应用琼脂免疫扩散试验检测猪伪狂犬病抗体的研究

建立了ＡＧＩＤ用于猪伪狂犬病（Ｐｓｅｕｄｏｒａｂｉｅｓ,Ｐｒ）的诊断。对９８份被俭血清的ＡＧＩＤ结果与ＳＮ结果比较,当ＳＮ滴度大于１：８时两者的阳性检出符合率为１００％,ＳＮ滴度小于或等于１：８时,两者的阳性检出符合率为８７．５％,ＡＧＩＤ和ＳＮ总的阳性符合率为９４．４％,结果表明,ＡＧＩＤ对Ｐｒ可进行特异性诊断,流行病学调查和免疫动态监测。     

Outbreaks in Quebec pig farms of respiratory and reproductive problems associated with encephalomyocarditis virus.

Encephalomyocarditis virus (EMCV) was isolated from tissues of aborted fetuses and weaned and suckling piglets from 4 different pig farms in Quebec. The farms were experiencing reproductive failure in sows of different parities concomitant to respiratory problems in suckling and postweaning piglets. At necropsy, gross lesions were confined to the lung and consisted of pulmonary congestion and edema of various degrees. Lesions of multifocal interstitial to proliferative pneumonia were found in the lungs of these piglets. Bacteriologic examination of various tissues from necropsied pigs yielded no pathogens in most cases. No significant antibody titers against 3 swine viruses (transmissible gastroenteritis virus, porcine parvovirus, and swine influenza virus) and two bovine viruses (bovine viral diarrhea and infectious bovine rhinotracheitis viruses) were detected in the sera of convalescent pigs. The Quebec EMCV isolates were antigenically related to the reference ATCC-VR129 strain of EMCV, as demonstrated by indirect immunofluorescence, serum neutralization (SN), and Western immunoblotting. However, one of the Quebec isolates could be distinguish by SN. EMCV-specific SN antibody titers up to 1:12,800 were detected in thoracic and ascitis fluids of aborted fetuses and in sera of convalescent pigs. A possible pneumotropic EMCV variant in swine may exist.     

Improvements to the hemagglutination inhibition test for serological assessment of recombinant fowlpox-H5-avian-influenza vaccination in chickens and its use along with an agar gel immunodiffusion test for differentiating infected from noninfected vaccinated animals

In general, avian influenza (AI) vaccines protect chickens from morbidity and mortality and reduce, but do not completely prevent, replication of wild AI viruses in the respiratory and intestinal tracts of vaccinated chickens. Therefore, surveillance programs based on serological testing must be developed to differentiate vaccinated flocks infected with wild strains of AI virus from noninfected vaccinated flocks in order to evaluate the success of vaccination in a control program and allow continuation of national and international commerce of poultry and poultry products. In this study, chickens were immunized with a commercial recombinant fowlpox virus vaccine containing an H5 hemagglutinin gene from A/turkey/Ireland/83 (H5N8) avian influenza (AI) virus (rFP-H5) and evaluated for correlation of immunological response by hemagglutination inhibition (HI) or agar gel immunodiffusion (AGID) tests and determination of protection following challenge with a high pathogenicity AI (HPAI) virus. In two different trials, chickens immunized with the rFP-H5 vaccine did not develop AGID antibodies because the vaccine lacks AI nucleoprotein and matrix genes, but 0%-100% had HI antibodies, depending on the AI virus strain used in the HI test, the HI antigen inactivation procedure, and whether the birds had been preimmunized against fowlpox virus. The most consistent and highest HI titers were observed when using A/turkey/Ireland/83 (H5N8) HPAI virus strain as the beta-propiolactone (BPL)-inactivated HI test antigen, which matched the hemagglutinin gene insert in the rFP-H5 vaccine. In addition, higher HI titers were observed if ether or a combination of ether and BPL-inactivated virus was used in place of the BPL-inactivated virus. The rFP-H5 vaccinated chickens survived HPAI challenge and antibodies were detected by both AGID and HI tests. In conclusion, we demonstrated that the rFP-H5 vaccine allowed easy serological differentiation of infected from noninfected birds in vaccinated populations of chickens when using standard AGID and HI tests.     

