Tracing the source of the first case of PPR

The test results must be compared with epidemiological data

Official Letter 3603/CNTY-DT on provisional guidance for preventive measures against peste des petits ruminants (PPR) was sent by the Department of Animal Health to the Departments of Agriculture and Environment of provinces and cities on November 21.

In the document, Regional Animal Health Offices are assigned to coordinate with local specialized units to monitor, collect samples from all suspected cases, and organize outbreak investigations, including tracing infection sources for the first confirmed cases at the provincial level.

These are the two highest-priority tasks, directly linked to the capacity for early warning and prevention of disease spread.

The Department also emphasizes the need to control the disease from the onset of clinical signs. Local authorities are advised to conduct continuous surveillance in areas with concentrated goat and sheep farming, border zones, and locations where animals are traded and slaughtered.

Any goat or sheep showing high fever, ocular, nasal, or oral discharge, mucosal ulcers, or diarrhea must be sampled for testing. Samples must be stored at 2–8°C, transported within 24 hours, and tested using RT-PCR, real-time RT-PCR, ELISA, rapid tests, or genome sequencing.

“The positive result must be compared with epidemiological and clinical data to confirm the outbreak”, the document states.

If laboratory testing confirms the presence of the PPR virus, local authorities must isolate the entire affected herd and temporarily suspend the movement of goats and sheep within a minimum radius of 3 km around the related area. Local governments must declare the outbreak, cull infected animals or those showing symptoms, and urgently vaccinate all healthy animals in the affected commune and neighboring communes.

High-risk zones must be disinfected daily during the first week and three times a week over the following two weeks, with full progress reports sent to the Department of Animal Health.

High-risk areas may be vaccinated annually

PPR is a dangerous infectious disease present in more than 60 countries across Africa, the Middle East, and Asia, threatening much of the global goat and sheep population. Many countries continue to record new outbreaks, leading the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (OIE) to list it among priority diseases targeted for eradication by 2030.

As of October 2025, PPR has not been detected in Vietnam, but it remains on the list of dangerous animal diseases requiring surveillance. Cross-border livestock trade and small-scale farming practices create ongoing risks of disease introduction.

The infection rate through contact is 90–100 percent, with a fatality rate of 50–90 percent depending on viral virulence, husbandry conditions, and immune status. Goats are more susceptible than sheep. Buffalo and cattle may be infected but do not shed the virus. Humans are not affected.

The incubation period averages 4–5 days (ranging from 3–14 days). In the acute stage, animals develop high fever (40–41°C) lasting 3–5 days, accompanied by depression, anorexia, and dry nose. Later, ocular, nasal, and oral discharge appears, initially watery then becoming purulent, along with excessive drooling. Oral mucosal lesions may erode or become necrotic, and severe cases may show fibrin deposition on the tongue. Subsequent symptoms include diarrhea, coughing, labored breathing, weight loss, emaciation, rapid drop in body temperature, and death 5–10 days after onset. Bronchopneumonia, shown by coughing, may occur in late-stage disease. Pregnant animals may abort. Morbidity and mortality rates are higher in young animals than adults.

Some mild cases may recover after 10–15 days and gain lifelong immunity. Symptom severity, morbidity, and mortality depend on viral strain virulence, environmental conditions, and host immunity.

The virus spreads through secretions, feces, urine, and contaminated environments. Outbreaks tend to increase during the rainy season or dry periods, especially in animal trading areas.

To prevent and control PPR, OIE recommends two live attenuated vaccines, Nigeria/75/1 and Sungri/96, which provide at least three years of protection. Goats and sheep from three months old are eligible for subcutaneous vaccination.

Recognizing vaccination as the “shield” that protects livestock, especially against dangerous diseases like PPR, the Department of Animal Health recommends annual vaccination in high-risk regions and vaccination every 2–3 years in safe areas.

Biosecurity measures must be implemented uniformly, including isolating new animals for 21 days, disinfecting barns and equipment, managing waste, controlling personnel and vehicle access to farms, and regularly disinfecting markets and slaughter points.

The Department of Animal Health requests provincial Departments of Agriculture and Environment to compile a list of goat and sheep farms, trading points, and slaughterhouses; develop surveillance and vaccination plans; and guide facilities on traceability and response to positive cases.

Farm owners must report immediately when goats or sheep show unusual illness or death and must maintain complete monitoring records to support disease tracing.