Institute of Pest Management
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Item Ability of Cricetomys rats to detect Mycobacterium tuberculosis and discriminate it from other microorganisms(2011-11-26) Mgode, G.F; Weetjens, B; Cox, C; Jubitana, M; Machang’u, R; Lazar, D; Weiner, J; Geertruyden, J.P; Kaufmann, STrained African giant pouched rats (Cricetomys gambianus) have potential for diagnosis of tuberculosis (TB). These rats target volatile compounds of Mycobacterium tuberculosis (Mtb) that cause TB. Mtb and nontuberculous mycobacteria (NTM) species are related to Nocardia and Rhodococcus spp., which are also acid-fast bacilli and can be misdiagnosed as Mtb in smear microscopy. Diagnostic performance of C. gambianus on in vitro-cultured mycobacterial and related pulmonary microbes is unknown. This study reports on the response of TB detection rats to cultures of reference Mtb, clinical Mtb, NTM, Nocardia; Rhodococcus; Streptomyces; Bacillus; and yeasts. Trained rats significantly discriminated Mtb from other microbes (p < 0.008, Fisher’s exact test). Detection of Mtb cultures was age-related, with exponential and early stationary phase detected more frequently than early log phase and late stationary phase (p < 0.001, Fisher’s test) (sensitivity ¼ 83.33%, specificity ¼ 94.4%, accuracy ¼ 94%). The detection of naturally TB-infected sputum exceeded that of negative sputum mixed with Mtb, indicating that C. gambianus are conditioned to detect odours of TB-positive sputum better than spiked sputum. Although further studies on volatiles from detectable growth phases of Mtb are vital for identification of Mtb-specific volatiles detected by rats, our study underline the potential of C. gambianus for TB diagnosis.Item Accuracy of giant African pouched rats for diagnosing tuberculosis: comparison with culture and Xpert W MTB/RIF(Researchgate, 2017) Mulder, C.; Mgode, G. F.; Ellis, H.; Valverde, E.; Beyene, N.; Cox, C.; Reid, S. E.; Van’t Hoog, A. H.; Edwards, T. L.S E T T I N G : Enhanced tuberculosis (TB) case finding using detection rats in Tanzania. O B J E C T I V E S : To assess the diagnostic accuracy of detection rats compared with culture and Xpert w MTB/ RIF, and to compare enhanced case-finding algorithms using rats in smear-negative presumptive TB patients. D E S I G N : A fully paired diagnostic accuracy study in which sputum of new adult presumptive TB patients in Tanzania was tested using smear microscopy, 11 detection rats, culture and Xpert. R E S U LT S : Of 771 eligible participants, 345 (45%) were culture-positive for Mycobacterium tuberculosis, and 264 (34%) were human immunodeficiency virus (HIV) positive. The sensitivity of the detection rats was up to 75.1% (95%CI 70.1–79.5) when compared with cul- ture, and up to 81.8% (95%CI 76.0–86.5) when compared with Xpert, which was statistically signifi- cantly higher than the sensitivity of smear microscopy. Corresponding specificity was 40.6% (95%CI 35.9– 45.5) compared with culture. The accuracy of rat detection was independent of HIV status. Using rats for triage, followed by Xpert, would result in a statistically higher yield than rats followed by light- emitting diode fluorescence microscopy, whereas the number of false-positives would be significantly lower than when using Xpert alone. C O N C L U S I O N : Although detection rats did not meet the accuracy criteria as standalone diagnostic or triage testing for presumptive TB, they have additive value as a triage test for enhanced case finding among smear- negative TB patients if more advanced diagnostics are not availableItem Active tuberculosis detection by pouched rats in 2014: more than 2,000 new patients found in two countries(2016 Society for the Experimental Analysis of Behavior, 2016) Poling, A.; Beyene, N.; Valverde, E.; Mulder, C.; Cox, C.; Mgode, G.; Edwards, T. L.Tuberculosis (TB) is a major problem in poor countries because sensitive diagnostic tools are unavail- able. In 2014, our pouched rats evaluated sputum from 21,600 Tanzanians and 9,048 Mozambicans whose sputum had previously been evaluated by microscopy, the standard diagnostic for TB. Evalua- tion by the rats revealed 1,412 new patients with active TB in Tanzania and 645 new patients in Mozambique, increases of 39% and 53%, respectively, when compared to detections by microscopy alone. These results provide further support for the applied use of scent-detecting rats.Item African centre of excellence for innovative rodent pest management and biosensor technology development (ACE IRPM and BTD- Rat-Tech)(2016-10) Makundi, R. H; Massawe, A.WRodents are some of the most serious mammalian pests the world over. However, their economic and social impact