Prior residency does not always pay off – co-infections inDaphnia

Parasitology ◽  
2010 ◽  
Vol 137 (10) ◽  
pp. 1493-1500 ◽  
Author(s):  
JENNIFER N. LOHR ◽  
MINGBO YIN ◽  
JUSTYNA WOLINSKA
Keyword(s):  
Parasite Species ◽  
Mixed Effects ◽  
Spore Production ◽  
Daphnia Galeata ◽  
Intestinal Protozoan ◽  
Ecological Processes ◽  
Single Genotype ◽  
Host Life ◽  
Multiple Species ◽  
Prior Residency

SUMMARYThe epidemiological and ecological processes which govern the success of multiple-species co-infections are as yet unresolved. Here we investigated prior versus late residency within hosts, meaning which parasite contacts the host first, to determine if the outcomes of intra-host competition are altered. We infected a single genotype of the waterfleaDaphnia galeatawith both the intestinal protozoanCaullerya mesniliand the haemolymph fungusMetschnikowiasp. (single genotype of each parasite species), as single infections, simultaneous co-infections and as sequential co-infections, with each parasite given 4 days prior residency. Simultaneous co-infections were significantly more virulent than both single infections and sequential co-infections, as measured by a decreased host life span and fecundity. Further, in addition to theDaphniahost, the parasites also suffered fitness decreases in simultaneous co-infections, as measured by spore production. The sequential co-infections, however, had mixed effects:C. mesnilibenefited from prior residency, whereasMetschnikowiasp. experienced a decline in fitness. Our results show that multiple-species co-infections ofDaphniamay be more virulent than single infections, and that prior residency does not always provide a competitive advantage.

scholarly journals Interspecific competition in honeybee intracellular gut parasites is asymmetric and favours the spread of an emerging infectious disease

2015 ◽  
Vol 282 (1798) ◽  
pp. 20141896 ◽  
Author(s):  
Myrsini E. Natsopoulou ◽  
Dino P. McMahon ◽  
Vincent Doublet ◽  
John Bryden ◽  
Robert J. Paxton
Keyword(s):  
Parasite Species ◽  
Important Determinant ◽  
Natural Populations ◽  
Parasite Prevalence ◽  
Disease Prevalence ◽  
Mixed Infections ◽  
Asymmetric Competition ◽  
Nosema Apis ◽  
Priority Effect ◽  
Ecological Processes

There is increasing appreciation that hosts in natural populations are subject to infection by multiple parasite species. Yet the epidemiological and ecological processes determining the outcome of mixed infections are poorly understood. Here, we use two intracellular gut parasites (Microsporidia), one exotic and one co-evolved in the western honeybee ( Apis mellifera ), in an experiment in which either one or both parasites were administered either simultaneously or sequentially. We provide clear evidence of within-host competition; order of infection was an important determinant of the competitive outcome between parasites, with the first parasite significantly inhibiting the growth of the second, regardless of species. However, the strength of this ‘priority effect’ was highly asymmetric, with the exotic Nosema ceranae exhibiting stronger inhibition of Nosema apis than vice versa. Our results reveal an unusual asymmetry in parasite competition that is dependent on order of infection. When incorporated into a mathematical model of disease prevalence, we find asymmetric competition to be an important predictor of the patterns of parasite prevalence found in nature. Our findings demonstrate the wider significance of complex multi-host–multi-parasite interactions as drivers of host–pathogen community structure.

