Prevalence and biodiversity of helminth parasites in donkeys from South Africa

Seven donkeys (Equus asinus) from North-West and Mpumalanga Provinces in South Africa were examined at necropsy. Quantitative samples were collected from the gastrointestinal tract for recovery of helminth parasites from the stomach, small intestine, cecum, ventral colon, dorsal colon, descending colon, and cranial mesenteric artery. Fifteen genera and 29 species of helminths were identified comprising 27 species of nematodes in the Ascarididae, Atractidae, Habronematidae, Onchocercidae, Oxyuridae, and Strongylidae; 1 species of cestode in the Anoplocephalidae; and 1 species of trematode in the Paramphistomatidae. In addition, 2 species of oestrid fly larvae in the Gastrophiliidae were identified. The most abundant group in number of species was the cyathostomes (small strongyles) and, of these, Cyathostomum montgomeryi, Cylicocyclus sp. (a), and Cylicostephanus minutus were the most numerous. The most prevalent cyathostomes were C. montgomeryi and Cylicocyclus sp. n. (a). Strongylus vulgaris was the most abundant and prevalent large strongyle species. The occurrence of small strongyle species and their prevalences in this study are compared with 3 other studies on donkeys in Africa.     

Nematode parasites from Burchell's zebras in South Africa

Twenty-five Burchell's zebras (Equus burchelli antiquorum) which were culled at monthly intervals in the Kruger National Park were examined for helminths. Twenty-nine species of nematodes belonging to the families Atractidae, Habronematidae, Onchocercidae, Oxyuridae, Strongylidae, Strongyloididae and Trichostrongylidae were recovered. The cyathostomes (small strongyles) most abundant were Cyathostomum tetracanthum, Cylicostephanus calicatus, Cylindropharynx sp. (? C. intermedia Theiler, 1923) and Cylicocyclus auriculatus. Cyathostomum alveatum, Cyathostomum montgomeryi, Cylicostephanus calicatus and Cylindropharynx sp. (? C. intermedia Theiler, 1923) were the most prevalent cyathostomes (small strongyles) while Craterostomum acuticaudatum was the most prevalent of the large strongyles. Of all the species recovered those most abundant were Crossocephalus viviparus and Probstmayria vivipara with intensities of 100 to 3,857,772 and 18,400 to 104,120,467, respectively. Four new species, two Triodontophorus spp. (Strongylidae) and two Habronema spp. (Habronematidae) were identified. Furthermore, this study furnishes a first report of Triodontophorus minor in zebras. The fourth stage cyathostomes as well as the adults of 11 of the 14 species were present in significantly greater intensities in autumn and winter.     

Gastro-intestinal helminth parasites of the chacma baboon, Papio cynocephalus ursinus, from the coastal lowlands of Zululand, South Africa

An examination of 191 faecal samples from Papio cynocephalus ursinus from Mkuzi Game Reserve, Natal, South Africa, has revealed low prevalence rates for a high diversity of gastro-intestinal helminths. This high diversity, including the first evidence for an acanthocephalan infection in South African baboons, is compared to that from montane baboons studied previously.     

Distribution and habitats of Bulinus natalensis and its role as intermediate host of economically important helminth parasites in South Africa

This article focusses on the geographical distribution and habitats of Bulinus natalensis, as reflected by the samples taken from 244 collection sites on record in the database of the National Freshwater Snail Collection (NFSC) at the Potchefstroom campus of the North-West University. This snail species is experimentally susceptible to Schistosoma haematobium and is incriminated in the natural transmission of S. margrebowiei, S. bovis and Calicophoron microbothrium elsewhere in Africa. The 78 different loci (1/16 degree squares) on record reflect a geographical distribution that is largely limited to the KwaZulu-Natal Province. Details of each habitat as described by collectors during surveys, as well as altitude and mean annual air temperature and rainfall for each locality, were processed and chi-squared and effect size values calculated. A decision tree constructed from all the available data indicated that temperature and altitude, followed by the type of water body, seemed to be the more important factors that significantly influenced the distribution of this species in South Africa. The possible role of this species as intermediate host of economically important helminth species is briefly examined. The need to clarify its relationships with B. tropicus and B. depressus, and to update the geographical distribution in South Africa, is also emphasised.     

