Single-clone and mixed-clone infections versus host environment in Crithidia bombi infecting bumblebees

Parasitology ◽  
1998 ◽  
Vol 117 (4) ◽  
pp. 331-336 ◽  
Author(s):  
B. IMHOOF ◽  
P. SCHMID-HEMPEL
Keyword(s):  
Bombus Terrestris ◽  
Infection Intensity ◽  
Parasite Prevalence ◽  
Mixed Genotype ◽  
Host Environment ◽  
Crithidia Bombi ◽  
The Family ◽  
Single Clone ◽  
Parasite Evolution ◽  
Host Heterogeneity

Current theories assume that adaptive parasite evolution explains variation in the level of virulence and parasite success. In particular, mixed-genotype infections by parasites should generally be more virulent, and faster multiplying strains more successful, either because fixed strategies have evolved or because parasites facultatively alter virulence in response to co-infecting competitors. We compared several measures of parasite success and virulence between single-clone and mixed-clone infections of 2 strains of the trypanosome Crithidia bombi in its bumblebee host, Bombus terrestris. Contrary to expectation, we could not find differences between single-clone and mixed-clone infections in parasite prevalence, infection success, duration and clearance rate. However, a clearly significant effect of colony on infection intensity was present, and the colony effect emerged in virtually all other measures. We thus conclude that host environment as defined by the family (colony) genotype and thus host heterogeneity are more important in determining parasite virulence than the parasite characteristics. This does not invalidate modern theories of parasite evolution but suggests that variation in both hosts and parasites must be taken into account in more detail.

scholarly journals Host heterogeneity mitigates virulence evolution

2020 ◽  
Vol 16 (1) ◽  
pp. 20190744 ◽  
Author(s):  
P. Signe White ◽  
Angela Choi ◽  
Rishika Pandey ◽  
Arthur Menezes ◽  
McKenna Penley ◽  
...  
Keyword(s):  
Experimental Evolution ◽  
Parasite Prevalence ◽  
Mixed Genotype ◽  
Selective Pressures ◽  
Virulence Evolution ◽  
Specific Host ◽  
Trade Offs ◽  
Evolutionary Trajectories ◽  
Parasite Populations ◽  
Host Heterogeneity

Parasites often infect genetically diverse host populations, and the evolutionary trajectories of parasite populations may be shaped by levels of host heterogeneity. Mixed genotype host populations, compared to homogeneous host populations, can reduce parasite prevalence and potentially reduce rates of parasite adaptation due to trade-offs associated with adapting to specific host genotypes. Here, we used experimental evolution to select for increased virulence in populations of the bacterial parasite Serratia marcescens exposed to either heterogeneous or homogeneous populations of Caenorhabditis elegans . We found that parasites exposed to heterogeneous host populations evolved significantly less virulence than parasites exposed to homogeneous host populations over several hundred bacterial generations. Thus, host heterogeneity impeded parasite adaptation to host populations. While we detected trade-offs in virulence evolution, parasite adaptation to two specific host genotypes also resulted in modestly increased virulence against the reciprocal host genotypes. These results suggest that parasite adaptation to heterogeneous host populations may be impeded by both trade-offs and a reduction in the efficacy of selection as different host genotypes exert different selective pressures on a parasite population.

scholarly journals Parasite prevalence, infection intensity and richness in an endangered population, the Atlantic-Gaspésie caribou

2018 ◽  
Vol 7 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Geneviève Turgeon ◽  
Susan J. Kutz ◽  
Manigandan Lejeune ◽  
Martin-Hugues St-Laurent ◽  
Fanie Pelletier
Keyword(s):  
Infection Intensity ◽  
Parasite Prevalence ◽  
Endangered Population

Helminth Parasites of Anurans from Zaria, Northern Guinea Savannah Zone of Nigeria

2020 ◽  
Vol 41 (2) ◽  
Author(s):  
E.U Anele ◽  
I.H Nock ◽  
I.M.K Gadzama
Keyword(s):  
Small Intestine ◽  
Infection Intensity ◽  
Parasite Prevalence ◽  
Xenopus Tropicalis ◽  
Helminth Parasites ◽  
Infestation Level ◽  
New Host ◽  
The Difference ◽  
Savannah Zone ◽  
New Host Records

