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.

Management control and prevention

The control programme adopted has been in two phases.

• In 1999 there was a mass culling of pigs in infected areas and severe restrictions on movement of pigs.
• This has been successful in preventing disease spreading to Singapore where many pigs from Malaysia were slaughtered.
• The second phase is the identification of carrier herds and their depopulation.

Further reading

For further more indepth information on Nipah disease, read the following articles below. News on the most recent outbreaks in Malyasia can be found in the latest news archives:

Nipah Virus, Malaysia - Emerging Disease Notice Excellent article from CEI (Centre for Emerging issues) discussing the disease, its background and transmission etc. - May 1999

Nipah disease in Malaysia A thorough article from O.I.E covering all aspects of the disease. - May 1999

Nipah Virus Encephalitis A good article from National Neuroscience Institute of Singapore looking at the human aspects of the disease. - November 1999

Several articles from Pighealth.com A number of articles on Nipah and Hendra virus.

The Nipah Virus Outbreak - A Reminder P A Tambyah - Singapore Medical Journal 1999; Vol 40(05):

Lesson to be Learnt from the Nipah Virus Outbreak in Singapore A E Ling - Singapore Medical Journal 1999; Vol 40(05):