Trypanoxyuris (Trypanoxyuris) minutus (Schneider, 1866) among Alouatta guariba clamitans (Cabrera, 1940) in the state of Rio de Janeiro, Brazil.

This study reports on infection by Trypanoxyuris (Trypanoxyuris) minutus among Alouatta guariba clamitans through biometry on adults and eggs. A total of 58 adult helminths were recovered from the small segment of the animal's large intestine. This study is the first report of this parasite among A. guariba clamitans in Rio de Janeiro.

Prevalence, pathology and risk factors for coccidiosis in domestic rabbits (Oryctolagus cuniculus) in selected regions in Kenya.

BACKGROUND: The potential for rabbit production in Kenya is high. However, high morbidity and mortality of domestic rabbits were reported. OBJECTIVE: The aim of the study was to determine the pathology, prevalence and the predisposing factors to coccidiosis in domestic rabbits in selected regions in Kenya. ANIMALS AND METHODS: A total of 61 farms keeping rabbits in six different counties were visited in the survey. A total of 2680 live rabbits were examined and 61 rabbits and 302 fecal samples were randomly collected from the farms and examined for coccidian oocysts by ante-mortem and post-mortem methods. The predisposing factors to coccidiosis were assessed through questionnaires and direct observation. Chi square (χ(2)) statistics was used with P values < 0.05 considered statistically significant. RESULTS: Of the 302 fecal samples, 85% (P < 0.001) contained coccidian oocysts and 2% harbored nematode eggs (Passalurus ambiguous). The overall prevalence of Eimeria spp. infestation was 85.1% in the study area and 90.2% in the individual rabbits, while prevalence of intestinal coccidiosis and hepatic coccidiosis was 29.5% and 11.5%, respectively. Higher counts of coccidian oocysts per gram of feces were recovered in weaners than in growers and adults rabbits (P < 0.001), rabbits that were kept in high density group housing (P < 0.05) and housing with more than two tiers. CONCLUSION: This study identified group housing of rabbits of different ages and inadequate control of concurrent infections as the major risk factors associated with coccidiosis in domestic rabbits in Kenya.

Redescription of Ichthyouris bursata Moravec & Prouza, 1995 (Nematoda: Pharyngodonidae), a parasite of wild and aquarium-reared discus Symphysodon spp. (Osteichthyes).

The oxyuroid nematode Ichthyouris bursata Moravec & Prouza, 1995 (Pharyngodonidae) was recorded from the intestine of discus (Symphysodon spp. and hybrids) cultured in discus farms in Bangkok and Nonthaburi, central Thailand, during 2006 and 2007. This material made it possible to study in detail the morphology of this little known parasite species, using both light and scanning electron microscopy (the latter not previously used for the male). The SEM examination showed taxonomically important morphological features not previously reported or erroneously described, including the presence of three bilobed lips, a pair of sclerotised plate-like structures and a median cone-shaped outgrowth on the posterior cloacal lip, short 'hairs' on the cloacal lips, digital phasmids in the male and, sometimes, up to two filaments on the egg poles. This species is of South American origin, which was confirmed by its recent record from a free-living blue discus S. aequifasciatus Pellegrin in Brazil. The reproduction and transmission of I. bursata in the conditions of aquarium tanks is probably permitted by the direct (homoxenous) life-cycle of this parasite.

Molecular characterization of Thelastomatoidea (Nematoda: Oxyurida) from cockroaches in Australia.

A molecular approach was used to genetically characterize 5 species (Aoruroides queenslandensis, Blattophila sphaerolaima, Cordonicola gibsoni, Desmicola ornata and Leidynemella fusiformis) belonging to the superfamily Thelastomatoidea (Nematoda: Oxyurida), a group of pinworms that parasitizes terrestrial arthropods. The D3 domain of the large subunit of nuclear ribosomal RNA (LSU) was sequenced for individual specimens, and the analysis of the sequence data allowed the genetic relationships of the 5 species to be studied. The sequence variation in the D3 domain within individual species (0-1.8%) was significantly less than the differences among species (4.3-12.4%). Phylogenetic analyses, using maximum parsimony, maximum likelihood, and neighbour-joining, tree-building methods, established relationships among the 5 species of Thelastomatoidea and Oxyuris equi (a species of the order Oxyurida). The molecular approach employed provides the prospect for developing DNA tools for the specific identification of the Thelastomatoidea, irrespective of developmental stage and sex, as a basis for systematic, ecological and/or population genetic investigations of members within this superfamily.

Evolutionary patterns in life histories of Oxyurida.

The Oxyurida comprises some 850 known species that occur in the intestine of arthropods and vertebrates (one species in annelids). Important arthropod hosts include Diplopoda, Blattodea, Gryllotalpoidea, Passalidae, Scarabaeida and Hydrophilidae. The major vertebrate hosts are lizards, tortoises, primates, rodents and lagomorphs. An underlying characteristic of the group is haplodiploid reproduction and like many haplodiploid groups, pinworms tend to have life histories that involve high levels of inbreeding. Unlike Strongylida, Ascaridida and Spirurida, which have diversified in tissue site and life cycle as well as hosts, pinworms show little variation in these features and have radiated only across host groups. Two explanations are advanced for this. Haplodiploidy and its concomitant inbreeding may act to canalise evolutionary change, although diverse groups such as the Hymenoptera belie this. Alternatively, Strongylida, Ascaridida and Spirurida are presumed to have arisen from skin-penetrating ancestors that were forced to undergo a tissue migration before reaching their primitive tissue site, the gut. This migration demanded they adapt to a variety of tissue sites and thus acted as a preadaptation to further diversification. The Oxyurida, in contrast, probably arose using oral contaminative transmission. The lack of exposure to other tissue sites may therefore have relegated pinworms to their position in the posterior gut.