New circulating genomic variant of Crimean-Congo hemorrhagic fever virus in Iran

Medically Significant Vector-Borne Viral Diseases in Iran

Vector-borne viral diseases (VBVDs) continue to pose a considerable public health risk to animals and humans globally. Vectors have integral roles in autochthonous circulation and dissemination of VBVDs worldwide. The interplay of agricultural activities, population expansion, urbanization, host/pathogen evolution, and climate change, all contribute to the continual flux in shaping the epidemiology of VBVDs. In recent decades, VBVDs, once endemic to particular countries, have expanded into new regions such as Iran and its neighbors, increasing the risk of outbreaks and other public health concerns. Both Iran and its neighboring countries are known to host a number of VBVDs that are endemic to these countries or newly circulating. The proximity of Iran to countries hosting regional diseases, along with increased global socioeconomic activities, e.g., international trade and travel, potentially increases the risk for introduction of new VBVDs into Iran. In this review, we examined the epidemiology of numerous VBVDs circulating in Iran, such as Chikungunya virus, Dengue virus, Sindbis virus, West Nile virus, Crimean-Congo hemorrhagic fever virus, Sandfly-borne phleboviruses, and Hantavirus, in relation to their vectors, specifically mosquitoes, ticks, sandflies, and rodents. In addition, we discussed the interplay of factors, e.g., urbanization and climate change on VBVD dissemination patterns and the consequent public health risks in Iran, highlighting the importance of a One Health approach to further surveil and to evolve mitigation strategies.

Distribution pattern of Crimean-Congo Hemorrhagic Fever in Asia and the Middle East

Crimean-Congo Hemorrhagic Fever (CCHF) is one of the most important vector-borne diseases of zoonotic potential that can be acquired following the bite of the Hyalomma species of ticks. It is a highly prevalent disease in Asia and the Middle East. The risk factors of this disease are contact with infected tissue, blood, patient, or livestock in the acute viremic phase, infected tick bites, or the manual removal of ticks. The disease is clinically described as progressive hemorrhages, fever, and pain in musculature. Biochemical tests reveal elevated levels of creatinine phosphokinase, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase. Clotting time is prolonged in pro-thrombin tests, and pathogenesis is mostly related to the disruption of the epithelium during viral replication and indirectly by secreting cytotoxic molecules. These molecules cause endothelial activation and result in the loss of function. Supportive therapy is given through blood or plasma infusions to treat or manage the patients. According to the most advanced studies, CCHF can be treated by Ribavirin, which is an antiviral drug that shows excellent results in preventing the disease. Health-care staff are more prone to infection. The hemorrhagic phase represents a high risk for accidental exposures. This literature review presents a comprehensive overview of the viral epidemiology, zoonotic perspectives, and significant risk factors of CCHF in various Middle East and Asian countries. Furthermore, the pathophysiology and preventive strategies of CCHF have also been discussed as well as legislation and policies regarding public outreach programs, research, and development aimed at infection prevention and control that are required at a global level.

Crimean-Congo Hemorrhagic Fever Virus in Asia, Africa and Europe

The global spread of ticks and various tick-borne viruses (TBVs) suggests the possibility of new tick-borne diseases emerging. Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging TBV of the Nairoviridae family that causes serious disease that can be fatal in humans. CCHFV endemic foci can be found in Africa, Asia, the Middle East, and South-Eastern Europe, and has spread to previously unaffected regions and nations, such as Spain, over the last two decades. In this review, we discuss the current situation of CCHFV in Asia, Africa and Europe based on existing knowledge, and we discuss driving factors in the distribution and transmission of the virus, such as the spread of tick vector species and host reservoirs.

Vector-borne diseases in Iran: epidemiology and key challenges

Vector-borne diseases have become a global health concern in recent decades as a result of global warming, globalization, growth in international trade and travel, use of insecticide and drug resistance. This review study addressed the key vector-borne diseases and their current status in Iran to emphasize the requirements for further research on vector-borne diseases. The dispersion patterns of these diseases differ in various regions. Some of them such as Crimean-Congo hemorrhagic fever, and Q fever are distributed all across Iran, whereas some others such as plague, leishmaniasis, tularemia, and malaria are restricted to specific areas. The high prevalence of vectors throughout the country necessitates enhancing the monitoring and surveillance of emerging and reemerging vector-borne diseases and their potential vectors.

Clinical and molecular epidemiology of Crimean-Congo hemorrhagic fever in Oman

BACKGROUND

Crimean-Congo hemorrhagic fever (CCHF) is a serious disease with a high fatality rate reported in many countries. The first case of CCHF in Oman was detected in 1995 and serosurveys have suggested widespread infection of humans and livestock throughout the country.