is not quantified in Sub-Saharan Africa. Moreover, while some of the zoonotic diseases attributed to rodents such as Lassa fever and bubonic plague are endemic in rural Africa, occasionally leading to serious outbreaks, more often than not, rodent-borne diseases are not recognized, and hence are inadequately managed. The African Centre of Excellence (ACE) in Innovative Rodent Pest Management and Biosensor Technology Development (IRPM and BTD) will enhance scientific knowledge, Technology and Innovation (STI) on Rodent Pest Management in Africa. The IRPM and BTD activities will incorporate biosensor technology using trained rats for land mine detection and support their operational deployment to complement existing technologies to free mine afflicted lands in Africa and elsewhere and release these for safe use by humans (settlement, agriculture, mining, livestock, etc.). Novel diagnostic approaches are a key component to tackling Tuberculosis epidemic, yet in resource-limited settings in Africa, the latest advanced diagnostic technologies are lacking. Trained rats are efficient and reliable TB diagnostic biosensor technology. The ACE for IRPM and BTD will build capacity through training at the MSc and PhD levels in rodent taxonomy, ecology, innovative STI in rodent management and biosensor technology. IRPM and BTD will establish basic and applied research programs for African scientists to pursue high-impact projects in rodent management, understanding the impact of zoonotic diseases on communities and their mitigation, and how best to use biosensor technology for detecting landmines and diagnosis of diseases. A minimum of 60 Master of Science and 32 PhD students will be trained and faculty exchange between regional higher education institutions will be supported. Short courses will be conducted focusing on dissemination of sustainable STI solutions to rodent problems in Africa. Research will be focused to solve regional rodent problems that impact on rural communities in Africa.Item African pouched rats for the detection of pulmonary tuberculosis in sputum samples(2009) Weetjens, B.J; Mgode, G.F.; Machang’u, R.S; Kazwala, R; Mfi nanga, G; Lwilla, F; Cox, C; Jubitana, M; Kanyagha, H; Mtandu, R; Kahwa, A; Mwessongo, J; Makingi, G; Mfaume, S; Steenberge, J.V; Beyene, N.W; Billet, M; Verhagen, RSETTING: Resource-limited settings in sub-Saharan African countries. OBJECTIVE: To utilise African giant pouched rats (Cricetomys gambianus) for the diagnosis of tuberculosis (TB) in human sputum. DESIGN: A specially designed cage with 10 sniffi ng holes and cassette-carrier was used. The sputum samples were put in the sample cassette, containing 10 samples in line, placed under matching sniffi ng holes. Rats were trained to sniff each consecutive sample, and indicate TB positives by fi xing their nose for 5 seconds at the sniffi ng hole. This behaviour was maintained by food reinforcement upon correct indications. A total of 3416 samples were used. RESULTS: Of the 20 trained rats, 18 were able to discriminate positive from negative sputum samples, with average daily sensitivities ranging from 72% to 100%, and average daily false-positives ranging from 0.7% to 8.1%. The use of multiple rats signifi cantly increased sensitivity and negative predictive value. CONCLUSION: Utilising trained sniffer rats for TB detection is a potentially faster screening method and is at least as sensitive as smear microscopy. This method could therefore be suitable for active case fi nding, especially where large numbers of samples are to be analysed in resource-limited settings, to complement existing diagnostic techniques.Item Anopheline and culicine mosquitoes are not repelled by surfaces treated with the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana(Parasites & Vectors, 2010) Mnyone, L. L.; Koenraadt, C. J. M.; Lyimo, I. N.; Mpingwa, M. W.; Takken, W.; Russell, T. L.Background: Entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, are promising bio-pesticides for application against adult malaria mosquito vectors. An understanding of the behavioural responses of mosquitoes towards these fungi is necessary to guide development of fungi beyond the ‘proof of concept’ stage and to design suitable intervention tools. Methods: Here we tested whether oil-formulations of the two fungi could be detected and avoided by adult Anopheles gambiae s.s., Anopheles arabiensis and Culex quinquefasciatus. The bioassays used a glass chamber divided into three compartments (each 250 × 250 × 250 mm): release, middle and stimulus compartments. Netting with or without fungus was fitted in front of the stimulus compartment. Mosquitoes were released and the proportion that entered