This thesis reports on cross-sectional surveys aimed at detecting and characterizing haemoprotozoan parasites infecting wild free-ranging non human primates (NHPs) in Kenya, East Africa. Blood samples from olive baboons (Papio cynocephalus anubis), vervet monkeys or African green monkeys (AGMs, Chlorocebus aethiops) and Syke's monkeys (Cercopithecus mitis) from five provinces of Kenya were analyzed. The haemoprotozoan parasites survey was performed with microscopic evaluation of blood smears, serological techniques and molecular tools. Blood specimens and serum samples from 121 NHPs were tested for the presence of Trypanosoma brucei (Study I). Indirect antibody enzyme-linked immunosorbent assay (Ab-ELISA) detected titers of anti-T. brucei antibodies in 19% (23/121) of the sera sampled. Subsequent field-oriented latex agglutination test (LAT) detected presence of T. brucei antigens in 16% (19/121) of the sera. However, there were no active infections detected on fixed blood smears, or wet blood films. Of the 378 NHPs sera samples tested for Leishmania major exposure using Ab-ELISA, 66% had detectable anti-L. major antibodies (study II). Western blot (WB) assay detected anti-L. major antibodies in sera from 46% (175/378) of the NHPs samples. Specific proliferation of peripheral blood mononuclear cells to L. major antigen was demonstrated in 23% (17/57) of AGMs samples. Haemoprotozoan parasites, Entopolypoides macaci and Hepatocystis kochi were detected by microscopic evaluation of Giemsa-stained blood smears from 179 NHPs (study III). The prevalence rate of E. macaci was 43% in African green monkeys, 35% in Syke’s monkeys and 33% in baboons. H. kochi infection rate was 18% in African green monkeys, 23% in baboons and 25% in Syke’s monkeys. Subsequent indirect immunofluorescent antibody test (IFAT) supported the morphologic appearance of E. macaci observed by microscopy. Molecular tools were used to detect and identify haemoprotozoan parasites in wild free-ranging NHPs (study IV). Nested polymerase chain reaction (PCR) targeting Babesia β-tubulin gene detected a 22% (27/125) B. microti infections in free-ranging NHPs in Kenya. PCR also detected 22% mixed infections by Hepatocystis and Entopolypoides, 12% Hepatocystis and Babesia and 7% Entopolypoides and Babesia (study V). Phylogenetic analysis inferred from mitochondrial cytochrome b (Cyt-b) gene confirmed the presence of Hepatocystis kochi whereas analysis of 18SS rRNA gene confirmed presence of two piroplasms, Babesia sp. and Entopolypoides macaci. In conclusion, epidemiological results from sero-prevalence studies provide strong circumstantial evidence that some species of Kenyan NHPs are naturally exposed to L. major and T. brucei infections and could be potential reservoir hosts for these haemoparasites. Molecular diagnosis revealed the occurrence of mixed parasite infections and confirmed the circulation of Babesia and Entopolypoides species in the same populations of Kenyan NHPs.

Most organisms are rarely infected with just a single species of parasite and are usually simultaneously infected with a range of species. Thus, the parasite fauna of a host represents an entire community composed of multiple individuals from many different species. In nature, it is within the host that parasites can encounter conspecifics and individuals from other species. As in any ecosystem, while such interactions between parasites can be antagonistic due to competition or conflicting interests, association between different species can also be beneficial. In this thesis, I investigated patterns of associations between parasites in the New Zealand cockle Austrovenus stutchburyi through a combination of descriptive and experimental studies employing both standard ecological field techniques and molecular biology methods. It was found that the presence and infection intensity of various parasites species are not independent of each other. Among cockles, an association was found between two trematode taxa, i.e. between the infection intensity by foot-encysting echinostomes and the metacercariae of Gymnophallus sp. It was also found that the presence of the parasitic copepod Pseudomyicola spinosus was associated with greater infection intensity by the echinostomes but not Gymnophallus sp. While it was postulated that the positive association between the echinostomes and Gymnophallus sp. was due to the latter�s preference to infect cockles that are stranded on the sediment surface as a result of heavy echinostome metacercariae burden in their foot, a field experiment found that Gymnophallus cercariae did not preferentially infect cockles that have been forced to remain above the sediment surface as opposed to those that were forced to remain buried. Meanwhile, the two species of echinostomes known to encyst in the cockle�s foot, Acanthoparyphium sp. and Curtuteria australis, were found to represent cryptic species complexes. The presence of such cryptic species means that it is possible that some potential interspecific interactions are overlooked. A study of the population structure of Gymnophallus sp. found that each cockle contains multiple genetically distinct individuals and that clonal individuals rarely co-occur in the same cockle. This adds to the growing body of evidence suggesting that in addition to acting as a means of reaching the definitive host, the second intermediate host also acts to promote genetic diversity by accumulating cercariae shed by multiple first intermediate hosts in the environment. An experimental infection study conducted with Curtuteria australis cercariae deriving from singly-infected first intermediate hosts revealed that different clonal lineages varied with respect to their contribution to host manipulation. It was found that while certain lineages have a preference for host manipulation, others tend to adopt a "hitch-hiker"-type life history strategy. However, this genetic predisposition was also found to be a phenotypically plastic trait, as the presence of a higher number of manipulators seems to encourage newly-arrived cercariae to become manipulators, regardless of clonal lineage. This thesis provides evidence that patterns of interactions can affect various aspects of parasite life history. Apart from host condition, parasites can also be affected by other parasites. Studying the dynamics of mixed infections can provide informative insights for evolutionary and ecological research.

