Hidden 'super spreaders' spaces associated with dengue fever transmission: Study

A new study suggests that the number of hidden infections tied to a place or cases of infected people who show no symptoms could be the key indicator for dengue riskSo far for mosquitoborne diseases such as dengue fever the abundance of the insects in places where people gather has served as the main barometer for infection riskThe new study published in the journal PNAS Nexus found that 8 per cent of human activity spaces accounted for more than half of infections during a dengue outbreak And these super spreader spaces were associated with a predominance of asymptomatic cases or 74 per cent of all infectionsThats the complicated nature of this virus We have underestimated the role of asymptomatic cases in spreading dengue Gonzalo VazquezProkopec associate professor of environmental sciences at Emory University saidSymptomatic cases represent only the tip of the iceberg he addedGenerally about 50 to 70 per cent of dengue cases are asymptomatic making detection by public health officials impractical but the study reveals that asymptomatic cases are tied to a third of transmissionThe lesson is that we need to focus on prevention of dengue outbreaks VazquezProkopec said The interventions for dengue for decades have been reactive Simply reacting by closing a net around reported cases of the disease however will fail to contain an outbreak because thats missing the super spreadersFor the study the researchers wanted to determine the role of asymptomatic cases People without symptoms may continue to go about their daily routines unknowingly infecting any mosquitoes that bite them which can then later spread the virus to more peopleThe study involved 4600 people in two different neighbourhoods in the Amazonian city of Iquitos in Peru a dengue hotspotThey were surveyed three times a week about their mobility This data was used to map activity spaces such as residences churches and schoolsBlood analyses confirmed a total of 257 symptomatic cases of dengue during the sixyear study period That led to investigations of other participants whose activity spaces overlapped with the symptomatic cases More than 2000 of these locationbased contacts were confirmed by blood tests to have dengue infections and more than half of them reported not having any noticeable symptomsThe results pinpointed the role of asymptomatic super spreaders in a dengue outbreak A small number of the activity spaces or 8 per cent were linked to more than half of the infections and most of the cases associated with those places were asymptomaticWe found that the mosquito numbers in a location alone is not a predictor of the risk of infection VazquezProkopec saidInstead risk prediction for a location requires a cascade of circumstances a high number of asymptomatic cases frequenting the location combined with high levels of mosquitos and high numbers of people who are not immune to the particular serotype of dengue virus that is circulatingFor diseases that are directly spread from one person to another like Covid19 what matters is who you were near he said But in the case of dengue what matters most is where you wentAlso Read Dengue virus has evolved dramatically to be more severe in India StudyThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever