The finding that the increase in temperature in Europe has brought about changes in mosquito-related diseases; said the president of Ecodevelopment SA Spyros Mourelatos in a webinar organized on climate change and vector-borne diseases.

According to Mr. Murelato, virtually all vector-borne diseases are affected by climate, and global warming will likely expand the geographic spread of vectors and the season of disease transmission.

“The expected increase in rainfall will create more breeding grounds for transmitters while some areas may become too warm for transmitters to survive,” Mourelatos said. He clarified, however, that directly linking any effects of climate change is complex as other factors such as land use changes and human movement also play a role. “The sooner we act to adapt and deal with the effects of climate change, the better,” he said.

Rising temperatures are changing the population of the tsetse fly

According to Florence Fouque, who since 2014 heads the Vector Environment and Society Unit of the World Health Organization’s Special Program for Research and Training in Tropical Diseases (TDR), climate variables affect vector-borne diseases transmitters.

“What has been observed in recent years is that the density of the tsetse fly in some areas such as the Zambezi Valley is sharply decreasing while the temperature is increasing. Unfortunately, however, the situation is not similar in all areas since in Tanzania, the increase in temperature does not harm the tsetse fly, it simply changes its distribution and has an increased presence in some areas.”

Ms. Fook also referred to the increase in the number of dengue cases in Europe that are not imported, but indigenous cases.

“There were less than 20 cases around 2010 but in 2023, the number of cases is over 200, for all countries combined. In particular, we have basically three countries that are recording cases, which are France, Spain and Italy, but we are not sure at the moment that the increase in dengue cases is due to climate change.”

For Ms. Fook, there is always the unpredictability in some cases in relation to climate change in transmitters and the diseases they transmit. “Even if we have good models and good modeling, we can’t predict everything,” he said, noting that the impact of climate change depends not only on the biology of transmitters but also on socioeconomic factors and human behavior and response.

“The health system must be prepared to face the unexpected effects of climate change by developing a preparedness plan,” he stressed.

Climate change and transmitters

The effects of climate change, which in turn increase the incidence of mosquito-borne diseases, water-borne diseases, air-borne diseases and many other diseases, said Charles Mbogo of the Pan-African Mosquito Control Agency.

“We find that climate change is affected by economic, social and environmental factors. And I mentioned floods, phenomena like drought, desertification, deforestation, loss of agricultural productivity and land degradation that has happened in many places. “Once you interfere with the fauna, the natural vegetation, the transmitters that thrive there are likely to change, as happened in the highlands of Kenya,” he said.

For Mr Bogo, global warming is also likely to affect public health through outbreaks of food insecurity and malnutrition, such as in the floods in Nigeria and also in Kenya.

“We find that these factors, economic, social and environmental, are major contributors to malaria and other mosquito-borne diseases and can reduce the potential for any response by public health systems because global warming at this level affects the set of diseases caused by transmitters. What do I mean by that? I mean that health systems, because of the multitude of disease outbreaks involving transmitters, will not have the capacity to adequately deal with these events.” Mr. Bogo finally pointed out that the increasing risk of many human cases will exceed the capabilities of public health systems and so will governments.

Sandra Gewehr, biologist, president of the European Mosquito Control Association and director of Research and Development of Eco-development SA, referred to the lack of a single policy for mosquitoes.

“The basic condition for preparedness is the surveillance of factors such as human cases, indicator animals and entomological parameters” he underlined.