In 2001 Britain experienced a devastating outbreak which also spread to Ireland and Netherlands before it was finally controlled. The cause
here was found to be illegal import of infected meat products to UK. The disease spread was due to movement of animals which showed no prominent clinical signs.
The last outbreak in USA was in 1929, Canada in 1951-52 and in Mexico in 1946-1954.Japan suffered a serious outbreak of FMD in 2010. In 2015 South Korea reported
FMD outbreaks in swine farms resulting in the destruction of 2774 pigs. Usually the disease occurs as an outbreak which spread very rapidly from herd to herd before it is controlled.
There are Seven major serotypes viz., A, O, C, South African Territories (SAT)1, SAT2, SAT3 and Asia1 for FMD Virus. Among these, O and A are most common in all endemic countries.
There is no cross immunity between serotypes which means one type does not confer protection against others. This is the major constraint for vaccination programmes,
further the antigenecity also varies dramatically between developing serotypes.
The transmission of FMD will be by a variety of methods between herds, countries and continents but spread from one animal to another is by inhalation or by ingestion. In endemic areas,
the most important method of spread is by direct contact between animals moving across state and national boundaries as trade or nomadic cattle.
The virus can persist in aerosol form for long periods in temperate or subtropical climates but not in hot and dry climates. The speed and direction of the wind are important factors
in determining the rate of airborne spread. Humidity is also important. In the most favourable circumstances, virus can be spread to a distance of 250 Km by wind.
Pigs are the most potent excretors of airborne virus and cattle the most susceptible to airborne infections.
In cattle, the virus first infects and multiplies rapidly in pharynx then a few days later, viraemia occurs and the virus appears in milk and saliva for
upto 24 hours, later the vesicle formation can be noticed. All the secretions and excretions can be infective before the animal is clinically ill and also
after the symptoms disappear. The virus will be at highest concentration in the vesicular fluid. Some of the animals are believed to remain as carriers and
this issue is gaining importance in the epidemiology of the disease. Human being can act as vehicle of transmission of the disease.
The virus persists in the nasopharynx and may be excreted in erratically low level for upto 2 years. The mammary tissue also is a site of persistence for 3-7 weeks.
The spread of the disease from herd to herd will be either directly by the movement of animals or indirectly by transportation of virus on inanimate objects,
especially uncooked and unprocessed meat products and other animal products like milk.
The Disease is most important in cattle and pigs. Goats, sheep and buffaloes in India are also affected. The Disease in Buffalo population is usually
mild but the infection rate is high and persistent.
The virus is resistant to common disinfectants, it can persist for 1 year in infected premises, 10 to 12 weeks on clothing and feed,
and upto a month on hair, but 1-2% Formalin, and 4% Sodium carbonate can destroy the virus within minutes.
Clinical Findings :
Incubation period in cattle can range from1-14 days however, incubation period in cattle is usually 2 to 6 days; symptoms start with
reduced milk yield, followed by high temperature (104O F to 106O F), anorexia and acute painful stomatitis.
The temperature slowly subsides and Profuse salivation, with ropy saliva with vesicle or bullae on buccal mucosa, tongue and dental pad.
The vesicles rupture in 24 hours leaving raw surfaces which will be painful and heals about in 1 week. Simultaneously vesicles appear in the clefts
of hooves or on the coronet region causing lameness.
A Chronic syndrome of dyspnoea, anemia, over growth of hair and lack of heat tolerance will be noticed as sequel to FMD in cattle which might be due to endocrine damage.
Economic Importance of FMD
FMD is the most feared Disease in the Developed countries only may be second to BSE. This is because of the high morbidity even though the mortality and case fatality rates are low.
As per the OIE and FAO, the disease is a major threat to food security of the world, and particularly the countries having the disease are more prone to food insecurity. Further,
FMD free status is an indicator of development, and all developed countries are free from it.
The 2001 outbreak of UK alone resulted in losses approximating US $ 12Billionwith about 10 million livestock deaths in spite of the eradication of the disease within 7 months.
At present, in India the disease occurrence, severity of the clinical disease and number of outbreaks have progressively and substantially declined in the control zones
as a result of several rounds of vaccinations with an oil adjuvant trivalent inactivated vaccine.
