Investigation of hookworm (Uncinaria sp.) parasites in free-ranging Australian fur seals (Arctocephalus pusillus doriferus)

• Main Author: Ramos, Paul W.
• Format: Master Thesis
• Language: English
• Published: 2013
• Subjects: Arctocephalus pusillus doriferu; Uncinaria sp; hookworm; Australian fur seal; New Zealand; Ramos; Antarc*; Antarctica; Elephant Seal; Mirounga leonina; Southern Elephant Seal; Callorhinus ursinus
• Online Access: http://hdl.handle.net/11343/38115

Deposited with permission of the author. © 2013 Paul W. Ramos This study investigated the presence, prevalence, intensity and duration of infection of Uncinaria sp. within populations of the Australian fur seal Arctocephalus pusillus doriferus (Schreber) located in Victorian waters off of southeastern Australia. All of the four seal colonies involved in this study, representing 77% of the population of A. p. doriferus, demonstrated low (2-18) intensity of hookworm infections in 58-96% of pups 4-8 weeks old, with prevalence of infection decreasing to 0% by 15-20 weeks of age. Higher (87-96%) prevalences were found in three of the four colonies, with the fourth colony having a lower (58%) prevalence as well as a mainly rocky rather than sandy substrate. The pathological impact could not be conclusively determined due to small sample sizes, but hookworm infection was not considered to play a significant role in pup morbidity and mortality. Hookworm infection did not have a statistically significant impact on haematological parameters (packed cell volume and total plasma protein) and no sex predilections with infection were found. Additionally, this study presents morphological and molecular data on hookworms from A. p. doriferus currently identified in Australian waters as Uncinaria hamiltoni Baylis, 1933. Additional specimens from the Australian sea lion Neophoca cinerea (Péron) and the New Zealand fur seal Arctocephalus forsteri (Lesson) from Australia, and the southern elephant seal Mirounga leonina (Linnaeus) from Antarctica, were included. Using the internal transcribed spacer (ITS), hookworms from A. p. doriferus, N. cinerea and A. forsteri were genetically similar to one another but were distinct from Uncinaria spp. found in M. leonina from Antarctica as well as from Zalophus californianus (Lesson) and Callorhinus ursinus (Linnaeus) from California. Few morphological differences were detected between these taxa.