Pentastomids of wild snakes in the Australian tropics.

Crystal Kelehear,Denis O’Meally,David M Spratt,Richard Shine

doi:10.1016/j.ijppaw.2013.12.003

Abstract

Pentastomids are endoparasites of the respiratory system of vertebrates, maturing primarily in carnivorous reptiles. Adult and larval pentastomids can cause severe pathology resulting in the death of their intermediate and definitive hosts. The study of pentastomids is a neglected field, impaired by risk of zoonoses, difficulties in species identification, and life cycle complexities. We surveyed wild snakes in the tropics of Australia to clarify which host species possess these parasites, and then sought to identify these pentastomids using a combination of morphological and molecular techniques. We detected pentastomid infections in 59% of the 81 snakes surveyed. The ubiquity of pentastomid infections in snakes of the Australian tropics sampled in this study is alarmingly high considering the often-adverse consequences of infection and the recognized zoonotic potential of these parasites. The pentastomids were of the genera Raillietiella and Waddycephalus and infected a range of host taxa, encompassing seven snake species from three snake families. All seven snake species represent new host records for pentastomids of the genera Raillietiella and/or Waddycephalus. The arboreal colubrid Dendrelaphis punctulatus and the terrestrial elapid Demansia vestigiata had particularly high infection prevalences (79% and 100% infected, respectively). Raillietiella orientalis infected 38% of the snakes surveyed, especially frog-eating species, implying a frog intermediate host for this parasite. Raillietiella orientalis was previously known only from Asian snakes and has invaded Australia via an unknown pathway. Our molecular data indicated that five species of Waddycephalus infect 28% of snakes in the surveyed area. Our morphological data indicate that features of pentastomid anatomy previously utilised to identify species of the genus Waddycephalus are unreliable for distinguishing species, highlighting the need for additional taxonomic work on this genus.

Highlights

Pentastomids are long-lived endoparasites of the respiratory system of vertebrates, and are arguably the oldest metazoan parasites known to science
Pentastomiasis is most commonly caused by Linguatula serrata or Armillifer armillatus (Paré, 2008); these parasites may be transmitted via food or water contaminated with their eggs, or in the case of A. armillatus, via consumption of undercooked snake flesh (e.g., Yapo Ette et al, 2003; Lai et al, 2010; Ibinaiye et al, 2011; Hardi et al, 2013)
Demansia species were distinguished by ventral scale counts following the procedure outlined in Dowling (1951); specimens with 6197 ventral scales were identified as D. vestigiata and those with P198 ventral scales were identified as Demansia papuensis

Summary

Introduction

Pentastomids are long-lived endoparasites of the respiratory system of vertebrates, and are arguably the oldest metazoan parasites known to science. Pentastomids generally have an indirect life cycle, utilising at least one intermediate host; suitable intermediate hosts for pentastomids span diverse taxa (e.g., mammals, reptiles, insects, fish, and amphibians) but for most species the intermediate host is unknown (Riley, 1986; Paré, 2008). Larval pentastomids enter their definitive host when it consumes an infected intermediate host.

Methods

Results

Conclusion