Uncinaria hamiltoni (Nematoda: Ancylostomatidae) in South American Sea Lions, Otaria flavescens, From Northern Patagonia, Argentina

Abstract

Thirty-one South American sea lion pups (Otaria flavescens) found dead in Punta León, Argentina, during the summer of 2002, were examined for hookworms (Uncinaria hamiltoni). Parasite parameters were analyzed in 2 locations of the rookery, i.e., a traditional, well-structured breeding area and an expanding area with juveniles and a lax social structure. Prevalence of hookworms was 50% in both localities, and no difference was observed in prevalence between pup sexes (P Ͼ 0.05). Hookworms were concentrated in the small intestine. Transmammary transmission is assumed because only adult hookworms were found in the pups. The mean intensity of hookworms per pup was 135; the mean intensity in females (92.78) was significantly different (P Ͻ 0.05) from that of males (230.25). No difference (P Ͼ 0.05) in intensity was found between the 2 breeding areas, although prevalence was higher in the traditional breeding area than in the other area. Location was the only factor affecting hookworm prevalence (P log-linear model: 0.9552; 2 : 1.5629). No apparent trend between body condition and intensity of hookworms was observed.South American sea lions, Otaria flavescens, occur in more than 85 rookeries and 'haul-outs' along the coast of Argentina in the southwestern Atlantic ocean, both on the midland and on islands, through the whole year (Reyes et al

Epidemiology of hookworm (Uncinaria spp.) infection in New Zealand (Hooker’s) sea lion (Phocarctos hookeri) pups on Enderby Island, Auckland Islands (New Zealand) during the breeding seasons from 1999/2000 to 2004/2005

“…All hookworms appeared to be of a similar size and were apparently reaching patency at about the end of P1 indicating a highly synchronised time of infection. (Sepúlveda and Alcaíno 1993), Lyons et al (2000a), and(Berón-Vera et al 2004) observed a similar tight profile of developmental stage that they suggested was supportive of the hypothesis of transmammary infection. Another argument in favour of this hypothesis was that faeces of pups treated once with an anthelmintic drug at birth were negative until the end of the study.…”

“…In the latter studies, pups in good body condition had more hookworms in their intestines than those in poor body condition. Assuming that transmammary transmission is the only way for pups to become infected and that hookworm burden is proportional to the quantity of milk ingested soon after birth, it is then reasonable to assume that pups in good body condition will have received more milk and, therefore, a greater amount of infective larvae (Lyons et al 1997(Lyons et al , 2001Berón-Vera et al 2004). Although there were significantly more males directly killed by hookworm infection than females, the burden in NZSL pups did not vary between sexes.…”

First report and characterization of adult Uncinaria spp. in New Zealand Sea Lion (Phocarctos hookeri) pups from the Auckland Islands, New Zealand

“…from NZSL were similar to those from Berón-Vera et al (2004), but were reduced relative to U. lucasi and U. hamiltoni as described by Baylis (1933Baylis ( , 1947. Almost all variables measured in hookworms from the southern hemisphere (Botto and Mañé-Garzón 1975;Berón-Vera et al 2004) present a broad range with regard to measurements important for comparing species: buccal capsule length, esophagus length, distance of vulva to posterior end, spicule length, and egg dimensions (Table 1). Disparity in the size of mature hookworms within the same host was observed during the present study.…”

“…from NZSL pups, U. hamiltoni from Otaria byronia(Baylis 1933), U. lucasi from C. ursinus(Baylis 1947) and U. hamiltoni from Otaria flavescens(Berón-Vera et al 2004) …”

Molecular systematics of pinniped hookworms (Nematoda: Uncinaria): species delimitation, host associations and host-induced morphometric variation

“…Despite these reports, there have been no comprehensive systematic studies of hookworms from pinnipeds. Literature reports have either diagnosed hookworms as Uncinaria sp., assigned specimens to one of the two described species (Berón-Vera et al, 2004), or noted that specimens do not fit the description of known species (Dailey and Hill, 1970;Castinel et al, 2006). This potential underestimation of species diversity has led to the suggestion of broad host ranges for U. lucasi and U. hamiltoni.…”