Browsing by Author "Rija, Alfan"

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Ecological and environmental conditions correlate with flea population within human habitations in a plague focus, Mbulu district, Tanzania
(PLOS Global Public Health, 2025-06-18) Kessy, Stella; Rija, Alfan
Plague persistence remains a major health concern in some African countries. Although the role of some flea vectors in their transmission is widely known, the local-scale factors contributing to human plague recurrence are still poorly understood, thwarting the potential disease mitigation measures in affected communities. We examined the flea population and their relationship to household practices in rural Mbulu District, northern Tanzania. We sampled fleas from both host (170 rodents in 3 species) and household interiors using a Light trap (Ltrap). We found seven species of flea inhabiting the human dwelling, with Xenopsylla brasilliensis the most common species occupying rodent species and the in-house environment. Dinopsylla lypusus and three others: Ctenocephalides canis, Ctenocephalides felis and Xenopsylla cheopis, partitioned between the rodents and the house environment, espectively, indicating niche separation and distinct disease transmission risks in these vectors. Further, the flea index varied throughout the sampling period, with the total flea index exceeding the threshold of 1. We observed that X. brasilliensis (mean = 1.93 ± 0.56SE, p < 0.001) significantly increased the abundance of rodent fleas. Furthermore, households without keeping livestock under the same roof (mean = - 0.97 ± 0.16SE, p < 0.001) and not owning livestock (mean = -1. 45 ± 0.31SE, p < 0.001) had a higher likelihood of decreased house flea population than households sharing livestock under one roof. Similarly, houses with bed arrangements with a sleeping loft positively correlated with increased rodent flea abundance (mean = 1.88 ± 1.04SE, p = 0.07), strongly suggesting the importance of improving rural lifestyle. Enhancing public education on hygiene and flea control measures to reduce the risks of plague persistence and transmission in these rural communities is an increasing priority
Flea infestation of rodent and their community structure in frequent and non-frequent plague outbreak areas in Mbulu district, northern Tanzania
(Elsevier, 2024-03-04) Kessy, Stella; Makundi, RhodesH.; Massawe, Apia; Rija, Alfan
Understanding rodent-ectoparasite interactions and the factors driving them is important in understanding the epidemiology of diseases involving an arthropod vector. Fleas are the primary vector for Yersinia pestis, the bacteria that causes plague and monitoring of flea population is essential for planning the potential mitigation measures to prevent the disease outbreak. In this study, we investigated flea abundance, community structure and the potential factors driving flea infestation in areas with frequent (persistent) and non-frequent plague (non- persistent) outbreaks. We collected fleas from captured rodents in two villages with both forest and farm hab- itats. We found 352 fleas belonging to 5 species with Dinopsyllus lypusus the most abundant overall (57.10%) and Ctenophthalmus spp. the lowest (1.70%). There were no significant differences of flea abundance between study localities, habitats and seasons (p > 0.05) but, flea infestation was significantly positively associated with the persistent locality and with the short rain season (p < 0.05). Further, flea abundance increased significantly with rodent body weight (p < 0.05). Furthermore, we found fleas broadly structured into two communities varying between the dry, long rain and short rain seasons. These findings have important implications for public health, as they may be used to assess and control the risks of plague transmission and other flea borne diseases in the foci.
International Journal for Parasitology: Parasites and Wildlife
(ELSEVIER, 2024-03-04) Kessy, Stella; Makundi, RhodesH.; Massawe, Apia; Rija, Alfan
Understanding rodent-ectoparasite interactions and the factors driving them is important in understanding the epidemiology of diseases involving an arthropod vector. Fleas are the primary vector for Yersinia pestis, the bacteria that causes plague and monitoring of flea population is essential for planning the potential mitigation measures to prevent the disease outbreak. In this study, we investigated flea abundance, community structure and the potential factors driving flea infestation in areas with frequent (persistent) and non-frequent plague (non- persistent) outbreaks. We collected fleas from captured rodents in two villages with both forest and farm hab- itats. We found 352 fleas belonging to 5 species with Dinopsyllus lypusus the most abundant overall (57.10%) and Ctenophthalmus spp. the lowest (1.70%). There were no significant differences of flea abundance between study localities, habitats and seasons (p > 0.05) but, flea infestation was significantly positively associated with the persistent locality and with the short rain season (p < 0.05). Further, flea abundance increased significantly with rodent body weight (p < 0.05). Furthermore, we found fleas broadly structured into two communities varying between the dry, long rain and short rain seasons. These findings have important implications for public health, as they may be used to assess and control the risks of plague transmission and other flea borne diseases in the foci.