the stimulus compartment was determined and compared between treatments. Treatments were untreated netting (control 1), netting with mineral oil (control 2) and fungal conidia formulated in mineral oil evaluated at three different dosages (2 × 1010, 4 × 1010 and 8 × 1010 conidia m-2). Results: Neither fungal strain was repellent as the mean proportion of mosquitoes collected in the stimulus compartment did not differ between experiments with surfaces treated with and without fungus regardless of the fungal isolate and mosquito species tested. Conclusion: Our results indicate that mineral-oil formulations of M. anisopliae and B. bassiana were not repellent against the mosquito species tested. Therefore, both fungi are suitable candidates for the further development of tools that aim to control host-seeking or resting mosquitoes using entomopathogenic fungi.Item Antibiotic susceptibilities of indicator bacteria Escherichia coli and Enterococci spp. isolated from ducks in Morogoro municipality, Tanzania(BMC Research Notes, 2018) Kissinga, H. D.; Mwombeki, F.; Said, K.; Katakweba, A. A. S.; Nonga, H. E.; Muhairwa, A. P.To estimate the prevalence of antibiotic resistance in indicator bacteria Escherichia coli and Enterococci isolated from duck faeces in Morogoro Municipality, Tanzania. Results: Escherichia coli and Enterococcus isolation rates from ducks faeces were 91 and 100% respectively. The prevalence of antibiotic resistance of E. coli and Enterococcus was 70.3 and 42%, respectively. E. coli resistant to four antibiotics were 28 (30.8%) and showed high resistance to ampicillin (81.3), tetracycline (75.8) and trimethoprim–sulphamethoxine (62.3). Multiple antibiotic resistance of Enterococcus were more than 65%. High resistance rates shown by Enterococcus were observed in rifampin (62%), ampicillin (62%) and tetracycline (42%). Almost all farmers (92.3%) left their ducks to scavenge for food around their houses. Antibiotics used in animal treatments were oxytetracyclines, sulfonamides, penicillin dihydrostreptomycin while in humans were tetracycline, ampicillin, and amoxicillin.Item Antifungal effect of a local bacillus subtilis, isolate TM07, on Fusarium oxysporum f.sp. Lycopersici in Morogoro, Tanzania(Tanzania Journal of Agricultural Sciences, 2021) Machang’u, R; Maerere, A.; Mwinuka, B; Nashon, J; Makingi, GFusarium oxyporum f.sp. lycopersici causes tomato wilt, a severe disease that leads to extensive yield and quality loss of tomatoes in Tanzania. Management of Fusarium infection is particularly challenging given the health and environmental concerns over continued use of chemical pesticides on horticultural food crops. However, there is an increasing focus towards the use of biocontrol agents to combat phytopathogens worldwide. In this study, bacterial isolates from tomato rhizosphere were screened for their antagonistic activity in vitro on F. oxysporum. Based on its superior effectiveness, one isolate, designated TM07, was selected and characterized as Bacillus subtilis by morphological, biochemical and molecular procedures. On potato dextrose agar (PDA) the isolate showed an appreciable degree of radial growth inhibition (RGI) of 40.5% of the Fusarium, compared to control (55.9%). Further investigations are recommended to elucidate on the mechanism behind the inhibitory effect of isolate TM07. In vivo studies are also recommended to assess the possibility of applying the B. subtilis, isolate TM07, as a local biocontrol agent of Fusarium wilt of tomato and other susceptible crops.Item Antimicrobial resistance in faecal samples from buffalo, wildebeest and zebra grazing together with and without cattle in Tanzania(Journal of Applied Microbiology, 2014-11-28) Katakweba, A. A. S.; Møller, K. S.; Muumba, J.; Muhairwa, A. P.; Damborg, P.; Rosenkrantz, J. T.; Minga, U. M.; Mtambo, M. M. A.; Olsen, J. E.Aim: The aim of this study was to determine whether the practice of co-grazing with cattle and wild life constitutes a risk of transmission of antibiotic resistant bacteria to wild ungulates. Methods and Results: Faecal samples were collected from buffalo (n = 35), wildebeest (n = 40), zebra (n = 40) and cattle (N = 20) from Mikumi National Park, Tanzania (MNP), where cattle is prohibited and from Ngorongoro Conservation Area (NCA) where co-grazing is practiced. The number of coliforms and enterococci resistant to selected antibiotics was determined. Wild life generally harboured higher number of resistant Escherichia coli and Enterococci than cattle, but with no general influence in wild life of co-grazing with cattle. Vancomycin-resistant Enterococci were detected in wild life samples, and E. coli resistant to cefotaxime and enrofloxacin