Epidemiology, Ecology and Prevention of Plague in the West Nile Region of Uganda: The Value of Long-Term Field Studies

Eisen, Rebecca J.; Atiku, Linda A.; Enscore, Russell E.; Mpanga, Joseph T.; Acayo, Sarah; Mead, Paul S.; Apangu, Titus; Yockey, Brook; Borchert, Jeff N.; Beard, Charles B.; Gage, Kenneth L.

doi:10.4269/ajtmh.20-1381

Cited by 6 publications

(3 citation statements)

References 32 publications

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“…Although the frequency of plague outbreaks in the country has decreased compared to the past, the conditions still provide a conducive environment for future occurrences [10]. Moreover, an increasing association between persistence of plague and social and environmental factors has been observed not only in Tanzania [7,10], but also in other countries such as Peru, Zambia and Uganda [11][12][13]. This highlights the need for understanding how human practices and behaviour in their surroundings influence the continued existence of plague.…”

Section: Introductionmentioning

confidence: 99%

Knowledge and practices related to plague persistence in plague-endemic foci, Mbulu District, Tanzania

Kessy,

Rija

2024

PLoS Negl Trop Dis

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Introduction Plague continues to be a major public health concern in African countries. Several social practices and environmental conditions have been associated with the reoccurrence of bubonic plague, especially in places where the disease is prevalent. Therefore, it remains important to understand people knowledge, behavior and practices related to disease risks in order to identify factors that may hinder prevention and control strategies in the foci. Methods and results A study survey of 100 households was conducted in Mbulu district to assess plague knowledge, factors that influence flea bite and measures used for rodent and flea control. Majority of participants (86%) were familiar with the plague disease and about (50%) mentioned swelling lymph nodes as a common symptom. Most of the participants (62%) claimed to observe human plague cases during the long rain season. The majority of participants (97%) reported to experience flea bite in their domestic settings, with most stating that they experienced more flea bites during the dry season. Houses with livestock had a greater likelihood of flea bite (OR = 2.7; 95% CI: 0.36–18.80, p = 0.267) compared to houses with no livestock. Furthermore, residents reported using both local and chemical methods to control rodents and flea inside houses. Most respondents preferred using local methods in flea control. Respondents stated that the efficacy of flea control methods being applied ranged from few days to several months. There was limited knowledge of the residual effects of the agricultural chemicals being used to control fleas among the surveyed community. Conclusion Our study highlights the importance of raising awareness and adopting effective control methods for controlling fleas and lower the risk of plague transmission and other flea borne diseases in the local communities. Sensitization of the local community on the use of appropriate chemicals for flea control is urgent to avoid any potential long-term impacts of the residual effects on the health of the local communities.

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Section: Introductionmentioning

confidence: 99%

Knowledge and practices related to plague persistence in plague-endemic foci, Mbulu District, Tanzania

Kessy,

Rija

2024

PLoS Negl Trop Dis

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“…Plague, caused by Yersinia pestis, is a ea-borne bacterial zoonosis that is often fatal if appropriate antibiotic treatment is inadequate or delayed [12]. The majority of human plague cases in recent decades have occurred in Africa [13]. In Uganda, the West Nile region represents the primary epidemiologic foci where 255 human plague cases were reported between 2008-2016 [14].…”

Section: Introductionmentioning

confidence: 99%

Molecular detection and characterization of emerging pathogens of Rickettsia- felis and felis-like organisms from peri-domestic fleas in Uganda

