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An abstract of a paper on various approaches to control parasites in livestock presented at the 22nd Symposium of the Nordic Committee for Veterinary Scientific Cooperation (NKVet) held in Helsinki, Finland from September 7-9, 2008 is presented.

Aim Climate change has the potential to have an impact on the distribution of ticks and tick-borne diseases. This paper identifies the changes in climate suitability for the tick Rhipicephalus (Boophilus) microplus in the Americas by analysing climate data for the period 1950–99. Location The model was applied to the American continent. Methods A model based on Environmental Niche Modelling was used on a gridded (0.5°) long-term (1950–99) climate data set. A map of the core range of the species was constructed, and areas where habitat suitability (HS) changes suddenly over short time periods were identified as regions of high sensitivity. Tendency of climate in the continent was evaluated and scenarios constructed for 2025 and 2050. Results Regions of high sensitivity included the southern USA, Mexico and western and central Argentina. Analysis of climate variables in these regions identified water vapour pressure deficit and evaporation as underlying the high sensitivity of habitat suitability in the USA and Mexico, and showed that episodes of high variability are linked to the El Niño Southern Oscillation. Projections of the tendency of HS as observed for the 1950–99 period point to an increase in this value in parts of the southern USA and in central Argentina, a finding that can be attributed to the progressive increase in minimum and yearly averaged temperatures. Conclusions Short-term changes in climate may drive the system into unstable situations with sudden changes in habitat suitability for the target tick in specific zones of the Americas. Results suggest an increased abiotic (climate) suitability for R. microplus in areas whose habitat is currently unsuitable for this species. [ABSTRACT FROM AUTHOR]

This study was conducted for the purpose of evaluating infection with the parasite Fasciola spp in the city of Mosul for the period from June 2020 to June 2022. The results showed that a total of 12.30% of cattle and sheep had Fasciola eggs in their feces, with a significant difference between cattle and sheep, and the infection was high in cattle 16%. The eggs of the Fasciola species are oval, brown to yellow in color, and have an operculum. There was no significant difference in the rate of infection with the Fasciola parasite and the sex of cattle and sheep. Regarding the relationship between the rate of infection and the age of the animals infected, there were no significant differences between the infection and the age groups of the examined sheep. Whereas there was a significant difference between the cattle whose age was less than one year, one to two years old and more than two years old. The results of the serological examination of 90 blood samples of cattle and sheep showed that the seroprevalence of Fasciola in both cattle and sheep was 22.22% and 8.88%, respectively, with no difference in the incidence of infection between all the examined cattle and sheep. [ABSTRACT FROM AUTHOR]

The low efficiency and profitability of animal production systems in tropical countries, along with the subsequent deterioration of the environment, has compelled the search for systems that maximize the productive and economic efficiency and the natural balance with the environment. For such reason, the objective of this paper is to review the main results of Latin America and the Caribbean with the use of silvopastoral system (SPSs) for milk and beef production and for the control of parasitism in cattle. SPSs offer high edible biomass availability, higher than 30 t DM ha-1year-1, of which the pasture represents 75-90 % and the tree foliage, 10-25 %. The diet shows a CP content of 11-16 % and an IVDMD of 510-630 g kg-1 DM and allows a milk production of 10-12 kg cow-1day-1 and between 3 000 and 16 000 kg ha-1year-1. For beef production, SPSs guarantee a weight gain between 0,42 and 1,10 kg animal-1day-1; while the production per hectare is between 500 and 1 340 kg year-1. In addition, SPSs propitiate the increase of the soil biota which accelerates dung decomposition, reducing gastrointestinal parasitism in the animals and the increase of the fauna associated that regulates the populations of ticks and vector insects. The need to transform degraded pasture systems as well as the crops of cultivated grasses in SPSs is emphasized; thus they improve the nutritional quality and balance of the diet for the animals, the efficiency in milk and beef production per hectare is optimized and a contribution is made to the control of parasite diseases in the herds. [ABSTRACT FROM AUTHOR]

