Helminths of the horned leaf frog, Proceratophrys appendiculata, from southeastern Brazil

The helminth fauna of the horned leaf frog, Proceratophrys appendiculata (Anura: Leptodactylidae), was studied from 17 adult individuals from an island in Rio de Janeiro state, southeastern Brazil. A total of five nematode species (Aplectana delirae, Cosmocerca brasiliense, Schulzia travassosi, Rhabdias androgyna and Physaloptera sp.) and an unidentified cestode were recovered from the digestive tract, lungs and gall bladder of P. appendiculata and all the nematode species are new host records. Aplectana delirae had the highest values for the prevalence and intensity of infection and can thus be considered a core species in the helminth community of P. appendiculata. Aplectana crossodactyli Baker, 1980 is synonymized with Aplectana delirae (Fabio, 1971). The helminth fauna of P. appendiculata presents characteristics typical of those in amphibians.     

Infestation of the blue mussel Mytilus galloprovincialis by the copepod Pseudomyicola spinosus and its relation to size,density, and condition index of the host

The copepod Pseudomyicola spinosus infests marine mussels and other commercial bivalve species. There is a lack of information on the infestation process and on its relationship to size, density, and health of the host. To obtain this information, an infestation study of the copepod in Mytilus galloprovincialis in field conditions was carried out. Results showed that the intensity of infestation is closely related to host size [F((2,810))=198.33; p<0.001], but not to density [F((2,810))=0.96; p<0.38]. After an initial colonization of the host by the infested copepodite stages, an equilibrium between the intensity of the infestation and host size is maintained; mean intensity in small mussels was 1.57, in medium mussels it was 4.23, and in large mussels it was 9.86. Adult stages were observed after a period of 30 days, and ovigerous females were observed after a period of 45 days. Copepods may be found on the branches and mantle (89.5%) and inside the digestive tract (10.5%); in this last case and at the end of the study period some histological disorders were found such as obstruction of the intestine, rupture of the digestive epithelia, and encapsulations around digestive tissues. Most infested mussels showed the lowest meat weight in relation to shell weight; however, the reproductive stage may affect this observation.     

Seasonal variation in gut morphology in wild rabbits (Oryctolagus cuniculus)

It is shown experimentally that diet composition affected the sizes of several digestive organs in juvenile rabbits collected from the wild. Stomach weight, small intestine volume and colon length were larger in rabbits reared on diets higher in fibre. Small intestine weight, however, was lower.
Analysis of natural variation in wild adult rabbits showed that all digestive organs (except for the appendix) were larger in rabbits living on chalk soils than in those living on sand or clay. Seasonal variation was more marked in males than in females, probably because of the sexes' different breeding requirements. Thus most male digestive organs were smaller between December and June than at other times of year. Female digestive organs did not show this pattern, and were largest in May/June, when the demands of pregnancy and lactation are highest. However, food quality may have been important too. Food quality is probably highest in April, and most digestive organs were then smallest (both sexes). The dry weights of stomach and small intestine did not fit these patterns. Stomach weight increased with the presence of the nematode parasite Graphidium strigosum and small intestine and caecal volumes with the presence of cestodes. Numbers of nematodes (Trichostrongylus retortaeformis and Passalurus ambiguus) in the caecum or colon, however, had no effects on organ sizes.
Data are presented on variation in intensity and prevalence of these helminth parasites with season and soil type.     

Anatomy and histology of the gastrointestinal tract of the neo-tropical opossum (Didelphis marsupialis insularis,Allen 1902)

The morphology of the gastrointestinal tract (GI) is a strong indicator of the dietary habits of a species. The goal of this study was to describe the gross and microanatomy of the digestive tract of the neo-tropical opossum (Didelphis marsupialis insularis) and relate them to the animals’ food habits. GI tracts from 12 adult animals were used for this study. Results found the small intestine made up 65.9% of the GI tract, and the stomach was simple with a prominent caecum. Histologically, the oesophageal mucosa was non-keratinized and glands were found throughout the oesophagus. The large intestine showed a great number of goblet cells, the jejunum possessed well-developed villi, and Peyer's patches were absent in the ileum. The absence of keratinization of the epithelial lining of the oesophagus and stomach and a high lymphocytic infiltration throughout the small and large intestine reflected a more carnivorous diet, whereas the presence of a well-developed caecum in the large intestine indicated the ability to digest plant matter. Overall, the morphology of GI tract of D. m. insularis displayed both carnivorous and herbivorous features, allowing us to conclude that it is an omnivorous animal.     

