Search results for "HELMINTH"
showing 10 items of 363 documents
ISOPOD (ASELLUS AQUATICUS) SIZE AND ACANTHOCEPHALAN (ACANTHOCEPHALUS LUCII) INFECTIONS
2007
We examined the effect of isopod size and age on the success of an acanthocephalan infection and on the effects of that infection on the growth and survival of the isopods. Groups of isopods (Asellus aquaticus) belonging to 4 size classes (juveniles, maturing adults, young adults, and older adults) were exposed to infective acanthors of Acanthocephalus lucii. At the end of the experiment, survival of the isopods, lengths of male and female isopods, and numbers of different developmental stages of A. lucii larvae in infected isopods were assessed. Acanthocephalus lucii prevalence was significantly lower in juvenile isopods than in adults. Intensity of infection increased with the size of iso…
Molecular and morphological evidence for three species of Diplostomum (Digenea: Diplostomidae), parasites of fishes and fish-eating birds in Spain
2014
Background Recent molecular studies have revealed high species diversity of Diplostomum in central and northern Europe. However, our knowledge of the distribution of Diplostomum spp. in the southern distributional range in Europe of the snail intermediate hosts (Lymnaea stagnalis and Radix spp.) is rather limited. This study aims to fill this gap in our knowledge using molecular and morphological evidence. Methods Nineteen fish species and six fish-eating bird species were sampled opportunistically in three regions (Catalonia, Extremadura and Aragon) in Spain. All isolates of Diplostomum spp. were characterised morphologically and molecularly. Partial sequences of the barcode region of the …
Analysis of the tegument of Zygocotyle lunata (Trematoda: Paramphistomidae) adults by scanning electron microscopy.
2012
Paramphistomiasis is a parasitic disease caused by various species of the Paramphistomidae. These species mainly affect domestic and wild ruminants; the economic impact of these diseases is often underestimated. Traditionally, the identification of paramphistomes has been difficult and has been based on morphological aspects such as the body shape, the position of the esophagus and cecae, or the tegumental papillae. Despite the many investigations regarding the tegumental papillae for other paramphistomes, very few efforts have been made using Zygocotyle lunata, partly because many authors differ with respect to the importance of papillae in the classification of paramphistomids. Herein, we…
ITS-2 rDNA sequencing of Gnathostoma species (Nematoda) and elucidation of the species causing human gnathostomiasis in the Americas.
2000
From several gnathostome species the complete internal transcribed spacer ITS-2 ribosomal DNA (rDNA) repeat sequence and a fragment of the 5.8S rDNA were obtained by direct polymerase chain reaction cycle-sequencing and silver-staining methods. The size of the complete ITS-1 sequence in agarose gel electrophoresis was also obtained. The ITS-2 enabled the differentiation of Gnathostoma spinigerum from Thailand and Gnathostoma binucleatum from Mexico and Ecuador and confirmed the validity of the latter. Gnathostoma turgidum, Gnathostoma sp. I (=Gnathostoma procyonis sensu Almeyda-Artigas et al., 1994), and Gnathostoma sp. II (=G. turgidum sensu Foster, 1939 pro parte), all from Mexico, proved…
Proximate factors affecting the larval life history of Acanthocephalus lucii (Acanthocephala).
2007
The growth and eventual size of larval helminths in their intermediate hosts presumably has a variety of fitness consequences. Therefore, elucidating the proximate factors affecting parasite development within intermediate hosts should provide insight into the evolution of parasite life histories. An experimental infection that resulted in heavy intensities of an acanthocephalan (Acanthocephalus lucii) in its isopod intermediate host (Asellus aquaticus) permitted the examination of parasite developmental responses to variable levels of resource availability and intraspecific competition. Isopods were infected by exposure to egg-containing fish feces, and larval infrapopulations were monitor…
Lung-worms (Nematoda: Pseudaliidae) of harbour porpoises (Phocoena phocoena) in Norwegian waters: patterns of colonization
1994
SUMMARYWe studied the component community of lung-worms of the harbour porpoise, attempting to establish the relative importance of ecological and evolutionary factors on its development. The lungs of 64 porpoises by-caught in Norwegian waters were examined for helminths. Three pseudaliid species were detected. The porpoises appear to be readily colonized by lung-worms, the structure of the component community of calves being fairly similar to that of the remainder. Prenatal and/or transmammary infections might partly account for these early infections. However, host age was correlated with the number of lung-worm species, suggesting that the lung-worms may have heteroxenous cycles similar …
Hepatic parasitosis in two wood mice, Apodemus sylvaticus (Rodentia: Muridae), due to Aonchotheca annulosa (Nematoda: Trichuridae), and Eucoleus baci…
2014
AbstractAonchotheca annulosa and Eucoleus bacillatus are two capillariin nematodes parasitizing the intestinal and stomach mucosa, respectively, of various rodent species, and two, among others, component species of the helminth fauna of the wood mouse, Apodemus sylvaticus. A capillariin each was found in the liver parenchyma of two wood mice in a post-fire regeneration enclave in Serra Calderona Natural Park (Valencian Community, Spain). Due to their location, the preliminary identification of the helminths corresponded to Calodium hepaticum, a hepatic capillariin with rodents as its main host. So far, this species had never been found in Serra Calderona. To verify the preliminary identifi…
Finding of Parastrongylus cantonensis (Chen, 1935) in Rattus rattus in Tenerife, Canary Islands (Spain).
2010
Parastrongylus cantonensis is a parasite of murid rodents that can infect humans and cause health problems as eosinophilic meningitis. Although it is endemic in south Asia, the Pacific islands, Australia, USA, and a few Caribbean islands, it has been extended to new geographical regions. In the Canary Islands (Spain) a survey of helminths of Rattus rattus, Rattus norvegicus and Mus musculus domesticus was carried out. Furthermore, five species of molluscs were examined for nematode larvae to determine whether they are potential intermediate hosts of P. cantonensis. Nematodes were found in the lungs of 15% of 67 R. rattus examined in Tenerife, one of the four studied islands, with a prevalen…
Stability of Corynosoma populations with fluctuating population densities of the seal definitive host.
2004
In theory there should be a strong coupling between host and parasite population sizes. Here, we investigated population size and structure in 3 species of acanthocephalans,Corynosoma semerme,C. strumosumandC. magdaleni, in ringed seals (Phoca hispida) from the Bothnian Bay over a period of more than 20 years. During this period, seal numbers first decreased markedly and then increased steadily; at the same time, a paratenic fish host particularly important forC. strumosumhas gradually disappeared from the bay due to decreasing salinity. We found no evidence that the mean abundance of any of the 3 acanthocephalan species changed significantly over time, nor was there any relationship betwee…
EFFECTS OF ACANTHOCEPHALUS LUCII (ACANTHOCEPHALA) ON INTERMEDIATE HOST SURVIVAL AND GROWTH: IMPLICATIONS FOR EXPLOITATION STRATEGIES
2007
Intermediate host exploitation by parasites is presumably constrained by the need to maintain host viability until transmission occurs. The relationship between parasitism and host survival, though, likely varies as the energetic requirements of parasites change during ontogeny. An experimental infection of an acanthocephalan (Acanthocephalus lucii) in its isopod intermediate host (Asellus aquaticus) was conducted to investigate host survival and growth throughout the course of parasite development. Individual isopods were infected by exposure to fish feces containing parasite eggs. Isopods exposed to A. lucii had reduced survival, but only early in the infection. Mean infection intensity w…