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Published on: August 31, 2013
Transovarial transmission of Yersinia pestis in its flea vector Xenopsylla cheopis
Cassandra D Pauling1,2, Brenda T Beerntsen1, Qisheng Song3
1Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA.
Abstract:
Yersinia pestis, the causative agent of plague, is endemic in certain regions due to a stable transmission cycle between rodents and their associated fleas. In addition, fleas are believed to serve as reservoirs that can occasionally cause enzootic plague cycles and explosive epizootic outbreaks that increase human exposure. However, transmission by fleas is inefficient and associated with a shortened lifespan of the flea and rodent hosts, indicating that there remain significant gaps in our understanding of the vector-animal cycle of Y. pestis. Here, we show that laboratory-reared, infected fleas (Xenopsylla cheopis) can transmit viable Y. pestis from adults to eggs, and the bacteria can be passed through all subsequent life stages of the flea. Thus, our data raise the possibility that transovarial transmission in fleas might contribute to the persistence of Y. pestis in the environment without detectable plague activity in mammals.
Insights
Fleas can pass Yersinia pestis bacteria to their eggs, enabling transmission through all life stages. This transovarial transmission may explain plague persistence in the environment without mammal involvement.
Area of Science:
- * Vector-borne disease ecology
- * Bacteriology and microbial pathogenesis
- * Epidemiology of infectious diseases
Background:
- * Yersinia pestis causes plague, a disease endemic in many regions, with transmission cycles involving rodents and fleas.
- * Fleas are suspected reservoirs for Y. pestis, potentially causing enzootic cycles and epizootic outbreaks, increasing human exposure risks.
- * Current understanding of Y. pestis transmission by fleas is incomplete, with observed inefficiencies and host lifespan reductions.
Purpose of the Study:
- * To investigate the potential for Yersinia pestis transmission from adult fleas to their eggs.
- * To determine if viable Y. pestis can be passed through all subsequent flea life stages.
- * To explore the role of transovarial transmission in the environmental persistence of Y. pestis.
Main Methods:
- * Laboratory rearing of infected fleas (Xenopsylla cheopis).
- * Monitoring of Yersinia pestis viability and transmission through successive flea generations.
- * Analysis of bacterial presence across all flea life stages, from egg to adult.
Main Results:
- * Viable Yersinia pestis was successfully transmitted from infected adult fleas to their eggs.
- * The bacteria were detected and maintained through all subsequent flea life stages.
- * Evidence suggests fleas can serve as a persistent reservoir for Y. pestis.
Conclusions:
- * Transovarial transmission of Yersinia pestis by fleas is a viable mechanism.
- * This transmission route may contribute to the environmental persistence of Y. pestis.
- * Plague may persist in the environment independent of active mammalian hosts, mediated by infected fleas.