Does diet variation determine the digestive tract length of Capoeta banarescui Turan,Kottelat, Ekmekci and Imamoglu, 2006?

This study tested the spatial variations in the digestive/intestine tract length of Capoeta banarescui, with regard to their diets in different habitats. Highly varied diets observed in a previous study within the same river system posed the question whether this flexibility is reflected in the digestive tract and intestine length of the species in the Ye?il?rmak River, Turkey. Totals of 382 specimens (standard length 4.6–19.1 cm) were captured by electro‐fishing along the river in September 2012 at 11 locations spanning elevations from 34 to 992 m. The stomach, intestine and total digestive tract lengths were measured, and stomach contents analysed from 196 specimens. For statistical analyses, the stomach, intestine and total digestive tract length were expressed as percentages of total weight and standard length. The data provided evidence that the digestive tract and intestine lengths varied significantly among locations in association with the diet. Fish having dominantly carnivorous diets (e.g. chironomid larvae/invertebrates) in two locations had significantly shorter intestines and digestive tracts than those with diets dominated by benthic algae and other plants. The data indicated that C. banarescui showed broad flexibility in their feeding habits. Feeding heavily on plant materials might lead to the development of longer digestive tracts, increasing the active surface area for digestion; alternatively, there may be less invested in development of the digestive tract when feeding primarily on carnivorous diets where the respective digestive enzymes are readily available. The data suggest that phenotypic plasticity in the digestive tract length of C. banarescui is associated more with the abundant protein‐rich carnivorous food sources in the studied habitats. Whether this digestive tract plasticity has a genetic background remains to be verified in future studies.     

Gastrointestinal helminths of Cuvier's beaked whales, Ziphius cavirostris, from the western Mediterranean

We examined the gastrointestinal helminth fauna of 2 Cuvier's beaked whales, Ziphius cavirostris, stranded on the Spanish Mediterranean coast. Information regarding intestinal parasites of this species is provided for the first time. Six helminth taxa were identified. Thirty type II larvae of the nematode Anisakis sp. were found in the stomach and the intestine of both hosts; 2 type I larvae of Anisakis sp. were found in the intestine of 1 host. One juvenile of the acanthocephalan Bolbosoma vasculosum was found in the intestine; the metacestode Scolex pleuronectis was found mainly in the terminal colon and the anal crypts of both hosts; adult cestodes of Tetrabothrius sp., which may represent a new species, were collected from the duodenum of 1 host. Composition of the intestinal parasitic community is similar to that of other oceanic cetaceans, which mostly include species of Bolbosoma and tetrabothriids (Cestoda).     

A survey of the gastrointestinal nematodes of Spanish ibex (Capra pyrenaica) in a high mountain habitat

We analyzed the content of the abomasum (n = 79) and small intestine (n = 83) of Spanish ibex from Sierra Nevada Natural Park, southern Spain. Fifteen species of trichostrongylid nematodes were identified, 4 of which were found for the first time in this host, i.e., Nematodirus fillicollis, N. oiratianus, Ostertagia lyrata, and O. ostertagi. Teladorsagia circumcincta and Marshallagia marshalli were the most abundant abomasal species, whereas N. abnormalis, N. davtiani, and N. oiratianus were dominant in the small intestine. Counts of both abomasal and intestinal nematodes were generally low (year-round-median = 292 and 94 worms, respectively), and significantly lower numbers of M. marshalli, N. davtiani, and N. oiratianus were found in summer. No sex-related differences in helminth abundance were found, but young ibex harbored significantly more N. davtiani and N. oiratianus than adults. The presence of scabies was not related to increased nematode counts.     

