform to share experiences in the prevention and control of NZDs. The platform will compile and package existing knowledge or data on NZDs and generate evidence-based algorithms for improving surveillance and control with the ultimate aim of eliminating and eradicating these diseases. The platform will serve as a forum for African and international stakeholders, as well as existing One Health and NZD networks and harness and consolidate their efforts in the control and prevention of NZDs. The platform had its first meeting in Johannesburg, South Africa in March 2013.

Background: Fish-borne zoonotic trematodes (FZT) infections including liver- and minute intestinal flukes are common in Southeast Asia in both humans and domestic animals eating raw fish and since 2010, the liver flukes are recognised as neglected tropical diseases by WHO. Mass drug treatment with praziquantel is advised for humans, but no recommendations for control of the FZT in the reservoir hosts exist., Methodology/principal Findings: A study was conducted to assess the ability of praziquantel treatment for control of FZT in farm dogs in an endemic area in Northern Vietnam. Initially, 101 dogs from 73 households were examined for small trematode eggs in their faeces. Forty seven copro-positive dogs were included in the study. Thirty eight dogs received treatment with a single dose of 40 mg/kg of praziquantel. A group of nine dogs were left untreated. Coprological examination for small trematode eggs was performed on day 0, 3, 10, 30, 60, 90 and 120 post treatment. Farmers were questioned about dog keeping practises. All dogs were copro-negative for small trematode eggs on both day 3 and 10 post treatment. From day 30 onwards previously negative dogs became positive again. The reinfection rates were 26.3% (day 30), 45.5% (day 60), 53.1% (day 90), 61.3% (day 120).The nine untreated dogs remained positive throughout the study period. There was no difference in the intensity of infection at day 0 and 120 neither in the treated or untreated group., Conclusion: Dogs had easy access to raw fish and did not receive treatment against flukes by their owner. More than 50% of the dogs were reinfected 3 months post treatment. We do not recommend controlling FZT infections in dogs by anthelmintic treatment alone since reinfection occurs fast under the existing farm management systems.

Porcine cysticercosis, an infection caused by Taenia solium metacestodes, is continuously being reported in low-income countries of Latin America, Asia, and sub-Saharan Africa. The disease was declared eradicable by the International Task Force for Diseases Eradication (ITFDE) in 1993, and it is listed among the 17 WHO Neglected Tropical Diseases and Neglected Zoonoses that are potentially eradicable. In view of that, WHO has proposed a step-wise approach to its elimination, including chemotherapy of infected pigs. Different drugs have been tested on porcine cysticercosis with varying efficacies. These include flubendazole, fenbendazole, albendazole, albendazole sulphoxide, oxfendazole, praziquantel, and nitazoxanide. This review summarises available information on the efficacies and adverse effects shown by these drugs in pigs. Oxfendazole has shown to be effective for the control of porcine cysticercosis; however, it needs to be integrated with other control approaches. There is a need for standardised guidelines for evaluating the efficacy of anthelmintics against porcine cysticercosis, and more efficacy studies are needed since the conclusions so far are based on a limited number of studies using few infected pigs.

