Congo Virus from Domestic Livestock, African Hedgehog, and Arthropods in Nigeria

Causey, O. R.; Ge, Kemp; Madbouly, M. H.; David‐West, Tam S.

doi:10.4269/ajtmh.1970.19.846

Cited by 80 publications

(48 citation statements)

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“…In previous studies to determine the role of cattle as amplifying hosts of CCHF, Causey and colleagues [12] observed infection of a single H. m. rufipes female that fed on a viraemic calf, while Zarubinsky and colleagues [13] failed to infect adult ticks of three species fed on experimentally infected calves. The results of the present study demonstrate that adult ixodid ticks of several species can acquire CCHF virus infection by feeding on viraemic cattle.…”

Section: Resultsmentioning

confidence: 99%

“…A large number of vertebrate species have been implicated as potential reservoirs. In southern Africa serological surveys indicate that many wild and domestic animals which act as hosts to infected ticks are susceptible to infection [2,9] and experimental studies have shown that cattle, sheep, scrub hares, guinea fowl, and several wild rodent species develop viraemia when infected [10][11][12][13]. In order to assess the role which viraemic vertebrates play as amplifying hosts of the virus and to relate the results of experimental studies to conditions in the field, it is necessary to obtain information on the threshold levels of viraemia necessary for infection of different tick species.…”

Section: Introductionmentioning

confidence: 99%

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Viraemic transmission of Crimean-Congo haemorrhagic fever virus to ticks

et al. 1991

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SUMMARYIn order to determine the way in which vertebrates infected with CrimeanCongo haemorrhagic fever (CCHF) virus and potential ixodid tick vectors interact in nature, immature and adult ticks of several species were fed on viraemic mammals and then assayed for virus content at varying times after feeding. CCHF virus was not isolated from ticks of six species tested after feeding as adults and immature forms on sheep with viraemia of 102 -32 LD 50/ml, nor from larval ticks fed on guinea-pigs and white-tailed rats with viraemia of 1019-27 LD 50/ml. In contrast, virus was isolated from 10 of 152 pools of engorged adult ticks of 5 species that fed on cattle with viraemia of 101'-27 LD 50/ml and from 3 of 137 female ticks after oviposition. Infection was transmitted to larval and nymphal Hyalomma truncatum and H. marginatum rufipes, but not to Rhipicephalus evertsi evertsi, from a scrub hare with viraemia of 1042 LD 50/ml but only nymphal H. truncatum and H. m. rufipes became infected from scrub hares with viraemia of 102 6-2 7 LD 50/ml. Infection was transmitted trans-stadially in H. m. rufipes and H. truncatum infected as nymphae, and adult H. m. rufipes transmitted infection to a sheep. No evidence of transovarial transmission was found in larval progeny of ticks exposed to CCHF virus as adults on sheep and cattle or as immatures on scrub hares.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Viraemic transmission of Crimean-Congo haemorrhagic fever virus to ticks

et al. 1991

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“…Over the next few years, this ''Congo virus'' was also recovered from patient blood specimens, serum samples from domestic goats and cattle and from various species of Hyalomma ticks in Uganda and Nigeria (Causey et al, 1970). Analysis of virus recovered from a recent case in the DRC indicates that the same strain continues to circulate (Grard et al, 2011).…”

Section: Cchf In Africamentioning

confidence: 98%

“…Experimental studies have shown that when soft ticks are experimentally infected with CCHFV, the virus fails to spread to its tissues or persist through its trans-stadial development (Durden et al, 1993;Shepherd et al, 1989b). Although the virus has been isolated from other arthropods, such as biting midges (Causey et al, 1970), this is believed to simply reflect recent feeding on a viremic mammal; there is no evidence that mosquitoes or any arthropod species other than ixodid ticks is a competent vector for CCHFV.…”

Section: Ticks Nairoviruses and Cchfvmentioning

confidence: 99%

“…In contrast to the Drozdov strain, which was recovered from a patient, the virus used as a reference strain by western scientists, IbAr 10200, was isolated from a tick collected from an apparently healthy camel in Nigeria in 1966 (Causey et al, 1970). At that time, human infections had not been reported in the region, but this may simply have reflected a limited surveillance capacity and the sporadic nature of tick-borne diseases, as there is no evidence that African strains of CCHFV are less virulent than those in other regions.…”

