Crimean-Congo Hemorrhagic Fever, Herat Province, Afghanistan, 2017

Niazi, Aziz‐ur‐Rahman; Jawad, Mohammad Jawed; Amirnajad, Ahmad; Durr, Peter A.

doi:10.3201/eid2508.181491

Cited by 14 publications

(18 citation statements)

References 8 publications

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“…143 The second most affected country in the EMR is Somalia reporting 75 414 cases and 1007 associated deaths since the outbreak started in 2017. Other countries in the region that reported imported cases of cholera in 2017 were Qatar (5), Saudi Arabia (5), UAE (12), and Iran (625). 144 There are concerns about the rise of antibiotic resistance against cholera, due to mobile genetic elements in Yemen.…”

Section: Bacterial Emerging and Re-emerging Infectious Diseasesmentioning

confidence: 99%

Emerging and Re-emerging Infectious Diseases in the WHO Eastern Mediterranean Region, 2001-2018

Mostafavi

Ghasemian

Abubakar

et al. 2021

Int J Health Policy Manag

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Background: Countries in the World Health Organization (WHO) Eastern Mediterranean Region (EMR) are predisposed to highly contagious, severe and fatal, emerging infectious diseases (EIDs), and re-emerging infectious diseases (RIDs). This paper reviews the epidemiological situation of EIDs and RIDs of global concern in the EMR between 2001 and 2018. Methods: To do a narrative review, a complete list of studies in the field was we prepared following a systematic search approach. Studies that were purposively reviewed were identified to summarize the epidemiological situation of each targeted disease. A comprehensive search of all published studies on EIDs and RIDs between 2001 and 2018 was carried out through search engines including Medline, Web of Science, Scopus, Google Scholar, and ScienceDirect. Results: Leishmaniasis, hepatitis A virus (HAV) and hepatitis E virus (HEV) are reported from all countries in the region. Chikungunya, Crimean Congo hemorrhagic fever (CCHF), dengue fever, and H5N1 have been increasing in number, frequency, and expanding in their geographic distribution. Middle East respiratory syndrome (MERS), which was reported in this region in 2012 is still a public health concern. There are challenges to control cholera, diphtheria, leishmaniasis, measles, and poliomyelitis in some of the countries. Moreover, Alkhurma hemorrhagic fever (AHF), and Rift Valley fever (RVF) are limited to some countries in the region. Also, there is little information about the real situation of the plague, Q fever, and tularemia. Conclusion: EIDs and RIDs are prevalent in most countries in the region and could further spread within the region. It is crucial to improve regional capacities and capabilities in preventing and responding to disease outbreaks with adequate resources and expertise.

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Section: Bacterial Emerging and Re-emerging Infectious Diseasesmentioning

confidence: 99%

Emerging and Re-emerging Infectious Diseases in the WHO Eastern Mediterranean Region, 2001-2018

Mostafavi

Ghasemian

Abubakar

et al. 2021

Int J Health Policy Manag

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“…Previous evidence shows that human-to-human transmission is plausible and nosocomial transmission has been reported before 24,25 . However, we expect this aspect of transmission to contribute marginally to the annual reported trends of CCHFV cases in Afghanistan as most infections arise outside the hospital environment and are linked to animal handling activities 15,16 .…”

Section: Discussionmentioning

confidence: 99%

“…In shaded pale grey, the 95% CrI and in solid blue, the median estimate. In black dots, monthly incident cases reported in two separate CCHF outbreaks in Herat: in 2008 as reported by Mofleh et al 15 , and 2017 -2018 as reported by Niazi et al, and Sahak et al 13,16 . In Panels D and E, yearly CCHF cases and deaths reported from Herat, against data (black) as reported by Sahak et al In orange, a one-off campaign for vaccinating 50% of humans over a three-month period.…”

Section: Figure 2: Model Trajectories Against Calibration Target Datamentioning

confidence: 92%

Transmission dynamics and vaccination strategies for Crimean-Congo haemorrhagic fever virus in Afghanistan: a modelling study

