1. Fifteen parasite species comprising the T. erytreae complex in Salisbury are listed. 2. Detailed, illustrated accounts are given of the biology of two primary parasites, Tetrastichus Pradiatus Waterston and Psyllaephagus pulvinatus (Waterston ), and their main hyperparasite, Aphidencyrtus cassatus Annecke. 3. The biology of the remaining twelve less important hyperparasites is briefly described and illustrated. 4. Keys are given to the adults, pupae and pupal remains of the parasites. 5 . The population fluctuations of T. erytreae and its parasites, as determined from field studies in the Salisbury area, are reported . 6. The interrelationships between T. erytreae and its parasites are summarised and discussed. Summary, p. 89.

Malaria remains a debilitating disease, especially in developing countries of the tropics and sub-tropics. Increasing drug resistance and the rising cost of drug development calls for methods that can cost-effectively identify new drugs. The proteins of the malaria causing Plasmodium parasites often exhibit unique features compared to their mammalian counterparts. Such features invite discovery of parasite-specific drugs. In this study computational methods were applied to understand unique structural features of enzymes from the Plasmodium polyamine biosynthesis pathways. Molecular modeling of P. falciparum arginase was used to explore the structural metal dependency between enzyme activity and trimer formation. This dependency is not observed in the mammalian host. A novel inter-monomer salt-bridge was discovered between Glu 295 and Arg 404 that helps mediate the structural metal dependency. Removal of the active site metal atoms promoted breaking of the Glu 295á::Arg 404b interaction during simulation. The involvement of this salt-bridge was further confirmed by site-directed mutagenesis of the recombinantly expressed enzyme and subsequent simulation of the mutants in silico. Mutations designed to break the salt-bridge resulted in decreased enzyme activity and oligomerisation. Furthermore, simulation of the mutants indicated potential loss of metal co-ordination within the active site. The interface around Glu 295á::Arg 404b could thus serve as a novel therapeutic target. In Plasmodium the usually separate activities S-adenosylmethionine decarboxylase and ornithine decarboxylase occur in a single bifunctional enzyme. Previous studies have established the importance of complex formation and protein-protein interactions for correct enzyme functioning. Disturbing these interactions within the complex may therefore have inhibitory potential. In the second aspect of this study the potential quarternary structure of AdoMetDC/ODC was studied by homology modeling of the domains followed by protein-protein docking. The results from five Plasmodium species suggest that one face of each domain is favoured for complex formation. The predicted faces concur with existing experimental results, suggesting the direct involvement of Plasmodium-specific inserts in maintaining complex formation. Further fine-grained analysis revealed potentially conserved residue pairs between AdoMetDC/ODC that can be targeted during experimental follow-up. In both aspects of this study computational methods yielded useful insights into the parasite-specific features of polyamine biosynthesis enzymes from Plasmodium. Exploitation of these features may lead to novel parasite-specific drugs. Furthermore, this study highlights the importance of simulation and computational methods in the current and future practice of Science. / Thesis (PhD)--University of Pretoria, 2010. / Biochemistry / unrestricted

This collection of papers comprises four sections. The first section deals with the helminth and arthropod parasites recovered from a variety of mammalian hosts, and consists of four chapters. The first chapter deals with the taxonomy of the parasites of mammalian hosts, where some 15 nematode species were either newly described, redescribed or descriptions amended, and the immature stages of an oestrid fly and the adults of two hippoboscid flies described. The second describes the seasonal occurrence of arthropod and helminth parasites recovered from approximately 1 380 antelope, scrub hares, warthogs and bushpigs. In the third chapter some miscellaneous natural and experimental findings of helminths in free-living hosts are presented, amongst others several new host-parasite associations and the proceedings of symposia, while the fourth chapter deals with the pathology of natural infections of impalas with Cooperiodes hepaticae, kudus with Elaeophora sagitta and buffaloes with Parafilaria bassoni. The second section deals with the parasites of freshwater fishes. In the taxonomic part of this section, Chapter 1, one trematode genus is redescribed, and one new trematode species and 14 new nematode species described. In the second chapter, the seasonal occurrence of the helminth parasites of approximately 700 freshwater fish representing 14 species is presented. The third part deals with the helminths of lizards, snakes and crocodiles, where a new Paraspirura species, a new Madathamugadia species and some 14 new species, subspecies and forms of subspecies of the oxyurid genera Spauligodon, Skrjabinodon, Thelandros and Tachygonetria were described. A comprehensive host-parasite list of snakes and lizards is included, as is an equally comprehensive host-parasite list of the pentastome parasites of crocodiles. In the fourth part, two new Tetrameres species are described and the population dynamics of guineafowls and Swainson’s spurfowl discussed. A complete list of the helminth parasites of guineafowls is listed, together with an extended host list of these parasites. / Thesis (PhD)--University of Pretoria, 2009. / Veterinary Tropical Diseases / unrestricted