Knowledge and practices related to plague persistence in plague-endemic foci, Mbulu District, Tanzania
(Public Library of Science, 2024-05-30) Kessy, Stella; Rija, Alfan
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.
Pattern and composition of wildlife roadkill across urban-rural gradient in an African expanding city
(Springer Nature Link, 2024-10-02) Mariki, Heavenlight; Kessy, Stella; Byamungu, Robert; Rija, Alfan
Urban roads are known to affect wildlife fauna but most assessments of the impacts of roads have been done in cities of the developed world with comparable studies still lacking from sprawling cities of the developing countries. This gap precludes the ability of the city management authorities in designing the appropriate mitigation and conservation measures especially during this era where the road networks in African cities is expanding steadily. We surveyed 48 km of roads transcending an urban-rural gradient in Morogoro city, Tanzania to understand the patterns of road kills, taxonomic composition and used the Generalized linear modeling to determine the ecological and environmental factors mostly influencing the road kill abundances. We also assessed the conservation status of the road kills to propose measures to improve biodiversity conservation in this urban landscape bordering a global biodiversity hotspot. We found 929 killed animals belonging to 62 families and 23 orders and 5 taxa (classes) with the majority kills being insects. There was a significant difference on road kill abundance between taxa but no significant difference in kill abundance across the urban-rural gradient. Furthermore, we found that designated road speed limit was significantly positively associated with increased road kills with the insect taxon occurring most abundant in the kill. Additionally, we found three species involved in the animal-vehicle collision threatened with extinction and over 50% of the recorded road kills lacking information on their conservation status on the red list at all. These data may be useful in improving the strategies to reducing the animal-vehicle collisions and to inform the potential biodiversity monitoring in the study area and elsewhere in Africa’s cities faced with similar urbanization challenges.
Population dynamics of the Multimammate rat (Mastomys natalensis) and Makundi’s brush fur rat (Lophuromys makundii) and their implications in disease …
(Springer, 2024-03-06) Kessy, Stella; Sabuni, Christopher; Massawe, Apia; Makundi, Rhodes; Rija, Alfan
Understanding host population dynamics in connection to disease persistence is important for determining the epizootic risks present in plague foci. We used a capture-mark-recapture method to investigate the population dynamics of Mastomys natalensis and Lophuromys makundii in an active plague focus, in Mbulu District, Tanzania. We hypothesized higher abundance in plague-persistent locality and between habits and seasons. We found distinct patterns of abundance in M. natalensis between farm and forest habitats. The abundance was significantly higher in farms in plague persistent than non-plague persistent areas. The dry season showed a significant increase of abundance compared to the long rain season and the short rain season. A significant increase in breeding females was observed in farms in plague persistent than non-plague persistent localities while farms showed a significant decrease compared to forests. Dry season was associated with an increase in breeding females compared to the long rain season and the short rain season. Furthermore, the abundance of L. makundii showed a significant increase in forest in plague persistent than non-plague persistent localities. The abundance increased significantly during the dry season and long rain season compared to the short rain season. The proportion of breeding females was significantly higher in forests in plague persistent than non-plague persistent localities. The breeding females significantly increased during the dry and the short rain season than the long rain season. These findings contribute to our understanding of the ecological factors shaping the population dynamics of these species and their potential roles in plague persistence.
Rodent abundance, diversity and community structure in a bubonic plague endemic area, northern Tanzania
(De Gruyter, 2023-08-07) Kessy, Stella; Makundi, Rhodes; Sabuni, Christopher; Massawe, Apia; Rija, Alfan
Rodent-borne diseases such as bubonic plague remain a significant threat to public health in tropical countries. In plague-endemic areas, little information exists on the factors triggering periodic bursts, thus rendering preparedness strategies for preventing the negative impacts of the deadly zoonosis difficult. In this study, we assessed how species richness, diversity, and community structure of rodents are associated with plague persistence in Mbulu District, Tanzania. Rodent data were collected using the removal trapping technique. We captured 610 rodents belonging to 12 species, with Mastomys natalensis recording highest abundance. There was significantly higher abundance and species richness in persistent than non-persistent plague locality. Also, house premises recorded significantly lower species richness than farm and forest habitats. Additionally, we found three broad rodent community structures that varied significantly between studied habitat types suggesting high rodent populations interaction at fine-scale resource abundance. The high abundance and diversity of plague-susceptible rodent reservoirs suggestively contribute to the plague persistence in the foci. These results may be useful to developing preparedness strategies in these areas to control plague outbreaks.