Browsing by Author "Leirs, Herwig"

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Application of normalized difference vegetation index (NDVI) to forecast rodent population abundance in smallholder agro-ecosystems in semi-arid areas in Tanzania
(ResearchGate, 2019-05) Hieronimo, Proches; Isabirye, Moses; Kifumba, David; Mulungu, Loth; Kimaro, Didas N; Makundi, Rhodes H.; Leirs, Herwig; Mulungu, Loth S.; Mdangi, Mashaka E.; Massawe, Apia W.
This study aimed to evaluate the potential use of normalized difference vegetation index (NDVI) from satellite- derived remote sensing data for monitoring rodent abundance in semi-arid areas of Tanzania. We hypothesized that NDVI could potentially complement rainfall in predicting rodent abundance spatially and tem- porally. NDVI were determined across habitats with differ- ent vegetation types in Isimani landscape, Iringa Region, in the southern highlands of Tanzania. Normalized differ- ences in reflectance between the red (R) (0.636–0.673 mm) and near-infrared (NIR) (0.851–0.879 mm) channels of the electromagnetic spectrum from the Landsat 8 [Opera- tional Land Imager (OLI)] sensor were obtained. Rodents were trapped in a total of 144 randomly selected grids each measuring 100 × 100 m 2 , for which the corresponding values of NDVI were recorded during the corresponding rodent trapping period. Raster analysis was performed by transformation to establish NDVI in study grids over the entire study area. The relationship between NDVI, rodent distribution and abundance both spatially and tempo- rally during the start, mid and end of the dry and wet sea- sons was established. Linear regression model was used to evaluate the relationships between NDVI and rodent abundance across seasons. The Pearson correlation coefficient (r) at p ≤ 0.05 was carried out to describe thedegree of association between actual and NDVI-predicted rodent abundances. The results demonstrated a strong linear relationship between NDVI and actual rodent abundance within grids (R 2 = 0.71). NDVI-predicted rodent abundance showed a strong positive correlation (r = 0.99) with estimated rodent abundance. These results support the hypothesis that NDVI has the potential for predicting rodent population abundance under smallholder farming agro-ecosystems. Hence, NDVI could be used to forecast rodent abundance within a reasonable short period of time when compared with sparse and not widely available rainfall data.h
Arenavirus dynamics in experimentally and naturally infected rodents
(EcoHealth Alliance, 2017-06) Marien, Joachim; Borremans, Benny; Gryseels, Sophie; Broecke, Bram Vanden; Becker-Ziaja, Beate; Makundi, Rhodes; Massawe, Apia; Reijniers, Jonas; Leirs, Herwig
Infectious diseases of wildlife are typically studied using data on antibody and pathogen levels. In order to interpret these data, it is necessary to know the course of antibodies and pathogen levels after infection. Such data are typically collected using experimental infection studies in which host individuals are inoculated in the laboratory and sampled over an extended period, but because laboratory conditions are controlled and much less variable than natural conditions, the immune response and pathogen dynamics may differ. Here, we compared Morogoro arenavirus infection patterns between naturally and experimentally infected multimammate mice (Mastomys natalensis). Longitudinal samples were collected during three months of bi-weekly trapping in Morogoro, Tanzania, and antibody titer and viral RNA presence were determined. The time of infection was estimated from these data using a recently developed Bayesian approach, which allowed us to assess whether the natural temporal patterns match the previously observed patterns in the laboratory. A good match was found for 52% of naturally infected individuals, while most of the mismatches can be explained by the presence of chronically infected individuals (35%), maternal antibodies (10%), and an antibody detection limit (25%). These results suggest that while laboratory data are useful for interpreting field samples, there can still be differences due to conditions that were not tested in the laboratory.
