The lungworm Protostrongylus boughtoni (Nematoda, Metastrongyloidea) in gastropod intermediate hosts and the snowshoe hare, Lepus americanus

1990 ◽  
Vol 68 (12) ◽  
pp. 2567-2575 ◽  
Author(s):  
Robert A. Kralka ◽  
W. M. Samuel

Natural infections of Protostrongylus boughtoni in intermediate and definitive hosts were examined in Boreal Forest habitats of north central Alberta. Vertigo gouldi was the major intermediate host. Prevalence and intensity of P. boughtoni larvae in V. gouldi were similar among habitats, among size classes of V. gouldi, and temporally. Prevalence of P. boughtoni in adult snowshoe hares was 100%; mean intensity varied monthly at relatively low levels. Juvenile snowshoe hares became infected within a month of birth; intensities increased to relatively high within 3 months and then declined, indicating development of an immune response or decreased exposure to infected snails. No evidence was found for transplacental transmission. Relative rates of flow of P. boughtoni were calculated to determine the importance of snail species and habitat types in transmission of the parasite. Vertigo gouldi accounted for nearly all flow from snails to hares, and most of the flow from snails to hares occurred in dry coniferous and mixed wood habitats.

2019 ◽  
Vol 56 (1) ◽  
pp. 81-86
Author(s):  
V. G. V. Paller ◽  
J. R. M. Macaraig ◽  
R. T. Verona ◽  
L. A. Estaño

SummaryFreshwater snails serve as one of trematodes’ intermediate hosts. Previous studies on trematode larval stages in the Philippines have largely focused on species with public health importance. This study sought to investigate the prevalence of cercarial morphotypes in several freshwater snail species found in different habitat types (rice field, irrigation canals, and residential area) in selected agricultural areas in Los Baños and Bay in Laguna. Cercarial emergence was induced through exposure to artificial light. A total of 2,720 freshwater snails were collected and were represented by seven species, namely, Melanoides tuberculata Muller 1774 (n = 1229), Radix quadrasi von Moellendorf (n = 630), Tarebia granifera Lamarck, 1816 (n = 417), Pomacea canaliculata Lamarck 1819 (n = 257), Vivipara angularis philippinensis Nevill (n = 18), Stenomelania sp. (n = 104), Thiara scabra Muller 1774 (n = 65). A 2.57 % over-all prevalence was recorded; the infected snail species were M. tuberculata (2.21 %), R. quadrasi (0.21 %), T. granifera (0.11 %). Four cercarial morphotypes, namely, Parapleurolophocercous cercaria (1.80 %), Virgulate xiphidiocercaria (0.26 %), Megaluruous cercaria (0.29 %), and Echinostome cercaria (0.22 %) were recovered from the infected snail species. Prevalence of cercarial infection was significantly different (p < 0.05) among habitat types.


2007 ◽  
Vol 156 (6) ◽  
pp. 631-636 ◽  
Author(s):  
Gerasimos E Krassas ◽  
Konstantinos Tziomalos ◽  
Nikolaos Pontikides ◽  
Hadas Lewy ◽  
Zvi Laron

Objective: We aimed to test the viral hypothesis in the pathogenesis of autoimmune thyroid disease (AITD). Design: We determined the pattern of month of birth (MOB) distribution in patients with AITD and in the general population and searched for differences between them. Methods: A total of 1023 patients were included in this study; 359 patients had Graves’ hyperthyroidism (GrH) and 664 had Hashimoto’s hypothyroidism (HH). We divided the patients with HH into three subgroups according to their thyroid peroxidase (TPO) antibody titers at diagnosis: low levels (<500 IU/ml), high levels (500–1000 IU/ml), and extremely high levels (>1000 IU/ml). We used cosinor analysis to analyze the data. Results: Overall, patients with GrH and HH had a different pattern of MOB distribution when compared with the general population and between groups. Furthermore, among both patients with GrH and HH, both genders had a different pattern of MOB distribution when compared with the general population and this pattern was also different between genders. Finally, only women with extremely high titers of TPO antibodies at diagnosis and men with low or extremely high TPO antibody levels showed rhythmicity in MOB, with a pattern of MOB distribution different from that in controls. Conclusions: The different MOB seasonality in both GrH and HH points towards a similar maybe even common etiology with type 1 diabetes mellitus and multiple sclerosis, namely a seasonal viral infection as the initial trigger in the perinatal period, the clinical disease resulting from further specific damage over time.


1959 ◽  
Vol 40 (2) ◽  
pp. 221-226 ◽  
Author(s):  
W. Rowan ◽  
L. B. Keith
Keyword(s):  

1978 ◽  
Vol 56 (4) ◽  
pp. 688-694 ◽  
Author(s):  
Stephen R. Kearney ◽  
Frederick F. Gilbert

Terrestrial gastropods were collected within the 1220-ha Himsworth Game Preserve in central Ontario during 1974 to determine their abundance and habitat preference. Collections from systematically arranged plots occurred 23 May to 4 June, 6 July to 14 July, and 26 August to 5 September. In all 16 498 gastropods were collected; 4351, in the first, 5622 in the second, and 6525 in the third collection period. Sixteen species were represented with Discus cronkhitei and Zonitoides arboreus accounting for 69.3% of the specimens. Deroceras laeve and Pallifera dorsalis were the most common slugs. Gastropods (excluding slugs) showed a significant preference for mixed forest and a significant aversion to open habitat types during all collection periods. Slugs were significantly less abundant in mixed forest and more abundant in open habitat types during the third collection period.Eight of the 16 species collected (80.1% of the specimens) have previously been identified as intermediate hosts of Parelaphostrongylus tenuis. However, only 19 third-stage larvae of P. tenuis were obtained from the 16450 gastropods digested in pepsin. It is proposed that Zonitoides arboreus in association with Betula papyrifera may be important components in the transmission of P. tenuis to cervids on the Himsworth Game Preserve.


Sociobiology ◽  
2019 ◽  
Vol 66 (3) ◽  
pp. 480
Author(s):  
Angele Nicodenin Soro ◽  
Juan Lapuente ◽  
Abduoulaye Ngolo Kone ◽  
Kolo Yeo ◽  
Souleymane Konate

The goal of this study was to explain the patterns of diversity and distribution of arboreal social bees nesting in forest habitats of the Comoé National park, within the home-ranges of wild chimpanzees that consume their honey. Investigations were done using a total sixteen plots, one hectare each, established in three habitat types (mature forest island, secondary forest island and gallery forest). The diversity and distribution of arboreal social bees was estimated with visuals searches. The exploitation of the beehives of these bee by the chimpanzees was also evaluated using chimpanzees’ honey dipping tools as indicators. Results revealed five bees’ species belonging to two tribes; Meliponini (Meliponula ferruginea, Meliponula togoensis, Meliponula bocandei, Hypotrigona gribodoi) and Apini (Apis mellifera). Frequent exploitation of the honey of stingless bees by the chimpanzees was observed, except for H. gribodoi. Meliponula ferruginea was the most exploited species by chimpanzees. A total of 114 beehives were found in the overall established plots leading to an estimated density of 2.4 beehives/ha in the study area. Among the surveyed habitats, mature forest island was found to harbor the highest beehive density (4.2 beehives/ha), followed respectively by secondary-forest island (1.9 beehives/ha) and gallery forest (1.1 beehives/ha). Finally, all bee species were found nesting in cavities of trees with a DBH ranging from 15 to 87.3 cm, with a special preference for Dialium guinneense. However, the DBH of nesting trees and beehives’ height, measured from the ground level, did not significantly influence the honey exploitation by chimpanzees. In sum bee species diversity and distribution might be important in the survival of chimpanzees of a forest savanna landscape.


2020 ◽  
Author(s):  
Ketema Deribew ◽  
Etana Jaleta ◽  
Belayhun Mandefro ◽  
Zeleke Mekonnen ◽  
Delenasaw Yewhalaw ◽  
...  

