Microbiological perspectives on Crimean-Congo hemorrhagic fever: Seroprevalence and viral pathogenesis in Iraq.

BACKGROUND

Crimean-Congo hemorrhagic fever (CCHF) is a serious tick-borne zoonotic disease that is caused by CCHFV and has up to 40 % case fatality rates. Hyalomma ticks and livestock such as cattle, goats and sheep serve as amplifying hosts between which the virus circulates. Recent epidemiological and clinical studies also highlight the importance of integrated epidemiological and clinical studies in Iraq. This paper evaluated CCHFV seroprevalence in human beings, domestic animals and ticks in Iraq and clinical and hematological and biochemical abnormalities in human cases.

METHODS

A cross-sectional study was conducted from January 2021 to December 2022 across ten Iraqi governorates, including 4339 livestock and 150 laboratory-confirmed human cases. Adult ticks were collected from 188 farms and morphologically identified. Human and livestock sera were tested for CCHFV-specific IgG using ELISA, and tick homogenates were screened for viral antigen. Hematological and biochemical parameters in human cases were analyzed with automated methods. Prevalence estimates, chi-square tests, and logistic regression identified predictors of laboratory abnormalities and mortality.

RESULTS

A survey of 4339 livestock in ten Iraqi governorates showed 6.4 % seroprevalence, highest in cattle and in hybrid, female, grazing animals, peaking in spring and autumn. Hyalomma anatolicum was the predominant tick species (78.4 %) and had a CCHFV antigen positivity rate of 6.1 %. Among 150 human cases, 12 % mortality was linked to severe hepatic injury, coagulopathy, metabolic abnormalities, and age over 60, with early care improving outcomes and recovery rates improved significantly.

CONCLUSIONS

The maintenance of CCHF in Iraq occurs by a cattle-H. anatolicum cycle and causes severe multi-organ involvement in humans. The effective mitigation requires a One Health approach integrating livestock surveillance, controlling vectors, and early clinical management guided with prognostic markers.