三种检测禽流感抗体方法的比较

应用胶体金免疫层析法(GICA)、血凝抑制试验(HI)和琼脂扩散试验(AGID)三种方法同时检测所采集的342份鸡血清样品,并对三者的检测结果进行比较。结果发现,HI试验的阳性检出率最高(78.65%),其次为GICA(69.88%)和AGID试验(59.36%);GICA与HI的符合率为89.47%,与AGID的符合率为84.21%,HI与AGID的符合率为80.70%。结果表明,GICA比AGID试验更为敏感,且与HI试验有较好的符合率,可用于禽流感的血清学监测。     

An enzyme-linked immunosorbent assay for detection of antibodies to maedi-visna virus in sheep. II. Comparison to conventional agar gel immunodiffusion test.

A study was conducted to compare the indirect enzyme-linked immunosorbent-assay (i-ELISA) test using antigen prepared by a simple technique using sodium dodecyl sulfate (SDS) treatment to the conventional agar gel immunodiffusion test (AGID). Ten specific-pathogen-free (SPF) sheep were inoculated with maedi-visna virus (MVV) and serum antibody titers compared over a period of 14 weeks. All the sheep seroconverted by the i-ELISA compared to 90% by the AGID. The i-ELISA detected antibody at a mean of 2.6 weeks prior to the AGID. In both tests, fluctuations were observed in the serum antibody response of two sheep. The i-ELISA had a specificity of at least 98.8% and an increased relative sensitivity of 15.5% compared to the AGID, based on the analysis of sera from experimental sheep with MVV free status and sera from sheep from various sources. Of the sera from a seronegative flock which had been monitored with the AGID after a "test and remove" eradication program, 10.2% were positive by the i-ELISA. It was concluded that the AGID test may not be adequate to monitor samples for an eradication scheme.     

A competitive ELISA for detection of antibodies to the group antigen of bluetongue virus.

A competitive enzyme-linked immunosorbent assay (cELISA) was developed to detect antibodies to the group antigen of bluetongue virus (BTV). The epitope recognized by the BTV-specific monoclonal antibody was confirmed, by immunofluorescence staining of monolayers of virus-infected Vero cells, to be present on BTV serotypes 2, 10, 11, 13, and 17 but not on epizootic hemorrhagic disease virus (EHDV) serotypes 1 and 2. Sera from BTV-inoculated ruminants and rabbits were used to evaluate the cELISA and to compare its specificity and sensitivity with that of the conventional BTV-specific agar gel immunodiffusion (AGID) and serum neutralization (SN) tests. Rabbit antisera to the 5 serotypes of BTV present in the United States had cELISA titers (inverse of the final dilution of serum that gave greater than 20% inhibition) that ranged from 32 to greater than 1.024. Seroconversion of the 8 calves and lambs inoculated with BTV was detected by all 3 serologic tests (SN, AGID, cELISA) by 6 weeks after inoculation. Specificity of the cELISA test was confirmed with bovine sera that contained neutralizing antibodies to EHDV but not to the 5 serotypes of BTV present in the United States; these sera gave positive results by AGID test but were negative by cELISA. The sensitivity and specificity of the cELISA test was further confirmed by analysis of a panel of bovine test sera supplied by the National Veterinary Services Laboratories, indicating that the cELISA is a superior test for detection of BTV group-specific antibodies in sera from ruminants in the United States.     

Detection of antibodies to avian pneumovirus by a micro-indirect immunofluorescent antibody test.

