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Anna E. Jolles - One of the best experts on this subject based on the ideXlab platform.
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hidden consequences of living in a wormy world nematode induced immune suppression facilitates tuberculosis invasion in african buffalo
The American Naturalist, 2010Co-Authors: Vanessa O Ezenwa, Rampal S. Etienne, Albano Bejapereira, Gordon Luikart, Anna E. JollesAbstract:Abstract: Most hosts are infected with multiple parasites, and responses of the immune system to co‐occurring parasites may influence disease spread. Helminth infection can bias the host immune response toward a T‐helper type 2 (Th2) over a type 1 (Th1) response, impairing the host’s ability to control concurrent intracellular Microparasite infections and potentially modifying disease dynamics. In humans, immune‐mediated interactions between helminths and Microparasites can alter host susceptibility to diseases such as HIV, tuberculosis (TB), and malaria. However, the extent to which similar processes operate in natural animal populations and influence disease spread remains unknown. We used cross‐sectional, experimental, and genetic studies to show that gastrointestinal nematode infection alters immunity to intracellular Microparasites in free‐ranging African buffalo (Syncerus caffer). Buffalo that were more resistant to nematode infection had weaker Th1 responses, there was significant genotypic variati...
Serge Morand - One of the best experts on this subject based on the ideXlab platform.
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The diversity of Microparasites of rodents: a comparative analysis that helps in identifying rodent-borne rich habitats in Southeast Asia
Infection Ecology & Epidemiology, 2013Co-Authors: Frédéric Bordes, Vincent Herbreteau, Stéphane Dupuy, Yannick Chaval, Annelise Tran, Serge MorandAbstract:Background: Predicting habitats prone to favor disease transmission is challenging due to confounding information on habitats, reservoirs, and diseases. Comparative analysis, which aims at investigating ecological and evolutionary patterns among species, is a tool that may help. The emergence of zoonotic pathogens is a major health concern and is closely linked to habitat modifications by human activities. Risk assessment requires a better knowledge of the interactions between hosts, parasites, and the landscape. Methods: We used information from a field spatial study that investigated the distribution of murid rodents, in various habitats of three countries in Southeast Asia, in combination with their status of infection by 10 taxa of Microparasites obtained from the literature. Microparasite species richness was calculated by rodent species on 20,272 rodents of 13 species. Regression tree models and generalized linear models were used to explain Microparasite diversity by the average distance between the trapping site and five categories of land cover: forest, steep agriculture land, flat agriculture land, water, and built-up surfaces. Another variable taken into account was the slope. Results: We found that Microparasite diversity was positively associated with flat agriculture land, in this context mainly rice fields, and negatively associated with slope. Microparasite diversity decreased sharply a 100 m or less from flat agriculture land. Conclusion: We conclude that there is high Microparasite circulation in rodents of flooded farmlands, meaning possibly a higher risk of disease for human inhabitants.
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Rodent-borne diseases in Thailand: targeting rodent carriers and risky habitats.
Infection Ecology & Epidemiology, 2012Co-Authors: Vincent Herbreteau, Frédéric Bordes, Sathaporn Jittapalapong, Yupin Supputamongkol, Serge MorandAbstract:Background: Comparative analysis, which aims at investigating ecological and evolutionary patterns among species, may help at targeting reservoirs of zoonotic diseases particularly in countries presenting high biodiversity. Here, we developed a simple method to target rodent reservoirs using published studies screening Microparasite infections. Methods: We compiled surveys of Microparasites investigated in rodents trapped in Thailand. The data comprise a total of 17,358 rodents from 18 species that have been investigated for a total of 10 Microparasites (viruses, bacteria and protozoans). We used residual variation of Microparasite richness controlled for both rodent sample size and pathogens' screening effort to identify major rodent reservoirs and potential risky habitats. Results: Microparasite species richness was positively related to rodent sample size and pathogens' screening effort. The investigation of the residual variations of Microparasite species richness showed that several rodent species harboured more pathogens than expected by the regression model. Similarly, higher pathogen richness than expected was observed in rodents living in non-flooded lands, forests and paddy fields. Conclusion: Our results suggest to target some rodent species that are not commonly investigated for pathogen screening or surveillance such as R. andamanensis or B. savilei, and that non-flooded lands and forests should be more taken into caution, whereas much surveys focused on paddy rice fields and households.
