That virus again

The dreaded bird flu is here again, less than a year after India formally declared itself free of the contagious disease that is caused by the highly pathogenic H5N1 avian influenza virus. This has come as no surprise as the danger of its reappearance has been lurking all the time, especially because the virus has been active in many neighbouring countries, including China, Pakistan, Myanmar and Bangladesh. Also known was the fact that the north-east is the most vulnerable area because of its porous border with the bird flu-infected Bangladesh and Myanmar. In any case, this pernicious malady has a tendency to recur in countries where it has surfaced in the past. This has happened in 20 of the 25 countries which have been hit by bird flu in the last eight months. The persistent nature of the H5N1 virus is borne out also by the fact that, despite the global efforts to eradicate it, it has endured for nearly a decade since it first appeared in Hong Kong in 1997. Where India is concerned, though the government may manage to contain the problem to the affected area in East Imphal district of Manipur, as it did in Maharashtra in February 2006, that will not be the end of the fight. In fact, the risk of re-emergence will be even greater when migratory birds start visiting India in the winter.

What is needed, therefore, are preventive (like barring the inter-border movement of poultry products) as well as prophylactic (vaccination) measures, at least in vulnerable areas such as the border belt and the areas around the water bodies visited by migratory birds. Surveillance alone may not be enough. For, even in Chingmeirong village of Manipur, the site of the present bird flu outbreak, it took the authorities over two weeks to confirm and notify the occurrence of the disease despite intensive surveillance being in force. Under favourable conditions, the infection could have travelled quite far in that time.

It is therefore advisable to consider the suggestion of the Poultry Federation of India and vaccinate all the poultry and other domesticated birds in the susceptible areas. Though many people argue against preventive vaccination, usually on the plea that it might lead to the development of immunity in the virus against the available infection inhibitors (oseltamivir and zanamivir), nothing of the sort has happened in countries like Vietnam which have tried this solution. The other argument against vaccination, that it might hurt poultry exports, is equally untenable as several other poultry product-exporting countries have also been using the vaccine. In any case, exports account for less than 1 per cent of the total poultry production.

The authorities should also consider the system of "zoning", whereby non-affected areas could be declared as disease-free zones for sourcing export supplies. There are globally accepted norms for doing so. Zoning is not new in India, as such a system is already in vogue for some other animal diseases, notably the food-and-mouth disease that affects bovines. What needs to be emphasised is that all the required steps should be taken seriously; should the H5N1 virus mutate into a human-infecting form and cause a pandemic, the consequences could be catastrophic.