Bovine tuberculosis

Bovine tuberculosis
Y tambe · CC BY-SA 3.0 · source
Name	Bovine tuberculosis
Field	Veterinary medicine, Infectious disease
Symptoms	Fever, weight loss, chronic cough, lymphadenopathy
Complications	Zoonotic transmission, economic losses
Onset	Variable
Duration	Chronic
Cause	Mycobacterium bovis
Diagnosis	Tuberculin skin test, interferon-gamma release assays, culture
Differential	Johne's disease, Pasteurella multocida infections
Prevention	Test-and-slaughter, pasteurization, wildlife control
Medication	Isoniazid, Rifampicin (limited use), antimicrobial therapy
Frequency	Endemic in many regions
Deaths	Agricultural and public health impacts

Bovine tuberculosis is a chronic, progressive infectious disease primarily of cattle caused by Mycobacterium bovis. It affects production animals, wildlife reservoirs, and humans, and has driven large-scale veterinary public health programs in countries such as United Kingdom, United States, New Zealand, and Ireland. Control efforts have involved coordination among institutions like the World Organisation for Animal Health, Food and Agriculture Organization, and national agencies such as the Department for Environment, Food and Rural Affairs and the United States Department of Agriculture.

Overview and Classification

Bovine tuberculosis falls within the Mycobacterium tuberculosis complex alongside organisms implicated in human disease such as Mycobacterium tuberculosis and Mycobacterium africanum, and is classified in bacterial taxonomy under the genus Mycobacterium. Historically, outbreaks influenced policy in the Industrial Revolution era and led to legislation such as measures enacted after investigations by bodies like the Royal Commission on Tuberculosis. Key stakeholders in modern classification and surveillance include the World Health Organization and the European Centre for Disease Prevention and Control which interact with regional authorities such as DEFRA and the Agriculture and Horticulture Development Board.

Etiology and Pathogenesis

The etiologic agent, Mycobacterium bovis, is genetically and phylogenetically related to Mycobacterium tuberculosis complex members identified in historical collections like those at the Natural History Museum, London. Pathogenesis involves inhalation or ingestion of bacilli with subsequent formation of granulomas in pulmonary and extrapulmonary tissues; this immune response invokes cellular actors defined in immunology literature and was characterized in early work by researchers at institutions such as Pasteur Institute and Rockefeller University. Host-pathogen interactions studied at universities including University of Cambridge, University of Edinburgh, and University of California, Davis have informed vaccine research including trials associated with Bacillus Calmette–Guérin.

Epidemiology and Transmission

Epidemiology features multi-host dynamics with transmission among domestic cattle, wildlife reservoirs like European badger populations in the United Kingdom and Ireland, brushtail possums in New Zealand, and cervids such as White-tailed deer in the United States. Outbreak investigations have engaged agencies including the Centers for Disease Control and Prevention and national veterinary services, and surveillance networks involve laboratories within the Veterinary Laboratories Agency and academic centers such as Imperial College London. International trade, movement controls, and historical patterns traced through records in archives like the National Archives (United Kingdom) have shaped spread and control measures.

Clinical Signs and Diagnosis

Clinical presentation in cattle includes weight loss, chronic cough, udder involvement, and tuberculous lesions detectable at abattoir inspection; epidemiologic links are often established by traceability systems operated by authorities such as the Animal and Plant Health Agency. Diagnostic modalities include the single intradermal comparative cervical tuberculin test endorsed by World Organisation for Animal Health, interferon-gamma assays developed with input from laboratories at CSL Limited and research groups at University of Liverpool, and culture with molecular typing using methods standardized by institutions like Public Health England. Historic diagnostic advances trace to researchers like Robert Koch and institutions including the Pasteur Institute.

Control, Prevention, and Eradication Programs

Control strategies combine test-and-slaughter policies, movement restrictions, biosecurity measures on farms promoted by bodies like National Farmers' Union (England) and Irish Farmers' Association, and wildlife management programs implemented by agencies such as the Department of Conservation (New Zealand). Eradication campaigns in countries like United States relied on federal-state coordination through the Animal and Plant Health Inspection Service. Vaccination research involving Bacillus Calmette–Guérin and candidate vaccines has been pursued by consortia including teams at Pirbright Institute and CSIRO. International funding, policy guidance, and trade implications engage organizations such as the World Bank and the European Commission.

Public Health and Zoonotic Impact

Zoonotic transmission to humans, historically significant in outbreaks documented in urban centers like London and metropolitan areas monitored by the Centers for Disease Control and Prevention, occurs via unpasteurized milk, aerosol exposure, and direct contact; this prompted milk pasteurization policies championed by public health campaigns and regulatory bodies like the Public Health Agency of Canada. Human cases are clinically similar to Mycobacterium tuberculosis infection and require coordination between clinical services at hospitals such as St Thomas' Hospital and public health units for contact tracing. Global health initiatives by the World Health Organization and One Health collaborations involving World Organisation for Animal Health and Food and Agriculture Organization emphasize integrated surveillance, risk communication, and research funding from philanthropic entities such as the Wellcome Trust to mitigate zoonotic impact.

Category:Zoonoses