Explaining co-occurrence among helminth species of lesser snow geese (Chen caerulescens) during their winter and spring migration

The digestive tracts of 771 lesser snow geese (Chen caerulescens) collected from January to May 1983 from 12 locations (27 samples) were examined for helminth parasites to determine whether parasite species present in wintering geese or in spring migrants occurred independently of each other. Nine helminth species were identified. Seven had mean prevalences >5% and were the focus of this study. Six of those species were waterfowl generalists, one was a goose specialist. Our primary objective was to assess the potential contribution of factors, other than species interactions, in determining patterns of co-occurrence between helminth species. There were few negative relationships between helminth species, regardless of whether presence-absence or abundance data were used. However, some species pairs showed recurrent and significant co-occurrences. There were similar and significant effects of timing of sampling, host gender, and host age, on prevalence and mean abundance of particular species. Co-occurrences were found for those species that showed seasonal declines in prevalence, for those expected to have high colonizing ability based on host age profiles (using abundance data), and for abundant species that may have shared vectors or environmental conditions favorable for transmission. Thus, similarities between parasites in their abundance, transmission biology, and phenology seem sufficient to explain species co-occurrences without invoking other processes such as species interactions. Received: 18 March 1996 / Accepted: 20 April 1999     

Endohelminth fauna of the marsh frog Rana ridibunda from Lake Hazar, Turkey

In this study, 236 marsh frogs Rana ridibunda collected from Lake Hazar (Elazig, Turkey) at 15 d intervals between March 2001 and February 2002 were examined for endohelminths; of these, 148 (62.71%) frogs were found to be infected with helminths. In total, 9 helminth species (3 trematodes, 5 nematodes and 1 acanthocephalan) were identified. We observed Gorgoderina vitelliloba (prevalence 2.97%) in the urinary bladder, Haematoloechus variegatus (4.66%) and Rhabdias bufonis (8.90%) in the lung, Pleurogenoides medians (1.69%), Oswaldocruzia filiformis (3.81 %) and Acanthocephalus ranae (26.27 %) in the small intestine, Neoxysomatium brevicaudatum (16.95%) and Cosmocercoides sp. (3.39%) in the large intestine, and Eustrongylides excisus (14.41%) in the body cavity and on,the stomach. No helminth was found in the spleen, kidney, gall bladder, liver, heart or muscle. Of the 9 helminth species identified, Acanthocephalus ranae (26.27 %) had the highest prevalence and abundance and Oswaldocruzia filiformis (8.33+/-4.09) had the highest mean intensity.     

Ectoparasites and gastrointestinal helminths of southern flying squirrels in southeast Georgia

Southern flying squirrels (Glaucomys volans) from southeastern Georgia were examined for ectoparasites and gastrointestinal helminths. Ten species of ectoparasites were recovered, including 3 species of sucking lice (Hoplopleura trispinosa, Microphthirus uncinatus, and Neohaematopinus sciuropteri), 1 species of flea (Orchopeas howardi), 2 species of ticks (Amblyomma maculatum and Ixodes scapularis), 3 species of mesostigmatid mites (Androlaelaps casalis, A. fahrenholzi, and Haemogamasus ambulans), and 1 species of chigger (Leptotrombidium peromysci). Only the sucking lice and fleas were common on this host. M. uncinatus is reported for the first time from eastern North America. The 2 most commonly collected ectoparasites, N. sciuropteri (prevalence = 63%) and O. howardi (prevalence = 47%), have previously been shown to be vectors of the rickettsial zoonotic agent that causes sporadic epidemic typhus. Also, 3 nematodes (Citellinema bifurcatum, Strongyloides robusius, and Syphacia thompsoni), 1 unidentified cestode, and 1 acanthocephalan (Moniliformis clarki) were found in flying squirrel gastrointestinal tracts. With the exception of S. thompsoni, which was common and relatively abundant in the cecum (prevalence = 94%, intensity = 51+/-12), both the prevalence and intensity of helminth parasites were low. The nematode S. thompsoni and the acanthocephalan M. clarki are new state records for tree squirrels in Georgia.     