Historical structuralism is presented as a research program in evolutionary biology. It uses patterns of common ancestry as initial hypotheses in explaining evolutionary history. Such patterns, represented by phylogenetic trees, or cladograms, are postulates of persistent ancestral traits. These traits are evidence of historical constraints on evolutionary change. Patterns and processes consistent with a cladogram are considered to be consistent with an initial hypothesis of historical constraint. As an application of historical structuralism, a phylogenetic analysis is presented for members of the digenean plagiorchioid genera Glypthelmins Stafford, 1905 and Haplometrana Lucker, 1931. The eight species studied are intestinal parasites of frogs and toads in North, Central, and South America. In a Wagner parsimony analysis of 21 morphological characters with both the PAUP and PHYSYS computer programs, a single phylogenetic tree with a consistency index of 84.8% can be inferred. This suggests strong historical constraint in the evolution of the characters examined. It is postulated that the eight species form a monophyletic group (clade), consisting of two less inclusive clades. Glypthelmins hyloreus and G. pennsylvaniensis comprise one of these clades; G. robustus, G. shastai, H. intestinalis, G. californiensis, G. quieta, and G. facioi comprise the other. G. robustus, found in Bufo marinus in Colombia, is both the southernmost and the most plesiomorphic member of its clade. Glypthelmins californiensis, G. quieta, and G. facioi form a clade, and parasitize frogs in the Rana pipiens complex in Mexico, eastern North America, and Central America, respectively. Glypthelmins shastai and H. intestinalis, the latter of which is the only member of its genus, form a western North American clade, and parasitize Bufo boreas and Rana pretiosa, respectively. The phylogenetic analysis includes a redescription of G. shastai, the synonymy of the genus Haplometrana with Glypthelmins, the redescription of H. intestinali s as G. intestinalis, an emended diagnosis of the genus Glypthelmins, and the first account of the life cycle of G. californiensis. Three aspects of phylogenetic analysis are examined in detail. These are the coding of multistate character trees, the use of parasite data to infer host relationships, and the properties of the Consistency Index and the F-Ratio. It is proposed that the Consistency Index be calculated without non-homoplasious autapomorphic characters. For the present study, this modification gives a value of 76.9%. Using the phylogenetic tree as a general reference system of patterns of common ancestry, it is inferred from developmental studies that (1) there is no conflict between the phylogenetic relationships indicated by only larval or only adult characters, and that (2) the evolution of some of the characters involved certain types of heterochrony. Paedomorphic heterochrony is inferred to have occurred in the evolution of the uterus in G. shastai, H. intestinalis, G. californiensis, G. quieta, and G. facioi. Peramorphic heterochrony is inferred to have occurred in the evolution of the penetration glands in G. facioi, and of the hindbody in H. intestinalis. The relatively longer hindbody of H. intestinalis was experimentally induced to show paedomorphic development by raising specimens of H. intestinalis in Bufo boreas, which is the host of G. shastai, its sister-species. By one year after infection, the relative length of the hindbody is shorter, and is equal to that of the primitive state found in G. shastai. The phylogenetic relationships among the anuran hosts are re-analyzed. There is 80% congruence between them and the postulated phylogenetic tree for their parasites, suggesting strong historical association between the parasite and host groups. This inference of coevolution is further supported by the concordance of the present geographical distributions of the parasites and their hosts with the historical geology of the areas in which they occur. This implies an historical association between the areas and the organisms. / Science, Faculty of / Zoology, Department of / Graduate

