Genetic and morphological heterogeneity in small rodent whipworms in southwestern Europe: characterization of Trichuris muris and description of Trichuris arvicolae n. sp. (Nematoda: Trichuridae)

Genetic and morphological variability of whipworms Trichuris Roederer, 1761 (Nematoda: Trichuridae), parasites of small rodents in southwestern Europe, was studied. Isozyme patterns of natural populations of nematodes parasitizing rodent species of the Muridae (Apodemus sylvaticus, Apodemus flavicollis, Mus musculus) and Arvicolidae (Clethrionomys glareolus, Microtus agrestis, Microtus arvalis) were analyzed at 6 putative loci. Two diagnostic loci were found in T. muris from Muridae and from Arvicolidae. Thus, the existence of 2 species of Trichuris restricted to different host families was indicated. They included Trichuris muris Schrank, 1788, originally described as being from mice, and Trichuris arvicolae n. sp., parasitizing the above species of Arvicolidae. The morphological variability of both species was compared. Although ranges of all morphological characters of the new species overlapped with those of T. muris, stepwise discriminant analysis yielded a 100% accurate classification of females when using vagina length and egg size. Males of T. muris and T. arvicolae cannot be separated entirely. A set of 6 variables yielded 95.7% discrimination; the most discriminating variables were spicule size and body width.     

New species of Trichuris (Nematoda:Trichuridae) from Akodon montensis, Thomas, 1913, of the Paranaense Forest in Argentina

Species of Trichuris (Nematoda:Trichuridae) parasitize a broad range of mammalian hosts. To date, 21 Trichuris species infecting nine families of rodents have been found in North and South America. Trichuris navonae n. sp. is described on the basis of specimens recovered from a species of forest-dwelling mice, Akodon montensis (Cricetidae: Sigmodontinae), from nine localities of Misiones Province, Argentina. A comparison with all the species of Trichuris from North and South American rodents is given. The separation of the new species of Trichuris is based on morphologic and morphometrica features, such as the absence of a spicular tube, the presence of a cylindrical spicular sheath with sharp spines, a non-protrusive vulva, a long anterior-posterior portion of the body, a lengthy spicule, and a proximal and distal cloacal tube. This is the third record of this genus in rodents of the Sigmodontinae from Argentina and the fifth record from South American rodents. Despite the large number of potential host species, only about 1.9% of sigmodontine rodent species have been reported as hosts of Trichuris spp. It is suggested that this number represents but a small fraction of Trichuris spp. that occur in sigmodontine rodents, and that additional survey of this group should yield additional species.     

Lipid metabolism in Trichuris globulosa (Nematoda)

Adult males and females of Trichuris globulosa, an intestinal nematode parasite of goats, were studied for their lipid composition, capability of incorporation of (Na)-1-14C-acetate into different lipid classes and the activity of certain key enzymes of lipid metabolism. The parasite possesses a large variety of lipids including certain complex lipids. These are phosphatidylcholine (PC), diphosphatidylglycerol (cardiolipin), lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), phosphatidylserine (PS), phosphatidylinositol (PI), plasmalogens (choline + ethanolamine), mono-, di- and triacylglycerols, free and esterified cholesterol, non-esterified fatty acids (NEFA), gangliosides, cerebrosides (glycosyl ceramide) and sulphuric acid esters of cerebrosides (sulphatides). The females contain more lipids than males, particularly the acylglycerols and phospholipids, possibly to meet the energy requirement and structural entities for the daily production of large numbers of eggs. Incorporation studies of labelled substrate, sodium-1-14C acetate demonstrate that the adult female has extremely active mechanisms for biosynthesizing these lipids. Most of the labels are found in PC, PE, SM, acylglycerols, NEFA, gangliosides, cerebrosides and sulphatides. Cholesterol, although a minor component of the parasitic lipids, incorporates large amount of label and also undergoes fast turnover. Kinetic analysis of the incorporation by measuring the rate constant (k) and half life (t1/2) reveals that gangliosides are the fastest biosynthesizing and turning over lipids, although they constitute only 0.1% of the total lipids. The presence of important enzymes of lipid biosynthesis, glucose-6-phosphate dehydrogenase, malate dehydrogenase and hydroxymethyl glutaryl-CoA reductase and an enzyme of lipid ester hydrolysis, triacylglycerol lipase, is also established in T. globulosa. Michaelis-Menten kinetic characteristics of the parasitic enzymes (Km, Vmax, v and the first order rate constant, k) are comparable with those of rat liver homogenates.     

