scholarly journals The helminth infracommunities of the wood mouse (Apodemus sylvaticus) two years after the fire in Mediterranean forests

2013 ◽  
Vol 50 (1) ◽  
pp. 27-38 ◽  
Author(s):  
I. Torre ◽  
A. Arrizabalaga ◽  
C. Feliu ◽  
A. Ribas

AbstractParasites have been recognized as indicators for natural or man-induced environmental stress and perturbation. In this article, we investigated the role of two non-exclusive hypotheses on the response of helminths of wood mice to fire perturbation: 1) a reduction of the helminth infracommunity (species richness) in post-fire areas due to the temporal lack of worms with indirect (complex) life cycles linked to intermediate hosts that are more specialized than the final host, and 2) an increase of the abundance of helminths with direct (simple) life cycles as a response of increasing abundances of the final host, may be in stressful conditions linked to the post-fire recolonization process.We studied the helminth infracommunities of 97 wood mice in two recently burned plots (two years after the fire) and two control plots in Mediterranean forests of NE Spain. Species richness of helminths found in control plots (n = 14) was twice large than in burned ones (n = 7). Six helminth species were negatively affected by fire perturbation and were mainly or only found in unburned plots. Fire increased the homogeneity of helminth infracommunities, and burned plots were characterised by higher dominance, and higher parasitation intensity. We found a gradient of frequency of occurrence of helminth species according to life cycle complexity in burned areas, being more frequent monoxenous (66.6 %), than diheteroxenous (33.3 %) and triheteroxenous (0 %), confirming the utility of helminths as bioindicators for ecosystem perturbations. Despite the short period studied, our results pointed out an increase in the abundance and prevalence of some direct life cycle helminths in early postfire stages, whereas indirect life cycle helminths were almost absent. A mismatch between the final host (that showed a fast recovery shortly after the fire), and the intermediate hosts (that showed slow recoveries shortly after the fire), was responsible for the loss of half of the helminth species.

1998 ◽  
Vol 76 (6) ◽  
pp. 1198-1203 ◽  
Author(s):  
SR Martorelli ◽  
F Cremonte

This is the first record of cercariae of Monascus filiformis (Rudolphi, 1819) and of Chaetognatha as a secondintermediate host in the southwest Atlantic Ocean. The morphology of the sporocyst and cercaria from Nucula obliqua (Bivalvia:Nuculidae) and a full description of the metacercaria from hydromedusae are given. The life cycle of M. filiformis involves threehosts. The bivalve N. obliqua is the first intermediate host, Chaetognatha and medusae are the second intermediate hosts, and thejurel Trachurus lathami (Pisces: Carangidae) is the final host. The life cycle of M. filiformis occurs in shallow waters in theArgentine Sea and differs from Køie’s experimental scheme for the North Sea in the addition of planktonic invertebrates assecond intermediate hosts. The life cycle proposed here follows the general pattern given for the family Fellodistomidae.


Parasitology ◽  
1983 ◽  
Vol 86 (1) ◽  
pp. 147-160 ◽  
Author(s):  
J. H. Ali ◽  
J. Riley

SUMMARYThe life-cycles of two closely related cephalobaenid pentastomids, Raillietiella gehyrae and Raillietiella frenatus, which utilize geckos as definitive hosts and cockroaches as intermediate hosts, have been investigated in detail. Early development in the fat-body of cockroaches involves 2 moults to an infective, 3rd-stage larva which appears from 42–44 days post-infection. Complete development in geckos involves a further 5 moults in the case of males and 6 for females. Males mature precociously and copulation is a once-in-a-lifetime event which occurs around day 80 post-infection when both sexes are the same size but the uterus of the female is undeveloped. Sperm, stored in the spermathecae, is used to fertilize oocytes which slowly accumulate in the developing saccate uterus. Patency commences when the uterus carries approximately 4000–5500 eggs but only 25–36 % of these contain fully developed primary larvae. Since only mature eggs are deposited, we postulate that the vagina (?) of the female must be equipped with a selective filter that allows through large eggs but retains smaller, immature eggs. Thus the only limit on fecundity is the total number of sperms in the spermathecae and this is precisely the same factor that constrains egg production in the advanced order Porocephalida.


