Global climate change is spawning deadly epidemics in Africa, writes Fred Pearce
For the second time in six months, the world is glimpsing the consequences of escalating climate change. After triggering the choking havoc of smoke from Indonesian forest fires last autumn, the worst El Nio for 50 years has in the past two months unleashed plagues of disease across East Africa in the wake of unprecedented dry-season rains and floods.
Cholera and malaria have claimed record numbers of victims across Kenya, Tanzania, Uganda and Somalia. Pests, such as a toxic insect known as the Nairobi fly, have proliferated. Locusts may be on the way. But most frightening of all comes an outbreak of Rift Valley Fever, a cattle disease that has decimated herds across eastern Kenya and southern Somalia and jumped the species barrier to kill hundreds of humans. It attacks with such ferocity that medics at first feared an outbreak of anthrax, and now speculate that they may have seen the emergence of a new super-strain of the virus that could take permanent residence in humans.
Rains in parts of Kenya in the past month have been 20 times the normal rate. El Nio, a climatic convulsion in the Pacific, has warped tropical weather fronts around the globe and left a band of intense rain over the country for weeks.
News reports in Kenya have concentrated on floods in Nairobi and the severing of the country’s main highway to Mombasa. But the real havoc has been caused in the northeast – a vast, normally arid land of cattle herders, which has effectively been cut off by floods for more than two months now.
Just before Christmas, news began to filter out of thousands of cattle deaths and a mysterious “bleeding disease” among humans. Louise Martin, an American disease consultant with the World Health Organisation (WHO) in Nairobi, flew out to stricken villages on Christmas Eve with helicopters bringing food aid.
“They were living, huddled with their animals, on small patches of dry land. They had no clean water and little food except for their diseased animals,” recalls Martin.
Victims of the bleeding disease, at first concentrated in the districts of Garissa and Wajir, were struck down literally overnight. They became delirious, began bleeding from ears, nose and mouth and died within hours. “I watched one 14-year-old girl, the same age as my own daughter, dying before my eyes,” says Martin.
Samples of blood collected by Martin and analysed in South Africa and Kenya revealed the Rift Valley Fever virus in both animals and humans. Last month the International Red Cross said the virus had killed “more than 450 people” so far and remained out of control. With dozens of settlements in the flooded region still not contacted, Martin refuses to be drawn on the death toll. Some suggest several thousand may be dead. And things could be even worse over the border in Somalia.
The disease has invaded a rural population without medical help and already severely weakened by malnutrition, tuberculosis, malaria and a range of parasitic diseases. The death rate from the disease appeared to be around 50% in humans and even higher in animals.
“One family I met had a herd of 200 goats one week, and only four left the next,” recalls Martin.
The virus spreads among animals via mosquitoes, rather like malaria. But, according to John Githule, human disease specialist at the International Centre of Insect Physiology and Ecology (Icipe) outside Nairobi, transmission is much faster.
The disease was first identified in 1931 in the Rift Valley in Kenya – hence its name. Until now, the largest known outbreak in humans was in Egypt during floods in 1977, when 600 people died. Some researchers have suggested the virus could have been responsible for biblical plagues in Egypt.
Humans, like animals, can be infected via mosquitoes. “The mosquitoes prefer to bite livestock, but will bite humans as a second best,” says Donald Klaucke, the WHO’s acting head in Nairobi. But he believes that human epidemics are largely caused by eating infected meat. Either way, with humans and animals huddled together against the floods, animal carcasses the only available food, and standing water causing an explosion in the number of mosquitoes, the people of north-eastern Kenya are a sitting target.
The Kenyan government, only recently getting back to work after the December elections, appears uninterested in the crisis. The country’s most respected newspaper, the Nation, complained last month that the government had yet to broadcast even basic advice to affected villages on how to minimise their risk of catching the disease. The Red Cross claimed the army had refused to provide helicopters to reach the stricken zone.
On January 14, at a meeting with the health ministry, Martin and WHO officials recommended immediate vaccination to prevent further spread of the disease among livestock. The Red Cross agreed. With the country holding stocks of vaccine for 300 000 animals there need have been no delay. But 10 days later, with reports of the disease spreading west and south, reaching the Magadi district just 50km from Nairobi, no decision on vaccination had been taken, says Martin.
Despite initial reports to the contrary, there is a human vaccine. It was developed secretly by the United States army in 1967 as part of experiments into the use of tropical diseases as biological weapons. The vaccine is offered to laboratory staff working with the disease, but according to Klaucke, has never been licensed for wider use. “The matter is a bit sensitive,” says a US army representative, without elaborating.
Whatever its original motivation, military research into exotic diseases could prove increasingly valuable. Hans Herren, director of Icipe, is in no doubt that remote regions could act as reservoirs for exotic diseases that could suddenly break out of their existing ecological niches because of a change in climate. In effect, humans could inadvertently unleash biological warfare on themselves.
Such epidemics may happen suddenly. And with many governments in Africa and elsewhere imploding, crippled by corruption and unable to keep either roads or hospitals open for business, the conditions for the return of major epidemics and the incubation of diseases new to humanity could hardly be better.