Abstract:
Crimean-Congo haemorrhagic fever (CCHF) is a severe tick-borne viral zoonosis endemic
to parts of Africa, Europe, the Middle East and Central Asia. Human cases are reported
annually in South Africa, with a 25% case fatality rate since the first case was recognized in
1981. We investigated CCHF virus (CCHFV) seroprevalence and risk factors associated
with infection in cattle and humans, and the presence of CCHFV in Hyalomma spp. ticks in
central South Africa in 2017–18. CCHFV IgG seroprevalence was 74.2% (95%CI: 64.2–
82.1%) in 700 cattle and 3.9% (95%CI: 2.6–5.8%) in 541 farm and wildlife workers. No veterinary personnel (117) or abattoir workers (382) were seropositive. The prevalence of
CCHFV RNA was significantly higher in Hyalomma truncatum (1.6%) than in H. rufipes
(0.2%) (P = 0.002). Seroprevalence in cattle increased with age and was greater in animals
on which ticks were found. Seroprevalence in cattle also showed significant geographic variation. Seroprevalence in humans increased with age and was greater in workers who handled livestock for injection and collection of samples. Our findings support previous
evidence of widespread high CCHFV seroprevalence in cattle and show significant occupational exposure amongst farm and wildlife workers. Our seroprevalence estimate suggests
that CCHFV infections are five times more frequent than the 215 confirmed CCHF cases
diagnosed in South Africa in the last four decades (1981–2019). With many cases undiagnosed, the potential seriousness of CCHF in people, and the lack of an effective vaccine or
treatment, there is a need to improve public health awareness, prevention and disease
control.
