Issues in foot and mouth disease
Foot and mouth disease has gripped Britain since the end of February. Clare Bellingham examines the pharmaceutical issues
Foot and mouth disease was first confirmed in the current outbreak on February 19. Since then, a fight has been on to contain the disease. Along with slaughtering animals, isolating areas and placing transportation restrictions on animals, disinfectants have been a key weapon in controlling the spread of infection. The massive demand for disinfectants has put a strain on farmers' usual supply routes and pharmacists in rural areas are being approached by farmers for alternatives. Reports in the national press last week suggested that some farmers are becoming so desperate for disinfectant that they have resorted to using toilet cleaner. Pharmacists have widespread support, including that of the Ministry of Agriculture, Fisheries and Food (MAFF), in providing disinfectants. The more outlets there are for such products the better.
The disease and preventing its spread
Foot and mouth disease is a viral infection. The current British outbreak is caused by a pan-Asia type O virus, first identified in the early 1990s. The disease affects cloven-hooved animals, including pigs, cattle and sheep. The virus causes an increase in temperature and the development of small sores in the mouth and feet which result in a loss of appetite and lameness. Dairy cattle are the most seriously affected and suffer lower milk yields. The disease is rarely fatal, except in very young or weak animals, although some animals do suffer complications, such as infected lesions. After two or three weeks of illness, most animals recover naturally.
Foot and mouth disease is unrelated to the human condition hand, foot and mouth disease. The chances of foot and mouth disease affecting humans is remote. It is thought that the only possible route of infection would be through direct contact between an infected animal and an open wound. The Food Standards Agency says that there is no risk to humans by consuming meat or milk from infected animals. However, even if humans do catch foot and mouth disease, the illness is mild and not life-threatening.
Foot and mouth disease has economically disastrous outcomes for farming. If a country has foot and mouth disease, it cannot export meat for many years after the infection. And the disease reduces the productivity of animals resulting in lower meat and dairy yields. In today?s intensive farming culture, these outcomes are unacceptable in economic terms. It is for this reason that the mass slaughter of animals seen over the past few weeks has taken place.
Foot and mouth disease is caused by seven strains of virus. It is endemic in some parts of the world, particularly less developed countries. Britain has been disease-free for many years and, while the source of the virus causing the current outbreak is unknown, it is thought that it entered the country in imported meat, despite the fact that it is illegal to import meat from infected areas.
The virus can live for up to a month. It thrives in cold, dark and chemically neutral environments. Heat, humidity, sunlight, acid and certain disinfectants destroy it.
The virus is spread by mechanical transfer but it is also an airborne disease and is reported to be able to travel for up to 100 miles on the wind. Anything can mechanically transfer the virus other animals, shoes, clothing and vehicles. The Royal Pharmaceutical Society and the National Pharmaceutical Association (NPA) say that pharmacists should advise the public to stay away from farmland and to avoid activities that may increase the risk of spreading the virus.
Isolating areas with suspected outbreaks helps to prevent airborne spread of the disease and disinfectant barriers are used to prevent mechanical spread.
Pharmacists should be able to advise on use of appropriate disinfectants in infected areas, according to the Society and the NPA.
A list of approved disinfectants for foot and mouth disease is available on the MAFF website. A spokeswoman for MAFF said that pharmacists should only supply approved products. In addition, pharmacists need to be able to advise on the appropriate dilution of each disinfectant. This information is also given on the MAFF website. If farmers had any concerns about using disinfectants, they should be referred to local MAFF contacts, the MAFF spokeswoman added.
The Veterinary Pharmacists Group recommends the use of peroxide-type disinfectants because they are easy to dispose of. Approved examples include Blitz, Formalin BP, and Sorgene 5. The disinfectant should be changed daily or more frequently if it becomes heavily soiled, the group advises.
The disinfectant most readily available to pharmacists is Formalin BP (containing not less than 34 per cent formaldehyde) which, according to the MAFF, should be diluted one part disinfectant to nine parts water.
Further advice can be obtained from the national foot and mouth disease helpline (tel 0845 050 4141) or the NPA's information department.
Vaccinating against foot and mouth disease may seem an obvious solution but there are several associated problems. Most importantly, vaccines cannot be used under European Union policy.
The vaccines are not completely effective. Seven strains of the virus exist and this makes it difficult to give complete vaccine cover. In addition, frequent administration of the vaccine (an inactivated, dead preparation) is needed (twice a year).
There is a danger that the animal receiving the vaccine will get the disease or become a carrier of the virus, a condition which can persist for up to two years, according to Dr Tony Little (vice president, British Veterinary Association). There have been a number of outbreaks caused by vaccination where the virus had not being inactivated properly, he says. It is also difficult for tests to distinguish between infected and vaccinated animals.
The Institute for Animal Health houses an international vaccine bank holding half a million doses of each of the strains of foot and mouth disease. Although Britain does not vaccinate animals against foot and mouth disease, this bank of vaccines is held in case it is decided in an emergency to use vaccination to help to control an outbreak of foot and mouth disease. However, if a country accepts that it has foot and mouth disease in its herd and uses vaccination to prevent disease spread, meat from that country cannot be exported to disease-free countries. There is no point in vaccinating non-food chain animals that might be carrying the disease, Dr Little said. Better vaccines may be developed in the future, but experts believe that they are a long way off. A major problem is gaining funding for research into vaccines that are not used.
Meanwhile, the nation waits to see whether or not the precautions taken over the past few weeks have controlled the current outbreak of foot and mouth disease.
©The Pharmaceutical Journal
Citation: The Pharmaceutical JournalURI: 20004124
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