A micro-indirect immunofluorescent antibody (micro-IFA) test with a 96-well, flat-bottomed microplate was developed for measuring avian pneumovirus (APV) antibodies. Two Japanese APV strains (MM-1, 8597/CV94) isolated at different places and times and Vero cells were used for antigen preparation in this test. The test results were compared with those of a serum neutralization (SN) test. By the micro-IFA test, specific immunofluorescent antigens were observed in the cytoplasm of cells infected with either strain, and the antibody titers of antisera to these strains were quite similar. In most cases, the results were obtained within 3 hr. Antibody titers between the micro-IFA and SN tests were highly correlated, with correlation coefficients of 0.873 (MM-1 strain) and 0.889 (8597/CV94 strain). We also investigated APV antibody status in two farms for a period of about 2 yr by the micro-IFA test and revealed that APV infections were repeated within these farms. On the basis of these results, we conclude that our micro-IFA test is useful for routine serologic surveys of APV infections, particularly when a large number of samples are to be treated, because this test was time and labor saving relative to SN tests or conventional IFA tests utilizing embryo tracheal organs or coverslip cell cultures.     

A field study of persistence of antibodies in California horses vaccinated against western, eastern, and Venezuelan equine encephalomyelitis.

As a result of the continuing threat of Venezuelan equine encephalomyelitis (VEE), a study was made to determine if revaccination against VEE (TC-83 vaccine) was feasible and if revaccination could be incorporated into other routine vaccination practices. Of the horses given annual vaccination with bivalent western equine encephalomyelitis (WEE) and eastern equine encephalomyelitis (EEE) vaccine, 57% retained detectable serum-neutralizing (SN) antiboyd titers for VEE 18 months after the initial VEE vaccination was given. Of horses with no record of WEE-EEE vacinnation, 100% retained detectable VEE SN antibody titers over the same period. The VEE geometric mean titer was 25 times greater for horses not previously vaccinated against WEE-EEE than for horses given annual WEE-EEE vaccination at the time of VEE vaccination. In horses vaccinated against VEE 18 months previously, the geometric mean titer increased from 4 to 70 at 48 days after the intitial WEE-EEE vaccination. This increase indicated that similar antigenic factors for VEE are possibly present in bivalent WEE-EEE vaccine. In horses previously vaccinated against WEE-EEE and VEE, the best SN antibody response to VEE revaccination occurred when VEE vaccine was given simultaneously with the bivalent WEE-EEE vaccine. Of 150 serum samples tested by both the SN and the hemagglutination-inhibiton tests, agreement between positive reactions at greater than or equal to 1:10 was 70% for VEE, 81% for EEE, and 87% for WEE.     

Development and evaluation of indirect ELISA for the detection of antibodies against Japanese encephalitis virus in swine

The Japanese encephalitis virus (JEV) is one of causative agents of reproductive failure in pregnant sows. An indirect enzyme-linked immunosorbent assay (I-ELISA) was examined for its potential use in the rapid monitoring of the JEV, and the results were compared with those from the hemagglutination inhibition (HI) and serum neutralization (SN) tests. The comparative analysis showed that the results of I-ELISA showed a significant correlation with the conventional HI (r = 0.867) and SN tests (r = 0.804), respectively. When the I-ELISA results were compared with the traditional diagnostic assays, the sensitivity of the I-ELISA was 94.3% with the HI test and 93.7% with the SN test, respectively. The specificity was found to be 81.4% and 80.0% with the HI and SN tests, respectively. To determine the applicability of I-ELISA in the field, the serum samples from 720 pigs were collected from 4 regions in Korea between July and August 2004. The results indicated that 21.7% of screened pigs were seropositive for the JEV. The seropositive rates of JEV in the 4 provinces were 12.6% in Gyeonggi, 45.0% in Gyeongnam, 16.7% in Jeonbuk, and 12.2% in Jeju. The I-ELISA methodology developed in this study was shown to have considerable sensitivity and specificity through a comparison with HI and the SN tests. Therefore, it might be one of convenient methods for screening a large number of samples in various fields.     

Development and evaluation of an enzyme-linked immunosorbent assay for detection of bovine antibodies to epizootic hemorrhagic disease of deer viruses.