Studies on the helminth parasites of voles and shrews from Wales

The incidence and degree of infestation of the Bank vole, Clethrionomys glareolus , the Skomer vole, C. skomerensis , the Common shrew, Sorex araneus and the Pygmy shrew, S. minutus have been studied from a rough grassland and woodland area, Aberystwyth and from Skomer Island in Wales. In addition, small numbers of the Short-tailed vole, Microtus agrestis and the Water shrew, Neomys fodiens were examined for helminth parasites, when they became available. Seven new host records and six new British records are listed. The number of species of helminths in shrews, which consisted largely of digeneans and cestodes, was greater than that in voles. This is undoubtedly linked with differences in the feeding habits of the two hosts.
In Aberystwyth, where the composition of the helminth fauna was found to be more varied than that from Skomer Island, one species of nematode showed evidence of seasonal variation in the degree of infestation of Clethrionomys glareolus and four species, one digenean, two cestodes and one acantocephalan in Sorex araneus. The factors affecting this seasonal fluctuation in parasite numbers are discussed.     

The gastrointestinal parasites ofPapio ursinus from the Drakensberg Mountains,Republic of South Africa

One hundred twenty-two fecal samples were collected from two troops of chacma baboons (Papio ursinus),living in montane and subalpine grassland, trespectively. These were examined for the presence of gastrointestinal parasites. Five protozoan, six nematode, and two cestode species were identified. Identifications were based on the morphology of cysts in the case of Protozoaand of eggs in the case of helminths. Strongyle nematodes were tentatively identified on egg size ranges and larval characteristics.     

Characterization of the carcinoma-associated Tk antigen in helminth parasites

Expression of Tk antigen, a truncated carbohydrate antigen, was examined in helmith parasites. Using the monoclonal antibody LM389, this antigen was detected in extracts from Taenia hydatigena, Mesocestoides vogae (syn corti), and Taenia crassiceps. No reactivity was observed in Thysanosoma spp., Dipylidium caninum, Fasciola hepatica, and Nyppostrongylus brasiliensis. On the basis of their electrophoretic mobility, different patterns of Tk-bearing glycoproteins were observed among T. hydatigena, M. corti and T. crassiceps by immunoblotting, with certain components resolved as broad bands typical of mucin-like glycoproteins. Most Tk-reactive material remained in the 0.6 N perchloric acid-soluble fraction, confirming that Tk epitopes are carried by mucin-type glycoproteins. Immunohistochemical analysis revealed that in T. hydatigena, Tk antigen is mainly expressed in the tegument, whereas in M. corti the reactivity was principally observed in the subtegumental parenchyma. The presence of a novel tumor-associated carbohydrate antigen in invertebrates, contributes to strengthen the notion that truncated mucin-type O-glycosylation is a normal phenomenon in parasitic worms and may help identify new biological characteristics of helminth parasites.     

Cylicocyclus asini n. sp. (Nematoda: Cyathostominae) from donkeys Equus asinus in South Africa

