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Foot and mouth disease: consequences for public health 

Occurrence - Foot and mouth disease (FMD) is a disease that is endemic in many countries, including much of Africa, Asia, and South America. It affects all cloven-hoofed animals and is the most contagious of animal diseases. In animals the disease presents with acute fever, followed by the development of blisters chiefly in the mouth and on the feet. Infected animals secrete numerous virus particles before clinical signs appear.

Infectious agent - It is caused by a virus of the family Picornaviridae, genus Aphthovirus, of which there are different serotypes:O, A, C, SAT1, SAT2, SAT3, and Asia1. The current outbreak in countries in the European Union is due to the highly virulent pan-Asiatic serotype O.

Identification in humans - Although FMD may affect humans, its occurrence is quite rare and the human disease is benign. Given the high incidence of the disease in animals, both in past and recent outbreaks worldwide, the FMD virus has been isolated and typed in not more than 40 patients during the last century, and one case was an asymptomatic infection. The type of virus most often isolated in humans is type O followed by type C and rarely A.

Symptoms: These have been mostly mild and self-limiting - mainly uncomfortable tingling blisters on the hands but also fever, sore throat, and blisters on the feet and in the mouth and tongue. Patients have usually recovered a week after the last blister formation.

Mode of transmission in humans - The circumstances in which it occurs in humans are not well defined, though all reported human cases have had close contact with infected animals or drank raw milk from infected cows. In 1834, in Hertwig, Germany, three veterinarians self-infected themselves by drinking 250 ml of milk from infected cows on four consecutive days. The three men developed clinical manifestations. There is no report of infection from pasteurized milk, and it is generally accepted that FMD has no implications for the human food chain.

Incubation period - The incubation period in humans is 2-6 days.
Person-to-person spread has not been reported. Suspected and confirmed human cases must have no contact with susceptible livestock to avoid transmitting the disease to animals.

Diagnosis - FMD should not be confused with the human disease hand, foot, and mouth disease. This is an unrelated and usually mild viral infection, principally of children, caused by different viruses, primarily coxsackie A virus. The disease can also be confused with herpes simplex and sometimes vesicular stomatitis.

Laboratory diagnosis Criteria for establishing a diagnosis of FMD in humans are the isolation of the virus from the patient and/or identification of specific antibodies after infection. Laboratory tests for diagnosis of human FMD are the same as for animals.

Control of FMD in humans Prevention of the disease in humans consists mainly of controlling the disease in domestic animals. However, wounds or abrasions of persons in contact with sick animals or with contaminated materials should be protected and milk should be pasteurized or boiled.

Control of FMD in animals Control requires close collaboration between veterinary, health, and local authorities.

The highest risk to European Union countries comes from providing food to animals in these countries from legal and illegal imports of infected live animals and from contaminated meat or dairy products from infected countries. International travellers bringing back food from endemic countries could also spread the disease.

The FMD virus can survive for long periods in a range of fresh, partially cooked, cured, and smoked meats and in inadequately pasteurized dairy products. Spread of the virus is facilitated by the development of long distance animal trading. Dense livestock populations may also enhance local spread in the vicinity of an outbreak.

Awareness of the disease among livestock owners is crucial, as are good diagnostic facilities. Spread can take place on the wind and mechanically by the movement of animals, people, and vehicles that have been contaminated with the virus. Thus the whole population has a role in combating the disease. Restriction of non-essential movement both into and out of affected farms and more widely in the countryside is important.

Non-microbiological hazards which may be associated with a major outbreak of FMD and the destruction of large numbers of animals - Hazards to public health may also originate from carcass disposal and use of disinfectants. Pyres for carcass incineration are a distressing sight for the public, the smell is unpleasant and they may put people at risk by creating traffic hazards. However, the main risk to the public is likely to come from smoke, causing breathing difficulties in people with respiratory disease. Burning of carcasses also generates dioxins and residual organic material, polyaromatic hydrocarbons from burning creosote-treated wooden sleepers. During the control of FMD outbreak in animals, the use of large quantities of disinfectant may lead to contamination of ground water and subsequent ill-health resulting from its consumption.

In addition, people may suffer from certain mental health disorders, resulting from the mass slaughtering and destruction of animals carried out as part of the disease control measures and of the economic losses associated with these.

 

More information on FMD

 

 

 

 

 

 

 

 

 

       WHO/OMS  |  Acknowledgements