Characterization of glucose uptake by Trichuris globulosa (Nematoda) in vitro

14C-glucose uptake by adult Trichuris globulosa is found to be a non-linear function of time and limiting substrate concentration. The uptake is a two component process, an initial rapid burst is followed by a lower steady state, implying a mediated process. The uptake is dependent on Na+ ions which cannot be replaced by K+, Li+ or choline. The uptake is also dependent on pH, being maximal at pH 7.4. 14C-glucose absorption is markedly inhibited by glucose, phlorizin, ouabain and to a smaller extent by a number of monosaccharides and other sugar-phosphates, nucleosides and metabolic inhibitors like p-nitrophenyl phosphate and iodoacetate. The inhibition constant for glucose, phlorizin and ouabain has been found to be 8 mM, 5 mM and 7 mM, respectively. A modified Dixon-plot shows that glucose is a completely competitive inhibitor for 14C-glucose uptake while the nature of competitive inhibition of phlorizin and ouabain are found to be partial.     

Description of a new Capillariinae (Nematoda: Trichuridae) from Scapteromys aquaticus (Cricetidae: Sigmodontinae) from Buenos Aires, Argentina

A new species of Capillaria is described on the basis of specimens recovered from the intestine of the swamp rat Scapteromys aquaticus (Cricetidae: Sigmodontinae) from Argentina. Capillaria alainchabaudi n. sp. and a peculiar species from Australian marsupials are the only 2 species of Capillaria sensu stricto parasitic in mammals. A comparison with the Australian species and with the 18 species of this genus described from other vertebrates from the Western Hemisphere is given. The separation of the new species is based on morphologic and morphometrical features, such as intestine ending in cloaca beside ejaculatory duct, 2 lateral nonmembranous caudal lobes, 2 pairs of caudal non-pedunculated papillae, terminal part of cylindrical cirrus ornamented with thin and thick spines, spicule with apex not well sclerotized in the males, a conspicuous vulvar appendage in the females, and 2 bacillary bands. A survey of the literature revealed that the species of Capillariinae from rodents belong to 9 genera, and the total number of species is low compared to the high diversity and abundance of the hosts, particularly if the modern Muroidea are considered.     

Concurrent infection of a Patas monkey (Erythrocebus patas) by Citrobacter freundii and Trichuris trichiura

Concurrent infection of Citrobacter freundii and Trichuris trichiura in a Patas monkey (Erythrocebus patas) is reported. A synergistic effect of both organisms contributing to host mortality in this case is suggested.     

Trichuris trichiura Infection Diagnosed by Colonoscopy: Case Reports and Review of Literature

Trichuris trichiura, commonly referred to as a whipworm, has a worldwide distribution, particularly among countries with warm, humid climates. In Korea, trichuriasis was a highly prevalent soil-transmitted helminthiasis until the 1970s. However, the nationwide prevalence decreased to 0.02% in 2004 as a result of national control activities and improvement in the socioeconomic status of Koreans. Most infected individuals have no distinct symptoms, if lightly infected. The diagnosis is typically confirmed by detection of T. trichiura eggs on examination of a stool sample; few reports have described detection of the parasite during colonoscopy. Recently, we managed 4 patients with trichuriasis who were diagnosed by detection of the parasite on colonoscopy, and we reviewed the literature on the colonoscopic diagnosis of T. trichiura in Korea. We suggest that colonoscopy might be a useful diagnostic tool, especially when infected by only a few male worms with no eggs in the stool.     

Trichuris odocoileus sp. n. (Nematoda: Trichuridae) from white-tailed deer, Odocoileus virginianus, in southeastern U.S., and a key to trichurids in North American ruminants

A new species of Trichuris from the cecum of white-tailed deer, Odocoileus virginianus, from the southeastern United States, is characterized herein. Males had spicules 2.20 to 3.05 mm long with bluntly rounded tips, an ejaculatory duct equal to or slightly longer than the vas deferens, and a spinous spicular sheath with an expansion near its center. Females had a spinous vulva, usually not everted, a loop in the oviduct just before it opened into the uterus, and a slightly curved posterior portion. Trichuris odocoileus was differentiated from T. lani , a species described in Russia which is most like T. odocoileus, by 1) possessing a spicular sheath with a central expansion, 2) greater size with longer ejaculatory duct and vas deferens, 3) slightly larger eggs, and 4) the unique loop in the oviduct. Trichuris odocoileus constitutes the 6th species of Trichuris recovered from North American ruminants. A key is provided to facilitate differentiation of the six species.     

Capillaria procyonis sp. n. (Nematoda: Trichuridae) from the esophagus of the raccoon, Procyon lotor.

A new species of nematode, Capillaria procyonis, is described from the esophageal epithelium of the raccoon in southern Louisiana. This species is distinguished from other similar mammalian capillarids found in this location by the terminal location of the anus and more posterior postion of the vulva in the female. In the male there is a much longer cirrus and spicule and a unique bursalike expansion of the posterior extremity. The systematics and biological implications of the new species are discussed in relation to similar forms from carnivorous and insectivorous mammals.