Serological, cultural, and molecular analysis of Brucella from Buffalo milk in various regions of Iran.

Brucellosis is a significant infection that causes abortion, decreased milk production, and sterility in livestock, which greatly affects the industry. This study aimed to determine the prevalence of Brucella in buffalo milk samples across various regions of Iran, utilizing serological, molecular, and cultural analyses. A total of 1860 buffalo milk samples were collected from industrial, semi-industrial, and traditional buffalo farms in four major buffalo breeding provinces. The milk ring test agglutination test (MRT) was initially conducted on all milk samples, followed by culture and molecular testing for positive and negative samples in MRT. The study revealed positive results for the presence of Brucella DNA in various provinces of Iran. The MRT had a relatively low sensitivity, with results ranging from 0 to 0.7% in different provinces. However, the AMOS PCR method showed a significantly higher presence of Brucella DNA, ranging from 13 to 46% in these provinces. The highest abundance of Brucella bacterial DNA was found in Ardabil province, while the lowest was in West Azerbaijan province. Brucella abortus was the most commonly detected bacteria, followed by Brucella melitensis. Interestingly, the B. abortus vaccine strain RB51 was detected in 26.3% of positive samples of B. abortus. The culture assay of milk samples further confirmed the presence of B. melitensis biovar 1 in one sample from Khuzestan province. Overall, the study emphasizes that the AMOS PCR method is the most sensitive in detecting Brucella-exposed milk, while the sensitivity of milk sample culture and MRT is relatively lower.

Evaluation of foot and mouth disease (FMD) vaccine using registered surveillance data.

Foot and mouth disease (FMD) is a highly contagious transboundary disease of cloven-hoofed animals. In Iran, the disease is endemic with outbreaks occurring throughout the year. Mass vaccination of domestic ruminants has been adopted as a preventive strategy. A study was conducted to evaluate the effectiveness of currently in use FMD vaccines using official disease surveillance data. Surveillance data of FMD outbreaks and vaccination in cattle farms from January 2017 to March 2019 was obtained from the Iranian Veterinary Organization (IVO). A case-control study comprising 190 laboratory-confirmed cases and 380 randomly selected controls, frequency-matched by location and production type, was performed to estimate vaccine effectiveness (VE) of vaccines in industrial and semi-industrial farms. Multivariable logistic regression was used to estimate odds ratios based on brand of vaccine, time since vaccination, and within-farm vaccination coverage. A total of 2297 outbreaks occurred during the study period with majority (75%) reported from village epi-units. Only 38% of industrial and semi-industrial farms recorded vaccination during the studied period. Vaccination was effective against clinical disease with the highest VE observed in farms vaccinated with commercial vaccine brand A (VE = 0.90%, 95% CI 0.79-0.96), vaccinating > 94% of herd population (VE = 0.77%, 95%CI 0.54-0.98) and in < 35 days after vaccination (VE = 0.56%, 95% CI 0.04-0.8). The current high-potency vaccines confer medium protection in investigated cattle farms. The high occurrence of the disease in village epi-units and low coverage of vaccination in industrial and semi-industrial farms will contribute to maintenance and circulation of the virus in the susceptible population.

Identification at biovar level of Brucella isolates causing abortion in small ruminants of iran.

To determine the most prevalent biovar responsible for brucellosis in sheep and goat populations of Iran, a cross-sectional study was carried out over 2 years in six provinces selected based on geography and disease prevalence. Specimens obtained from referred aborted sheep and goat fetuses were cultured on Brucella selective media for microbiological isolation. Brucellae were isolated from 265 fetuses and examined for biovar identification using standard microbiological methods. Results showed that 246 isolates (92.8%) were B. melitensis biovar 1, 18 isolates (6.8%) were B. melitensis biovar 2, and, interestingly, one isolate (0.4%) obtained from Mazandaran province was B. abortus biovar 3. In this study, B. melitensis biovar 3 was isolated in none of the selected provinces, and all isolates from 3 provinces (i.e., Chehar-mahal Bakhtiari, Markazi, and Ilam) were identified only as B. melitensis biovar 1. In conclusion, we found that B. melitensis biovar 1 remains the most prevalent cause of small ruminant brucellosis in various provinces of Iran.