METHODOLOGY

Cases of CCHF reported to the Ministry of Health (MoH) of Oman between 1995 and 2017 were retrospectively reviewed. Diagnosis was confirmed by serology and/or molecular tests in Oman. Stored RNA from recent cases was studied by sequencing the complete open reading frame (ORF) of the viral S segment at Public Health England, enabling phylogenetic comparisons to be made with other S segments of strains obtained from the region.

FINDINGS

Of 88 cases of CCHF, 4 were sporadic in 1995 and 1996, then none were detected until 2011. From 2011-2017, incidence has steadily increased and 19 (23.8%) of 80 cases clustered around Eid Al Adha. The median (range) age was 33 (15-68) years and 79 (90%) were male. The major risk for infection was contact with animals and/or butchering in 73/88 (83%) and only one case was related to tick bites alone. Severe cases were over-represented: 64 (72.7%) had a platelet count < 50 x 109/L and 32 (36.4%) died. There was no intrafamilial spread or healthcare-associated infection. The viral S segments from 11 patients presenting in 2013 and 2014 were all grouped in Asia 1 (IV) lineage.

CONCLUSIONS

CCHF is well-established throughout Oman, with a single strain of virus present for at least 20 years. Most patients are men involved in animal husbandry and butchery. The high mortality suggests that there is substantial under-diagnosis of milder cases. Preventive measures have been introduced to reduce risks of transmission to animal handlers and butchers and to maintain safety in healthcare settings.

Co-circulation of Crimean-Congo Hemorrhagic Fever virus strains Asia 1 and 2 between the border of Iran and Pakistan

Crimean-Congo Hemorrhagic Fever (CCHF) is a tick-borne viral disease that is transmitted by numerous species of ticks, which serve both as a reservoir and vector of CCHF virus (CCHFV). Molecular and serological tests were undertaken on hard ticks (Ixodidae spp.) and samples from livestock were collected in 2015 from Chabahar County in Southeast Iran. Using RT-PCR, the ticks were tested for the presence of CCHFV. In addition, seven livestock were serologically tested for the presence of IgG antibodies using an ELISA test. IgG antibodies against CCHFV were detected in one of 7 of the livestock that were tested. In total, 49 ticks including five species: Rhipicephalus sanguineus, Hyalomma anatolicum, Hy. asiaticum, Hy. dromedarii and Hy. marginatum with a prevalence of 46.9%, 32.7%, 4.1%, 4.1% and 2.1% respectively were identified. CCHFV was detected in three ticks among 49 collected ticks. The ticks infected with CCHFV belonged to the genus Hyalomma and Rhipicephalus. Phylogenetic analysis demonstrated that two sequences clustered in clade IV (Asia-1) and one sequence was located within clade IV (Asia-2). Most of the animal and human CCHF cases of the country are reported from Sistan and Baluchistan provinces. Regular monitoring programs in the tick population and livestock are needed in the future.

Current status of Crimean-Congo haemorrhagic fever in the World Health Organization Eastern Mediterranean Region: issues, challenges, and future directions

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The paper provides a comprehensive overview of the status of Crimean-Congo hemorrhagic fever (CCHF) in countries across the World Health Organization Eastern Mediterranean Region (WHO EMR).

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The increasing incidence of CCHF disease in the region and its spread to new geographical areas is highlighted.

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Knowledge gaps concerning the burden and circulation of CCHF virus in the WHO EMR are identified.

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A strategic framework is described, which details the research and development work necessary to curb the ongoing and new threats posed by CCHF virus.

Crimean-Congo haemorrhagic fever (CCHF) is the most widespread, tick-borne viral disease affecting humans. The disease is endemic in many regions, such as Africa, Asia, Eastern and Southern Europe, and Central Asia. Recently, the incidence of CCHF has increased rapidly in the countries of the World Health Organization Eastern Mediterranean Region (WHO EMR), with sporadic human cases and outbreaks of CCHF being reported from a number of countries in the region. Despite the rapidly growing incidence of the disease, there are currently no accurate data on the burden of the disease in the region due to the different surveillance systems used for CCHF in these countries. In an effort to increase our understanding of the epidemiology and risk factors for the transmission of the CCHF virus (CCHFV; a Nairovirus of the family Bunyaviridae) in the WHO EMR, and to identify the current knowledge gaps that are hindering effective control interventions, a sub-regional meeting was organized in Muscat, Oman, from December 7 to 9, 2015. This article summarizes the current knowledge of the disease in the region, identifies the knowledge gaps that present challenges for the prevention and control of CCHFV, and details a strategic framework for research and development activities that would be necessary to curb the ongoing and new threats posed by CCHFV.