Abstract Background: Land use and land cover change significantly affects biodiversity, abundance and distribution of intermediate snail host fauna. In Omo-Gibe river basin the extent of land-use change is high due to anthropogenic activities leading to habitat change of freshwater snail intermediate hosts. Most intermediate snail hosts of human Schistosome parasites belong to two genera, Biomphalaria and Bulinus. In Addition, Lymnea spp. is another important host of Fasciola which causes fasciolasis in domestic animals and human. This study aims to assess the effects of land-use on the distribution and abundance of freshwater snail intermediate hosts and cercariae infection rates of fresh water intermediate snail hosts in Omo-Gibe River basin, Ethiopia.Methods: This study was conducted in Omo-Gibe river basin in 130 sampling sites which include rivers, lakes, dams, stream, wetlands and irrigation ditches. At each site data on land use, anthropogenic activities, freshwater snail abundance and species diversity, and water samples were collected. Snails were collected from each sampling sites using a scoop (20cm x 30cm) with a mesh size of 300µm. Snails were sorted by genus on Enamel pan using forceps and preserved in labeled vials containing 75% ethanol. Live snails collected from the same habitat were sorted carefully and put in clean plastic buckets half filled with water. Afterwards, snails were provided with fresh lettuce leaves and maintained in the laboratory. Snails were then identified morphologically to family, genus and to species level. Each snail was examined for cercaria shedding by placing in a petri dish containing water and exposed to the sun for 2 hours. Cercariae were morphologically identified by microscopy. ArcGIS software of version 10.3.1 was used to map snail distribution and data were analysed using SPSS version-20.Results: The results obtained in this study shows clearly that land use change affect the distribution and abundance of fresh water snails in Omo-Gibe river basin. Fresh water snails were more abundant in farmland and settlement areas. Of the total 2,559 freshwater snails collected from 130 surveyed sites in Omo-Gibe river basin, 1749 (68.34%) belongs to medically important snail species. Biomphalaria spp.914 (35.7%),, Lymnea spp.439 (17.1%),, Physa spp. 343(13.4%) and Bulinus spp 53 (2%)). Sphaeriidae group accounted for 810 (31.6%) of the collected specimens. Biomphalaria pfeifferi was the predominant species of the total snail sampled from lakes, wetlands, rivers and irrigation ditches. Biomphalaria pfeifferi was the most infected snail species by different cercariae. Bulinus globosus and L.natalensis were infected by more than one and same type of cercariae. However, none of B. sudanica and P. acuta specimens was infected by trematode.Conclusions: The results of this study revealed that land use change altered the abundance, distribution and diversity of medically important fresh water snails in the study area. In general medically important freshwater snails which include: Biomphalaria spp, Bulinus spp and Lymnaea spp were collected from lakes, rivers, wetlands, irrigation ditches.. The medically important snail species found infected by cercaria are L. natalensis, B. pfeifferi and B. globosus. Biomphalaria pfefferi was the predominant species and highly infected by cercariae. Higher infection rate was observed in snails collected in Farmland (16.59%) and Grassland (36.6%).


1994 ◽  
Vol 68 (3) ◽  
pp. 207-210 ◽  
Author(s):  
M.Y. Manga-González ◽  
M.P. Morrondo-Pelayo

AbstractDevelopment of Neostrongylus linearis larvae was studied in the snail intermediate hosts Oestophora (Oestophora) barbula, Oestophorella buvinieri, Cepaea nemoralis and Helix (Cryptomphalus) aspersa. The molluscs of each species, all adults, were divided into groups of 40 for infection purposes. The infection doses for the first two snail species were 90 and 50 first stage larvae (L1) of N. linearis, respectively. For C. nemoralis two batches were tested: one with 200 L1 kept at 19°C and the other with 250 L1 at a temperature of 21°C. The same was done with Helix (C.) aspersa with 200 L1 at a temperature of 21°C, on the one hand and 300 L1 at 24°C on the other. One or two molluscs of each species were killed in series from the 6th day post-infection (p.i.) until the 44th. Percentage values for total larvae (1, 2 and 3) and L3 were higher with the lower dose for C. nemoralis, whilst the same was true with the higher dose in Helix (C.) aspersa. In both cases, the higher temperature appeared to contribute to cycle acceleration. Using one way analysis of variance, statistically significant differences were detected between the species of molluscs tested concerning percentages of L1 which penetrated, total larvae and L3. According to our results, the decreasing order of susceptibility of these species of molluscs as experimental intermediate hosts of N. linearis is: O. buvinieri, Oestophora (O.) barbula, C. nemoralis and Helix (C.) aspersa. It is the first time that Oestophora (O.) barbula and Oestophorella buvinieri have been named as experimental intermediate hosts of N. linearis.


Palaios ◽  
2016 ◽  
Vol 31 (6) ◽  
pp. 319-326 ◽  
Author(s):  
CLAUDIA C. JOHNSON ◽  
JACKSON K. NJAU ◽  
DIRK VAN DAMME ◽  
KATHY SCHICK ◽  
NICHOLAS TOTH

Abstract The rich record of vertebrate, hominin and archaeological remains recovered from Olduvai Gorge in northern Tanzania stands in stark contrast to the largely unexplored macroinvertebrate record from the region. Here we examine fossil malacofauna from Olduvai Gorge, inclusive of new discoveries and previous reports, and survey their potential as paleoecologic indicators. Recorded for the first time from Olduvai, an assemblage of fossil bivalve shells is attributed by character comparison to modern Chambardia wahlbergi, a freshwater unionid species widespread across Africa. The fossilized shells were localized in Bed III conglomerate channel deposits, with channel geometry exhibiting scour bases and superimposed fill structures with fining upward sequences. The ecology of recent C. wahlbergi combined with sedimentological data indicate the aquatic environment in this region during Olduvai Bed III times can be reconstructed as a periodically desiccated floodplain bordering a river channel or channels with permanent running water and marked seasonal fluctuations. This paleo-environmental setting presents drastic change compared with that of the lower Bed I and Bed II deposits, when an alkaline/saline lake extended over the site and fresh water was restricted to standing groundwater-fed pools with snail species known today to be intermediate hosts for the trematode genera Schistosoma (schistosomiasis) and Fasciola (fascioliasis). This research enhances details of landscape evolution at Olduvai basin and furthers paleoenvironmental interpretations during the time of Bed III deposition.


2019 ◽  
Vol 126 (3) ◽  
pp. 392-403 ◽  
Author(s):  
Sarin Tiatragul ◽  
Joshua M Hall ◽  
Nathaniel G Pavlik ◽  
Daniel A Warner

AbstractNesting success is critical for oviparous species to maintain viable populations. Many species often do not provide parental care (e.g. oviparous reptiles), so embryos are left to develop in the prevailing conditions of the nest. For species that occupy diverse habitats, embryos must be able to complete development across a broad range of environmental conditions. Although much research has investigated how environmental conditions influence embryo development, we know little about how nest conditions differ between diverse habitats. Anolis lizards are commonly found in various habitats including those heavily modified by humans (e.g. cities). We describe nest sites of anoles in two different habitat types: a suburban area and a nearby forest. The suburban area had less total nesting habitat but a greater variety of microenvironment conditions for females to use for nesting, compared to the forest. Suburban nests were warmer and drier with greater thermal variance compared to forest nests. Finally, we use data from the literature to predict how nest conditions may influence development. Our study provides the first quantitative assessment of anole nest sites in human-modified environments and shows how suburban habitats may generate variation in developmental rate.


2014 ◽  
Vol 51 (4) ◽  
pp. 309-317 ◽  
Author(s):  
O. Zhigileva ◽  
V. Ozhireľev ◽  
T. Stepanova ◽  
T. Moiseenko

AbstractGenetic variability of West Siberian populations of Opisthorchis felineus and two species of cyprinid fish, its second intermediate hosts, was studied by isozyme analysis. Low levels of allozyme variation and genetic differentiation in O. felineus from the Ob-Irtysh focus of opisthorchiasis were detected. The proportion of polymorphic loci was 21.1 %, the average observed heterozygosity (Hobs) was 0.008, and expected heterozygosity (Hexp) was 0.052. For most loci in O. felineus deficit of heterozygotes (FIS = 0.7424) was observed. A comparison of population genetic structure of fish and parasites showed they were not congruent. Estimates of genetic differentiation of the parasite were smaller than for the fish — its intermediate host. Migration and population structure of the second intermediate hosts do not play an important role in formation of the population-genetic structure of O. felineus in the Ob-Irtysh focus of opisthorchiasis.


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