黑斑侧褶蛙消化道重量及长度的性别和季节差异

消化道是联系脊椎动物能量摄入和能量支出之间关系的纽带,其重量和长度对外界环境具有高度的敏感性和弹性(flexibility)。以黑斑侧褶蛙(Pelophylax nigromaculata)为研究对象,测定了山东聊城地区2012年夏季(16只,8♀/8♂)、秋季(19只,9♀/10♂)及翌年春季(17只,8♀/9♂)其体重、体长、胴体湿重和干重系数、总消化道及各段(食道、胃、小肠和大肠)的湿重、干重和长度系数的性别和季节差异(双因素方差分析),对有性别差异的指标,用单因素方差分析分别比较了雌、雄蛙的季节差异。结果显示,1)雌蛙的体重、体长均高于雄蛙,都在秋季最高,春季或夏季最低;雄蛙的胴体湿重系数高于雌蛙,夏季高于秋季;胴体干重系数既无性别差异,也无季节差异。2)除食道湿重系数无性别差异外,雌蛙总消化道及各段的湿重系数均高于雄蛙;除胃湿重系数无季节差异外,春季或秋季的总消化道及各段的湿重系数都高于夏季;雌蛙的总消化道干重和胃干重系数高于雄蛙,食道、小肠和大肠的干重系数无性别差异,所有的干重系数均无季节性差异。3)除雌蛙的大肠长系数高于雄蛙外,总消化道及各段的长度系数均无性别差异,春季和秋季的总消化道长、食道长及胃长系数均高于夏季,小肠长和大肠长系数均无季节性差异。结果表明,随着季节更替,黑斑侧褶蛙消化道各段的重量和长度表现出一定的弹性特征,这与各器官的功能及其生活环境的多样性是相适应的。     

Reproductive traits of the acanthocephalan Neoechinorhynchus brentnickoli in the definitive host

The Acanthocephala constitute a group of helminth parasites that, as adults, infect all classes of vertebrates. Adults of Neoechinorhynchus brentnickoli are parasites of Dormitator latifrons, a commercially important fish species in Tres Palos Lagoon, Guerrero, Mexico. The aim of this study was to describe features of the reproductive biology of this acanthocephalan. Fish were collected from Laguna de Tres Palos during February 2012 to February 2013. The number of fish that were examined (n=688) ranged from 35 (June) to 70 (August) in each collection. The prevalence of infection was more than 90% during this period and mean abundance varied significantly from 32.3 worms per fish (July 2012) to 89.3 worms per fish (March 2012). Acanthocephalans were reproductively active during the whole year. The stomach was the region of the digestive tract with the smallest percentage of helminths, and females were more abundant than males in all sections of the intestine. Larger male and female worms were always located in the more posterior sections of the digestive tract. The mean length at which 50% of individuals reached sexual maturity was 2.9 mm for females and 2.3 mm for males. Relative fecundity increased with length in females.     

Mammalian intestinal allometry,phylogeny, trophic level and climate

An often-stated ecomorphological assumption that has the status of ‘textbook knowledge’ is that the dimensions of the digestive tract correlate with diet, where herbivores—consuming diets of lower digestibility—have longer intestinal tracts than faunivores—consuming diets of higher digestibility. However, statistical approaches have so far failed to demonstrate this link. Here, we collated data on the length of intestinal sections and body mass of 519 mammal species, and test for various relationships with trophic, climatic and other biological characteristics. All models showed a strong phylogenetic signal. Scaling relationships with body mass showed positive allometry at exponents greater than 0.33, except for the caecum, which is particularly large in smaller species. Body mass was more tightly linked to small intestine than to large intestine length. Adding a diet proxy to the relationships increased model fit for all intestinal sections, except for the small intestine when accounting for phylogeny. Thus, the diet has a main effect on the components of the large intestine, with longer measures in herbivores. Additionally, measures of habitat aridity had a positive relationship with large intestine length. The small intestine was longer in species from colder habitats at higher latitudes, possibly facilitating the processing of peak intake rates during the growing season. This study corroborates intuitive expectations on digestive tract anatomy, while the dependence of significant results on large sample sizes and inclusion of specific taxonomic groups indicates that the relationships cannot be considered fixed biological laws.     

