Vector–Borne infections in Pakistan do not come alone

Abstract

Background: From 1995 till 2019, around 147,200 cases of dengue infection and more than 800 deaths are reported from Pakistan. Vector of dengue virus is mosquito Aedes which is capable of transmitting other viral infections like Chikungunya, Zika, and Yellow Fever. From 2016–2018, Chikungunya infection was reported in 776 patients. With exponential increase in population and utilization of resources, it is important to eradicate this mosquito. Methods and materials: The present study provides an in-depth analysis on the factors, both virological and environmental, responsible for making dengue infection and its vector Aedes endemic in Pakistan. For this study, phylogeographic analysis of dengue, and Chikungunya virus was conducted using BEAST program. Coalescent GMRF Bayesian Skyride and Brownian Random Walk model was selected as continuous traits substitution model. Data was collected to relate vector distribution, and conditions responsible in increasing Aedes population. Results: The Chikungunya virus in Pakistan originated from the nodes of Madhya Pradesh and Rajasthan, India in 2015. This virus spread in Malir, Karachi and in Bahawalpur, Punjab, Pakistan in 2016. CHIKV strains of Pakistan resemble Indian strains due to their origin. Dengue strains are closely related to Indian and Chinese isolates. Pakistan being the fifth most populous country with density population of 281, Comoros2, the main cities of Karachi and Hyderabad in Sind province; Lahore and Faisalabad in Punjab province; and Islamabad/Rawalpindi of federal area and Peshawar of KP make up 22 million of population. Climatic change is not the only factor responsible for increased vector population in areas. Other global change factors including, growing population, agriculture, deforestation, and urbanization equally and significantly contribute to spread of mosquitoes. All these factors add to breeding of Aedes mosquito in any region. Previously a dweller of greenery, this mosquito became domesticated through extensive travel and trade in different areas of Pakistan. Conclusion: First dengue became endemic in Pakistan, then Chikungunya was isolated form Pakistan. Each year resurfacing of dengue infection points towards future danger of spreading of other Aedes borne infections in Pakistan. It is not impossible to say that soon Zika infections will be reported from Pakistan.