Cross-sectional survey of Crimean-Congo hemorrhagic fever virus in the sultanate of Oman

Crimean-Congo haemorrhagic fever virus in ticks, domestic, and wild animals

Crimean-Congo haemorrhagic fever virus (CCHFV) poses a significant public health threat due to its potential for causing severe disease in humans and its wide geographic distribution. The virus, primarily transmitted by Hyalomma ticks, is prevalent across Africa, Asia, Europe, and the Middle East. Understanding the virus's spread among tick populations is crucial for assessing its transmission dynamics. Vertebrates play a key role in CCHF epidemiology by supporting tick populations and acting as virus carriers during viremia. Livestock, such as cattle, sheep, and goats, amplify the virus and increase tick numbers, posing zoonotic risks. Wildlife, while asymptomatic, can serve as reservoirs. Birds generally do not show signs of the virus but can introduce infected ticks to new regions. This review compiles information on CCHFV's tick vectors and vertebrate hosts, emphasizing their roles in the virus's transmission dynamics. Understanding these dynamics is essential for developing effective control and prevention strategies.

Status of Crimean-Congo haemorrhagic fever virus in ticks in Iran: A systematic review with meta-analysis

Crimean-Congo haemorrhagic fever (CCHF) is a re-emerging viral haemorrhagic fever causing outbreaks in Iran in the last 15 years. In this systematic review and meta-analysis, the status of Crimean-Congo haemorrhagic fever virus (CCHFV) in ticks would be evaluated. PubMed, Google Scholar and Web of Science were searched for peer-reviewed original papers published between 2000 and 1 July 2022. We included papers that evaluated the prevalence of CCHFV in individual ticks using reverse transcription polymerase chain reaction (RT-PCR). The pooled prevalence of CCHFV was 6.0% (95% confidence interval [CI]: 4.5-7.9%), with heterogeneity (I² = 82.706; P < 0.0001). The prevalence of CCHFV was higher related to regions with above sea level of 1001-1500 m (6.4%; 95% CI: 4.3-9.5%), an average temperature of ≤15 °C (8.3%; 95% CI: 5.6-12.0%), latitude of ≥36° (8.1%; 95% CI: 5.2-12.3%), an annual rainfall of 101-300 mm (9.8%; 95% CI: 6.1-15.4%) and humidity of ≥61% (10.2%; 95% CI: 5.1-19.3%). Due to the importance of CCHF, it is better to do new epidemiologic studies on ticks by related organizations and adjacent regions of some provinces in which human cases have been previously reported.

Crimean–Congo hemorrhagic fever in the Arab world: A systematic review

Crimean-Congo hemorrhagic fever (CCHF) is an important tick-borne viral infection with a fatality rate of up to 50% during outbreaks. Crimean-Congo hemorrhagic fever virus (CCHFV) is sustained in the ecosystem in benign form through vertical and horizontal transmission cycles involving tick vectors, wildlife, and livestock. Hyalomma ticks are considered the major source of human infection. CCHF occurs most often among butchers, slaughterhouse workers, and farmworkers through infected tick bites or/and contact with blood and tissues of infected livestock. The nosocomial transmission can occur in auxiliary nurses and physicians through contact with the infected patients. The widespread distribution of CCHFV most probably occurred by ticks on migratory birds, or through international travel and trade of livestock and wildlife. During co-infections of ticks and vertebrates, reassortment among genome segments could play a significant role in generating diversity, and hence, a potential risk for the emergence of novel variants. In this systematic review, we aimed to determine the epidemiology, transmission, distribution, mortality, and clinical features of CCHF in 22 Arab countries, comprising the Arab world. Based on the analysis of 57 studies published from 1978 to 2021, we found 20 tick species that could be associated with CCHFV transmission. During the 43-year period, 321 cases of CCHF were reported from 9/22 Arab countries, Iraq, Kuwait, UAE, Saudi Arabia, Oman, Sudan, Egypt, Tunisia, and Mauritania. The mean case fatality rate was 29% during various outbreaks. Individuals working in abattoirs/slaughter houses, livestock farms, and healthcare were most at risk. Contact with blood or body secretions from infected animals and patients was the most common mode of transmission. A number of different animals, including cattle, goats, sheep, and camels were reported to be seropositive for CCHFV. The highest seroprevalence was observed in camels (29%), followed by cattle (21%), goats (15%), and sheep (14%). We discuss these results in the context of policy-making and potential preventative measures that can be implemented to reduce the burden of CCHF in the Arab world.

Crimean-Congo Hemorrhagic Fever Outbreak in the North Region of Oman in August 2019: Case Series Study (Preprint).. [DOI: 10.2196/preprints.36495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

BACKGROUND

Crimean-Congo hemorrhagic fever (CCHF) is a viral zoonotic tickborne disease that has been linked to a high mortality rate in a number of nations. In Oman, the first case of CCHF was discovered in 1995. The Directorate of Disease Surveillance and Control received reports of four individuals with CCHF from various places in Northern Oman between August 17 and August 23, 2019 (during the Eid Adha festival).

OBJECTIVE

The aim of this study was to identify CCHF patients, determine the source and mechanism of transmission, and recommend preventive measures to avoid further outbreaks.

