Detection of Crimean-Congo hemorrhagic fever virus in blood-fed Hyalomma ticks collected from Mauritanian livestock

Abstract

Background Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to the genus Orthonairovirus (Nairovididae) and is a (re)emerging tick-borne pathogen. It is endemic in most parts of Africa, Asia and southern Europe, and can cause severe hemorrhagic symptoms in humans, with high fatality rates (5–30%). Methods Hyalomma ticks were collected from four different livestock herds (cattle and camels) in Mauritania in 2018. The tick species were determined morphologically and confirmed molecularly by using the cytochrome oxidase 1 gene marker. For the detection of CCHFV, ticks were tested individually by one-step multiplex real-time reverse-transcriptase quantitative polymerase chain reaction. The small segment of all positive samples was sequenced to determine the CCHFV genotype. Results In total, 39 of the 1523 ticks (2.56%) collected from 63 cattles and 28 camels tested positive for CCHFV. Three Hyalomma species were identified. Hyalomma rufipes had the largest proportion of positivity (5.67%; 16/282), followed by Hyalomma dromedarii (1.89%; 23/1214). No Hyalomma impeltatum tested positive (0%; 0/21). Positive ticks were found in only six out of 91 host animals. Viral sequence analysis revealed the presence of two different CCHFV lineages (Africa I and Africa III). Conclusions In this study, 2.56% of Hyalomma ticks collected from camels and cattle in Mauritania tested positive for CCHFV. However, the true prevalence of CCHFV in unfed ticks may be lower, as a considerable number of ticks may have been passively infected during blood-feeding by co-feeding ticks or due to viremia of the host. The results indicate the need to track the actual area of circulation of this virus. Graphic Abstract

Molecular and serological evidence of Crimean-Congo hemorrhagic fever orthonairovirus prevalence in livestock and ticks in Cameroon

“…Indeed, Hyalomma marginatum is the most studied and known vector of CCHFV in Europe and Asia where it is responsible of the transovarian and transstadial transmission of the virus, ensuring, therefore, its maintenance in nature ( Spengler et al., 2016 ). In Africa, the virus has been detected on numerous occasions in H. dromedarii, H. truncatum, H. rufipes and H. impeltatum ( Swanepoel et al., 1983 ; Zivcec et al., 2017 ; Chitimia-Dobler et al., 2019 ; Kajihara et al., 2021 ; Schulz et al., 2021 ) but also in non Hyalomma species ( Lule et al., 2022 ). In our study, CCHFV was found in H. truncatum , although at a low infection rate but not in H. rufipes , H. impeltatum , H. nitidum, H. detritum , and H. dromaderii.…”

Investigation Around Cases of Crimean-Congo Hemorrhagic Fever—Mauritania, 2022

“…Between February and May 2022, 8 patients were admitted to Centre Hospitalier de Kiffa (Kiffa department/Assaba region), Hôpital Hamed (Boutilimit department/Trarza region), Centre Hospitalier Cheikh Zeid, Centre Hospitalier National de Nouakchott, or Hôpital de l’Amitié (Nouakchott) with an initial clinical diagnosis of CCHF. This period of the year is characterized by a hot, dry season and transhumance of livestock, which favors the spread of ticks [ 11 , 14 ]. The study population of the present study was individuals who were potentially in contact with these 8 patients suspected to be infected with CCHFV.…”

Systematic Review on Crimean–Congo Hemorrhagic Fever Enzootic Cycle and Factors Favoring Virus Transmission: Special Focus on France, an Apparently Free-Disease Area in Europe

“…Several studies conducted in Africa and Asia have shown that CCHF seroprevalence significantly increases with the animal age, either in cattle, small ruminants, and camels (33,35,(87)(88)(89)(90)(91)(92)(93)(94)(95)(96)(97). This correlation was mainly attributed to an increasing probability of an animal to be exposed to infected tick vectors, contract CCHFV, and develop an immune response in relation with increasing age (33).…”

“…In Sudan, when assessing age as a risk factor for cattle CCHFV seroprevalence, the authors showed that calves started to get infected after the age of 2 years, as this was when animals were released to pasture and therefore became exposed to infected ticks and subsequently to CCHFV infection ( 35 , 89 ). In Mauritania, this hypothesis of overexposure in older animals has been also proposed to explain an apparent higher seroprevalence in camels than in cattle or small ruminants, as camels are bred for longer periods of time ( 95 ). Although we agree that the age effect may be a confounding factor with animal species, most ticks present host preferences that could result in differential infestation rates according to the vertebrate species.…”