Parasitism of asymmetrical pelvic phenotypes in stickleback

1997 ◽  
Vol 75 (12) ◽  
pp. 2084-2094 ◽  
Author(s):  
T. E. Reimchen
Keyword(s):  
Genetic Background ◽  
Gasterosteus Aculeatus ◽  
Parasite Species ◽  
Juvenile Fish ◽  
Bilateral Symmetry ◽  
Early Ontogeny ◽  
Directional Asymmetry ◽  
Lower Infection ◽  
Resistance To Infection ◽  
Multiple Species

Subtle departures from bilateral symmetry in morphological traits result from environmental and genetic stresses and may signal an inferior genetic background. Because one correlate of an inferior genome is reduced resistance to infection, such asymmetry may provide a phenotypic signal of susceptibility to parasitism. I tested this hypothesis in a population of threespine stickleback (Gasterosteus aculeatus) with cestode and nematode infections and bilateral asymmetry of the pelvis. Seventeen percent of the fish had an asymmetrical pelvis and, of these, 78% had greater expression on the left side; this directionality suggests a genetic influence. Females had consistently greater left-side asymmetry than did males. The incidence of total infection (all parasite species) in the largest adult fish (> 60 mm body length) was greater in asymmetrical phenotypes, and this occurred in both sexes and for each parasite species (Schistocephalus solidus, Cyathocephalus truncatus, Eustrongylides spp.), even when multiple-species infections were excluded. Contrary to prediction, however, in juvenile fish (< 20 mm) and yearlings (20–40 mm) but not subadults and adults (40–60 mm), asymmetrical phenotypes had significantly lower infection rates than symmetrical fish. This pattern occurred in both sexes, but the extent of the association varied over the 14 years of sampling. Consequently, if the directional asymmetry of the pelvis is under genetic control, asymmetry would be favoured during early ontogeny but selected against during the adult stages. The data support the hypothesis that asymmetry is a phenotypic signal of parasitism, but the unexpected bidirectionality of the association within a single population suggests increased complexity of the processes coupling asymmetry and genetic background.

Timing and order of exposure to two echinostome species affect patterns of infection in larval amphibians

Parasitology ◽  
2020 ◽  
Vol 147 (13) ◽  
pp. 1515-1523
Author(s):  
Logan S. Billet ◽  
Vanessa P. Wuerthner ◽  
Jessica Hua ◽  
Rick A. Relyea ◽  
Jason T. Hoverman
Keyword(s):  
Rana Pipiens ◽  
Parasite Species ◽  
Priority Effects ◽  
Ecological Studies ◽  
Field Surveys ◽  
Larval Amphibians ◽  
Lower Infection ◽  
Multiple Species ◽  
Echinostoma Trivolvis ◽  
Timing Of Exposure

AbstractThe study of priority effects with respect to coinfections is still in its infancy. Moreover, existing coinfection studies typically focus on infection outcomes associated with exposure to distinct sets of parasite species, despite that functionally and morphologically similar parasite species commonly coexist in nature. Therefore, it is important to understand how interactions between similar parasites influence infection outcomes. Surveys at seven ponds in northwest Pennsylvania found that multiple species of echinostomes commonly co-occur. Using a larval anuran host (Rana pipiens) and the two most commonly identified echinostome species from our field surveys (Echinostoma trivolvis and Echinoparyphium lineage 3), we examined how species composition and timing of exposure affect patterns of infection. When tadpoles were exposed to both parasites simultaneously, infection loads were higher than when exposed to Echinoparyphium alone but similar to being exposed to Echinostoma alone. When tadpoles were sequentially exposed to the parasite species, tadpoles first exposed to Echinoparyphium had 23% lower infection loads than tadpoles first exposed to Echinostoma. These findings demonstrate that exposure timing and order, even with similar parasites, can influence coinfection outcomes, and emphasize the importance of using molecular methods to identify parasites for ecological studies.

scholarly journals Prevalence of simian malaria parasites in macaques of Singapore

2021 ◽  
Vol 15 (1) ◽  
pp. e0009110
Author(s):  
Meizhi Irene Li ◽  
Diyar Mailepessov ◽  
Indra Vythilingam ◽  
Vernon Lee ◽  
Patrick Lam ◽  
...  
Keyword(s):  
Human Population ◽  
Malaria Parasite ◽  
Parasite Species ◽  
Plasmodium Knowlesi ◽  
Malaria Parasites ◽  
Simian Malaria ◽  
Specific Pcr ◽  
Natural Hosts ◽  
Multiple Species ◽  
Species Specific

