scholarly journals Non-resident definitive host presence is sufficient to sustain avian schistosome populations

Author(s):  
Sydney P. Rudko ◽  
Brooke A. McPhail ◽  
Ronald L. Reimink ◽  
Kelsey Froelich ◽  
Alyssa Turnbull ◽  
...  
Keyword(s):  
2019 ◽  
Vol 15 (01) ◽  
pp. 83-84
Author(s):  
B J Thakre ◽  
Joice P Joseph ◽  
Binod Kumar ◽  
Nilima Brahmbhatt ◽  
Krishna Gamit

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.


2021 ◽  
Vol 95 ◽  
Author(s):  
S.A. Kornienko ◽  
L.A. Ishigenova

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.


Author(s):  
Boris A.E.S. Savassi ◽  
Gauthier Dobigny ◽  
Jonas R. Etougbétché ◽  
Thalasse T. Avocegan ◽  
François T. Quinsou ◽  
...  

AbstractCercarial emission of schistosomes is a determinant in the transmission to the definitive host and constitutes a good marker to identify which definitive host is responsible for transmission, mainly in introgressive hybridization situations. Our goal was to test the hypothesis that micro-mammals play a role in Schistosoma haematobium, S. bovis, and/or S. haematobium x S. bovis transmission. Small mammal sampling was conducted in seven semi-lacustrine villages of southern Benin. Among the 62 animals trapped, 50 individuals were investigated for Schistosoma adults and eggs: 37 Rattus rattus, 3 Rattus norvegicus, 9 Mastomys natalensis, and 1 Crocidura olivieri. Schistosoma adults were found in four R. rattus and two M. natalensis, with a local prevalence reaching 80% and 50%, respectively. Two cercarial chronotypes were found from Bulinus globosus experimentally infected with miracidia extracted from naturally infected M. natalensis: a late diurnal and nocturnal chronotype, and an early diurnal, late diurnal, and nocturnal chronotype. The cytochrome C oxidase subunit I mtDNA gene of the collected schistosomes (adults, miracidia, and cercariae) belonged to the S. bovis clade. Eleven internal transcribed spacer rDNA profiles were found; four belonged to S. bovis and seven to S. haematobium x S. bovis. These molecular results together with the observed multi-peak chronotypes add M. natalensis as a new host implicated in S. haematobium x S. bovis transmission. We discuss the origin of the new chronotypes which have become more complex with the appearance of several peaks in a 24-h day. We also discuss how the new populations of offspring may optimize intra-host ecological niche, host spectrum, and transmission time period.


Parasitology ◽  
2020 ◽  
pp. 1-7
Author(s):  
Sajad Farahani ◽  
Per J. Palsbøll ◽  
Ido Pen ◽  
Jan Komdeur

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.


2016 ◽  
Vol 10 (2) ◽  
pp. e0004406 ◽  
Author(s):  
Roman Leontovyč ◽  
Neil D. Young ◽  
Pasi K. Korhonen ◽  
Ross S. Hall ◽  
Patrick Tan ◽  
...  
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Parasitology ◽  
1988 ◽  
Vol 97 (1) ◽  
pp. 139-147 ◽  
Author(s):  
F. Renaud ◽  
C. Gabrion

SUMMARYUsing biochemical genetic methods, we have distinguished 2 sibling species in the complex Bothrimonus nylandicus (Schneider, 1902), which infest 2 congeneric species of sole (Solea lascaris and Solea impar) on European coasts (Atlantic and Mediterranean). Neither of the parasite species is specific for either of the sole species, but one of them is present all year round, whereas the other is absent in the autumn and winter and only appears in the spring, subsequently disappearing at the end of the summer. Only S. impar lives in the Mediterranean, and is equally infested by both cestodes, whereas both species occur in the Atlantic and each of them is preferentially infested by 1 species of cestode. The shortness of the adult stage of the parasite in the definitive host and the presence of 2 life-cycles associated with competition between the 2 hosts in the Atlantic could be responsible for the biological differences observed and for maintaining the sibling species in sympatry.


Parasitology ◽  
2001 ◽  
Vol 122 (4) ◽  
pp. 483-489 ◽  
Author(s):  
B. S. DEZFULI ◽  
L. GIARI ◽  
R. POULIN

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.


2020 ◽  
Vol 3 (12) ◽  
pp. 83-86
Author(s):  
Shаvkat Avezimbetov ◽  
Odilbek Dosumbetov

Fastioliosis in the Republic of Karakalpakstan in acute, chronic and mixed course, acute course of F. gigantica-induced fasciolosis in sheep, clinical signs of fasciolosis, adult fasciolia, definitive host-infected fasciola larvae,  possible factors, diagnosis, results of complete dissection of the liver in animals that died from the disease, drugs for the treatment of fasciolosis are described.


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