Tick Fever Virus Research Articles

Circulation of Crimean-Congo haemorrhagic fever virus in ticks in Middle Guinea-Republic of Guinea

Circulation of Crimean-Congo haemorrhagic fever virus in ticks in Middle Guinea-Republic of Guinea

Circulation of Crimean-Congo Haemorrhagic Fever Virus in Ticks in Upper Guinea-Republic of Guinea

The aim of this study was to map the distribution of agents carrying the Crimean-Congo haemorrhagic fever virus (arbovirus-tica) in the natural region of Upper Guinea. The prefectures of Kankan, Dabola and Faranah were used as collection areas. Random sampling of different types of animals was used to collect the biomaterial. Two types of analysis methods (RT-PCR and ELISA) were used. Out of a total of 578 ticks collected and divided into 254 pools, the genus Amblyomma was the most frequently encountered with 83 tick pools. Molecular analysis (RT-PCR) for the detection of virus RNA revealed 2 positive cases (0.8%). Direct enzyme-linked immunosorbent assays (ELISA) for the detection of Ag yielded only one positive case (0.4%). We found that the species Rhipicephalus geigyi was the main vector and reservoir of the pathogen in Upper Guinea.

Crimean Congo Hemorrhagic Fever Virus in Ticks Isolated from Ruminants in Jahrom, Fars Province, Southern Iran

Background:Crimean Congo Hemorrhagic Fever (CCHF) is an emerging tick-borne viral zoonotic disease that is endemic in Iran. The CCHF virus is spread by an RNA virus of the genus Orthonairovirus , the family Nairoviridae. CCHF has been identified as the most frequent viral hemorrhagic fever in Iran. The route of CCHF transmission to humans is through infected tick bites, contact with infected livestock, infected blood or tissues of humans. Objectives: The aim of this study was to investigate the infection of livestocks with different species of ticks and also to determine the presence of CCHF virus in the ticks in Jahrom township. Methods:A total of 200 ticks were collected from Jahrom township, Fars Province, Southern Iran. To detect virus in infected ticks, total RNA was extracted using the RNeasy Mini Kit Qiagen and subjected to reverse transcriptase-polymerase chain reaction. Results:Of all the ticks tested, twelve (6%) were positive for the virus, 124 (62%) belonged to the species Rhipicephalus sanguineus, 37 (18.5%) belonged to Hyalomma anatolicum, 23 (11.5%) belonged to Hyalomma marginatus, 7 (3.5%) belonged to Hyalomma asiaticum, 4 (2%) belonged to Hyalomma dromedarii, and 5 (2.5%) belonged to Rhipicephalus bursa. Of the 200 ticks collected in the area, 117 (58.5%) were male and 83 (41.5%) were female. Conclusion:In this study, for the first time, we analyzed tick samples collected from Jahrom township for the presence of CCHF virus. The findings of our study might be valuable for designing preventive measures regarding CCHF in Fars province, although further studies are required.

Serologic and molecular evidence for circulation of Crimean-Congo hemorrhagic fever virus in ticks and cattle in Bosnia and Herzegovina

Crimean-Congo haemorrhagic fever virus is a tick-borne zoonotic agent of the genus Orthonairovirus, and the causal agent of Crimean-Congo haemorrhagic fever in humans. The study is aimed at investigating the presence of CCHFV RNA in ticks and cattle in Bosnia and Herzegovina (B&H), as well as the exposure of cattle to CCHFV in this country. Only one pool of three male Hyalomma marginatum ticks tested positive for viral RNA (3/760, 0.39%). No viral RNA was detected in 206 bovine blood samples using real-time reverse-transcriptase PCR (RT-qPCR). The overall seroprevalence of CCHFV in the cattle population was estimated as 14.97% (72/481). The results indicate the presence and the established circulation of CCHFV in B&H. Considering the endemic character of CCHFV in the Balkans as well as our results, the possibility that CCHFV is endemic in the territory of Bosnia and Herzegovina is considered to be very high.

Lack of Evidence for Crimean–Congo Hemorrhagic Fever Virus in Ticks Collected from Animals, Corsica, France

In Corsica, France, 9.1% of livestock serum samples collected during 2014–2016 were found to have antibodies against Crimean–Congo hemorrhagic fever virus (CCHFV), an emerging tickborne zoonotic disease. We tested 8,051 ticks for CCHFV RNA and Nairovirus RNA. The results indicate that Corsica is not a hotspot for CCHFV.