黄喉拟水龟消化道的组织学观察

观察黄喉拟水龟消化道的组织结构.采用常规石蜡切片和HE染色方法对黄喉拟水龟的消化道进行观察.除了口咽腔以外,消化道的管壁是由粘膜层、粘膜下层、肌肉层和外膜组成;各部分的主要区别在于粘膜层,食道和大肠的是复层柱状上皮,胃和小肠的是单层柱状上皮.黄喉拟水龟的舌桔红色,不能伸缩;食管中无食管腺,扩张性强;胃呈囊状,有大量胃腺,腔面皱襞较多;小肠较长,是消化的主要场所,表面有大量的绒毛,在绒毛中可见肠腺;大肠无绒毛,也存在皱襞.     

Lesions associated with metazoan parasites of wild platypuses (Ornithorhynchus anatinus)

Pathological findings associated with helminth and arthropod parasites of four wild platypuses (Ornithorhynchus anatinus) are described. Fourth-stage larval rhabditoid nematodes (?Cylindrocorporidae) found partially embedded in the stratum corneum were associated with mild acanthosis, orthokeratotic hyperkeratosis and inconstant subacute dermatits. A filarioid nematode (?Lemdaninae) was found in hypodermal lymphoid tissue. A larval trichostrongyloid nematode was found in the dermis, with no evidence of host response. An undescribed species of trombiculid mite ("chigger") was found in the pelage and attached to superficial stratum corneum. Focal inclusions of eosinophilic material within stratum corneum, interpreted as mite gel saliva produced during formation of the "stylostome," were also observed. The tick Ixodes ornithorhynchi punctured the epidermis causing adnexal trauma, dermal haemorrhage and chronic active dermatitis. The digenean Mehlisia ornithorhynchi was present in the small intestine of one animal and was associated with mild catarrhal enteritis.     

Helminth communities of green frogs Rana clamitans Latreille, from southwestern Michigan.

A total of 239 green frogs Rana clamitans, collected between June 3 and August 27, 1998 from 6 locations in southwestern Michigan, was examined for helminths. Of the 26 helminth taxa found, the larval cestode Mesocestoides sp. had the highest mean intensity, followed by the larval trematode Fibricola sp. Of the helminths that mature in frogs, Haematoloechus varioplexus had the highest prevalence and Gorgodera amplicava had the highest mean intensity. Frogs from 118th Pond had the highest species richness (20), mean helminth species richness (5.2), and mean helminth abundance (153.7). Frogs from Constantine East had the highest mean helminth species diversity (0.8778) and evenness (0.6033), followed by frogs from 118th Pond. In all comparisons of mean helminth community species richness, abundance, diversity, and evenness, adult frogs had significantly higher or higher values than did juveniles at each location. Jaccard's coefficients of similarity for the helminth communities for location pairs ranged from 0.545 to 0.823. Nine and 2 core helminth taxa occurred at the local and regional levels, respectively. The differences in several helminth community measures in green frogs among locations stress the importance of local ecological conditions on helminth community structure.     

The effect of diet on aerobic bacterial flora associated with intestine of Arctic charr (Salvelinus alpinus L.)

