Once dengue was found in only nine countries, today the disease is endemic in more than 100 — putting more than half the world's population at risk, according to the World Health Organization.
Dengue fever outbreaks have been reported across countries killing more than 1,000 people and infecting hundreds of others. Bangladesh has been the worst outbreak with five times as many people getting infected in August than the whole of 2018. Fifty-seven people have already died from the mosquito-borne disease in Bangladesh alone this year.
Dengue is a seasonal, mosquito-borne disease commonly found in hot, wet regions of the tropics and subtropics during the rainy months.
The story is somewhat similar in Cambodia, Laos, Malaysia, Singapore, Sri Lanka, Thailand, and Vietnam. All these places have reported higher than normal cases of disease and deaths related to dengue, as compared to 2018. In fact, Philippines has declared a national dengue epidemic — 1,107 people have died there since the start of the year and more than 250,000 have been infected, CNN reported.
According to scientists, hotter and wetter weather brought on by climatic changes has created ideal conditions for female mosquitoes to lay eggs which, paired with rapid urbanization in many Asian countries, are pushing populations to live in close proximity with disease-carrying insects.
Furthermore, unprepared health services and circulation of the virus have created conditions for an outbreak of epidemic proportions.
Interestingly, while dengue was once found in only nine countries, today the disease is endemic in more than 100 — putting more than half the world's population at risk, according to the World Health Organization (WHO).
There have been numerous studies on the link between climate change and mosquito-borne diseases with experts saying that rising temperatures are triggering more extreme weather events and a warmer, wetter world could put us at greater risk of vector-borne diseases — those transmitted by mosquitoes, ticks or other organisms.
One recent study, published in PLOS suggests that 1 billion more people might be exposed to mosquito-borne disease by 2080 as temperatures continue to rise with the climate crisis, revealed the CNN report.
Speaking about the same, Dr. Rabindra Abeyasinghe, Coordinator of Malaria, Other Vector borne and Parasitic Diseases, at the WHO's Regional Office for the Western Pacific said that as the average temperature increases, the survival of mosquitoes and replication of pathogen with mosquitoes becomes more efficient.
Furthermore, the CNN report says that erratic weather has made it harder to predict outbreaks around the world. Dr. Rachel Lowe of the London School of Hygiene and Tropical Medicine told CNN that with climate change altering weather pattern across the globe, predictable extreme events have become rare and these changing patterns can cause the dengue season to shift "making it harder to know when and where an epidemic might occur."
According to scientists, as the planet gets warmer, mosquito-borne diseases will continue spreading farther north. A study published in Nature Microbiology found that rising global temperatures caused by the climate crisis could see the female aedes aegypti mosquito which carries dengue – along with other diseases such as chikungunya, yellow fever and Zika – migrate to areas where it was not endemic before.
Modern lifestyle is also to blame, the report suggests, saying that people were not able to travel such great distances earlier, and when they do that now, they may not bring back just souvenirs from the trip but mosquito species which can establish colonies in new places.
With no vaccine at hand, the main form of disease prevention to date has been mosquito control through the large-scale spraying of insecticides. However, the dengue virus is evolving as well, becoming resistant to pesticides in several countries.
Besides, the four strains of the virus mean it is four times more difficult to get on top of the disease. However, nonprofit initiatives like the World Mosquito Program has seen quite a bit of success in its initiative that uses a naturally occurring bacteria to reduce the ability of mosquitoes to transmit diseases such as dengue.
Lowe's team is looking at how countries with dengue can set up early warning systems to predict future abnormal climate conditions and help prepare for potential outbreaks, thus making inroads into the climate factor as well.
Source: CNN
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