Crimean-Congo Hemorrhagic Fever Virus In Ticks Research Articles

Crimean-Congo hemorrhagic fever: a growing threat to Europe

Tick-borne infectious diseases are increasing, driven by geographic expansion of ticks. Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus of the family Nairoviridae that poses serious threat to public health. CCHFV can cause severe forms of hemorrhagic fever with high case fatality rates (CFR) (10-40%) and can be transmitted from human to human. Until a few years ago, no cases of CCHF had been reported in western Europe. However, high seropositivity rates in wildlife and detection of multiple strains of CCHFV in ticks in Spain suggest that CCHFV enzootic cycle has been established in some areas of southwestern Europe. As far as CCHFV-associated morbidity and mortality are concerned, there are no approved therapeutic options or US/EU licensed vaccines for treatment. Here we discuss some eco-epidemiological aspects as well as public health and socio-economic impacts associated with CCHFV circulation and outbreaks. We also emphasize that it has become essential to identify key inter-species transmission processes of this group of pathogens, to understand basic molecular mechanisms of their replication, and to define their pathogenic potentials.

Molecular (ticks) and serological (humans) study of Crimean-Congo hemorrhagic fever virus in the Iberian Peninsula, 2013–2015

IntroductionCrimean-Congo hemorrhagic fever (CCHF) is a viral disease, mainly transmitted through tick bite, of great importance in Public Health. In Spain, Crimean-Congo hemorrhagic fever virus (CCHFV) was detected for the first time in 2010 in Hyalomma lusitanicum ticks collected from deer in Cáceres. The aim of this study was to investigate the presence of CCHFV in ticks from Cáceres, and from other Spanish areas, and to evaluate the presence of antibodies against the virus in individuals exposed to tick bites. MethodsA total of 2053 ticks (1333 Hyalomma marginatum, 680 H. lusitanicum and 40 Rhipicephalus bursa) were analyzed using molecular biology techniques (PCR) for CCHFV detection. The determination of specific IgG antibodies against CCHFV in 228 serum samples from humans with regular contact with ticks (at risk of acquiring the infection) was performed by indirect immunofluorescence assay. ResultsThe CCHFV was not amplified in ticks, nor were antibodies against the virus found in the serum samples analyzed. ConclusionThe absence of the CCHFV in the ticks studied and the lack of antibodies against the virus in individuals exposed to tick bites would seem to suggest a low risk of acquisition of human infection by CCHFV in Spain.

Molecular (ticks) and serological (humans) study of Crimean-Congo hemorrhagic fever virus in the Iberian Peninsula, 2013–2015

IntroductionCrimean-Congo hemorrhagic fever (CCHF) is a viral disease, mainly transmitted through tick bite, of great importance in Public Health. In Spain, Crimean-Congo hemorrhagic fever virus (CCHFV) was detected for the first time in 2010 in Hyalomma lusitanicum ticks collected from deer in Cáceres. The aim of this study was to investigate the presence of CCHFV in ticks from Cáceres, and from other Spanish areas, and to evaluate the presence of antibodies against the virus in individuals exposed to tick bites. MethodsA total of 2053 ticks (1333 Hyalomma marginatum, 680 H. lusitanicum and 40 Rhipicephalus bursa) were analyzed using molecular biology techniques (PCR) for CCHFV detection. The determination of specific IgG antibodies against CCHFV in 228 serum samples from humans with regular contact with ticks (at risk of acquiring the infection) was performed by indirect immunofluorescence assay. ResultsThe CCHFV was not amplified in ticks, nor were antibodies against the virus found in the serum samples analyzed. ConclusionThe absence of the CCHFV in the ticks studied and the lack of antibodies against the virus in individuals exposed to tick bites would seem to suggest a low risk of acquisition of human infection by CCHFV in Spain.

Crimean-Congo hemorrhagic fever virus clades V and VI (Europe 1 and 2) in ticks in Kosovo, 2012.

Despite being a small country, Kosovo represents one of the few foci of Crimean-Congo hemorrhagic fever (CCHF) in Europe. The distribution of Kosovar tick vectors and the evolution of CCHF virus in ticks are both as yet unknown. A better description of the extent and the genetic diversity of CCHFV in ticks from endemic settings is essential, in order to be controlled. We investigated the 2012 distribution of Kosovar ticks alongside the prevalence and the phylogeography of tick-derived CCHFV. Hyalomma marginatum dominated in the endemic municipalities with 90.2% versus 24.3% in the non-endemic regions. Of 1,102 tested ticks, 40 (3.6%) were CCHFV-positive, belonging to H. marginatum (29), Rhipicephalus bursa (10), and Ixodes ricinus (1). The virus strains clustered with clade V and VI related sequences. They fell into two lineages: Kosovo I and II. Kosovo I comprised strains recovered exclusively from R. bursa ticks and was closely related to AP92 prototype strain. Kosovo II clustered into Kosovo IIa, including human-derived strains, and IIb including only strains detected in H. marginatum and I. ricinus. Our phylogeographic reconstruction suggests two temporally distinct CCHFV introductions: the most probable location of the most recent common ancestor of Kosovo I lineage was in Greece (63 years ago) and that of lineages IIa-b in Turkey (35 years ago). After each CCHFV introduction into Kosovo, subsequent lineage expansions suggest periods of in situ evolution. The study provides the first insight into the genetic variability and the origin of CCHFV in ticks from Kosovo. Our findings indicate the spreading of CCHFV to non-endemic areas, which underlines the importance of further studies in order to monitor and predict future CCHF outbreaks in Kosovo. The AP92-like strains appear to be more widespread than previously thought and may provide a promising target for experimental studies due to their assumed low pathogenicity.

Reverse Transcription PCR-Based Detection of Crimean-Congo Hemorrhagic Fever Virus Isolated from Ticks of Domestic Ruminants in Kurdistan Province of Iran

Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal viral vector-borne zoonosis which has a mortality rate of up to 30% without treatment in humans. CCHF virus is transmitted to humans by ticks, predominantly from the Hyalomma genus. Following the report of two confirmed and one suspected death due to CCHF virus in Kurdistan province of Iran in 2007, this study was undertaken to determine the fauna of hard ticks on domestic ruminants (cattle, sheep, and goats) and their possible infection with CCHF virus using reverse transcription PCR technique. This is the first detection of CCHF virus in ticks from the Kurdistan province of Iran. Overall, 414 ixodid ticks were collected from two districts in this province. They represented four genera from which 10 separate species were identified. The Hyalomma genus was the most abundant tick genus (70%). It was the only genus shown to be infected with the CCHF virus using RT-PCR technique. The number of ticks positive for CCHF virus was 5 out of 90 (5.6%) adult ticks. The three remaining genera (Haemaphysalis, Rhipicephalus, and Dermacentor) were all negative following molecular survey. Four of the five virally-infected ticks were from cattle mainly in the Sanandaj district. We concluded that CCHF virus is present in the Hyalomma ticks on domestic ruminants (cattle) in Kurdistan province of Iran.