The Heat Is Online

Encephalitis Spreads in Russian Summer Heat

Agence France-Presse, July 11, 1999

Searing summer temperatures in Russia have brought a new threat apart from heatstroke -- a proliferation of ticks carrying a deadly encephalitis virus. Already a score of people have died from the disease and tens of thousands have consulted doctors after being bitten by the ticks, blood-sucking arachnids which lie in wait in woods and grasslands to fasten on to passing victims. The problem is well-known in Asiatic Russia where vaccines are obtainable. Medical services admit that such protection is non-existent in the rest of the country.

Meanwhile residents inMoscow andSaint Petersburg, unaware of the danger, stroll through the woods bare-headed, in shorts and short-sleeves, inviting attack.

Cases of tick-borne encephalitis have been reported in the Saint Petersburg region, from Karelia further to the north, and from Kostroma on the Volga. There have also been eight deaths in Siberia. According to the latest figures of the federal epidemiological service, the number of cases recorded in May was already 60% greater than the year before. "This is only the beginning," warned the head of the service Galina Lazikova.

In 1996, the last year of a tick plague, 166 people died after a tick bite, which though painless can cause fever, meningitis or paralysis of the nervous system, bringing death by asphyxiation. The ticks are most common in June, Lazikova said, and with the period of encephalitis incubation lasting from eight to 23 days, the worst would be known by the end of July.

Chief epidemiologist from the Novosibirsk region, Nikolai Mozheysky, blamed the unexpected and early heat wave, which began in May and is still going on, with temperatures in central Russia reaching 33C. "There is also a fall in the population of rodents, the ticks' main prey, which could explain why they are more prone to attacking people now," he added. Other specialists say changed economic and social conditions are a key factor in the spread of encephalitis.

Central European encephalitis virus (CEEV), the geographic distribution of which includes western Europe to the Urals, is transmitted principally by Ixodes ricinus ticks. The very closely related Russian Spring-Summer encephalitis virus (RSSEV), the geographic distribution of which includes Siberia and areas to the west as far as the Urals, is transmitted principally by Ixodes persulcatus ticks. The distribution of these two viruses is dependent on the distribution of the host tick species. An Austrian vaccine prepared with CEEV is available and may confer protection against infection with RSSEV as well as against CEEV.