Background: Infections with fish-borne zoonotic trematodes (FZT) including the minute intestinal fluke, Haplorchis pumilio, are highly prevalent in Southeast Asia. However, little is known about the infection dynamics and clinical symptoms in the final hosts which include a range of animal species and man. We aimed to generate such information using an experimental model with H. pumilio in foxes., Method: Eight commercially bred foxes were each orally infected with 2000 H. pumilio metacercariae. Another three foxes served as uninfected controls. Faecal examination for eggs was performed twice weekly. The body weight was measured, standard haematological and biochemical analysis were performed regularly. All foxes were euthanized at day 56 post infection (p.i.). Adult worms were quantified and location in the small intestine noted., Results: Anorexia was observed in all infected foxes starting day 12 p.i. and lasting for approximately a week. A weight loss was noticed in the infected group in weeks 3-6 p.i. Five of eight infected foxes excreted H. pumilio eggs day 9 p.i. onwards, the remaining three started on day 13 p.i. Mean (± SD) faecal egg counts showed an initial peak at day 16-20 with a maximum of 1443 ± 1176 eggs per gram of faeces (epg), where after a stable egg output around 4-500 epg was seen. Worm burdens ranged between 116-2070 adult flukes with a mean (± SD) worm recovery of 948 ± 666. The majority of worms were found in the lower part of the jejunum. Total white blood cell and lymphocyte counts were significant lower in the infected group from first week p.i. onwards and throughout the study period. A significantly lower level of eosinophils was found in week 2 p.i. and transient anaemia was seen in week 2 and 4 p.i., Conclusion: This study showed a short prepatency period, an initial peak in egg excretion, establishment of infection in all animals with predilection site in the lower jejunum and a marked but transient clinical effect of the infection. The findings on egg output and prepatency should be taken into consideration when control programs targeting dogs and other reservoir hosts are to be established.

Background: Taenia solium cysticercosis/taeniosis is emerging as a serious public health and economic problem in many developing countries. This study was conducted to determine prevalence and risk factors of human T. solium infections in Mbeya Region, Tanzania., Methods and Findings: A cross-sectional survey was conducted in 13 villages of Mbozi district in 2009. Sera of 830 people (mean 37.9±11.3 years (SD); 43% females) were tested for circulating cysticerci antigen (Ag-ELISA) and antibody (Ab-ELISA). A subset of persons found seropositive by Ag-ELISA underwent computed tomography (CT) scan of the brain for evidence of neurocysticercosis. Stool samples from 820 of the same participants were tested for taeniosis by copro-antigens (copro-Ag-ELISA) and formol-ether concentration technique. Cases of T. solium taeniosis were confirmed serologically by EITB assay (rES38). A questionnaire was used for identification of risk factors. Active cysticercosis by positive Ag-ELISA was found in 139 (16.7%) persons while anti-cysticercal antibodies were detected in 376 (45.3%) persons by Ab-ELISA. Among 55 persons positive for Ag-ELISA undergoing CT scan, 30 (54.6%) were found to have structures in the brain suggestive of neurocysticercosis. Using faecal analysis, 43 (5.2%) stool samples tested positive for taeniosis by copro-Ag-ELISA while Taenia eggs were detected in 9 (1.1%) stool samples by routine coprology. Antibodies specifically against adult T. solium were detected in 34 copro-Ag-ELISA positive participants by EITB (rES38) indicating T. solium taeniosis prevalence of 4.1%. Increasing age and hand washing by dipping in contrast to using running water, were found associated with Ag-ELISA seropositivity by logistic regression. Gender (higher risk in females) and water source were risk factors associated with Ab-ELISA seropositivity. Reported symptoms of chronic severe headaches and history of epileptic seizures were found associated with positive Ag-ELISA (p≤0.05)., Conclusion: The present study indicates T. solium infection in humans is highly endemic in the southern highlands of Tanzania.

Oxfendazole is recommended as the drug of choice for treating porcine cysticercosis. The drug does not kill brain cysts and is not registered for use in pigs. Latest its safety in the recommended dose has been questioned. The aim of this study was to investigate two alternative anthelminthics. The efficacy of praziquantel and ivermectin was compared to oxfendazole In Vitro on Taenia solium. Cysts of T. solium were isolated from infected pork and incubated in culture media together with the drugs. The degree of evagination was used as effect measurement and determined after 6 hours. Praziquantel had a half maximal effective concentration (EC(50)) of value 0.006 ± 0.001 μg/mL. Ivermectin did not show any impact on the evagination in concentrations from 0.001 to 30 μg/mL and neither did oxfendazole in concentrations from 0.001 to 50 μg/mL.

