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Background In slaughterhouse, veterinarians responsible for meat inspection are often confronted with abnormalities in carcasses, not only in pigs but in all livestock species. In 2017, a veterinarian responsible for meat inspection in a slaughterhouse in Styria, Austria, observed gluteal muscles infiltrated by fat and muscle tissue obviously being replaced by fat in two different slaughter pigs. These muscles were sent for further diagnostics to the University Clinic for Swine. Results The two muscle samples were investigated histopathologically and diagnosed with fatty muscular dystrophy. The results of routine histopathology were confirmed by dystrophin-specific immunohistochemistry. Sex of the two affected animals was determined retrospectively using a PCR-based protocol and resulted in one male and one female pig. A survey to determine the prevalence of fatty muscular disorders of pork revealed that this phenomenon gets frequently observed in Styria, but also occurs in Upper Austria and Lower Austria. Mostly gluteal and lumbal muscles were affected and approximately 20–40% of the affected muscles were replaced by fat. Conclusions Fatty muscular dystrophy or muscular steatosis, as it was sometimes called in early literature, seems not to be an uncommon and rare event and is known to have several different causes. As it was detected in both sexes, our observations are different to the described case in Japan, where only one male individual was affected. To avoid further increase of such cases (fatty muscular dystrophy), it would be useful to clarify the cause. First, whether the cause is environmental or genetic, and in case it is genetic it would be key to disentangle the underlying genomic architecture. Having causal variants described—one could think about integrating this information (depending on the mode of inheritance and the number of loci involved) in the breeding program of pigs. Furthermore, the proportion of non-Austrian pig genetics used for commercial pig production in Austria should be reviewed in order to be able to make reliable statements about the spread of the disease not only in Austrian pig breeds, but also in pig breeds worldwide.

Escherichia (E.) coli is the main causative pathogen of neonatal and post-weaning diarrhea and edema disease in swine production. There is a significant health concern due to an increasing number of human infections associated with food and/or environmental-borne pathogenic and multidrug-resistant E. coli worldwide. Monitoring the presence of pathogenic and antimicrobial-resistant E. coli isolates is essential for sustainable disease management in livestock and human medicine. A total of 102 E. coli isolates of diseased pigs were characterized by antimicrobial and biocide susceptibility testing. Antimicrobial resistance genes, including mobile colistin resistance genes, were analyzed by PCR and DNA sequencing.&nbsp, The quinolone resistance-determining regions of gyrA and parC in ciprofloxacin-resistant isolates were analyzed. Clonal relatedness was investigated by two-locus sequence typing (CH clonotyping). Phylotyping was performed by the Clermont multiplex PCR method. Virulence determinants were analyzed by customized DNA-based microarray technology developed in this study for fast and economic molecular multiplex typing. Thirty-five isolates were selected for whole-genome sequence-based analysis. Most isolates were resistant to ampicillin and tetracycline. Twenty-one isolates displayed an ESBL phenotype and one isolate an AmpC β-lactamase-producing phenotype. Three isolates had elevated colistin minimal inhibitory concentrations and carried the mcr-1 gene. Thirty-seven isolates displayed a multi-drug resistance phenotype. The most predominant β-lactamase gene classes were blaTEM-1 (56%) and blaCTX-M-1 (13.71%). Mutations in QRDR were observed in 14 ciprofloxacin-resistant isolates. CH clonotyping divided all isolates into 51 CH clonotypes. The majority of isolates belonged to phylogroup A. Sixty-four isolates could be assigned to defined pathotypes wherefrom UPEC was predominant. WGS revealed that the most predominant sequence type was ST100, followed by ST10. ST131 was detected twice in our analysis. This study highlights the importance of monitoring antimicrobial resistance and virulence properties of porcine E. coli isolates. This can be achieved by applying reliable, fast, economic and easy to perform technologies such as DNA-based microarray typing. The presence of high-risk pathogenic multi-drug resistant zoonotic clones, as well as those that are resistant to critically important antibiotics for humans, can pose a risk to public health. Improved protocols may be developed in swine farms for preventing infections, as well as the maintenance and distribution of the causative isolates.