Crimean-Congo hemorrhagic fever virus in ticks collected from imported camels in Egypt

Crimean-Congo hemorrhagic fever (CCHF) is one of the utmost broadly distributed tick-borne viruses, with an infection resulting in a fatality rate of up to 30%. During this study period, 25,000 hard adult ticks of Hyalomma species were collected from freshly slaughtered imported camels to determine the presence of Crimean-Congo hemorrhagic fever virus (CCHFV) and genetic lineage of the virus. Ticks were pooled and analyzed for the existence of CCHFV using nested RT- PCR and real-time reverse transcription PCR; the genome was detected in 18 (1.44%) tick pools. Partial genome sequences reveal an adjacent relationship with strains from South Africa to Namibia, Nigeria, Sudan, Senegal, and Mauritania, corresponding to the Africa I and III genotypes. This study indicates the presence of CCHFV in Egypt and illustrates the potential for tick-borne dissemination of the virus. Further studies focused on not only tick samples, but also human samples are epidemiologically valuable to obtain exact data in the region.

Detection of Crimean-Congo hemorrhagic fever virus in ticks collected from South Russia

Crimean-Congo hemorrhagic fever (CCHF) has a central role among tick-borne infections in southern Russia. Multiple cases of disease are recorded annually in most regions with the СCHF foci; moreover, an expansion of the geographic range of the disease has been noted. Since 1999, more than 2300 people have fallen ill in Russia. Ticks are the main vectors and reservoirs of the Crimean-Congo hemorrhagic fever virus (CCHFV). As it is currently known, CCHFV has been detected in ticks of 33 species. In the period 2012–2019 in the south of the European part of Russia, more than 38,000 ticks of 14 species of the genera Hyalomma, Rhipicephalus, Dermacentor, Haemaphysalis and Ixodes were tested for the presence of CCHFV. Among 4,188 tick pools studied, the virus was detected in 252 (6%). The main vector, as expected, is H. marginatum (81% of positive pools). The same species is the most numerous among the studied ticks (66%). Apart from H. marginatum, the virus was detected in the following species: H. scupense, R. rossicus, R. turanicus, R. bursa, R. annulatus, D. marginatus, Haem. punctata and Ixodes ricinus. Most of the positive results were obtained from ticks collected from vertebrate hosts. As for H. marginatum, R. rossicus, D. marginatus, and Haem. punctata, the virus was detected in questing unfed specimens collected from vegetation and soil surface, which indicates the participation of these ticks in the circulation of the virus.

Serologic and molecular evidence for circulation of Crimean-Congo hemorrhagic fever virus in ticks and cattle in Zambia.

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne zoonosis with a high case fatality rate in humans. Although the disease is widely found in Africa, Europe, and Asia, the distribution and genetic diversity of CCHF virus (CCHFV) are poorly understood in African countries. To assess the risks of CCHF in Zambia, where CCHF has never been reported, epidemiologic studies in cattle and ticks were conducted. Through an indirect immunofluorescence assay, CCHFV nucleoprotein-specific serum IgG was detected in 8.4% (88/1,047) of cattle. Among 290 Hyalomma ticks, the principal vector of CCHFV, the viral genome was detected in 11 ticks. Phylogenetic analyses of the CCHFV S and M genome segments revealed that one of the detected viruses was a genetic reassortant between African and Asian strains. This study provides compelling evidence for the presence of CCHFV in Zambia and its transmission to vertebrate hosts.