In order to extend the knowledge on the possible effect of diet on the gastrointestinal microbial community of fish, Arctic charr (Salvelinus alpinus L.) were fed diets containing high (23.7%) and low (6.4%) levels of carbohydrate. The number of viable aerobic and facultative aerobic bacteria associated with the digestive tract were not influenced by dietary regimen. A wide range of bacterial species was isolated, and the predominant bacterial species of both rearing groups were identified as Staphylococcus. There were, however, some differences in bacterial composition between the rearing groups, as well as inter-individual variations. For example, atypical Aeromonas salmonicida were isolated from the small and large intestine of two fish fed low dietary carbohydrate, while Aer. caviae-like isolates were found in the small intestine of four fish fed high carbohydrate. Non-motile Aeromonas spp. were found in the rearing group fed high dietary carbohydrate, but at low frequencies. Dietary manipulation seemed to influence the species composition of carnobacteria, Gram-positive rods, oxidase and catalase-negative and fermentative metabolism. Carnobacterium piscicola-like bacteria were only found in the small intestine, while C. mobile-like and Carnobacterium spp. were isolated from the large intestine of fish fed high carbohydrate. On the contrary, C. divergens-like isolates were found associated with the small and large intestine of fish fed low dietary carbohydrate.     

Effects of precipitation on parasite burden along a natural climatic gradient in southern Africa – implications for possible shifts in infestation patterns due to global changes

As a consequence of environmental change, it is expected that shifts in temperature and precipitation patterns will influence parasite communities and their hosts with unpredictable impact. Parasites play a vital role in ecosystems but there is only limited quantitative data which describe the effects of environmental parameters under natural conditions. We investigated the influence of rainfall, relative humidity and temperature on the prevalence, abundance and infection intensity of nematodes in southern Africa by studying the gastro‐intestinal helminth community of the striped mouse Rhabdomys pumilio. Along a precipitation gradient from the Cape of South Africa to northern Namibia we trapped 470 mice over a geographical distance of about 1400 km. Faecal egg counts of 439 sampled individuals and dissections of 161 gastro‐intestinal tracts revealed 15 different helminth species. The most abundant nematode species harboured in 62.6% of all infected mice were the oxyurid Syphacia obvelata followed jointly by two species (Heligmonina spira and Neoheligmonella capensis) of the subfamily Nippostrongylinae (43.7%). We found a significant positive correlation between mean annual precipitation (rainfall and relative humidity) and nematode infestation rates of animals and a negative correlation with temperature. In addition, we found associations between precipitation and different qualitative measurements of parasite burden (mean nematode species richness, mean number of nematode worms and infection intensity per individual host). The similarity in nematode species composition decreased with distance between all study sites. Our study indicates for the first time an association between climatic variables and parasite prevalence and abundance along a continuous natural climatic gradient in a small mammal. These results might be incorporated in the development of models which can predict possible threats for the balance of ecosystems and shifts in infestation patterns due to global changes.     

Gastrointestinal helminths of Risso's dolphin Grampus griseus from the Western Mediterranean

The gastrointestinal helminth fauna of 17 Risso's dolphins Grampus griseus (Cuvier, 1812) from the Western Mediterranean was analysed. Five helminth species were found. Adults and juveniles of Hadwenius delamurei were collected from the duodenum of 7 animals. Adults were located significantly more anteriorly than juveniles, which is compatible with a previous hypothesis that species of Hadwenius undergo an ontogenetic migration towards the anterior duodenum. Eggs from Pholeter gastrophilus appeared in 1 small cyst in the main stomach. Adults of Tetrabothrius forsteri and Trigonocotyle globicephalae were collected from the duodenum of 1 and 4 individuals, respectively. Metacestodes, Scolex pleuronectis, were found in the liver, pancreas, pyloric stomach and intestine of 13 individuals. The most favored locations were in the mucosa of the terminal colon and in anal crypts. It is likely that worms select these locations to reach the mesenteries and blubber of the anogenital area, where S. pleuronectis might become Monorygma and/or Phyllobothrium. Two individuals of Stenurus globicephalae occurred in the intestine of 1 individual, and were probably swallowed accidentally. The intestinal helminth communities of Risso's dolphin are depauperate. The parasite species found also occur in other oceanic cetaceans from the Western Mediterranean. However, H. delamurei and T. globicephalae are only shared with pilot whales Globicephala spp., which are phylogenetically closely related to Risso's dolphins.