Peste des petit ruminants

Peste des Petits Ruminants (PPR) is a notifiable and serious viral disease of small ruminants, such as goats and sheep. Infection occurs through direct contact or intensive indirect contact between sick and susceptible animals. Wageningen Bioveterinary Research (WBVR) conducts research into this disease.

Notifiable means that suspicions of a peste des petits ruminants infection must be reported to the NVWA. PPR is a “Category A” disease (Animal Health Law). The disease is caused by the peste des petits ruminants virus (PPRV, Family of Paramyxoviridae, genus Morbillivirus).

There are four subtypes or lineages of the virus. Infected animals almost always get sick (about 90%) and 50% to 80% of infected animals can die. The virulence (pathogenic potential) varies between virus variants and differs per animal species and breed. After the worldwide eradication of the related rinderpest virus, international organizations have expressed the ambition to eradicate peste des petits ruminants worldwide.

Humans are not susceptible to peste des petit ruminants.

PPR has never been reported in the Netherlands. The Netherlands is therefore historically free of peste des petits ruminants.

Clinical signs peste des petits ruminants

Clinical signs appear after an incubation period of 2 to 8 days. Infection with peste des petit ruminants virus almost always leads to disease. In addition to sheep and goats, many other ruminants and pigs can also be infected. Cattle and pigs do not get sick (subclinical infection).

Symptoms are:

Spread of peste des petits ruminants

Peste des petit ruminants occurs in Africa, the Arabian Peninsula, the Middle East and India. The four different subtypes (lineages) have different but overlapping distribution areas. Remarkably, lineage 4 has recently spread from India westwards as far as Morocco. Europe is free of this disease, but based on serological monitoring, peste des petit ruminants was recently reported in an area in Bulgaria bordering Turkey.

Body fluids

Infection occurs through direct contact or intensive indirect contact between sick and susceptible animals. PPRV is excreted in all body fluids, mainly from the nose and eyes and in manure, but presumably also in semen and milk. PPRV is related to rinderpest virus and the measles virus that can infect humans. Like measles, PPR is a highly contagious disease. Humans are not susceptible to peste des petit ruminants.

Cattle and pigs can also be infected with PPRV, but in these animal species the disease often goes undetected (subclinical) and probably produces too little virus for further spread (dead-end hosts). Humans cannot be infected with the PPRV.

Diagnostics peste des petits ruminants

Peste des petit ruminants is a notifiable animal disease. Wageningen Bioveterinary Research (WBVR) is the national reference laboratory for PPR and has ISO-certified tests to diagnose suspicions of PPR.

Serological test

Antibodies against peste des petit ruminants virus (PPRV) after infection or vaccination can be detected with the ELISA or the serum neutralization test (SNT). The ELISA is the first choice for detecting antibodies. The SNT can confirm positive ELISA results, although the SNT is less sensitive. Clotted blood (serum blood) is used in these serological tests.

PCR test

The virus can be detected by the PCR test for PPRV. The test uses an alternative positive control. Whole blood (EDTA blood), spleen, lymph nodes and nasal and eye discharges are suitable for detecting virus. Samples of blood or organs must be transported on ice (not frozen).

Vaccine peste des petits ruminants

Live attenuated (LAV; live-attenuated vaccine) peste des petit ruminants virus is widely used outside Europe to reduce the effects of PPR outbreaks. The vaccine protects against all four subtypes. LAV for PPR is not registered in Europe and thus not available in the Netherlands.

Prevention and control of peste des petits ruminants

To prevent is better than to cure, but preventive vaccination for peste des petit ruminants is not used in Europe. To prevent outbreaks in Europe, animals are banned from infected regions or checked extensively before they are allowed.

In an outbreak of peste des petit ruminants, vaccination is installed to prevent further spread of disease. In addition, transport bans will be installed and protection and surveillance zones will be established. In 2018, after serologically positive animals were found in Bulgaria bordering Turkey, the European Commission authorized vaccination with an unregistered PPR vaccine. No further spread of disease was reported thereafter.