Robust rapid diagnostics for CCHF in endemic seasons
Crimean-Congo hemorrhagic Fever Virus (CCHF) is of increasing consequence in endemic regions as global climate changes increase the length of dry hot weather, facilitating the expansion of host tick populations which carry the virus. The virus is carried by the Ixodid (Hyalomma) tick found on a range of cattle and camel species. CCHFV is endemic to Africa, the Balkans, Middle-East and Asia. In the animal reservoir it results in sub-clinical infection but in humans, infection can lead to rashes, fevers and leads to hemorrhagic disease with a fatality ranging between 10 -40%. Mazzola LT et al., in their article discuss the importance of improved diagnostics for CCHFV and discuss the pros and cons of methods which have been reported in published literature and discussed the options for serological and RT-PCR based tests as LDT and commercial assays (1). The article however gave a limited statement about the reasons for the spread of CCHFV and this Letter aims to expand on that aspect.
CCHFV in endemic regions has been associated with the Muslim religious festival of Eid-ul Azha when a large number of animal sacrifices occur, leading to increased contact between individuals who are not usually involved in animal husbandry or meat handling (2, 3). This change in the pattern of animal handling together with the influx of animals into urban areas for the festival increases contact with possibly infected animals, increasing risk of CCHF.
Of note, the CCHF prevalence map used from WHO dated 2017 (4) identifies Pakistan as risk region with 5 – 49 cases of CCHF reported each year. Our laboratory performs clinical testing or CCHFV and reported 131 cases of CCHF in 2018. Testing is performed using a commercial assay from Altona Diagnostics, GmBH, and results are reported within 24 h of the specimen being received. This data indicates Pakistan is amongst the highest category of risk for CCHFV infections worldwide. Given that dengue fever is also prevalent in the same region and is part of differential diagnosis for CCHF in Pakistan, there is value in rapid diagnosis using a robust rapid RT-PCR assay in high risk cases even though it may be at an increased cost. Therefore, in CCHFV endemic regions having a rapid robust assay for diagnosis of acute infections is extremely important.
1. Mazzola LT, Kelly-Cirino C. Diagnostic tests for Crimean-Congo haemorrhagic fever: a widespread tickborne disease. BMJ Glob Health. 2019;4(Suppl 2):e001114.
2. Rai MA, Khanani MR, Warraich HJ, Hayat A, Ali SH. Crimean-Congo hemorrhagic fever in Pakistan. J Med Virol. 2008;80(6):1004-6.
3. Leblebicioglu H, Sunbul M, Memish ZA, Al-Tawfiq JA, Bodur H, Ozkul A, et al. Consensus report: Preventive measures for Crimean-Congo Hemorrhagic Fever during Eid-al-Adha festival. Int J Infect Dis. 2015;38:9-15.
4. WHO. Introduction to Crimean-Congo Haemorrhagic Fever. World Health Organization. Geneva, Switzerland2018. p. https://www.who.int/emergencies/diseases/crimean-congo-haemorrhagic-feve....