Intermediate hosts as source communities

1993 ◽  
Vol 71 (7) ◽  
pp. 1358-1363 ◽  
Author(s):  
Albert O. Bush ◽  
Richard W. Heard Jr. ◽  
Robin M. Overstreet
Keyword(s):  
Definitive Host ◽  
Sympatric Species ◽  
Community Level ◽  
Host Feeding ◽  
Helminth Parasites ◽  
Intermediate Hosts ◽  
Cerithidea Californica ◽  
Helminth Communities ◽  
Different Populations

We describe helminth communities in two sympatric species of intertidal crabs (Pachygrapsus transversus and Panopeus lacustris) that serve as intermediate hosts for helminth parasites. We suggest that a single definitive host feeding briefly on Pachygrapsus transversus may be colonized simultaneously by up to six species of microphallid trematodes and that infrapopulations can increase rapidly by a definitive host feeding on Panopeus lacustris. Therefore, we argue that consideration of colonization processes in definitive hosts may be a crucial underpinning to many community-level studies. We show that, in Florida, colonization of Cerithidea scalariformis by miracidia is markedly different from observations made on Cerithidea californica in California. Also, different populations of C. scalariformis are highly variable in the helminths they support. We conclude that community-level studies on invertebrate intermediate hosts may be easier and more informative than similar studies on definitive hosts.

Costs of intraspecific and interspecific host sharing in acanthocephalan cystacanths

Parasitology ◽  
2001 ◽  
Vol 122 (4) ◽  
pp. 483-489 ◽  
Author(s):  
B. S. DEZFULI ◽  
L. GIARI ◽  
R. POULIN
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Interspecific Interactions ◽  
Sympatric Species ◽  
Competitive Interactions ◽  
Host Size ◽  
Intermediate Hosts ◽  
Transmission Success ◽  
Additional Costs ◽  
Net Benefits

Larval helminths often share individual intermediate hosts with other larval worms of the same or different species. In the case of immature acanthocephalans capable of altering the phenotype of their intermediate hosts, the benefits or costs of host sharing can be evaluated in terms of increased or decreased probability of transmission to a suitable definitive host. Competitive interactions among the immature stages of acanthocephalans within the intermediate host could create additional costs of host sharing, however. The effects of intraspecific and interspecific interactions were measured in 3 sympatric species of acanthocephalans exploiting a population of the amphipod Echinogammarus stammeri in the River Brenta, Italy. The strength of interactions was assessed from differences in the size achieved by infective cystacanths in the intermediate host. The size of Pomphorhynchus laevis cystacanths was not correlated with host size, whereas the size of Acanthocephalus clavula and Polymorphus minutus cystacanths increased with host size. Reductions in cystacanth size caused by intraspecific competition were only detected in P. laevis, but may also occur in both A. clavula and P. minutus. When co-occurring in the same amphipod with cystacanths of A. clavula, cystacanths of P. laevis attained a smaller size than when they occurred on their own. This effect was not reciprocal, with the size of A. clavula cystacanths not being affected. This supports earlier suggestions that it is adaptive for A. clavula to associate with P. laevis in amphipod intermediate hosts, with both species going to the same fish definitive hosts. In contrast, cystacanths of P. laevis achieved their largest size when they co-occurred in an amphipod with a cystacanth of P. minutus, which has a different definitive host (i.e. birds). These findings suggest that the net benefits of sharing an intermediate host can only be estimated by taking into account both the effects on transmission success and the consequences for cystacanth development.

Taeniasis in a German Shepherd Pup: A Case Report

2019 ◽  
Vol 15 (01) ◽  
pp. 83-84
Author(s):  
B J Thakre ◽  
Joice P Joseph ◽  
Binod Kumar ◽  
Nilima Brahmbhatt ◽  
Krishna Gamit
Keyword(s):  
Case Report ◽  
Life Cycle ◽  
Definitive Host ◽  
Gastrointestinal Diseases ◽  
Intermediate Hosts ◽  
German Shepherd ◽  
Taenia Hydatigena ◽  
Taenia Multiceps ◽  
Taenia Crassiceps ◽  
Dipylidium Caninum

Taenia spp. are long, segmented, parasitic tapeworms and are relatively uncommon in canine gastrointestinal diseases compared to other tapeworms like Dipylidium caninum. These parasites have an indirect life cycle, cycling between definitive and intermediate hosts. Dogs act as definitive hosts of different species of Taenia including Taenia multiceps, Taenia serialis, Taenia crassiceps, Taenia hydatigena, Taenia pisiformis, etc. Taenia multiceps is of greatest zoonotic relevance in human. In the definitive host, it causes only mild infection. Larvae are more likely to cause disease than adult tapeworms. Taeniasis in pets should be cautiously handled because of its zoonotic importance. This communication reports a case of 3 months old pup suffering from Taenia infection that was successfully managed with a combination of praziquantel and fenbendazole.

