Browsing by Author "Amatre, Gerald"

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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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    Flea Diversity and Infestation Prevalence on Rodents in a Plague-Endemic Region of Uganda
    (The American journal of tropical medicine and hygiene, 2009) Amatre, Gerald; Babi, Nackson; Enscore, Russell E.; Ogen-Odoi, Asaph; Atiku, Linda A.; Akol, Anne; Gage, Kenneth L.; Eisen, Rebecca J.
    In Uganda, the West Nile region is the primary epidemiologic focus for plague. The aims of this study wereto 1) describe flea–host associations within a plague-endemic region of Uganda, 2) compare flea loads between villages with or without a history of reported human plague cases and between sampling periods, and 3) determine vector loads on small mammal hosts in domestic, peridomestic, and sylvatic settings. We report that the roof rat, Rattusrattus, is the most common rodent collected in human dwellings in each of the 10 villages within the two districts sampled. These rats were commonly infested with efficient Y. pestis vectors, Xenopsylla cheopis and X. brasiliensis in Arua and Nebbi districts, respectively. In peridomestic and sylvatic areas in both districts, the Nile rat, Arvicanthus niloticus, was the most abundant rodent and hosted the highest diversity of flea species. When significant temporal differences in flea loads were detected, they were typically lower during the dry month of January. We did not detect any significant differences in small mammal abundance or flea loads between villages with our without a history of human plague, indicating that conditions during inter-epizootic periods are similar between these areas. Future studies are needed to determine whether flea abundance or species composition changes during epizootics when humans are most at risk of exposure.
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    Jigger Flea (Tunga penetrans) Infestations and Use of Soil-Cow Dung-Ash Mixture as a Flea Control Method in Eastern Uganda
    (International Journal of Agricultural and Biosystems Engineering, 2018) Amatre, Gerald; Lejju, Julius B.; Andama, Morgan
    Despite several interventions, jigger flea infestations continue to be reported in the Busoga sub-region in Eastern Uganda. The purpose of this study was to identify factors that expose the indigenous people to jigger flea infestations and evaluate the effectiveness of any indigenous materials used in flea control by the affected communities. Flea compositions in residences were described, factors associated with flea infestation and indigenous materials used in flea control were evaluated. Field surveys were conducted in the affected communities after obtaining preliminary information on jigger infestation from the offices of the District Health Inspectors to identify the affected villages and households.Informed consent was then sought from the local authorities and household heads to conduct the study. Focus group discussions were conducted with key district informants, namely, the District Health Inspectors, District Entomologists and representatives from the District Health Office. A GPS coordinate was taken at central point at every household enrolled. Fleas were trapped inside residences using Kilonzo traps. A Kilonzo Trap comprised a shallow pan, about three centimetres deep, filled to the brim with water. The edges of the pan were smeared with Vaseline to prevent fleas from crawling out. Traps were placed in the evening and checked every morning the following day. The trapped fleas were collected in labelled vials filled with 70% aqueous ethanol and taken to the laboratory for identification. Socioeconomic and environmental data were collected. The results indicate that the commonest flea trapped in the residences was the cat flea (Ctenocephalides felis) (50%), followed by Jigger flea (Tunga penetrans) (46%) and rat flea (Xenopsylla Cheopis) (4%), respectively. The average size of residences was seven squire metres with a mean of six occupants. The residences were generally untidy; with loose dusty floors and the brick walls were not plastered. The majority of the jigger affected households were headed by peasants (86.7%) and artisans (13.3%). The household heads mainly stopped at primary school level (80%) and few at secondary school level (20%). The jigger affected households were mainly headed by peasants of low socioeconomic status. The affected community members use soil-cow dung-ash mixture to smear floors of residences as the only measure to control fleas. This method was found to be ineffective in controlling the insects. The study recommends that home improvement campaigns be continued in the affected communities to improve sanitation and hygiene in residences as one of the interventions to combat flea infestations. Other cheap, available and effective means should be identified to curb jigger flea infestations.
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    Prevalence of Jigger Flea (Tunga Penetrans) Infestation amongst Age Groups, Male and Female Persons in Jinja District, Eastern Uganda
    (International Journal of Science and Research, 2018) Amatre, Gerald; Lejju, Julius Bunny; Andama, Morgan
    Jigger flea infestations are endemic in several rural communities in Uganda. The Eastern part of the country reports outbreaks of jigger infestations. This case study was carried out to identify the most vulnerable sex and age groups to jigger infestation so that appropriate control measures can be recommended. Members of the affected communities in Jinja district were requested to report households that had current cases of jigger infestation. The name, sex and age of the household heads and infected persons were recorded. Details of the persons were then removed from the lists for ethical reasons. A total of 429 persons were reported to be infested with jiggers in nine parishes of five sub-counties in the district. There was a significant difference in jigger infestation in different age groups (p=8E-152, χ2 = 712.79) and between males and females (p=2.88E-8, χ2=30.78). The most infested age group (n, %) was below 15years (269, 62.7%), followed by the elderly people, above 55 years (48, 11.2%) and the least infested age group was 16-25 years (8, 1.9%). Males in each age category were at least twice more infested with jiggers than females. The study recommends that more attention be focused on children, elderly persons and males in jigger control than on females and persons in other age groups.