Bibliography: leaves 218-251 / xviii, [ca. 100] leaves : ill ; 31 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Microbiology and Immunology, 1983

Includes bibliography / vi, 153 [i.e. ca. 300] leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, 1985

Includes bibliographical references. (p. 131-140) / 140 leaves : ill. (some col.) ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1968

Mucins play important roles in host-pathogen interactions, influencing host resistance, establishment of infection, as pathogen recognition sites and a source of nutrients. They are highly glycosylated molecules and changes in monosaccharide composition during parasitism have been reported. Effects of parasites on monosaccharide component of fundic and duodenal mucins of sheep were investigated in 3 age ranges (i) 4-4.5, (ii) 6 and (iii) 8-9 months old: (1) noninfected; (2) infected with 10,000 Haemonchus contortus and euthanased 21 days post infection (p.i.); (3) infected with 50,000 Teladorsagia circumcincta and euthanased 28 days p.i. Three days-old lambs and 9 weeks-old lambs: (a) milk-fed, (b) solid-fed and (c) solid-fed, infected with T. circumcincta were also included. The effects of H. contortus and T. circumcincta infection in mucin changes were significantly different in the fundus, however, both of them shared some similarities. Infected sheep showed lower proportion of fucose and sialic acids in fundic and duodenal mucins compared with non-infected animals, the level of sulphation varied depending on the age of infected sheep: decrease in young sheep but increase in older animals. H. contortus infection also caused increased proportions of GlcNAc and Gal in fundic mucins and duodenal mucins respectively at all ages, however, in T. circumcincta infection, it was shown that the alterations of mucins were age-dependent. T. circumcincta infected sheep showed the significant changes at young ages (4-6 months-old) while 8-9 months-old animals showed less change in fundic mucins compared with non-infected animals. Effects of H. contortus and T. circumcincta infection differed in the fundic mucins but were similar in the duodenum. The study showed that parasitism caused the modifications of monosaccharide composition in gastrointestinal mucins of sheep. These alterations may result from parasite species differences, causing different effects from the host’s immune response. The changes in mucin profiles observed in the duodenum of sheep infected with abomasal nematodes suggested that the host may respond to parasitism. This would facilitate the use of mucins from accessible sources, without euthanasing the animals, to investigate the changes in mucin compositions which can be used to diagnose the susceptibility or resistance of sheep to parasites