A randomized controlled field trial to evaluate the effectiveness of a single oral dose of 30 mg/kg of oxfendazole (OFZ) treatment for control of porcine cysticercosis was conducted in 4 rural villages of Angónia district, north-western Mozambique. Two hundred and sixteen piglets aged 4 months were selected and assigned randomly to OFZ treatment or control groups. Fifty-four piglets were treated at 4 months of age (T1), while another 54 piglets were treated at 9 months of age (T2) and these were matched with 108 control pigs from the same litters and raised under the same conditions. Baseline data were collected on the prevalence of porcine cysticercosis using antigen ELISA (Ag-ELISA), as well as knowledge and practices related to Taenia solium transmission based on questionnaire interviews and observations. All animals were followed and re-tested for porcine cysticercosis by Ag-ELISA at 9 and 12 months of age when the study was terminated. Overall prevalence at baseline was 5.1% with no significant difference between groups. At the end of the study, 66.7% of the controls were found positive, whereas 21.4% of the T1 and 9.1% of the T2 pigs were positive, respectively. Incidence rates of porcine cysticercosis were lower in treated pigs as compared to controls. Necropsy of 30 randomly selected animals revealed that viable cysts were present in none (0/8) of T2 pigs, 12.5% (1/8) of T1 pigs and 42.8% (6/14) of control pigs. There was a significant reduction in the risk of T. solium cysticercosis if pigs were treated with OFZ either at 4 months (OR = 0.14; 95% CI: 0.05-0.36) or at 9 months of age (OR = 0.05; 95% CI: 0.02-0.16). Strategic treatment of pigs in endemic areas should be further explored as a means to control T. solium cysticercosis/taeniosis.

Taenia solium is an important zoonosis in many developing countries. Cysticercosis poses a serious public health risk and incurs sizeable economic losses to pig production. Because data on the epidemiology of porcine cysticercosis in Mozambique are scarce, the present study was conducted to determine the prevalence and risk factors for porcine cysticercosis. A cross-sectional survey was carried out in 11 villages in Angónia district, Tete province in northwestern Mozambique. Between September and November, 2007, a total of 661 pigs were tested serologically and examined by tongue inspection. Serum samples were tested for the presence of circulating parasite antigen using a monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (Ag-ELISA). In addition, a questionnaire survey to collect information on pig production, occurrence and transmission of porcine cysticercosis, risk factors and awareness of porcine cysticercosis was conducted in the selected households from which pigs were sampled. Two hundred thirty-one samples (34.9%) were found positive by the Ag-ELISA, while by tongue inspection on the same animals cysticerci were detected in 84 pigs (12.7%). Increasing age (OR = 1.63; 95% CI = 1.13-2.37) and free-range pig husbandry system (OR = 3.81; 95% CI = 2.08-7.06) were important risk factors for porcine cysticercosis in the district. The present findings indicate that porcine cysticercosis is endemic in the region, and that increasing pig age and pig husbandry practices contribute significantly to porcine cysticercosis transmission. Further epidemiological studies on the prevalence and transmission of porcine cysticercosis in rural communities in Mozambique are needed to enable collection of more baseline data and implementation of effective control strategies within the country.

More sensitive methods for diagnosing infection with Schistosoma japonicum are needed as control becomes more effective. We compared a real-time polymerase chain reaction (PCR) for stool samples with conventional diagnostic methods in a study of 1,727 persons from Anhui Province, China. Seroprevalence determined by using an indirect hemagglutination assay (IHA) was much higher (26.1%) than the prevalence in stool-based tests, which were 5.3%, 3.2%, and 3.0% for PCR, hatching test, and Kato-Katz thick smear, respectively. A large proportion of the positive stool samples were only positive in one or two tests. The PCR showed better agreement with IHA than the other two stool-based tests. A commonly used diagnostic algorithm with initial screening for antibodies and subsequent testing with the Kato-Katz thick smear of the seropositive results would have resulted in treatment of 22 people compared with 50 people if the PCR replaced the Kato-Katz thick smear. As prevalence and intensity decrease, the benefit of increased sensitivity using the PCR must be weighed against additional costs.

