Browsing by Author "Holmes, Jennifer L."

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    Early-phase Transmission of Yersinia pestis by Cat Fleas (Ctenocephalides felis) and Their Potential Role as Vectors in a Plague-endemic Region of Uganda
    (The American journal of tropical medicine and hygiene, 2008) Eisen, Rebecca J.; Borchert, Jeff N.; Holmes, Jennifer L.; Amatre, Gerald; Van Wyk, Kristen; Enscore, Russell E.; Babi, Nackson; Atiku, Linda A.; Wilder, Aryn P.; Vetter, Sara M.; Bearden, Scott W.; Montenieri, John A.; Gage, Kenneth L.
    In recent decades, the majority of human plague cases (caused by Yersinia pestis) have been reported from Africa. In northwest Uganda, which has had recent plague outbreaks, cat fleas (Ctenocephalides felis) have been reported as the most common fleas in the home environment, which is suspected to be a major exposure site for human plague in this country. In the past, C. felis has been viewed as only a nuisance-biting insect because limited laboratory studies suggested it is incapable of transmitting Y. pestis or is an inefficient vector. Our laboratory study shows that C. felis is a competent vector of plague bacteria, but that efficiency is low compared with another flea species collected in the same area: the oriental rat flea, Xenopsylla cheopis. On the other hand, despite its low vector efficiency, C. felis is the most common flea in human habitations in a plague-endemic region of Uganda (Arua and Nebbi Districts), and occasionally infests potential rodent reservoirs of Y. pestis such as the roof rat (Rattus rattus) or the Nile rat (Arvicanthisniloticus). Plague control programs in this region should remain focused on reducing rat flea populations, although our findings imply that cat fleas should not be ignored by these programs as they could play a significant role as secondary vectors.
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    Evaluation and Modification of Off-Host Flea Collection Techniques Used in Northwest Uganda: Laboratory and Field Studies
    (Journal of medical entomology, 2012) Borchert, Jeff N.; Eisen, Rebecca J.; Holmes, Jennifer L.; Atiku, Linda A.; Mpanga, Joseph T.; Brown, Heidi E.; Graham, Christine B.; Babi, Nackson; Montenieri, John A.; Enscore, Russell E.; Gage, Kenneth L.
    Quantifying the abundance of host-seeking ßeas is critical for assessing risk of human exposure to ßea-borne disease agents, including Yersinia pestis, the etiological agent of plague. Yet, reliable measures of the efÞcacy of existing host-seeking ßea collection methods are lacking. In this study, we compare the efÞcacy of passive and active methods for the collection of host-seeking ßeas in both the laboratory and human habitations in a plague-endemic region of northwest Uganda. In the laboratory, lighted “Kilonzo” ßea traps modiÞed with either blinking lights, the creation of shadows or the generation of carbon dioxide were less efÞcient at collecting Xenopsylla cheopis Rothchild and Ctenocephalides felis Bouche´ ßeas than an active collection method using white cotton socks or cotton ßannel. Passive collection using Kilonzo light traps in the laboratory collected signiÞcantly more X. cheopis than C. felis and active collection, using white socks and ßannel, collected signiÞcantly more C. felis than X. cheopis. In Þeld studies conducted in Uganda, Kilonzo traps using a ßashlight were similar in their collection efÞcacy to Kilonzo traps using kerosene lamps. However, in contrast to laboratory studies, Kilonzo ßea traps using ßashlights collected a greater number of ßeas than swabbing. Within human habitations in Uganda, Kilonzo traps were especially useful for collecting C. felis, the dominant species found in human habitations in this area.