A new study proposes that people infected with dengue virus who show no symptoms of the disease are likely the major transmitter of dengue fever.
Experts have previously assumed that people who exhibited mild to no symptoms of the disease have a comparatively small contribution to the transmission of dengue virus. The study, published on May 3 in PLOS Pathogens, concludes otherwise.
Public health surveillance systems might fail to detect dengue infection from people with no prevalent symptoms of the dengue fever. Also, these people are unlikely to submit themselves for medical checkups and appropriate treatments.
The researchers, led by Quirine ten Bosch, a graduate fellow of the Eck Institute for Global Health at Notre Dame, used mathematical modeling to calculate what fraction of dengue transmission might have been contributed by asymptomatic people.
The mathematical equation included computations on the amount of virus in the blood within the different stages of the infection, the severity of symptoms during previous infections, and the proportion of infections in clinical consultation.
The numerical approximation showed that more than 80 percent of dengue virus could be linked to those individuals who are asymptomatic and who did not undergo medical treatment.
Furthermore, computations revealed that a quarter of dengue virus transmission is caused by mosquitoes that bit individuals who are already infected but symptoms are not yet showing. In this case, their symptoms might occur late, and medical interventions could no longer prevent the spread of the virus.
Primary Source Of Dengue Fever
Alex Perkins, the senior author of the study and Eck Family assistant professor of biological science at the University of Notre Dame, says the study equipped them with a clearer perspective of the magnitude to which asymptomatic people could contribute largely to the dengue virus transmission.
"Our results indicate that it might be necessary to shift emphasis toward more proactive disease prevention strategies that do not rely as strongly on responding to detected cases," Perkins explains.
Dengue Fever On A Global Scale
The World Health Organization states that dengue is a mosquito-borne infection. The virus is transmitted by female mosquitoes, which are also transmitters of chikungunya, yellow fever, and Zika infection.
The virus commonly thrives throughout the tropics, but the amount of rainfall, temperature, and unplanned rapid urbanization in a region could contribute to the spreading of the virus.
WHO says the actual dengue cases are underreported, but a recent estimate indicates that there are 390 million people who contracted the virus each year. Another estimate showed that 3.9 billion people in 128 countries are at risk of contracting dengue virus.