High mortality associated with tapeworm parasitism in geladas (Theropithecus gelada) in the Simien Mountains National Park, Ethiopia

Abstract

Despite increasing appreciation for parasitism as an important component of primate ecology and evolution, surprisingly few studies have demonstrated the costs of helminth parasitism in primates. Detecting parasite-related costs in primates is particularly difficult because it requires detailed, long-term data on individual host reproductive success, survival, and parasitism. The identification of the larval tapeworm Taenia serialis in geladas under intensive long-term study in the Ethiopian Highlands (Nguyen et al. [2015] American Journal of Primatology, 77:579-594; Schneider-Crease et al. [2013] Veterinary Parasitology 198:240-243) provides an opportunity to examine how an endemic parasite impacts host reproductive success and survival. We used survival analyses to assess the mortality risk associated with protuberant larval cysts characteristic of T. serialis using a decade of data from a gelada population in the Simien Mountains National Park (SMNP), Ethiopia. We demonstrated strikingly high mortality associated with T. serialis cysts in adult females, particularly for younger adults. The estimated effect of cysts on male mortality was similar, although the effect was not statistically significant, likely owing to the smaller sample size. Additionally, the offspring of mothers with cysts experienced increased mortality, which was driven almost entirely by maternal death. Mothers with cysts had such high mortality that they rarely completed an interbirth interval. Comparison with a study of this parasite in another gelada population on the Guassa Plateau (Nguyen et al. [2015] American Journal of Primatology, 77:579-594) revealed lower cyst prevalence in the SMNP and similar cyst-associated mortality. However, many more females with cysts completed interbirth intervals at Guassa than in the SMNP, suggesting that T. serialis cysts may kill hosts more rapidly in the SMNP. Our results point toward the underlying causes of individual and population-level heterogeneity in T. serialis-associated mortality as important areas for future research.

Multi-scale predictors of parasite risk in wild male savanna baboons (Papio cynocephalus)

“…Helminth parasites can have major consequences for host fitness and health, by reducing host fecundity (e.g., Budischak et al 2017;Akinyi 2019), decreasing survival (e.g., Schneider-Crease et al 2017), and increasing susceptibility to infection by other parasites (e.g., Ezenwa et al 2010). These costs are especially important in the context of male behavior and life histories because male reproductive effort should have major consequences for individual infection risk (Lee 2006).…”

Phylogeography, mitochondrial DNA diversity, and demographic history of geladas (Theropithecus gelada)

“…Currently, two extant subspecies are recognized within Theropithecus gelada–Theropithecus gelada gelada Rüppell, 1835 and Theropithecus gelada obscurus , Heuglin, 1863, but their validity and geographic distributions are unclear [ 18 – 24 ]. Although geladas have been the subjects of several, intensive behavioural studies (e.g., [ 25 – 27 ]), their intra-specific phylogenetic relationships remain unresolved [ 28 – 30 ]. According to IUCN, T .…”

Severe coenurosis caused by larvae of Taenia serialis in an olive baboon (Papio anubis) in Benin

“…Moreover, as the dogs seem to be the primary source of infection for intermediate hosts, we highlight the importance of controlling the access of dogs in the recuse centers, as larval T. serials can seriously impact the health and welfare of primates. Dunbar (1980) and Schneider-Crease et al (2017a) have shown that the parasitism with larval T. serialis is an important cause of adult and infant mortality in wild geladas. Nguyen et al (2015) demonstrated also a decreased reproductive success in wild geladas infected with larvae of T. serialis .…”

“…The prevalence in a gelada population from Ethiopia varied according to the age group from 3.2 to 24.1%, with adults being more commonly affected (Dunbar, 1980). In another study, the overall prevalence was 14%, with adults and females more commonly affected than young and males, respectively (Schneider-Crease et al, 2017a). The overall average prevalence (evaluated as “visible swellings”) in the gelada population was 9.8% and 10.6%, in two studies performed in two different seasons (Dunbar, 1980).…”