Biomedical subjects

Amy B Pedersen

Publications and source records attributed to Amy B Pedersen.

3 recordsLinked to original sources

PubMed2006

Emphasizing the ecology in parasite community ecology.

In natural systems, individuals are often co-infected by many species of parasites. However, the significance of interactions between species and the processes that shape within-host parasite communities remain unclear. Studies of parasite community ecology are often descriptive, focusing on patterns of parasite abundance across host populations rather than on the mechanisms that underlie interactions within a host. These within-host interactions are crucial for determining the fitness and transmissibility of co-infecting parasite species. Here, we highlight how techniques from community ecology can be used to restructure the approaches used to study parasite communities. We discuss insights offered by this mechanistic approach that will be crucial for predicting the impact on wildlife and human health of disease control measures, climate change or novel parasite species introductions.

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PubMed2005

Patterns of host specificity and transmission among parasites of wild primates.

Multihost parasites have been implicated in the emergence of new diseases in humans and wildlife, yet little is known about factors that influence the host range of parasites in natural populations. We used a comprehensive data set of 415 micro- and macroparasites reported from 119 wild primate hosts to investigate broad patterns of host specificity. The majority (68%) of primate parasites were reported to infect multiple host species, including animals from multiple families or orders. This pattern corresponds to previous studies of parasites found in humans and domesticated animals. Within three parasite groups (viruses, protozoans and helminths), we examined parasite taxonomy and transmission strategy in relation to measures of host specificity. Relative to other parasite groups, helminths were associated with the greatest levels of host specificity, whereas most viruses were reported to infect hosts from multiple families or orders. Highly significant associations between the degree of host specificity and transmission strategy arose within each parasite group, but not always in the same direction, suggesting that unique constraints influence the host range of parasites within each taxonomic group. Finally characteristics of over 100 parasite species shared between wild primates and humans, including those recognised as emerging in humans, revealed that most of these shared parasites were reported from multiple host orders. Furthermore, nearly all viruses that were reported to infect both humans and non-human primates were classified as emerging in humans.

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PubMed2005

Community epidemiology framework for classifying disease threats.

Recent evidence suggests that most parasites can infect multiple host species and that these are primarily responsible for emerging infectious disease outbreaks in humans and wildlife. However, the ecologic and evolutionary factors that constrain or facilitate such emergences are poorly understood. We propose a conceptual framework based on the pathogen's between- and within-species transmission rates to describe possible configurations of a multihost-pathogen community that may lead to disease emergence. We establish 3 dynamic thresholds separating 4 classes of disease outcomes, spillover, apparent multi-host, true multihost, and potential emerging infectious disease; describe possible disease emergence scenarios; outline the population dynamics of each case; and clarify existing terminology. We highlight the utility of this framework with examples of disease threats in human and wildlife populations, showing how it allows us to understand which ecologic factors affect disease emergence and predict the impact of host shifts in a range of disease systems.

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