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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
A. Schulz; Y. Barry; F. Stoek; M. J. Pickin; A. Ba; L. Chitimia-Dobler; M. L. Haki; B. A. Doumbia; A. Eisenbarth; A. Diambar; M. Y. Bah; M. Eiden; M. H. Groschup. Detection of Crimean-Congo hemorrhagic fever virus in blood-fed Hyalomma ticks collected from Mauritanian livestock. Parasites & Vectors 2021, 14, 1 -10.
AMA StyleA. Schulz, Y. Barry, F. Stoek, M. J. Pickin, A. Ba, L. Chitimia-Dobler, M. L. Haki, B. A. Doumbia, A. Eisenbarth, A. Diambar, M. Y. Bah, M. Eiden, M. H. Groschup. Detection of Crimean-Congo hemorrhagic fever virus in blood-fed Hyalomma ticks collected from Mauritanian livestock. Parasites & Vectors. 2021; 14 (1):1-10.
Chicago/Turabian StyleA. Schulz; Y. Barry; F. Stoek; M. J. Pickin; A. Ba; L. Chitimia-Dobler; M. L. Haki; B. A. Doumbia; A. Eisenbarth; A. Diambar; M. Y. Bah; M. Eiden; M. H. Groschup. 2021. "Detection of Crimean-Congo hemorrhagic fever virus in blood-fed Hyalomma ticks collected from Mauritanian livestock." Parasites & Vectors 14, no. 1: 1-10.
Rift Valley fever phlebovirus (RVFV) is a zoonotic arthropod-borne virus, which has led to devastating epidemics in African countries and on the Arabian Peninsula. Results of in-vivo, in-vitro and field studies suggested that amphibians and reptiles may play a role as reservoir hosts of RVFV, promoting its maintenance during inter-epidemic periods. To elucidate this hypothesis, we examined two newly established reptile-derived cell lines (Egyptian cobra and Chinese pond turtle) and five previously generated reptile- and amphibian-derived cell lines for their replicative capacity for three low- and high-pathogenic RVFV strains. At different time points after infection, viral loads (TCID50), genome loads and the presence of intracellular viral antigen (immunofluorescence) were assessed. Additionally, the influence of temperatures on the replication was examined. Except for one cell line (read-eared slider), all seven cell lines were infected by all three RVFV strains. Two different terrapin-derived cell lines (Common box turtle, Chinese pond turtle) were highly susceptible. A temperature-dependent replication of RVFV was detected for both amphibian and reptile cells. In conclusion, the results of this study indicate the general permissiveness of amphibian and reptile cell lines to RVFV and propose a potential involvement of terrapins in the virus ecology.
Melanie Rissmann; Matthias Lenk; Franziska Stoek; Claudia Szentiks; Martin Eiden; Martin Groschup. Replication of Rift Valley Fever Virus in Amphibian and Reptile-Derived Cell Lines. Pathogens 2021, 10, 681 .
AMA StyleMelanie Rissmann, Matthias Lenk, Franziska Stoek, Claudia Szentiks, Martin Eiden, Martin Groschup. Replication of Rift Valley Fever Virus in Amphibian and Reptile-Derived Cell Lines. Pathogens. 2021; 10 (6):681.
Chicago/Turabian StyleMelanie Rissmann; Matthias Lenk; Franziska Stoek; Claudia Szentiks; Martin Eiden; Martin Groschup. 2021. "Replication of Rift Valley Fever Virus in Amphibian and Reptile-Derived Cell Lines." Pathogens 10, no. 6: 681.