Eneku

Erima

Byaruhanga

et al. 2023

Preprint

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Background: Flea-borne spotted fever is an emerging zoonosis caused by Rikecttsia felis, a Gram-negative obligate intracellular bacterium. The agent is believed to be cosmopolitan, following the distribution pattern of its host and reservoir, Ctenocephalides felis. However, the epidemiology and public health risk it poses remains poorly understood in sub-Saharan Africa, including Uganda. Yersinia pestis, is primarily transmitted by rodent fleas, Xenopsylla cheopis, but other fleas, particularly C. felis, have vectoral capacity. They are neglected in Ugandan entomological surveillance and public health practices, particularly outside endemic foci of bubonic plague. Methods: We collected 14,641 fleas from domestic animals, rodents and homestead environment; compared their diversity and abundance. Pooled into 714 flea pools by species, collection time, host, and host species, 172 pools were selected based on seasons and analyzed for Yersinia pestis Pla genes, while 62 pools were tested for Rickettsia species gltA, ompA, and 17kDA genes by qPCR and Sanger sequencing. Results: Five flea species were identified from the collections: Ctenocephalides canis, C. felis, Echidnophaga gallinacea, Pulex irritans, and Xenopsylla cheopis. Ctenocephalides was the predominant genus, accounting for 84.8% of fleas collected, mostly found on dogs and goats. Except for P. irritans (which was found in Gulu district) the other four flea species were found across all districts, year-round, with higher numbers collected in dry seasons compared to rainy seasons (c2=47.64, df=20, p<0.001). Rattus rattus constituted 74% of rodents captured from human dwellings and was the only rodent species with fleas, where X. cheopis was the predominant species and E. gallinacea found on only three rodents. All 172 pools of fleas tested negative for Yersinia pestis. Of the 62 pools tested for Rickettsia spp., 29 (46.8%) were positive. Twenty-five PCR amplicons were successfully sequenced for 17kDa and two for ompA genes. Based on 17kDa, two were identified as R. felis from C. canis and 23 were R. asembonensis from multiple flea species, including C. canis collected goats and C. felis from cats. Conclusion: Our survey identified a high pooled detection rate (~50%) of Rickettsia spp. in fleas tested, suggesting a potential risk of human exposure and infection. Rickettsia felis and R. asembonensis were the predominant flea-borne Rickettsia spp. identified, with this study also representing the first report of Rickettsia spp. in E. gallinacea in Uganda.

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“…These strategies include monitoring plague host abundance, host mortality (die-offs or rat falls), flea loads on rodents, seropositivity of non-human hosts, or direct detection of Y. pestis in vectors or rodent hosts ( Borchert et al, 2012 ; Moore et al, 2015 ; Boegler et al, 2018 ; Ehlers et al, 2020 ). The most effective and reliable strategies are dependent on accurate detection of Y. pestis ( Eisen et al, 2020 , 2021 ).…”

Section: Introductionmentioning

confidence: 99%

A Novel Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Yersinia pestis

Bai

Rizzo²,

Parise³

et al. 2022

Front. Microbiol.

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Rapid detection of Yersinia pestis, the causative agent of plague, is essential during field investigations to enable prompt control measures for prevention of the spread of the disease. Affordable, efficient, reliable, and simple detection assays are extremely useful, particularly in plague-endemic regions with limited resources. We developed a loop-mediated isothermal amplification (LAMP) assay that detects Y. pestis within 30 min by simply incubating at 65°C on a dry bath heater. The assay targeted the caf1A gene that is situated on the pMT1 plasmid using six specific primers. Y. pestis presence is visually detected based on the color change in the reactions. For comparison of the assay performance, a real-time LAMP with fluorescent dye detection was conducted on a real-time PCR instrument using the same six primers. Sensitivity assessment showed that the limit of detection (LOD) was 0.2 and 0.03 pg when performed on the dry bath heater and on the real-time PCR instrument, respectively. The assay was 100% specific, having no cross-reactivity with closely related Yersinia spp. and other bacterial species. We tested the LAMP assay on field-collected fleas and showed that it successfully detected Y. pestis with identical results to that of a previously published pentaplex real-time PCR assay. These findings suggest that the relatively inexpensive and simpler LAMP assay could be used to support field investigations, yielding comparable results to more expensive and complex PCR assays.

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Epidemiology, Ecology and Prevention of Plague in the West Nile Region of Uganda: The Value of Long-Term Field Studies

Cited by 6 publications

References 32 publications

Knowledge and practices related to plague persistence in plague-endemic foci, Mbulu District, Tanzania

Knowledge and practices related to plague persistence in plague-endemic foci, Mbulu District, Tanzania

Molecular detection and characterization of emerging pathogens of Rickettsia- felis and felis-like organisms from peri-domestic fleas in Uganda

A Novel Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Yersinia pestis

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