Plasmodium knowlesi is a simian malaria parasite currently recognized as the fifth causative agent of human malaria. Recently, naturally acquired P. cynomolgi infection in humans was also detected in Southeast Asia. The main reservoir of both parasites is the long-tailed and pig-tailed macaques, which are indigenous in this region. Due to increased urbanization and changes in land use, there has been greater proximity and interaction between the long-tailed macaques and the general population in Singapore. As such, this study aims to determine the prevalence of simian malaria parasites in local macaques to assess the risk of zoonosis to the general human population. Screening for the presence of malaria parasites was conducted on blood samples from 660 peridomestic macaques collected between Jan 2008 and Mar 2017, and 379 wild macaques collected between Mar 2009 and Mar 2017, using a Pan-Plasmodium-genus specific PCR. Positive samples were then screened using a simian Plasmodium species-specific nested PCR assay to identify the species of parasites (P. knowlesi, P. coatneyi, P. fieldi, P. cynomolgi, and P. inui) present. All the peridomestic macaques sampled were tested negative for malaria, while 80.5% of the 379 wild macaques were infected. All five simian Plasmodium species were detected; P. cynomolgi being the most prevalent (71.5%), followed by P. knowlesi (47.5%), P. inui (42.0%), P. fieldi (32.5%), and P. coatneyi (28.5%). Co-infection with multiple species of Plasmodium parasites was also observed. The study revealed that Singapore’s wild long-tailed macaques are natural hosts of the five simian malaria parasite species, while no malaria was detected in all peridomestic macaques tested. Therefore, the risk of simian malaria transmission to the general human population is concluded to be low. However, this can be better demonstrated with the incrimination of the vectors of simian malaria parasites in Singapore.

scholarly journals Antagonism between parasites within snail hosts impacts the transmission of human schistosomiasis

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Martina R Laidemitt ◽  
Larissa C Anderson ◽  
Helen J Wearing ◽  
Martin W Mutuku ◽  
Gerald M Mkoji ◽  
...  
Keyword(s):  
Parasite Species ◽  
Life Cycles ◽  
Complex Environments ◽  
Biomphalaria Pfeifferi ◽  
Human Parasite ◽  
Host Life ◽  
The Impact ◽  
Further Development ◽  
Antagonistic Interactions ◽  
Trematode Parasites

Human disease agents exist within complex environments that have underappreciated effects on transmission, especially for parasites with multi-host life cycles. We examined the impact of multiple host and parasite species on transmission of the human parasite Schistosoma mansoni in Kenya. We show S. mansoni is impacted by cattle and wild vertebrates because of their role in supporting trematode parasites, the larvae of which have antagonistic interactions with S. mansoni in their shared Biomphalaria vector snails. We discovered the abundant cattle trematode, Calicophoron sukari, fails to develop in Biomphalaria pfeifferi unless S. mansoni larvae are present in the same snail. Further development of S. mansoni is subsequently prevented by C. sukari’s presence. Modeling indicated that removal of C. sukari would increase S. mansoni-infected snails by two-fold. Predictable exploitation of aquatic habitats by humans and their cattle enable C. sukari to exploit S. mansoni, thereby limiting transmission of this human pathogen.

