Foot and mouth is highly contagious viral disease of cloven hoofed animals cattle, buffaloes, pigs, sheep, goats, and deer caused by a virus. The disease has been eradicated in North America and in European countries New Zealand, Australia by following stringent eradication measures. But it still exists in several countries of Asia, Middle East, and South America. For livestock trade this is the major constraint. The mortality in adult animals is very less but in calves it is very high. Even though adult animals recover they become poor producers and also become lame due to hoof damage. In cattle the skin coat is discolored and the animal gets respiratory distress if they work in sun. Therefore in as much animals lose their milk production and also ability to work causing severe economical loss to the herds men.
The disease is caused by a virus and there are several serotypes of identified viruses. So far seven main serotypes are identified and nearly sixty sub serotypes in each group. O, A, C, Sat 1, Sat 2, Sat 3 and Asia 1 are the main serotypes. Serotype O is the identified virus in many countries.
The disease is fast spreading type and as such fast and stringent methods are to be followed to control the disease. However vaccination is the only best choice to control the disease. Vaccination with polyvalent vaccine should be used for getting complete protection all the strains. The immunity is also of short duration. As such vaccinations should be repeated every 6 months. Crossbred animals are highly susceptible and they should be protected with polyvalent vaccine for every three months.
Transmission of the virus:
Animals get infection from the nasal discharges, saliva, milk, urine, expelled air, fecal matter and semen. Animals also get infection through aerosol infection. The virus is also present in large quantities in the vesicles at the time of rupture. The virus comes out through the saliva. The virus can spread through air. Airborne infection is common and as such the viral infection very rapidly from place to place. Calves get infection from suckling milk from infected animals. The incubation period in cattle is about two weeks and it varies from species to species. The incubation period is shorter in pigs and they get the disease symptoms in two days and sometimes it may be as shorter as 18-24 hours.
The disease starts with fever and appearance of vesicles in the mouth, feet and on the udder. The vesicles also sometimes appear inside of the thighs and on the teats. The vesicles soon rupture and wounds are seen.
The animal will become lame due to pain of the feet. The wounds on the feet will become bigger if not attended properly they are infested with maggots. Animal feels lot of discomfort to wave away the flies and due to pain.
The mouth lesions also enlarge and the wounds on the tongue become bigger and the superficial layer will be peeled and the animal suffers very much. Profuse stingy salivation and nasal discharges are seen.
In pregnant animals abortions may also occur. Suckling calves usually die due to acute myocarditis.
The animal becomes extremely weak and the milk production is decreased or stops giving milk.
The wounds on the hoof become bigger and sometimes the hooves may be sloughed off.
The characteristic lesions in the mouth and on feet are an indication for diagnosing the disease.
Laboratory confirmation by isolation of the virus is the sure diagnosis of the disease.
Serological tests can also be made for diagnosing the disease. Samples collected should be sent very carefully by preserving the samples in ice or frozen to preserve the virus. The samples also should be sent duly marked and taking care to prevent spillage and spread of the disease.
Animals will recover in 10 -15 days, there is no treatment available to cure the disease. In most of the developed countries if the disease is seen the entire herd are killed and buried.
Symptomatic treatment is only way to control the severity of the disease
Antibiotics can be given in secondary infections are seen
For the wounds in the mouth and on the tongue boric acid and glycerin can be applied to the wounds.
The feet are dressed by cleaning with pot. Permanganate lotion and a fly repellent dressing should be applied. If the wounds are big a dressing and bandage is helpful. Secondary infections should be controlled with suitable antibiotics.
Top priority should be given for preventing the spread of the disease. The animals’ should be removed from the herd kept separately and treated. The area should be quarantined and the movement of people should be restricted.
Vaccination should be done in all areas where the disease is endemic. Vaccination should be done with a polyvalent vaccine to coincide with the virus that caused the disease. The protection with vaccine is of short duration. Therefore vaccination should be repeated every 6 months. Crossbred animals should be vaccinated for every 3 months.