An epidemiological investigation of a multisource outbreak of Crimean-Congo hemorrhagic fever in Karachi, from January– 15th September 2016

Abstract

Purpose: In Pakistan Crimean–Congo haemorrhagic fever (CCHF) is an emerging life-threatening viral disease with case fatality rates up to 50%. With the increase in number of CCHF confirmed cases in the Karachi by December 2015, we decided to focus attention on disease in 2016. An epidemiological investigation was conducted in District Karachi to estimate the magnitude and associated risk factors for infection. Methods & Materials: From January- September 2016 an outbreak investigation was conducted. Cases were identified through an active surveillance in health care facilities by using World Health organization recommended case definition. Information was collected by in personal interview with cases/attendant and review of hospital records. Human blood sample was collected for ELISA followed by PCR. Contact tracing was also done for identification of susceptible cases. Data were analyzed using Epiinfo version 7.0. Results: Twenty-five suspected cases were identified by using WHO recommend cases definition out of them 08 were confirmed on IgM followed by PCR. The mean age for confirmed cases was 34.6 years (range: 16-65); all were male. Persons aged 30-39 years were the most severely affected n=5 (62.5%). Overall cases fatality rate (CFR) was n=6 (75%). The most frequent clinical features was fever n=8 (100%) followed by body pain n=7 (87.5%) and hemorrhagic manifestations n=6 (75%). When the cases were evaluated in terms of risk factors, the majority of the cases (n=4; 50%) were engaged in trading of animals. (n=2; 25%) has history of contact with animals. Two cases (25%) were medical doctor had history of operation of CCHF infected patient. Fifty percent (n=4) cases were reported in the month of August. Thirty three close contacts were traced and followed for 14 days no symptomatic evidence of the disease was reported. Conclusion: Failure to implement CCHF preventive measures have contributed to the outbreak with high CFR. Community based health education campaigns were done, and strict compliance of infection control practices were instituted in the hospital. Establishment of prevention and control program on CCHF with efficient surveillance will be helpful for future outbreak.