Kochi: In Ernakulam District' Kochi city, Culex mosquito density ranges from 50 mosquitoes to 70 mosquitoes per hour, according to recent health department data from their filariasis monitoring program. A man-hour density (MHD) above 10 mosquitoes is considered concerning. According to health officials, while the density was below 40 MHD during October-November's northeast monsoon, it could reach 83 MHD by January 2025 due to reduced rainfall and increased humidity.According to a Times of India report, Kochi's climate, with temperatures around 30 degrees Celsius, provides ideal breeding conditions for Culex mosquitoes. These nocturnal mosquitoes, active after 8 PM, rest in dark rooms or on dark clothes during the daytime. The report noted that they are responsible for a significant burden of zoonotic virus transmission globally. They transmit medically significant diseases such as encephalitis, filariasis, and the West Nile virus.A senior health official involved in monitoring said, "Ernakulam likely has the highest Culex density compared to other districts. They breed in open drains, wastewater pits, and septic tanks. Covering these sources is crucial. There should be no room for ventilation as the Culex mosquitoes can enter through tiny gaps and give sleepless nights to people," as quoted by TOI.Officials have further emphasised community-wide prevention, as Culex mosquitoes can fly up to 2 kilometers. A health officer warned that individual household efforts won't suffice. The health officer said, "All residents must cover potential breeding sources, while local bodies should cover drains and conduct regular spraying. With Kochi's many open drains and inadequate premises maintenance, the situation may worsen," as quoted by TOI.The department has cautioned against excessive chemical use in drains, as it kills natural larvae-eating organisms. The official also noted that while lymphatic filariasis has no cure, medication can prevent its spread. The official said, "Ernakulam has no indigenous cases; most active cases are among migrants, with continuing positive blood smear reports in migrant workers," as quoted by TOI. The district currently has 555 active filaria cases, the report added.