Evidence for widespread infection of African bats with Crimean-Congo hemorrhagic fever-like viruses.

Marcel A Müller,Veronika M Cottontail,Peter Vallo,Petra Emmerich,Marco Tschapka,Erik Lattwein,Florian Gloza-Rausch,Eric M Leroy,Samuel Oppong,Gaël D Maganga,Stéphanie Devignot,Christian Drosten,Victor Max Corman,Jan Felix Drexler,Friedemann Weber,Tabea Binger

doi:10.1038/srep26637

Abstract

Crimean Congo hemorrhagic fever virus (CCHFV) is a highly virulent tick-borne pathogen that causes hemorrhagic fever in humans. The geographic range of human CCHF cases largely reflects the presence of ticks. However, highly similar CCHFV lineages occur in geographically distant regions. Tick-infested migratory birds have been suggested, but not confirmed, to contribute to the dispersal. Bats have recently been shown to carry nairoviruses distinct from CCHFV. In order to assess the presence of CCHFV in a wide range of bat species over a wide geographic range, we analyzed 1,135 sera from 16 different bat species collected in Congo, Gabon, Ghana, Germany, and Panama. Using a CCHFV glycoprotein-based indirect immunofluorescence test (IIFT), we identified reactive antibodies in 10.0% (114/1,135) of tested bats, pertaining to 12/16 tested species. Depending on the species, 3.6%–42.9% of cave-dwelling bats and 0.6%–7.1% of foliage-living bats were seropositive (two-tailed t-test, p = 0.0447 cave versus foliage). 11/30 IIFT-reactive sera from 10 different African bat species had neutralizing activity in a virus-like particle assay. Neutralization of full CCHFV was confirmed in 5 of 7 sera. Widespread infection of cave-dwelling bats may indicate a role for bats in the life cycle and geographic dispersal of CCHFV.

Highlights

Crimean Congo hemorrhagic fever virus (CCHFV; Genus Nairovirus, Family Bunyaviridae) is a tick-borne pathogen that has caused more than 10,000 documented human infections worldwide, with a case fatality proportion of approximately 10–30%1,2
Phylogenetic analyses as well as serological studies based on cross-reactivity in complement fixation tests suggest that all identified bat-associated nairoviruses belong to two novel serogroups that are distantly related to CCHFV7
114 of 1,135 (10.0%) sera from 12 of 16 bat species sampled between 2005 and 2009 in 4/5 countries reacted with recombinant CCHFV GP antigen

Summary

Introduction

Crimean Congo hemorrhagic fever virus (CCHFV; Genus Nairovirus, Family Bunyaviridae) is a tick-borne pathogen that has caused more than 10,000 documented human infections worldwide, with a case fatality proportion of approximately 10–30%1,2. Several studies suggested that tick-infested migratory birds may be responsible for the spatial distribution of CCHFV9–11. Phylogenetic analyses as well as serological studies based on cross-reactivity in complement fixation tests suggest that all identified bat-associated nairoviruses belong to two novel serogroups that are distantly related to CCHFV7. While we do not know the expected frequency of nairovirus viraemia in free-ranging bats, field studies on other RNA viruses with a viraemic infection pattern, including hepadnaviruses[19], hepaciviruses[17], filoviruses[21,22,23], and bunyaviruses[24,25], indicate very low virus detection rates. Serology is more suitable for the limited sample size that can be achieved in bat-related studies, as most bat species are too small to be bled without destruction

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