Community structure and seasonal abundance of rodents of maize farms in Southwestern Tanzania
(Belg. J. Zool, 2005-12) ODHIAMBO, Richard; Makundi, Rhodes; Leirs, Herwig; Verhagen, Ron
Community characteristics and seasonal abundance of rodents were investigated in a small-scale maize field-fallow land mosaic in southwestern Tanzania between February 2001 and May 2002. During the study, a total of 2568 rodents were captured in 9150 trapnights giving a 28 % trap success. Also shrews of the genus Croci- dura (Soricidae) were recorded. Mastomys natalensis comprised the highest proportion of rodents caught account- ing for 82.9 % of all captures. Other rodent genera captured included : Tatera, Saccostomus, Graphiurus, and Steat- omys. Relative densities as measured by both trap success and the number of rodents per hectare, and biomass varied between seasons with and without crop in the field but not between habitat types. The work reports seasonal- ity in breeding for the two most commonly trapped species, Mastomys natalensis and Tatera leucogaster.
Comparative and functional morphology of the middle ear in Zambezian mole-rats (Coetomys – Cryptomys, Bathyergidae)
(Belg. J. Zool, 2005-12) Leirs, Herwig; Makundi, Rhodes H.; Davis, Stephen; Lange, Simone; Burda, Hynek; Assogbadjo, A.E.; Codjia, J.T.C.; Sinsin, B.; Ekue, M.R.M.; Mensah, G.A.; Mgode, G.F.; Mhamphi, G.A.; Katakweba, A. W.; Paemelaere, E; Willekens, N.; Leirs, H.; Machang’u, R.S.; Hartskeerl, R.A.
Within the family Bathyergidae, the genus Coetomys (Cryptomys) is the most speciose. However, an unambiguous morphological or morphometrical species diagnosis has not been feasible to date. The middle ear structures involved in sound transmission were examined and measured in six species of Zambezian mole-rats of varying body sizes : Coetomys amatus, C. anselli, C. darlingi, C. kafuensis, C. mechowi and C. whytei. Compari- sons revealed many differences in the shape of the middle ear ossicles allowing species differentiation. Bullar vol- ume, eardrum area and cross-sectional area of the bony meatus were positively correlated with body size (as repre- sented by condylo-basal length) whereas the size of middle ear ossicles was rather independent of body size. Middle ears shared typical features with those found in low-frequency hearing mammals. Contrary to the findings in heter- omyids and the Spalax ehrenbergi species complex, within the genus Coetomys, those species occupying more mesic habitats had more efficient tympano-ossicular systems (suggesting more sensitive hearing) than species from drier habitats.
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.
Dietary differences of the multimammate mouse, Mastomys natalensis (Smith, 1834), across different habitats and seasons in Tanzania and Swaziland
(CSIRO PUBLISHING, 2011-11) Mulungu, Loth S.; Mahlaba, Themb’alilahlwa A.; Massawe, Apia W.; Kennis, Jan; Crauwels, Dieter; Eiseb, Seth; Monadjem, Ara; Makundi, Rhodes H.; Katakweba, Abdul A. S.; Leirs, Herwig; Belmain, Steven R.
eastern Africa where it can cause significant crop losses. Mastomys natalensis is known to consume a variety of food in response to the availability of food items. However, it is currently unknown whether maize crop growth stages affect the spatio-temporal diet of this species. Aims. We examined the foods consumed by M. natalensis in different habitats and seasons in central Tanzania and Swaziland. Methods. Diet was investigated in Tanzania in four different habitats (woodland, vegetable gardens, maize fields and fallow land) during different maize crop growth stages between March 2008 and February 2009. In Swaziland, this was conducted in three habitats (fallow land, cultivated fields and pristine land) during three crop growth stages (pre-planting, vegetative stage and post-harvest) between March 2008 and April 2009. Micro-histological examination of undigested fragments from the stomachs of trapped animals was made whereby the preserved stomach content was placed in a Petri dish and sorted using a 25 or 50 magnification binocular stereoscope. Stomach contents were identified as: grain and/or seeds (both grasses and maize), plant material (roots, stems and leaves), invertebrates, pods of seeds, fruits (vegetable fruit such as tomato), animal hairs and unidentified matter. If necessary, a lugol solution was used to determine the presence of starch for maize and grass seeds or grains. Key results. In both countries, grain predominated in the diet of M. natalensis. Statistical analyses showed that there were no differences due to seasons or habitats. Therefore, the percentage volume and relative importance were the same across habitats and seasons in both countries. Conclusions. Our findings highlight clearly that M. natalensis is a generalist species feeding on available resources depending on the season and the habitat. Its preference for grain may account for its abundance in maize plantations and confirms it as one of the major pests in crop plantations, especially grain. Implications. This information offers a useful tool for determining the pest status in different habitats and/or seasons. The findings of this study have implications for agriculture and conservation.