2019 ◽  
Vol 53 (1) ◽  
pp. 13-22 ◽  
Author(s):  
E. P. Zhytova ◽  
L. D. Romanchuk ◽  
S. V. Guralska ◽  
O. Yu. Andreieva ◽  
M. V. Shvets

Abstract This is the first review of life cycles of trematodes with parthenitae and larvae in freshwater gastropods from forest biocoenoses of Ukrainian Polissia. Altogether 26 trematode species from 14 families were found circulating in 13 ways in molluscs from reservoirs connected with forest ecosystems of the region. Three-host life cycle is typical of 18 trematode species, two-host life cycle has found in 7 species, and four-host cycles has found in one species. Alaria alata Goeze, 1782, has three-host (Shults, 1972) and four-host cycles. Opisthioglyphe ranae (Froehlich, 1791) can change three-host life cycle to two-host cycle replacing the second intermediate host (Niewiadomska et al., 2006) with the definitive host. Species with primary two-host life cycle belong to Notocotylidae Lühe, 1909, Paramphistomidae Fischoeder, 1901 and Fasciolidae Railliet, 1758 families. Trematodes with three-host cycle have variable second intermediate hosts, including invertebrates and aquatic or amphibious vertebrates. Definitive hosts of trematodes are always vertebrates from different taxonomic groups. The greatest diversity of life cycles is typical for trematodes of birds. Trematodes in the forest biocoenoses of Ukrainian Polissia infect birds in six ways, mammals in three, amphibians in four, and reptiles in one way. The following species have epizootic significance: Liorchis scotiae (Willmott, 1950); Parafasciolopsis fasciolaemorpha Ejsmont, 1932; Notocotylus seineti Fuhrmann, 1919; Catatropis verrucosa (Frölich, 1789) Odhner, 1905; Cotylurus cornutus (Rudolphi, 1808); Echinostoma revolutum (Fröhlich, 1802) Dietz, 1909; Echinoparyphium aconiatum Dietz, 1909; Echinoparyphium recurvatum (Linstow, 1873); Hypoderaeum conoideum (Bloch, 1782) Dietz, 1909; Paracoenogonimus ovatus Kasturada, 1914; Alaria alata Goeze, 1782.


2020 ◽  
Vol 14 (4) ◽  
pp. 11-23
Author(s):  
F. J. Akramova ◽  
M. Sh. Toremuratov ◽  
U. A. Shakarbaev ◽  
L. A. Rakhmonova ◽  
D. A. Azimov ◽  
...  

The purpose of the research is studying current fauna of helminths in wild artiodactyls and analysis of their ecological relationships with populations of representatives of the Artiodactyla in biogeocenoses of Karakalpakstan.Materials and methods. Wild populations of artiodactyls were studied in 2016–2020 in the ecosystems of the Kyzyl Kum, Ustyurt and the lower reaches of the Amu Darya, including the drained bottom of the Aral Sea. Some killed animals (the saiga, Persian gazelle, and Bokharan deer) seized from poachers, as well as those killed by predators and feral dogs in the sanctuaries and reserves of Karakalpakstan were used to collect helminthological material. Wild boars were examined after shooting during the hunting season. A total of 11 saigas, 13 Persian gazelles, 7 Bokharan deer and 16 wild boars, and 213 fecal samples from these animals were examined. The studies were carried out using generally accepted methods of dissection (Skryabin, 1928; Ivashkin et al., 1971) and ovoscopy of animal feces. For a comparative analysis of helminth fauna of the study animals, we used previously collected (1959–1978) parasites from the wild boar, saiga, Persian gazelle and Bokharan deer in Karakalpakstan.Results and discussion. We have found that the fauna of the Artiodactyla is represented by the following 5 species in the biogeocenosis of Karakalpakstan: Sus scrofa nigripes Blan., Cervis elaphus bactrianus Lydek., Gazella subgutturosa Gueld., Saiga tatarica Linn., and Ovis orientalis arcal Gmel., in which we identified 26 helminth species classified as Cestoda, Trematoda and Nematoda. Cestodes are represented by 6 species, trematodes by 2 species, and nematodes by 18 species. The helminth species composition of the study animals is 14 species in pigs, 11 species in Bokharan deer, 13 species in saigas and 14 species in Persian gazelles. Representatives of the genera Taenia, Echinococcus, Fasciola, Schistosoma, Gongylonema and Setaria are common to these animal species. By nature of the biological cycle, the helminths of the study artiodactyls recorded by us can be divided into two groups: monoxenous and heteroxenous. Monoxenous parasites include representatives of the Trichocephalidae (3 species), Trichostrongylidae (2 species), Dictyocaulidae (2 species), Syphaciidae (1 species), and Ascarididae (1 species), whose life cycles proceed without changing hosts. Eighteen species of representatives of cestodes (6 species), trematodes (2 species) and nematodes (10 species) are developed with the involvement of intermediate hosts.


