Now that summer is here, people are spending more and more time outside. Warm temperatures certainly make activities like swimming, hiking, jogging and picnicking more attractive. But forests and fields hold their fair share of dangers. Mice, mosquitoes and ticks can all spread serious diseases.
Zoonotic diseases (i.e. diseases which can be transmitted from animals to humans) are more common in warm weather. Besides through direct contact with animals or their excrement or the consumption of animal products, these diseases can also be transmitted by a vector (e.g. mosquitoes or ticks). See below for an overview of the zoonotic diseases which you are most likely to come into contact with when spending time outdoors.
Hantavirus garnered a lot of attention last year. The number of infections increased significantly, with 1,731 cases registered in Germany alone. Such epidemic years do recur time and again, depending on the size of the host population. The main hantavirus host in Germany is the bank vole. When a significant amount of food is available for the host, population numbers explode, causing the virus to spread. Infected animals excrete the pathogen in their urine, saliva and faeces. The disease can be transmitted to people through bites, but it is much more common for the pathogens to be inhaled. This might happen if you disturb contaminated dust when cleaning your garden shed.
TBE and Lyme disease
Tick season runs from March to October in Europe. During this period, people are more at risk for Lyme disease and tick-borne encephalitis (TBE), which are the two main tick-borne diseases. A TBE infection has two stages: A few days after the infection, patients experience non-specific flulike symptoms. This can be followed by meningitis or inflammation of the spinal cord, with some significant neurological issues. Ticks which carry the TBE virus are found only in specific regions (risk areas). These risk areas increase in size every year. Lyme disease can occur anywhere in central Europe and is triggered by Borrelia burgdorferi sensu lato bacteria. It can affect a number of organs, in particular the nervous system, skin and joints.
Diseases transmitted by mosquitoes
Mosquito population levels increase as the temperature goes up. Many regions are already reporting a mosquito plague. In Europe, mosquitoes are usually nothing more than just pests. However, more and more exotic species carrying dangerous pathogens are coming to these shores. They frequently stow away on aircraft or trucks heading to Europe, and then multiply when they arrive. The Asian tiger mosquito can transmit the zika, chikungunya and dengue virus, and has become a more common sight in Germany over the last few years. Nevertheless, the risk of being infected with these diseases in Europe is still low. Most cases of these diseases occur on trips to Asia or South America.