Simple Summary: Endoparasites are a major problem in cattle farming worldwide, but their diffusion and abundance are poorly known in many low-income countries, where ruminants are mostly raised extensively. This study investigated the diffusion of gastrointestinal parasites in an area of central Ethiopia and identified the factors that are facilitating their presence. A total of 691 samples were analyzed using qualitative and quantitative tests to detect this presence and to estimate the burden from different groups of parasites. The influence of individual (age, sex and body condition) and environmental (agroecology and season) factors was statistically evaluated. The groups of parasites more prevalent in the investigated cattle population were gastro-intestinal strongyles (50%) and coccidian protozoa (36%), followed by cestodes (16%). Other parasites were sporadically found. The animals' body condition resulted in the most relevant risk factor, mainly for gastro-intestinal strongyles, since those with a poor body condition were associated with a higher prevalence of parasites. Environmental factors resulted, importantly, in influencing the diffusion of many groups of parasites, with the wet season being more favorable for parasite transmission. The results of this study contribute to a better understanding of the parasite dynamics in this specific context and suggest the use of a BCS for the implementation of targeted treatments for the most parasitized animals. Parasitic diseases are a major impediment to livestock production worldwide. However, knowledge about the epidemiology of gastrointestinal parasites in many low-income countries is still limited. An epidemiological survey on these parasites in traditionally reared cattle was performed in central Ethiopia (West Shewa Zone), from September 2019 to November 2021. Overall, 691 samples were analyzed qualitatively (flotation technique) and quantitatively (McMaster technique) to detect helminth eggs and Eimeria oocysts. Furthermore, coprocultures were conducted on pooled samples to identify the genera of gastrointestinal strongyles (GIS). The difference in prevalence according to agroecology, season, age, sex and body condition score (BCS) was investigated using univariable tests and through a multivariable logistic regression analysis, whereas abundance values were interpreted using a descriptive approach. The highest prevalence values were observed for GIS (50.2%) and Eimeria spp. (36.0%), whereas Moniezia spp. (16.3%), Strongyloides spp. (5.1%) and Schistosoma spp. (4.2%) showed lower values. Trichuris spp. and Toxocara vitulorum were sporadically found. A coproculture revealed that Haemonchus spp. (34.6%), Trichostrongylus spp. (25.9%) and Bunostomum spp. (19.1%) were the most frequent genera of GIS. A poor BCS was strongly associated with the occurrence of GIS, while seasonal variations were detected for Eimeria spp., GIS, Moniezia spp. and Schistosoma spp., with a higher prevalence and burden during the rainy season, and agroecology also strongly influenced different parasitic taxa. This present study increases the knowledge about the epidemiological features of gastrointestinal parasites in the context of a low-income country, suggesting a more tailored approach for their control. The use of a BCS as an indicator for the selective treatment of highly infested animals is supported by our findings, introducing a possible way to prevent anthelmintic resistance in areas where basic diagnostic services are rarely used by farmers. [ABSTRACT FROM AUTHOR]

Rhipicephalus microplus is one of the most important ectoparasites of cattle in tropical and subtropical regions. In ticks collected from cattle the pathogens Babesia bovis, Anaplasma spp. and Ehrlichia spp. can be detected. Here, we report the first detection of the pathogen Anaplasma phagocytophilum in Madagascar from ticks infesting cattle. Furthermore, we report for the first time Anaplasma ovis, Ehrlichia canis, Ehrlichia ewingii and Ehrlichia muris in both R. microplus and in Madagascar. We show no correlation between the detection of B. bovis, Ehrlichia spp. and Anaplasma spp. DNA within the same tick. Previous reports have demonstrated strong interactions between A. marginale, A. centrale and A. ovis in the same tick, as well between these pathogens and A. phagocytophilum. A strong correlation also existed between the occurrences of Ehrlichia species within the same tick. Our findings suggest that R. microplus ticks are potential vectors and reservoirs of many tick-borne diseases of cattle. [ABSTRACT FROM AUTHOR]

Onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, is a neglected tropical disease mainly of sub-Saharan Africa. Worldwide, an estimated 20.9 million individuals live with infection and a further 205 million are at risk of disease. Current control methods rely on mass drug administration of ivermectin to kill microfilariae and inhibit female worm fecundity. The identification and development of efficacious vaccines as complementary preventive tools to support ongoing elimination efforts are therefore an important objective of onchocerciasis research. We evaluated the protective effects of co-administering leading O. volvulus-derived recombinant vaccine candidates (Ov-103 and Ov-RAL-2) with subsequent natural exposure to the closely related cattle parasite Onchocerca ochengi. Over a 24-month exposure period, vaccinated calves (n = 11) were shown to acquire infection and microfilaridermia at a significantly lower rate compared to unvaccinated control animals (n = 10). Furthermore, adult female worm burdens were negatively correlated with anti-Ov-103 and Ov-RAL-2 IgG1 and IgG2 responses. Peptide arrays identified several Ov-103 and Ov-RAL-2-specific epitopes homologous to those identified as human B-cell and helper T-cell epitope candidates and by naturally-infected human subjects in previous studies. Overall, this study demonstrates co-administration of Ov-103 and Ov-RAL-2 with Montanide™ ISA 206 VG is highly immunogenic in cattle, conferring partial protection against natural challenge with O. ochengi. The strong, antigen-specific IgG1 and IgG2 responses associated with vaccine-induced protection are highly suggestive of a mixed Th1/Th2 associated antibody responses. Collectively, this evidence suggests vaccine formulations for human onchocerciasis should aim to elicit similarly balanced Th1/Th2 immune responses. [ABSTRACT FROM AUTHOR]

Background: The current review article outlines current findings in literature from undertaken studies and review articles on the plant Elephantorrhiza elephantine from the past 20 years to date. The information presented in this article will include the following aspects of the plant. The plant description and taxomony, ethnomedical uses, phytochemistry and pharmacology of Elephantorrhiza elephantine. The article looks to discuss existing hurdles in research found on this plant and how to integrate any previous research with what is currently done in research on the plant. It aims on guiding the path of future research direction on the plant Elephantorrhiza elephantine. Methods: A total of 40 articles were selected and read through. The articles selected had included literature publications with the keywords such as; Elephantorrhiza elephantine, plant description, taxonomic of the plant, ethno medicinal usages, phytochemicals, pharmacological properties and plant toxicity, which were published between the years 2000 - 2021. There were 32 articles relevant for this review article and 2 dissertation that were written between the criteria of years. Results: The ethomedicinal uses of Elephantorrhiza elephantine have been investigated by various authors on the anti-microbial activities, anti-inflammatory, anticancer and in ethnoveterinary medicine on how the plant provides relief to individuals with illnesses/disease through its traditional uses. These studies have been conducted on both animals and humans. The experiments performed used the crude extract derived from parts of the plant such as the roots and leaves. These plant parts have phytochemical compounds that are extracted using varying polar solvents. In the animal studies, acetone extracts of E. elephantine roots demonstrated significant activity against a tick-borne disease in cattle livestock and parasite worms in goats. In humans, the dried leaf extracts of E. elephantine was also subjected to various polar solvents and water, investigated for phytochemical content, antioxidant, anti-inflammatory, anti-diabetic and cytotoxic activities, using standard methods. It was reported that the ethanol extract yielded the highest phytochemical content. Conclusion: The gap in knowledge has narrowed on medicinal plants effects of healing properties. This lead by extensive research carried out trying to understand the benefits of traditional medication and why majority of the population uses it as they primary healthcare choice. Investigating the mechanism of action of E. elephantine on its antimicrobial, anti-diabetic, antimalarial, anti-inflammatory and wound healing could lead to an enhanced understanding on the medicinal properties of the plant extracts and a commercialisation of a product in future. [ABSTRACT FROM AUTHOR]

Theileria parva (T. parva) is a protozoan parasite that causes East Coast fever (ECF). The disease is endemic in Burundi and is a major constraint to livestock development. In this study, the parasite prevalence in cattle in six regions namely; Northern, Southern, Eastern, Western, Central and North Eastern was estimated. Furthermore, the sequence diversity of p67, Tp1 and Tp2 genes was assessed coupled with the population genetic structure of T. parva using five satellite markers. The prevalence of ECF was 30% (332/1109) on microscopy, 60% (860/1431) on ELISA and 79% (158/200) on p104 gene PCR. Phylogenetic analysis of p67 gene revealed that only allele 1 was present in the field samples. Furthermore, phylogenetic analysis of Tp1 and Tp2 showed that the majority of samples clustered with Muguga, Kiambu and Serengeti and shared similar epitopes. On the other hand, genetic analysis revealed that field samples shared only two alleles with Muguga Cocktail. The populations from the different regions indicated low genetic differentiation (FST = 0.047) coupled with linkage disequilibrium and non-panmixia. A low to moderate genetic differentiation (FST = 0.065) was also observed between samples and Muguga cocktail. In conclusion, the data presented revealed the presence of a parasite population that shared similar epitopes with Muguga Cocktail and was moderately genetically differentiated from it. Thus, use of Muguga Cocktail vaccine in Burundi is likely to confer protection against T. parva in field challenge trials. [ABSTRACT FROM AUTHOR]