An indirect enzyme-linked immunosorbent assay (I.ELISA) is described for detection of bovine serum antibody to epizootic hemorrhagic diseases of deer virus (EHDV). Serum samples, at a dilution of 1:200, were incubated with group-specific EHDV antigens, pre-adsorbed to microtiter plates. Bound antibodies were detected by a murine monoclonal antibody to bovine immunoglobulin (Ig)G1 (heavy-chain specific) conjugated with horseradish peroxidase. The performance of the I.ELISA in detecting antibodies to EHDV in sequential serum samples from calves experimentally infected with serotypes 1,2,3 and 4 was evaluated. The I.ELISA detected EHDV antibodies from 14 days postinfection when seroconversion by the standard agar gel immunodiffusion (AGID) test was also evident. The group-specific antibodies to EHDV increased exponentially during the first two to four weeks postinfection and remained relatively stable for about 12 months in some calves. Unlike observations with the AGID test, no reaction was seen in the I.ELISA between blue-tongue virus (BTV) antigen and sera from calves given a single dose of EHDV. The performance of the I.ELISA and AGID were compared using 3,135 AGID negative bovine field sera from herds in Ontario, Alberta and British Columbia and 130 AGID positive samples collected from cattle in 1987 and 1988 during and after outbreaks of EHD in the Okanagan Valley, British Columbia. The specificity and sensitivity of the assay relative to the AGID test were 99.3% and 91.5% respectively, with an overall agreement of 99.0% between the tests.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of three enzyme-linked immunosorbant assays with the indirect immunofluorescent antibody test for the diagnosis of canine infection with Ehrlichia canis

The aim of this study was to compare three different enzyme-linked immunosorbant assays (recombinant major antigenic protein 2 (rMAP2)-ELISA, the Immunocomb (Biogal, Israel) and the Snap 3Dx assay (IDEXX Laboratories Inc., USA)) with the indirect immunofluorescent antibody test in detecting anti-Ehrlichia canis immunoglobulin-G (IgG) antibodies. Samples tested were collected from dogs suspected to be naturally infected with E. canis and from experimentally infected dogs.When qualitative results (positive/negative) were compared, there was an overall agreement of 81% (54/67) between the indirect immunofluorescence antibody (IFA) test and the rMAP2-ELISA. An overall agreement of 94% (63/67) was found between the IFA test and the Immunocomb, and an overall agreement of 91% (61/67) was found between the IFA test and the Snap 3Dx assay. In 50 of 67 (74.6%) samples tested, complete agreement in the qualitative results was found in all four tests. Sixteen of 17 samples with disagreement in the qualitative results were found to have IFA titers of 1:320 or less. The sensitivities and specificities of the tests were found to be 0.71 and 0.85 for the rMAP2-ELISA, 0.86 and 0.98 for the Immunocomb, and 0.71 and 1.00 for the Snap 3Dx assay.The tests performed in this study were found to be highly specific in detecting E. canis antibodies. Their sensitivity was found to be low with sera having IFA titers of < or =1:320, while high with sera having titers greater than 1:320. Repeating the serological tests 1-2 weeks after the first antibody assay may overcome the sensitivity problem with titers of < or =1:320.     

Comparison of a maedi-visna virus CA-TM fusion protein ELISA with other assays for detecting sheep infected with North American ovine lentivirus strains.