Parasitology ◽  
1933 ◽  
Vol 25 (4) ◽  
pp. 518-545 ◽  
Author(s):  
S. Benton Talbot

1. The life histories of Lechriorchis primus Stafford, L. tygarti n.sp. and Caudorchis eurinus n.gen. et sp. have been experimentally completed in three hosts, the first complete life histories to be worked out for species of the subfamily Reniferinae.2. The definitive hosts of the three forms were found to be two species of garter snakes, Thamnophis sauritus and T. sirtalis.3. Three species of snails, Physella gyrina, P. parkeri, and P. ancillaria, have been found to serve as the first intermediate host in the life cycles of Lechriorchis primus and Caudorchis eurinus n.gen. et sp., and two species of snails, Physella gyrina and P. heterostropha, in the life cycle of Lechriorchis tygarti n.sp.4. The tadpoles of two species of frogs, Rana clamitans and R. pipiens, were found to serve as the second intermediate hosts in the life cycles of all three trematodes. The cercariae penetrate larvae of Triturus and small fish, but live only a short time in these animals.5. Every stage in the life history of Lechriorchis primus, including egg, miracidium, mother sporocyst, daughter sporocyst, cercaria, metacercaria, and developmental stages in the definitive host, has been described in detail.6. The mother sporocyst of forms having a stylet cercaria is described for the first time.7. The flame cell pattern of the cercariae of L. primus, L. tygarti n.sp., and Caudorchis eurinus n.gen. et sp. has been determined to be of the “2 × 6 × 3’ type. Also the adult stage of C. eurinus was determined to have the same type.8. It has been pointed out that the life histories of the members of the subfamily are uniform in that their life history stages display a remarkable similarity.9. It has been suggested that this uniform type of life cycle and remarkable similarity of larval stages offer the most logical basis for establishing the subfamily Reniferinae as a natural group.


2017 ◽  
Vol 91 (6) ◽  
pp. 647-656 ◽  
Author(s):  
I. Blasco-Costa ◽  
R. Poulin

AbstractMany helminth taxa have complex life cycles, involving different life stages infecting different host species in a particular order to complete a single generation. Although the broad outlines of these cycles are known for any higher taxon, the details (morphology and biology of juvenile stages, specific identity of intermediate hosts) are generally unknown for particular species. In this review, we first provide quantitative evidence that although new helminth species are described annually at an increasing rate, the parallel effort to elucidate life cycles has become disproportionately smaller over time. We then review the use of morphological matching, experimental infections and genetic matching as approaches to elucidate helminth life cycles. Next we discuss the various research areas or disciplines that could benefit from a solid knowledge of particular life cycles, including integrative taxonomy, the study of parasite evolution, food-web ecology, and the management and control of parasitic diseases. Finally, we end by proposing changes to the requirements for new species descriptions and further large-scale attempts to genetically match adult and juvenile helminth stages in regional faunas, as part of a plea to parasitologists to bring parasite life-cycle studies back into mainstream research.


2020 ◽  
Vol 25 (11) ◽  
pp. 261-267
Author(s):  
Paul A. M. Overgaauw

In industrialised countries, dogs and cats are more often fed raw meat-based diets. There are microbial hazards associated with raw meat and these can introduce the risk of insufficient nutrition, as a result of nutritional imbalances and deficiencies. A literature review has been carried out to evaluate the risks of parasite infections in companion animals resulting from raw meat-based diets. Parasites present in raw meat use dogs and cats as part of their life cycle, these include protozoa such as Toxoplasma, Sarcocystis, Cystoisospora, Neospora and Hammondia; the nematodes Toxocara spp. and Trichinella; and the tapeworms Taenia spp., Echinococcus granulosus and E. multilocularis. Because of the lack of prevalence data, a valuable risk analysis is difficult. However, the life cycles demonstrate that eating raw meat-based diets and prey animals, can be a route of infection. Such agents can also be present in slaughtered animals. Infections can induce disease in intermediate hosts, but also in humans and other animal species, as an environment can be contaminated with oocysts or eggs. Several parasites can be transmitted via the alimentary route when raw meat-based diets are fed to companion animals. The best prevention method is to feed your companion animals commercial food or to cook meat and organs before feeding.