Crimean-Congo hemorrhagic fever cases in the North of Iran have three distinct origins

An on-going surveillance program on Crimean-Congo haemorrhagic fever virus (CCHFV) in Iran has been launched since 2000. An outbreak of CCHF occurred in northern Iran between June and July 2015. Three cases were involved in this outbreak. One patient died after admission to hospital, and the others were treated successfully. Phylogenetic analysis showed that three sequences obtained from Iranian patients grouped within clade IV (Asia-1), clade V (Europe) and clade VI (Greece). The partial sequence of the strain Noshahr59 (KT588642) showed the highest similarity with other strains isolated from Russia, Kosovo and Turkey (Clade V, Europe). The genome sequence of the strain Chalous65 (KT588640) showed 100% homology to the strain AP29 isolated from Greece (DQ211638). The genome sequence of the strain Noshahr43 (KT588641) showed 88% similarity to the Pakistani and previously reported Iranian strains (AF527810, AJ538198, AY366379 and AY366373). These data support previous studies, which showed a distinct similarity between Iranian S segments of CCHFV strains with other strains within clade IV (Asia-1) and clade V (Europe). In addition, clade VI was detected for the first time in Iran. Moreover, strain Chalous65 with similar genetic characteristics to strain AP29 from Greece was isolated from a fatal human case.

Phylogeny of tick-derived Crimean-Congo hemorrhagic fever virus strains in Iran

The presence of Crimean-Congo hemorrhagic fever virus (CCHFV) in Iran was assessed by collecting ticks from Golpayegan, Isfahan Province. Real time RT-PCR was used to detect the CCHFV RNA in the tick population and the origins of the viral sequences were determined. The CCHFV RNA was detected in 5.2% of 492 ticks collected from livestock in different regions of Golpayegan. The tick species that tested positive for the presence of CCHFV RNA included Hyalomma, Rhipicephalus and Haemaphysalis species. Phylogenetic analysis using the partial S-segment indicated that eight sequences clustered in clade IV (Asia-1) and three other sequences aligned within clade VI (Europe) with other CCHFV strains from Kosovo (Kosova1917) and Russia (Kashmanov).

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Crimean-Congo Hemorrhagic Fever Virus Clade IV (Asia 1) in Ticks of Western Iran

Crimean-Congo Hemorrhagic Fever virus (CCHFV) is transmitted through the bite of an infected tick, or by direct contact with CCHFV-infected patients' blood or the products of infected livestock. In 2012, ticks were collected in eight regions of Lorestan Province, Iran. In total, 434 ticks were collected. Reverse transcriptase polymerase chain reaction was used for the detection of CCHFV RNA. Of 434 ticks, 419 (96.6%) ticks were from the family Ixodidae (hard ticks) and 15 (3.5%) ticks were from the family Argasidae (soft ticks). The presence of CCHFV RNA was detected in 29 (6.7%) of 434 ticks. The infected tick species include Hyalomma asiaticum (n = 7, 7.4%), Hyalomma anatolicum (n = 12, 13.2%), Hyalomma marginatum (n = 1, 16.7%), and Rhipicephalus sanguineus (n = 9, 4.3%). These empirical data demonstrated that the majority of CCHFV-positive ticks belonged to the Ixodidae. None of the Argasidae and Haemaphysalis sulcata species was infected with CCHFV. The phylogenetic analyses of the tick-derived CCHFV strains revealed that all 29 viral strains fell in clade IV (Asia 1). The most abundant species of tick collected in this study was R. sanguineus followed by different species of Hyalomma. Given the infection rate among collected ticks, H. marginatum was the most abundant infected tick species (16.7%) followed by H. anatolicum (13.2%), H. asiaticum (7.4%), and R. sanguineus (4.3%).

Consensus report: Preventive measures for Crimean-Congo Hemorrhagic Fever during Eid-al-Adha festival

Crimean-Congo hemorrhagic fever (CCHF) is endemic in Eurasian countries such as, Turkey, Pakistan, Afghanistan and Iran. CCHF virus is spread by the Hyalomma tick, which is found mainly on cattle and sheep. Muslim countries, in which these animals are sacrificed during Eid-Al-Adha, are among the countries where CCHF is endemic, and it has been observed that CCHF is associated with practices surrounding the Eid-ad-Adha festival. The dates for Eid-Al-Adha drift 10 days earlier in each year according to Georgian calendar. In previous years Eid-al-Adha occurred in autumn-winter months however in the next 10-15 years it will be take place in the summer months when CCHF is more prevalent. This may lead to a rise in the number of cases due to increased dissemination of CCHF virus with uncontrolled animal movements in and between countries. This consensus report focuses on the variable practices regarding animal handling in different regions and possible preventative measures to reduce the incidence of CCHF. Environmental hygiene and personal protection are essential parts of prevention. There is a need for international collaborative preparedness and response plans for prevention and management of CCHF during Eid-Al-Adha in countries where the disease is prevalent.

