Chikungunya's return amidst 2024 dengue season: Implications for future outbreaks in Bangladesh

Chikungunya, an arboviral disease transmitted by Aedes mosquitoes, shares clinical similarities with dengue, but is distinguished by prolonged joint pain. Following a major outbreak in Bangladesh in 2017, chikungunya nearly vanished from its territory. The study participants were recruited prospectively following specific inclusion criteria and obtained written informed consent. Out of 1280 febrile individuals screened, 569 met the criteria of fever onset within 2-5 days, accompanied by symptoms such as headache, myalgia, bone and joint pain, rash, nausea, vomiting, or diarrhea. Of these, 474 underwent real-time RT-PCR testing. Among the samples tested, 213 were PCR-positive for at least one arbovirus. Chikungunya cases totaled 55, including 7 coinfections (6 with DENV, and the first documented CHIKV-ZIKV coinfection in Bangladesh). No infections were reported from January to August, with a peak in October and November. Most CHIKV infections (72.7%) had moderate to high viral loads, with common symptoms of joint pain, myalgia, and headaches. The resurgence of Chikungunya in late 2024 underscores the potential for a major outbreak in 2025, necessitating proactive measures to mitigate public health impact and ensure a robust response to this re-emerging threat.