This is a totally new disease that first became evident in September 1998 in Malaysia. In March 1999 a previously unknown virus was isolated from an adult male who having had contact with pigs died. The virus was identified as a previously unknown paramyxovirus and the disease was called Nipah Disease from the village in Malaysia where it was first identified.
The virus causes illness and death in both humans and pigs.
Symptoms
Humans
Symptoms may be mild or severe and include:
- Fever, headaches, encephalitis.
- Drowsiness, confusion leading to coma.
- Respiratory failure.
- High mortality up to 40% reported.
- A few people have shown no symptoms.
- The incubation period is from 7 to 21 days.
In 1999 there were over 300 cases and 100 deaths.
All Pigs
- Morbidity is usually high but mortality is low.
- Rapid laboured breathing.
- Very harsh explosive cough.
- In sows disease may be more pronounced with severe breathing difficulties.
- Convulsions, death.
- Pneumonia.
- Mucopurulent discharges from the nose.
At post mortem the predominant signs are consolidation of the lungs.
Causes / Contributing factors
- Movement of pigs.
- Direct pig to pig contact either by mouth, by the respiratory route or aerosol from urinary excretions.
Diagnosis
This is by serological tests, virus isolation and identification. In infected farms sows show high levels of antibodies and in infected areas antibodies have been widespread in dogs but not in rats.