Ectoparasites and endoparasites of fish form networks with different structures

Parasitology ◽  
2015 ◽  
Vol 142 (7) ◽  
pp. 901-909 ◽  
Author(s):  
S. BELLAY ◽  
E. F. DE OLIVEIRA ◽  
M. ALMEIDA-NETO ◽  
M. A. R. MELLO ◽  
R. M. TAKEMOTO ◽  
...  
Keyword(s):  
Species Composition ◽  
Host Species ◽  
Parasite Species ◽  
Parasite Fauna ◽  
Interaction Patterns ◽  
Host Fish ◽  
Ecological Processes ◽  
Fauna Composition ◽  
The Relationship ◽  
Interaction Intensity

SUMMARYHosts and parasites interact with each other in a variety of ways, and this diversity of interactions is reflected in the networks they form. To test for differences in interaction patterns of ecto- and endoparasites we analysed subnetworks formed by each kind of parasites and their host fish species in fish–parasite networks for 22 localities. We assessed the proportion of parasite species per host species, the relationship between parasite fauna composition and host taxonomy, connectance, nestedness and modularity of each subnetwork (n = 44). Furthermore, we evaluated the similarity in host species composition among modules in ecto- and endoparasite subnetworks. We found several differences between subnetworks of fish ecto- and endoparasites. The association with a higher number of host species observed among endoparasites resulted in higher connectance and nestedness, and lower values of modularity in their subnetworks than in those of ectoparasites. Taxonomically related host species tended to share ecto- or endoparasites with the same interaction intensity, but the species composition of hosts tended to differ between modules formed by ecto- and endoparasites. Our results suggest that different evolutionary and ecological processes are responsible for organizing the networks formed by ecto- and endoparasites and fish.

Alternative life-history and transmission strategies in a parasite: first come, first served?

Parasitology ◽  
2005 ◽  
Vol 132 (1) ◽  
pp. 135-141 ◽  
Author(s):  
R. POULIN ◽  
F. LEFEBVRE
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Intermediate Host ◽  
Host Location ◽  
Parasite Species ◽  
Fish Host ◽  
Transmission Strategy ◽  
External Cues ◽  
Host Life ◽  
Host Tissues

Alternative transmission strategies are common in many parasitic organisms, often representing discrete phenotypes adopted in response to external cues. The facultative truncation of the normal 3-host life-cycle to a 2-host cycle in many trematodes provides an example: some individuals mature precociously, via progenesis, in their intermediate host and produce eggs without the need to reach a definitive host. The factors that determine how many and which individuals adopt the truncated life-cycle within a parasite population remain unknown. We investigated the occurrence of progenesis in the trematode Stegodexamene anguillae within its fish intermediate host. Location within the host was a key determinant of progenesis. Although the size and egg output of progenetic metacercariae encysted in host gonads did not differ from those of the few progenetic metacercariae in other host tissues, the likelihood of metacercariae becoming progenetic was much higher for those in the gonads than those elsewhere in the host. Progenetic parasites can only evacuate their eggs along with host eggs or sperm, providing a link between the parasite's transmission strategy and its location in the host. Host size and sex, and the presence of other parasite species in the host, did not affect the occurrence of progenesis in S. anguillae. However, the proportion of metacercariae in host gonads and the proportion of progenetic metacercariae both decreased with increasing numbers of S. anguillae per host. These results suggest that progenesis is adopted mostly by the parasites that successfully establish in host gonads. These are generally the first to infect a fish; subsequent arrivals settle in other tissues as the gonads quickly become saturated with parasites. In this system, the site of encystment within the fish host both promotes and constrains the adoption of a facultative, truncated life-cycle by the parasite.

scholarly journals Longitudinal analysis of pinnipeds in the northwest Atlantic provides insights on endemic circulation of phocine distemper virus

2021 ◽  
Vol 288 (1962) ◽  
Author(s):  
Wendy Puryear ◽  
Kaitlin Sawatzki ◽  
Andrea Bogomolni ◽  
Nichola Hill ◽  
Alexa Foss ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Western Europe ◽  
Clinical Signs ◽  
Ecological Processes ◽  
Northwest Atlantic ◽  
Viral Ecology ◽  
The North ◽  
Phocine Distemper Virus ◽  
Waning Immunity ◽  
Multiple Species