Fish-borne zoonotic trematodes (FZT) pose a risk to human food safety and health and may cause substantial economic losses in the aquaculture industry. In Nghe An Province, Vietnam, low prevalence of FZT for fish farmers but high prevalence for fish indicate that reservoir hosts other than humans may play a role in sustaining transmission. To determine whether domestic animals may be reservoir hosts, we assessed prevalence and species composition of FZT infections in dogs, cats, and pigs in a fish-farming community in Vietnam. Feces from 35 cats, 80 dogs, and 114 pigs contained small trematode eggs at 48.6%, 35.0%, and 14.4%, respectively; 7 species of adult FZT were recovered from these hosts. These results, combined with data from previous investigations in this community, imply that domestic animals serve as reservoir hosts for FZT and therefore must be included in any control programs to prevent FZT infection in humans.

Background: The endemic countries are in a diagnostic dilemma concerning Schistosoma japonicum with increasing difficulties in diagnosing the infected individuals. The formol-ethyl acetate sedimentation concentration technique is preferred by many clinical microbiology laboratories for the detection of parasites in stool samples. It is potentially more sensitive than the diagnostic methods traditionally used., Methodology/principal Findings: We evaluated the technique for detection of low-intensity S. japonicum infections in 106 stool samples from China and used a commercial kit, Parasep Midi Faecal Parasite Concentrator. One stool sample and one serum sample were collected from each person. As reference standard we used persons positive by indirect hemagglutination in serum and positive by Kato-Katz thick smear microscopy (three slides from a single stool), and/or the hatching test. We found the sedimentation technique to have a sensitivity of only 28.6% and specificity of 97.4%., Conclusion/significance: This study indicates that the sedimentation technique has little to offer in the diagnosis of low-intensity S. japonicum infections, at least when only a single stool sample is examined.

Opisthorchis viverrini is an important food-borne trematode in Southeast Asia. The infection causes significant morbidity in terms of hepatobiliary diseases and cholangiocarcinoma. The aim of this study was to improve the sensitivity of the PCR-based diagnosis of O. viverrini infection. A new fecal DNA extraction protocol for the detection of O. viverrini DNA using cetyltrimethyl-ammoniumbromide to remove PCR inhibitor was used and compared with the commercial stool kit method. The sensitivity of the new test was 79.3%, compared with the 44.8% of the previous method (P < 0.01). PCR-positive tests identified several cases judged parasite negative by the parasitological method (28.6%), indicating the new test's advantage in the diagnosis of individuals with light infections.

The pig is a natural host for Schistosoma japonicum and a useful animal model of human infection. The aim of the present study was to assess the differences between the cytokine profiles in prenatally or postnatally S. japonicum exposed pigs. Seven prenatally exposed pigs, 7 postnatally exposed pigs and 4 uninfected control pigs were compared 27 weeks post exposure. Variables included worm burdens, tissue egg counts, liver pathology and mRNA levels of IL-2, IL-4, IL-10, IL-12, TNF-alpha, TGF-beta1 and IFN-gamma in the liver and the caecum, assessed by RT-PCR. Infection intensity and level of septal fibrosis were significantly higher in the postnatal group compared to the prenatal group (P < 0.05). A significant increase of IL-4 (P < 0.01), IL-10 (P < 0.01), IL-12 (P < 0.01) and TNF-alpha (P < 0.05) mRNA level was also observed in the caecum of prenatally infected animals compared to the control group (P < 0.01). The prenatal group showed higher levels of TGF-beta1 in the liver compared with the postnatally infected group (P< 0.05) and the control group (P< 0.01). This suppressive immune response correlated with previously reported low hepatic pathogenesis in prenatally exposed pigs.

