If Nipah Symptoms Found Don’t Stigmatize but Isolate Patient – DHO Dr Ramakrishna
Mangaluru: The Nipah Virus (NiV) is an emerging infectious disease which first appeared in domestic pigs in Malaysia and Singapore in 1998 and 1999. There is evidence of Nipah infection among several species of domestic animals including dogs, cats, goats and horses. Sheep may also be affected. “However, since the initial outbreak, it has primarily affected humans in different parts of the world. The disease causes respiratory and occasionally nervous signs in pigs. It has devastating zoonotic potential. In Mangaluru, we have received two suspicious cases of Nipah. We have sent the samples to Manipal for testing and are waiting for the reports”, said District Health Officer Dr Ramakrishna in a press meet held at the DHO’s office here on May 22.
Dr Ramakrishna explained more about the virus, methods of transmission, etc. “The organism which causes Nipah virus encephalitis is an RNA virus of the family Paramyxoviridae, genus, Henipavirus and is closely related to Hendra Virus. Hendra Virus, formerly known as equine morbillivirus pneumonia or acute equine respiratory syndrome, is an acute, viral respiratory infection of horses and humans that have been reported in Australia,” he said.
Nipah virus infection, also known as Nipah Virus Encephalitis, was first isolated and described in 1999. The name, Nipah is derived from the village in Malaysia where the person from whom the virus was first isolated succumbed to the disease.
Nipah virus is a disease listed in the World Organization for Animal Health (OIE) Terrestrial Animal Health Code and must be reported to the OIE. Hendra virus is not yet an OIE listed reportable disease.
How is Nipah Transmitted and Spread?
Fruit bats, also known as “Flying Foxes”, of the genus Pteropus are natural reservoir hosts of the Nipah and Hendra viruses. The virus is present in bat urine and potentially, bat faeces, saliva and birthing fluids. Perhaps as a result of deforestation programmes, the Malaysian pig farms where the disease first originated had fruits trees which attracted the bats from the tropical forest, thus exposing domestic pigs to bat urine and faces. It is thought that these excretions and secretions initiated the infection in pigs which was then followed by a rapid spread through intensively reared pigs. Furthermore, transmission between farms may be due to fomites or carrying the virus on clothing, equipment, boots, vehicles, etc.
What is the public health risk associated with this disease?
Nipah Virus is a Zoonotic disease. Transmission to humans in Malaysia and Singapore has almost always been from direct, contact with the excretions or secretions of infected pigs. Reports from outbreaks in Bangladesh suggest transmission from bats without an intermediate host by drinking raw palm sap contaminated with bat excrement or climbing trees coated in bat excrement.
Typically the human infection presents as an encephalitic syndrome marked by fever, headache, drowsiness, disorientation, mental confusion, coma, and potentially death. During the outbreak in Malaysia, up to 50% of clinically apparent human cases died. There is no specific treatment for Nipah Virus. Supportive care is the general treatment for this disease.
What are the clinical Signs of Nipah Virus?
Nipah Virus in pigs affects the respiratory and nervous systems. It is known as porcine respiratory and neurologic syndrome, porcine respiratory and encephalitis syndrome (PRES) and barking pig syndrome (BPS). It is a highly contagious disease in pigs, however, the clinical signs vary depending on the age and the individual animal’s response to the virus. In general, mortality is low except in piglets. However, morbidity is high in all age groups.
Most pigs develop a febrile respiratory disease with a severe cough and difficulty in breathing. While the respiratory sings predominate, encephalitis has been described, particularly in sows and boars, with nervous signs including twitching, trembling, muscle fasciculation, spasms, muscle weakness, convulsions and death. Some animals, however, remain asymptomatic. Natural infection of dogs with NiV causes a distemper-like syndrome with a high mortality rate.
How is the disease diagnosed?
The disease is difficult to diagnose based on clinical signs alone, however, confirmation can be made through prescribed laboratory tests.