were observed among isolates from all wild life, but not from cattle. Culture independent estimates of the number of sulII gene copies obtained by qPCR did not differ between wild life from the two sample sites, while tetW was significantly higher in samples from MPN than from NCA. Conclusions: Antibiotic resistant bacteria were not more frequently found in ungulates grazing together with cattle than ungulates without this interaction. Significance and Impact of the Study: This study did not indicate that transmission of antibiotic resistant bacteria is a frequent event following co-grazing of wild life and cattle.Item APOPO’s tuberculosis research agenda: achievements, challenges and prospects(2012-04) Beyene, N; Mahoney, A; Cox, C; Weetjens, B; Making, G; Mgode, G; Durgin, A; Kuipers, D; Jubitana, M; Egwaga, S; Kamala, D; Lwila, F; Mfinanga, S; Kahwa, A; Machangu, R; Kazwala, R; Reither, K; Kaufmann, S; Poling, AThis article describes Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling (APOPO) recent use of specially trained African giant pouched rats as detectors of pulmonary tuberculosis in people living in Tanzania. It summarizes the achievements and challenges encountered over the years and outlines future prospects. Since 2008, second-line screening by the rats has identified more than 2000 tuberculosis-positive patients who were missed by microscopy at Direct Observation of Treatment – Short Course centres in Tanzania. Moreover, data that are reviewed herein have been collected with respect to the rats’ sensitivity and specificity in detecting tuberculosis. Findings strongly suggest that scent-detecting rats offer a quick and practical tool for detecting pulmonary tuberculosis and within the year APOPO’s tuberculosis-detection project will be extended to Mozambique. As part of its local capacity building effort, APOPO hires and trains Tanzanians to play many important roles in its TB detection project and provides research and training opportunities for Tanzanian students.Item Application of a multidisciplinary approach to the systematics of Acomys (Rodentia: Muridae) from Northern Tanzania(2006-12) Mgode, G. F.The systematic status and geographic distribution of spiny mice of the genus Acomys I. Geoffroy, 1838 in Northern Tanzania is uncertain. This study assesses the systematic and geographic distribution of Acomys from Northern Tanzania using a multidisciplinary approach that includes molecular, cytogenetic, traditional and geometric morphometric analyses, and classical morphology of the same individuals. The molecular analysis was based on 1140 base pairs (bp) of the mitochondrial cytochrome b and 1297 bp of the nuclear interphotoreceptor retinoid binding protein (IRBP) gene sequences. These data were subjected to phylogenetic analyses using Maximum likelihood, Bayesian, Maximum parsimony, and Minimum evolution analyses. The cytogenetic analysis included G-banding of metaphase chromosomes. The morphometric analyses included univariate and multivariate analyses of traditional morphometric measurements of the cranium and mandible, and of geometric morphometric two-dimensional landmarks of the dorsal, ventral, and lateral views of the cranium, and lateral view of mandible that included thinplate spline (TPS) analysis. The classical morphology included examination of external, cranial and mandibular morphology. Results of all these multidisciplinary analyses were congruent and provide evidence for the occurrence of two sympatric species of Acomys in northern Tanzania, namely, the previously recorded A. wilsoni (2n = 62) and a newly recorded A. cf. percivali (2n = 58). These results that also represent the first reported mitochondrial cytochrome b and nuclear IRBP gene sequences and karyotype for A. cf. percivali, increases the number of species known to occur in Tanzania from four to five. However, the mitochondrial cytochrome b data that included GenBank sequences from the type locality in Kenya suggest that A. wilsoni may not be monophyletic. Ecologically, the two species seem to partition their niches with A. cf. percivali being found in well-covered habitats with thorn bushes, rocky and mountainous areas, and A. wilsoni being found in open semi-arid grasslands as well as in rice fields. The two species appear to be isolated by complex natural barriers formed by the Great East African Rift Valley whose geological features have generally been associated with active rodent speciation. However, the present results need further multidisciplinary investigation involving extensive sampling and examination of topotypical material.Item 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.hItem 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, HerwigInfectious 