Distribution of the cestode Urocystis prolifer Villot, 1880 (Cyclophyllidea: Hymenolepididae) in the Palaearctic and new data on its postembryonic development

2021 ◽  
Vol 95 ◽  
Author(s):  
S.A. Kornienko ◽  
L.A. Ishigenova
Keyword(s):  
Host Specificity ◽  
Geographical Distribution ◽  
Experimental Infection ◽  
Definitive Host ◽  
Intestinal Parasite ◽  
Geographic Area ◽  
Postembryonic Development ◽  
Generic Diagnosis ◽  
Intermediate Hosts ◽  
Very High

Abstract Urocystis prolifer Villot, 1880 is an intestinal parasite of Sorex spp. In the Palaearctic. There are significant differences in the descriptions of both adults and stages of ontogenesis of U. prolifer as described by various authors. The experimental infection of intermediate hosts with cestodes has been conducted. An overview of the geographical distribution, infestation of the definitive hosts and the development of the metacestode stages of U. prolifer are presented. The cestode is characterized by an extensive geographic area in the Palaearctic, wide host specificity and very high rates of infection of its definitive host. Urocystis prolifer has been recorded mostly in the taiga and forest zones of Palaearctic. Fourteen species of Sorex were registered as the definitive host. Redescription of U. prolifer and an amended generic diagnosis are provided. A complete description of the ontogeny from oncosphere to fully developed metacestode is given. Features of development of the metacestode are an asexual larval reproduction, the absence of the anterior and posterior obturator valve in the cyst of the fully developed urocyst, as well as excretory bodies.

scholarly journals Effects of parasites upon non-host predator avoidance behaviour in native and invasive gammarids

Parasitology ◽  
2020 ◽  
pp. 1-7
Author(s):  
Sajad Farahani ◽  
Per J. Palsbøll ◽  
Ido Pen ◽  
Jan Komdeur
Keyword(s):  
Invasive Species ◽  
Definitive Host ◽  
Predator Avoidance ◽  
Gasterosteus Aculeatus ◽  
Chemical Cues ◽  
Critical Role ◽  
Fundamental Question ◽  
Intermediate Hosts ◽  
Gammarus Fossarum ◽  
Acanthocephalan Parasite

Abstract The acanthocephalan parasite, Polymorphus minutus, manipulates its intermediate hosts' (gammarids) behaviour, presumably to facilitate its transmission to the definitive hosts. A fundamental question is whether this capability has evolved to target gammarids in general, or specifically sympatric gammarids. We assessed the responses to chemical cues from a non-host predator (the three-spined sticklebacks Gasterosteus aculeatus) in infected and non-infected gammarids; two native (Gammarus pulex and Gammarus fossarum), and one invasive (Echinogammarus berilloni) species, all sampled in the Paderborn Plateau (Germany). The level of predator avoidance was assessed by subjecting gammarids to choice experiments with the presence or absence of predator chemical cues. We did not detect any behavioural differences between uninfected and infected G. pulex and E. berilloni, but an elevated degree of predator avoidance in infected G. fossarum. Avoiding non-host predators may ultimately increase the probability of P. minutus' of predation by the definitive host. Our results suggested that P. minutus' ability to alter the host's behaviour may have evolved to specifically target sympatric gammarid host species. Uninfected gammarids did not appear to avoid the non-host predator chemical cues. Overall the results also opened the possibility that parasites may play a critical role in the success or failure of invasive species.

Polychaetes as Intermediate Hosts of Helminth Parasites of Vertebrates: A Review

1971 ◽  
Vol 28 (10) ◽  
pp. 1385-1392 ◽  
Author(s):  
L. Margolis
Keyword(s):  
Helminth Parasites ◽  
Intermediate Hosts ◽  
Larval Stages ◽  
Aquatic Vertebrates

The role of polychaetes as intermediate hosts of helminth parasites of aquatic vertebrates is reviewed. Some 18–20 species of trematodes and three or four each of cestodes and nematodes are known to have larval stages in these annelids. There are no records of acanthocephalan larvae from polychaetes. Trematoda use polychaetes as first (three species) or second intermediate hosts. The polychaete hosts are found among various genera of Errantia, Sedentaria, and Myzostomida. Definitive hosts are mainly fishes, with a few species of trematodes and one of cestodes developing in birds, and apparently one genus of nematodes (two species) maturing in the lungs of seals. A list of polychaetes and their larval helminth parasites is given.

