PESTE
DES PETITS RUMINANTS (PPR)
PPR is a highly contagious, widespread, virulent and
devastating small ruminant's (Sheep & Goats) disease caused by a morbillivirus of family Paramyxoviridae, closely related to
Rinderpest Virus (RP).
The genome of PPRV is -ve single stranded RNA. The disease
has also been reported in camels, cattle and wildlife (buffaloes and gazelles).
PPR occurs in most African countries situated in a wide belt between the Sahara and equator, the Middle East (Arabian Peninsula, Israel, Syria and Jordon) and
the Indian subcontinent. It still causes serious economic losses and remains a
major constraint on the development of small ruminant farms in these countries.
The disease is OIE notifiable in all the regions where it is endemic.
- Seasonality: more common in the rainy season or dry cold season
- Mobility: Livestock mobility favors contact between infected and susceptible herds.
- The presence of naïve populations within an infected region
- Malnutrition, parasitism and bacterial infections which aggravate clinical disease
- Close contact in large groups of herding animals enables rapid spread of the virus
- Unregulated livestock trade and porous borders between neighboring countries
PPRV is
transmitted by direct contact with secretions and excretions of infected
animals. It is highly contagious and all discharges can carry virus.
Substantial quantities of virus are found in ocular nasal or oral secretions of
sick goats and in the faeces late in disease.
The incubation period is about 4 days. The disease
is more severe in young animals. Affected Goats exhibit fever, dry muzzle, crusting
around the mouth and nose, and also open- mouthed breathing and a serous nasal
discharge which becomes mucopurulent. Erosions/ulcers on the mucous membrane of
the mouth are accompanied by marked salivation and reluctance to eat. Conjunctivitis
with ocular discharge is a feature of the disease. Profuse diarrhea, which
results in dehydration, develops within days of infection. Pregnant animals may
abort. Pulmonary infections caused by
Pasteurella species are common in the later stages of the disease. Mortality
rates in severe outbreaks often exceed 70 % and affected goats may die within
10 days of exposure to the virus.
Definitive diagnosis of PPRV infection relies on
laboratory techniques such as virus isolation, demonstration of PPRV antigen,
viral nucleic acid and specific antibodies. PPRV antibodies can be
differentiated from RP antibodies by competitive ELISA and serum neutralization
test. c-ELISA is rapid, sensitive and specific and most commonly used technique.
The disease must be differentially diagnosed from Foot
and Mouth Disease, Bluetongue, contagious ecthyma, Pasteurellosis and Contagious
Caprine Pleuro-pneumonia.
Control of
PPR outbreaks relies on movement control combined with the use of vaccine.
Proper disposal of carcass and contact fomites, decontamination and restriction
on importation of sheep and goats from affected areas.
Dr.
Moses Bwana
Post-grad at the University of Nairobi
Veterinary Applied Microbiology (Virology Option)
Cell: +254729246187
Email: bwanamoses@gmail.com