This pilot study aimed to investigate stable flies from Austrian pig farms for the presence of defined swine pathogens, such as porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus 2 (PCV2), hemotrophic mycoplasmas in ingested blood and/or body parts and bacteria on the surface of the flies. Furthermore, the use of stable flies as a diagnostic matrix for the detection of pathogens in the ingested pig blood should be investigated. In total, 69 different microorganisms could be found on the surface of tested S. calcitrans from 20 different pig farms. Escherichia coli was the most common bacterium and could be found on flies from seven farms. In seven farms, hemotrophic mycoplasmas were detected in stable flies. PRRSV could not be found in any of the samples of these 20 farms but PCV2 was detected in six farms. Whether the stable fly can be used as a matrix to monitor the health status cannot be accurately determined through this study, especially in regard to PRRSV. Nevertheless, it might be possible to use the stable fly as diagnostic material for defined pathogens like Mycoplasma suis and PCV2.

Due to various challenges in diagnosing chlamydiosis in pigs, antibiotic treatment is usually performed before any molecular or antibiotic susceptibility testing. This could increase the occurrence of tetracycline-resistant Chlamydia (C.) suis isolates in the affected pig population and potentiate the reoccurrence of clinical signs. Here, we present a case of an Austrian pig farm, where tetracycline resistant and sensitive C. suis isolates were isolated from four finishers with conjunctivitis. On herd-level, 10% of the finishers suffered from severe conjunctivitis and sows showed a high percentage of irregular return to estrus. Subsequent treatment of whole-herd using oxytetracycline led to a significant reduction of clinical signs. Retrospective antibiotic susceptibility testing revealed tetracycline resistance and decreased susceptibility to doxycycline in half of the ocular C. suis isolates, and all isolates were able to partially recover following a single-dose tetracycline treatment in vitro. These findings were later confirmed in vivo, when all former clinical signs recurred three months later. This case report raises awareness of tetracycline resistance in C. suis and emphasizes the importance of preventative selection of tetracycline resistant C. suis isolates.

A sperm-driven micromotor is presented as a targeted drug delivery system, which is appealing to potentially treat diseases in the female reproductive tract. This system is demonstrated to be an efficient drug delivery vehicle by first loading a motile sperm cell with an anticancer drug (doxorubicin hydrochloride), guiding it magnetically, to an in vitro cultured tumor spheroid, and finally freeing the sperm cell to deliver the drug locally. The sperm release mechanism is designed to liberate the sperm when the biohybrid micromotor hits the tumor walls, allowing it to swim into the tumor and deliver the drug through the sperm-cancer cell membrane fusion. In our experiments, the sperm cells exhibited a high drug encapsulation capability and drug carrying stability, conveniently minimizing toxic side effects and unwanted drug accumulation in healthy tissues. Overall, sperm cells are excellent candidates to operate in physiological environments, as they neither express pathogenic proteins nor proliferate to form undesirable colonies, unlike other cells or microorganisms. This sperm-hybrid micromotor is a biocompatible platform with potential application in gynecological healthcare, treating or detecting cancer or other diseases in the female reproductive system.

Using ceftiofur during the first days of life is a common preventative strategy against several bacterial diseases in pig production. This study aimed to evaluate short- and long-term effects of early use of ceftiofur on the fecal microbiota development in suckling and growing pigs. Sixty-four piglets from eight litters were assigned to the antibiotic (AB, n = 32) or control group (control, n = 32). Twelve hours postpartum (day 0) AB piglets received an intramuscular injection of ceftiofur (5.0 mg/kg body weight) or a placebo. DNA was extracted from fecal samples collected on days 0, 12, 28, and 97 for deep-sequencing of the 16S rRNA gene. The AB administration disturbed the maturational changes in the fecal microbiome, whereby effects were sex-specific. Sex-related differences in AB metabolism in females and males may have caused these diverging AB-effects on the fecal microbiota. Especially the loss of bacterial diversity and of certain taxa in female AB pigs may have contributed to the decreased body weight of these females on day 97 of life. Taken together, this study showed that an AB injection with ceftiofur 12 h postpartum markedly affected the successional changes in the fecal microbiota composition in male and female pigs, with long-term consequences for host performance.

