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.
In non-endemic areas such as Europe, the first introduction to a new area is often
via pigs which get infected by ingestion of infected meat scraps. Spread from these
pigs to cattle is via movement of people, abattoir waste or animals. Further spread
between cattle is more likely to be by airborne means.
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, viremia 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 but Buffaloes, 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.
Regular outbreaks once in six years are noticed in India, which affects the whole
population and then subsides. The immunity lasts for 1 to 4 years after natural
infection in cattle.
Clinical Findings :
Incubation period in cattle will be 3 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 eventhough 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 not possible 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
DEPARTMENT OF ANIMAL HUSBANDRY, DAIRYING AND FISHERIES
In order to prevent, control and contain the Foot and Mouth Disease in the country,
the Department has initiated Foot and Mouth Disease Control Programme (FMD-CP) since
10th Five Year Plan Period in 54 districts which was extended to 221 districts in
the 11th Five Year Plan Period.
During 12th Plan Period, it is envisaged to cover all the remaining States in a
phased manner subject to overall availability of funds and vaccine. Accordingly,
the scope of the programme has already been expanded during 12th Plan Period up
till now to cover remaining districts of Uttar Pradesh and all the districts of
Rajasthan & Bihar.
Therefore, as of now, FMD Control Programme is being implemented in 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.
Till such time, all the districts in the country are brought under FMD-CP, need-based
FMD vaccination are carried out under a centrally sponsored scheme of the Department
i.e. ‘Assistance to States for Control of Animal Diseases (ASCAD)’.
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.
Courtesy :
ICAR-Directorate on Foot and mouth Disease – Annual report 2015-16