Differences in diet between two rodent species, Mastomys natalensis and Gerbilliscus vicinus, in fallow land habitats in central Tanzania
(2011-10) Mulungu, Loth S.; Massawe, Apia W.; Kennis, Jan; Crauwels, Dieter; Eiseb, Seth; Mahlaba, Themb’alilahlwa A.; Monadjem, Ara; Makundi, Rhodes H.; Katakweba, Abdul A. S.; Leirs, Herwig; Belmain, Steven R.
Differences in the ecological niche requirements among rodent species competing in the same habitat may result from differences in the use of one to three resources: space, time and food or some combination of these. Alternatively, differences in resource use utilization among animal species may simply reflect availability of food, and when food is limited, different animal species compete. In this study, the diet of two rodent pest species, Mastomys natalensis and Gerbilliscus vicinus, coexisting in fallow land in central Tanzania were studied to assess the degree of diet differentiation among them. Dietary niche breadth of G. vicinus was greater than that of M. natalensis in all stages of the maize cropping seasons. The rodent species studied overlapped considerably in the food items consumed ranging from niche overlap (Ojk) of 0.77–0.89. Grains/seeds featured high in the diet of M. natalensis while plant material occurrence was high in G. vicinus. These two food categories may have contributed to differences in diet partitioning, which may, in turn, facilitate their coexistence in fallow land.
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.
Does exploratory behavior or activity in a wild mouse explain susceptibility to virus infection?
(Oxford university press., 2017-09) Makundi, Rhodes H.; Massawe, Apia W; Leirs, Herwig; Hughes, Nelika K; Broecke, Bram V; Borremans, Benny; Mariën, Joachim
Exploration and activity are often described as trade-offs between the fitness benefits of gathering information and resources, and the potential costs of increasing exposure to predators and para- sites. More exploratory individuals are predicted to have higher rates of parasitism, but this relationship has rarely been examined for virus infections in wild populations. Here, we used the multimammate mouse Mastomys natalensis to investigate the relationship between exploration, activity, and infection with Morogoro virus (MORV). We characterized individual exploratory behav- ior (open field and novel object tests) and activity (trap diversity), and quantified the relationship between these traits and infection status using linear regression. We found that M. natalensis expresses consistent individual differences, or personality types, in exploratory behavior (repeat- ability of 0.30, 95% CI: 0.21–0.36). In addition, we found a significant contrasting effect of age on ex- ploration and activity where juveniles display higher exploration levels than adults, but lower field- activity. There was however no statistical evidence for a behavioral syndrome between these 2 traits. Contrary to our expectations, we found no correlation between MORV infection status and exploratory behavior or activity, which suggests that these behaviors may not increase exposure probability to MORV infection. This would further imply that variation in viral infection between individuals is not affected by between-individual variation in exploration and activity.
Effect of land preparation methods on spatial distribution of rodents in crop fields
(Australian Centre for International Agricultural Research, 2003) Massawe, Apia W.; Leirs, Herwig; Rwamugira, W. P.; Makundi, Rhodes H.