The taxonomy of gnathiids is solely based on the morphology of the adult males since they are more frequently encountered than the other life stages, therefore female and larval gnathiid descriptions are sometimes absent from species descriptions. Thirty-eight of the almost 180 known gnathiid species are described from Australian waters, with 12 of these collected from the Great Barrier Reef. The only described species parasitising elasmobranchs is Gnathia pantherina Smit and Basson, 2002, a species found on South African sharks and rays. Scientists have examined the relationships between host size and abundance of parasitic larval gnathiid isopods on Heron Island. This is an indication that gnathiids do feed on elasmobranchs but the lack of sampling plays a big role. The objectives of this study are therefore to identify three gnathiid species found on various elasmobranchs from Australia. A phylogenetic analysis will be conducted to confirm whether these species belong to the genus Gnathia Leach, 1814, to determine the relationship between Australian and South African gnathiids species and to see whether there is a correlation between phylogeny and geographic distribution of members of this genus. The statistical analysis using Primer version 5 will be used to provide the specific characteristics responsible for these species groupings seen in the cladograms. Gnathiids were collected from 1996 to 1998 and during March 2002 from various elasmobranchs from Australia. The eight shark and ray species collected from Lizard Island, Heron Island (Shark Bay), and Moreton Bay were; Carcharinus amblyrhynchos Bleeker, 1856, Triaenodon obesus Rüppell, 1837, Rhynchobatus djiddensis Forsskål, 1775, Rhinobatos typus Bennett, 1830, Himantura fai Jordan & Seale, 1906, Taeniura lymma Forsskål, 1775, Urogymnus asperrimus Bloch & Schneider, 1801 and Pastinachus sephen Forsskål, 1775. Larval gnathiid isopods were found attached to the gill filaments and septum of all sharks collected, their numbers and attachment positions were also recorded. After removal from hosts, larvae were kept in fresh sea water until they moulted into adult stages. The males did not conform to descriptions of any known gnathiid species, and were considered to be new to science. The descriptions were based on light and scanning electron microscopy observations. Summary 9 A phylogenetic analysis was conducted to determine where these new species fit into the genus Gnathia and where the new genus Tenerognathia Tanaka, 2005 fits into the family Gnathiidae. The species Caecognathia cryptopais Barnard, 1925 was also included in this study to verify whether this species belongs to the genus Caecognathia Dollfus, 1901. Primer version 5 was used to determine the characteristics responsible for the specific groupings identified by the phylogenetic analysis. The results showed that these three species belong to the genus Gnathia and are only found on Australian elasmobranchs. The findings also contributed to new host records for gnathiids. According to the phylogenetic analysis these new species grouped with the only known elasmobranch gnathiid from southern Africa, G. pantherina. These species made a separate grouping within the Gnathia genus indicating that they have specific characteristics that set them apart from other gnathiids. These characteristics were identified using Primer version 5. It appears that elasmobranch gnathiids are to some extent bigger than teleost gnathiids, have a longer pleotelson and their pylopod’s 2nd article is not circular or conical. However, G. pantherina‘s (from southern Africa) 2nd pylopod article is circular as well as gnathiids from teleosts from the rest of South Africa and Australia. This signifies that this characteristic is host and location specific. The genus Tenerognathia grouped within the genus Gnathia. This might be due to incomplete characteristics information that makes up the data-matrix. The species Caecognathia cryptopais grouped within the genus Caecognathia, confirming that its classification was correct. In conclusion these species are newly described gnathiid species found for the first time on Australian elasmobranchs. This brings the number of known gnathiid species found on elasmobranchs to four. All three life stages were described for Gnathia trimaculata sp. n. and Gnathia australis sp. n and only the male and larvae for Gnathia nigrograndilaris sp. n. The phylogenetic analysis confirmed that there is a correlation between Australian and South African elasmobranch gnathiids, elasmobranchs gnathiids and between phylogeny and geographical distribution. / Dr. N.J. Smit

The discovery of the honeybee-specific ectoparasitic mite Varroa destructor in South Africa in October 1997 raised the spectre of massive honeybee colony losses as has occurred in most parts of the world where the varroa mite has been found. This was particularly concerning in Africa because of the importance of honeybees in the pollination of indigenous and commercial crops, and because of the numbers of small-scale beekeepers in Africa. The mite has now spread throughout South Africa and is found in almost all honeybee populations, both commercial and wild, and is also now present in most neighbouring countries. Varroa has not left a trail of destruction in South Africa as had been expected and no large scale collapse of the honeybee population occurred, despite the majority of beekeepers deciding not to protect their hives with chemical varroacides. Some colony losses did occur at the front of the varroa spread, and all colonies were found to be deleteriously affected by the mite which developed populations of 50 000 and more in some colonies. Infected colonies were also not as efficient as pollinators as uninfected colonies. Colonies exhibited all the same varroa effects witnessed in other parts of the world, with the exception that the majority of colonies did not die as a result of the infestation. The relative tolerance of African bees to the varroa mite has been confirmed by the long-term monitoring of both wild honeybee populations and commercial stock, and by population dynamic studies of the mites. In both wild and managed honeybee populations varroa appears to have been reduced to the status of an incidental pest. The development of mite tolerance took 3-5 years in the Cape honeybee (Apis mellifera capensis) and 6-7 years in the Savanna honeybee (Apis mellifera scutellata). The rapid development of mite tolerance in the Cape bee is thought to be due to the well developed removal of varroa-infested brood and the short post-capping period of worker brood. Together these resulted in a very rapid increase in infertile mites in the colony, the collapse of the mite population, and varroa tolerance. Tolerance does not develop as rapidly in Savanna honeybees as the post-capping period in these bees is similar to that of European bees and does not result in as many infertile mites. Nonetheless, varroa tolerance in Savanna bees develops more rapidly than would be the case in European bees because of more effective hygienic removal of varroa-infested brood. In both Cape and Savanna bees, the absence of varroacide applications and a “live-and-let-die” approach to the wild and commercial honeybee populations was crucial to the developed of population-wide varroa tolerance, in contrast to the selective breeding and pesticide treadmill practised in most parts of the world in an effort to get rid of the varroa mite. Varroa destructor is concluded not to be a serious threat to honeybees and beekeeping in Africa, and efforts should be made to prevent the use of pesticides and techniques that could hinder the development of natural mite tolerance in Africa. / Dissertation (MSc (Entomology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