The novel pestivirus species known as lateral-shaking inducing neuro-degenerative agent (LINDA) virus emerged in 2015 in a piglet-producing farm in Austria. Affected piglets showed strong congenital tremor as a result of severe lesions in the central nervous system. Here, we report the results of a controlled animal infection experiment. Post-weaning piglets were infected with LINDA to determine the susceptibility of pigs, the clinical consequences of infection and the humoral immune response against LINDA. No clinically overt disease signs were observed in the piglets. Viremia was hardly detectable, but LINDA was present in the spleen and several lymphatic organs until the end of the experiment on day 28 post-infection. Oronasal virus shedding together with the infection of one sentinel animal provided additional evidence for the successful replication and spread of LINDA in the piglets. Starting on day 14 post-infection, all infected animals showed a strong humoral immune response with high titers of neutralizing antibodies against LINDA. No cross-neutralizing activity of these sera with other pestiviral species was observed. According to these data, following postnatal infection, LINDA is a rather benign virus that can be controlled by the pig&rsquo, s immune system. However, further studies are needed to investigate the effects of LINDA on the fetus after intrauterine infection.

A case of generalized exudative epidermitis (EE) is described, which occurred in a very small piglet producing farm in Austria. The antimicrobial treatment prescribed by the herd veterinarian did not improve the clinical problem. Therefore, the University Clinic for Swine intervened in the case. Lab investigations were initiated in which Staphylococcus hyicus (SH) and Staphylococcus aureus (SA), both methicillin-resistant and susceptible strains, could be isolated from the skin of affected piglets. Poor hygiene and management practices were identified as predisposing factors on site. Adaptation of antimicrobial treatment according to results of the in vitro susceptibility testing and the implementation of proper hygiene measures resolved the clinical problem. Here, we describe a fatal coinfection of SH and SA in suckling piglets.

Previous studies on the storability of porcine blood for bloodstain pattern analysis (BPA) focused on abattoir blood only and did not include measurements of viscoelasticity. Although known to provoke echinocyte formation, EDTA is widely used for BPA issues. We compared ageing samples taken from live pigs with abattoir blood and detected considerable differences in hematocrit (HCT), total protein and shear viscosity that even worsened with time. Upon storage, high shear viscosity continuously increased, resulting in a partial loss of the typical shear thinning property of blood. Furthermore, we explored CPDA-1, the gold standard in preserving red blood cells (RBCs), for storage of forensic samples. We found it to be a superior choice for anticoagulation, as the rise of high shear viscosity was attenuated compared to EDTA. When performing oscillation measurements, we found a sudden change of viscoelasticity of blood after 22 days, providing a cut-off for storage time. To highlight the importance of hematological and hemorheological changes upon cold storage, we performed simple drip pattern experiments. These tests revealed a tendency to smaller stain diameters and higher numbers of satellite spatter. While this contradicts expectations from elevated viscosity values, we associate this trend to microscopic inhomogeneities due to storage. We recommend CPDA-1 for prolonged storage of BPA samples and suggest the use of comprehensive test protocols including viscoelasticity for determination of the maximum shelf life of pig blood.