METHODS

We arranged for a field visit with teams from the Ministry of Agriculture, Fisheries and Municipality on the same day of notice (August 23-17, 2019) in the region, and a case series study was undertaken using a semistructured questionnaire.

RESULTS

The findings revealed that all of the patients were men (three were Omanis), ranging in age from 40 to 55 years. Three of the patients worked in slaughterhouses, and all patients had close contact with raw sheep tissues. Fever and gastrointestinal problems were the most common symptoms, with a case fatality rate of 25%. Late bleeding signs and coagulopathy were detected in the patient who died.

CONCLUSIONS

The causative agent was most likely CCHF virus, and the source of the outbreak was infected imported sheep through direct contact with contaminated biological tissues, based on symptoms, signs, lab tests, and the incubation period. All imported sheep must be tested and flagged at the main gates of the three ports in Oman’s north region.

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.

Ticks and Tick-Borne Diseases of Livestock in the Middle East and North Africa: A Review

Ticks are important vectors of an array of viral, bacterial and protozoan pathogens resulting in a wide range of animal and human diseases. There is limited information in the literature about tick species in the Middle East and North Africa (MENA) countries, even though they have suitable climate and vegetation for ticks and their hosts. We reviewed the occurrence of tick species and the pathogens they transmit from the MENA on published papers from 1901-2020. We found taxonomic records of 55 tick species infesting livestock representing the following eight genera: Ornithodoros, Otobius, Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, and Rhipicephalus. In addition, 15 pathogens were recorded causing diseases of significance, with Crimean-Congo hemorrhagic fever, theileriosis, babesiosis and anaplasmosis being widely distributed diseases in the region. In recent decades, there has been increasing trends in disease occurrence and movement associated with global movement of humans and global trade of animals. We suggest that disease control and prevention could be achieved effectively through good integration between public health, veterinary medicine and animal management, and ecological approaches. We recommend further research in the areas of tick ecology and tick born-disease transmission. Furthermore, we suggest evaluation and improvement of disease control policies in the region.

Zoonotic implications of camel diseases in Iran

Approximately 60% of all human pathogens and 75% of emerging infectious diseases are zoonotic (of animal origin). Camel zoonotic diseases can be encountered in all camel-rearing countries. In this article, all studies carried out on camel zoonotic diseases in Iran are reviewed to show the importance of camels for public health in this country. More than 900 published documents were systematically searched to find relevant studies from 1,890 until late 2018. The collected articles were classified according to the aetiological agents. In this study, 19 important zoonotic diseases were reported among Iranian camels including listeriosis, leptospirosis, plague, Q fever, brucellosis, campylobacteriosis, tuberculosis, pasteurellosis, clostridiosis, salmonellosis, Escherichia coli infections, rabies, camelpox, Middle East respiratory syndrome coronavirus, Crimean-Congo haemorrhagic fever, echinococcosis, cryptosporidiosis, toxoplasmosis and dermatophytosis, most of which belong to bacterial, viral, parasitic and fungal pathogens, respectively. Results show that camels are one of the most important sources of infections and diseases in human; therefore, continuous monitoring and inspection programs are necessary to prevent the outbreak of zoonotic diseases caused by this animal in humans.

Zoonotic Diseases in Oman: Successes, Challenges, and Future Directions

Objective: This article describes the situation analysis of endemic and emerging zoonoses, and includes prevention and control of zoonoses in Oman. It also suggests possible recommendations toward elimination and risk reduction of emerging zoonoses. Methods: Epidemiologic information has been drawn from official to assess the situation. There has been significant progress in reducing the risk of brucellosis, Middle East Respiratory Syndrome Coronavirus, Crimean-Congo hemorrhagic fever, and cutaneous leishmaniasis. Rabies, West Nile fever, Q fever, and cystic hydatid disease have been confined to wildlife or livestock. Results: There is an increasing threat of emerging and re-emerging zoonoses in Oman due to globalization of travel and trade, development activities, and impact of climate change and vector bionomics. Prevention, control, and subsequent elimination of zoonoses on a sustainable basis shall not be possible without intersectoral collaboration between the human and animal health sectors. There are challenges for establishing such strong collaboration and coordination mechanisms in Oman. Institutional and cultural barriers, data and resource sharing, and national capability for rapid and effective investigation of zoonotic infections and emerging zoonoses in humans and animal reservoirs are among others. Conclusions: In the light of achievements made on the prevention and control of zoonoses in Oman during the past decades, priority zoonoses should be identified for elimination, and continuous efforts should be made to further strengthen a holistic multidisciplinary and multisectorial approach for controlling zoonoses at source. Pivotal interventions would include urgent adoption of "One Health" strategic approach as well as establishment of a robust, integrated surveillance system with a strong laboratory investigation capacity to eliminate priority zoonoses and minimize the risk of entry, establishment, and spread of emerging zoonoses in Oman.

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.

Crimean-Congo Hemorrhagic Fever in Migrant Worker Returning from Oman to India, 2016

In January 2016, a migrant worker who returned home to India after becoming ill in Oman was confirmed to have Crimean-Congo hemorrhagic fever (CCHF). Physicians should include CCHF in the differential diagnosis for patients with hemorrhagic signs and a history of recent travel to any area where CCHF is endemic or prevalent.