Bird Flu: The Next Pandemic?
The world is still recuperating from the onslaught of the severe acute respiratory syndrome (SARS) that killed 774 persons and spread to almost every corner of the globe in 2003-04. The World Health Organisation (WHO) warns that we are again closer to experiencing the next pandemic, Bird Flu (Avian Influenza). David Heymann of WHO recently observed that the ‘world is at great risk of a new pandemic of deadly bird flu, but is ill-prepared to handle it’. Another senior WHO official, Klaus Stoehr, on the sidelines of the Inter-Science Conference on Anti-microbial Agents and Chemotherapy (ICAAC), urged governments, pharmaceutical companies and the science community to speed up the production of anti-flu vaccines.
Avian Influenza or Bird Flu is an infectious disease of birds (waterfowl) caused by type ‘A- strain’ of the influenza virus. The disease was first reportedly identified in Italy more than a century ago. From 1918 to 1919, a virulent flu pandemic killed millions worldwide. During a 1983–1984 epidemic in the US, the H5N2 virus, a subtype of A-strain, caused nearly 90% mortality in poultry within six months of the outbreak. During a 1999–2001 epidemic in Italy, the H7N1 virus, another virulent sub-type of A-strain, more than 13 million birds died or were destroyed within nine months of the outbreak. The last pandemic was 36 years ago, the Hong Kong flu of 1968. It is observed that viruses of low pathogenicity can mutate into highly pathogenic viruses within a short period circulating among the poultry population.
It is more or less determined that among the 15 or so different strains of the virus, the H5N1 strain is infecting humans and causing deaths. The first documented human infection occurred in Hong Kong in 1997, when the H5N1 strain, the most virulent among all subtypes, caused severe respiratory disease that killed six people and affected 12 others.
Last year in November, Thailand had first reported cases of what it calls chicken cholera. Soon after, at least nine Asian countries experienced bird flu outbreaks in their present incarnation. Some 31 people died from the infection in 2004 in Thailand and Vietnam, and millions of poultry have died or been culled across Asia. In Thailand, with the death of a young girl on October 25, the total number of victims rose to 12. The bird flu virus has hit 280 areas in 41 provinces in Thailand. The last test results confirmed that the girl who died in northern Sukhothai province had been infected with the deadly H5N1 strain. In Vietnam, altogether, 19 people have died of the epidemic since the outbreak. The country has suffered the worst outbreak of H5N1 bird flu so far in Southeast Asia. The type of bird flu that killed another person (20th victim) has yet to be formally identified. Investigations showed that close contact with live infected poultry was the source of human infection. However, the WHO has ascertained that no human-to-human transmission is occurring so far.
The spread is not limited to humans and poultry alone. The bird flu virus has spread like wildfire in most Southeast Asian countries, affecting dogs, tigers, and other animals. For the first time in Thailand, the virus was found in a dog and many tigers. The Thai government killed 147 tigers at the Sri Racha Tiger Zoo, where several tigers died from bird flu after being fed raw chicken, primarily to wipe out the bird flu virus.
Other Southeast Asian countries have been affected by the bird flu: Cambodia, Indonesia, China, Laos, South Korea, Japan, and Taiwan. The disease has virtually devastated the poultry industry. Even considering the transboundary spread, Malaysia has deployed troops on its border with Thailand to check the smuggling of poultry into northern Kelantan state, even though Malaysia has yet to have a human infection of the disease.
Are South Asian countries prepared for this pandemic? Perhaps not. All South Asian countries are highly vulnerable to any epidemic. During SARS, with media pressure, the government of India took some preventive approaches, such as checking at the Port and other immigrant points. However, the emerging market in India, which attracts the outside world, is susceptible to such infectious diseases. The most astonishing aspect was that the bird flu spread to Pakistan, where two million chickens died due to the infection. Fortunately for India, it escaped from the wrath of the virus.
Despite the optimism of WHO members to have tackled SARS, it is possible to crop up again. The growing environmental changes could trigger a new variety of infectious diseases in developing countries, where a major chunk is poor. Half of the Afro-Asian countries are struggling with numerous existing known and mysterious diseases with very little care from the world community. Bird Flu will add another distress to them. The need of the hour is to be better prepared with preventive measures than waiting for the pandemic to happen.