A mark–capture–release (CMR) study was carried out in Morogoro, Tanzania, from April 1999 to August 2000 to investigate the effect of slashing and burning versus tractor ploughing on the population of rodents in agricultural fields. We found that the spatial distribution of individuals was significantly affected by the land preparation method. The coefficient of dispersion values (based on variance-to-mean ratio calculations) indicated that more animals clustered around the edges in tractor-ploughed fields whereas in the slashed-and-burnt fields, animals were randomly distributed. Before land preparation, animals were randomly distributed everywhere. This suggests that the slashing-and-burning practice does not affect the rodent population distribution in crop fields while tractor ploughing does affect rodents, probably by reducing cover and food availability or even by killing some individuals. Yet, it seems useful as a management tool when it is practised over a large area and if the surrounding fallow lands, which act as donor habitat, are cleared.
The effect of soil physical properties and soil microclimate on rodent burrows’ abundance and their characteristics in Western Usambara Mountains, Tanzania
(ournal of Agriculture and Ecology Research International, 2014-12-16) Meliyo, Joel, L.; Brabers, Leon; Massawe, Boniface H. J.; Msanya, B. M.; Kimaro, D. N.; Mulungu, L. S.; Kihupi, N. I.; Deckers, Jozef, A.; Gulinck, Hubert; Leirs, Herwig
The present study was carried out between September 2009 and June 2013 in Western Usambara Mountains plague focus with the aim of establishing the influence of selected soil physical properties and soil microclimate on rodent burrows’ abundance, portal orientation and use. Two landscapes with high and medium plague frequencies in Lokome and Lukozi villages were studied. In the two landscapes data were collected from 117 and 200 observation sites respectively, using 100 m x 200 m quadrats. At each quadrat crossing, a sample quadrat of 20 m x 20 m was demarcated for scanning rodent burrows whereby burrows encountered were counted and their portal orientation and burrow use described. Within each sample quadrat, selected soil physical properties including thickness of the soil genetic horizons and soil dry consistence were determined. Soil samples were collected from each horizon for laboratory texture analysis. Temperature (surface and subsurface to a depth 10 cm) and relative humidity at a depth of 10 and 30 cm were collected using infrared, thermo-couple thermometers and i-Buttons. Descriptive statistics, ANOVA and logistic regression were used to analyse the data by R-software. There were significant (P=.0001) differences between the two landscapes regarding topsoil depth, infrared temperature, relative humidity and rodent burrows’ abundance. In the high plague frequency landscape there was a significant influence (P=.05) of topsoil horizon thickness on rodent burrows’ abundance and use. Results also indicate that soil temperature to a depth of 10 cm was significantly (P=.05) correlated with rodent burrow use. Likewise, in the medium plague frequency landscape, soil physical properties and soil microclimate significantly (P=.0001) discouraged rodent burrowing. It was concluded that soil physical and soil microclimate encouraged and discouraged burrowing in the high and the medium plague frequency landscapes, respectively. The landscape with high rodent burrows’ abundance corresponded with high plague frequency records.
Effects of forest disturbance on the fitness of an endemic rodent in a biodiversity hotspot
(Wiley, 2021) Ademola, Olaoluwa John; Broecke, Bram Vanden; Leirs, Herwig; Mulungu, Loth S.; Massawe, Apia W.; Makundi, Rhodes H.
Praomys delectorum occurs abundantly in both disturbed and intact forests in the Ukaguru Mountains within the Eastern Arc Mountains (EAM), Morogoro, Tanzania. While previous studies have reported that anthropogenic disturbances such as grazing, wood cutting, and harvesting have a positive effect on the population density of P. delectorum, the impact of habitat disturbance on its demographic traits is still unknown. We performed a capture–mark–recapture study in both disturbed and intact forests from June 2018 to February 2020 in order to investigate the effects of habitat disturbance on abundance and two demographic traits: survival and maturation of P. delectorum in the Ukaguru Mountains. We found no variation in abundance or maturation between intact and disturbed forests, but habitat type did affect survival. However, this effect was sex-dependent since female survival was higher in disturbed forests, while male survival remained similar across the two forest types potentially due to differences in predation pressure or food availability between the two habitats. Continuous demographic monitoring of P. delectorum in EAM is necessary given that the increasing human population surrounding the landscape is lead- ing to higher deforestation rates and expansion of the pine plantation in the forest reserve.