The aim of the present study was to evaluate the efficacy of praziquantel treatment of Schistosoma japonicum infections in cattle and water buffaloes and to assess the natural rate of reinfection after treatment. The studies were conducted on 2 islands in the Yangtze River, Anhui province, China, from March 2003 to January 2004. The efficacy of praziquantel was 97% when applied orally wrapped in tree leaves at the recommended doses. The efficacy was measured using a miracidium hatching technique on fecal samples collected 20 days after treatment. The treatment did not give rise to any major side effects. Reinfection after treatment was high and occurred throughout the year in both cattle and water buffaloes. Age-related resistance was only observed in water buffaloes. It is concluded that although praziquantel is highly effective against S. japonicum in cattle and water buffaloes, a single annual treatment strategy does not effectively control transmission. New strategies for integrated control of animal schistosomiasis are needed to control schistosomiasis transmission more effectively in farm areas of China.

This study elucidated the fate of prenatal infections in piglets born by dams repeatedly infected before and during pregnancy with Schistosoma japonicum. Independent variables included repeated infections of the dams and treatment or challenge infection (or both) of the prenatally exposed piglets. Dependant variables were worm counts, fecal and tissue egg counts, weight gain, and gross pathological observations. Fifteen female piglets (the dams) were included, of which 6 received repeated infections with S. japonicum during 6 mo. All dams were inseminated and 10 wk pregnant; 12 of the dams were infected with S. japonicum, of which 6 had been repeatedly infected. Three dams remained uninfected. Eight weeks after delivery, the prenatally exposed piglets (the offspring) were grouped, and 6 of the 12 groups were treated with praziquantel. Four weeks after treatment, 5 groups of piglets were infected with S. japonicum. Groups of piglets were killed either 12 or 22 wk after delivery. Repeated infections of the dam did not prevent establishment of a congenital infection in the pig fetuses. Piglets born with a congenital infection were not resistant to a S. japonicum challenge infection given 12 wk after birth. Neither did praziquantel effectively cure the piglets nor did treatment of the prenatally infected piglets prevent establishment of a challenge infection given 4 wk after treatment. Results of the present study indicate that prenatal exposure, independently of the dam's infection status, may change the host response to challenge infections and treatment after birth.

To elucidate aspects of pathogenesis of congenital infections with Schistosoma japonicum, 5 Danish crossbred sows were infected during late pregnancy with a Chinese isolate of S. japonicum, and 17 of their offspring (fetuses and piglets) were examined 7, 20. 34, 54, and 69 days postinfection (PI). Organ samples were collected for histopathological examination with emphasis on liver and lung. Samples of the corresponding placenta were also collected from fetuses at postmortem examinations. Perfusions were performed on some of the fetuses to recover schistosomes, and in addition, amniotic fluid was examined for schistosomes. A schistosomulum was found in a 99-day-old fetus 3 wk PI. Eggs were found in meconium from 109-day-old fetuses 34 days after infection of the dam, showing that the prepatent time was the same as in postnatal infections. Piglets examined 54 and 69 days PI had inflammatory reactions in their livers, and progression toward healing and repair of the inflammatory reaction occurred from 54 to 69 days PI. This pilot study is one of the bases for the model of congenital schistosomiasis used currently at the Danish Centre for Experimental Parasitology.

The present study investigated whether Schistosoma japonicum or Schistosoma bois could establish prenatally in lambs. Three ewes were exposed to S. japonicum by intramuscular injection of cercariae, and 3 ewes were exposed to S. bovis cercariae using the leg-emerging technique approximately 2 mo before delivery, and 1 age-matched pregnant ewe served as an uninfected control. The study lasted 18-20 wk after infection, which was 8-9 wk after delivery. All 6 exposed ewes became infected with either S. bovis or S. japonicum. Eight lambs were borne by the 7 ewes, of which 1 (S. bovis exposed) was dead and 1 (S. japonicum exposed) died at delivery. Of the 3 S. japonicum-exposed lambs, 2 were found infected. Four lambs born of S. bovis-exposed ewes were negative. Despite having no worms, these 4 S. bovis-exposed lambs as well as the 1 negative S. japonicum-exposed lamb had, in contrast to the nonexposed control lamb, few, but distinct, liver granulomas dominated by eosinophils and giant cells with large central necrotic areas but with no remnants of eggs or worms. Hence, congenital infection was demonstrated in S. japonicum-infected lambs, but not in S. bovis-infected ones.