Prevalence and phylogenetic analysis of Crimean-Congo hemorrhagic fever virus in ticks collected from Punjab province of Pakistan

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne zoonotic disease of human that caused by CCHF virus. To study the epidemiological distribution of CCHFV, 2183 tick samples were collected from sheep, goats, cattle and buffalo of different livestock farms of ten districts of Punjab province of Pakistan. Detection of CCHFV was done using enzyme link immunosorbent assay (ELISA) after proper identification of tick samples. The partial S-segment of CCHFV from ELISA positive tick samples was amplified by PCR and sequenced to determine the genotype of CCHFV. Out of2183 collected tick samples, 1913 ticks belonged to 5 species of genus Hyalomma as H. antolicum (48%), H. marginatum (30.2%), H. rufipes (10.82%), H. impressum (5.43%) and H. dromedarii (5.27%). While 270 ticks belonged to 3 species of genus Rhipicephalus as R. microplus (44.8%), R. sanguineus (32.22%) and R. turanicus (24.8%). The overall antigenic prevalence of CCHFV was found to be 12.13% in collected tick samples and 21 tick pools were sequenced for partial S-segment of CCHFV. All of the 21 tick pools were clustered in genotype IV (Asia-1). The highest prevalence of CCHFV was found in district Chakwal (24.13%) followed by Mianwali (23.68%), Rawalpindi (23.07%), Attock (20.0%), Rajanpur (10.52%) and Lahore (8.33%). In positive tick pools, the highest prevalence of CCHFV antigen was found in H. antolicum (39.6%) followed by H. marginatum (30.18%), H. rufipes (13.2%), H. impressum (3.77%), H. dromedarii (1.88%), R. microplus (5.66%) and R. sanguineus (5.66%). The current study confirms the presence of CCHFV in the ticks population of Punjab. The CCHF virus present in Punjab belongs to Asia-1 genotype. It is important to control the tick infestation of the animals present in these areas. So that the transmission cycle of CCHF can be inhibited.

Widespread Detection of Multiple Strains of Crimean-Congo Hemorrhagic Fever Virus in Ticks, Spain.

Human cases of Crimean-Congo hemorrhagic fever (CCHF) were first detected in Spain in 2016. National human and animal health authorities organized a large, multidisciplinary study focusing on ticks as sentinels to determine the nationwide distribution of ticks with CCHF virus. Ticks were collected from animals and vegetation, samples pooled (12,584 ticks; 4,556 pools), and molecular methods used to look for the virus. We detected the virus in 135 pools from most of the regions studied, indicating that it is widespread in Spain. We found sequences of CCHF virus genotypes I, III, and IV in the tick species collected, most commonly in Hyalomma lusitanicum, suggesting this tick has a prominent role in the virus’s natural cycle. The red deer (Cervus elaphus) was the host that most frequently yielded positive ticks. Our study highlights the need for larger studies in Spain to ascertain the complete risk to public health.

Serosurvey of Crimean-Congo Haemorrhagic Fever Virus (CCHFV) in Cattle in Livestock Areas of Côte d'Ivoire, West Africa

Background: Crimean-Congo haemorrhagic fever virus (CCHFV) is an arbovirus transmitted by Ixodid ticks and causes a highly pathogenic disease called Crimean-Congo haemorrhagic fever with a mortality rate of up to 50% in humans.
 Methods: From January to December 2019, tick and blood samples were taken from seven cattle farms located in the towns of Korhogo, Bondoukou, Man and Bouaflé. In each of the farms, samples were taken from twenty cattle. These tick and blood samples were sent to the national reference laboratory of the Department of Epidemic Viruses of the Pasteur Institute of Côte d'Ivoire for diagnosis of CCHFV as part of the surveillance of haemorrhagic fever viruses in Côte d'Ivoire. Molecular detection of the Crimean-Congo haemorrhagic fevervirus in ticks was performed by real-time PCR. For the serological analysis, the ELISA was used for the detection of antibodies to CCHFV (IgM and IgG).
 Results: The study allowed the identification of 411 ticks divided into three genera Amblyomma, Hyalomma and Rhipicephalus. The predominant species were Rhipicephalus (Boophilus) microplus with (47.4%) and Amblyomma variegatum with (42.8%). No ticks gave positive results for the research of the CCHFV.Serological analysis showed that all 140 blood samples were IgM negative and 53.57% were IgG positive. Cattle from Bouaflé (90%) and Korhogo (70%) showed a higher seroprevalence than cattle from other regions. There was no significant difference in seropositivity between female bovines (54.1%) and male bovines (52.5%) (P>0.05). There is an association between age and anti-CCHF IgG positivity (P≤0.05), as cattle less than 3 years old (59.3%) showed a higher seroprevalence.
 Conclusion: CCHFV serological tests have been detected in cattle, one of the livestock known to play a role in the amplification of CCHFV. Our results demonstrate that the prevalence of CCHFV is high in livestock areas of Côte d'Ivoire and suggest that surveillance for CCHFV should be established.

