Review 1: "Epidemiological Profile of Crimean-Congo Hemorrhagic Fever, Iraq, 2018"

Maryam Keshtkar-Jahromi

Epidemiological Profile of Crimean-Congo Hemorrhagic Fever, Iraq, 2018

by Ali Hazim Mustafa, Faris Lami, and Hanan Abdulghafoor Khaleel

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Published on Nov 29, 2023
www.medrxiv.org

Description

Abstract Background Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal tick-borne disease that is widely distributed in Africa and Eurasia countries. It is caused by the CCHF virus of the Nairovirus genus of the Bunyaviridae family.This study aims to describe the 2018 CCHF epidemic wave in Iraq and epidemiological pattern to assist implantation of preventive and control measures and adherence of physicians to the standard case definition.Methods This descriptive study reviewed all records of suspected and confirmed CCHF cases. Three types of data sources were used: the case investigation forms of all suspected cases, case sheets of all confirmed cases, and the laboratory results from the central public health laboratory.Results The total number of suspected cases was 143. Most of the cases were males (59.4%), 15-45 years old (62.2%), and live in urban areas (58.7%). About three quarters of the cases (68.5%) did not fit the standard case definition adopted by Iraq Center of Disease Control. Most of the suspected cases were reported in Diwaniya province (20.3%). Nearly half of them (64, 44.7%) occurred in June.Only 7.0% (n=10) of suspected cases were positive when tested by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). One third of confirmed cases (3, 30.0%) occurred in Diwaniya province. During the 2018 epidemic wave, there were 10 confirmed cases with 8 deaths and 2 improved cases.Conclusion Despite the fact that CCHF is uncommon in Iraq, sporadic cases or outbreaks could occur.Recommendations Given the known method of transmission, banning of random livestock slaughtering and the practice of raising livestock inside residential areas are expected to have a major role in CCHF infection control.

RR:C19 Evidence Scale rating by reviewer:

Not informative. The flaws in the data and methods in this study are sufficiently serious that they do not substantially justify the claims made. It is not possible to say whether the results and conclusions would match that of the hypothetical ideal study. The study should not be considered as evidence by decision-makers.

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Review: The paper describes 10 cases of CCHF in Iraq in 2018. I am aware of recent surge in CCHF cases in the country, but the data presented in this paper does not match other reports.

The confirmatory method has been described Elisa and/or PCR, but they describe only 10 PCR-confirmed cases out of 143 suspected cases. Confirmation rate of 7% is very low compared to recently published paper in 2023 listed below (27%). There is a gap and confirmed cases should be more than 10. There is no data on serology diagnosis which could be the reason as not all cases have a positive PCR is the specimen is not collected on the right time, processed correctly or they might not even be tested for PCR. Please explain where the serology data for these subjects are and how were they interpreted in diagnosis of cases.
- Atwan Z, Alhilfi R, Mousa AK, Rawaf S, Torre JDL, Hashim AR, Sharquie IK, Khaleel H, Tabche C. Alarming update on incidence of Crimean-Congo hemorrhagic fever in Iraq in 2023. IJID Reg. 2023 Nov 26;10:75-79. doi: 10.1016/j.ijregi.2023.11.018. PMID: 38173860; PMCID: PMC10762355.
The paper needs significant professional English edition.
Authors are only describing only cases of 2018. Can they show us how trend of cases have been reported from 2018 until 2023? This can be additive to the existing information, otherwise the data does not add much to our public knowledge. A more longitudinal epidemiological CCHF data from Iraq will justify this publication.
Case fatality rate is way too high (80%) while in the most recently 2023 publication is 38.5%. They might have only included severe cases who were hospitalized. The difference is so high that needs a good justification.
Table 4: Why ages are described with range. As there are only 10 cases and please describe their specific age.
Table 5: Antibiotics listed in the table are brand names. For example, what is Meronium? Is that Meropenem? What is Ciprodar? Is that Ciprofloxacin? Please use generic names.
Please add the above listed paper to your references.
Discussion does not support emergence and rise in number of cases. CCHF surges are multifactorial related to climate change, precipitation, rain fall, freezing temperatures, tick population, preventive measures, and etc. which are not mentioned in discussion. If you have a longitudinal curve on number of cases from 2018 to 2023, it will be clearer with easier interpretation.

Review 1: "Epidemiological Profile of Crimean-Congo Hemorrhagic Fever, Iraq, 2018"

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