A maedi-visna virus CA-TM fusion protein ELISA (MVV ELISA) was evaluated for the detection of antibody in sheep infected with North American ovine lentivirus (OvLV). The results of the MVV ELISA were compared with other assays for OvLV antibody and with viral infection in an intensively studied group of 38 sheep with a high prevalence of OvLV infection and disease. The sensitivity, specificity, and concordance of assays for OvLV antibody (MVV ELISA, indirect ELISA, Western blot, and AGID), virus (virus isolation, PCR, antigen ELISA), and OvLV-induced disease in each animal were compared with OvLV infection status as defined by a positive result in two or more of the assays. Five sheep met the criteria for absence of OvLV infection. The sensitivity of the MVV ELISA in detecting OvLV infected sheep was 64%, whereas the sensitivity of the other three tests for antibody ranged from 85 to 94%. All the antibody assays were 100% specific in this group of animals. Of the assays for virus, the PCR test had the highest sensitivity and the best concordance with OvLV infection, but it also had the lowest specificity of any of the virus or antibody assays. Among the antibody tests, the concordance of the MVV ELISA compared most favorably with the AGID test for detecting OvLV-infected sheep. Analysis of serum samples from 28 lambs experimentally-infected with one of three North American strains of OvLV suggested that there were no significant strain differences detectable by antibody assay. Twenty virus-inoculated lambs were positive by both the MVV ELISA and the AGID test, five lambs were MVV ELISA negative and AGID test positive, and three lambs were MVV ELISA positive and AGID test negative. No pre-inoculation samples were positive by either assay. In a longitudinal study involving seven lambs, antibodies to OvLV were detected by AGID 3-5 weeks post-inoculation, but were not detected by MVV ELISA until 5-10 weeks post-inoculation. Among 128 naturally and experimentally-infected sheep that were seropositive in the AGID test, the overall sensitivity of the MVV ELISA was higher in the naturally infected sheep (84%) than in the experimentally infected sheep (69%). The data indicated that the MVV ELISA represents a less sensitive, but specific alternative for the detection of OvLV antibodies.     

A short incubation serum neutralization test for bovine viral diarrhea virus.

A three day serum neutralization (SN) test for the detection of antibodies to bovine viral diarrhea virus (BVDV), which is an improvement on the existing five day test, is described. The improved test results in a more rapid viral cytopathic effect and utilizes Madin Darby kidney (MDBK) cells, and horse serum as a medium supplement. A comparison of tests utilizing the NADL and the Singer strains of BVDV and the use of either secondary bovine kidney cells with calf serum (BKCS) or continuous MDBK cells with horse serum (MDHS) was performed. Analysis of the SN results of 685 serum samples from 445 Quebec and Ontario cattle showed that there was no difference, as expected, in the means of the SN antibody titers when the NADL strain was used in either the BKCS or MDHS system but SN antibody titers were elevated (p less than 0.01) when the Singer strain was used in the MDHS system. The SN test with the Singer strain also yielded significantly higher titers for sera from 200 Alberta cattle.     

Comparison of four serologic tests for the detection of antibodies to bovine leukemia virus

Four tests for detection of antibodies to bovine leukemia virus (BLV) were compared. The sera that were tested came from cattle in naturally infected commercial dairy herds, cattle that were infected under experimental conditions, and cattle in an isolated BLV-free herd. The tests that were compared included a radioimmunoprecipitation assay (RIA) with p24 antigen, a RIA with glycoprotein (gp) antigen, an agar-gel immunodiffusion (AGID) test with gp antigen, and a virus-neutralization (VN) test that was based on inhibition of BLV-induced syncytia in cell culture. Results of the 4 serologic tests agreed for 96.8% of the sera from cattle in commercial herds. The gp RIA detected the greatest number of positive sera (188); it was followed in turn by the p24 RIA (187), the VN test (183), and the AGID test (176). The gpd RIA titers of the 12 sera that gave negative AGID results were 175 or less. In RIA, the percentage of precipitation of labeled antigen by positive sera was almost always higher with gp antigen than with p24 antigen. Satisfactory sensitivity in the p24 RIA required the acceptance of a low level of antigen precipitation, 15%, as a positive test. In the gp RIA, however, almost all positive sera precipitated at least 50% of the labeled antigen. Nonspecific precipitation of antigen in the RIA by sera from BLV-free cattle ranged from 4% to 10%. Examination of sequential serum samples from 17 experimentally infected cattle showed that BLV antibody was first detected 2 to 8 weeks after inoculation. In 9 cattle, seroconversion was detected simultaneously by all of the tests. Results from the other 8 cattle indicated that seroconversion could be detected first by p24 RIA, followed by the gp RIA and the VN test. The longest interval between RIA seroconversion and AGID seroconversion was 10 days. Monthly tests of sera from 10 laboratory cattle that were infected by contact exposure showed that 7 animals seroconverted in all tests at the same time. Two cattle were positive first in RIA, but the next month they were also positive in the VN and AGID tests. One animal was positive in the RIA and the VN test for 2 months before antibody was detected by AGID.     