A Survey of Crimean-Congo Hemorrhagic Fever Virus in Ticks of Shahr-e Ray, Iran, 2016-2017

A Survey of Crimean-Congo Hemorrhagic Fever Virus in Ticks of Shahr-e Ray, Iran, 2016-2017

Crimean-Congo haemorrhagic fever virus in ticks collected from livestock in Balochistan, Pakistan.

Crimean-Congo haemorrhagic fever virus (CCHFV) is a tick-borne zoonotic pathogen. It causes a fatal haemorrhagic disease in humans. Hard ticks, in particular Hyalomma spp., are considered to function as reservoir as well as vector for CCHFV. A cross-sectional study was conducted in the province of Balochistan, Pakistan, from September to November 2017. Ticks were collected from cattle, sheep and goats in livestock farms. The ticks were morphologically identified, followed by confirmation with molecular methods (PCR and sequencing). Furthermore, ticks were examined for CCHFV genomes (S segment) by a one-step multiplex real-time RT-qPCR and positive samples were sequenced to determine the CCHFV genotype. In total, 525 of 529 livestock infesting adult ticks belonged to the genus Hyalomma, and 4 ticks to the genus Rhipicephalus (R.microplus 3×, R.turanicus 1×). In the genus Hyalomma, H.marginatum (28%), H.excavatum (26%), H.dromedarii (22%), H.anatolicum (16%) and H.scupense (8%) ticks were identified. Tick infestations were as follows: sheep 58%, goats 28% and cattle 14%. Four per cent (20/525) of ticks were CCHFV genome-positive, and all genomes clustered in CCHFV genotype Asia 1. Among CCHFV-positive ticks, 75% (15/20) were female and 25% (5/20) male. CCHFV genomes were most frequently detected in H.marginatum (30%, 6/20), followed by H.dromedarii (25%, 5/20), H.excavatum (20%, 4/20), H.anatolicum (20%, 4/20) and H.scupense (5%, 1/20). All CCHFV-positive ticks were found on sheep. The largest number of CCHFV-positive ticks were detected in the district of Kalat (60%, 12/20), followed by the districts of Quetta (30%, 6/20) and Killa Abdullah (10%, 2/20). This study confirms the circulation of CCHFV in ticks in Balochistan, south-western Pakistan. It is imperative to take effective tick control measures in this area, especially to control livestock tick infestations to prevent CCHF infections in humans.

Prevalence and Phylogenetic Analysis of Crimean-Congo Hemorrhagic Fever Virus in Ticks from Different Ecosystems in Xinjiang, China.

The Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the genus Orthonairovirus and family Nairoviridae, is transmitted by ticks and causes severe hemorrhagic disease in humans. To study the epidemiology of CCHFV in different ecosystems in Xinjiang, China, a total of 58,932 ticks were collected from Tarim Basin, Junggar Basin, Tianshan Mountain, and Altai Mountain from 2014 to 2017. Hyalomma asiaticum asiaticum was the dominant tick species in Tarim and Junggar basins, whereas Dermacentor nuttalli and Hyalomma detritum were found in Tianshan Mountain and Altai Mountain, respectively. Reverse transcription-polymerase chain reaction of the CCHFV small (S) genome segment was used for the molecular detection. The CCHFV-positive percentage was 5.26%, 6.85%, 1.94%, and 5.56% in Tarim Basin, Junggar Basin, Tianshan Mountain, and Altai Mountain, respectively. Sequences of the S segment were used for phylogenetic analysis and the results showed that the newly identified CCHFV strains belonged to two clades. Our study confirms that H. asiaticum asiaticum is the major vector of CCHFV in desert habitats which is consistent with previous studies, and also suggests that H.detritum and D. nuttalli are emerging vectors for CCHFV in Xinjiang. Moreover, this study reports the presence of CCHFV in the mountain habitat of Xinjiang for the first time, suggesting that future surveillance of CCHFV should also include mountainous areas.

Molecular detection of Crimean-Congo hemorrhagic fever virus in ticks, Greece, 2012-2014.