In this paper, a tick sampling method developed by authors was employed with the purpose of saving acaricides and decreasing environmental pollution by the use of acaricidal dip control bathing bovines in relation to a critical number of estimated ticks. Twenty-six Jersey cows in production were sampled. The selected sampling regions were: rear leg, udder, perinea and tail. Samplings were done from 7 to 8 am, and female tick standard size pattern was 6 mm or longer. Every two weeks approximately, samplings and acaricidal baths were done (13 samplings in total). Only cows with 10 or more ticks received acaricidal baths. Results showed that the procedure allows saving 50% of acaricides. [ABSTRACT FROM AUTHOR]

Neospora caninum, a cyst-forming apicomplexan parasite, is a leading cause of neuromuscular diseases in dogs as well as fetal abortion in cattle worldwide. The importance of the domestic and sylvatic life cycles of Neospora, and the role of vertical transmission in the expansion and transmission of infection in cattle, is not sufficiently understood. To elucidate the population genomics of Neospora, we genotyped 50 isolates collected worldwide from a wide range of hosts using 19 linked and unlinked genetic markers. Phylogenetic analysis and genetic distance indices resolved a single genotype of N. caninum. Whole-genome sequencing of 7 isolates from 2 different continents identified high linkage disequilibrium, significant structural variation, but only limited polymorphism genome-wide, with only 5,766 biallelic single nucleotide polymorphisms (SNPs) total. Greater than half of these SNPs (~3,000) clustered into 6 distinct haploblocks and each block possessed limited allelic diversity (with only 4 to 6 haplotypes resolved at each cluster). Importantly, the alleles at each haploblock had independently segregated across the strains sequenced, supporting a unisexual expansionmodel that is mosaic at 6 genomic blocks. Integrating seroprevalence data from African cattle, our data support a global selective sweep of a highly inbred livestock pathogen that originated within European dairy stock and expanded transcontinentally via unisexual mating and vertical transmission very recently, likely the result of human activities, including recurrent migration, domestication, and breed development of bovid and canid hosts within similar proximities. [ABSTRACT FROM AUTHOR]

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Background: Identification of species-specific trypanosome molecules is important for laboratory- and field-based research into epidemiology and disease diagnosis. Although Trypanosoma congolense is the most important trypanosome pathogen of cattle in Africa, no species-specific molecules found in infective bloodstream forms (BSF) of the parasites have been identified, thus limiting development of diagnostic tests. Methods: Immuno-mass spectrometric methods were used to identify a protein that is recognized by a T. congolense-specific monoclonal antibody (mAb) Tc6/42.6.4. The identified molecule was expressed as a recombinant protein in E. coli and was tested in several immunoassays for its ability to interact with the mAb. The three dimensional structure of the protein was modeled and compared to crystal- and NMR-structures of the homologous proteins from T. cruzi and T. brucei respectively, in order to examine structural differences leading to the different immunoreactivity of the T. congolense molecule. Enzyme-linked immunosorbent assays (ELISA) were used to measure antibodies produced by trypanosome-infected African cattle in order to assess the potential for use of T. congolense calflagin in a serodiagnostic assay. Results: The antigen recognized by the T. congolense-specific mAb Tc6/42.6.4 was identified as a flagellar calcium-binding protein, calflagin. The recombinant molecule showed immunoreactivity with the T. congolense-specific mAb confirming that it is the cognate antigen. Immunofluorescence experiments revealed that Ca2+ modulated the localization of the calflagin molecule in trypanosomes. Structural modelling and comparison with calflagin homologues from other trypanosomatids revealed four non-conserved regions on the surface of the T. congolense molecule that due to differences in surface chemistry and structural topography may form species-specific epitopes. ELISAs using the recombinant calflagin as antigen to detect antibodies in trypanosome-infected cattle showed that the majority of cattle had antibody responses. Area under the Receiver-Operating Characteristic (ROC) curves, associated with host IgG and IgM, were calculated to be 0.623 and 0.709 respectively, indicating a positive correlation between trypanosome infection and the presence of anti-calflagin antibodies. Conclusions: While calflagin is conserved among different species of African trypanosomes, our results show that T. congolense calflagin possesses unique epitopes that differentiate this protein from homologues in other trypanosome species. MAb Tc6/42.6.4 has clear utility as a laboratory tool for identifying T. congolense. T. congolense calflagin has potential as a serodiagnostic antigen and should be explored further for its utility in antigen-detection assays for diagnosis of cattle infections. [ABSTRACT FROM AUTHOR]