Colonization of newborn piglets with beneficial and ubiquitous microorganisms in combination with colostral passive immunity is the prerequisite for development of immunity and gut maturation. In this study living strains of Clostridium perfringens type A (CpA) and non-pathogenic Escherichia (E.) coli strains harvested from healthy piglets were administered to piglets prior to first colostrum intake in order to prevent disease caused by pathogenic variants of the same bacterial species by competitive exclusion. In addition, it was investigated whether these potential beneficial colonizers were able to prevent harmful effects of infection with Cystoisospora (C.) suis as a primary invasive pathogen. In a first trial, half of the piglets from four litters were treated with a bacterial cocktail consisting of two E. coli and four CpA strains immediately after birth on two consecutive days, while the other half of the litters served as control group. In a second trial, piglets were treated following the protocol of the first trial, and additionally all piglets were infected 4 h after the end of littering with ~1,000 sporulated oocysts of a C. suis laboratory strain. General health, body weight development, fecal consistency and, in the second trial, oocyst excretion were monitored from birth until weaning. No adverse effects of the cocktail on the health status were observed. Treated piglets of the first trial showed a higher average daily weight gain until weaning. In the second trial, no significant differences were found with respect to average daily weight gain, fecal consistency, amount, and duration of oocyst excretion assessed in daily samples. In treatment group 51.1% and in the control group 38.5% of the fecal samples were positive for oocysts in autofluorescence. The average duration of oocyst excretion was longer in treatment group (7.7 days) than in control group (5.6 days). Application of bacterial cocktail could not effectively minimize disease symptoms caused by C. suis. There was a trend toward an increase in severity of disease symptoms in treated pigs, suggesting that the synergism between CpA and C. suis was independent of the bacterial strains, but is exclusively dominated by the pathogenic effect of C. suis.

Background Listeria (L.) monocytogenes as the causative agent of listeriosis in humans and different animal species, has its reservoir in the environment. It can be found in the gut and faeces of healthy pigs, but under certain circumstances it may cause clinical disease. Fatteners are usually not known to get affected by Listeria-associated septicaemia and enteritis. This case report shows, that L. monocytogenes should be part of the list of differential diagnoses, when fattening pigs suffer from haemorrhagic diarrhoea and septicaemia. Case presentation Here, we report of an episode of fatal listeriosis in fattening pigs in a piglet producing farm in Lower Austria, which was combined with a fattening unit with space for 450 fatteners. The mortality rate resulted in 7.8% among fattening pigs after suffering from clinical symptoms such as anorexia, bloody diarrhoea and increased body temperature. Two fattening pigs with clinical symptoms and maize silage samples were used for further diagnostics. L. monocytogenes were isolated from serosa samples of the pigs and in the corresponding fed maize silage. One animal was positively tested for Brachyspira hyodysenteriae, which may have also been involved in the development of colitis. Immunohistochemically, L. monocytogenes could be detected in high amounts in lymphatic tissue of the gut. Molecular biological characterisation of the L. monocytogenes isolates from pigs and maize silage resulted in an identical DNA-fingerprint assigned to sequence type (ST) 21. Additionally, a high content of deoxynivalenol (3000 parts per billion) was found in maize silage. Therefore, the maize silage produced under inappropriate ensilaging conditions in a silo, was most likely the source of infection. Antimicrobial therapy with amoxicillin led to a fast cure of the remaining affected fatteners. Conclusion To conclude, we were able to show, that L. monocytogenes can cause clinical disease in finishing pigs, which may have been a result of immunosuppression due to high deoxynivalenol exposure. When feeding silage it is important that all ensilaging procedures occur under appropriate anaerobic conditions to guarantee suppression of listerial growth. Electronic supplementary material The online version of this article (10.1186/s12917-018-1687-6) contains supplementary material, which is available to authorized users.

We present artificially motorized sperm cells-a novel type of hybrid micromotor, where customized microhelices serve as motors for transporting sperm cells with motion deficiencies to help them carry out their natural function. Our results indicate that metal-coated polymer microhelices are suitable for this task due to potent, controllable, and nonharmful 3D motion behavior. We manage to capture, transport, and release single immotile live sperm cells in fluidic channels that allow mimicking physiological conditions. Important steps toward fertilization are addressed by employing proper means of sperm selection and oocyte culturing. Despite the fact that there still remain some challenges on the way to achieve successful fertilization with artificially motorized sperms, we believe that the potential of this novel approach toward assisted reproduction can be already put into perspective with the present work.

