Development of a novel recombinant ELISA for the detection of Crimean-Congo hemorrhagic fever virus IgG antibodies

AbstractCrimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral infection caused by Crimean-Congo hemorrhagic fever virus (CCHFV). Serological screening of CCHF is important and current ELISA use antigens prepared from virus which is expensive due to requirement of high bio-containment facilities. In this study, we aimed to develop a new recombinant ELISA. For this purpose, CCHFV genome were expressed as 13 proteins in E. coli and among them abundantly purified recombinant Nucleocapsid protein (rNP) and Mucin-like variable domain (rMLD) were used as antigen in ELISA (Rec-ELISA). Rec-ELISA using rNP, rMLD and a combination of both (rNP/rMLD) were probed with acute (n = 64; collected between days 1 and 7 after onset of symptoms), convalescent (n = 35; collected 8 days after onset of symptoms), consecutive sera (n = 25) of confirmed CCHF cases and control sera (n = 43). The sensitivity and specificity of Rec-ELISA using rNP/rMLD were 73% and 98% in acute cases and 97% and 98% in convalescent cases. The median interquartile absorbance value to discriminate the acute and convalescent phases of CCHF was significantly higher with ELISA using rNP/rMLD (P < 0.0001) compared to rNP (P > 0.05) and rMLD (P = 0.001). These results indicate that the Rec-ELISA using rNP/rMLD may be very useful to diagnose convalescent CCHF cases especially in field studies.

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Phylogenetic Analysis of Crimean-Congo Hemorrhagic Fever Virus in Inner Mongolia, China

10.1101/2021.06.06.447231 ◽

2021 ◽

Author(s):

Yunyi Kong ◽

Chao Yan ◽

Xiaodong Liu ◽

Lingling Jiang ◽

Gang Zhang ◽

...

Keyword(s):

South African ◽

Inner Mongolia ◽

Evolutionary Relationship ◽

Hemorrhagic Fever ◽

Fever Virus ◽

Crimean Congo Hemorrhagic Fever ◽

Hemorrhagic Fever Virus ◽

Complete Sequences ◽

And Control ◽

New Evidence

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne arbovirus that can cause bleeding and death in humans. The mortality rate in humans is between 5 to 30%. The pathogen is prevalent in more than 30 countries in the world. In China, reports of strains of CCHFV have been concentrated in Xinjiang province. However, the CCHFV strain has never been reported in Inner Mongolia, China. This study reports new CCHFV strains, HANM-18, from Hyalomma asiaticum and Hyalomma dromedarii collected in Alxa Left Banner and Alxa Right Banner in Inner Mongolia. Complete sequences of CCHFV were obtained by the nested PCR technique and used for analyzing the identity and evolutionary relationship with other CCHFV strains. Interestingly, our results showed that the S and L fragments of the HANM-18 strain had high degrees of identity with Xingjiang isolate strains, and the M fragment had significant identity with South African isolates. These analyses also indicate that the HANM-18 strain may have been prevalent in northwest Inner Mongolia for many years. This discovery will be helpful in CCHF prevention and control in Inner Mongolia, and it also adds new evidence to the epidemiology of CCHF in China.

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