Epidemiological trends of Crimean-Congo hemorrhagic fever in South Asia: a systematic review

Crimean-Congo Hemorrhagic Fever is primarily transmitted through ticks or contact with infected animals or individuals. Its prevalence varies globally, with higher incidences observed in Asia and Africa. In South Asia, there are few longitudinal studies on CCHF despite reported outbreaks in countries like Pakistan, Afghanistan, and India. This systematic review aims to synthesize evidence on the epidemiology, clinical presentation, and prevention of Crimean-Congo haemorrhagic fever in South Asia. This systematic review was conducted in accordance with PRISMA 2020 and SWiM guidelines. Literature searches were performed on PubMed, Scopus and Google Scholar (1994–2026), in addition IDSP weekly outbreak reports were searched from the National Centre for Disease Control IDSP website for cases from India. Eligible studies included observational studies, outbreak investigations, and hospital-based reports from South Asian countries reporting human CCHF cases. The review protocol was registered in the PROSPERO database (CRD42023463930). A total of 59 studies from Pakistan, India, and Afghanistan, reporting 4116 suspected cases with 1888 lab-confirmed cases, with 22% case fatality rate among the confirmed cases (India: 49%, Pakistan: 9%, Afghanistan: 28%). Affected individuals had the mean age of 34.4 years, with the highest-risk occupations including butchers and livestock handlers. Frequent clinical manifestations included fever, hemorrhagic features (notably epistaxis), myalgia, headache, abdominal pain, and gastrointestinal symptoms. Laboratory abnormalities frequently included thrombocytopenia, leukopenia, and elevated liver enzymes (AST and ALT). This review on CCHF highlights the importance of identifying high-risk groups like healthcare workers and livestock handlers, understanding seasonal trends and implementing effective surveillance specifically, in Herat Province (Afghanistan), Baluchistan and Khyber Pakhtunkhwa (Pakistan), and the Kutch and Amreli districts of Gujarat (India).