Evaluation of thiram and cinnamamide for protection of maize seeds against multimammate mice, Mastomys natalensis, in Tanzania
(2005) Ngowo, Victor H.; Mulungu, Loth; Lodal, Jens; Makundi, Rhodes H.; Massawe, Apia W.; Leirs, Herwig
Farmers in Tanzania consider rodents to be the major vertebrate pest of maize, especially at planting and seedling stages and annual losses are high. We evaluated the potential of two seed-dressing compounds, thiram and cinnamamide, as rodent repellents to protect maize against damage by multimammate rats, Mastomys natalen- sis. In laboratory tests, the two compounds showed a strong repellent effect against M. natalensis and thus the potential to protect maize seeds. The two compounds were evaluated in maize fields using Randomized Complete Block Design (RCBD) with three replications. The results show that these repellents are effective for protecting maize seeds against multimammate rats in the field, but in locations with high population of Tatera leucogaster, seedlings are still damaged after emergence. Therefore, in such locations, other control measures, including applica- tion of rodenticides just before seedling emergence may be necessary.
Farmers’ perspectives of rodent damage and management from the highlands of Tigray, Northern Ethiopian
(Elsevier, 2010-12-10) Yonas, Meheretu; Welegerima, Kiros; Deckers, Seppe; Raes, Dirk; Makundi, Rhodes; Leirs, Herwig
A farmers’ knowledge, attitude and practice (KAP) survey was conducted in the highlands of Tigray, northern Ethiopia, to better understand rodent damage and rodent management from the farmers’ perspective. Farmers (n 1⁄4 191) from Dogu’a Temben district, were interviewed using a semi-structured questionnaire. The large majority of the farmers stated that rodents are the main pests in crop fields (92.1%) and storage (88.5%). The farmers (64.2%) reported they experienced 100–500 kg ha 1 damage in crop fields, which is equivalent to 8.9–44.7% loss in annual production. There was some overlap between the most common crops grown in the highlands and the most common crops susceptible to rodent attack. Farmers identified barley as the crop most susceptible to rodent attack (76.4%) and the booting stage as the crop developmental stage with the highest rodent abundance and damage. Rodenticide application was the most commonly practiced management strategy in crop fields (51.8%); in storage, farmers mainly keep domestic cats around granaries (80.6%). We recommend a reduction in reliance on chemical rodenticide in crop fields and a shift to a more sustainable rodent management approach to reduce rodent numbers and damage.
Farmer’s perceptions of rodents as crop pests : Knowl- edge, attitudes and practices in rodent pest management in Tanzania and Ethiopia
(Belg. J. Zool, 2005-12) Makundi, Rhodes H.; Bekele, Afework; Leirs, Herwig; Massawe, Apia W.; Rwamugira, Winnie; Mulungu, Loth S.