Section: Discovery and Naming Of Cchfmentioning

confidence: 99%

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Crimean-Congo hemorrhagic fever: History, epidemiology, pathogenesis, clinical syndrome and genetic diversity

et al. 2013

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Bente, Dennis A.; Forrester, Naomi L.; Watts, Douglas M.; McAuley, Alexander J.; Whitehouse, Chris A.; and Bray, Mike, "CrimeanCongo hemorrhagic fever: History, epidemiology, pathogenesis, clinical syndrome and genetic diversity" (2013 b s t r a c tCrimean-Congo hemorrhagic fever (CCHF) is the most important tick-borne viral disease of humans, causing sporadic cases or outbreaks of severe illness across a huge geographic area, from western China to the Middle East and southeastern Europe and throughout most of Africa. CCHFV is maintained in vertical and horizontal transmission cycles involving ixodid ticks and a variety of wild and domestic vertebrates, which do not show signs of illness. The virus circulates in a number of tick genera, but Hyalomma ticks are the principal source of human infection, probably because both immature and adult forms actively seek hosts for the blood meals required at each stage of maturation. CCHF occurs most frequently among agricultural workers following the bite of an infected tick, and to a lesser extent among slaughterhouse workers exposed to the blood and tissues of infected livestock and medical personnel through contact with the body fluids of infected patients. CCHFV is the most genetically diverse of the arboviruses, with nucleotide sequence differences among isolates ranging from 20% for the viral S segment to 31% for the M segment. Viruses with diverse sequences can be found within the same geographic area, while closely related viruses have been isolated in far distant regions, suggesting that widespread dispersion of CCHFV has occurred at times in the past, possibly by ticks carried on migratory birds or through the international livestock trade. Reassortment among genome segments during co-infection of ticks or vertebrates appears to have played an important role in generating diversity, and represents a potential future source of novel viruses. In this article, we first review current knowledge of CCHFV, summarizing its molecular biology, maintenance and transmission, epidemiology and geographic range. We also include an extensive discussion of CCHFV genetic diversity, including maps of the range of the virus with superimposed phylogenetic trees. We then review the features of CCHF, including the clinical syndrome, diagnosis, treatment, pathogenesis, vaccine development and laboratory animal models of CCHF. The paper ends with a discussion of the possible future geographic range of the virus. For the benefit of researchers, we include a Supplementary Table listing all published reports of CCHF cases and outbreaks in the English-language literature, plus some principal articles in other languages, with total case numbers, case fatality rates and all CCHFV strains on GenBank.

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Ribavirin for treating Crimean Congo haemorrhagic fever

Johnson

Maayan

Mills

et al. 2017

Cochrane Database of Systematic Reviews

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BackgroundCrimean Congo haemorrhagic fever (CCHF) is a tick-borne disease that occurs in parts of Asia, Europe and Africa. Since 2000 the infection has caused epidemics in Turkey, Iran, Russia, Uganda and Pakistan. Good-quality general supportive medical care helps reduce mortality. There is uncertainty and controversy about treating CCHF with the antiviral drug ribavirin. ObjectivesTo assess the effects of ribavirin for treating people with Crimean Congo haemorrhagic fever. Search methodsWe searched the Cochrane Infectious Diseases Group Specialized Register; the Central Register of Controlled Trials (CENTRAL); MEDLINE (PubMed); Embase (OVID); Science Citation Index-Expanded, Social Sciences Citation index, conference proceedings (Web of Science); and CINAHL (EBSCOHost). We also searched the WHO International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for trials in progress. We conducted all searches up to 16 October 2017. We also contacted experts in the field and obtained further studies from these sources. Selection criteriaWe evaluated studies assessing the use of ribavirin in people with suspected or confirmed Crimean Congo haemorrhagic fever. We included randomised control trials (RCTs); non-randomised studies (NRSs) that included more than 10 participants designed as cohort studies with comparators; and case-control studies. Data collection and analysisTwo review authors assessed eligibility, risk of bias, and extracted data. For non-randomized studies we used the ROBINS-I tool to assess risk of bias. The main effects analysis included all studies where we judged the risk of bias to be low, moderate or high. We summarized dichotomous outcomes using risk ratios (RRs) and continuous outcomes using mean differences (MDs), and used meta-analyses where appropriate. We carried out a subsidiary appraisal and analysis of studies with critical risk of bias for the primary outcome, as these are often cited to support using ribavirin.

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Congo Virus from Domestic Livestock, African Hedgehog, and Arthropods in Nigeria

Cited by 80 publications

References 0 publications

Viraemic transmission of Crimean-Congo haemorrhagic fever virus to ticks

Viraemic transmission of Crimean-Congo haemorrhagic fever virus to ticks

Crimean-Congo hemorrhagic fever: History, epidemiology, pathogenesis, clinical syndrome and genetic diversity

Ribavirin for treating Crimean Congo haemorrhagic fever

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