But the virus causing the disease persists in almost all places
The outbreak of foot-and-mouth disease (FMD) which led to the death of more than 200 head of cattle in Kerala has been brought under control, though the virus causing the disease persists in most parts of the State, says the Department of Animal Husbandry. Officials maintain that the disease has crossed its peak and is on the decline, but farmers are concerned.
Most of the 200 dead animals were calves which succumb easily to the deadly virus. Scientists from the Southern Regional Diagnostic Laboratory in Bangalore and the All India Coordinated Research Project on FMD had visited Kerala to support the investigations carried out by the Chief Disease Investigation Laboratory here.
Animal Husbandry Director V.Brahmanandan told The Hindu that the latest outbreak of FMD had affected not only neighbouring States like Karnataka and Tamil Nadu, but also large parts of India and Bhutan. He said the timely control measures adopted by the department in Kerala had helped to keep the mortality rate down.
A 10-day ban was imposed on the entry of cattle from neighbouring States following a preliminary assessment that FMD had spread to Kerala from diseased animals imported for meat. The government also initiated an extensive vaccination drive followed by disinfection and administration of antibiotics for outbreak management. The ‘O’ strain of the virus, the most virulent type, has been found to be responsible for the recent outbreak.
FMD symptoms include high temperature, shivering, and salivation. As the disease progresses, lesions appear on the foot and mouth and death is caused by loss of functional lung tissue.
Dr. Brahmanandan said timely reporting was crucial in controlling the viral disease. While calves easily give in to the heart lesions caused by the virus, adult cattle often die of secondary infections. Interestingly, the disease has not been reported in any of the government-owned farms in the State.
Spread of the disease
FMD usually spreads either through feed or contact with the milker or from animals carrying the disease. Pigs are amplifying hosts for the virus. Wild pigs ravaging crops near human settlements can pass on the virus to cattle. Officials say that cattle bought from neighbouring States or people who milk cows on both sides of the State border could have transmitted the disease.
The department estimates that the current outbreak of FMD is past its peak stage. “Post infection, the cattle population in an area develops immunity. Our experience shows that the field virus is stronger than the vaccine virus,” Dr.Brahmanandan said.
“The prolonged rains in Kerala could have been responsible for the extended phase of the disease since the virus thrives in wet conditions,” he said.
The department is carrying on a mop-up operation to ensure that the remaining cattle are also vaccinated.
“According to the latest assessment, FMD is well within control though the mild outbreaks across the State show that the virus is persisting,” Dr. Brahmanandan said.