Genetic characterization of the M RNA segment of a Balkan Crimean-Congo hemorrhagic fever virus strain

Molecular characterization of small and medium segments of Crimean-Congo hemorrhagic fever virus in Turkey

Aim: The objective was to investigate the genotypic relationship of S and M segments in Crimean-Congo hemorrhagic fever virus (CCHFV) by phylogenetic analysis in 25 patients from seven endemic cities in Turkey. Materials & methods: A total of 25 samples from patients with CCHF were included between 2012 and 2015. Phylogenetic tree analyses were inferred using MEGA version-6.0 and distances were calculated by Kimura’s 2-parameter. Results: Phylogenetic analysis showed that all isolated viruses (n = 25) were in the predicted clades such as clade V- Europe-1 regarding both S and M segments of the CCHFV. Conclusion: Further epidemiological, molecular and phylogenic studies should be performed in both reservoir animals/vectors and humans to determine the incidence of tick-borne infectious disease and to help to develop vaccines for prevention of the disease.

Emerging Tick-Borne Viruses in the Twenty-First Century

Ticks, as a group, are second only to mosquitoes as vectors of pathogens to humans and are the primary vector for pathogens of livestock, companion animals, and wildlife. The role of ticks in the transmission of viruses has been known for over 100 years and yet new pathogenic viruses are still being detected and known viruses are continually spreading to new geographic locations. Partly as a result of their novelty, tick-virus interactions are at an early stage in understanding. For some viruses, even the principal tick-vector is not known. It is likely that tick-borne viruses will continue to emerge and challenge public and veterinary health long into the twenty-first century. However, studies focusing on tick saliva, a critical component of tick feeding, virus transmission, and a target for control of ticks and tick-borne diseases, point toward solutions to emerging viruses. The aim of this review is to describe some currently emerging tick-borne diseases, their causative viruses, and to discuss research on virus-tick interactions. Through focus on this area, future protein targets for intervention and vaccine development may be identified.

Molecular epidemiology of Crimean-Congo hemorrhagic fever virus in Kosovo

Crimean-Congo hemorrhagic fever virus (CCHFV) is a zoonotic agent that causes severe, life-threatening disease, with a case fatality rate of 10–50%. It is the most widespread tick-borne virus in the world, with cases reported in Africa, Asia and Eastern Europe. CCHFV is a genetically diverse virus. Its genetic diversity is often correlated to its geographical origin. Genetic variability of CCHFV was determined within few endemic areas, however limited data is available for Kosovo. Furthermore, there is little information about the spatiotemporal genetic changes of CCHFV in endemic areas. Kosovo is an important endemic area for CCHFV. Cases were reported each year and the case-fatality rate is significantly higher compared to nearby regions. In this study, we wanted to examine the genetic variability of CCHFV obtained directly from CCHF-confirmed patients, hospitalized in Kosovo from 1991 to 2013. We sequenced partial S segment CCHFV nucleotide sequences from 89 patients. Our results show that several viral variants are present in Kosovo and that the genetic diversity is high in relation to the studied area. We also show that variants are mostly uniformly distributed throughout Kosovo and that limited evolutionary changes have occurred in 22 years. Our results also suggest the presence of a new distinct lineage within the European CCHF phylogenetic clade. Our study provide the largest number of CCHFV nucleotide sequences from patients in 22 year span in one endemic area.

Crimean-Congo hemorrhagic fever (CCHF) is an acute, tick-borne disease with a case fatality rate of 10–30%. It is geographically the most widespread tick-borne disease in the world. In recent years there has been an increase of the disease incidence in several countries, mainly in the countries of the Balkan. The disease is also endemic in Kosovo. Since CCHF virus is very genetically diverse we aimed to determine the genetic variability of the virus in Kosovo in the span of 22 years. We obtained the largest number of patient derived nucleotide sequences and found great genetic variability which has been more or less stable during the 22 year period. Our results also suggest that significant changes in viral population occur in different years. We show that ecological factors such as temperature could play a role in the composition of the viral population.

An update on crimean congo hemorrhagic Fever

Crimean Congo hemorrhagic fever (CCHF) is one of the deadly hemorrhagic fevers that are endemic in Africa, Asia, Eastern Europe, and the Middle East. It is a tick-borne zoonotic viral disease caused by CCHF virus of genus Nairovirus (family Bunyaviridae). CCHF not only forms an important public health threat but has a significant effect on the healthcare personnel, especially in resource-poor countries. India was always a potentially endemic area until an outbreak hit parts of Gujarat, taking four lives including the treating medical team. The current review is an attempt to summarize the updated knowledge on the disease particularly in modern era, with special emphasis on nosocomial infections. The knowledge about the disease may help answer certain questions regarding entry of virus in India and future threat to community.

