BACKGROUND: Mycobacterium avium subspecies paratuberculosis is the cause of a common disease in dairy herds. Early diagnosis of paratuberculosis infection can improve Johne’s disease control programs.OBJECTIVES: This study aimed to compare the sensitivity, and specificity to methods; blood serum ELISA and stool Nested-PCR for the detection of Mycobacterium avium subspecies paratuberculosis infection in dairy cattle.METHODS: A commercial ELISA kit was used to perform the absorbed ELISA test, which was conducted after exposing serum samples to Mycobacterium phlei antigens to limit cross-reactions. Nested-PCR test was performed using nucleotide sequences related to specific MAP gene fragments, i.e. IS900.RESULTS: As a result of the ELISA antibodies kit, out of the total 2203 serum samples, 112 samples were positive (5.08 %) and 2091 samples were negative (94.92 %). The results of Nested-PCR tests of rectal feces showed that out of 59 cows with the positive results in serum ELISA, 47 (79.66 %) samples were positive and 12 (20.34 %) samples were negative. Moreover, out of 31 cattle with a negative result on the ELISA test, 15 (48.38%) and 16 cattle (51.62 %) had positive and negative results, respectively, on the nested PCR tests of the feces samples.CONCLUSIONS: Due to the low sensitivity of PCR compared to ELISA, the positive and negative predictive values, and the accuracy of ELISA test, as well as the high cost and time-consuming nature of PCR and the need for more and more complex facilities than ELISA, the authors concluded that ELISA is a more suitable method for screening and epidemiological studies than PCR.

BACEKGROUND: Toxoplasmosisis one of the most important zoonotic diseases in Iran and the world. OBJCTIVES: Due to the high consumption of lamb meat and the high frequency of Toxoplasma infection in sheep in Iran, the aim of study was to determine frequency of Toxoplasma infection in the slaughtered sheep of Mashhad area. METHODS: In order to do this study, from summer 2015 to spring 2016, 25 blood and 25 heart muscle samples were seasonally collected from Torghabae slaughterhouse in Mashhad area. The samples were transferred to parasitology laboratory. First, the blood samples were centrifuged and the serum samples were isolated, then a portion of the heart muscles sample was taken for PCR examination. The sera and muscles samples were kept at -20 ºC in freezer until examination time. The sera samples were examined to detect antibody against T.gondii by ELISA method. DNA of heart muscle was extracted by commercial extraction kit and was examined to detect Toxoplasma DNA by nested –PCR. RESULTS: In the present study, of 100 sampled sheep, only 1 (1%) of the serum samples was seropositive, while 22 (22%) of the DNA samples were PCR positive. In this study, the highest frequency of Toxoplsma PCR-Positive was seen in spring and the lowest in summer in sheep. Also, the result of this study showed that the agreement between the molecular and EISA method was “fair”. CONCLUSIONS: Based on the high frequency of Toxoplasma infection in heart muscle of sheep, it seems that the risk of transmission of Toxoplasma infection from sheep meat is high.

BACKGROUND: Over the recent years, Neospora caninum has been one of the most important causes of abortion in dairy cattle. OBJECTIVES: We conducted the present study in order to investigate the seroprevalence of N. caninum in dairy cattle in Semnan province and its effect on abortion. METHODS: 237 blood samples were obtained from various Semnan dairy farms and 104 bulk dairy samples from four milk collection centers in Semnan, Garmsar, Damghan, and Shahrood were tested for sera and milk utilizing ELISA (Svanova Biotech AB) test kits. RESULTS: The results revealed that 87.27 % of bovine serum was positive. The percentage of opacity density (OD) of positive sample (PP) ranged from 72.17 to 137.3 (114.21±24.65). In addition, the average rate of milk seroprevalence to the parasite was 95.23 % in Semnan province. CONCLUSIONS: The frequency of Neospora caninum infection in blood and milk was high in Semnan, yet no significant relationships were observed with abortion (p < /em>>0.05).

BACKGROUND: Toxoplasma gondii is a zoonotic obligate intracellular protozoan parasite that infects all warm-blooded animals as well as human worldwide. Human is infected with Toxoplasma parasites by eating half-cooked meat of livestock or oocyte. OBJECTIVES: The purpose of this study was to determine the presence of Toxoplasma in aborted fetuses of sheep using the serological method in North Khorasan province. METHODS: In this study, from 2015 to 2017, 133 samples of the thoracic fluid in aborted fetuses of sheep from different cities of North Khorasan Province were collected and sent to the central laboratory of Bojnourd. For each sample, a questionnaire was prepared for gathering information such as age and city, and then, the antibody level was determined in each sample by ELISA method. RESULTS: In this study, the age of 133 aborted fetuses of sheep was more than 120 days. Also, of the 133 aborted fetuses of sheep, 14 samples (10.53%) were infected with Toxoplasma parasites. The highest and lowest rate of Toxoplasma infection was observed in 2016 and 2017, respectively. Also, the most infection was found in Shirvan and Faroj cities. Results of chi-square test showed that there was a significant difference between year and abortion in sheep due to infection with Toxoplasma parasite (P<0.05). There was not significant difference between the frequency of this parasite infection and aborted fetuses in different areas (P> 0.05). CONCLUSIONS: The results of this study indicate that Toxoplasma gondii infection is one of the causes of abortion of sheep in North Khorasan province, and sheep is one of important sources of meat and dairy products in this area, Therefore, observance of public health tips and the complete cooking of meat and boiling milk is emphasized.

