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. 2022 Oct 7;7(10):287.
doi: 10.3390/tropicalmed7100287.

Dengue Incidence and Aedes Vector Collections in Relation to COVID-19 Population Mobility Restrictions

Sinnathamby Noble Surendran  1 , Ratnarajah Nagulan  2 , Annathurai Tharsan  1 , Kokila Sivabalakrishnan  1 , Ranjan Ramasamy  1
Affiliations

Dengue Incidence and Aedes Vector Collections in Relation to COVID-19 Population Mobility Restrictions

Sinnathamby Noble Surendran et al. Trop Med Infect Dis. .

Abstract

Contrary to expectation, dengue incidence decreased in many countries during the period when stringent population movement restrictions were imposed to combat COVID-19. Using a seasonal autoregressive integrated moving average model, we previously reported a 74% reduction in the predicted number of dengue cases from March 2020 to April 2021 in the whole of Sri Lanka, with reductions occurring in all 25 districts in the country. The reduction in dengue incidence was accompanied by an 87% reduction in larval collections of Aedes vectors in the northern city of Jaffna. It was proposed that movement restrictions led to reduced human contact and blood feeding by Aedes vectors, accompanied by decreased oviposition and vector densities, which were responsible for diminished dengue transmission. These findings are extended in the present study by investigating the relationship between dengue incidence, population movement restrictions, and vector larval collections between May 2021 and July 2022, when movement restrictions began to be lifted, with their complete removal in November 2021. The new findings further support our previous proposal that population movement restrictions imposed during the COVID-19 pandemic reduced dengue transmission primarily by influencing human-Aedes vector interaction dynamics.

Keywords: Aedes aegypti; Aedes albopictus; COVID-19; Jaffna; Sri Lanka; dengue incidence; dengue transmission; dengue vectors; mosquito vector–human interactions; population movement restrictions.

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Conflict of interest statement

The authors declare that they have no conflict of interests.

Figures

Figure 1
Figure 1
Map showing (a) the location of Sri Lanka in relation to India; (b) the boundaries of the 25 districts including Colombo, Gampaha, and Jaffna districts that have high dengue incidence; and (c) the location of the city of Jaffna within the Jaffna district.
Figure 2
Figure 2
Country-wide predicted and actual numbers of dengue cases in Sri Lanka. Colour coding for periods A, B, and C is the same as in Table 1.
Figure 3
Figure 3
Predicted and actual numbers of dengue cases in relation to rainfall in the Jaffna district. Colour coding for periods A, B, and C is the same as in Table 1.
See this image and copyright information in PMC

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