Highlights • Porcine astrovirus type 4 was prevalent in the 49 European farms with a high viral load. • Rotaviruses were mainly found in diarrheic pigs. • Kobuvirus and porcine circovirus 2 were ubiquitous., Enteric viral infections in pigs may cause diarrhea resulting in ill-thrift and substantial economic losses. This study reports the enteric infections with porcine astrovirus type 4 (PAstV4), porcine group A rotavirus (GARV), porcine group C rotavirus (GCRV), porcine circovirus type 2 (PCV2) and porcine kobuvirus (PKoV) in 419 pigs, comprising both healthy and diarrheic animals, from 49 farms in five European countries (Austria, Germany, Hungary, Spain and Sweden). Real-time RT-PCR assays were developed to test fecal samples and to compare the prevalence and viral load in relation to health status, farms of origin and age groups. The results showed that PAstV4 (70.4%) was the dominant virus species, followed by PKoV (56.7%), PCV2 (42.2%), GCRV (3%) and GARV (0.9%). Diarrheic pigs had a higher viral load of PAstV4 in the nursery and growing-finishing groups. Rotaviruses were mainly detected in diarrheic pigs, whereas PCV2 was more often detected in clinically healthy than in diarrheic pigs, suggesting that most PCV2 infections were subclinical. PAstV4, PCV2 and PKoV were considered ubiquitous in the European pig livestock and co-infections among them were frequent, independently of the disease status, in contrast to a low prevalence of classical rotavirus infections.

The apicomplexan parasite Cystoisospora suis which causes neonatal porcine coccidiosis is one of the predominant parasite in suckling piglets. Currently, the immunofluorescence antibody test (IFAT) is the only available serological tool for detecting serum antibodies against C. suis which has several limitations, including bias from interpretation and low throughput. In the present study, an indirect enzyme-linked immunosorbent assay (ELISA) was developed using a previously characterized recombinant merozoite protein for the detection of specific immunoglobulin G (IgG) and IgA against C. suis. The recombinant protein was expressed in Escherichia coli as a N-terminal histidine fusion protein, and its specificity was confirmed in an immunoblot probed with highly positive anti-C. suis sera from experimentally infected piglets. Optimal dilutions of recombinant protein, sera and conjugate were determined by checkerboard titrations, and the serum dilution that gave the greatest ratio between the positive and the negative sera was selected for subsequent analyses. Agreement between the IFAT and the newly developed ELISA was assessed with kappa statistics. The receiver operating characteristic (ROC) curve analysis based on 185 serum samples with known C. suis exposure previously tested in the reference IFAT was used to determine the cut-off value, sensitivity and specificity of the ELISA. For IgG, the ELISA had an estimated cut-off value of 0.82 and sensitivity and specificity values of 94.7% and 98%, respectively, whereas for IgA the estimated cut-off value was 0.41 and sensitivity and specificity values were both100%. According to kappa coefficient, an excellent correlation (κ > 0.8) was found between IFAT and ELISA for both isotypes. The diagnostic accuracy of the test measured as the area under the ROC curve index scaled between 0.98 and 1.0, indicating high discriminatory capacity and its possible application as a serological tool for detecting antibody response in the host following C. suis exposure/immunization and large-scale surveillance studies.