Cylicocyclus asini n. sp. is described from the ventral colons of seven domesticated donkeys Equus asinus in South Africa. The specimens are smaller than 11 members of the genus Cylicocyclus, which currently comprises 10 recognised species, one recognised subspecies and two species inquirendae, but is similar in size to the two smaller species, C. ashworthi and C. leptostomum. Additionally, the small size of its buccal capsule places it within the so-called small buccal capsule group, namely C. ashworthi, C. leptostomum, C. nassatus, C. radiatus and C. triramosus. The shape of the oesophagus at the oesophago-intestinal junction is elongate, similar to that of C. leptostomum. The female specimens have a tail length shorter than the vulva to anus distance, similar to three of the smaller Cylicocyclus species, namely C. leptostomum, C. radiatus and C. triramosus. The new species is distinguished from the smaller members of the genus by the presence of a `club-foot' posterior in the female specimens, 40–46 elements in the external leaf-crown and a deep division of the dorsal ray which extends beyond the origin of the externodorsal ray. Similarly, the new species can be separated from the two other members in the genus with a `club-foot' posterior in the females (C. auriculatus and C. gyalocephaloides) by its body length (6.6–8.47 mm) and the presence of a nipple-like dorsal gutter.     

Density dependence and the control of helminth parasites

1. The transient dynamics and stability of a population are determined by the interplay between species density, its spatial distribution and the positive and negative density-dependent processes regulating population growth. 2. Using the human-helminth parasite system as an example, we propose that the life-stage upon which negative density dependence operates will influence the rate of host reinfection following anthelmintic chemotherapy, and the likely success of control programmes. 3. Simple deterministic models are developed which highlight how a parasite species whose population size is down-regulated by density-dependent establishment will reinfect a host population at a faster rate than a species with density-dependent parasite fecundity. 4. Different forms of density dependence can produce the same equilibrium behaviour but different transient dynamics. Under-representing the nature and magnitude of density-dependent mechanisms, and in particular those operating upon establishing life-stages, may cause the resilience of the parasite population to a control perturbation to be underestimated.     

Studies on the helminth parasites of freshwater fishes of the Sudan

2419 freshwater fishes from the Sudan were examined for helminth parasites and found to harbour one monogenean species, 15 species of adult digenetic trematodes, three species of larval trematodes, 16 species of adult cestodes, 13 species of adult nematodes, two species of larval nematodes and three species of acanthocephalans. Four species of adults and four species of larval worms are recorded for the first time in the Sudan and 30 new hosts are listed. The intensity of infestation of each species, the host-specificity and the variations in the infestation of fishes are discussed. The helminth fauna of the Sudan is compared with that of other African countries.     

Descriptive epidemiology of intestinal helminth parasites from stray cat populations in Qatar

A total of 488 stray cats, 212 adult and 29 juvenile females plus 235 adult and 12 juvenile males, were examined post-mortem during the winter and summer months of 2006 from five sites in the vicinity of Doha and its outskirts. Five helminths, comprising three nematode and two cestode species were identified and the majority of cats harboured two of these species. The most prevalent was the cestode Taenia taeniaeformis (75.8%), followed by the cestode Diplopylidium sp. (42.8%), and the nematodes Ancylostoma tubaeforme (17.0%), Physaloptera sp. (6.6%) and Toxocara cati (0.8%). All five species were found to be typically overdispersed in their distribution. Using univariate and multivariate analyses, the prevalence and abundance of infections were primarily influenced by host gender and season, with females tending to harbour higher levels of infection during the summer. No significant differences were found relative to site except in the case of Physaloptera sp. Using bivariate Pearson product moment correlations, significant positive co-occurrences were identified between Diplopylidium sp. and T. taeniaeformis and also between A. tubaeforme and T. taeniaeformis. The results are discussed in relation to the effect of environmental conditions on the intestinal helminth infracommunities and their possible interactions in stray cat populations from such a harsh and arid region as Qatar.     