Crimean-Congo hemorrhagic fever virus (CCHFV) is transmitted to humans mainly through the bite of infected ticks. In Greece, only one clinical case has been observed, in 2008, but the seroprevalence in humans is relatively high (4.2%). To have a first insight into the circulation of CCHFV in Greece, 2000 ticks collected from livestock during 2012-2014 were tested. CCHFV was detected in 36 of the 1290 (2.8%) tick pools (1-5 ticks per pool). Two genetic lineages were identified: Europe 1 and Europe 2. Most Europe 1 sequences were obtained from Rhipicephalus sanguineus sensu lato ticks, while most Europe 2 sequences were recovered from Rhipicephalus bursa ticks. The number of collected Hyalomma marginatum ticks (the principal vector of CCHFV) was low (0.5% of ticks) and all were CCHFV negative. Since it is not known how efficient ticks of the Rhipicephalus genus are as vectors of the virus, laboratory studies will be required to explore the role of Rhipicephalus spp. ticks in CCHFV maintenance and transmission.

Crimean-Congo hemorrhagic fever virus in ticks collected from livestock in Albania

Albania is a Balkan country endemic for Crimean-Congo hemorrhagic fever (CCHF). It was shown previously that CCHF virus (CCHFV) sequences from Albanian patients cluster into Europe 1 clade. Aim of the present study was to test for CCHFV ticks collected in several regions of Albania, and to determine the genetic lineage(s) of the CCHFV strains in relation with their geographic distribution. A total of 726 ticks (366 Hyalomma marginatum, 349 Rhipicephalus bursa and 11 Rhipicephalus sanguineus) collected from livestock during 2007–2014 were included in the study. Thirty of 215 (13.9%) tick pools were positive for CCHFV. Lineage Europe 1 was detected in H. marginatum ticks collected in the endemic region of Albania, while lineage Europe 2 was detected mainly in R. bursa ticks in various regions of the country. Both genetic lineages were detected in the CCHF endemic area (northeastern Albania), while only Europe 2 lineage was detected in the south of the country. A higher genetic diversity was seen among Europe 2 than Europe 1 Albanian sequences (mean distance 3.7% versus 1%), suggesting a longer evolution of AP92-like strains (Europe 2) in their tick hosts. The present study shows that besides CCHFV lineage Europe 1, lineage Europe 2 is also present in Albania. Combined with results from recent studies, it is concluded that lineage Europe 2 is widely spread in the Balkans and Turkey, and is associated mainly with R. bursa ticks (at least in this region). Its pathogenicity and impact to the public health remain to be elucidated.

Combination of RT-PCR and proteomics for the identification of Crimean-Congo hemorrhagic fever virus in ticks.

Crimean-Congo hemorrhagic fever (CCHF) is an emerging tick-borne zoonotic disease caused by the CCHF virus (CCHFV). In this study, an experimental approach combining RT-PCR and proteomics was used for the identification and characterization of CCHFV in 106 ticks from 7 species that were collected from small ruminants in Greece. The methodological approach included an initial screening for CCHFV by RT-PCR followed by proteomics analysis of positive and control negative tick samples. This novel approach allowed the identification of CCHFV-positive ticks and provided additional information to corroborate the RT-PCR findings using a different approach. Two ticks, Dermacentor marginatus and Haemaphysalis parva collected from a goat and a sheep, respectively were positive for CCHFV. The sequences for CCHFV RNA segments S and L were characterized by RT-PCR and proteomics analysis of tick samples, respectively. These results showed the possibility of combining analyses at the RNA and protein levels using RT-PCR and proteomics for the characterization of CCHFV in ticks. The results supported that the CCHFV identified in ticks are genetic variants of the AP92 strain. Although the AP92-like strains probably do not represent a high risk of CCHF to the population, the circulation of genetically diverse CCHFV strains could potentially result in the appearance of novel viral genotypes with increased pathogenicity and fitness.