Canine antibody response to Blastomyces dermatitidis WI-1 antigen

OBJECTIVE: To assess whether dogs with blastomycosis produce antibodies against the WI-1 and A-antigens of Blastomyces dermatitidis and whether the antibodies are useful in serodiagnosis. SAMPLE POPULATION: 359 serum samples obtained from 245 dogs. PROCEDURE: 233 samples from 122 dogs with blastomycosis, and 1 sample each from 24 dogs with suspected blastomycosis, 51 control dogs without infection, and 48 healthy dogs from an enzootic region were obtained. Antibodies against WI-1 antigen were detected by radioimmunoassay (RIA). Serum samples were tested in parallel for antibodies against the A-antigen of B dermatitidis by commercial agar-gel immunodiffusion (AGID) in a reference laboratory. RESULTS: Antibodies were detected in 92% of infected dogs by RIA and in 41 % by AGID. For 29 serum samples that were obtained 11 to 1,545 days after diagnosis, antibodies were detected in 92% of samples by RIA and 7% by AGID. For 93 serial serum samples from 29 dogs with blastomycosis, the mean anti-WI-1 titer was 1:18,761 at the time of diagnosis, and decreased to a mean of 1:1,338 by 210 days after treatment was initiated. Of 24 dogs with suspected infection, antibodies were detected in 67% by RIA and 33% by AGID. Control dogs without blastomycosis had no detectable antibodies in either assay. Thus, sensitivity was 92% for RIA and 41 % for AGID, and specificity was 100% for both tests. CONCLUSIONS AND CLINICAL RELEVANCE: Anti-WI-1 antibodies are readily detected by RIA in dogs with blastomycosis. Titers become high, decline during treatment, and persist for months. Anti-A antibodies are sometimes detected with AGID, but these decrease quickly.     

Immune response of the llama (Lama glama) to tetanus toxoid vaccination

An ELISA was developed to measure serum concentrations of tetanus toxoid-specific immunoglobulins. The titers obtained with this assay were compatible with those obtained by the standard mouse toxin-neutralization test. Serum samples from 123 llamas were analyzed for ELISA titers to tetanus toxoid. Of the 82 vaccinated adults, 75 (91%) had titers greater than or equal to 1:50. The vaccination status and titers of weanlings and juveniles (3 to 12 months old) varied; of the 21 vaccinated, 17 (81%) had titers greater than or equal to 1:50 and 7 of 9 (78%) unvaccinated llamas had titers less than 1:50. The ELISA titers of unvaccinated llamas less than 8 weeks old (crias) were matched with the maternal titers. All crias with titers less than 1:50 had dams with titers greater than or equal to 1:50.     

