Bat trait, genetic and pathogen data from large-scale investigations of African fruit bats, Eidolon helvum

Abstract

Bats, including African straw-coloured fruit bats (Eidolon helvum), have been highlighted as reservoirs of many recently emerged zoonotic viruses. This common, widespread and ecologically important species was the focus of longitudinal and continent-wide studies of the epidemiological and ecology of Lagos bat virus, henipaviruses and Achimota viruses. Here we present a spatial, morphological, demographic, genetic and serological dataset encompassing 2827 bats from nine countries over an 8-year period. Genetic data comprises cytochrome b mitochondrial sequences (n=608) and microsatellite genotypes from 18 loci (n=544). Tooth-cementum analyses (n=316) allowed derivation of rare age-specific serologic data for a lyssavirus, a henipavirus and two rubulaviruses. This dataset contributes a substantial volume of data on the ecology of E. helvum and its viruses and will be valuable for a wide range of studies, including viral transmission dynamic modelling in age-structured populations, investigation of seasonal reproductive asynchrony in wide-ranging species, ecological niche modelling, inference of island colonisation history, exploration of relationships between island and body size, and various spatial analyses of demographic, morphometric or serological data.

Figure 1. Map showing location of E. helvum sampling locations for genetic and serological analyses.

Shading represents the distribution range of E. helvum. Sampling locations are numbered as in Table 1 (available online only). Adapted with permission from Mickleburgh et al. and Peel et al..

Figure 2. Sampling intensity per month, by country.

Red represents high sampling intensity and the numbers of samples collected per month is recorded within each grid cell. Records in the database with unknown collection date are not represented here (nine from Annobón, seven from Bioko, 14 from Príncipe, 10 from Rio Muni and 13 from São Tomé).

Figure 3. Histological sections of upper canine teeth from E. helvum for cementum age analysis (Giemsa stain).

Photographs and captions courtesy of Gary Matson, Matson’s Laboratory, MT, USA. Each age estimation was scored with a certainty code: A: highest certainty of reported age, B: histological evidence supported a given age result±0.5–1.5 years, or C: tooth or section quality was too compromised to accurately age. (a) Bat ID 424. Cementum age 2, certainty code A. 100X. The tooth was in excellent histological condition, as indicated by the presence of periodontal membrane and good differential staining between annuli and light cementum. (b) Bat ID 62. Cementum age 6, certainty code A. 100X. Annuli are complex, with at least two components each year. A key feature of age analysis is resolving uncertainty about whether complex annuli or individual components are being used as age indicators. (c) Bat ID 44. Cementum age 13, certainty code B (13–15 yrs). 400X. The root tip of this tooth had been broken off during extraction. Missing cementum complicates age analysis, reducing the evidence available for evaluating whether annuli observed at one point may be clearly identifiable as components of complex annuli at another point.

Figure 4. Correlation between ln(MFI) values pre- and post-repair of the Luminex machine used to run the assays, based on 293 samples.

The linear regression line is in red. (R²0.81, F-statistic: 1306 (1, 296), P<2.2e–16).