scholarly journals Sarcocystis Attenuati N. Sp. (Apicomplexa: Sarcocystidae) Infecting the Asian Gray Shrew, Crocidura Attenuata (Insectivora: Soricidae), in China

2021 ◽  
Author(s):  
junjie hu ◽  
Jun Sun ◽  
Yanmei Guo ◽  
Hongxia Zeng ◽  
Yunzhi Zhang ◽  
...  
Keyword(s):  
Host Specificity ◽  
Definitive Host ◽  
18S Rdna ◽  
Common Species ◽  
Molecular Characteristics ◽  
Intermediate Hosts ◽  
Parasite Life Cycle ◽  
Rdna Sequences ◽  
Transmission Electron ◽  
18S Rdna Sequences

Abstract Background: There are limited data on Sarcocystis in insectivores. The Asian gray shrew, Crocidura attenuata, is one of the most common species of insectivores in the family Soricidae distributed in South Asia and Southeast Asia. To date, Sarcocystis has never been recorded in this host.Methods: Tissues from 42 Asian gray shrews were collected in China in 2017 and 2018. Sarcocysts were observed using light (LM) and transmission electron microscopy (TEM). To complete the parasite life cycle, muscle tissues of the host infected with sarcocysts were force-fed to two beauty rat snakes, Elaphe taeniura. Individual sarcocysts from different Asian gray shrews and oocysts/sporocysts isolated from the small intestines and feces of the experimental snakes were selected for DNA extraction, and seven genetic markers, including two nuclear loci (18S rDNA and ITS1), three mitochondrial genes (cox1, cox3 and cytb), and two apicoplastic genes (rpoB and clpC), were amplified, sequenced and analyzed.Results: Sarcocysts were found in 17 of 42 (40.5%) Asian gray shrews. Under LM, the microscopic sarcocysts were exhibited saw-tooth-like protrusions measuring 3.3–4.5 μm. Ultrastructurally, the sarcocyst wall contained numerous lancet- or leaf-like villous protrusions, similar to type 9h. The experimental beauty rat snakes shed oocysts/sporcysts measuring 11.9–16.7 × 9.2–10.6 μm with a prepatent period of 10 to 11 days. Comparing these sequences with those previously deposited in GenBank revealed that the 18S rDNA sequences and cox1 sequences shared the highest similarity with those of S. scandentiborneensis recorded in tree shrews, Tuaia minor and T. tana (i.e., 97.6–98.3% and 100% identity, respectively). Phylogenetic analysis based on 18S rDNA, ITS1 or cox1 sequences revealed that this parasite formed an independent clade with Sarcocystis spp. that utilize small animals as intermediate hosts and snakes as the known or presumed definitive host. On the basis of morphological and molecular characteristics and host specificity, the parasite was proposed as a new species, named S. attenuati.Conclusions: Sarcocysts were recorded in Asian gray shrews for the first time. The sarcocysts were characterized morphologically and molecularly. The 18S rDNA and cox1 sequences of S. attenuati, named in the present study, shared the highest identities with those of S. scandentiborneensis. However, the sarcocysts of the two species of Sarcocystis were quite different under LM and TEM. Based on experimental infection, beauty rat snakes have been proven to be a definitive host of S. attenuati. As more species of Sarcocystis from insectivores and other small mammals are properly morphologically and molecularly characterized, we may gain a better understanding of the biodiversity, host specificity and evolution of Sarcocystis in the future.

Population dynamics of two species of intestinal helminth in oystercatchers (Haematopus ostralegus)

1995 ◽  
Vol 73 (2) ◽  
pp. 296-308 ◽  
Author(s):  
C. P. Goater ◽  
J. D. Goss-Custard ◽  
C. R. Kennedy
Keyword(s):  
Paratenic Host ◽  
Feeding Preference ◽  
Host Population ◽  
Intestinal Helminth ◽  
Host Feeding ◽  
Intestinal Helminths ◽  
Host Age ◽  
Intermediate Hosts ◽  
Second Intermediate Host ◽  
Haematopus Ostralegus