The complete genome analysis of Crimean-Congo hemorrhagic fever virus isolated in Turkey

Crimean-Congo hemorrhagic fever virus (CCHFV) is the causative agent of a tick-borne disease with high mortality rates in humans. The distribution of CCHFV includes over 30 countries in Asia, the Middle East, southeastern Europe, and Africa. It was first recognized in Turkey in 2002, with an increasing number of cases reported between 2002 and 2009. Recent analysis of complete genome sequences of CCHFV isolates has revealed that the genomic plasticity of the virus is surprisingly high for an arthropod-borne virus. We have determined the complete nucleotide and deduced amino acid sequences of strain CCHFV Turkey-Kelkit06 isolated from the blood of a patient in an endemic region of Turkey in 2006. The complete sequence length of the CCHFV Turkey-Kelkit06 strain is 19,186 nt, consisting of a 1673 nt S segment, a 5364 nt M segment, and a 12,149 nt L segment. Based on the analysis of S, M, and L segments, CCHFV Turkey-Kelkit06 clustered in Group V, which represents the Europe/Turkey geographic lineage. Although glycoproteins encoded by the M gene are the most variable part of the CCHFV Turkey-Kelkit06 strain, some functional domains of the glycoproteins are well conserved. Here, we report the complete sequence and genome organization of the CCHFV Turkey-Kelkit06 strain and its phylogenetic relationship to other strains of CCHFV. Collecting data on viral sequences among isolates from CCHF epidemics may provide valuable information regarding the molecular basis of the epidemic potential of the virus.

Towards an understanding of the migration of Crimean-Congo hemorrhagic fever virus

Crimean-Congo haemorrhagic fever (CCHF) is a lethal disease caused by Crimean-Congo hemorrhagic fever virus (CCHFV). It is one of the most widespread medically significant tick-borne pathogens, with a distribution that coincides well with the geographical occurrence of its tick vector, Hyalomma marginatum marginatum. Sporadic outbreaks of CCHF have previously been recognized in Asia, Africa, the Middle East and Europe but, in the 21st century, outbreaks have become more frequent in former Yugoslavia, Turkey and Iran. It has been suggested that CCHFV is a migrating pathogen, but it is not clear to what extent. We have, for the first time, analysed the worldwide migration pattern of CCHFV. Our results showed that Turkey may be a donor in Europe, towards both the east and the west, while the United Arab Emirates acted as a donor in the Middle East, and China was found to be the origin for genotype 2. Finally, we showed that migration of CCHFV was unrestricted between Iran and Pakistan. Considering the distribution and coincidence of the tick vector with CCHFV and CCHF, and the fact that the tick vector is present in western Europe, future outbreaks may extend to include hitherto-naïve areas, suggesting that increased surveillance and geographical mapping of this lethal pathogen are needed.

The complete genome sequence of a Crimean-Congo hemorrhagic fever virus isolated from an endemic region in Kosovo

The Balkan region and Kosovo in particular, is a well-known Crimean-Congo hemorrhagic fever (CCHF) endemic region, with frequent epidemic outbreaks and sporadic cases occurring with a hospitalized case fatality of approximately 30%. Recent analysis of complete genome sequences of diverse CCHF virus strains showed that the genome plasticity of the virus is surprisingly high for an arthropod-borne virus. High levels of nucleotide and amino acid differences, frequent RNA segment reassortment and even RNA recombination have been recently described. This diversity illustrates the need to determine the complete genome sequence of CCHF virus representatives of all geographically distinct endemic areas, particularly in light of the high pathogenicity of the virus and its listing as a potential bioterrorism threat. Here we describe the first complete CCHF virus genome sequence of a virus (strain Kosova Hoti) isolated from a hemorrhagic fever case in the Balkans. This virus strain was isolated from a fatal CCHF case, and passaged only twice on Vero E6 cells prior to sequence analysis. The virus total genome was found to be 19.2 kb in length, consisting of a 1672 nucleotide (nt) S segment, a 5364 nt M segment and a 12150 nt L segment. Phylogenetic analysis of CCHF virus complete genomes placed the Kosova Hoti strain in the Europe/Turkey group, with highest similarity seen with Russian isolates. The virus M segments are the most diverse with up to 31 and 27% differences seen at the nt and amino acid levels, and even 1.9% amino acid difference found between the Kosova Hoti and another strain from Kosovo (9553-01). This suggests that distinct virus strains can coexist in highly endemic areas.