Gastric ulcerations in finishing pigs can cause growth restriction, sudden death and contamination of the carcass by invading microorganisms. The aim of the study was to compare macroscopic and histological findings of the stomach mucosa in fattening pigs kept at 1m²/pig and provided with long straw (10 groups, 113 pigs) with a control group kept at 0.7m²/pig without straw (11 groups, 120 pigs). At slaughter, the gastric health of pigs was assessed by macroscopic and histological scoring of 233 stomachs ranging from 0 (no alteration of mucosa) to 3 (ulceration). Gastric scores were correlated with organ alterations, carcass lesions and blood parameters. Based onto histological findings after gold standard sensitivity and specificity of macroscopic findings for ulceration (score 3) were 53 % and 98 %, respectively. While the extent of mucosal alterations can be assessed by macroscopic scoring easily at slaughter, histological examination reveals the depth of alterations. Median group prevalences of gastric ulcerations diagnosed by macroscopic examination were 5 % in the control group (range 0–40 %) and 18 % in the straw group (range 0–50 %), with no significant difference between both groups. Macroscopic scores were significantly higher in the straw group. Prevalence of ear-tip lesions was positively correlated with gastric health (p < 0.05). Analysis of particle size distribution in feed revealed, that more than 50 % of the feed consist of particles with less than 0.5 mm in diameter. The fine-ground diet in this herd was therefore identified as an important risk factor for the development of gastric ulceration on this farm. As a conclusion, the known risk factor of a high proportion of small particles in diet was not compensated by possible positive effects of straw and more space, and should be eliminated with high priority. Key words: ear tip lesions; histology; mucosa alterations; stomach; straw; swine  OCENJEVANJE GASTRIAŒNIH ULKUSOV PRI PRAA IAŒIH PITANCIH, NASTANJENIH Z NASTILJEM ALI BREZ NASTILJA IN DODATNEGA PROSTORA – MAKROSKOPSKA IN MIKROSKOPSKA A TUDIJA NA KONVENCIONALNIH AVSTRIJSKIH KMETIJAH GastriAne ulceracije pri praAiiAih pitancih v zakljuAni fazi lahko povzroAijo omejevanje rasti, nenadno smrt in kontaminacijo trupa z invazivnimi mikroorganizmi. Cilj raziskave je bil primerjava makroskopskih in histoloAikih ugotovitev v sluznici A¾elodca pri pitovnih praAiiAih, ki so nastanjeni na 1m²/praAiiAa in imajo nastilj sestavljen iz dolge slame (10 skupin, 113 praAiiAev) v primerjavi s kontrolno skupino, ki je bila nastanjena na 0,7 m²/praAiiAa in z nastiljem brez slame (11 skupin, 120 praAiiAev). Pri zakolu je bilo A¾elodAno zdravje praAiiAev ocenjeno z makroskopskim in histoloAikim toAkovanjem, opravljenem na 233 A¾elodcih, z ocenami, ki se gibljejo od 0 (brez spremembe sluznice) do 3 (ulceracija). Rezultate opazovanj sluznice A¾elodcev smo nato povezali s spremembami organa, poAikodbami trupa in krvnimi parametri. Medtem ko se obseg sprememb sluznice lahko oceni z makroskopskim merjenjem pri zakolu, histoloAiki pregled razkrije globino sprememb. Mediana prevalenca A¾elodAnih ulkusov, diagnosticiranih z makroskopskim pregledom, je bila 5 % v kontrolni skupini (razpon od 0 do 40 %) in 18 % v skupini z nastiljem iz slame (razpon od 0 do 50 %), pri Aemer ni bilo opaziti znaAilne razlike med skupinama. Makroskopski rezultati so bili precej viAiji v skupini z nastiljem iz slame. RazAiirjenost poAikodb uAies je bila pozitivno povezana z zdravjem A¾elodca (p