During our examination performed in the period from 2010 to 2012, we collected ticks from 52 flocks of sheep and 38 goat flocks. Ticks infestation occured in 15.97% (214/1340) of sheep and 16.93% (107/632) of goats. The result showed the presence of Ixodes ricinus, Rhipicephalus sanguineus, R. bursa, Dermacentor marginatus, D. pictus, Haemaphysalis punctata and Ha. inermis. Additional to determination of tick species during the research, the sex ratio and the monthly influence of microclimate conditions (temperature, relative humidity and precipitation quantity) on the dynamics of populations of ticks were followed. Obtained results indicate the importance of the impact of climatic factors on the population dynamics of some species of ticks as well as the dynamics and abundance of different sexes within established species of ticks. [ABSTRACT FROM AUTHOR]

Background: Schistosoma japonicum causes major public health problems in China and the Philippines; this parasite, which is transmitted by freshwater snails of the species Oncomelania hupensis, causes the disease intestinal schistosomiasis in humans and cattle. Researchers working on Schistosoma in Africa have described the relationship between the parasites and their snail intermediate hosts as coevolved or even as an evolutionary arms race. In the present study this hypothesis of coevolution is evaluated for S. japonicum and O. hupensis. The origins and radiation of the snails and the parasite across China, and the taxonomic validity of the sub-species of O. hupensis, are also assessed. Methodology/Principal Findings: The findings provide no evidence for coevolution between S. japonicum and O. hupensis, and the phylogeographical analysis suggests a heterochronous radiation of the parasites and snails in response to different palaeogeographical and climatic triggers. The results are consistent with a hypothesis of East to West colonisation of China by Oncomelania with a re-invasion of Japan by O. hupensis from China. The Taiwan population of S. japonicum appears to be recently established in comparison with mainland Chinese populations. Conclusions/Significance: The snail and parasite populations of the western mountain region of China (Yunnan and Sichuan) appear to have been isolated from Southeast Asian populations since the Pleistocene; this has implications for road and rail links being constructed in the region, which will breach biogeographical barriers between China and Southeast Asia. The results also have implications for the spread of S. japonicum. In the absence of coevolution, the parasite may more readily colonise new snail populations to which it is not locally adapted, or even new intermediate host species; this can facilitate its dispersal into new areas. Additional work is required to assess further the risk of spread of S. japonicum. [ABSTRACT FROM AUTHOR]

Ticks and tick-borne diseases (TBDs) affect the productivity of bovines in tropical and subtropical regions of the world, leading to a significant adverse impact on the livelihoods of resource-poor farming communities. Globally, four main TBDs, namely anaplasmosis, babesiosis, theileriosis, and cowdriosis (heartwater) affect bovines, and the former three are of major economic importance in bovines in Pakistan. Given that the livestock sector has become an integral part of Pakistan's economy and a large number of dairy cattle are being imported into the country, in order to meet an increasing demand of milk and milk products, it is timely to review current status of bovine TBDs in Pakistan and to identify gaps in the knowledge of TBDs and their control. Although there has been a recent increase in the number of studies of TBDs in this country, information on their prevalence, distribution, tick vectors, and control is limited. This article provides a brief background on key bovine TBDs and ticks and reviews the current status of bovine TBDs in Pakistan to identify gaps in knowledge and understanding of these diseases, propose areas for future research and draw attention to the need for improved tools for the diagnosis and control of TBDs in this country. [ABSTRACT FROM AUTHOR]