In India, the direct loss is over and above 20,000 crore/annum that is due to significant drop in milk yield (up to 80%), loss in drought power,
reduction in meat and wool production, abortion in pregnant animals and mortality in calves. Indirect loss could be much more and due to trade barrier
imposed by the countries free from FMD, and massive expenditure by Government on FMD control and cost of treatment lead to further economic loss. However,
the state-wise losses due to FMD have not been estimated.
FMD Control :
FMD is being controlled by Eradication or Vaccination or by combination of both, but eradication is practically a difficult proposition
in endemic countries like India as we have wild life reservoirs.
In endemic countries, Vaccination is the only measure to control the disease. A Single vaccine shot can protect the animal only
for about 6 to 8 months. Young animals with maternally derived antibodies do not respond to vaccine.
In endemic countries, Vaccination is the only measure to control the disease. A Single vaccine shot can protect the animal
only for about 6 to 8 months. Young animals with maternally derived antibodies do not respond to vaccine.
GOVERNMENT OF INDIA, MINISTRY OF AGRICULTURE AND FARMERS WELFARE
DEPARTMENT OF ANIMAL HUSBANDRY, DAIRYING AND FISHERIES
In order to prevent, control and contain the Foot and Mouth disease and to prevent economic losses and develop herd
immunity in cloven footed animals, the Department has initiated Foot and Mouth Disease Control Programme in the country.
The Foot and Mouth Disease Control Programme (FMD-CP) had been initiated since 10th Five Year Plan in 54 districts which was
extended to 221 districts in the 11th Five Year Plan period. During the 12th Plan period the scope of the programme have been
expanded to cover 351 districts of Andhra Pradesh, Telangana, Maharashtra, Kerala, Tamil Nadu, Gujarat, Punjab, Haryana, Uttar Pradesh,
Karnataka, Goa, Rajasthan, Bihar, Puducherry, Delhi, Andaman & Nicobar, Dadra & Nagar Haveli, Daman & Diu and Lakshadweep. Presently,
all the districts in the country are brought under the coverage of the Control Programme covering 29 States and 7 Union Territories.
The major activities of the intensive programme component is to vaccinate all the eligible cattle and buffaloes at six monthly interval,
Publicity and Mass Awareness Campaign, including orientation of the State functionaries for implementation of the scheme, identification
of the target animals, Serosurveillance/monitoring of animal population on random basis, mass vaccination, procurement of cold cabinets
and FMD vaccine, assessment of the randomly collected samples of vaccines for their quality, virus typing in case of outbreaks and
recording/regulation of animal movement from unvaccinated areas through temporary quarantine/ check-posts.
To assess the effectiveness of the vaccination programme, serum samples of 10 cattle and 10 buffalo (at random) before vaccination and
21-30 days post vaccination from 10 villages at random from each district for each round of vaccination should be collected and screened
for level of serotype specific neutralizing antibodies. A total of 400 serum samples per district per round of vaccination will be continued
to be collected at random and tested.
In order to have early warning system in place, State Government is required to undertake surveillance of FMD. In the event of any outbreak,
it should be reported immediately and the state should take action to control and contain the disease as per the provisions of the Prevention
and Control of Infectious and Contagious Diseases in Animals Act, 2009:
• Each and every outbreak should be investigated to know the epidemiology of the disease with forward and backward linkage.
• Isolation and containment of sick animals and their treatment.
• Ring vaccination (5-10 Km) radius around the affected village/area to cover all the susceptible animals including sheep, goats, pigs etc. to prevent virus transmission
• Restriction/control of movement of infected animals to prevent the spread of the infection.
• Disinfection and implementation of bio-security measures
• Adequate Public awareness campaign in outbreak areas.
Based on the effective vaccination under the Foot and Mouth Control Programme, the country has proposed “FMD Free Zones with vaccination”
in four states of Andhra Pradesh, Telangana, Maharashtra, and Punjab following the guidelines of World Organization of Animal Health (OIE).
It is expected that with the implementation of a planned control programme covering the whole country in a phased manner under FMD-CP,
the vaccination will be gradually stopped and the disease brought controlled in entire country by the year 2025.
