Crimean-Congo haemorrhagic fever virus screening among African individuals in Spain: Lessons to learn

Background

Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne viral disease. CCHF is an emerging infectious disease given the expanding distribution of its main vector. This study aimed to evaluate the importance of CCHFV infection in migrants from Africa who attended a tertiary health care centre in Spain.

Methodology

A seroepidemiological study was conducted among African patients referred to the University Hospital of Salamanca, Spain. Patients were retrospectively recruited from 2005 to 2023.

Principal findings

We screened 485 serum samples, with a mean (±SD) age of 17 years (±9.9). Among these individuals, 18 were IgG positive and 9 were IgM positive, resulting in an IgG seroprevalence against CCHFV of 3.71 % and an IgM seroprevalence of 1.85 %. Most IgG-positive samples were collected in 2010 (14/316), representing a seroprevalence of 4.43 %. Forty-seven percent of the immigrant participants were from Equatorial Guinea; thus, the IgG seroprevalence among the Equatorial Guinean immigrant population (13/228) was 5.70 %. All patients were negative according to RT‒PCR.

Conclusions

This is the first serosurvey conducted in Spain to suggest possible active circulation of the virus in Africans. Our results suggest the need for more extensive clinical and epidemiological studies in Africans to determine the epidemiology and transmission of CCHFV in Spain and to evaluate the relevance of control measures for clinical interventions in situations with a potential risk of transmission. Although the risk is considered very low in these collectives, clinicians should be alert to the possibility of new CCHF cases, given the high pathogenicity of CCHFV and the risk of transmission.