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Microparasite species richness in rodents is higher at lower latitudes and is associated with reduced litter size
Oikos, 2011Co-Authors: Frédéric Bordes, Jeanfrancois Guegan, Serge MorandAbstract:Parasite species loads are expected to be higher in the tropics and higher parasite species richness to have cumulative eff ects on host physiology or demography. Despite being regularly assumed or predicted, empirical evidence on species - latitude patterns is scarce or contradictory and studies on the impacts of concomitant infections have mainly been done at host intra-specifi c level. Broad generalizations are then very hard, if not spurious. By focusing on rodent species and their non-eukaryotic Microparasites (i.e. viruses and bacteria), we investigated, using a comparative approach, Microparasite species richness across rodent species according to the latitude where they occur. We also explored the links between rodents ' reproductive traits, latitude and Microparasite species richness. We fi nd for the fi rst time in rodents that virus species richness increases towards tropical latitudes, and that rodent litter size seems to decrease when Microparasite species richness increases independently from the latitude. Th ese results support the hypotheses that rodent species in the tropics eff ectively harbour higher parasite species loads, at least in terms of species richness for viruses, and that parasite species richness infl uences rodent life-history traits. Although some other factors, such as seasonality, were not taken into account due the lack of data, our study stresses the idea that chronic Microparasite infections may have detrimental eff ects on their rodent host reservoirs, notably by aff ecting litter size. (Resume d'auteur)
Gordon Luikart - One of the best experts on this subject based on the ideXlab platform.
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hidden consequences of living in a wormy world nematode induced immune suppression facilitates tuberculosis invasion in african buffalo
The American Naturalist, 2010Co-Authors: Vanessa O Ezenwa, Rampal S. Etienne, Albano Bejapereira, Gordon Luikart, Anna E. JollesAbstract:Abstract: Most hosts are infected with multiple parasites, and responses of the immune system to co‐occurring parasites may influence disease spread. Helminth infection can bias the host immune response toward a T‐helper type 2 (Th2) over a type 1 (Th1) response, impairing the host’s ability to control concurrent intracellular Microparasite infections and potentially modifying disease dynamics. In humans, immune‐mediated interactions between helminths and Microparasites can alter host susceptibility to diseases such as HIV, tuberculosis (TB), and malaria. However, the extent to which similar processes operate in natural animal populations and influence disease spread remains unknown. We used cross‐sectional, experimental, and genetic studies to show that gastrointestinal nematode infection alters immunity to intracellular Microparasites in free‐ranging African buffalo (Syncerus caffer). Buffalo that were more resistant to nematode infection had weaker Th1 responses, there was significant genotypic variati...
Jolles, Anna E. - One of the best experts on this subject based on the ideXlab platform.
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drivers_dispersal_African_buffalo
2020Co-Authors: Spaan, Robert S, Ezenwa, Vanessa O., Epps, Clinton W, Jolles, Anna E.Abstract:Dispersal status, animal traits, herd identity, environmental variables, gastrointestinal parasites and Microparasite infections dat
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Data from: Interactions between micro- and macroparasites predict Microparasite species richness across primates
2013Co-Authors: Nunn, Charles L., Jolles, Anna E., Brezine Carrie, Ezenwa, Vanessa O.Abstract:Most wild animals face concurrent challenges by multiple infectious organisms, and immunological responses triggered by some parasites may increase susceptibility to other infectious agents. Immune-mediated interactions among parasites have been investigated among individuals in a population, but less is known about broader comparative patterns. We investigated the "macro-micro facilitation hypothesis" that higher helminth prevalence in a host species provides greater opportunities for intracellular parasites to invade, resulting in higher richness of intracellular Microparasites. We obtained data on average helminth prevalence for 70 primate hosts, along with data on richness of intra- and extracellular infectious organisms. Using Bayesian phylogenetic methods, we found that primate species with higher overall helminth prevalence harbored more species of intracellular Microparasites, while the positive association between helminth prevalence and extracellular Microparasite species richness was weaker. The relationships held after controlling for potentially confounding variables, but associations were not found in focused tests of prevalence for six genera of well-studied helminths. The magnitude of support and effect sizes for overall helminth prevalence on intracellular Microparasite species richness was similar to support for other well recognized ecological and life history drivers of parasite species richness. Our findings therefore suggest that intra-host parasite interactions are as important as some ecological characteristics of hosts in accounting for parasite richness across host species
