Monash study urges coordinated action to fight mosquito-borne diseases

Prevention measures, including vector control, vaccine deployment and cutting greenhouse gas emissions to limit global warming are critical to counter the growing burden of mosquito-borne diseases in a changing climate, according to a new paper by Monash University researchers.

The review, published today in Science Advances, examines the complex ecological, epidemiological and socioeconomic factors that influence the transmission of malaria and dengue.

Malaria is a serious, life-threatening disease caused by a parasite that is typically spread to humans through the bites of infected female Anopheles mosquitoes.

Dengue is caused by a virus that is transmitted to humans through the bites of infected female Aedes mosquitoes.

Across the world, there are close to 300 million cases of malaria and almost 400 million dengue infections every year.

Lead researcher Dr Toby Cumming, a research fellow in the Health and Climate Initiative at the Monash School of Public Health and Preventive Medicine, said properly understanding the drivers of disease transmission is key to identifying effective public health responses.

"As climate change increases temperatures and alters rainfall patterns, this expands the areas with climatic conditions in which Anopheles and Aedes mosquito populations can thrive," Dr Cumming said.

While the influence of these climate factors is complicated – relationships are non-linear, effects are seasonal, there is substantial local variability – they have broadly similar impacts on malaria and dengue transmission.

Yet over the last century, during a time of unambiguous warming, rates of malaria have declined while rates of dengue have risen."

Dr. Toby Cumming, research fellow, Health and Climate Initiative, Monash School of Public Health and Preventive Medicine

The researchers highlight non-climate factors that help explain the different trajectories of the two diseases. 

Mosquito control interventions and drug therapies have driven major gains in reducing malaria transmission, while increasing urbanization has favored Aedes mosquitoes and hence the spread of dengue, for which no therapeutics are available.

Dr Cumming emphasized that there is no room for complacency: although malaria is in long-term decline, global incidence has risen 8.5 per cent over the past decade.

"Recent malaria trends and the rapid growth in dengue are both serious concerns, and we must escalate our prevention and control efforts," he said. 

Novel preventive interventions for dengue are emerging that include vaccines and innovative vector control strategies, such as the introduction of the bacterium Wolbachia into Aedes mosquito populations, which reduces the mosquitoes' ability to transmit dengue, developed by the World Mosquito Program, a not-for-profit group of companies owned by Monash University.

"Ultimately, our research reinforces the need for a coordinated approach, encompassing interventions to address the many climate and non-climate factors that contribute to the spread of mosquito-borne disease," Dr Cumming said.