Control of helminth infections is a major task in livestock production to prevent health constraints and economic losses. However, resistance to established anthelmintic substances already impedes effective anthelmintic treatment in many regions worldwide. Thus, there is an obvious need for sensitive and reliable methods to assess the resistance status of at least the most important nematode populations. Several single nucleotide polymorphisms (SNPs) in the β-tubulin isotype 1 gene of various nematodes correlate with resistance to benzimidazoles (BZ), a major anthelmintic class. Here we describe the full-length β-tubulin isotype 1 and 2 and α-tubulin coding sequences of the cattle nematode Ostertagia ostertagi. Additionally, the Cooperia oncophora α-tubulin coding sequence was identified. Phylogenetic maximum-likelihood analysis revealed that both isotype 1 and 2 are orthologs to the Caenorhabditis elegans ben-1 gene which is also associated with BZ resistance upon mutation. In contrast, a Trichuris trichiura cDNA, postulated to be β-tubulin isotype 1 involved in BZ resistance in this human parasite, turned out to be closely related to C. elegans β-tubulins tbb-4 and mec-7 and would therefore represent the first non-ben-1-like β-tubulin to be under selection through treatment with BZs. A pyrosequencing assay was established to detect BZ resistance associated SNPs in β-tubulin isotype 1 codons 167, 198 and 200 of C. oncophora and O. ostertagi. PCR-fragments representing either of the two alleles were combined in defined ratios to evaluate the pyrosequencing assay. The correlation between the given and the measured allele frequencies of the respective SNPs was very high. Subsequently laboratory isolates and field populations with known resistance status were analyzed. With the exception of codon 167 in Cooperia, increases of resistance associated alleles were detected for all codons in at least one of the phenotypically resistant population. Pyrosequencing provides a fast, inexpensive and sensitive alternative to conventional resistance detection methods. [ABSTRACT FROM AUTHOR]

The objectives of this study were: (1) to determine the prevalence and factors associated with Rhipicephalus microplus, resistant to cypermethrin and amitraz, from cattle farms in Veracruz, Mexico, and (2) to determine in vitro mortality percentages of field populations of R. rnicroplus exposed to discriminating doses (DD) of cypermethrin and amitraz. Fifty-three populations of R. rnicroplus were tested by bioassays using DD of cypermethrin (0.05%) and amitraz (0.0002%). The prevalence of cattle farms with R. microplus ticks that were resistant to cypermethrin and amitraz, and co-resistant to both acaricides, was 90.6, 54.7, and 47.2%, respectively. The level of cypermethrin resistance, measured as a survival percentage, was higher as compared to amitraz. Cattle farms with <50 animals (odds ratio [OR] = 3.84, 95% confidence interval [CI] = 1.07-13.70, P = 0.038) and a stocking density of > 1 animal unit per ha (AU/ha) (OR = 4.21, 95% CI = 1.0-17.71, P - 0.050) had a higher probability to develop R. microplus tick populations co- resistant to both acaricides. In conclusion, there is a high prevalence of R. microplus populations on cattle farms in Veracruz, Mexico that are both resistant to cypermethrin and amitraz and co-resistant to both acaricides. The level of cypermethrin resistance is critical, and the exposition variables of -<50 cattle and a stocking density of > 1 AU/ha were factors associated with R. microplus co-resistant to both acaricides. [ABSTRACT FROM AUTHOR]

We describe here a rapid and efficient method for the targeted isolation of specific members of gene families without the need for cloning. Using this strategy we isolated full length cDNAs for eight putative G-protein coupled neurotransmitter receptors (GPCnR) from the cattle tick Rhipicephalus (Boophilus) microplus. Gene specific degenerate primers were designed using aligned amino acid sequences of similar receptor types from several insect and arachnid species. These primers were used to amplify and sequence a section of the target gene. Rapid amplification of cDNA ends (RACE) PCR was used to generate full length cDNA sequences. Phylogenetic analysis placed 7 of these sequences into Class A Gprotein coupled receptors (GPCR) (Rm•α2AOR, Rm•β2AOR, Rm•Dop1R, Rm•Dop2R, Rm•INDR, Rm•5-HT7R and Rm•mAchR), and one into Class C GPCR (Rm•GABABR). Of the 7 Class A sequences, only Rm•mAchR is not a member of the biogenic amine receptor family. The isolation of these putative receptor sequences provides an opportunity to gain an understanding of acaricide resistance mechanisms such as amitraz resistance and might suggest possibilities for the development of new acaricides. [ABSTRACT FROM AUTHOR]

