Stomach nematodes of three sympatric species of anatid birds off the coast of Patagonia

Abstract

The present study focuses on the nematode community in the stomachs of three sympatric anatid bird species from the Central Patagonian coast, Argentina. The bird species include the Chubut steamer duck, Tachyeres leucocephalus, the crested duck, Lophonetta specularioides, and the black-necked swan, Cygnus melancoryphus. Up to 138 nematodes representing five species were recovered from 10 of the 13 ducks examined, with an overall prevalence of 77% and a mean intensity of 13.8. Nematodes isolated from the gizzard were Streptocara formosensis and Sciadiocara legendrei (Acuariidae) in T. leucocephalus, and Epomidiostomum vogelsangi (Amidostomatidae) in C. melancoryphus, whereas Echinuria uncinata (Acuariidae) and Tetrameres (Petrowimeres) fissispina (Tetrameriidae) were found in the proventiculus of L. specularioides. In particular, S. legendrei was registered for the first time in South America and T. leucocephalus, whereas T. fissispina represents a new record in Argentina and L. specularioides. Moreover, E. vogelsangi and E. uncinata were isolated in Patagonia for the first time. The birds studied herein are sympatric in their distribution, and two of them are syntopic breeders; however, they were infected with different parasite species. This situation could be partially due to their diet or their seasonal movements, or a combination of both. Despite the low number of hosts examined, this work enhances our knowledge about parasites from a frequently occurring group of birds on the Patagonian coast, a subject that has not been studied extensively in South America.

Gastrointestinal helminths and related histopathological lesions in black-necked swans Cygnus melancoryphus from the Carlos Anwandter Nature Sanctuary, Southern Chile

“…As was noted in previous studies E. vogelsangi is a parasite from the gizzard (GONZÁLEZ-ACUÑA et al, 2010;AGÜERO et al, 2016;VALENZUELA et al, 2018), both under the koilin layer of the gastric pads, as well as in the muscle wall. In South America, this parasite seems to be restricted to the black-necked swan, reported in Argentina, Brazil (MCDONALD, 1969;FEDYNICH & THOMAS, 2008;AGÜERO et al, 2016), and Chile (GONZÁLEZ-ACUÑA et al, 2010;VALENZUELA et al, 2018). Present study is the first to provide information about pathology caused by this parasite.…”

“…Tetrameres (P.) fissipina has been reported in Cygnus buccinator Richardson, 1831, Cygnus columbianus Ord, 1815, and Cygnus cygnus Linnaeus, 1758 from Asia and North America (MACNEILL, 1970;YOSHINO et al, 2009). Previous reports in Neotropical waterfowl include Anas platyrhynchos, Cairina moschata Linnaeus, 1758, and Lophonetta specularioides King, 1828 from Argentina and Brazil (VICENTE et al, 1995;AGÜERO et al, 2016). Meanwhile, for C. melancoryphus has been isolated once from an unknown location (GONZÁLEZ-ACUÑA et al, 2010).…”

“…For the black-necked swan, Pfeiffer (1960) isolated R. bulbocirrosus from captive birds in Austria; nevertheless, the author specified that the birds died soon after their arrival from Argentina. The reduced records for both genera could reflect the limited parasitological studies on Neotropical waterfowl (AGÜERO et al, 2016).…”

“…However, none of these studies contemplated adopting a histopathological approach related to parasites. According to Agüero et al (2016), in the Neotropical region, the panoramic landscape is very similar, with waterfowl being the less frequently studied group of birds in terms of parasitic fauna. Consequently, it is indispensable to report the presence and describe the histopathological changes caused by parasites, which could be the consequence of a normal response or an impairment of the homeostatic mechanisms of the host (WOBESER, 2008).…”

Helmintofauna del cisne de cuello negro Cygnus melancoryphus (Aves: Anatidae) del Santuario de la Naturaleza Carlos Anwandter, Valdivia, Chile

“…Epomidiostomum vogelsangi es un nemátodo caracterizado por la presencia de hombreras o "epaulets" en el extremo anterior; los machos poseen un par de espículas divididas en 3 puntas en su extremo caudal; mientras que las hembras poseen un extremo posterior digitiforme (Anderson et al, 1989;Cram, 1927;Seurat, 1918). Este parásito fue reportado previamente en C. melancoryphus de Argentina y Brasil (Agüero et al, 2016;Fedynich y Thomas, 2008) Travassos, 1915 en Brasil, respectivamente, ambas parasitando el intestino delgado. En el presente to swans.…”