Duration of Maternal Antibodies against Canine Distemper Virus and Hendra Virus in Pteropid Bats

Jonathan H Epstein,Allyson Walsh,Michelle L Baker,Katey Pelican,Jennifer A Barr,Edward Dubovi,Shawn Todd,Gary Crameri,Peter Daszak,Angela J Davies,Mark D Fielder,Deborah Middleton,Lin-Fa Wang,Victoria Boyd,Brian Pope,Carlos Zambrana-Torrelio,Wanda Markotter

doi:10.1371/journal.pone.0067584

Abstract

Old World frugivorous bats have been identified as natural hosts for emerging zoonotic viruses of significant public health concern, including henipaviruses (Nipah and Hendra virus), Ebola virus, and Marburg virus. Epidemiological studies of these viruses in bats often utilize serology to describe viral dynamics, with particular attention paid to juveniles, whose birth increases the overall susceptibility of the population to a viral outbreak once maternal immunity wanes. However, little is understood about bat immunology, including the duration of maternal antibodies in neonates. Understanding duration of maternally derived immunity is critical for characterizing viral dynamics in bat populations, which may help assess the risk of spillover to humans. We conducted two separate studies of pregnant Pteropus bat species and their offspring to measure the half-life and duration of antibodies to 1) canine distemper virus antigen in vaccinated captive Pteropus hypomelanus; and 2) Hendra virus in wild-caught, naturally infected Pteropus alecto. Both of these pteropid bat species are known reservoirs for henipaviruses. We found that in both species, antibodies were transferred from dam to pup. In P. hypomelanus pups, titers against CDV waned over a mean period of 228.6 days (95% CI: 185.4–271.8) and had a mean terminal phase half-life of 96.0 days (CI 95%: 30.7–299.7). In P. alecto pups, antibodies waned over 255.13 days (95% CI: 221.0–289.3) and had a mean terminal phase half-life of 52.24 days (CI 95%: 33.76–80.83). Each species showed a duration of transferred maternal immunity of between 7.5 and 8.5 months, which was longer than has been previously estimated. These data will allow for more accurate interpretation of age-related Henipavirus serological data collected from wild pteropid bats.

Highlights

IntroductionOld world frugivorous bats of the genus Pteropus (family Pteropodidae) are reservoirs for important zoonotic paramyxoviruses, including Nipah virus and Hendra virus – both members of the genus Henipavirus (family Paramyxoviridae)
Old world frugivorous bats of the genus Pteropus are reservoirs for important zoonotic paramyxoviruses, including Nipah virus and Hendra virus – both members of the genus Henipavirus
Hendra virus is enzootic in pteropid bats in Australia, while Nipah and Nipah-like viruses have been identified in Pteropus species throughout Asia and in other related pteropodid bat species in Africa [2,3,4,5,6,7,8,9,10,11,12]

Summary

Introduction

Old world frugivorous bats of the genus Pteropus (family Pteropodidae) are reservoirs for important zoonotic paramyxoviruses, including Nipah virus and Hendra virus – both members of the genus Henipavirus (family Paramyxoviridae). Both Hendra and Nipah viruses have been associated with severe neurological and respiratory disease and high mortality rates in domestic animals and humans [1]. Field studies have largely relied on serological data to identify infection rates in free ranging bat populations. Serological studies of Nipah and Hendra virus antibodies in free-ranging pteropid bat colonies have found seroprevalence to be as high as 59% [4,16,17,18]. Viral isolation and molecular studies suggest a very low (,1%) incidence of infection [17,19]

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Results

Conclusion