Cystoisospora suis is the most pathogenic species of coccidia in suckling piglets, affecting them predominantly within their first three weeks of life. The clinical signs of neonatal cystoisosporosis include watery diarrhea and wasting, leading to significant economic losses for the farmer. Since neonatal piglets have an immature immune system, colostral transfer of maternal factors such as immune cells or antibodies is essential for controlling infections at that age. However, the role of C. suis -specific antibodies transferred from the sow to the piglets and possible correlations between antibody levels in the piglets acquired from colostrum with the clinical outcome of disease are currently not understood. To address this issue, 12 non-infected piglets and 14 piglets experimentally infected with C. suis on the third day of life were examined during their first four weeks of life. IgG, IgA, and IgM titers in the blood serum specific for sporozoites and merozoites of C. suis were evaluated, along with oocyst excretion and fecal consistency. Additionally, the antibody content in the colostrum and milk of three mother sows was determined. A transfer of naturally acquired C. suis -specific antibodies from sows to piglets with the colostrum could be demonstrated. Maternal antibodies in piglets’ blood sera did not persist for longer than 14–21 days except for IgG which was present in high titers until the end of the study. Within 2–3 weeks after birth the onset of endogenous antibody production was noticed. Titers in blood serum showed a correlation with the severity of diarrhea which was positive for IgG and IgM (possibly due to increased consumption or loss of these antibodies) and negative for IgA. C. suis -specific mucus antibodies isolated from infected and non-infected piglets ( n = 6/group) on the 28th day of life were present in both groups, showing significantly higher titers of IgA and IgM in infected piglets. Maternally transferred antibodies acquired by natural infections of sows as observed in this study did not provide protection against the clinical manifestation of disease. The level and effect of transferrable maternal factors necessary for protection still need to be elucidated. However, correlations between antibody titers and fecal consistency in the piglets indicate that C. suis -specific antibodies might be useful markers for the expectable clinical severity of cystoisosporosis.

Cystoisospora (syn. Isospora) suis is a leading cause of diarrheal disease in neonatal piglets. To address the possibility of maternal immunization against C. suis infection six non-naive pregnant sows were superinfected with 100,000 oocysts 2 weeks ante partum and compared to non-superinfected animals. Their piglets were infected with 1000 oocysts on the third day of life. Clinical and parasitological parameters as well as antibody titers in colostrum/milk and blood of sows and in the blood of piglets were evaluated by IFAT against sporozoites and merozoites from 2 weeks ante partum until the 35th day after birth. For IFAT two different invasive stages of C. suis were used to find possible differences between the immune response against the initially infectious stages (sporozoites) and later occurring asexual developmental stages (merozoites), which might be responsible for persisting/extraintestinal infections. IFN-γ production of PBMC and piglet splenocytes was determined by ELISPOT. Maternal superinfection resulted in increased titers of IgA, IgM and IgG in colostrum and milk as well as in the blood of sows and their piglets. Oocyst shedding and diarrhea were observed in the offspring of both groups, but piglets of superinfected sows showed significantly reduced oocyst shedding and less diarrhea. This protective effect was correlated with increased titers of antibodies, especially IgA, in colostrum, milk and blood serum of sows and piglets, and with the reactivity of splenocytes to parasite antigen. Superinfection of sows ante partum could partially protect piglets against the clinical outcome of experimental infection. Both colostrum and milk contain maternal protective substances as the effect of protection was highly correlated with antibody titers during the first 2 weeks of life. IgA in different substrates may serve as a marker for the level of protection against clinical cystoisosporosis.

For reliable predictions of clinical and parasitological outcome of experimental infections with parasites, different models must be evaluated for possible influences of infection time point, infection dose and host-specific parameters such as breed or litter size. To address these issues for Cystoisospora (syn. Isospora) suis, the causative agent of porcine neonatal coccidiosis, 181 piglets from 90 litters (hybrid crosses of different breeds) were included in a retrospective study to evaluate differences in time point and dose of infection in four different experimental models ((1) 1,500 oocysts on the 4th day of life, d.o.l.; (2) 1,000 oocysts, 4th d.o.l.; (3) 1,000 oocysts, 1st d.o.l.; (4) 5,000 oocysts, 4th d.o.l.). The target variables body weight gain, faecal consistency and oocyst excretion were evaluated during the acute phase of infection (5-10 days post infection), and the influences of the dependent variables breed or litter size were estimated. Despite differences in the time course of excretion and faecal consistency, neither the average amount of excretion nor the average faecal consistency differed among models, breeds or litters of different size. High individual variability was seen in all four models as described earlier for higher infection doses. When infections on the 1st vs. 4th day of life were compared, no differences in averages could be found, in contrast to previous observations on the influence of age. Other, not yet defined, variables appear to have a greater impact on the outcome of infection than doses and time points in the tested range, despite the reliable outcome of infection with high excretion rates and signs of clinical disease.