Checklist of the helminth parasites of vertebrates in Costa Rica

Helminth parasites of vertebrates have been studied in Costa Rica for more than 50 years. Survey work on this group of parasites is far from complete. We assembled a database with all the records of helminth parasites of wild and domestic vertebrates in Costa Rica. Information was obtained from different sources such as literature search (all published accounts) and parasite collections. Here we present a checklist with a parasite-host list as well as a host-parasite list. Up to now, 303 species have been recorded, including 81 species of digeneans, 23 monogeneans, 63 cestodes, 12 acanthocephalans, and 124 nematodes. In total, 108 species of vertebrates have been studied for helminths in Costa Rica (31 species of fishes, 7 amphibians, 14 reptiles, 20 birds, and 36 mammals). This represents only 3.8% of the vertebrate fauna of Costa Rica since about 2,855 species of vertebrates occur in the country. Interestingly, 58 species (19.1 %) were recorded as new species from Costa Rica and most of them are endemic to particular regions. Considering the valuable information that parasites provide because it is synergistic with all the information about the natural history of the hosts, helminth parasites of vertebrates in Costa Rica should be considered within any initiatives to accomplish the national inventory of biological resources. Starting with this compilation work, the Colección de Helmintos de Costa Rica (CHCR), hosted at the Facultad de Microbiología, Universidad de Costa Rica, has re-emerged and it is our hope that it will have the standards of quality to assure that it will become the national depository of helminths in the country.     

Epidemiology of intestinal helminth parasites in stray dogs from markets in south-eastern Nigeria

A survey of gastrointestinal helminth parasites of stray dogs (Canis familiaris) was conducted at Obollo-Afor and Ekwulobia markets, in Enugu and Anambra States, south-eastern Nigeria, respectively, to determine the patterns of infection among dogs in different parts of south-eastern Nigeria. Faecal samples collected, using long forceps, from every dog encountered in the markets between June 2007 and December 2008 were analysed by the Kato-Katz technique. Out of 413 dogs examined in both markets, 217 (52.6%) were infected with at least one of five parasites (Toxocara spp., Dipylidium caninum, Ancylostoma caninum, Taenia spp. and Trichuris vulpis). Overall faecal egg intensity of infection was 49.9?±?58.7 eggs/g (epg). The prevalence of infection was comparable between the markets and between the male and female dogs, but varied significantly (P?相似文献   

Comparative histochemical observations on the excretory system of helminth parasites.

The excretory canals of Ascaridia galli (Nematoda) and the protonephridial ducts of Cotylophoron cotylophorum (Trematoda) and Raillietina cesticillus (Cestoda) have been studied with regard to the histochemical localization of lipids, carbohydrates and hydrolytic enzymes. Distinct excretory organs are absent in the acanthocephalan Centrorhynchus corvi. Triglycerides, phospholipids and lipoproteins are seen in association with the wall of excretory canals of A. galli and R. cesticillus, and phospholipids and lipoproteins at the corresponding site in C. cotylophorum. The physiological significance of lipids in association with excretion of substances has been discussed. Low molecular weight glycogen is present in the lumen of excretory canal of A. galli but not in other worms. The common feature of the excretory canals is the presence of enzyme activities of nonspecific alkaline phosphatase and Mg2+-dependent ATPase. Activity of acid phosphatase is seen only in the excretory canals of A. galli. Glucose-6-phosphatase is present in A. galli and C. cotylophorum and absent in R. cesticillus. Weak reaction of 5'-nucleotidase is present in the excretory canals of helminth species studied here. The role of these enzymes in transportation of substances across the wall of excretory canals and also in ionic regulation has been discussed in detail.     

Studies on the helminth parasites of the Long-tailed field mouse, Apodemus sylvaticus sylvaticus from Wales

The incidence and degree of infestation of the Long-tailed field mouse, Apodemus sylvaticus with helminth parasites have been studied from a rough grassland and woodland area, Aberystwyth and from Skomer Island in Wales. With few exceptions, adult mice were more heavily infested than juveniles.
In Aberystwyth, where the composition of the helminth fauna was found to be more varied than that from the island of Skomer, three species of helminths, one digenean and two nematodes, showed evidence of seasonal variation in the degree of infestation of mice. The factors affecting this fluctuation in parasite numbers throughout the year are discussed.
It is suggested the distribution of helminths in the mouse population may be represented by a negative binomial, indicating that the infective eggs, larvae or intermediate hosts of the respective helminths were aggregated in their distribution in the selected areas of study.