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Biomedical subjects

M G O'Callaghan

Publications and source records attributed to M G O'Callaghan.

At least 19 recordsLinked to original sources
PubMed2003

Cysticercoids of five species of Raillietina Fuhrmann, 1920 (Cestoda: Davaineidae) in ants, Pheidole sp., from emu farms in Australia.

Cysticercoids of five species of Raillietina, R. australis (Krabbe, 1869) Fuhrmann, 1924, R. beveridgei O'Callaghan, Davies & Andrews, 2000, R. chiltoni O'Callaghan, Davies & Andrews, 2000, R. dromaius O'Callaghan, Davies & Andrews, 2000 and R. mitchelli O'Callaghan, Davies & Andrews, 2000, parasitic in the emu Dromaius novaehollandiae Latham, are described. Each species was identified on the basis of the number and size of the rostellar hooks, which correspond to those of adult worms. Cysticercoids were recovered from the haemocoele of the gaster of ants belonging to the genus Pheidole (Hymenoptera: Formicidae) in Australia. There was a trend towards an inverse relationship between the size of the cysticercoids and the parasite burden in the intermediate host.

Animals↗
PubMed2002

Variation among Merino sheep in susceptibilty to lice (Bovicola ovis) and association with susceptibility to trichostrongylid gastrointestinal parasites.

Sheep of two bloodlines of Merino were artificially infested with equal numbers of lice (Bovicola ovis) and the resulting louse populations were monitored over the following 20 months. The sheep were shorn 6 and 17 months after infestation and, for analysis, the louse counts considered in 3 years separated by shearings. Nematode faecal egg counts (FECs) were assessed on faecal samples collected on five occasions, three times following natural challenge and twice after artificial challenge with 40,000 trichostrongyloid larvae (84% Trichostrongylus vitrinus). In addition, blood samples were collected and measured for B. ovis-specific immunoglobulins (predominantly IgG), B. ovis-specific IgE and serum total IgE. Bloodlines differed significantly in the size of louse populations at the end of year 2, FEC after both natural and artificial challenge and in serum levels of all three antibodies (p<0.05). There were also large variations in louse counts and FEC among sheep within bloodlines. Louse counts at inspections after louse populations had been allowed to build up were highly repeatable, both between and within years. However, correlations with counts at inspections soon after initial infestation and following shearing were lower. FEC after natural challenge was correlated with louse counts in year 2 (r=0.45, p<0.01) and year 3 (r=0.38, p<0.05), but the correlation with counts in year 1 was not significant (r=0.25, p>0.05). FEC following artificial challenge was significantly correlated with louse counts in year 3 (r=0.36, p<0.05), but not in year 2 (r=0.25, p>0.05) or year 1 (r=0.04, p>0.05). Louse counts in the 3 years were significantly correlated with anti-B. ovis antibody concentration (r=0.60, 0.48, 0.36), but not with levels of either anti-B. ovis or total serum IgE. These results suggest that sheep with greater resistance to gastrointestinal parasites also tend to be less susceptible to lice. Whether this is due to interaction of the effects of the parasites or to correlation in underlying resistance mechanisms requires clarification.

Animals↗
PubMed1998

Eimeria species in the Pearson Island Rock Wallaby, Petrogale lateralis pearsoni.

Four species of previously described Eimeria were identified from oocysts present in the faeces of Pearson Island rock wallabies, Petrogale lateralis pearsoni from Pearson Island, South Australia. Eimeria petrogale and Eimeria sharmani have been reported in P. lateralis; however, the presence of Eimeria godmani and Eimeria inornata expands the suite of eimerian species known in rock wallabies of the "lateralis" complex. These observations indicate that the host distribution of Eimeria species in rock wallabies is more diverse than previously thought, and supports the hypothesis that these coccidia have an ancient association with rock wallabies which persisted as the hosts radiated.

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PubMed1994

Lesions associated with infestation of a yellow-footed rock wallaby (Petrogale xanthopus xanthopus) with larvae of Odontacarus (Leogonius) adelaideae (Womersley) (Acarina: Trombiculidae) in South Australia.

Dermatitis associated with natural infestation of a yellow-footed rock wallaby (Petrogale xanthopus xanthopus) with larvae of the chigger mite, Odontacarus (Leogonius) adelaideae is described. This record extends the known host range of O. adelaideae and is the first from a native animal in southern Australia.

Animals↗
PubMed1992

The occurrence of Dirofilaria immitis in dogs in South Australia.

Heart, lung and samples of blood from 230 dogs were examined for infections of filarial parasites. Dirofilaria immitis worms and microfilariae were detected in one dog. Blood samples from a further 1428 dogs were examined for microfilariae and 22 were found to be infected. Eighteen dogs were infected with D immitis microfilariae and four with Dipetolonema reconditum microfilariae. The histories were available for 18 of the dogs infected with heartworm and only seven dogs had not travelled outside South Australia. It was concluded that heartworm infection was endemic in South Australia but the apparent prevalence was only about 1%.