Epizootic haemorrhagic disease virus (EHDV) infects wild ruminants, causing a frequently fatal haemorrhagic disease. However, it can also cause bluetongue-like disease in cattle, involving significant levels of morbidity and mortality, highlighting a need for more rapid and reliable diagnostic assays. EHDV outer-capsid protein VP2 (encoded by genomesegment 2 [Seg-2]) is highly variable and represents the primary target for neutralising antibodies generated by the mammalian host. Consequently VP2 is also the primary determinant of virus "serotype", as identified in virus neutralisation tests (VNT). Although previous reports have indicated eight to ten EHDV serotypes, recent serological comparisons and molecular analyses of Seg-2 indicate only seven EHDV "types". Oligonucleotide primers were developed targeting Seg-2, for use in conventional RT-PCR assays to detect and identify these seven types. These assays, which are more rapid and sensitive, still show complete agreement with VNT and were used to identify recent EHDV isolates from the Mediterranean region and North America. [ABSTRACT FROM AUTHOR]

The transmission dynamics of Schistosoma japonicum remain poorly understood, as over forty species of mammals are suspected of serving as reservoir hosts. However, knowledge of the population genetic structure and of the full-sibship structuring of parasites at two larval stages will be useful in defining and tracking the transmission pattern between intermediate and definitive hosts. S. japonicum larvae were therefore collected in three marshland and three hilly villages in Anhui Province of China across three time points: April and September-October 2006, and April 2007, and then genotyped with six microsatellite markers. Results from the population genetic and sibling relationship analyses of the parasites across two larval stages demonstrated that, within the marshland, parasites from cattle showed higher genetic diversity than from other species; whereas within the hilly region, parasites from dogs and humans displayed higher genetic diversity than those from rodents. Both the extent of gene flow and the estimated proportion of full-sib relationships of parasites between two larval stages indicated that the cercariae identified within intermediate hosts in the marshlands mostly came from cattle, whereas in the hilly areas, they were varied between villages, coming primarily from rodents, dogs or humans. Such results suggest a different transmission process within the hilly region from within the marshlands. Moreover, this is the first time that the sibling relationship analysis was applied to the transmission dynamics for S. japonicum. [ABSTRACT FROM AUTHOR]

Background: Studies on the epidemiology of African Animal Trypanosomiasis (AAT) rarely consider the spatial dimension of disease prevalence. This problem is confounded by use of parasitological diagnostic methods of low sensitivity in field surveys. Here we report a study combining highly sensitive and species specific molecular diagnostic methods, and Geographical information system (GIS) for spatial analysis of trypanosome infection patterns, to better understand its epidemiology. Blood samples from 44 and 59 animals randomly selected from Teso and Suba districts respectively were screened for trypanosomes using PCR diagnostic assays. Spatial distribution of the positive cases was mapped and average nearest neighbour analysis used to determine the spatial pattern of trypanosome cases detected. Findings: Trypanosome prevalence of 41% and 29% in Suba and Teso districts respectively was observed. T. vivax infections were most prevalent in both areas. Higher proportions of T. brucei infections (12%) were observed in Suba, a known sleeping sickness foci compared with 2% in Teso. Average nearest neighbour analysis showed the pattern of trypanosome infections as random. An overlay with tsetse maps showed cases lying outside the tsetse infested areas, mostly being cases of T. vivax which is known to be transmitted both biologically by tsetse and mechanically by biting flies. Conclusion: These findings suggest a need to design control strategies that target not just the biological vector tsetse, but also the parasite in cattle in order to clear the possibly mechanically transmitted T. vivax infections. There is need to also review the accuracy of available tsetse maps. [ABSTRACT FROM AUTHOR]

