Economic Downturn Results in Tickborne Disease Surge

The emergence of zoonoses is due both to changes in human activities and to changes in their natural wildlife cycles. One of the most significant vectorborne zoonoses in Europe, tickborne encephalitis (TBE), doubled in incidence in 1993, largely as a consequence of the socio-economic transition from communism to capitalism and associated environmental changes.

Elinor R Godfrey and Sarah E Randolph of the Department of Zoology at the University of Oxford conducted a study to test the effect of the current economic recession, unemployment in 2009 and various socio-economic indices were compared to weather indices (derived from principal component analyses) as predictors for the change in TBE case numbers in 2009 relative to 2004-08, for 14 European countries.

The researchers report that the greatest increases in TBE incidence occurred in Latvia, Lithuania and Poland (91 percent, 79 percent and 45 percent, respectively). The weather was rejected as an explanatory variable. Indicators of high background levels of poverty, e.g. percent of household expenditure on food, were significant predictors. The increase in unemployment in 2009 relative to 2008 together with 'in-work risk of poverty' is the only case in which a multivariate model has a second significant term.

Godfrey and Randolph conclude that background socio-economic conditions determine susceptibility to risk of TBE, while increased unemployment triggered a sudden increase in risk. Mechanisms behind this result may include reduced resistance to infection through stress; reduced uptake of costly vaccination; and more exposure of people to infected ticks in their forest habitat as they make greater use of wild forest foods, especially in those countries, Lithuania and Poland, with major marketing opportunities in such products. They say that recognition of these risk factors could allow more effective protection through education and a vaccination program targeted at the economically most vulnerable. Their research was published in Parasites & Vectors. 

Reference: Godfrey ER and Randolph SE. Economic downturn results in tick-borne disease upsurge. Parasites & Vectors 2011, 4:35doi:10.1186/1756-3305-4-35.