Pseudorabies virus antibodies in swine slaughtered in Iowa.

Sera from butcher swine (1,246 total) were evaluated qualitatively by the microimmunodiffusion test and quantitatively by the virus neutralization test for antibody to pseudorabies virus. Ten percent of the sera had antibody to pseudorabies virus. Follow-up contact with veterinarians whose clients included the farms from which the positive swine originated revealed that few feeder swine are vaccinated against pseudorabies and that most infections with pseudorabies virus are subclinical.     

Prevalence of toxoplasmosis in swine from Iowa

Of swine from 104 herds, 2,616 were tested for antibodies against Toxoplasma gondii, using an ELISA. Data were analyzed according to swine type, herd size, facility type, and season. The true prevalence of toxoplasmosis was estimated as 5.4% among finishing swine and 11.4% among sows and gilts. Herds with less than 100 breeding swine were significantly (P less than 0.05) more likely to be infected than were herds with greater than or equal to 100 breeding swine. The rate of seropositivity in breeding swine was approximately the same in infected herds, regardless of herd size. Herds with finishing swine maintained in total confinement were as likely to become infected as were herds maintained in other types of facilities, but infected herds with finishing swine maintained in confinement appeared to have a lower in-herd prevalence than did herds maintained in other types of facilities (P = 0.09). Seasonal effects were not observed, and prevalence remained relatively constant throughout the year.     

Seroprevalence of antibodies against encephalomyocarditis virus in swine of Iowa.

A total of 2,614 swine from 104 herds located throughout Iowa were tested for antibodies against encephalomyocarditis virus (EMCV) by use of the microtitration serum neutralization test. The sample was composed of 587 sows and gilts and 2,027 finishing swine. A statistically significant (P less than 0.002) difference was observed between prevalence in sows and gilts (17.2%) and that in finishing swine (12.2%). Breeding swine maintained in total confinement (20.5%) had significantly (P = 0.04) higher prevalence than did breeders maintained in other types of housing (12.1%), whereas prevalence in finishing swine raised in total confinement (6.4%) was significantly (P = 0.02) lower that in finishers not raised in total confinement (13.6%). Association was not detected between prevalence and herd size or between prevalence and season of the year. Adjusting for test specificity and sensitivity, the true prevalence of EMCV infection in swine in Iowa was estimated to be 13.8% in breeding stock and 8.5% in finishing swine. On a herd basis, 89.4% (93/104) of the herds had one or more EMCV-positive swine.     

Prevalence of exposure to Salmonella spp in finishing swine marketed in Iowa

OBJECTIVE: To describe the prevalence of antibodies against Salmonella spp in swine marketed in Iowa. ANIMALS: Swine marketed by 1,044 low-volume producers and 45 high-volume producers. PROCEDURE: Samples of diaphragm muscle collected from swine carcasses were tested by an indirect ELISA based on lipopolysaccharides from Salmonella spp, in particular Salmonella serovar Typhimurium. Prevalence of positive results for antibodies against Salmonella spp for carcasses, lots, and swine for each producer was determined. Producer-level seroprevalence was used to classify swine from producers as having negligible, low, moderate, or widespread evidence of previous or historical exposure to Salmonella spp. RESULTS: From low-volume producers, 23,609 of 25,478 (92.7%; 95% confidence interval [CI], 92.4% to 92.9%) samples had negative results, and 1,863 (7.3%; 95% CI, 7.05% to 7.56%) had antibodies against Salmonella spp. Of the 6,299 lots of swine tested, 1,191 (18.9%) contained at least 1 sample with positive results. From high-volume producers, 203 of 2,486 (8.1%; 95% CI, 6.8% to 9.3%) samples had antibodies against Salmonella spp, and 124 of 629 lots had at least 1 sample with positive results for antibodies against Salmonella spp. CONCLUSIONS AND CLINICAL RELEVANCE: Less than 10% of pigs marketed in Iowa are apparently exposed to Salmonella spp. Most swine marketed by low-volume producers had negligible or little evidence of exposure to Salmonella spp, whereas a higher percentage of swine marketed by high-volume producers had positive results when tested to detect antibodies against Salmonella spp.     

Ochratoxicosis in Iowa swine

Ochratoxicosis was diagnosed in 2 Iowa swine herds. In both cases, clinical signs consisted of increased urination and water consumption. Pale tan kidneys were found in affected pigs at necropsy. Histologic examination of renal tissue from an affected pig revealed diffuse tubular nephrosis and interstitial fibrosis. In both cases, ochratoxin A was detected by thin-layer chromatography in extracts of whole corn and ground complete feed. Ochratoxicosis was reproduced in swine with feed obtained in one of the cases.     