Helminth parasitc infections were investigated in 150 Anurans collected in parts of the Northern Guinea Savannah during thedry and wet seasons of 2016. The Anurans that were investigated included Amietophrynus regularis, Kassina senegalensis,Afrixalus vittiger, Xenopus tropicalis, Xenopus fischbergi, Pyxiecephalus cf. edulis, Hoplobatrachus occipitalis, Amniranagalamensis and Ptychadena pumilio. Overall prevalence of helminth parasites was 64% (94/150). Seven species ofhelminths belonging to three taxonomic classes were recovered: Monogenea 4%, Trematoda 19.33% and Nematoda 40.67%were identified. Eupolystoma alluaudi (30%) was the only monogenean recorded from the bladder of S. regularis. Tematodesfound were Diplodischus fishthalicus (53.49%) and Haematoloechus micrurus (67.45%) from the rectum and lungs of H.occipitalis, respectively. Nematodes included Camallanus microcephalus from the oesophagus and small intestine of X.fischbergi ( 62.96%) and X. tropicalis (100 %), respectively, Camallanus dimitrovi (25.58%) from the small intestine andrectum of H. occipitalis, an unidentified nematode from the oesophagus and small intestine of X. fischbergi (1.85%) and X.tropicalis (33.33%), and an Aplectana (85.00%%) species from the small intestine and rectum of S. regularis. Except forEupolystoma alluaudi, the infestation level was generally low. Parasite prevalence was higher during the wet (39.33%) thandry (24.67%) season and the difference was not significant (p = 0.17). The prevalence and infection intensity were lower thanthose reported from anurans in southern biotopes of Nigeria. The occurrence of Camallanus macrocephalus is a new recordfor Nigeria, while X. fischbergi and X. tropicalis are new host records for C. macrocephalus. Keywords: Anurans, helminth, prevalence, Northern Guinea Savannah, Nigeria

Infection with the trypanosome Crithidia bombi and expression of immune-related genes in the bumblebee Bombus terrestris

2010 ◽  
Vol 34 (7) ◽  
pp. 705-709 ◽  
Author(s):  
Helge Schlüns ◽  
Ben M. Sadd ◽  
Paul Schmid-Hempel ◽  
Ross H. Crozier
Keyword(s):  
Bombus Terrestris ◽  
Crithidia Bombi ◽  
Immune Related Genes

scholarly journals A Novel Parasitic, Syndinean Dinoflagellate Euduboscquella triangula Infecting the Tintinnid Helicostomella longa

2021 ◽  
Vol 8 ◽  
Author(s):  
Jung Min Choi ◽  
Jae Ho Jung ◽  
Ki Hong Kim ◽  
D. Wayne Coats ◽  
Young Ok Kim
Keyword(s):  
Infection Intensity ◽  
Parasite Prevalence ◽  
Molecular Data ◽  
Live Cells ◽  
Representative Sequence ◽  
Rdna Sequences ◽  
Group I ◽  
Morphological And Molecular Data ◽  
Type 3 ◽  
Developmental Features

A tintinnid species, Helicostomella longa, infected by the parasitic dinoflagellate Euduboscquella triangula n. sp. was discovered from the southern coast of Korea in August of 2015 and 2016. Parasite morphology and development were analyzed by observation of live cells and protargol-stained specimens. The parasite was determined to be a new species in the genus Euduboscquella based on morphological and molecular data. A representative sequence of the novel species clustered in Euduboscquella group I. The morphological and developmental features of E. triangula were distinguished from those of its congeners by: (1) numerous shallow and intertwining grooves on an inconspicuous shield; (2) sporocytes initially forming a short chain, but separating after the second or third division regardless of spore type; (3) production of motile mushroom-shaped dinospores, non-motile spherical spores, and non-motile triangular spores. Dinospores were formed by ca. 28% of infections, while both non-motile spherical and triangular spores occurred at a frequency of ca. 36%. All spore types showed completely identical 18S rDNA sequences. Parasite prevalence was 15.5 and 8.3% on 17 and 24 August of 2015, respectively, with infection intensity on both dates being 1.3.

Parasitofauna of ground-dwelling anurans from cocoa plantations in Ugboke, Edo State, Nigeria

2021 ◽  
Vol 18 (1) ◽  
pp. 8-18
Author(s):  
O. Edo-Taiwo ◽  
M.S.O. Aisien
Keyword(s):  
Parasite Species ◽  
Infection Intensity ◽  
Parasite Burden ◽  
Parasite Prevalence ◽  
Nematode Species ◽  
Helminth Parasites ◽  
Susceptible Host ◽  
Edo State ◽  
The Village ◽  
Cocoa Plantation