Evaluation of bluetongue virus diagnostic tests in free-ranging bighorn sheep

Five bluetongue virus (BTV) diagnostic tests were evaluated for use in free-ranging bighorn sheep. We sampled one bighorn sheep population four times between 1989 and 1995. The tests evaluated included virus isolation (VI), polymerase-chain reaction (PCR), serum neutralization (SN), agar-gel immunodiffusion (AGID), and competitive enzyme-linked immunosorbent assay (c-ELISA). The c-ELISA, AGID and SN tests had high levels of agreement in determining serogroup exposure in bighorn sheep. We used maximum-likelihood algorithms to estimate the parameters of each diagnostic test used. Although the c-ELISA and AGID had high sensitivity and specificity, the SN had perfect specificity but lower apparent sensitivity. Due to the potential of cross-reactions among multiple serotypes, results of the SN must be interpreted with caution when assessing serotype exposure in an area where multiple serotypes are endemic. The PCR assay delineated convalescent antibody titers from more-recent infections, and consequently, was pivotal in distinguishing a different exposure pattern between the bighorn sheep and cattle in an adjacent herd. Based on an increasing seroprevalence (50% to 100%), BTV circulated through this bighorn sheep population between 1989 and 1993. This increase in seroprevalence coincided with a bighorn die-off due to BTV infection in June, 1991. An adjacent cattle herd was sampled in 1995 for comparison. The bighorn sheep and adjacent cattle had different patterns of exposure to BTV between 1994 and 1995. There was no evidence that BTV circulated through the bighorn sheep population from 1994 to 1995. In 1995, seroprevalence to BTV decreased to 72%, none of yearling bighorn was seropositive, and all of the 39 bighorn sheep were PCR-negative. In contrast, all adult cattle were seropositive to BTV by c-ELISA and SN, and 4 of the calves were seropositive; 11 of the 24 cattle were PCR-positive, including all five calves. Overall, the pattern of temporal herd immunity in the bighorn sheep appeared to follow a classic epidemic curve, with the appearance and subsequent disappearance of herd immunity coinciding with the 1991 die-off in this population. As low levels of herd immunity and high proportions of susceptible animals are key factors in the development of epidemics, this population of bighorn sheep may be at increased risk for a BTV epidemic in the future.     

Rapid enzyme-linked immunosorbent assay for detecting antibodies to canine parvovirus

A rapid screening assay for determining antibodies to canine parvovirus in dog serum using monoclonal antibodies and enzyme-linked immunosorbent assay (ELISA) technology was developed. The ELISA could be read visually, and the results correlated well with serum neutralization (SN) and hemagglutination inhibition (HI) titers. Sera with SN less than or equal to 1:4 or HI less than or equal to 1:10 had an 87.9% correlation with ELISA and sera with SN greater than or equal to 1:64 or HI greater than or equal to 1:80 had a 94.4% correlation. The assay took only 10 to 15 minutes to perform and did not require specialized equipment. The ELISA should be useful in monitoring dogs for the presence of maternal antibodies against parvovirus and for determining seroconversion after vaccination.     

Comparison of diagnostic tests for the detection of equine infectious anemia antibody

Two diagnostic tests are approved for detecting antibody to equine infectious anemia virus: the agar-gel immunodiffusion (AGID) test and the competitive enzyme-linked immunosorbent assay (ELISA). A total of 420 sera from National Veterinary Services Laboratories check sets were tested with the AGID and competitive ELISA. A 100% correlation was obtained. The AGID and competitive ELISA were further used to test difficult samples with low levels of equine infectious anemia antibody (weak positives). A third test (Western blot) was also used with these weak positive samples to resolve any discordant results.     

Serological Survey of Veterinarians to Assess the Zoonotic Potential of Three Emerging Swine Diseases in Mexico

We conducted an immunological assay of blood samples taken from 85 swine‐specialist veterinarians attending the Congress of the Mexican Association of Swine Specialist Veterinarians in Mexico in 2011. Serum samples were assayed for Porcine rubulavirus (PorPV), Encephalomyocarditis virus (EMCV) and Leptospira spp. antibodies. Using a hemagglutination inhibition test, we registered 2.3% and 27% seropositivity for PorPV and EMCV, respectively. Using viral neutralization tests, we registered 5.8% and 47% seropositivity for PorPV and EMCV, respectively. For Leptospira spp., we registered a seropositivity of 38.8%. The variables (sex, age, years of exposure, number of visited farms, biosecurity level and region) showed no significant effect (P > 0.05) on the seropositivity for EMCV, PorPV and Leptospira spp. except for number of visited farms on HI seropositivity for EMCV (P < 0.05; odds ratio: 1.38). The data obtained provide information on the epidemiology of emerging diseases with zoonotic potential in occupational risk groups.