CCHF virus variants in Pakistan and Afghanistan: Emerging diversity and epidemiology
Section snippets
Background
Crimean Congo hemorrhagic fever virus (CCHFV) belongs to the genus Nairovirus within the family Bunyaviridae [1]. It contains single stranded, three negative sense RNA segments known as small (S), medium (M) and large (L) which encode nucleocapsid protein, glycoproteins (Gn and Gc) and viral RNA polymerase, respectively [2], [3], [4]. Based on geographical origin and phylogenetic analyses of S gene segment, CCHFVs has been classified into seven distinct genetic groups; African group 1 comprises
Objectives
The purpose of the current study was to understand the genetic diversity of CCHF viruses from Pakistan and Afghanistan at a molecular level through analyses of partial S-segment sequence.
Sample selection and collection
The study was carried out from January to December 2011 at the National Institute of Health in Islamabad, Pakistan. One hundred blood samples were collected from suspected patients of CCHF. The case definition used for identification of CCHF patients included fever, malaise, myalgia, bleeding from various orifices and low platelet count. CCHF was confirmed by reaction of IgM antibody using ELISA kit (Biological Diagnostic Supplies Limited, BDSL®) in accordance with the manufacturer’s
Results
Out of one hundred blood samples collected from suspected cases of CCHF during 2011, 49 (49%) samples tested positive for CCHF either by ELISA/RT-PCR or both. Out of 49, ten samples were positive for IgM antibodies on ELISA, fourteen for CCHF virus RNA by PCR while twenty five were found positive for both IgM antibodies and RNA (Table 2). Positive samples were received from five districts of Baluchistan province (Killa Abdullah, Loralai, Pishin, Quetta, and Zhob) and Afghanistan (Kandahar) (
Discussion
Pakistan is an agricultural country where a large proportion of population resides in villages and towns. There is an extensive variety of entomological disease vectors and endemic pathogens across the country resulting in a large potential for human exposure. The causality of vector borne diseases is often directly associated with social upheaval and economic status of people living in rural areas [14]. Baluchistan being the largest province of country covers almost 43% of the country’s
Funding
No current external funding sources for this study.
Competing interests
None declared by any co-author.
Ethical approval
The study was approved by the ethical committee of National Institute of Health, Islamabad, Pakistan. Additionally, none of the identities related to patients have been disclosed at any stage.
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