NEW YORK — The spread of avian flu to Africa and Europe, although expected, is unwelcome news. In the last few weeks the disease has reached several states in northern Nigeria and Niger. Together with other countries in West Africa, they are on the bird migratory route from Central Asia and the Middle East, where the virus has already surfaced.
The possibility that the virus will spread into other African countries demands that early detection and rapid-response mechanisms be put in place to contain what may become a devastating human pandemic.
Experience has shown that close contact with diseased or dead poultry is the primary means of human exposure to the virus. This makes the situation all the more serious for many African countries, since most village households maintain free-ranging flocks of poultry as a source of income and food.
At least 160 people have become infected with the disease worldwide through close contact with sick birds. Half of those diagnosed with the infection have died. It is estimated that more than 40,000 chickens have already died on a commercial poultry farm in Nigeria.
The presence of the avian flu virus in poultry in Nigeria is its first reported appearance on the continent. This poses serious risks to human health and livelihoods not only in Nigeria but also in other nations along the so-called Black Sea-Mediterranean flyway. If the virus has been found in Nigeria and Niger, it probably is present already in other African countries as well.
More than 80 percent of African families keep domestic chickens and other birds at home. Therefore, if the virus mutates and starts affecting humans, the effects could be devastating, particularly for people whose immune system has been weakened from other infections such as HIV or malaria.
Among all the avian influenza viruses that have infected humans, H5N1, the one found in Nigeria and Niger, is the one that has caused the highest number of deaths in humans. Because human immune systems cannot fully protect against these viruses yet, if H5N1 gains the capacity to infect humans, it could rapidly spread from person to person and lead to a global outbreak.
Should a pandemic start, it would be nearly unstoppable. It would rapidly overwhelm already weak health services, particularly in Africa. The consequences would not only be huge loss of life but also massive economic and social damage due to the disruption of interconnected systems of travel, trade and finance.
As things stand now, it is crucial to develop public-information campaigns warning populations about high-risk behavior such as slaughtering, defeathering and butchering diseased poultry. These campaigns must be targeted at high-risk groups with the aim of changing behavior.
African countries have serious deficiencies in their veterinary and health-care services and are unable to cope with the demands of a rapidly spreading pandemic. Nigeria remains one of the world’s last footholds of polio, partly due to local leaders’ having rejected the vaccination of children in the past on the grounds that the vaccine was unsafe.
The health-care workers now carrying out polio-eradication efforts in Nigeria could be rapidly retrained to look for cases of flu and to identify their source. Parallel to these actions, public health systems at the local and national levels must strengthen surveillance and diagnostic methods as well their logistic approaches to the spread of the disease.
Nobody can predict when a pandemic might occur. If clusters of patients closely related in time and place are diagnosed with clinical symptoms of influenza, it may indicate that human-to-human transmission may be taking place. Public health systems in all countries should be ready to respond adequately to this most important health challenge.