Wolbachia: a possible weapon for controlling dengue in Nepal

Abstract

Dengue, a mosquito-borne viral infectious disease, causes a high morbidity and mortality in tropical and subtropical areas of the world. In Nepal, the first case of dengue was reported in 2004 followed by frequent outbreaks in subsequent years, with the largest being in 2019 taking the death toll of six. It is reported that the number of dengue fever cases are soaring in Nepal spreading from the plains to more hilly regions. This might have serious public health implications in the future when combined with other factors, such as: global warming, lack of early detection and treatment of dengue, lack of diagnostic facilities, poor healthcare systems and mosquito control strategies. Nepal, thus, needs a cost-effective mosquito control strategy for the prevention and control of dengue. The Wolbachia-mediated biological method of the dengue control strategy is novel, economic, and environment-friendly. It has been successfully trialed in several areas of dengue-prone countries of the world, including Australia, Malaysia, Vietnam etc. resulting in significant reductions in dengue incidence. Given the lack of effective vector control strategy and weak economic condition of the country along with the persistence of climate and environment conditions that favors the host (Aedes mosquito) for Wolbachia, this approach can be a promising option to control dengue in Nepal.

Keywords: Dengue; Dengue control; Nepal; Outbreak; Wolbachia.

Fig. 1

Map of the landlocked Nepal bordered by India and China and showing the total number of confirmed dengue cases reported from different districts of Nepal from fiscal year 2014/2015 until 2019/2020. Data were retrieved from the Epidemiology and Disease Control Division, Department of Health Services, Ministry of Health and Population, Government of Nepal

Fig. 2

Confirmed dengue cases in Nepal recorded in each fiscal year starting from 2014/2015 until 2019/2020. Data were collected from Epidemiology and Disease Control Division, Department of Health Services, Ministry of Health and Population, Government of Nepal

Fig. 3

Vertical transmission of Wolbachia, its role in controlling dengue [23], and consequences within the infected host [24]. Note: red colored mosquitoes are infected with Wolbachia while green colored mosquitoes are uninfected. ♀ indicates female mosquito and ♂ symbolizes male mosquito