First phylogenetic analysis of a Crimean-Congo hemorrhagic fever virus genome in naturally infected Rhipicephalus appendiculatus ticks (Acari: Ixodidae)

Crimean-Congo haemorrhagic fever (CCHF) is a potentially fatal systemic viral disease in many parts of the world, including Iran. The nationwide incidence of human CCHF in endemic areas was 870 confirmed cases with 126 deaths (case fatality rate, CFR = 17.6 %) in the decade leading to 2012. The detection of the CCHF virus (CCHFV) genome in tick vectors is of fundamental importance for identifying these ticks as potential reservoirs of CCHFV infection. From May to October 2013, following detection of four new clinical cases resulting in two deaths in the city of Mashhad (northeast Iran), hard ticks were recovered from infested livestock in 40 villages in Khorasan-Razavi province and examined by the microscopic method for species identification. About a quarter of the ticks were then subjected to reverse-transcription polymerase chain reaction (RT-PCR) to detect the CCHFV genome. The PCR products were then sequenced, and their phylogenetic lineages were determined. A total of 407 hard ticks were captured, representing seven different species in two distinct genera. Members of the genus Hyalomma were widely distributed in all but two of the villages studied, and this was also the most frequent (83.3 %) tick genus. Of 105 adult ticks subjected to RT-PCR, four (3.8 %) ticks were found positive for the CCHFV genome. One brown ear tick, Rhipicephalus appendiculatus, was found to be naturally infected for the first time anywhere in the world. Ticks of Hyalomma asiaticum, Hyalomma marginatum, and Rhipicephalus turanicus were also found to be naturally infected with CCHFV. CCHFV found in these four different tick species were clustered in the same lineage with the Matin and SR3 strains from Pakistan and some other strains from Iran, indicating that these tick species were naturally infected with genetically closely related CCHFV in the region. The presence of CCHFV infection in four different hard tick species was confirmed using RT-PCR in northeast Iran. Part of this infection was attributed to Rh. appendiculatus, which is thus a potential new natural vector of CCHFV in Iran. It is also confirmed by phylogenetic analysis that CCHFV in this region is genetically closely related, even in the different tick species.

Molecular epidemiology of Crimean-Congo hemorrhagic fever virus detected from ticks of one humped camels (Camelus dromedarius) population in northeastern Iran

A comprehensive study was conducted on camel ticks to assess the epidemiological aspects of the infection in camels. From May 2012 to January 2013, 11 cities and towns from the Khorasan provinces, northeastern Iran, were randomly selected as a "cluster" and at least 14 camels were sampled from each cluster. A total of 200 camels were examined in this study, reverse transcriptase polymerase chain reaction was used for the detection of the Crimean-Congo hemorrhagic fever virus (CCHFV) genome. Tick infestation was observed in 171 of the 200 camels, 480 ixodid ticks were collected, and one genus was identified as Hyalomma. Four species were reported to be the major tick species infesting camels. Among these, Hyalomma dromedarii was the most predominant tick species (90.7 %), followed by H. anatolicum (6 %), H. marginatum (2.9 %), and H. asiaticum (0.4 %). The genome of the CCHFV was detected in 49 (10.2 %) of the 480 ticks. The CCHFV RNA was detected in two of the four tick species, and the viral genome was detected from tick samples in three South Khorasan cities. The positivity rate of ticks was as follows: Boshroyeh, 25 out of 480 (5.2 %); Birjand, 17 out of 480 (3.5 %); and Nehbandan, 7 out of 480 (1.5 %). We recommend the use of acaricides to prevent disease transmission to humans and to reduce the tick population in camels. Care should be taken by abattoir workers and by those who work closely with camels.

Crimean-Congo hemorrhagic fever in Iran

The presence of Crimean-Congo hemorrhagic fever virus (CCHFV) in Iran was first identified in studies of livestock sera and ticks in the 1970s, but the first human infection was not diagnosed until 1999. Since that time, the number of cases of CCHF in Iran has markedly increased. Through January 2012, articles in the published literature have reported a total of 870 confirmed cases, with 126 deaths, for a case fatality rate (CFR) of 17.6%. The disease has been seen in 26 of the country's 31 provinces, with the greatest number of cases in Sistan and Baluchestan, Isfahan, Fars, Tehran, Khorasan, and Khuzestan provinces. The increase in CCHF in Iran has paralleled that in neighboring Turkey, though the number of cases in Turkey has been much larger, with an overall CFR of around 5%. In this article, we review the features of CCHF in Iran, including its history, epidemiology, animal and tick reservoirs, current surveillance and control programs, diagnostic methods, clinical features and experience with ribavirin therapy, and consider possible explanations for the difference in the CFR of CCHF between Iran and Turkey. The emergence of CCHF in Iran calls for countermeasures at many levels to protect the population, but also provides opportunities for studying the epidemiology, diagnosis and management of the disease.