The parasitofauna of ground-dwelling anurans from pesticide-treated cocoa plantations (CP) in Ojo Camp, Ugboke, Edo State of Nigeria were investigated and compared with those recovered from host specimens collected from the village settlement (VS). The anurans were caught by hand following visual or acoustic location. The anurans encountered in both the VS and the CP included Aubria subsigillata, Hylarana spp. (H. albolabris and H. galamensis), Sclerophrys spp. (S. maculata and S. regularis), Ptychadena spp. (P. aequiplicata, P. longirostris, P. mascareniensis, P. oxyrhynchus and P. pumilio) and Hoplobatrachus occipitalis. Hylarana galamensis, Ptychadena spp. and Sclerophrys spp. were encountered in the VS and the CP while Aubria subsigillata, H. albolabris and H. occipitalis occurred only in the CP. The helminth parasites recovered included four cestode species (adult of Cylindrotaenia jaegerskioeldi and three encysted  proteocephalid larvae), five Polystoma spp. 11 species of digeneans and 19 nematode species. More parasite species were recovered from toads collected from the VS; parasite prevalence was generally low in both habitats but the intensity of infection was higher in the specimens collected from the VS. Although cip A. subsigillata and H. ocitalis both occurred in the CP, A. subsigillata was the more susceptible host of the two, harbouring 16 helminth parasites as against four from H. occipitalis. Polystomes were recovered from H. albolabris and H. galamensis in addition to Diplodiscus fischthalicus and Mesocoelium spp. Infections occurred  mostly among the Ptychadeniidae collected from the CP, with prevalence ranging from 12.5% to 100% and infection intensity from 1.0 to 13.0. The generally low parasite burden in anurans from the CP can possibly be attributed to the pesticide contamination of this habitat which may have hindered the development of the free-living stages of parasites in this milieu. Keywords: Anurans; cocoa plantation; pesticides; parasitofauna; prevalence; intensity.  

Immunocompetence in workers of a social insect, Bombus terrestris L., in relation to foraging activity and parasitic infection

2000 ◽  
Vol 78 (6) ◽  
pp. 1060-1066 ◽  
Author(s):  
Claudie Doums ◽  
Paul Schmid-Hempel
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Intestinal Parasite ◽  
Bombus Terrestris ◽  
Parasitic Infection ◽  
General Mechanism ◽  
Immune Defence ◽  
Foraging Activity ◽  
Natural Conditions ◽  
Crithidia Bombi

The immune system is a general mechanism that reduces the fitness cost of parasitism. In this study, we examined variation in immune responses under natural conditions in the bumblebee Bombus terrestris. Using 14 colonies reared in the field, we compared the immune response to an artificial implant between workers that could or could not forage (86 control and 91 nonforaging workers). Foraging activity was prevented by cutting a large part of the wings. As expected, control workers had lower immune responses than nonforaging workers in 10 of 14 colonies. Overall, the treatment effect was significant even though weak, suggestive of a trade-off between immune defence and foraging activity. We also examined the environmental factors that might covary with the immune response in workers. The immune response significantly decreased in workers that were naturally infected by the intestinal parasite Crithidia bombi and increased with a measure of colony success, the maximum number of workers. These correlations suggest that the strength of immune responses reflects individual, and hence colony condition.

scholarly journals Effects of natal and novel Crithidia bombi (Trypanosomatidae) infections on Bombus terrestris hosts

2007 ◽  
Vol 55 (1) ◽  
pp. 86-90 ◽  
Author(s):  
C. P. Yourth ◽  
M. J. F. Brown ◽  
P. Schmid-Hempel
Keyword(s):  
Bombus Terrestris ◽  
Crithidia Bombi

Genetic variation in susceptibility of Atlantic salmon to the sea louse Caligus elongatus Nordmann, 1832

1999 ◽  
Vol 77 (8) ◽  
pp. 1332-1335 ◽  
Author(s):  
A Mustafa ◽  
B M MacKinnon
Keyword(s):  
Atlantic Salmon ◽  
Infection Intensity ◽  
Sea Lice ◽  
Average Intensity ◽  
Intensity Of Infection ◽  
Susceptibility To Infection ◽  
Full Sibling ◽  
Genetic Heritability ◽  
The Family ◽  
Selection For

Differences in susceptibility of distinct full-sibling families of Atlantic salmon, Salmo salar, to infection with the sea louse Caligus elongatus were investigated. Infection intensity with mobile stages of sea lice was monitored on 419 individual salmon from 73 full-sibling families held in a single sea pen and exposed to similar numbers of infectious larvae originating from nearby fish. The average intensity of infection calculated from the family groups ranged from 5 to 25, with 70 families having an average intensity of 10 or more preadult or adult sea lice. The overall average intensity was 15.30 and the prevalence was 100%. The calculated genetic heritability (h2) was 0.22, which indicates that this variability in susceptibility to infection may be heritable. This level of heritability also suggests that selection for improved resistance to sea lice is feasible.

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