The cestode Micrasomacanthus rectacantha and the trematode Psilostomum brevicolle are the two most common intestinal helminths of oystercatchers, Haematopus ostralegus, on the Exe estuary, England. Each was present in 57 of 60 birds, in numbers ranging from 1 to 9833 and from 1 to 182, respectively. Cockles (Cerastoderma edule) were used as paratenic host by M. rectacantha and as second intermediate host by P. brevicolle. Over 90% of the transmission of M. rectacantha from intermediate hosts occurred in winter, between cockles and juvenile birds. Exposure to M. rectacantha was highest in cockles from muddy sites, where up to 80% of older cockles were infected with 1–14 larvae. Exposure to P. brevicolle was similarly high at one sandy site. Juveniles also made up > 90% of the birds present on the estuary in summer, when significantly more worms were gravid. Estimates based on the numbers of uterine eggs per individual P. brevicolle showed that 8 % of the total Exe population of oystercatchers (ca. 200) contributed 51% of the eggs to the estuary. The results implicate host age, host feeding preference, and host population structure as important factors determining variation in helminth abundance in birds.

The influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum

1999 ◽  
Vol 73 (2) ◽  
pp. 143-145 ◽  
Author(s):  
A.M. McCarthy
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Host Species ◽  
Post Infection ◽  
Rana Temporaria ◽  
Biomphalaria Glabrata ◽  
Reproductive Status ◽  
Intermediate Hosts ◽  
Potential Influence ◽  
Second Intermediate Host

The potential influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum to the definitive host Anas platyrhynchos was examined experimentally. Echinoparyphium recurvatum metacercarial cysts were obtained from the following experimentally infected second intermediate hosts 14 days post expsoure to cercariae: Lymnaea peregra; Physa fontinalis; L. stagnalis;Planorbis planorbis; Biomphalaria glabrata; tadpoles of the amphibian Rana temporaria. Metacercarial cysts from each of these hosts were fed, in doses of 50 cysts per individual, to separate groups composed of between four and eight, 3-day-old A. platyrhynchos ducklings. All A. platyrhynchos were necropsied 15 days post-infection and the number, size, and reproductive status of E. recurvatum worms in the intestine was recorded. Analyses of variance on the number (transformed log (x + 1)) and size of worms revealed no significant differences in worms originating from metacercariae formed in the different second intermediate hosts (worm number P > 0.05, and worm size P > 0.05). All worms recovered were found to be gravid. It is therefore concluded that the species of second intermediate host utilized does not influence the infectivity of the metacercarial cyst of E. recurvatum, nor the subsequent establishment and reproductive status of the parasite in A. platyrhynchos.

The helminth parasites of two sympatric species of the genus Apodemus (Rodentia, Muridae) from south-eastern Slovakia

2010 ◽  
Vol 55 (4) ◽  
Author(s):  
Jarmila Ondríková ◽  
Dana Miklisová ◽  
Alexis Ribas ◽  
Michal Stanko
Keyword(s):  
Sympatric Species ◽  
Helminth Fauna ◽  
Hymenolepis Diminuta ◽  
Individual Species ◽  
Helminth Parasites ◽  
Heligmosomoides Polygyrus ◽  
Mean Intensity ◽  
Host Ecology ◽  
Taenia Taeniaeformis ◽  
Rodent Populations

AbstractThe helminths of two sympatric species of rodents, the striped field mouse Apodemus agrarius and the yellow-necked mouse, Apodemus flavicollis from Slovakia were studied to determine whether there are similarities in the composition of the helminth fauna of two closely related host species living in the same area. A total of twelve species of helminths were identified in these rodent populations, including Brachylaima sp. (Trematoda); Hymenolepis diminuta (Rudolphi, 1819), Mesocestoides sp. larvae, Rodentolepis fraterna (Stiles, 1906), Rodentolepis straminea (Goeze, 1782), Skrjabinotaenia lobata (Baer, 1925), Taenia taeniaeformis larvae (Batsch, 1786) (Cestoda); Aonchotheca annulosa (Dujardin, 1845), Heligmosomoides polygyrus (Dujardin, 1845), Heterakis spumosa Schneider, 1866, Mastophorus muris (Gmelin, 1790) and Syphacia stroma (Linstow, 1884) (Nematoda). In A. agrarius, H. polygyrus was the most prevalent, as well as the most abundant helminth, but R. fraterna was the species with the highest mean intensity. In contrast, S. stroma dominated the A. flavicollis helminth fauna with the highest prevalence, mean abundance and mean intensity. Both rodent populations harboured nine helminth species, although the mean individual species richness was significantly higher in A. agrarius than in A. flavicollis. The analysis of helminth diversity at both component and infracommunity levels revealed differences between the two rodent populations, which are most likely attributable to the specific host ecology.

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