A família Trypanosomatidae compreende parasitas obrigatórios de vertebrados, plantas e invertebrados, as espécies exclusivas de insetos infectam principalmente dípteras e hemípteras. Nós revisamos a taxonomia de Herpetomonas e tripanossomatídeos de insetos que abrigam simbionte (SHT), comparando tripanossomatídeos da América do Sul e África. As filogenias revelaram duas novas espécies e possibilitou revalidar os gêneros Strigomonas e Angomonas. As análises filogenéticas revelaram três novas espécies de endossimbiontes proteobacteriano e apoiam a história evolutiva convergente entre hospedeiros e simbiontes. O DNA barcoding de 364 culturas de moscas identificaram 70 culturas (20%) como Angomonas, 71% deles de Calliphoridae. O gênero Herpetomonas compreende agora 13 espécies válidas, incluindo cinco novas espécies. Algumas espécies de Herpetomonas são parasitas generalistas de moscas e parecem ser tão cosmopolita como seus hospedeiros. Os taxon propostos podem ajudar a elaborar critérios mais eficientes para uma classificação melhor dos tripanossomatídeos. / Trypanosomatidae comprises obligate parasites of vertebrates, plants and invertebrates, the species exclusive of insects infect mostly dipterans and hemipterans. We revise the taxonomy of Herpetomonas and Symbiont Harboring Trypanosomatids (SHTs), by comparing trypanosomatids from South America and Africa. The phylogenies disclosed two new species and revalidated the genera Strigomonas and Angomonas. Phylogenetic analyses revealed 3 new species of proteobacterial endosymbionts and support a co-divergent host-symbiont evolutionary history. DNA barcoding of 364 cultures from flies identified 70 cultures (20%) as Angomonas, 71% of them from Calliphoridae. The recent dispersion of calliphorids was important in the dispersal of Angomonas worldwide. The genus Herpetomonas now comprises 13 valid species including 5 new species. Some species of Herpetomonas are generalist parasites of flies and appear to be as cosmopolitan as their hosts. The proposed taxa may help to elaborate more efficient criteria for a better classification of the Trypanosomatidae.

Internal parasites of cattle are capable of causing great economic loss, but the extent of this loss and the savings that can result from control of cattle parasites have only recently received serious attention. For the past several years extension animal husbandmen and veterinarians have reported with increasing frequency parasitic infections in cattle in the State of Virginia. Hence, the Animal Husbandry Department in conjunction with the Animal Pathology Department of the Virginia Polytechnic Institute initiated in the Autumn and Spring of 1953-1954 a survey in the State to obtain information concerning the incidence of bovine parasitism. Three methods have been utilized in diagnosing specific parasitism in domestic animals. Until recently the method commonly employed has been that of post mortem examination. In this type of examination the various digestive organs are tied off in place and then removed for examination for specific parasites. This method, while affording positive information on the one animal sacrificed, could not be regarded as giving sufficient information on the living animals unless a significant percentage of animals were autopsied. The second method is fecal culture which is usually regarded as too time consuming and involving the services of a technician skilled in identification of infective larvae. Lately, differential egg counts have been employed. This method has the advantage of quick diagnosis of mixed infections without loss of animals to slaughter. Therefore, more animals can be examined and a better estimate of the helminth population as a whole can be obtained. The principal disadvantage of this method lies in errors due to mis-identifications of the ova. The 1953-1954 survey employed the differential egg count method. The present study is an outgrowth of the problem of identifying, with reasonable accuracy, some of the commonly occurring species of nematode ova found in samples of cattle feces. / Master of Science

Portunion conformis castrates the crab Hemigrapsus oregonensis. Piltz (1969) found P. conformis in both H. oregonensis and Hemigrapsus nudus. Kuris (1971) studied the interactions between P. conformis and H. oregonensis occurring in Bodega Bay, California. In the present study, interactions between this isopod and populations of both hosts in Tomales Bay, California, are described, including the influence of host species, sex and size on parasitic infestation and the effects of the parasites on secondary sexual characteristics of the hosts, as well as interactions between the effects of these variable.

Toxocara canis (Werner, 1782) is the most common nematode parasite of dogs. In parts of the United States 21% of all dogs are infected with this intestinal roundworm (Ehrenford, 1957). In Provo, Utah, where 97 adult dogs were examined, 17. 5% harbored T. canis adults (Fox, personal communication).