Browsing by Author "Sabuni, Christopher A."

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Density dependence and persistence of Morogoro arenavirus transmission in a fluctuating population of its reservoir host
(British Ecological Society, 2019-07-21) Mariën, Joachim; Borremans, Benny; Verhaeren, Christophe; Kirkpatrick, Lucinda; Gryseels, Sophie; Bellocq, Joëlle Goüy de; Günther, Stephan; Sabuni, Christopher A.; Massawe, Apia W.; Reijniers, Jonas; Leirs, Herwig
A key aim in wildlife disease ecology is to understand how host and parasite characteristics influence parasite transmission and persistence. Variation in host population density can have strong impacts on transmission and outbreaks, and theory predicts particular transmission–density patterns depending on how para- sites are transmitted between individuals. Here, we present the results of a study on the dynamics of Morogoro arenavirus in a population of multimammate mice (Mastomys natalensis). This widespread African rodent, which is also the reservoir host of Lassa arenavirus in West Africa, is known for its strong seasonal density fluctuations driven by food availability. We investigated to what degree virus transmission changes with host population density and how the virus might be able to persist during periods of low host density.A seven‐year capture–mark–recapture study was conducted in Tanzania where rodents were trapped monthly and screened for the presence of antibodies against Morogoro virus. Observed seasonal seroprevalence patterns were com- pared with those generated by mathematical transmission models to test different hypotheses regarding the degree of density dependence and the role of chroni- cally infected individuals. We observed that Morogoro virus seroprevalence correlates positively with host density with a lag of 1–4 months. Model results suggest that the observed sea- sonal seroprevalence dynamics can be best explained by a combination of verti- cal and horizontal transmission and that a small number of animals need to be infected chronically to ensure viral persistence. Transmission dynamics and viral persistence were best explained by the existence of both acutely and chronically infected individuals and by seasonally changing transmission rates. Due to the presence of chronically infected rodents, rodent control is unlikely to be a feasible approach for eliminating arenaviruses such as Lassa virus from Mastomys populations.
Development of eight polymorphic microsatellite markers in the Black and Rufous sengi, Rhynchocyon petersi
(Conservation Genetics Resources, 2014-09) Sabuni, Christopher A.; Houtte, Natalie Van; Maganga, Samwel L. S.; Makundi, Rhodes H.; Leirs, Herwig; Bellocq, Joelle Gouy de
The Black and Rufous sengi, Ryhnchocyon petersi, is endemic to a limited range in East Africa. We report the development of eight polymorphic microsatellites using next generation sequencing technology. Eighteen individuals from Zaraninge forest (Saadani National Park, Tanzania) were genotyped. The number of alleles per locus ranged from 2 to 6, while the observed and expected heterozygosities varied from 0.17 to 0.82 and from 0.25 to 0.81, respectively. No locus deviated from Hardy–Weinberg equilibrium. These microsatellite markers will be useful tools to study the effect of habitat fragmentation on the population genetic structure of R. petersi.
Distribution and ecology of lesser pouched rat, Beamys hindei, in Tanzanian coastal forests
(Integrative Zoology, 2015) Sabuni, Christopher A.; Sluydts, Vincent; Mulungu, Loth S.; Maganga, Samwel L.S.; Makundi, Rhodes H.; Leirs, Herwig
The lesser pouched rat, Beamys hindei, is a small rodent that is patchily distributed in the Eastern Arc Mountains and coastal forests in East Africa. The ecology of this species and its current distribution in coastal forests is not well known. Therefore, we conducted a study in selected coastal forests to assess the current distribution of the species and to investigate the population ecology in terms of abundance fluctuations and demographic patterns. Assessments of the species distribution were conducted in 5 forests through trapping with Sherman live traps. Data on ecology were obtained from monthly capture–mark–recapture studies conducted for 5 consecutive nights per month in two 1 ha grids set in Zaraninge Forest over a 2-year period. The results indicate the presence of B. hindei in 3 forests where it was not previously recorded. The population abundance estimates ranged from 1 to 40 animals per month, with high numbers recorded during rainy seasons. Reproduction patterns and sex ratios did not differ between months. Survival estimates were not influenced by season, and recruitment was low, with growth rate estimates of 1 animal per month. These estimates suggest a stable population of B. hindei in Zaraninge Forest. Further studies are recommended to establish the home range, diet and burrowing behavior of the species in coastal forests in East Africa.
Rodent species composition, relative abundance, and habitat association in the Mabira Central Forest Reserve, Uganda
(Institute of Vertebrate Biology, Czech Academy of Sciences, 2020-10-15) Ssuuna, James; Makundi, Rhodes H.; Isabirye, Moses; Sabuni, Christopher A.; Babyesiza, Waswa S.; Mulungu, Loth S.
A study was conducted in Mabira Central Forest Reserve in Uganda to determine rodent species composition, relative abundance, and habitat association. A total of 1,030 rodents belonging to 14 species were captured on 10,584 trap nights. Rodent species recorded include: Lophuromys stanleyi, Hylomyscus stella, Praomys jacksoni, Mastomys natalensis, Lophuromys ansorgei, Lemniscomys striatus, Aethomys hindei, Mus triton, Mus minutoides, Deomys ferrugineus, Gerbilliscus kempi, Rattus rattus, Grammomys kuru, and Hybomys univittatus. Overall, L. stanleyi (23.7%) was the most dominant species followed by H. stella, P. jacksoni, and M. natalensis. Species richness and evenness was highest in the regenerating forest habitat and least in the intact forest habitat. Rodent abundance was significantly affected by habitat type. The regenerating forest habitat had the highest number of animals, while the lowest numbers were observed in the depleted forest habitat. Species diversity was higher in regenerating forest habitat and lowest in the intact forest. The three habitats appeared distinct in terms of rodent species composition and there was a strong association between the two trapping grids in the same habitat type. All ordination plots showed that different rodent species consistently associated with distinct habitats. Habitat type and seasonal changes influenced rodent composition, relative abundance and habitat association. Composition of rodent community reflected the level of habitat degradation and can be used as a proxy for evaluating the biodiversity of lowland tropical forests.
Subspecific rodent taxa as the relevant host taxonomic level for mammarenavirus host specificity
(Elsevier Inc., 2023) Cuypers, Laura N.; Gryseels, Sophie; Baird, Stuart J.E.; Sabuni, Christopher A.; Katakweba, Abdul S.; van den Burg, Sebastiaan R.M.; Bryja, Josef; Leirs, Herwig; de Bellocq, Joëlle Goüy
Mastomys natalensis-borne mammarenaviruses appear specific to subspecific M. natalensis taxa rather than to the whole species. Yet mammarenaviruses carried by M. natalensis are known to spill over and jump hosts in northern sub-Saharan Africa. Phylogeographic studies increasingly show that, like M. natalensis, small mammals in sub- Saharan Africa are often genetically structured into several subspecific taxa. Other mammarenaviruses may thus also form virus-subspecific host taxon associations. To investigate this, and if mammarenaviruses carried by M. natalensis in southern Africa are less prone to spill-over, we screened 1225 non-M. natalensis samples from Tanzania where many small mammal taxa meet. We found mammarenavirus RNA in 6 samples. Genetic/genomic characterisation confirmed they were not spill-over from M. natalensis. We detected host jumps among rodent tribe members and an association between mammarenaviruses and subspecific taxa of Mus minutoides and Grammomys surdaster, indicating host genetic structure may be crucial to understand virus distribution and host specificity.