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Quantitative real-time PCR and culture examination of Mycobacterium avium subsp. paratuberculosis at farm level
Shahram Hanifian1, Sajjad Khani, Abolfazl Barzegari
1Department of Food Science and Technology, Faculty of Agriculture Science, Tabriz Branch, Islamic Azad University, Tabriz, Iran. hanifian@iaut.ac.ir
Abstract:
Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease in ruminants and may contribute to Crohn's disease in humans. The aim of this study was to determine the occurrence and quantity of MAP in cattle feces and milk in the Iranian context. In addition, we evaluated the effect of cattle age as well as farming system as risk factors contributing to MAP load. For this, a total sample of 373 consisting of 150 cattle feces (CF), 150 individual cow's milk (ICM), as well as 73 bulk-tank milk (BTM) was collected randomly and regardless of the cattle health status. The samples were assayed using F57 quantitative real-time PCR (qPCR) and culture method. According to the results of qPCR which was found ≈ 10 times more sensitive than culture assay, MAP was detected in 68.66% (103/150) of the CF, 12% (18/150) of the ICM and 52.05% (38/73) of the BTM samples. In contrast to the previous reports, the quantity of MAP in the BTM (2.03-5.97 log cfu/50 ml) was statistically (p<0.01) higher than the ICM (0.90-1.97 log cfu/50 ml). Data suggested a direct relation (p<0.01) between the cattle age and the quantity of MAP in the CF samples, while the relation was not statistically significant (p>0.05) for the ICM. In addition, MAP load in the BTM samples obtained from traditional farms was significantly (p<0.01) higher than that of the industrial ones, while the differences in CF and ICM was not significant (p>0.05).
Insights
Mycobacterium avium subsp. paratuberculosis (MAP) is prevalent in Iranian cattle feces and milk. Cattle age and traditional farming systems significantly increase MAP load, highlighting potential public health risks.
Area of Science:
- Veterinary Microbiology
- Food Safety
- Epidemiology
Background:
- Mycobacterium avium subsp. paratuberculosis (MAP) is an important veterinary pathogen causing Johne's disease in ruminants.
- MAP infection in cattle is a potential source for human exposure and has been implicated in Crohn's disease.
- Understanding MAP prevalence and load in cattle is crucial for risk assessment and control strategies.
Purpose of the Study:
- To determine the occurrence and quantity of MAP in cattle feces and milk in Iran.
- To investigate the influence of cattle age and farming system on MAP load.
Main Methods:
- Samples included 150 cattle feces (CF), 150 individual cow's milk (ICM), and 73 bulk-tank milk (BTM).
- MAP detection and quantification were performed using F57 quantitative real-time PCR (qPCR) and culture methods.
- qPCR demonstrated higher sensitivity compared to culture assays.
Main Results:
- MAP was detected in 68.66% of CF, 12% of ICM, and 52.05% of BTM samples.
- MAP quantity was significantly higher in BTM than ICM (p<0.01).
- Cattle age correlated positively with MAP quantity in CF (p<0.01), and traditional farming systems showed higher MAP loads in BTM (p<0.01).
Conclusions:
- MAP is widespread in Iranian cattle populations, with significant presence in feces and milk.
- Cattle age and traditional farming practices are identified as key risk factors for increased MAP load.
- Findings emphasize the need for enhanced surveillance and control measures to mitigate MAP transmission and potential human health risks.
