# 758
Most of my readers are likely unfamiliar with the Nipah virus, which has recently erupted in Bangladesh. While restricted to remote places like Malaysia and Bangladesh thus far, health officials are watching it carefully, cognizant of the fact that it could spread to other parts of the world.
This article (Hat Tip Snowy Owl on Flutrackers) from the Brisbane Times.
Health authorities on alert for killer Asian virus
Shannon Molloy | May 13, 2007 - 12:00AM\\
The Nipah virus has no cure, spreads rapidly, and kills most infected within 72 hours. Cases are isolated to parts of Bangladesh and West Bengal so why is Queensland Health on alert?
The disease was first discovered in Malaysia in 1999, and since has only been known to strike in parts of Bangladesh and Bengal.
Recently it has appeared in Nadia a district of the state of West Bengal in the north east of India killing three people and possibly infecting at least 30 people.
Queensland Health alerted hospitals about the outbreak in Asia and the symptoms of infection, but the chances of an outbreak here are slim.
Queensland Health's director of the Communicable Diseases Unit Dr Christine Selvey said she was aware of the outbreak in Asia.
"Although the risk of an infected person travelling to Australia was obviously very small, Queensland Health nonetheless took the precautionary measure of advising public hospitals of the outbreak and symptoms of Nipah virus,'' Dr Selvey said.
Evidence suggests the disease can be spread human-to-human, as most of the patients during an outbreak in Siliguri, West Bengal were hospital employees or visitors.
In Siliguri in 2001 the disease killed 49 people six years ago. When it was discovered in Malaysia, 105 of the 265 infected died. In Bangladesh, 18 of the 30 infected were killed.
In most outbreaks the mortality rate was between 60 and 90 per cent.
An Indian newspaper reported that one victim had become ill after returning from a business trip to a neighbouring country.
Apart from human-to-human infection, the other commonly suspected forms of transmission includes bats, pigs and other animals.
The wife of one of the dead told the same newspaper that bats were common in her area. Transmission is thought to require close contact with infected tissues or body fluids.
Domesticated dogs and cats are although thought to be possible carriers. Pigs bitten by bats can also pass the disease on to humans.
Nadia's chief health officer has asked locals to trim fruit trees to discourage bats, and to stop eating pork.
There is no cure for the disease, but authorities are using an anti-viral drug to help ease symptoms.
They include a high temperature, muscle pain, nausea and convulsions. In 60 per cent of cases, patients can lapse into a coma.
A conclusive cause for the emergence of the disease has not been discovered, but there are many theories.
One suggests that outbreaks occur with increase contact with bats, either by humans moving into bats' territory, or movement of bats due to changes in food distribution and loss of habitat.
There is evidence of habitat loss for flying foxes in South Asia and Australia, particularly along the eastern coast, according to the US Centre for Disease Control.
What? Avian Flu isn't enough to worry about? Now we have to concern ourselves with the Nipah Virus?
While the H5N1 avian flu concerns us most right now, it isn't the only pathogenic player out there. Being an influenza, H5N1 has the greatest potential to spread globally, and so it remains atop our list.
The Nipah virus was discovered in 1999, although it most certainly has been around a long time. As man encroaches on the habitat of wild animals to build homes, and farms, and to harvest timber, we expose ourselves to pathogens we'd normally never have contact with.
Such appears to be the case with the Nipah virus.
Fruit bats appear to be the natural reservoir of the virus, and it has been suggested that as they fly over pig pens erected in the bat's habitat they drop infected fruit or saliva and contaminate the pigs. From there, the virus has a route to humans.
As with any virus, we worry that the more human or pig infections that occur, the better the virus will adapt to those hosts.
The mode of transmission is uncertain. The fact that visitors to hospitals have acquired it is worrisome. There was an outbreak in Malaysia in 1998 where 265 people were infected, and 105 died. Most of these victims had direct occupational exposure to pigs.
Here are a few pithy excerpts from the WHO fact sheet on Nipah.
Nipah virus
- Nipah virus is a newly recognized zoonotic virus. The virus was 'discovered' in 1999. It has caused disease in animals and in humans, through contact with infectious animals. The virus is named after the location where it was first detected in Malaysia.
- Nipah is closely related to another newly recognized zoonotic virus (1994), called Hendra virus, named after the town where it first appeared in Australia.
- It is currently believed that certain species of fruit bats are the natural hosts of both Nipah and Hendra viruses. They are distributed across an area encompassing northern, eastern and south-eastern areas of Australia, Indonesia, Malaysia, the Philippines and some of the Pacific Islands.
- The bats appear to be susceptible to infection with these viruses, but do not themselves become ill. It is not known how the virus is transmitted from bats to animals.
- The mode of transmission from animal to animal, and from animal to human is uncertain, but appears to require close contact with contaminated tissue or body fluids from infected animals.
- Nipah antibodies have been detected in pigs, other domestic and wild animals. The role of species other than pigs in transmitting infection to other animals has not yet been determined.
- It is unlikely that Nipah virus is easily transmitted to man, although previous outbreak reports suggest that Nipah virus is transmitted from animals to humans more readily than Hendra virus.
- Pigs were the apparent source of infection among most human cases in the Malaysian outbreak of Nipah, but other sources, such as infected dogs and cats, cannot be excluded. Human-to-human transmission of Nipah virus has not been reported.
- The incubation period is between 4 and 18 days. In many cases the infection is mild or inapparent (sub-clinical). In symptomatic cases, the onset is usually with "influenza-like" symptoms, with high fever and muscle pains (myalgia).
- The disease may progress to inflammation of the brain (encephalitis) with drowsiness, disorientation, convulsions and coma. Fifty percent of clinically apparent cases die.
- No drug therapies have yet been proven to be effective in treating Nipah infection. Treatment relies on providing intensive supportive care. There is some evidence that early treatment with the antiviral drug, ribavirin, can reduce both the duration of feverish illness and the severity of disease.
None of this is to suggest that the Nipah virus has pandemic potential, at least not in its current form. Outbreaks have been limited, and that is a positive sign.
But every year we find new and exotic emerging infectious diseases coming from the wild, and their potential for havoc cannot be ignored. Diseases that easily infect pigs often find a way to adapt well to humans.
We are seeing massive pig die offs in China right now, ostensibly from PRRS (Porcine Reproductive Respiratory Syndrome), and that also has scientists concerned. If this is, in fact, PRRS, the virus appears to have mutated to a more virulent form.
It is unclear when or if that virus will pose a threat to humans.
Agencies like the WHO and the FAO have their hands full tracking and researching these emerging viral threats. Most will remain localized problems, resulting in small, though tragic outbreaks in humans.
It just takes one, however, that adapts well to humans and spreads easily, to ruin our entire day.
