Detection Of Crimean-Congo Haemorrhagic Fever Virus And Rickettsia Spp. In Ticks And Disease Exposure Of Livestock Handlers In The Greater Accra And Upper East Regions Of Ghana
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Date
2022-10
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University of Ghana
Abstract
Ticks are important blood-sucking arthropod vectors. They are known to spread a wide range
of diseases that cause severe and life-threatening illnesses in humans and animals all over the
world through feeding. In population-dense and trade-dominant areas such as the Greater Accra
and Upper East Regions, the risk of zoonotic infections may be on the rise. This study,
therefore, sought to identify the circulating tick species, assess the pathogens they carry and
the risk of exposure of primary animal handlers.
A total of 705 ticks were collected from cattle (n=188) and horses (n=11). Three tick genera
(Hyalomma, Amblyomma and Rhipicephalus) were observed in the study with the predominant
species being Hyalomma rufipes (n=290, 41.13%), followed by Amblyomma variegatum
(n=157, 22.27%) and the least, Rhipicephalus sanguineus (n=1, 0.14%). It was also observed
that the preferred point of attachment of all identified ticks was predominantly the Anal region
(n=469, 68.37%) with the least site being the Abdominal region (n=5, 0.73%) for cattle except
for Horses that had the least site being the chest (n=1, 5.26%).
Out of the 705 tick samples, it was observed that in the Upper East Region, higher percentage
of ticks collected (62.67%) were infected with Rickettsia as compared to ticks from Greater
Accra (42.13%). Similarly, slightly more ticks were infected with Rickettsia africae in the
Upper East Region (91.8%) than Greater Accra (91.38%). In addition, although Amblyomma
variegatum was the second most prevalent species identified, the highest Rickettsia and
Rickettsia africae infection rates were recorded in this species. The highest CCHFV infection
rates were observed in Hyalomma rufipes.
Serology carried out for a total of 120 human sera samples, for Rickettsia using an in-house
ELISA revealed that 27.50% had been exposed to Spotted Fever Group (SFG) and 4.17% to Typhus Group (TG) and none exposed to the Scrub Typhus group (STG). Furthermore,
preliminary analysis for antibodies to CCHFV IgG was detected in 42.5% of the human serum
(n=120) samples pending confirmatory Plaque Reduction Neutralization Test (PRNT).
This study further reports the first whole-genome sequencing of CCHFV in tick species within
Ghana with sequence analysis revealing genotype III (Africa III) may be circulating in the
Upper East Region of Ghana. This suggests the possible importation of the CCHFV virus into
the country through trade and thus puts livestock and humans who may have primary contact
with livestock at risk of infection of these diseases.
Description
MPhil. Applied Parasitology
Keywords
Crimean-Congo, Haemorrhagic Fever, Virus, Rickettsia Spp, Greater Accra, Upper East Regions Of Ghana