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Ogola EO, Bastos ADS, Slothouwer I, Getugi C, Osalla J, Omoga DCA, Ondifu DO, Sang R, Torto B, Junglen S, Tchouassi DP. Viral diversity and blood-feeding patterns of Afrotropical Culicoides biting midges (Diptera: Ceratopogonidae). Front Microbiol 2024; 14:1325473. [PMID: 38249470 PMCID: PMC10797016 DOI: 10.3389/fmicb.2023.1325473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 12/13/2023] [Indexed: 01/23/2024] Open
Abstract
Introduction Culicoides biting midges (Diptera: Ceratopogonidae) are vectors of arboviral pathogens that primarily affect livestock represented by Schmallenberg virus (SBV), epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV). In Kenya, studies examining the bionomic features of Culicoides including species diversity, blood-feeding habits, and association with viruses are limited. Methods Adult Culicoides were surveyed using CDC light traps in two semi-arid ecologies, Baringo and Kajiado counties, in Kenya. Blood-fed specimens were analysed through polymerase chain reaction (PCR) and sequencing of cytochrome oxidase subunit 1 (cox1) barcoding region. Culicoides pools were screened for virus infection by generic RT-PCR and next-generation sequencing (NGS). Results Analysis of blood-fed specimens confirmed that midges had fed on cattle, goats, sheep, zebra, and birds. Cox1 barcoding of the sampled specimens revealed the presence of known vectors of BTV and epizootic hemorrhagic disease virus (EHDV) including species in the Imicola group (Culicoides imicola) and Schultzei group (C. enderleni, C. kingi, and C. chultzei). Culicoides leucostictus and a cryptic species distantly related to the Imicola group were also identified. Screening of generated pools (11,006 individuals assigned to 333 pools) by generic RT-PCR revealed presence of seven phylogenetically distinct viruses grouping in the genera Goukovirus, Pacuvirus and Orthobunyavirus. The viruses showed an overall minimum infection rate (MIR) of 7.0% (66/333, 95% confidence interval (CI) 5.5-8.9). In addition, full coding sequences of two new iflaviruses, tentatively named Oloisinyai_1 and Oloisinyai_2, were generated by next-generation sequencing (NGS) from individual homogenate of Culicoides pool. Conclusion The results indicate a high genetic diversity of viruses in Kenyan biting midges. Further insights into host-vector-virus interactions as well as investigations on the potential clinical significance of the detected viruses are warranted.
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Affiliation(s)
- Edwin O. Ogola
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Armanda D. S. Bastos
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Inga Slothouwer
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Caroline Getugi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Josephine Osalla
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Dorcus C. A. Omoga
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Dickens O. Ondifu
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Sandra Junglen
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Berlin, Germany
| | - David P. Tchouassi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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Omoga DCA, Tchouassi DP, Venter M, Ogola EO, Osalla J, Kopp A, Slothouwer I, Torto B, Junglen S, Sang R. Transmission Dynamics of Crimean-Congo Haemorrhagic Fever Virus (CCHFV): Evidence of Circulation in Humans, Livestock, and Rodents in Diverse Ecologies in Kenya. Viruses 2023; 15:1891. [PMID: 37766297 PMCID: PMC10535211 DOI: 10.3390/v15091891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023] Open
Abstract
Crimean-Congo haemorrhagic fever virus (CCHFV) is the causative agent of CCHF, a fatal viral haemorrhagic fever disease in humans. The maintenance of CCHFV in the ecosystem remains poorly understood. Certain tick species are considered as vectors and reservoirs of the virus. Diverse animals are suspected as amplifiers, with only scarce knowledge regarding rodents in virus epidemiology. In this study, serum samples from febrile patients, asymptomatic livestock (cattle, donkeys, sheep, and goats), and peridomestic rodents from Baringo (Marigat) and Kajiado (Nguruman) counties within the Kenyan Rift Valley were screened for acute CCHFV infection by RT-PCR and for CCHFV exposure by ELISA. RT-PCR was performed on all livestock samples in pools (5-7/pool by species and site) and in humans and rodents individually. CCHFV seropositivity was significantly higher in livestock (11.9%, 113/951) compared to rodents (6.5%, 6/93) and humans (5.9%, 29/493) (p = 0.001). Among the livestock, seropositivity was the highest in donkeys (31.4%, 16/51), followed by cattle (14.1%, 44/310), sheep (9.8%, 29/295) and goats (8.1%, 24/295). The presence of IgM antibodies against CCHFV was found in febrile patients suggesting acute or recent infection. CCHFV RNA was detected in four pooled sera samples from sheep (1.4%, 4/280) and four rodent tissues (0.83%, 4/480) showing up to 99% pairwise nucleotide identities among each other. Phylogenetic analyses of partial S segment sequences generated from these samples revealed a close relationship of 96-98% nucleotide identity to strains in the CCHFV Africa 3 lineage. The findings of this study suggest active unnoticed circulation of CCHFV in the study area and the involvement of livestock, rodents, and humans in the circulation of CCHFV in Kenya. The detection of CCHF viral RNA and antibodies against CCHFV in rodents suggests that they may participate in the viral transmission cycle.