A study was conducted using a structured questionnaire to obtain information about the nature and extent of rodent damage to crops, farmer’s perceptions of crop pests and their knowledge, attitudes and practices to their management in Tanzania and Ethiopia. The study was carried out in five localities (Makuyu -Central Tanzania; Chunya-Southwest Tanzania; Ziway and Adami Tulu (south of Addis Ababa) and Gumer/Limmo-South-west of Addis Ababa, both in Central Ethiopia). In Tanzania, maize is the major crop, both for food and sale. Other crops are sorghum, rice, simsim, groundnuts and millet. In Central Ethiopia, farmers grow maize, sorghum, teff, beans, barley, wheat, potatoes and enset. The study showed that farmers in Tanzania and Ethiopia are well aware of rodent problems and considered them to be number one pest. Rodent problems are regular and maize is the most affected crop in Tanzania. In Ethiopia, maize, enset and potatoes are the most affected crops. Maize in Ethiopia and Tanzania is susceptible to rodent damage, most seriously at planting and seedling stage. Although different rodent control techniques are practiced in Tanzania, farmers prefer using rodenticides (68.7%) to other strategies. In Ethiopia, trap- ping, hunting and rodenticides are the most practised techniques for rodent control. Farmer’s attempts to control rodents in both countries are based on economic reasons and generally, rodent control is not undertaken when there are no crops in the fields. Farmers are responsible for rodent control activities in their individual fields. The study shows that farmers in Tanzania and Ethiopia are concerned with rodent infestation and are also aware of the critical growth stage when the crops are most susceptible. A lack of multiple rodent management methods and inadequate knowledge of appropriate and sustainable techniques appeared to be the main reasons for the over dependence on rodenticides, particularly in Tanzania. Therefore, this suggests that farmers require a strong extension input to man- age rodent problems
First detection of Mycobacteria in African rodents and insectivores, using stratified pool screening
(American Society for Microbiology, 2008) Durnez, Lies; Eddyani, Miriam; Mgode, Georgies F.; Katakweba, Abdul; Katholi, Charles R.; Machang’u, Robert R.; Kazwala, Rudovik R.; Portaels, Franc¸oise; Leirs, Herwig
With the rising number of patients with human immunodeficiency virus (HIV)/AIDS in developing countries, the control of mycobacteria is of growing importance. Previous studies have shown that rodents and insectivores are carriers of mycobacteria. However, it is not clear how widespread mycobacteria are in these animals and what their role is in spreading them. Therefore, the prevalence of mycobacteria in rodents and insectivores was studied in and around Morogoro, Tanzania. Live rodents were trapped, with three types of live traps, in three habitats. Pieces of organs were pooled per habitat, species, and organ type (stratified pooling); these sample pools were examined for the presence of mycobacteria by PCR, microscopy, and culture methods. The mycobacterial isolates were identified using phenotypic techniques and sequencing. In total, 708 small mammals were collected, 31 of which were shrews. By pool prevalence estimation, 2.65% of the animals were carriers of mycobacteria, with a higher prevalence in the urban areas and in Cricetomys gambianus and the insectivore Crocidura hirta. Nontuberculous mycobacteria (Mycobacterium chimaera, M. intracellulare, M. arupense, M. parascrofulaceum, and Mycobacterium spp.) were isolated from C. gambianus, Mastomys natalensis, and C. hirta. This study is the first to report findings of mycobacteria in African rodents and insectivores and the first in mycobacterial ecology to estimate the prevalence of mycobacteria after stratified pool screening. The fact that small mammals in urban areas carry more mycobacteria than those in the fields and that potentially pathogenic mycobacteria were isolated identifies a risk for other animals and humans, especially HIV/AIDS patients, that have a weakened immune system.
"Gairovirus,anovelarena virusof the widespread Mastomys natalensis: genetically divergent,but ecologically similar to Lassa and Morogoro viruses
(ElsevierInc, 2015) Gryseels, Sophie; Rieger, Toni; Oestereich, Lisa; Cuypers, Bart; Borremans, Benny; Makundi, Rhodes; Leirs, Herwig; Günther, Stephan; Goüy de Bellocq, Joëlle
Despite itsnearpan-Africanrange,theNatalmultimammatemouse, Mastomysnatalensis, carriesthe human pathogenLassavirusonlyinWestAfrica,whiletheseeminglynon-pathogenicarenaviruses Mopeia, Morogoro,andLunahavebeendetectedinthissemi-commensalrodentinMozambique/ Zimbabwe,TanzaniaandZambia,respectively.Here,wedescribeanovelarenavirusin M. natalensis from Gairo districtofcentralTanzania,forwhichweproposethename “Gairo virus”. Surprisingly,thevirusis not closelyrelatedwithMorogorovirusthatinfects M. natalensis only 90kmsouthofGairo,butclusters phylogeneticallywithMobala-likevirusesthatinfectnon-M. natalensis host speciesinCentralAfrican RepublicandEthiopia.Despitetheevolutionarydistance,Gairovirussharesbasicecologicalfeatures with theother M. natalensis-borne virusesLassaandMorogoro.Ourdatashowthat M. natalensis, carrying distantlyrelatedviruseseveninthesamegeographicalarea,isapotentreservoirhostfora varietyofarenaviruses.