The aim of the present study was to assess the effect of a congenital Schistosoma japonicum infection on the establishment, fecundity, and pathogenicity of a postnatal challenge infection. Five prenatally S. japonicum-infected piglets received a challenge infection (prenatal + challenge group), 5 prenatally infected piglets were followed without challenge (prenatal group), and 10 piglets, born by unexposed sows, served as challenge controls (challenge control group). Challenge infections were given 8 wk after the piglets were born (14 wk after the primary infection of the sows), and the study lasted another 11 wk. Variables included worm burden, tissue egg count, and liver pathology. Worm establishment and tissue egg count were comparable in the prenatal + challenge group and in the challenge control group, both exceeding at a statistically significant level those in the prenatal group. No difference in worm fecundity (eggs/female worms/g tissue) was seen between the 3 groups. Liver pathology (i.e., portal and septal fibrosis) was more severe in the challenge control group compared to the other groups. A congenital S. japonicum infection in piglets thus affected neither establishment nor fecundity of a postnatal challenge infection. In spite of this, the challenge infection gave rise to much less liver pathology than the similarly sized challenge control infection.

A survey of helminths in domestic pigs was conducted in Khong District, Laos, to elucidate if these domestic animals could act as definitive hosts for Schistosoma mekongi and to obtain a general overview of their helminthological infection status. Fecal samples were collected from 98 pigs. Twelve pigs (12.2%) were found to excrete S. mekongi eggs. Infection was confirmed by detection of S. mekongi eggs in tissues of liver, rectum, and cecum of 2 pigs. A total of 75.8% of the pigs was infected with 1 or more helminth species. This study showed that pigs may act as a definitive host for S. mekongi.

Background: The Norwegian Board of Health has proposed to divide the delivery units into three categories. For several of today's smaller consultant managed units this could lead to a reclassification into midwife managed units., Material and Methods: During 1997 and 1998 the community hospital in Lofoten has tried out a modified type of midwife managed unit. By a continuous selection process a high risk and a low risk group of gravidas were identified. The high risk group was referred to the central hospital in Bodø, while the low risk group was offered to deliver locally., Results: Previously more than 90% delivered at the community hospital in Lofoten, while approximately 70% still delivered locally during the trial period. There were no deliveries during transport and no serious complications for mother or child caused by the new system. The community hospital had facilities for performing emergency caesarean sections. In 1997 nine caesarean sections out of 211 deliveries and in 1998 four out of 224 were performed. The caesarean section rate for the total population was lower during the trial period than over the previous five years., Interpretation: A modified midwife managed unit could be a good alternative for small consultant managed units if the Norwegian Board of Health's proposal is carried through.

Congenital transmission of Schistosoma japonicum in pigs was investigated by experimentally infecting sows at four weeks gestation (n = 3), 10 weeks gestation (n = 3), or a few weeks prior to insemination (n = 2). None of the piglets born to sows infected prior to insemination or in early pregnancy were found to be infected. However, all of the piglets (n = 26) born to sows infected at 10 weeks gestation were found to harbor schistosomes with S. japonicum eggs recovered from both their feces and livers. The findings show that congenital S. japonicum infection of pigs can occur if sows are infected during mid-to-late pregnancy and may have important implications not only for pigs but also for other mammalian hosts of schistosomes, including humans.

