The virus responsible for the dengue infection can become more virulent in higher temperatures, a new study has found.
The study, conducted by the Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala and recently published in The Federation of American Societies of Experimental Biology, looked at the effect of temperature on virus virulence in animal models.
What does the new study indicate?
The study found that the virus, when grown at a higher temperature was significantly more virulent than the virus grown at a lower temperature. “In a mouse model, the virulent strain induced enhanced viremia and aggressive disease with a short course, hemorrhage, severe vascular permeability, and death,” the study said. Viremia is the presence of virus in the blood stream.
Usha A, a Bengaluru-based entomologist says that there are four dengue virus serotypes- DEN-1, DEN-2, DEN-3, and DEN-4.
“Infection with one serotype gives life-long immunity against infection with that particular serotype. However, we cannot say that the persons will not get infected again- there are chances of infection with another serotype. When a person who has been infected with one serotype in the past gets infected with another serotype later on, the complications are higher,” she says, adding that among the four serotypes, DEN-2 is considered more virulent.
Usha adds “As an entomologist, what we know is that temperature fluctuations, even by one degree Celsius, increases the vectorial capacity of the dengue mosquito to transmit the disease- this has been pointed out by many studies.”
“According to the new insight, even the virus changes its activity and becomes more virulent with temperature fluctuations. However, this is only a sample study and is restricted to one particular area. Even the complications in one individual differ with their unique immunological character. If the person has any comorbid conditions, for instance, chances of complications are higher,” Usha said, adding further studies are required.
What are the implications of the new study?
Dr Narayanaswamy S, founder and medical director at Athreya Hospital, Bengaluru, while pointing out that recently there has been a surge in the number of dengue cases and cases of dengue-like illnesses, says that the study has profound implications for dengue management in terms of preventive and curative efforts.
“This study has unearthed a significant finding: dengue becomes more severe in animal models when exposed to higher temperatures. The warmer conditions expedite the virus growth within mosquitoes, potentially leading to faster transmission to humans,” he says.
What is dengue?
Dengue is a mosquito-borne viral disease and typical symptoms include a high-grade fever with chills, sore throat, headaches, rashes on the body, muscle and joint pains and fatigue.
How to prevent dengue?
The best way to prevent dengue, a mosquito-borne infection, is to stay away from getting bitten by mosquitoes- by covering up your body, using mosquito repellents and making sure that all mosquito breeding grounds in your surroundings- such as a vessel filled with stagnant water, a discarded tyre filled with stagnant water or any container that can hold water – are disposed of.
According to the Centres for Disease Control and Prevention (CDC), the dengue mosquito lays its eggs on ‘walls of water-filled containers in the house and patio’ and does not lay eggs in ditches, drainages, canals, wetlands, rivers or lakes and pouring chlorine into these habitats is useless and may only harm aquatic life.
Takeaways
- A new study conducted in animal bodies has found that the virus responsible for dengue becomes more virulent under higher temperatures.
- Dengue becomes more severe in animal models when exposed to higher temperatures.
- The warmer conditions expedite the virus growth within mosquitoes, potentially leading to faster transmission to humans.