Crimean-Congo hemorrhagic fever virus in ticks in Turkey: A broad range tick surveillance study

In Turkey, Crimean-Congo hemorrhagic fever (CCHF) outbreaks started in northern regions in 2002. Human cases still continue to increase and the disease spreads in many other provinces of Turkey. The ecological role of the vector tick species occurring in Turkey is not certain exactly. Therefore, we planned a broad range tick study in three different ecological and geographical areas extending from the West Black Sea regions down to the Central Anatolia. The aim of this study was to determine and characterize CCHFV molecularly in feeding-ticks collected from various wild and domestic animals and from humans as well as in questing and unfed ticks. In this study, 4283 tick samples derived from 21 tick species were collected from 76 villages and 10 central districts in total. All tick pools were screened for the presence of CCHFV RNA by two nested RT-PCRs. PCR assays were positive for 27 (3.6%) of 736 pools. CCHFV was detected in Hyalomma marginatum, Dermacentor marginatus, Rhipicephalus bursa, Rhipicephalus turanicus, Hyalomma excavatum and Haemaphysalis parva pools. As a result of the phylogenetic analysis, it was determined that the obtained CCHFV sequences are clustered into Europe 1 clade. CCHFV was detected among ticks obtained from cattle, goats, wild boar, hare, and the ground. The presence of CCHFV in ticks obtained from various domestic and wild hosts and the nature, and thereby the distribution patterns of the virus in different ecological areas were presented in this study. Furthermore, CCHFV was also detected in unusual tick species. Consequently, these results indicate that tick surveillance studies in large-scale and wide varieties contribute to the ecology and epidemiology of CCHF in that region, and can be used as an early-warning system.

Molecular epidemiology of Crimean–Congo hemorrhagic fever virus in ticks collected from western Iran

Background: Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease that is endemic in Africa, southeastern Europe, and Asia. Ticks are both the reservoir and the vector of the CCHF virus (CCHFV). Determining the virus infection rate of the tick population in different geographical regions is necessary todesign public health policies to prevent CCHF outbreaks. Objectives: To determine the prevalence, seasonal activity, and the frequency of CCHFV infection of the tick population in Hamadan province of west Iran. Methods: This cross-sectional study was conducted in 3 counties of Hamadan Province from June 2013 to May 2014. The study areas included both lowland (plains) and highland (mountains) and covered 5% of the villages where 10 herds per village of sheep and goats were randomly selected for hard tick collection. Results: We examined 983 sheep and goats, and 881 ticks were collected and identified before being preserved for molecular tests. The collected ticks belonged to 3 genera including, Rhipicephalus (95.6%, n = 842), Hyalomma (4.1%, n = 36) and Haemaphysalis (0.4%, n = 4). After species identification, 100 randomly selected ticks were analyzed using reverse transcriptase-polymerase chain reaction (RT-PCR) to detect viral infection. CCHFV infection was observed in 7 collected ticks, of which 4 belonged to R. sanguineus, 2 belonged to R. bursa, and one Hy. asiaticum. Conclusions: Hyalomma and Rhipicephalus ticks are the main vectors of CCHFV in Hamadan province where CCHF is focal and endemic. Keywords: Crimean-Congo hemorrhagic fever, Hamadan, Iran, molecular epidemiology, tick-borne diseases, zoonotic viral disease

Molecular detection of Crimean-Congo haemorrhagic fever virus in ticks collected from infested livestock populations in a New Endemic Area, South of Iran.

Crimean-Congo haemorrhagic fever (CCHF) is a viral zoonotic disease with potentially fatal systemic effects on man. We aimed to determine the presence of CCHF virus among collected ticks from domestic livestock from October 2012 to September 2013. A total of 1245 hard and soft ticks were collected from naturally infested ruminants in Marvdasht County, Fars Province, south of Iran. Nine tick species and one unidentified species in four disparate genera were detected. A total of 200 ticks were randomly selected and analysed by reverse transcription-polymerase chain reaction (RT-PCR) for the presence of CCHF virus genome. The viral genome was detected in 4.5% (9 samples) of the studied tick population. The infected ticks belonged to the species of Hyalomma marginatum' Hyalomma anatolicum and Rhipicephalus sanguineus. The viruses detected in these three tick species were clustered in the same lineage as Matin and SR3 strains in Pakistan and some other Iranian strains. These results indicate that the ticks were wildly infected with a genetically closely related CCHF virus in the region. Regular controls and monitoring of livestock to reduce the dispersion of ticks and providing information to those involved in high-risk occupations are urgently required.