In: Insects as Humans’ Frenemies: From Friends to Foes Editor: Istkhar Rao ISBN: 979-8-89530-320-7 © 2025 Nova Science Publishers, Inc. Chapter 9 An Account of “Threat to Humans by Insects: The Culicine Rivalry” Anushree Singha Ray 1 and Kuntal Bhattacharya 2, ∗ 1 Department of Zoology, Michael Madhusudan Memorial College, Durgapur, Paschim Bardhaman, West Bengal, India 2 Department of Zoology, Durgapur Government College, Durgapur, Paschim Bardhaman, West Bengal, India Abstract In our lives, the most worrisome insects are mosquitoes. Over 3000 discovered species of mosquitoes and 770 species of Culex have been documented, which act as potent insect vectors for many dreadful ailments like Japanese encephalitis (JE), West Nile fever, filariasis, etc. Generally, vectors account for 17% of infections and 7 lakh deaths in humans worldwide. The pathogens that are transmitted by the Culex are intensely dependent on the ecosystem, environment, and hosts of the mosquito (upon which species it feeds). There is a chance of infestation by Culex in properties that are near marshes, ponds, or lakes, as these mosquitoes are fascinated by temperate and moist environments because these places are ideal for laying their eggs. These common house mosquitoes prefer to bite at dawn and dusk. It detects the human's bite by body heat and the exhaled CO2. The disease burden is highest in tropical and subtropical areas, where mainly the poorest populations get infected. However, the epidemiological hearsay of various mosquito-borne maladies in assorted parts of Europe proved fascinating evidence that vector-borne diseases are not restricted to tropical and subtropical regions anymore. Among the Culex mosquito-borne diseases, outbreaks of JE, lymphatic filariasis, West Nile fever, and yellow fever claimed a lot of lives and caused chronic suffering, disability, life-long morbidity, disfiguration, and stigmatization. It is known that lymphatic filariasis affects about 100 million people, mainly those with low socio-economic profiles, worldwide every year. Ninety per cent of filarial cases are transmitted by Culex mosquitoes, and the prime responsible vector species are Cx. pipiens, Cx. molestus, Cx. quinquefasciatus, and Cx. plens. Another deadly disease is Japanese encephalitis (JE), or brain fever, caused by flavivirus, which is transmitted throughout Asia via the mosquito vectors Cx vishnui and Cx tritaeniorhynchus. Besides these two species, there are several other Culex species, i.e., Cx. epidesmusanhyrcanus, Cx. bitaeniorhynchus, Cx. whitmorei, Cx. pseudovishnui, Cx. fuscocephala, and Cx. gelidus, responsible for the transmission of this disease. JE also showed yearly deaths of around 13,600 to 20,400 and about 68,000 infections globally. To date, these deadly diseases have no vaccines; therefore, to reduce the disease burden, we have to manage the vector ∗ Corresponding Author’s Email: kbbjoy@gmail.com. Complimentary Copy