Determination of polymorphism of IS-1311 sequence in Mycobacterium avium subspecies paratuberculosis strains isolated...

Area of Science:

• Veterinary microbiology
• Bacteriology
• Molecular epidemiology

Background:

• Mycobacterium avium subspecies paratuberculosis (MAP) causes paratuberculosis, a chronic disease in ruminants.
• Subclinical MAP infections in dairy herds pose a risk for disease transmission.
• Genetic diversity of MAP strains can influence transmission dynamics and host-pathogen interactions.

Purpose of the Study:

• To genetically characterize Mycobacterium avium subspecies paratuberculosis (MAP) strains isolated from milk of apparently healthy cows.
• To investigate the genetic polymorphism of the IS-1311 sequence in MAP strains.
• To determine the prevalence of different MAP strain types within a low paratuberculosis seroprevalence herd.

Main Methods:

• Isolation of MAP strains from pooled milk samples from 310 asymptomatic cows.
• Genetic typing using the Polymerase Chain Reaction - Restriction Enzyme Analysis (PCR-REA) method.
• Analysis of the IS-1311 sequence polymorphism for strain differentiation.

Main Results:

• Two distinct genetic types of MAP were identified: sheep and cattle types.
• The bovine type of MAP was highly prevalent, accounting for 98.5% of the isolated strains.
• MAP strains were detected in milk from cows without apparent disease symptoms or antibodies.

Conclusions:

• The study identified both sheep and cattle genetic types of MAP in milk from a low-prevalence herd.
• The predominance of the bovine MAP type suggests its significant circulation within the studied cattle population.
• These findings highlight the utility of PCR-REA for genetic typing of MAP and emphasize the potential for shedding by subclinically infected animals.