About My Health Careers Internship MedBlogs Contact us
Medindia LOGIN REGISTER
Advertisement

Dengue More Likely to Spread in Hot Weather

by Chrisy Ngilneii on December 2, 2017 at 11:46 AM
Font : A-A+

Dengue More Likely to Spread in Hot Weather

Dengue virus grows and spreads in mosquitoes faster at higher temperatures, but slows when temperatures are lower or fluctuate, suggesting that local weather conditions could have a big influence on dengue fever outbreaks.

The findings could help people prevent outbreaks during warm periods by reducing their exposure to mosquitoes or controlling mosquito numbers.

Advertisement


"Weather reports should be considered for early warning systems," says one of the study's authors, Xiao-Guang Chen from the Southern Medical University in Guangzhou, China. "If the outdoor temperature is high for a sustained period, dengue prevention strategies should be a priority."

An estimated that 390 million people are infected each year with dengue virus, which can cause serious illnesses such as dengue hemorrhagic fever and dengue shock syndrome. The virus is transmitted to humans through mosquito bites. It replicates during an initial incubation period beginning in the mosquito's gut, before spreading to reach its salivary glands. During a bite, the mosquito then transmits the virus in its saliva.
Advertisement

Many different factors can play a role in dengue fever outbreaks, including human population density and the numbers of mosquitoes in the region. Chen noticed that in China, outbreaks tend to be worse in southern regions, such as Guangdong Province - and that even within the province, some places are more prone to outbreaks than others. In one outbreak in Guangdong Province in 2014, a massive 96% of cases were concentrated in Guangzhou, for example, whereas Shenzhen, a similar city nearby, suffered very few cases.

During the 2014 outbreak, Guangdong Province was very hot, with a daily average maximum temperature of over 30°C from July to September. Chen and colleagues suspected that this may have played a role in the outbreak, and set out to see if temperature and temperature fluctuations affect the growth of dengue virus in mosquitoes.

The researchers infected mosquitoes with dengue virus, and kept them in the lab in incubators set at 18°C, 23°C, 28°C or 32°C. Another group of mosquitoes experienced temperatures that fluctuated each day (28°C for 14 hours, 23°C for 2 hours and 18°C for 8 hours). The researchers then determined how much the virus had replicated and whether it had spread throughout the mosquitoes' bodies.

The research team found that higher temperatures (23-28°C) resulted in more rapid viral growth and higher levels of virus. The hot conditions also led to a shorter viral incubation period, and the virus spreading throughout the mosquitoes' body to their salivary glands much earlier, meaning more infectious mosquitoes.

Under the coolest conditions, at 18°C, the virus grew very slowly and didn't spread to the salivary glands at all, reducing the chance that the mosquitoes could transmit it to humans. This might explain why cooler regions suffer less from dengue fever.

Interestingly, under fluctuating temperatures, the mosquitoes also showed lower levels of virus in their salivary glands compared with those kept at a constant 28°C. This suggests that even a temporary drop in temperature might be enough to reduce the chances that mosquitoes are infectious.

These findings may explain the different fates of Guangzhou and Shenzhen during the 2014 outbreak, as Shenzhen may experience greater temperature swings during the day, meaning it had less infectious mosquitoes. The scientists need to carry out further work to see whether this hypothesis is correct, and whether their results are applicable to mosquitoes in the wild.

Source: Eurekalert
Advertisement

Advertisement
News A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Advertisement
News Category
What's New on Medindia
Cochlear Implants may Consequently Drive Hearing Loss
E-cigarettes Use Linked to Erectile Dysfunction
Memory Loss - Can it be Recovered?
View all

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.

More News on:
Dengue Fever Dengue / Dengue Hemorrhagic Fever Mosquito Diseases Dengue and Homeopathy Chikungunya and Homeopathy Chikungunya Dengue Top 15 Do´s and Don´ts for Preventing and Managing Dengue Fever Dengue Vaccine 

Recommended Reading
Dengue
Dengue is a tropical disease caused by mosquitoes carrying the dengue virus. Symptoms include ......
Dengue / Dengue Hemorrhagic Fever
Encyclopedia section of medindia gives general information about Dengue and Dengue Hemorrhagic ......
Top 15 Dos and Don´ts for Preventing and Managing Dengue Fever
Dengue can be easily prevented and managed if you follow proper precautionary measures. Here we ......
Mosquito Diseases
Mosquito-borne diseases, like malaria, filaria, dengue, etc are common in places conducive of ......
Chikungunya
Chikungunya is a viral disease spread by mosquito bites; it causes fever, severe joint pain and rash...
Dengue Vaccine
Several dengue vaccines are under development. Dengvaxia, Sanofi’s live-attenuated tetravalent dengu...

Disclaimer - All information and content on this site are for information and educational purposes only. The information should not be used for either diagnosis or treatment or both for any health related problem or disease. Always seek the advice of a qualified physician for medical diagnosis and treatment. Full Disclaimer

© All Rights Reserved 1997 - 2021

This site uses cookies to deliver our services. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use