ABSTRACT The scarce information on the helminth fauna in otariids from the Southeastern Pacific comes mainly from stranded individuals or killed for that purpose. In this study, we compared the abundance and composition of enteroparasitic assemblages of Otaria flavescens using coprological techniques. Three sampling localities from north to south spanning 2,200 km off the Chilean coast were considered (Iquique, Viña del Mar, and Talcahuano). In all, 60 fecal samples were collected, and eggs belonging to 5 taxa were found in 91.6% of the samples. They were the anisakid nematodes Contracaecum and Pseudoterranova , the cestode Adenocephalus (syn. Diphyllobothrium ), the trematode Ogmogaster , and the acanthocephalan Corynosoma . Samples from southern Chile (Talcahuano) showed the highest prevalence. Adenocephalus eggs had the highest prevalence and abundance in Iquique and Talcahuano, whereas Ogmogaster was the less prevalent and abundant in all sampling localities. Corynosoma eggs had similar prevalence and abundance among sampling localities, and Pseudoterranova eggs were absent in Iquique and with median prevalence values in Viña del Mar and Talcahuano. Thus, the composition of parasite egg assemblages was different between sampling localities. These differences between sampling localities may help to explain differential records of some zoonotic parasitoses such as pseudoterranovosis and diphyllobothriosis in Peru and Chile, where consumption of raw or marinated fish (ceviche) is common. For example, the lower diversity of parasite egg assemblages in the northern Chilean coast may be due to the absence or lower abundance of first intermediate/paratenic hosts of Pseudoterranova .

ABSTRACT The relationship between a parasite and its host will have an energy cost for the host at some point; however, this basic hypothesis has seldom been evaluated. Using Emerita analoga as a model species, we investigated the aerobic metabolism, ammonia excretion rate, and locomotor performance patterns of crabs both uninfected and infected with the acanthocephalan Profilicollis altmani . Our results show that infected Emerita had a lower metabolic rate compared to uninfected ones. Whether or not this decrease is a result of the pathology of the parasite infection or due to manipulation of the host by the parasite is still unknown. We discuss the importance of using anaerobic and aerobic metabolism and more-complex scenarios in order to understand the effects on host fitness and not only on the immediate response of the host.

This study verifies the identity of adult specimens of the parasite Profilicollis chasmagnathi (Acanthocephala, Polymorphidae) recovered from kelp gulls Larus dominicanus (Aves, Laridae), and cystacanths found in crabs Cyrtograpsus altimanus (Crustacea, Decapoda) from the southwestern Atlantic coast. The life cycle of this parasite is elucidated in the intertidal zone of Patagonia, Argentina, based on morphological and molecular data. Preferences by size and sex of the intermediate host and seasonal variation of this parasite are provided, contributing to the knowledge of this host-parasite association.