Egyptian rousette bats maintain long-term protective immunity against Marburg virus infection despite diminished antibody levels

Amy J Schuh,Tara K Sealy,Brian R Amman,Jessica R Spengler,Stuart T Nichol,Jonathan S Towner

doi:10.1038/s41598-017-07824-2

Amy J Schuh, Tara K Sealy + Show 4 more

Open Access

https://doi.org/10.1038/s41598-017-07824-2

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Abstract

Although bats are natural reservoir hosts for numerous zoonotic viruses, little is known about the long-term dynamics of the host immune response following infection and how these viruses are maintained in nature. The Egyptian rousette bat (ERB) is a known reservoir host for Marburg virus (MARV). Following infection of ERBs with MARV, virus-specific IgG antibodies are induced but rapidly wane and by 3 months post-infection the bats are seronegative. To determine whether reinfection of ERBs plays a role in MARV maintenance, we challenge groups of ERBs that were “naturally” or experimentally infected with MARV 17–24 months prior. No bats in either group exhibit evidence of MARV replication or shedding and all bats develop virus-specific secondary immune responses. This study demonstrates that infection of ERBs with MARV induces long-term protective immunity against reinfection and indicates that other factors, such as host population dynamics, drive MARV maintenance in nature.

Highlights

Bats have been implicated as natural reservoir hosts for numerous zoonotic viruses including coronaviruses[1], filoviruses[2], lyssaviruses[3] and paramyxoviruses[4, 5]
The virus infection and immune response dynamics following reinfection with Marburg virus (MARV) are in stark contrast to those observed following primary infection, where the virus can be detected in the blood from 1–16 days post infection (DPI) infection (100% of bats for a mean duration of 6.0 d)[11], the oral mucosa from 5–19 DPI (91.7% of bats for a mean duration of 4.6 d)[11] and the spleen up to 28 DPI (66.7% of bats at this time point)[8], and MARV IgG antibody levels are undetectable through 7 DPI, begin to rise at 9 DPI and peak between 14 and 28 DPI8–11
Following subcutaneous challenge with a moderately high dose of MARV, virus was not detected in daily blood or oral swab specimens taken through 14 days post challenge (DPC) and axillary lymph node, gonad, liver, salivary gland or spleen tissue taken at 21 DPC

Summary

Introduction

Bats (order Chiroptera) have been implicated as natural reservoir hosts for numerous zoonotic viruses including coronaviruses[1], filoviruses[2], lyssaviruses[3] and paramyxoviruses[4, 5]. MARV IgG antibody positive* (relative to time post primary infection of group 1 bats) 14–56 d 14–56 d 14–56 d 14–56 d 14–42 d 7–8 m 8 m 7 m 7–8 m 7–8 m and a 21-day latent period predicted a prevalence of active infection (

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