Recent progress in molecular biology of Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a severe hemorrhagic fever in humans with a case fatality rate of up to 50%. A causative agent of CCHF is CCHF virus, which is a tick-borne virus in the family Bunyaviridae, genus Nairovirus. The virus is transmitted to humans through infected tick bites, squashed ticks or from direct contact with viremic animals or humans. Outbreaks of CCHF have been documented in Africa, the Middle East, Eastern Europe and Western Asia where the vector and/or reservoir ticks of Hyalomma spp. are distributed. Recent advances in molecular and biochemical analyses of CCHF virus revealed that the virus encodes larger proteins compared to other genus of Bunyavirus and the processing of viral proteins are complicated. Recent studies also showed that the CCHF viruses are relatively divergent in its genome sequence and the viruses are grouped in seven different clades. In general, these phylogenetic analyses based on sequences of S-RNA and L-RNA segment of CCHF viruses indicate that the seven clades correlate with their geographical location. The phylogenetic topology based on M-RNA segment sequences of CCHF viruses is different from those based on S-RNA and L-RNA segments. These analyses indicate that M-RNA segment reassortment events occur more frequently than those in S- and L-RNA segments.

Crimean-Congo hemorrhagic fever virus: genetic analysis and tick survey in Turkey

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus in the family Bunyaviridae, genus Nairovirus. The virus is transmitted to humans through infected tick bites or from direct contact with viremic animals or humans. In the present study, a total of 1,015 adult ticks were collected from cattle (603 specimens), sheep (17 specimens), and goats (395 specimens) in the Kelkit Valley in Turkey. Four tick species were recognized on the animals in the surveyed region. The most abundant species were Rhipicephalus bursa and Hyalomma marginatum marginatum, at 47.68% (484/1,015) and 46.40% (471/1,015), respectively. Reverse transcriptase PCR was used to recover partial sequences of the CCHFV small (S) genome segment. The presence of CCHFV was determined in 3 of 33 (9.09%) R. bursa pools and in 1 of 31 (3.22%) H. m. marginatum pools. Virus sequences from R. bursa were extremely different from those of the Greek CCHFV strain (U04958) isolated from an R. bursa tick. Phylogenetic analysis indicated that the CCHFV isolates obtained in this study clustered in group 5, whose range encompasses southwestern Russian and Kosovo. This is the first evidence of CCHFV in ticks from Turkey. Even though Hyalomma is the main vector for CCHFV, R. bursa may play a role in CCHFV transmission.

The Complete Genomic Sequence of Strain ROS/HUVLV-100, A Representative Russian Crimean Congo Hemorrhagic Fever Virus Strain

The complete genomic sequence (minus primer-generated ends) of the laboratory-adapted Crimean Congo hemorrhagic fever virus (CCHFV) strain ROS/HUVLV-100, isolated in 2003 from the blood of a deceased female from the Rostov region of southern European Russia, was determined by direct sequencing of overlapping reverse transcription/polymerase chain reaction amplified products. The size of the ROS/HUVLV-100 genome is 19.2 kilobases--individual genome segments are similar in size and sequence features to previously reported "Europe-1" group CCHFV strains. The low-passage ROS/HUVLV-100 strain is the first Russian Crimean Congo hemorrhagic fever virus isolate for which complete sequence information is available, and this work reports the first complete genomic CCHFV sequence determined from a single viral RNA preparation in the same laboratory.

Crimean-Congo haemorrhagic fever

Crimean-Congo haemorrhagic fever (CCHF) is an often fatal viral infection described in about 30 countries, and it has the most extensive geographic distribution of the medically important tickborne viral diseases, closely approximating the known global distribution of Hyalomma spp ticks. Human beings become infected through tick bites, by crushing infected ticks, after contact with a patient with CCHF during the acute phase of infection, or by contact with blood or tissues from viraemic livestock. Clinical features commonly show a dramatic progression characterised by haemorrhage, myalgia, and fever. The levels of liver enzymes, creatinine phosphokinase, and lactate dehydrogenase are raised, and bleeding markers are prolonged. Infection of the endothelium has a major pathogenic role. Besides direct infection of the endothelium, indirect damage by viral factors or virus-mediated host-derived soluble factors that cause endothelial activations and dysfunction are thought to occur. In diagnosis, enzyme-linked immunoassay and real-time reverse transcriptase PCR are used. Early diagnosis is critical for patient therapy and prevention of potential nosocomial infections. Supportive therapy is the most essential part of case management. Recent studies suggest that ribavirin is effective against CCHF, although definitive studies are not available. Health-care workers have a serious risk of infection, particularly during care of patients with haemorrhages from the nose, mouth, gums, vagina, and injection sites. Simple barrier precautions have been reported to be effective.