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Tuberculosis Pathogen of Human and Animals

#3219.2


The Molecular-Genetic Polymorphism of Tuberculosis Pathogen of Human, Cattle, Pigs and Poultry and Studying of Channels of Infection in Live Farming

Tech Area / Field

  • AGR-DIS/Disease Surveillance/Agriculture
  • BIO-CGM/Cytology, Genetics and Molecular Biology/Biotechnology
  • BIO-MIB/Microbiology/Biotechnology

Status
8 Project completed

Registration date
01.11.2006

Completion date
11.12.2012

Senior Project Manager
Genisaretskaya S V

Leading Institute
Federal Centre of Toxicological and Radiation Safety of Animals, Russia, Tatarstan, Kazan

Supporting institutes

  • Central Tuberculosis Research Institute, Russia, Moscow

Collaborators

  • Canadian Food Inspection Agency / Mycrobacterial Diseases Centre of Expertise, Canada, ON, Ottawa

Project summary

Unfavorable epidemic situations for TB have been reported worldwide, for both developed and developing countries. Increasing numbers of TB incidence have been reported in many countries.

Similar TB situations are observed in cattle populations. TB of cattle causes significant economical damage to cattle farming and also represents a threat to human health. M. tuberculosis can as well persist in the humans as in the animals, and the disease may be transmitted in two directions – from humans to animals and back.

As in other countries, our specialists use epizootologic and clinical diagnostic methods, but the main antemortem method of TB diagnosis in cattle is the tuberculin skin test. However, diagnosis of TB in cattle based on allergic tuberculin skin test reaction is becoming insufficient. At a more advance stage of the disease allergic reactions are not express. Humoral response will be present during latest stages of the disease. Diagnosis of TB is further complicated because animals may harbour other non-tuberculous mycobacteria. A positive tuberculin skin test is followed by slaughter of the animals followed by postmortem examination and laboratory studies of biological materials in order to exclude or confirm the diagnosis.

Usually tuberculosis is confirmed by laboratory methods: bacteriology studies – using microscopy and culture on medium, and with biological test – reproduction of TB in guinea-pigs. Each method has significant disadvantages.

It is imperative to develop and implement new methods to detect and identify mycobacteria. New methods should significantly reduce time of postmortem diagnosis of the disease and exclude false reactions in tuberculin skin testing due to para-allergic reactions in animals sensitized by non-tuberculous mycobacteria or other agents.

The most effective method of mycobacteria detection, with the highest specificity and sensitivity, is polymerase chain reaction (PCR). It allows not only the detection the pathogenic organism but also the identification of species by genetic markers. Currently several amplification systems for different genomic regions of M. tuberculosis, M. bovis, M. avium sp. have been described.

The goal of the investigation: to establish an understanding of development of epidemics and epizootics of bovine, human and avian TB and paratuberculosis based on molecular and epidemiologic studies of farms with adverse TB situations in the Tatarstan Republic.

The main objectives are:

  1. To analyze TB among humans and animals in large farms with high incidence of TB situation and select several farms as experimental models in the Tatarstan Republic.
  2. To isolate mycobacterial strains from cattle, pigs, poultry and maintenance staff of cattle farms, identify strains using microbiology and biochemistry methods, and perform drug susceptibility testing, to establish and maintain a collection of isolated mycobacterial strains.
  3. To study genome polymorphisms of MTBC, M. avium ssp. strains isolated from patients and animals (cattle, pigs, poultry).
  4. To conduct molecular and epidemiological research into tracing transmission pathways of MTBC, M. avium ssp. including paratuberculosis strains in farms among contact staff and animals.


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