BACKGROUND: Aflatoxin M1 (AFM1) is the main monohydroxylated derivative of aflatoxin B1 (AFB1) formed in liver and excreted into milk. AFM1  creates  certain hygienic risks for human health. OBJECTIVES: The aim of this study was to determine AFM1 level in raw milk samples in Yazd province. METHODS: This investigation was a descriptive-cross sectional study. Eighty raw milk samples were collected from four cities (Yazd, Taft, Mehriz and Sadogh) in Yazd province in winter and spring seasons. The concentration of AFM1 was determined by ELISA method. The analysis of the results was performed using ANOVA and Chi-square tests. RESULTS: All samples (100%) were contaminated with AFM1, with the concentrations ranging from 3.18 to 92.24 ng/l with a mean concentration of 22.07 ng/l. AFM1 level in 13.7% of raw milk samples was higher than the maximum tolerance limit of 50 ng/l accepted by the European Union (EU). The contamination level of AFM1 in winter samples (28.21 ng/l) was higher than spring samples (15.92 ng/l). Also, the highest and lowest contamination levels were observed in milk samples collected from Sadogh (mean 42.21 ng/l) and Yazd (12.79 ng/l) cities, respectively. CONCLUSIONS: Results demonstrated AFM1 was detected with a mean concentration of 22.07 ng/l in milk samples of Yazd province. Moreover, 13.7% of samples contained AFM1 at hazardous levels for human health.

BACKGROUND: Equine arteritis virus (EAV) causes respiratory disease, abortion and sometimes, neurological signs. Stallions which are permanently infected with the virus, are the constant carriers of the virus in their semen and transmit the virus to other horses through sexual contact. OBJECTIVES: The aim of this study was to evaluate EAV infection in horses in four provinces of Iran and its relationship with age, sex, and race. METHODS: Blood samples were taken from 149 horses with different sex, age and race with history or clinical signs associated with equine viral arteritis, including the manifestation of respiratory disease (fever, nasal secretion, coughing), nervous signs (ataxia, dysmetria, recumbency) and abortion. The commercial ELISA kit was used for viral antibody detection. RESULTS: From 149 sampled horses, 11 cases (7.4%) were found to be positive for EAV. Seropositive cases were recorded in Tehran (2.7%), Golestan (4.3%), Khuzestan (6.7%) and West Azerbaijan (23.8%) provinces. CONCLUSIONS: This survey confirmed the presence of EVAV in horses from four provinces of Iran with the sensitive (98.3%) and special (98.9%) test. Therefore, consideration should be given to the control and prevention programs for the spread of this virus.

Immunoglobulin reactions to Salmonella dublin in serum and milk from 4 groups of lactating cows were measured by an indirect ELISA. The groups consisted of (1) cows that were natural carriers of S dublin in the mammary gland, (2) experimentally infected cows that did not become carriers, (3) cows inoculated with a commercial S dublin bacterin, and (4) cows used as S dublin-negative controls. Milk and serum samples were obtained at monthly intervals. Models for predicting carrier status were developed by use of stepwise logistic regression. Independent variables consisted of serum and milk IgG and IgM titers to S dublin lipopolysaccharide and a ratio of IgG to IgM. The utility of a single sample vs multiple samples obtained at 1-month or 2-month intervals was tested by comparison of goodness-of-fit X2 P values for 8 models predicting carrier status. Immunoglobulin reactions specific to S dublin were a significant predictor of carrier status (P < 0.001). Serum IgG titers specific for S dublin were the most important variable for predicting carrier status. Two serum IgG titers to S dublin obtained 2 months apart was a better predictor of carrier status than measurement of the IgG:IgM ratio from a single serum sample. Immunoglobulin recognizing S dublin epitopes also were detected in milk samples. In milk, performing 2 ELISA 60 days apart to determine IgG and IgM reactions to S dublin appeared to be useful for the prediction of carrier status, but was not as accurate as models for serum immunoglobulin reactions.

The sensitivity of an indirect enzyme-linked immunosorbent assay (ELISA) for bovine IgG serum antibody to Pasteurella haemolytica was compared with that of an indirect hemagglutination (IHA) test. Pasteurella haemolytica serotypes were grown in a chemically defined cell culture medium, and soluble antigens released into the growth medium were used in the ELISA and IHA test. An ELISA with serotype-1 antigen consistently detected antibody in sera that were positive by IHA test (correlation, 99%). Sera reacting with serotype-1 ELISA antigens also reacted with ELISA antigens prepared from other serotypes. Although ELISA titers determined by the 2 methods were approximately linear. Titer increases detected in paired serum samples by either test were similar. The ELISA was more sensitive than was the IHA in detecting colostral IgG antibody in serum of newborn calves. The ELISA uses a simple, stable antigen preparation and detects antibody to P haemolytica serotypes that commonly infect cattle.

Seven hybridomas that secreted monoclonal antibodies (MAB) against the peplomer protein and one that secreted MAB against the nucleocapsid protein of Berne virus (proposed family Toroviridae) were isolated. All MAB directed against the peplomer protein neutralized virus infectivity and, with the exception of MAB 6A7, inhibited each other's binding in competition assays. Neutralization of Berne virus infectivity was potentiated when some MAB were used in pairs. The antibodies have been used to localize toroviral proteins in infected cells; use of antipeplomer MAB 6B10 yielded a diffuse intracytoplasmic immunofluorescence, whereas the antinucleocapsid MAB 1F1 detected antigen in the intra- and perinuclear compartments. By use of radioimmune precipitation, protein A of Staphylococcus aureus was found to bind directly to the nucleocapsid polypeptide, without the requirement for specific antibody. Using fluorescein isothiocyanate-conjugated protein A, the intranuclear accumulation of the nucleoprotein of Berne virus was confirmed by results of immunofluorescence.