Download Peste des petits ruminants

Peste des petits ruminants
Author: Prof Moritz van Vuuren
Adapted from: ROSSITER, P.B., 2004. Peste des Petits Ruminants. In: COETZER, J.A.W. & & TUSTIN, R.C. (eds). Infectious
Diseases of Livestock Cape Town: Oxford University Press Southern Africa.
Licensed under a Creative Commons Attribution license.
Synonyms
clinical disease caused by rinderpest virus in small
Goat plague, Kata (a vernacular west-African name),
ruminants was a relatively rare event, and will likely not
pseudorinderpest,
be seen again as a result of the eradication of
and
stomatitis-pneumo-enteritis
complex.
rinderpest.
Introduction
There is an incubation period of 3-4 days during which
Peste des petits ruminants (PPR) is a disease of goats,
the virus replicates in the draining lymph nodes of the
sheep and closely related wild members of the family
oro-pharynx before spreading via the blood and lymph
Bovidae, and is clinically and pathologically similar to
to other tissues and organs. The characteristic signs
the now extinct rinderpest. In the areas where it occurs
begin with fever and a serous nasal discharge that
it is the most economically important virus disease that
becomes mucopurulent. Other signs include a profuse
affects small ruminants. The chronological sequence of
catarrhal conjunctivitis with matted eyelids, necrotic
new reports of PPR points to the fact that the virus has
stomatitis, gastroenteritis, and bronchopneumonia.
spread steadily eastwards from its origin in West Africa,
and more recently southwards on the continent of
Africa.
Salient features of PPR
Peste des petits ruminants virus causes an acute
febrile illness in small ruminant species, mostly sheep
and goats, with the highest pathogenicity in goats. It is
an economically important disease and can cause
Hyperaemia and congestion of the conjunctiva
mortality rates of 50-80% in naïve populations. In areas
where the disease is endemic, the most severely
affected animals are those from 4 to 24 months-of-age.
Antelope and other small wild ruminants species in
captivity can also be severely affected. The virus is
classified in the Morbillivirus genus of the
Paramyxoviridae family.
The virus is antigenically very similar to rinderpest virus
and the clinical signs are similar to rinderpest in cattle,
which made differential diagnosis difficult. However,
Severe purulent nasal exudate
Where does PPR occur?
The disease occurs in Africa, the Middle East and the
The renewed spread of PPR in Africa and the Middle
Indian subcontinent. In Africa it is known to be present
East has not only to do with biological factors, but is
in a broad belt of sub-Saharan Africa between the
also considered to be influenced by deteriorating
Equator and Sahara desert including the Horn of
standards in national veterinary services in many
Africa. During the late 1980s, the disease spread to the
countries. Changes in government priorities have lead
Arabian Peninsula, throughout most of the Middle-
to decreased funding and a restructuring which has
Eastern countries, and eastwards. Outbreaks of PPR
disrupted national veterinary services.
are now known to be common in India, Nepal,
Bangladesh, Pakistan, Afghanistan, and since July
2007 in Tibet (China). According to sero-surveys, PPR
virus had already been circulating in Kenya and
Uganda during the 1980's but has been officially
declared to the OIE as endemic in Kenya since 16 May
2007, and in Uganda since 10 Aug 2007. The disease
is now (2013) recognized as also being present in the
Democratic Republic of Congo and northern Angola.
Prevention and control
The control of PPR is dependent on zoosanitary
measures and vaccination. The former may variously
include quarantine of infected premises, villages or
areas; cleaning and disinfection of infected premises;
movement control in general, including transhumance;
and stamping out in the event of new introductions.
Eradication of PPR in the endemic areas is not
currently viewed as feasible as a result of the risk of reinfection from neighbouring regions, and would require
serious regional coordination and collaboration.
Vaccination represents the most important procedure
for the control of PPR. As a result of the close antigenic
relationships, attenuated rinderpest vaccines have
been used to protect sheep and goats against PPR.
Today attenuated PPR vaccines are available and are
manufactured and marketed in African and Asia.
Global distribution of PPR prior to its southern
Recombinant poxvirus vaccine and chimeric rinderpest
migration into Tanzania, DRC and Angola between
virus vaccine were developed during the first decade of
2007 and 2012
this century, but their wide scale use has not yet
materialized.
What triggers an outbreak of PPR?
Transmission of PPR requires close contact and the
movement of live animals are the main means of
spread. The virus is present in ocular, nasal, and oral
secretions as well as faeces. Most infections occur
through inhalation of aerosols from sneezing and
coughing animals. Animals may be infectious during
the incubation period. There is no known carrier state.
There is controversy over whether fomites can play a
role in transmission of PPR virus as it is a labile virus
sensitive to environmental influences.