The reproductive strategies of four intertidal grapsid crabs, Hemigrapsus sexdentatus, H. crenulatus, Cyclograpsus lavauxi, and Helice cressa, were studied in the field and laboratory, with emphasis on mating behaviour, duration of female receptivity, and sperm competition. Mating occurred in all species during the intermoult on the days prior to oviposition, when the gonoporo opercula of females became temporarily mobile. Female Helice crassa mated up to three weeks after oviposition, but in all other species mating typically ceased at egg-laying. Male Hemigrapsus pp. used a female-centered competition strategy in which they searched for and defended receptive females until they laid eggs. In contrast, male C. lavauxi searched for and intercepted receptive females only for the duration of copulation and then pursued other receptive females (a mating system termed encounter rate competition with pure search and interception). Male Helice crassa searched for receptive females in their immediate neighbourhood and mated with them briefly on the substrate or in the burrow after which the female left (a mating system termed encounter rate competition with neighbourhoods of dominance). The mating season was short and highly synchronous for Hemigrapsus exdentatus and Cyclograpsus lavauxi and asynchronous for Hemigrapsus crenulatus and Helice crassa. In the laboratory, the mean duration of receptivity for females housed with three males varied between 4.1 and 12.4 days, and the copulation frequency of females varied before oviposition between 2.1 and 24.3 times (mean) depending on the species. Female Hemigrapsus spp. isolated from males stayed receptive significantly longer than females held continuously with males. This suggests that females are able to control the duration of their receptivity, and therefore the time available for mating, according to the absence or presence of males. The operational sex ratio (OSR) had no effect on the duration of female receptivity, but female Hemigrapsus crenulatus mated more often when several males were competing for access. Therefore, male-male competition increased the number of matings per female and hence sperm competition within the female spermathecae. Larger males mated significantly more often than smaller males in all species. However, male size did not affect ejaculate size, meaning that small and large males transferred similar-sized ejaculates, e.g., in Hemigrapsus spp. Males of the two Hemigrapsus species followed a different strategy of sperm allocation. Male H. crenulatus, which are typically confronted with a high mating frequency of the female and a long, asynchronous mating season, distributed similar-sized ejaculates, irrespective of female size. By contrast, male H. sexdentatus, which experience a comparatively lower risk of sperm competition during a short, synchronised mating season, invested larger ejaculates for larger females than for smaller females. In addition, the size of the first and second ejaculates transferred to a female by a male H. crenulatus were not significantly different, whereas the first was larger than the second for H. sexdentatus. A parasitological survey was undertaken of the four grapsid crabs and the presence, seasonal variation and relationship with host gender and size of parasites determined. Four internal parasites were discovered: Nectonema zealandica n. Sp. (Nematomorpha: Nectonematoidea), portunion sp. (Isopoda: Entoniscidae), Profilicollis novaezelandensis n. sp. and profilicollis antarcticus (Acanthocephala: P olymorphidae). Portunion sp. castrated its female hosts, but not the males thereby creating a more male-biased sex ratio. Males parasitised with portunion sp. were equally successful during male-male competition and the number of matings they achieved. The above findings are important for our current understanding of mating strategies in Grapsidae, which are more diverse than previously thought. Females with a restricted duration of sexual receptivity have some control over their receptive period and can therefore influence the OSR and the extent of male-male competition. As females mated multiple times during their receptive period, sperm competition is a common feature in Grapsidae. However, males employed different tactics in regards to sperm competition such as longer mating duration (e.g., C. lavauxi), high number of matings (Helice crassa), or post-copulatory mate guarding until oviposition (Hemigrapsus spp.).

A survey of gastro-intestinal parasites was conducted on faecal samples collected from 379 feral cats and 851 native fauna from 16 locations throughout Western Australia. The prevalence of each parasite species detected varied depending upon the sampling location. Common helminth parasites detected in feral cats included Ancylostoma spp. (29.8%), Oncicola pomatostomi (25.6%), Spirometra erinaceieuropaei (14%), Taenia taeniaeformis (4.7%), Physaloptera praeputialis (3.7%) and Toxocara cati (2.6%). The most common protozoan parasites detected in feral cats were Isospora rivolta (16.9%) and I. felis (4.5%). The native mammals were predominately infected with unidentified nematodes of the order Strongylida (59.1%), with members of the orders Rhabditida, Spirurida and Oxyurida also common. Oxyuroid nematodes were most common in the rodents (47.9%) and western grey kangaroos (27.8%). Several species of Eimeria were detected in the marsupials whilst unidentified species of Entamoeba and coccidia were common in most of the native fauna. Primers anchored in the first and second internal transcribed spacers (ITS1 and ITS2) of the ribosomal DNA (rDNA) were used to develop a polymerase chain reaction-linked restriction fragment length polymorphism (PCR-RFLP) technique to differentiate the species of Ancylostoma detected in feral cats. Amplification of the ITS+ region (ITS1, ITS2 and 5.8S gene) followed by digestion with the endonuclease RsaI produced characteristic patterns for A. tubaeforme, A. ceylanicum and A. caninum, which were detected in 26.6%, 4.7% and 0% of feral cats respectively. Giardia was detected in a cat, dingo, quenda and two native rodents. Sequence analysis at the small subunit rDNA gene (SSU-rDNA) identified the cat and dingo as harbouring G.duodenalis infections belonging to the genetic assemblages A and D respectively. Subsequent analysis of the SSU-rDNA and elongation factor 1 alpha (ef1á) identified a novel species of Giardia occurring in the quenda. Attempts to genetically characterise the Giardia in the two native rodents were unsuccessful. Serological detection of Toxoplasma gondii was compared to a one tube hemi-nested PCR protocol to evaluate its sensitivity. PCR was comparable to serology in detecting T. gondii infections, although PCR was a much more definitive and robust technique than serology for large numbers of samples. Amplification of T. gondii DNA detected infections in 4.9% of feral cats and 6.5% of native mammals. The distribution of T. gondii does not appear to be restricted by environmental factors, which implies that vertical transmission is important for the persistence of T. gondii infections in Western Australia. These results demonstrate that cats carry a wide range of parasitic organisms, many of which may influence the survival and reproduction of native mammals. As such, the large-scale conservation and reintroduction of native fauna in Western Australia must not disregard the potential influence parasites can have on these populations.

Thesis (M.S.)--Michigan State University. Dept. of Fisheries and Wildlife, 2008. / Title from PDF t.p. (viewed on July 30, 2009) Includes bibliographical references (p. 176-183). Also issued in print.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.