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PubMed1989

Host-parasite associations of Eimeria spp. (Apicomplexa:Eimeriidae) in kangaroos and wallabies of the genus Macropus (Marsupialia:Macropodidae).

Faecal samples from 514 kangaroos and wallabies representing 12 species of the genus Macropus were examined for oocysts of Eimeria spp. Six species of Eimeria were redescribed from their type hosts, and on the basis of finding homologous oocysts in the faeces of other Macropus spp., host ranges for these coccidia were extended. Eimeria hestermani Mykytowycz, 1964 is redescribed from M. giganteus (eastern grey kangaroo) and is described from M. fuliginosus (western grey kangaroo), M. rufogriseus (red-necked wallaby), M. dorsalis (black-striped wallaby), and M. eugenii (tammar wallaby). E. toganmainensis Mykytowycz, 1964 is redescribed from M. rufus (red kangaroo) and the host range is extended to M. giganteus, M. fuliginosus, M. rufogriseus and M. eugenii. E. wilcanniensis Mykytowycz, 1964 is redescribed from M. rufus, and the host range is extended to M. giganteus, M. fuliginosus and M. robustus (euro or wallaroo). E. macropodis Wenyon & Scott, 1925 is redescribed from M. rufogriseus, and is described from M. giganteus, M. fuliginosus, M. rufus, M. irma (western brush wallaby), M. parryi (whip-tailed wallaby), M. dorsalis, M. eugenii, and M. parma (parma wallaby). E. fausti Yakimoff & Matschoulsky, 1936, E. cunnamullensis Mykytowycz, 1964 and E. purchasei Mykytowycz, 1964 are synonymized with E. macropodis. E. marsupialium Yakimoff & Matschoulsky, 1936 is redescribed from M. giganteus, and from M. fuliginosus. E. gungahlinensis Mykytowycz, 1964 is redescribed from M. fuliginosus, and from M. giganteus. Seven new species of Eimeria are described. E. flindersi, new species, is described from M. eugenii, M. rufogriseus, and M. antilopinus (antilopine wallaroo). E. prionotemni, new species, is described from M. eugenii, M. parryi, M. rufogriseus, M. agilis (agile wallaby) and M. dorsalis. E. mykytowyczi, new species, is described from M. agilis, M. antilopinus, and M. parryi. E. parryi, new species, is described from M. parryi. E. yathongensis, new species, is described from M. fuliginosus and M. giganteus. E. parma, new species, is described from M. parma, and E. desmaresti, new species, is described from M. rufogriseus. E. kogoni Mykytowycz, 1964, and E. rufusi Prasad, 1960 are considered species inquirendae. The host-parasite associations of these coccidia, and of similar species of Eimeria in other genera of Macropodoid marsupials, are discussed in relation to the postulated phylogeny of the hosts.

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PubMed1989

Coccidia of domestic and feral goats in South Australia.

Faecal samples were examined from 497 domestic and 318 feral goats in South Australia. Oocysts of Eimeria species were detected in 97% of the domestic goats and 3% of the feral goats. The species of Eimeria identified from domestic goats (and their prevalences) were E. hirci (82%), E. arloingi (81%), E. ninakohlyakimovae (51%), E. alijevi (49%), E. caprina (32%), E. christenseni (29%), E. caprovina (12%), E. jolchijevi (9%) and E. apsheronica (6%). Two of these species, E. caprina and E. jolchijevi, were not found in the feral goats. E. christenseni, E. caprovina and E. jolchijevi were more prevalent in domestic goats less than 12 months old than in adults.

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PubMed1987

Sarcocystis mucosa (Blanchard 1885) Labbé 1889 in unadorned rock wallabies (Petrogale assimilis) and Bennett's wallabies (Macropus rufogriseus).

Macroscopic cysts of a protozoan parasite were detected in the gastro-intestinal walls of two unadorned rock wallabies (Petrogale assimilis) and 20 Bennett's wallabies (Macropus rufogriseus). The cysts were located predominantly in the muscularis externa and the submucosa of the forestomach, small intestine and colon and sometimes in the muscularis externa of the oesophagus and caecum. All cysts exhibited similar morphological and ultrastructural characteristics. They were bounded by thick primary cyst walls (containing distinctive bulbous-like protrusions) and were surrounded by collagen fibres and host connective tissue cells (mainly fibrocytes). The cysts were divided by septae into internal compartments containing metrocytes and cystozoites. The cystozoites contained numerous organelles typical of apicomplexan protozoan parasites (including an apical complex, a micropore, rhoptries, micronemes, polysaccharide granules and 22 subpellicular microtubules) and they were observed to divide by the process of endodyogeny. Despite the unusual location of the cysts, they were classified on the basis of their ultrastructural characteristics as Sarcocystis mucosa (Blanchard 1885) Labbé 1889.

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