Phocine distemper virus (PDV) is a morbillivirus that circulates within pinnipeds in the North Atlantic. PDV has caused two known unusual mortality events (UMEs) in western Europe (1988, 2002), and two UMEs in the northwest Atlantic (2006, 2018). Infrequent cross-species transmission and waning immunity are believed to contribute to periodic outbreaks with high mortality in western Europe. The viral ecology of PDV in the northwest Atlantic is less well defined and outbreaks have exhibited lower mortality than those in western Europe. This study sought to understand the molecular and ecological processes underlying PDV infection in eastern North America. We provide phylogenetic evidence that PDV was introduced into northwest Atlantic pinnipeds by a single lineage and is now endemic in local populations. Serological and viral screening of pinniped surveillance samples from 2006 onward suggest there is continued circulation of PDV outside of UMEs among multiple species with and without clinical signs. We report six full genome sequences and nine partial sequences derived from harbour and grey seals in the northwest Atlantic from 2011 through 2018, including a possible regional variant. Work presented here provides a framework towards greater understanding of how recovering populations and shifting species may impact disease transmission.

Echinococcus multilocularis and Echinococcus canadensis in wolves from western Canada

Parasitology ◽  
2013 ◽  
Vol 141 (2) ◽  
pp. 159-163 ◽  
Author(s):  
JANNA M. SCHURER ◽  
KAREN M. GESY ◽  
BRETT T. ELKIN ◽  
EMILY J. JENKINS
Keyword(s):  
North America ◽  
Echinococcus Multilocularis ◽  
Wildlife Conservation ◽  
Parasite Species ◽  
Mixed Infections ◽  
Western Canada ◽  
Echinococcus Canadensis ◽  
Sampling Locations ◽  
Multiple Species ◽  
Canadian Wildlife

SUMMARYEchinococcus species are important parasites of wildlife, domestic animals and people worldwide; however, little is known about the prevalence, intensity and genetic diversity of Echinococcus tapeworms in Canadian wildlife. Echinococcus tapeworms were harvested from the intestines of 42% of 93 wolves (Canis lupus) from five sampling regions in the Northwest Territories, Manitoba and Saskatchewan, and visually identified to genus level by microscopic examination. Genetic characterization was successful for tapeworms from 30 wolves, and identified both Echinococcus canadensis and Echinococcus multilocularis in all sampling locations. Mixed infections of E. canadensis/E. multilocularis, as well as the G8/G10 genotypes of E. canadensis were observed. These findings suggest that wolves may be an important definitive host for both parasite species in western Canada. This represents the first report of wolves naturally infected with E. multilocularis in North America, and of wolves harbouring mixed infections with multiple species and genotypes of Echinococcus. These observations provide important information regarding the distribution and diversity of zoonotic species of Echinococcus in western North America, and may be of interest from public health and wildlife conservation perspectives.

Modeling Intraindividual Variability in Three-Level Multilevel Models

Methodology ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 95-108 ◽  
Author(s):  
Steffen Nestler ◽  
Katharina Geukes ◽  
Mitja D. Back
Keyword(s):  
Multilevel Model ◽  
Multilevel Models ◽  
Mixed Effects ◽  
Repeated Measurements ◽  
Scale Model ◽  
Suggested Approach ◽  
Psychological Study ◽  
Level Data ◽  
Ecological Momentary ◽  
Momentary Assessment

Abstract. The mixed-effects location scale model is an extension of a multilevel model for longitudinal data. It allows covariates to affect both the within-subject variance and the between-subject variance (i.e., the intercept variance) beyond their influence on the means. Typically, the model is applied to two-level data (e.g., the repeated measurements of persons), although researchers are often faced with three-level data (e.g., the repeated measurements of persons within specific situations). Here, we describe an extension of the two-level mixed-effects location scale model to such three-level data. Furthermore, we show how the suggested model can be estimated with Bayesian software, and we present the results of a small simulation study that was conducted to investigate the statistical properties of the suggested approach. Finally, we illustrate the approach by presenting an example from a psychological study that employed ecological momentary assessment.

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