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Hidden Consequences of Living in a Wormy World: Nematode‐Induced Immune Suppression Facilitates Tuberculosis Invasion in African Buffalo
ScholarWorks at University of Montana, 2010Co-Authors: Ezenwa, Vanessa O., Etienne, Rampal S., Luikart Gordon, Beja-pereira Albano, Jolles, Anna E.Abstract:Most hosts are infected with multiple parasites, and responses of the immune system to co-occurring parasites may influence disease spread. Helminth infection can bias the host immune response toward a T-helper type 2 (Th2) over a type 1 (Th1) response, impairing the host’s ability to control concurrent intracellular Microparasite infections and potentially modifying disease dynamics. In humans, immune-mediated interactions between helminths and Microparasites can alter host susceptibility to diseases such as HIV, tuberculosis (TB), and malaria. However, the extent to which similar processes operate in natural animal populations and influence disease spread remains unknown.We used cross-sectional, experimental, and genetic studies to show that gastrointestinal nematode infection alters immunity to intracellular Microparasites in free-ranging African buffalo (Syncerus caffer). Buffalo that were more resistant to nematode infection had weaker Th1 responses, there was significant genotypic variation in nematode resistance, and anthelminthic treatment enhanced Th1 immunity. Using a disease dynamic model parameterized with empirical data, we found that nematode-induced immune suppression can facilitate the invasion of bovine TB in buffalo. In the absence of nematodes, TB failed to invade the system, illustrating the critical role nematodes may play in disease establishment. Our results suggest that helminths, by influencing the likelihood of Microparasite invasion, may influence patterns of disease emergence in the wild
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Hidden Consequences of Living in a Wormy World: Nematode-Induced Immune Suppression Facilitates Tuberculosis Invasion in African Buffalo
'University of Chicago Press', 2010Co-Authors: Ezenwa, Vanessa O., Etienne, Rampal S., Luikart Gordon, Beja-pereira Albano, Jolles, Anna E.Abstract:Most hosts are infected with multiple parasites, and responses of the immune system to co occurring parasites may influence disease spread. Helminth infection can bias the host immune response toward a T-helper type 2 Th2) over a type 1 Th1) response, impairing the host's ability to control concurrent intracellular Microparasite infections and potentially modifying disease dynamics. In humans, immune-mediated interactions between helminths and Microparasites can alter host susceptibility to diseases such as HIV, tuberculosis TB), and malaria. However, the extent to which similar processes operate in natural animal populations and influence disease spread remains unknown. We used cross-sectional, experimental, and genetic studies to show that gastrointestinal nematode infection alters immunity to intracellular Microparasites in free-ranging African buffalo Syncerus caffer). Buffalo that were more resistant to nematode infection had weaker Th1 responses, there was significant genotypic variation in nematode resistance, and anthelminthic treatment enhanced Th1 immunity. Using a disease dynamic model parameterized with empirical data, we found that nematode-induced immune suppression can facilitate the invasion of bovine TB in buffalo. In the absence of nematodes, TB failed to invade the system, illustrating the critical role nematodes may play in disease establishment. Our results suggest that helminths, by influencing the likelihood of Microparasite invasion, may influence patterns of disease emergence in the wild
Vanessa O Ezenwa - One of the best experts on this subject based on the ideXlab platform.
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hidden consequences of living in a wormy world nematode induced immune suppression facilitates tuberculosis invasion in african buffalo
The American Naturalist, 2010Co-Authors: Vanessa O Ezenwa, Rampal S. Etienne, Albano Bejapereira, Gordon Luikart, Anna E. JollesAbstract:Abstract: Most hosts are infected with multiple parasites, and responses of the immune system to co‐occurring parasites may influence disease spread. Helminth infection can bias the host immune response toward a T‐helper type 2 (Th2) over a type 1 (Th1) response, impairing the host’s ability to control concurrent intracellular Microparasite infections and potentially modifying disease dynamics. In humans, immune‐mediated interactions between helminths and Microparasites can alter host susceptibility to diseases such as HIV, tuberculosis (TB), and malaria. However, the extent to which similar processes operate in natural animal populations and influence disease spread remains unknown. We used cross‐sectional, experimental, and genetic studies to show that gastrointestinal nematode infection alters immunity to intracellular Microparasites in free‐ranging African buffalo (Syncerus caffer). Buffalo that were more resistant to nematode infection had weaker Th1 responses, there was significant genotypic variati...