Climate Change Facilitates Spread of Chikungunya Virus

If climate change continues unchecked, the virus could even spread to southern Europe and the United States

The mosquito-borne viral disease Chikungunya is usually found in tropical areas according to Scientific Reports.

Researchers at the University of Bayreuth and the European Centre for Disease Prevention and Control (ECDC) in Stockholm have now discovered how climate change is facilitating the spread of the Chikungunya virus.

Even if climate change only progresses moderately, as scientists are currently observing, the risk of infection will continue to increase in many regions of the world through the end of the 21st century. If climate change continues unchecked, the virus could even spread to southern Europe and the United States. The researchers have published their findings in Scientific Reports.

It is the Asian tiger mosquito and yellow fever mosquito that infect humans with the Chikungunya virus. The climate affects the spread of a mosquito-borne virus in two main ways. First, it plays a crucial role in the geographical distribution of the mosquitos, which can only thrive in the long term if temperature and precipitation levels are high enough. Second, the virus replicates especially quickly in the body of the mosquito if the ambient temperature is high and remains relatively constant over the course of the day. For this reason, the risk of being infected with the Chikungunya virus has, until now, been mainly limited to tropical regions of Africa, Asia, and South America.

A team of researchers have investigated the climate conditions that facilitate the spread of the Chikungunya virus. They looked at the factors responsible for the climate conditions in regions that have traditionally had a high rate of infection. The data they collected enabled them to generate a world map displaying those areas where the risk of infection is particularly high. To this end, the researchers selected an approach based on machine learning that is often used in nature and wildlife conservation to develop models for the distribution of various species of plants and animals.

The virus would likely spread to countries in southern Europe as well as to the United States. According to the team’s predictions, the risk of Chikungunya is only likely to decrease slightly in two places: India and on the southern edge of the Sahara. The reason? Conditions in those places could become even too extreme for the mosquitos.