Assessing host–parasite specificity through coprological analysis: a case study with species of Corynosoma (Acanthocephala: Polymorphidae) from marine mammals

Abstract

In this paper we report an investigation of the utility of coprological analysis as an alternative technique to study parasite specificity whenever host sampling is problematic; acanthocephalans from marine mammals were used as a model. A total of 252 scats from the South American sea lion, Otaria flavescens, and rectal faeces from 43 franciscanas, Pontoporia blainvillei, from Buenos Aires Province, were examined for acanthocephalans. Specimens of two species, i.e. Corynosoma australe and C. cetaceum, were collected from both host species. In sea lions, 78 out of 145 (37.9%) females of C. australe were gravid and the sex ratio was strongly female-biased. However, none of the 168 females of C. cetaceum collected was gravid and the sex ratio was not female-biased. Conversely, in franciscanas, 14 out of 17 (82.4%) females of C. cetaceum were gravid, but none of 139 females of C. australe was, and the sex ratio of C. cetaceum, but not that of C. australe, was female-biased. In putative non-hosts, the size of worms was similar to that from specimens collected from prey. Results suggest that both acanthocephalans contact sea lions and franciscanas regularly. However, C. australe and C. cetaceum cannot apparently reproduce, nor even grow, in franciscanas and sea lions, respectively. Coprological analysis may represent a useful supplementary method to investigate parasite specificity, particularly when host carcasses are difficult to obtain.

Intestinal helminth fauna of the South American sea lion Otaria flavescens and fur seal Arctocephalus australis from northern Patagonia, Argentina

“…Unfortunately, information about the reproductive status of helminths is frequently lacking from parasitological surveys of otariids, or it is merely assumed that any parasite found in a host is part of their helminth fauna (see references in table 4). However, data from our study highlight the quantitative difference of including or excluding parasites obtained from non-hosts (see Aznar et al, 2012). We urge researchers to always provide appropriate information on maturity status of the parasites, if they are to be informative for parascript studies (e.g.…”

Gastrointestinal Parasites and Bacteria in Free-Living South American Sea Lions (Otaria flavescens) in Chilean Comau Fjord and New Host Record of a Diphyllobothrium scoticum-Like Cestode

“…South American sea lions (Otaria flavescens) belonging to family Otariidae are common carnivorous pinnipeds living along Eastern and Western coasts of South America. They are endemic in Argentina, Peru, South Brazil, and Chile (Vaz-Ferreira, 1982;Crespo, 1988;Túnez et al, 2008;Aznar et al, 2012;Hernández-Orts et al, 2013;Pereira et al, 2013). Along Chilean coastal shores, including Southern and Northern Patagonian fjords (Haussermann et al, 2014), more than 200 colonies of free-living South American sea lions were described.…”

GASTROINTESTINAL HELMINTHS OF THE FRANCISCANA Pontoporia blainvillei (MAMMALIA: CETARTIODACTYLA) IN THE NORTHERN COAST OF RIO GRANDE DO SUL STATE, SOUTHERN BRAZIL

“…All parasites were fixed and stained according to Amato et al (1991). Species identifications were based on taxonomic keys and specific descriptions (e.g., Yamaguti 1958, 1961, 1963, Foreyt 2005, Marigo et al 2008, Aznar et al 2012.…”