Transmission of Lumpy Skin disease in animals (ਲੰਪੀ ਚਮੜੀ ਰੋਗ ਪਸ਼ੂਆਂ ਵਿੱਚ ਫੈਲਣ ਦਾ ਤਰੀਕਾ )

TRANSMISSION
The first case of LSD can often be traced to the legal or illegal transfer of cattle between farms,
regions or even countries. In fact, movements of cattle may allow the virus to jump over long distances. Short-distance leaps, equivalent to how far insects can fly (usually 50 km), are
occasioned by numerous local blood-feeding insect vectors feeding on cattle and changing
hosts frequently between feeds. No evidence exists of multiplication of the virus in vectors,
but it cannot be excluded. The principal vector is likely to vary between geographical regions
and ecosystems. The common stable fly , the Aedes aegypti mosquito,
and some African tick species of the Rhipicephalus and Amblyomma spp., have demonstrated
ability to spread the LSDV. Viral transmission from infected carcasses to naïve live animals via
insects is a possible risk, but has not been sufficiently studied Direct contact is considered ineffective as a source of infection, but may occur. Infected animals may be viraemic only for a few days, but in severe cases viraemia may last for up to two
weeks. Infected animals showing lesions in the skin and mucous membranes of the mouth
and nasal cavities excrete infectious LSDV in saliva, as well as in nasal and ocular discharges,
which may contaminate shared feeding and drinking sites. To date, infectious LSDV has been
detected in saliva and nasal discharge for up to 18 days postinfection. More research is needed
to investigate how long the infectious virus is excreted in such discharge.
Infectious LSDV remains well-protected inside crusts, particularly when these drop off
from the skin lesions. Although no experimental data are available, it is likely that the
natural or farm environments remain contaminated for a long time without thorough
cleaning and disinfection. Field experience shows that when naïve cattle are introduced to
LSDV-infected holdings after stamping out, they become infected within a week or two –
indicating that the virus persists either in vectors, the environment, or both.
The virus persists in the semen of infected bulls so that natural mating or artificial
insemination may be a source of infection for females. Infected pregnant cows are known
to deliver calves with skin lesions. The virus may be transmitted to suckling calves through
infected milk, or from skin lesions in the teats
PREVENTION OF LUMPY SKIN DISEASE
• The best protection comes from prophylactic vaccination of the entire cattle population, carried out well in advance in at-risk areas.
• Movements of cattle inside the country and across borders should be strictly controlled or
totally banned. Authorized cattle movements should be accompanied by a veterinary certificate including all data concerning the animals’ origins, and animal health guarantees.
• In affected villages, cattle herds should be kept separate from other herds by avoiding communal grazing, if possible without animal welfare issues. However, in some
cases the whole village forms a single epidemiological unit and then the feasibility of
separation has to be evaluated on a case-by-case basis.
• Movements of vaccinated animals can be allowed within a restricted zone within a
country after it has been established that full immunity has been provided by a vaccine with proven efficacy (28 days after vaccination).
• Cattle should be treated regularly with insect repellents to minimize the risk of vector
transmission of the disease. This measure cannot fully prevent transmission but may
reduce the risk.
INSECT CONTROL ON ANIMALS AND IN THE ENVIRONMENT
Efficient insect control on cattle or in holdings may reduce the rate of mechanical transmission, but cannot totally prevent it, particularly where cattle are free-roaming or kept in
fenced pastures. Anti-mosquito nets can be considered in cases when cattle are permanently kept indoors. The application of spot-on repellents can protect cattle from insects
and ticks for short periods.
When insecticides are used, withdrawal times for milk and meat need to be considered.
Large-scale use of insecticides in the environment is not recommended as it may be harmful
to the ecological balance, and to other useful insects such as honeybees. Moreover, the risk
to the environment is not fully understood.
Limiting vector breeding sites such as standing water sources, slurry and manure, and
improving drainage in holdings are sustainable, affordable and environmentally friendly
ways of reducing the number of vectors on and around cattle.