The peri-parturient period is crucial for controlling worms as the acquired immunity of ewes is disrupted, resulting in an increase in faecal worm egg counts. Two hypotheses were tested in this experiment — that ewes bred for worm resistance would have lower faecal worm egg counts than unselected control ewes, during late pregnancy and lactation, under similar but separate grazing areas; and also that numbers of infective nematode larvae would be lower on pastures grazed by resistant ewes than pastures grazed by unselected control ewes. Faecal samples were collected from resistant and unselected ewes in late pregnancy and early lactation, during the winter rainfall season, and analysed for numbers of Trichostrongylus colubriformis and Teladorsagia circumcincta. Pasture samples were taken 1 week before and 7 weeks after lambing started and analysed for infective larvae. In all sheep, worm egg counts rose 2 weeks prior to lambing and continued into lactation. Worm egg counts were significantly lower in the resistant ewes from 1 week before lambing to 2 weeks after lambing. There were no differences in egg counts between single- and twin-bearing ewes in the resistant line. However, twin-bearing control ewes had significantly higher egg counts than single-bearing control ewes. Following lactation, plots grazed by resistant ewes had substantially less contamination with T. colubriformis larvae, but there were no differences in numbers of T. circumcincta larvae. Our results demonstrate that sheep bred for worm resistance has lower worm burdens during the peri-parturient phase and that lambs born to resistant ewes face a lower larval challenge during their introduction to grazing. In our environment, selection for low worm egg counts has produced sheep highly resistant to T. colubriformis, but has had less impact on resistance towards T. circumcincta. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAb) were produced against midgut membrane (GM) antigens of Boophilus microplus. The isotypes of these mAb were established and their specificity characterized using double diffusion and Western blotting. GM antigens solubilized by Triton X-100 were precipitated by mAb QU13, and the precipitate was then injected into cattle to test for the presence of protective antigens. Vaccinated cattle challenged with 10-day-old larval ticks showed evidence of protection with a 62% reduction in eggs produced by ticks from vaccinated cattle compared to tick eggs from control cattle. In a second vaccine-challenge experiment, the dose of precipitate was increased and >99% protection was provided to these vaccinated cattle following challenge (calculated from tick egg weights compared to the control group). The solubilized antigen(s) precipitated by QU13 were subjected to SDS-PAGE separation and the calculated sizes of these molecules were >200,000, 80,000, 74,000, 62,000, 57,000 and <30,000 MW. [ABSTRACT FROM AUTHOR]

Background: Cattle are commonly infected with the microsporidian parasite Enterocytozoon bieneusi. Sequence characterization of E. bieneusi in these animals at the ribosomal internal transcribed spacer (ITS) locus had identified I, J and BEB4 as the dominant genotypes. However, current studies on E. bieneusi in dairy cattle are mostly on infection rates and genotype distribution. This study aims to examine the intragenotypic diversity within dominant E. bieneusi genotypes in pre-weaned dairy calves in Shanghai, China. Methods: Enterocytozoon bieneusi genotypes and subtypes were identified by PCR sequence analysis of ITS and multilocus sequence typing (MLST), based on material from farms. Chi-square test was used to examine differences in E. bieneusi infection rates between farms or age groups. Results: The overall infection rate of E. bieneusi was 26.5% (214/809), ranging from 12.6% (Farm 5) to 38.5% (Farm 4). Infection rates increased with age during early life, with the peak infection rate (43.0%; 43/100) occurring at six weeks. Four genotypes were present, including J (n = 145, 67.8%), BEB4 (n = 59, 27.6%), CHN4 (n = 4, 1.9%) and CHN15 (n = 1, 0.5%), with the former two belonging to Group 2 and the latter two belonging to Group 1. Differences were detected in the distribution of the dominant genotypes J and BEB4 among five study farms. Altogether, 10 multilocus genotypes (MLGs) were identified in the two dominant ITS genotypes, including MLG-J1 to MLG-J8 of genotype J and MLG-B1 to MLG-B2 of genotype BEB4. MLG-B1 and MLG-B2 were recovered in Farms 1, 2 and 5, whereas MLG-J1 to MLG-J5 and MLG-J6 to MLG-J8 were found in Farms 3 and 4, respectively. Conclusions: There is extensive genetic heterogeneity within the dominant E. bieneusi genotypes J and BEB4 in dairy calves in Shanghai, China, and MLST should be used in molecular epidemiological studies of E. bieneusi in cattle. [ABSTRACT FROM AUTHOR]