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Affiliation(s)
- Dorcus C. A. Omoga
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (D.C.A.O.); (D.P.T.); (E.O.O.); (J.O.); (B.T.)
- Zoonotic Arbo and Respiratory Virus Research Program, Centre for Viral Zoonoses, Department of Medical Virology, Faculty of Health, University of Pretoria, Private Bag X 323, Gezina 0031, South Africa;
| | - David P. Tchouassi
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (D.C.A.O.); (D.P.T.); (E.O.O.); (J.O.); (B.T.)
| | - Marietjie Venter
- Zoonotic Arbo and Respiratory Virus Research Program, Centre for Viral Zoonoses, Department of Medical Virology, Faculty of Health, University of Pretoria, Private Bag X 323, Gezina 0031, South Africa;
| | - Edwin O. Ogola
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (D.C.A.O.); (D.P.T.); (E.O.O.); (J.O.); (B.T.)
| | - Josephine Osalla
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (D.C.A.O.); (D.P.T.); (E.O.O.); (J.O.); (B.T.)
| | - Anne Kopp
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany; (A.K.); (I.S.)
| | - Inga Slothouwer
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany; (A.K.); (I.S.)
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (D.C.A.O.); (D.P.T.); (E.O.O.); (J.O.); (B.T.)
| | - Sandra Junglen
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany; (A.K.); (I.S.)
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (D.C.A.O.); (D.P.T.); (E.O.O.); (J.O.); (B.T.)
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Ogola EO, Kopp A, Bastos ADS, Slothouwer I, Omoga DCA, Osalla J, Sang R, Torto B, Junglen S, Tchouassi DP. Phlebovirus diversity in ticks from livestock in arid ecologies in Kenya. Ticks Tick Borne Dis 2023; 14:102087. [PMID: 36459866 DOI: 10.1016/j.ttbdis.2022.102087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 10/11/2022] [Accepted: 11/09/2022] [Indexed: 11/21/2022]
Abstract
Phleboviruses are emerging pathogens of public health importance. However, their association with ticks is poorly described, particularly in Africa. Here, adult ticks infesting cattle, goats and sheep were collected in two dryland pastoralist ecosystems of Kenya (Baringo and Kajiado counties) and were screened for infection with phleboviruses. Ticks mainly belonged to the species Rhipicephalus appendiculatus, Hyalomma impeltatum, and Hyalomma rufipes. A fragment of the RNA-dependent RNA polymerase (RdRp) gene was identified in thirty of 671 tick pools, of which twenty-nine were from livestock sampled in Baringo county. Phylogenetic analyses revealed that twenty-five sequences were falling in three clades within the group of tick-associated phleboviruses. The sequences of the three clades showed nucleotide distances 8%, 19% and 22%, respectively, to previously known viruses suggesting that these sequence fragments may belong to three distinct viruses. Viruses of the group of tick-associated phleboviruses have been found in several countries and continents but so far have not been associated with disease in humans or animals. In addition, five sequences were found to group with the sandfly-associated phleboviruses Bogoria virus, Perkerra virus and Ntepes virus recently detected in the same region. Further studies are needed to investigate the transmission and maintenance cycles of these viruses, as well as to assess their potential to infect vertebrates.
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Affiliation(s)
- Edwin O Ogola
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya; Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Pretoria 0028, South Africa
| | - Anne Kopp
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany
| | - Armanda D S Bastos
- Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Pretoria 0028, South Africa
| | - Inga Slothouwer
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany
| | - Dorcus C A Omoga
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Josephine Osalla
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya; Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Pretoria 0028, South Africa
| | - Sandra Junglen
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany.
| | - David P Tchouassi
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.
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