Vesga

Clark

Ayazi

et al. 2022

Preprint

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Background Crimean-Congo haemorrhagic fever virus (CCHFV) is a highly pathogenic virus for which a safe and effective vaccine is not yet available, despite being considered a priority emerging pathogen. Understanding transmission patterns and the use of potential effective vaccines are central elements of the future plan against this infection. Methods We design a modelling approach to explain viral transmission amongst livestock, and spillover transmission into humans. While doing this we assess the value of environmental drivers as proxy indicators of vector activity and systematically select the best model using deviance information criteria. Finally, we assess the impact of vaccination by simulating campaigns targeted to humans or livestock, and to high-risk subpopulations (i.e, farmers). We use real-world human and animal data from a CCHFV endemic area in Afghanistan (Herat) to calibrate our models. Findings Our model selection analysis shows that saturation deficit is the indicator that better explains tick activity trends in Herat and that recent increments in reported CCHFV cases in this area are more likely explained by increased surveillance capacity instead of changes in the background transmission dynamics. Modelling suggests that clinical cases only represent 31% (95% CrI 28%-33%) of total infections in this area. A vaccination campaign in humans would result in a much larger impact than livestock vaccination (266 vs 31 clinical cases averted respectively) and a more efficient option calculated as courses per case averted (35 vs 431 respectively. Targeted vaccination to farmers while impactful, also results in 19 courses per case averted (95% CrI 7-62) compared to targeting the general population (35 95% CrI 16-107) Interpretation CCHFV is endemic in Herat, and transmission cycles are well predicted by environmental drivers like saturation deficit. Vaccinating animals could result in less impactful and less efficient campaigns, and importantly targeted interventions to high-risk groups like farmers can offer a much more efficient approach to vaccine roll-out.

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“…Previous evidence shows that human-to-human transmission is plausible and nosocomial transmission has been reported before [ 33 , 34 ]. However, we expect this aspect of transmission to contribute marginally to the annual reported trends of CCHFV cases in Afghanistan as most infections arise outside the hospital environment and are linked to animal handling activities [ 15 , 16 ].…”

Section: Discussionmentioning

confidence: 99%

“…Herat reported CCHFV outbreaks in 2008 and 2017 with an estimated case fatality ratio (CFR) ranging from 22% to 33% in humans [ 15 , 16 ]. Seroprevalence studies carried out in the area have reported high IgG seroprevalence in livestock (~75%) and higher seroprevalence among humans involved in livestock activities (farming, animal husbandry, etc) [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Transmission dynamics and vaccination strategies for Crimean-Congo haemorrhagic fever virus in Afghanistan: A modelling study

Vesga

Clark²,

Ayazi

et al. 2022

PLoS Negl Trop Dis

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Background Crimean-Congo haemorrhagic fever virus (CCHFV) is a highly pathogenic virus for which a safe and effective vaccine is not yet available, despite being considered a priority emerging pathogen. Understanding transmission patterns and the use of potential effective vaccines are central elements of the future plan against this infection. Methods We developed a series of models of transmission amongst livestock, and spillover infection into humans. We use real-world human and animal data from a CCHFV endemic area in Afghanistan (Herat) to calibrate our models. We assess the value of environmental drivers as proxy indicators of vector activity, and select the best model using deviance information criteria. Finally we assess the impact of vaccination by simulating campaigns targeted to humans or livestock, and to high-risk subpopulations (i.e, farmers). Findings Saturation deficit is the indicator that better explains tick activity trends in Herat. Recent increments in reported CCHFV cases in this area are more likely explained by increased surveillance capacity instead of changes in the background transmission dynamics. Modelling suggests that clinical cases only represent 31% (95% CrI 28%-33%) of total infections in this area. Vaccination campaigns targeting humans would result in a much larger impact than livestock vaccination (266 vs 31 clinical cases averted respectively) and a more efficient option when assessed in courses per case averted (35 vs 431 respectively). Targeted vaccination of farmers is impactful and more efficient, resulting in 19 courses per case averted (95% CrI 7–62) compared to targeting the general population (35 courses 95% CrI 16–107) Conclusions CCHFV is endemic in Herat, and transmission cycles are well predicted by environmental drivers like saturation deficit. Vaccinating humans is likely to be more efficient and impactful than animals, and importantly targeted interventions to high risk groups like farmers can offer a more efficient approach to vaccine roll-out.

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Crimean-Congo Hemorrhagic Fever, Herat Province, Afghanistan, 2017

Cited by 14 publications

References 8 publications

Emerging and Re-emerging Infectious Diseases in the WHO Eastern Mediterranean Region, 2001-2018

Emerging and Re-emerging Infectious Diseases in the WHO Eastern Mediterranean Region, 2001-2018

Transmission dynamics and vaccination strategies for Crimean-Congo haemorrhagic fever virus in Afghanistan: a modelling study

Transmission dynamics and vaccination strategies for Crimean-Congo haemorrhagic fever virus in Afghanistan: A modelling study

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