The comeback killer

2019-03-07 06:03:08

By Debora MacKenzie EUROPE faces “a serious risk of an uncontrollable resurgence of malaria”, warns the WHO in a new report. Drainage, drugs and insecticides eradicated malaria from the whole of Europe by the 1960s. Now civil disorder and irrigation threaten to bring it back unless controls are stepped up, the report says. These concerns come hard on the heels of fears that malaria may move north thanks to global warming. In a report for health officials from its European region, meeting this week in Florence, the WHO says that cases in the European Union jumped from 2882 in 1981 to 12 328 in 1997. Despite access to good medical care, up to 7 per cent of those people die because European doctors may not recognise the unfamiliar disease until it is too late. More European travellers are bringing malaria back from countries where it is endemic, and the big fear is that local mosquitoes could acquire the parasite from such travellers and re-establish a local chain of transmission. Three recent cases in Luxembourg and two in New York have fuelled concern over air travel as a means of reintroduction. The cases in Luxembourg all occurred within a few kilometres of the country’s international airport, and were probably caused by mosquitoes stowing away on aircraft arriving from the tropics (New Scientist, 11 September, p 14). The migration of refugees during regional conflicts, a massive increase in the 1970s in irrigation canals where mosquitoes can breed, and the demise of public health programmes with the collapse of Communism have led to a “dramatic resurgence” of the disease, says the WHO. This has particularly affected former Soviet states bordering endemic areas such as Afghanistan. The report states that Azerbaijan and Tajikstan are seeing large-scale epidemics, with smaller epidemics in Armenia and Turkmenistan. Travellers from those areas probably infected the mosquitoes that gave two Russians malaria this month in the city of Ryazan, 180 kilometres southeast of Moscow. The two had never been outside the region. Similar cases occurred for the first time since the 1960s in Russia last year, and surveys have revealed infected local mosquitoes as far north as Moscow. In Turkey, malaria was almost eliminated by 1989. But a major irrigation project in the southeast of the country caused cases to jump nearly tenfold between 1990 and 1994. A massive effort to control that epidemic is almost solely responsible for a fall in the total number of cases in Europe since 1996, but the control is tenuous. Turkey’s tourist boom means that malaria could start to pose a risk for western Europe. The WHO thinks that good medical care, vigilant surveillance and chilly winters will prevent malaria from re-establishing itself in northern Europe, despite the existence of mosquito species able to carry it. But the species that live in southern Europe are better at maintaining the parasite. There were outbreaks of malaria that were spread by local mosquitoes in Corsica in 1970, and in Bulgaria in 1995, while in 1997 an Italian caught the disease from a local mosquito. “The risk for the reappearance of the disease in some areas of southern Europe, where more efficient vectors are present, is real,