2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Spencer Froelick ◽  
Laura Gramolini ◽  
Daniel P. Benesh

Parasitic worms (i.e. helminths) commonly infect multiple hosts in succession before reproducing. At each life cycle step, worms may fail to infect the next host, and this risk accumulates as life cycles include more successive hosts. Risk accumulation can be minimized by having high establishment success in the next host, but comparisons of establishment probabilities across parasite life stages are lacking. We compiled recovery rates (i.e. the proportion of parasites recovered from an administered dose) from experimental infections with acanthocephalans, cestodes and nematodes. Our data covered 127 helminth species and 16 913 exposed hosts. Recovery rates increased with life cycle progression (11%, 29% and 46% in first, second and third hosts, respectively), because larger worm larvae had higher recovery, both within and across life stages. Recovery declined in bigger hosts but less than it increased with worm size. Higher doses were used in systems with lower recovery, suggesting that high doses are chosen when few worms are expected to establish infection. Our results indicate that growing in the small and short-lived hosts at the start of a complex life cycle, though dangerous, may substantially improve parasites' chances of completing their life cycles.


Parasitology ◽  
2009 ◽  
Vol 136 (7) ◽  
pp. 793-804 ◽  
Author(s):  
J. M. BEHNKE ◽  
C. EIRA ◽  
M. ROGAN ◽  
F. S. GILBERT ◽  
J. TORRES ◽  
...  

SUMMARYWe analysed 3 independently collected datasets of fully censused helminth burdens in wood mice,Apodemus sylvaticus, testing thea priorihypothesis of Behnkeet al.(2005) that the presence of the intestinal nematodeHeligmosomoides polygyruspredisposes wood mice to carrying other species of helminths. In Portugal, mice carryingH. polygyrusshowed a higher prevalence of other helminths but the magnitude of the effect was seasonal. In Egham, mice withH. polygyrusshowed a higher prevalence of other helminth species, not confounded by other factors. In Malham Tarn, mice carryingH. polygyruswere more likely to be infected with other species, but only among older mice. Allowing for other factors, heavy residualH. polygyrusinfections carried more species of other helminths in both the Portugal and Egham data; species richness in Malham was too low to conduct a similar analysis, but asH. polygyrusworm burdens increased, so the prevalence of other helminths also increased. Our results support those of Behnkeet al.(2005), providing firm evidence that at the level of species richness a highly predictable element of co-infections in wood mice has now been defined: infection withH. polygyrushas detectable consequences for the susceptibility of wood mice to other intestinal helminth species.


2019 ◽  
Author(s):  
Chloé Suzanne Berger ◽  
Nadia Aubin-Horth

ABSTRACTParasites with complex life cycles have been proposed to manipulate the behaviour of their intermediate hosts to increase the probability of reaching their final host. The cause of these drastic behavioural changes could be manipulation factors released by the parasite in its environment (the secretome), but this has rarely been assessed. We studied a non-cerebral parasite, the cestode Schistocephalus solidus, and its intermediate host, the threespine stickleback (Gasterosteus aculeatus), whose response to danger becomes significantly diminished when infected. These altered behaviours appear only during late infection, when the worm is ready to reproduce in its final avian host. Sympatric host-parasite pairs show higher infection success for parasites, suggesting that the secretome effects could differ for allopatric host-parasite pairs with independent evolutionary histories. We tested the effects of secretome exposure on behaviour by using secretions from the early and late infection of S. solidus and by injecting them in healthy sticklebacks from a sympatric and allopatric population. Contrary to our prediction, secretome from late infection worms did not result in more risky behaviours, but secretome from early infection resulted in more cautious hosts, only in fish from the allopatric population. Our results suggest that the secretome of Schistocephalus solidus contains molecules that can affect host behaviour, that the causes underlying the behavioural changes in infected sticklebacks are multifactorial, and that local adaptation between host-parasite pairs may extend to the response to the parasite’s secretome content.


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