Zoonoses: public health issues with keeping animals or eating them
Zoonoses can become major public health threats if they become uncontrolled. Martin Shakespeare looks at the factors that can lead to unexpected zoonotic disease outbreaks and how they can be controlled
See also Veterinary pharmacy resources
Zoonoses are diseases and infections that are transmitted naturally between vertebrate animals and man. The transmission can occur by a variety of routes: direct contact with animals or infected material (such as blood, faeces or urine) or by aerosol, bites or ingestion of infected or contaminated produce (eg, meat, milk or other foods).
Uncontrolled zoonotic disease poses a massive public health threat, with brucellosis, tuberculosis and other serious zoonoses being historically major causes of illness and death in the UK. Large outbreaks in past decades have influenced current controls through the recommendations of public inquiries and an identified need for better practice.
Control measures, therapeutic advances and best practice for animal owners (both for pets and commercial animal enterprises) have led to a massive reduction in the health burden associated with these diseases.
However, changes in husbandry practice and a widening of the variety of species kept as pets can lead to unexpected outbreaks. For example, the emergence of bovine spongiform encephalopathy in cattle and new variant Creutzfeldt-Jakob disease in humans is linked to changes in feed processing and butchery practice.
And the recent outbreak of Q fever in The Netherlands followed a repositioning of the Dutch dairy industry from cattle to milking goats, associated with a lack of understanding of a need for changes in associated husbandry measures.
The trend for keeping exotic animals as pets can also lead to unexpected disease, with reptiles being now recognised as a major source of unusual salmonella infections.
The control of disease in commercial animal enterprise is based on risk-management through the Hazard Analysis Critical Control Points process. This is underpinned by statutory requirements from the Health and Safety Executive, Department for Environment, Food and Rural Affairs, and the Food Standards Agency. The “Farm to fork” initiative focuses on safeguarding the general public from the risks associated with food, and ensures that quality and safety are maintained.
Control measures provide protection in depth, with good hygiene, herd testing, culling of diseased animals, vaccination and therapeutic intervention all ensuring that milk is safe and that animals go to slaughter in the best condition possible. Slaughter controls and carcass inspection, coupled with good butchery, refrigeration and sell-by dates, ensure consumer protection up to the retailer-consumer interface for meat.
The food processing, retailing and restaurant trades are bound by public health measures that ensure the products they deliver should be safe. Breakdown of best practice or compromise of control can lead to outbreaks of food-borne zoonoses, such as the Escherichia coli outbreak in Wishaw in 1996, with 496 suspected cases, 272 confirmed cases and 21 deaths. Another outbreak of E coli in Wales in 2005, traced to school catering, infected 157 children, one of whom died.
Risks and hazards
Farmers and livestock workers are usually well informed about the hazards they must face and control, especially given the protection measures. However, this is not always true for pet owners, who are either ignorant of, or choose to ignore, the risks that can be associated with their animals.
There is also a lack of understanding and education related to the risks posed by zoonotic disease in adults and children who come from predominantly urban areas. Disease outbreak may also occur at petting farms, zoos and other places where they come into contact with animals, without recognition of the profound need for good hygiene.
There is a need for the gap between veterinary care and traditional GP-led community services, where there may be little linkage between the pet and the patient, to be bridged. The problem of health education relating to zoonotic disease is an issue that must be grasped to protect the health of all.
Individually, members of the general public are responsible for ensuring their own health, and they often require education and information to assist them to understand the risks and benefits of pet ownership and make informed choices.
General advice is available from a wide variety of sources (Government departments, animal charities and other bodies), many of which provide online advice or information leaflets. This is an important field of health promotion, where pharmacists are well placed to be effective advocates for both patients and their pets, signposting their customers to appropriate resource.
It is important that pharmacists should consider rapid referral of any patient suspected of having a zoonotic condition to a doctor as soon as is practicable because most of these conditions will not respond to self-medication.
Citation: The Pharmaceutical Journal URI: 11071312
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