Prevalence of antibodies against feline coronavirus and Chlamydophila felis in Swedish cats

Serum samples from 214 Swedish cats with no signs of infectious disease were analysed for the presence of antibodies against Chlamydophila felis (Cp felis), while 209 of these were also analysed for feline coronavirus (FCoV) antibodies. The prevalence of antibodies against Cp felis was 11%, with no significant difference between purebred and mixed breed cats. The overall prevalence of antibodies against FCoV was 31%, significantly higher among pure breed cats (65%) than among mixed breed cats (17%). A high proportion of cats with antibodies against FCoV had relatively high antibody titres, and was therefore likely to be shedding FCoV in faeces. For Cp felis, the majority of seropositive animals had relatively low antibody titres, and the risk of these animals infecting others is not known.     

A serosurvey of swine and free-living species on Iowa farms for antibodies against encephalomyocarditis virus

Swine and free-living nonporcine species from 20 Iowa swine farms were surveyed for antibodies against encephalomyocarditis virus (EMCV). The microtitration serum neutralization test was used, and antibody titers ≥ 1:8 were considered positive. The overall prevalence in 267 sows in various groups was 37.8% (range 20-86%). The prevalence in sows maintained in total confinement was significantly lower than in sows not maintained in total confinement (p = 0.01). Prevalence in sows was not associated with other herd characteristics or with abundance estimates of rats and/or mice.

Free-living animals tested included 74 domestic cats (Felis domestica), 203 house mice (Mus musculus), 15 mice of the genus Peromyscus, nine Norway rats (Rattus norvegicus), 34 opossums (Didelphis virginiana), 14 raccoons (Procyon lotor), and seven striped skunks (Mephitis mephitis). Of these, the only seropositive animals were two domestic cats.

The results of this study failed to implicate the free-living species surveyed as important reservoirs of EMCV for swine, and suggested that swine themselves and/or some species not included in this survey are the main reservoir of EMCV for swine in Iowa.

     

Enzyme-linked immunosorbent assay for the detection of porcine epidemic diarrhea coronavirus antibodies in swine sera

An enzyme-linked immunosorbent assay (ELISA) for detecting serum antibodies to the porcine epidemic diarrhea coronavirus (PEDV) was established by using cell culture-grown PEDV as antigen for coating. Ultracentrifugation through 20 and 45% (w/w) sucrose cushions proved to be the best antigen purification method. Examination of 1024 swine sera showed a high specificity and a greater sensitivity of the ELISA, when compared with indirect immunofluorescence. Reference sera with high antibody titers to PEDV originated from two pigs experimentally infected with PEDV. Three different antigen purification methods and the advantages of the ELISA compared with an immunofluorescence test are discussed.     

Prevalence of Toxoplasma gondii antibodies in southern Louisiana swine in 1980 and 1981

Sera from 1,219 pigs slaughtered in southern Louisiana in 1980 and 1981 were tested, using the indirect hemagglutination test and microtitration system, for Toxoplasma gondii antibodies; 19.19% had titers of greater than or equal to 1:64. Pigs slaughtered in the colder months, November to March, had significantly higher seroprevalences than did pigs slaughtered in the warmer months. Examination of blood samples from 236 sows and gilts on 52 farms revealed a seroprevalence of 24.6%.     

Prevalence of antibodies to porcine adenovirus in swine by indirect fluorescent antibody test

An indirect fluorescent antibody test was developed for routine identification of a porcine adenovirus and its specific antibody. Two specific-pathogen-free young pigs were inoculated with the viral antigen prepared in continuous porcine kidney cell cultures, and their sera were used as an antibody reagent to standardize the test. Sera of adult pigs with respiratory problems, obtained from pig farms in Quebec, were tested for antibodies to this virus; 83 of 540 sera tested (15.2%) were found to be positive.     

Toxoplasma gondii antibodies in California swine.

In a serologic survey for Toxoplasma gondii in 891 swine from 20 California counties, 478 (54%) were seronegative, 153 (17%) were nonspecific reactors, and 260 (29%) were seropositive. Most of the titers (81%) were low, ie, from 1:64 to 1:128, but a few (2%) were high, ie, 1:1024 or greater.     

Prevalence of African swine fever virus and classical swine fever virus antibodies in pigs in Benue State,Nigeria

Tropical Animal Health and Production - This study investigated the prevalence of African swine fever virus (ASFV) and classical swine fever virus (CSFV) antibodies in pigs in Benue State, Nigeria....     

Serum antibodies to bovine coronavirus in Swedish sheep.

Altogether 218 sheep sera from 40 flocks in different parts of Sweden were screened for antibodies to bovine coronavirus (BCV). Nineteen per cent of the sera were positive and there was a significantly higher frequency (p < 0.05) of at least one positive sample in flocks with more than 100 adult sheep than in smaller flocks. There was also a significantly higher frequency (p < 0.001) of positive samples from sheep older than 4 years than from younger ones. Only a weak relationship between BCV positivity (2 or more positive samples, p < 0.05) and cattle contact was demonstrated in this study. Possible transmission routes and other factors that could have affected the result are discussed. In light of our finding that all 5 sheep experimentally exposed to BCV through contact with infectious cow faeces seroconverted, we conclude that the antibodies found in Swedish sheep are probably the result of BCV infections directly or indirectly transmitted from cattle.