Rift Valley fever (RVF) is a major viral zoonosis transmitted by mosquitoes. The virus is endemic in most parts of sub-Saharan Africa and can affect humans, livestock, and wild ungulates. Knowledge of the biology of vectors of Rift Valley fever virus (RVFV) is essential for the establishment of effective control measures of the disease. The objective of this study was to determine the species diversity and relative abundance of potential RVFV vectors in the North Region of Cameroon. Adult mosquitoes were trapped during the wet and dry seasons from December 2017 to January 2019 with “EVS Light” traps with CO2 baits placed at selected sites. The captured mosquitoes were identified using dichotomous keys according to standard procedures. The abundance was calculated with regard to site, zone, and collection season. A total of 27,851 mosquitoes belonging to four genera (Aedes, Anopheles, Mansonia, and Culex) and comprising 31 species were caught (including 22 secondary vectors (98.05%) and nine primary vectors (1.94%). The total number of mosquitoes varied significantly depending on the locality (p-value < 0.001). The average number of mosquitoes collected per trap night was significantly higher in irrigated areas (p-value < 0.001), compared to urban and non-irrigated areas. The study revealed the presence of potential primary and secondary vectors of RVFV with varying abundance and diversity according to locality and ecological site in the North Region of Cameroon. The results showed that the genus Mansonia with the species Ma. uniformis and Ma. africana formed the dominant taxon (52.33%), followed by the genera Culex (45.04%) and Anopheles (2.61%). The need for molecular analysis (PCR) tests for RVFV RNA research and viral isolation methods on these vectors to determine their role in the epidemiology and control of RVF cannot be overemphasized.
Poueme Namegni Rodrigue Simonet; Njan-Nloga Alexandre Michel; Wade Abel; Eisenbarth Albert; Groschup Martin Hermann; Stoek Franziska. Diversity and Abundance of Potential Vectors of Rift Valley Fever Virus in the North Region of Cameroon. Insects 2020, 11, 814 .
AMA StylePoueme Namegni Rodrigue Simonet, Njan-Nloga Alexandre Michel, Wade Abel, Eisenbarth Albert, Groschup Martin Hermann, Stoek Franziska. Diversity and Abundance of Potential Vectors of Rift Valley Fever Virus in the North Region of Cameroon. Insects. 2020; 11 (11):814.
Chicago/Turabian StylePoueme Namegni Rodrigue Simonet; Njan-Nloga Alexandre Michel; Wade Abel; Eisenbarth Albert; Groschup Martin Hermann; Stoek Franziska. 2020. "Diversity and Abundance of Potential Vectors of Rift Valley Fever Virus in the North Region of Cameroon." Insects 11, no. 11: 814.
Rift Valley fever phlebovirus (RVFV) is an arthropod-borne zoonotic pathogen, which is endemic in Africa, causing large epidemics, characterized by severe diseases in ruminants but also in humans. As in vitro and field investigations proposed amphibians and reptiles to potentially play a role in the enzootic amplification of the virus, we experimentally infected African common toads and common agamas with two RVFV strains. Lymph or sera, as well as oral, cutaneous and anal swabs were collected from the challenged animals to investigate seroconversion, viremia and virus shedding. Furthermore, groups of animals were euthanized 3, 10 and 21 days post-infection (dpi) to examine viral loads in different tissues during the infection. Our data show for the first time that toads are refractory to RVFV infection, showing neither seroconversion, viremia, shedding nor tissue manifestation. In contrast, all agamas challenged with the RVFV strain ZH501 carried virus genomes in the spleens at 3 dpi, but the animals displayed neither viremia nor virus shedding. In conclusion, the results of this study indicate that amphibians are not susceptible and reptiles are only susceptible to a low extent to RVFV, indicating that both species play, if at all, rather a subordinate role in the RVF virus ecology.
Melanie Rissmann; Nils Kley; Reiner Ulrich; Franziska Stoek; Anne Balkema-Buschmann; Martin Eiden; Martin H. Groschup. Competency of Amphibians and Reptiles and Their Potential Role as Reservoir Hosts for Rift Valley Fever Virus. Viruses 2020, 12, 1206 .
AMA StyleMelanie Rissmann, Nils Kley, Reiner Ulrich, Franziska Stoek, Anne Balkema-Buschmann, Martin Eiden, Martin H. Groschup. Competency of Amphibians and Reptiles and Their Potential Role as Reservoir Hosts for Rift Valley Fever Virus. Viruses. 2020; 12 (11):1206.
Chicago/Turabian StyleMelanie Rissmann; Nils Kley; Reiner Ulrich; Franziska Stoek; Anne Balkema-Buschmann; Martin Eiden; Martin H. Groschup. 2020. "Competency of Amphibians and Reptiles and Their Potential Role as Reservoir Hosts for Rift Valley Fever Virus." Viruses 12, no. 11: 1206.