Sixteen non-infected control pigs housed together with 16 pigs infected with Trichuris suis, excreted T. suis eggs in their faeces (range 20-4, 960 eggs per gram faeces (EPG)). When the control pigs were moved to clean pens, their egg counts dropped to zero EPG within five days. A significant correlation was found between T. suis egg counts of infected and control pigs penned together (r = 0.89, P < 0.001). These results suggest that false-positive faecal egg counts may be the result of coprophagia.

Parasitologic, clinicopathologic, and pathologic aspects of Schistosoma japonicum infections of varying durations and intensities were studied in growing pigs injected intramuscularly with a dose of either 0, 100, 500, or 2,000 cercariae and killed at 4, 11, 17, or 24 weeks postinfection (PI). The number of viable worm pairs decreased significantly in the high dose group after 11 weeks PI but not in the lower dose groups; however, a stable population of immature worms persisted throughout the study in all dose groups. Liver egg counts also tended to decrease in the high dose group after 11 weeks but not in the other groups. Fecal egg excretion began at six weeks PI, was highest at eight weeks PI with a pronounced peak occurring only in the high dose group, and then decreased to low levels by 14 weeks PI in all groups. Egg counts from the feces as well as the liver correlated strongly with worm pair numbers during the acute phase of infection. The only clinicopathologic abnormality observed was an increase in circulating eosinophils corresponding to cercarial dose in all infected pigs by week six with peak counts occurring between six and eight weeks PI. The pigs exhibited no clinical signs of disease aside from diarrhea at the onset of patency. However, lesions were present throughout the large intestine of all infected pigs from 11 weeks PI, gradually decreasing with time. Severe liver fibrosis occurred in the 500 and 2,000 dose groups mainly at 11 weeks PI and then decreased in severity. In the liver, but not in the intestine, the severity of lesions at all time points was proportional to the cercarial dose given. The results indicate that after several weeks of patency, pigs with high intensities of S. japonicum infection are able to effectively eliminate the majority of adult worms while maintaining a stable population of immature schistosomes.

A technique was developed for in vivo labeling of adult Schistosoma japonicum worms using 35S bound to methionine and cysteine. The isotope was applied in an in vivo labeling system in which Oncomelania hupensis snails harboring a patent S. japonicum were individually exposed to the label. Following exposure to cercariae, mice were perfused after 6 wk. For autoradiography and fluorography, the worms were mounted on cardboard, covered with x-ray films, and exposed for 5 wk. With both techniques, images of both male and female worms were obtained in the 1- and 2-microCi groups, but not in the 0.5-microCi group. Fluorography proved more sensitive than autoradiography. Snail survival, labeled cercariae, and worm establishment were not affected by the radiolabeling. 35S was thus found useful for radiolabeling adult S. japonicum worms.

In a histopathological study of goats experimentally infected with Schistosoma bovis, the characteristics of the inflammatory response in the small intestine and liver related to tissue egg counts and fecal egg excretion were compared between goats at different time periods of primary infection and of primary infection followed by challenge. At early patency, coinciding with increasing egg excretion, the intestinal lamina propria showed numerous intact schistosome eggs devoid of any inflammatory reaction, whereas egg-associated inflammatory foci in the intestine were significantly few. Later in primary infection and after challenge, intestinal changes were marked by a granulomatous anti-egg response, with only a minor component of eggs lacking inflammatory change, and were consistent with a reduction of egg transfer into the gut wall. Hepatocellular necrosis with eosinophil infiltration was pronounced only during the early patent stage. The results indicate that the early cascade of fecal egg excretion in caprine schistosomosis bovis is aided by a low degree of tissue reactivity to eggs in the intestine. They also lend support to previous findings indicating that an anti-fecundity effect is operative after exposure to challenge in this parasitic infection in goats.