Influence of land preparation methods and vegetation cover on population abundance of Mastomys natalensis in Morogoro, Tanzania
(2005-12) Massawe, Apia W.; RWAMUGIRA, Winifrida; Leirs, Herwig; Makundi, Rhodes H.; Mulungu, Loth
A Capture-Mark-Release study was carried out in Morogoro, Tanzania, from April 1999 to April 2001 to investigate the effects of land preparation methods and cropping systems on population abundance of Mastomys natalensis in crop fields. Two land preparation methods (tractor ploughing; slash and burning) and two cropping systems (mono-cropping with maize; inter-cropping with maize and beans) were included in the study. The experi- mental design was a Complete Randomized Design with 2x2 factors, with two replicates. In slash and burn fields, rodent population abundance and distribution were strongly influenced by vegetation cover regardless of the type of cropping system. Higher rodent population peaks occurred in dense vegetation cover in slash and burn relative to tractor ploughed fields. In contrast, there were no obvious associations between vegetation cover and population abundance in the tractor ploughed fields, particularly in the mono-cropping system. A negative correlation between vegetation cover and population abundance of M. natalensis was obtained in fallow land surrounding the crop fields (r = -0.63; p ≤ 0.05). The results show that the effect of vegetation cover on population abundance of M natalensis in crop fields is strongly influenced by the type of land preparation methods. Tractor ploughing and clearance of fal- low land surrounding crop fields could be a useful method to reduce the invasion of crops by M. natalensis.
Landform and surface attributes for prediction of rodent burrows in the Western Usambara Mountains, Tanzania
(Tanzania Journal of Health Research, 2014-07) Meliyo, Joel, L.; Massawe, Boniface H. J.; Msanya, B. M.; Kimaro, D. N.; Hieronimo, Proches; Mulungu, Loth S.; Kihupi, N. I.; Deckers, Jozef, A.; Gulinck, Hubert; Leirs, Herwig
Previous studies suggest that rodent burrows, a proxy for rodent population are important for predicting plague risk areas. However, studies that link landform, surface attributes and rodent burrows in the Western Usambara Mountains in Tanzania are scanty. Therefore, this study was conducted in plague endemic area of the Western Usambara Mountains in northern, Tanzania, to explore the relationship between rodent burrows, and landform and surface attributes. The study was carried out in three areas corresponding to high (Lokome), medium (Lukozi) and low (Mwangoi) frequency of reported plague cases. Data were collected from 117, 200 and 170 observation sites for Lokome, Lukozi and Mwangoi, respectively using 100 m x 200 m quadrats. Remote sensing and field surveys were used to collect data on landform and surface attributes. Rodent burrows were surveyed and quantified by counting the number of burrows in 20m x 20m grids demarcated on the main 100m x 200m quadrats. The collected data were analysed in R software using boosted regression trees (BRT) technique. Rodent burrows were found at an elevation of above 1600m in the high and medium plague frequency landscapes. No burrows were found in the low plague frequency landscape situated below 1500m. BRT analysis shows a significant relationship between landform characteristics and rodent burrows in both high and medium plague frequency landscapes. Overall, elevation and hillshade are the most important determinants of rodent burrow distribution in the studied landscapes. It is concluded that in high altitudes, specific landform attributes (hill-shade, slope, elevation) and vegetation cover- favour rodent burrowing.