Experimental primary and challenge Schistosoma bovis infections were studied in West African Dwarf goats, using clinicopathological and parasitological parameters. The experiment included 44 goats divided into 4 groups of which group A received primary infection, group B received primary and challenge infection, group C received a challenge control infection, and group D included noninfected controls. Primary infection (wk 0) and challenge infection (wk 16) both comprised exposure to 1,000 cercariae per goat, and necropsies took place 16, 22 and 32 wk following primary infection. Clinicopathological effects were moderate in all infected groups. Egg excretion became gradually reduced following peak levels during early primary infection, and egg excretion increased only marginally following challenge infection in the primary- and challenge-infection group. Similarly, challenge infection of primary-infected goats did not result in an increase in tissue egg counts. Worm recovery and tissue egg counts in primary-infected goats remained comparable throughout the experiment, and although evidence was obtained for a delay in maturation, challenge worm establishment was comparable with challenge-control worm establishment. An anti-fecundity effect is thus an essential component of the regulatory response to both primary and challenge S. bovis infection in the goats. However, it was also shown that the intrauterine egg count is an unreliable parameter for fecundity assessments.

An optimized procedure for perfusion of pigs infected with Schistosoma japonicum was developed. The technique involves insertion of a perfusion influx tube into the thoracic descending aorta, clamping vessels to parts of the body which did not need to be perfused (the kidneys, hind legs, etc.) and placing a collection tube directly into the portal vein. In addition, the clamping technique allows for separate perfusion of the liver and intestinal veins. The perfusion medium was a sodium citrate buffer (40 degrees C) to which the vasodilator sodium nitroprusside was added. Furthermore, an experiment was conducted to investigate if the perfusion efficiency, measured by total worm recovery, could be increased if praziquantel was administered prior to perfusion. Twelve pigs were each infected with 1000 S. japonicum cercariae and their schistosomes were collected 11 weeks later by separate perfusion of the liver and intestinal veins. Six of these pigs were treated orally with praziquantel one hour before perfusion. In general, the vessels of the livers and intestines of all pigs were well perfused, judging by the resulting pale colour of the tissues. Worms from praziquantel treated pigs were collected within 5 min of perfusion as opposed to approximately 20 min in the non-treated pigs. More worms were collected from the livers of the praziquantel treated pigs, indicating a hepatic shift of schistosomes from the intestinal mesenteries. However, comparable numbers of worms were retained in the mesenteric veins following perfusion in the 2 groups, indicating that manual recovery of schistosomes from the intestinal mesenteries is necessary in addition to perfusion for obtaining the total worm counts. Another experiment was conducted to determine if the intensity and/or duration of infection had an effect on the number of worms collected by the perfusion technique. Seventy-two pigs were allocated into 3 groups of 24 pigs each, which were infected with either 100, 500 or 2000 cercariae per pig. The 3 groups were further divided into 4 subgroups of 6 pigs each which were perfused with our selective technique at 4, 11, 17 or 24 weeks post infection, respectively. All of the pigs received an oral praziquantel treatment prior to perfusion. The results indicated that increasing intensities and/or duration of infection resulted in trapping of schistosomes in intravascular inflammatory reactions which made it more difficult to collect the adult schistosomes by perfusion.

This study was undertaken to assess the suitability of Danish Landrace/Yorkshire (L/Y) crossbred pigs as experimental hosts of a Chinese mainland strain of Schistosoma japonicum. Pigs were exposed to 200, 500 or 1000 cercariae and parasite burdens were determined by perfusion after either 8 or 11 weeks. All pigs became infected with onset of faecal egg excretion 6 to 7 weeks following exposure to cercariae. The pattern of faecal egg excretion differed markedly among the individual animals. Gross hepatic pathological lesions of varying degrees were noted in all of the pigs. Schistosome worm recoveries ranged from 1.5-23.4% of the cercarial exposure dose. Most schistosome eggs recovered from the tissues, expressed as eggs/g tissue, were found in the rectum (91%), caecum (3.1%) and liver (5.1%). The results show that Danish L/Y pigs may serve as appropriate experimental final hosts of the Chinese mainland strain of S. japonicum.