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.Item Arenavirus infection correlates with lower survival of its natural rodent host in a long-term capture-mark-recapture study(2018) Mariën, J.; Sluydts, V.; Borremans, B.; Gryseels, S.; Broecke, B. V.; Sabuni, C. A.; Katakweba, A. A. S.; Mulungu, L. S.; Günther, S.; de Bellocq, J. G.; Massawe, A. W.; Leirs, HBackground: Parasite evolution is hypothesized to select for levels of parasite virulence that maximise transmission success. When host population densities fluctuate, low levels of virulence with limited impact on the host are expected, as this should increase the likelihood of surviving periods of low host density. We examined the effects of Morogoro arenavirus on the survival and recapture probability of multimammate mice (Mastomys natalensis) using a seven-year capture-mark-recapture time series. Mastomys natalensis is the natural host of Morogoro virus and is known for its strong seasonal density fluctuations. Results: Antibody presence was negatively correlated with survival probability (effect size: 5–8% per month depending on season) but positively with recapture probability (effect size: 8%). Conclusions: The small negative correlation between host survival probability and antibody presence suggests that either the virus has a negative effect on host condition, or that hosts with lower survival probability are more likely to obtain Morogoro virus infection, for example due to particular behavioural or immunological traits. The latter hypothesis is supported by the positive correlation between antibody status and recapture probability which suggests that risky behaviour might increase the probability of becoming infected.Item Assessment of maize (zea mays l.) damage and yield loss due to rodents in the field(Sokoine University of Agriculture, 200) Mulungu, Loth SikweseAssessment of damage and yield Joss due to rodents was carried out in maize fields in Morogoro. Tanzania. The most abundant rodents in these fields were the multimammate rats. Mastomys nalalensis. Spatial distribution of damage in maize fields was random for experimental fields planted with maize, located between other maize fields owned by farmers. Four sampling techniques viz: non stratified systematic row sampling, non stratified systematic z-sampling. stratified random square sampling, and non stratified simple random sampling for estimation of maize damage and yield losses due to rodents were compared in terms of precision and accuracy, and time spent for damage and yield loss estimations. The actual rodent damage in 15 maize fields was determined by counting damaged and undamaged maize plants at seedling stage and the actual yield loss was calculated. The actual damage varied from 17.3% to 82% during the period of study. The results showed clearly that non-stratified systematic row sampling is the most robust technique for assessing maize damage and yield loss due to rodents. A standard curve for sampling using this technique is provided. The relationship between rodent density and maize damage at seedling was determined. The best model for the data was determined using Akaike Information Criterium. The best model for the relationship is Sigmoid (r - 0.74; n = 44; p = 0.001). Variations occurred between the observed and predicted line. Damage was low or high depending on the amount of rainfall after planting. Maize seed planting followed by heavy rainfall suffered lower damage than when rainfall was poor, due to inability by rodents to locate the planted seeds. Rodent damage and the resultant yield loss are positively correlated, but only in years with well distributed rainfall. Results from model simulations showed that it is more profitable to control rodents in the fields in February and November or February and October than any other month combinations. This calendar approach for rodent control seems to be most appropriate for the Tanzanian maize growers.Item Assessment of rodent damage to stored maize (Zea mays L.) on smallholder farms in Tanzania(Taylor & Francis, 2014) Mdangi, M.; Mulungu, Loth S.; Massawe, A.W.; Eiseb, S.J.; Tutjavi, V.; Kirsten, F.; Mahlaba, T.; Malebane, P.; Maltitz, E. von; Monadjem, A.; Dlamini, N.; Makundi, Rhodes H.This study examined rodent damage, loss and contamination in stored maize on smallholder farms in East Africa. Different, novel techniques for assessing rodent damage, namely open and closed storage structures (cribs and sacks), were employed in a treatment-control trial design replicated across different households and hamlets within the Berega community of Central Tanzania. Significant correlations were observed between the monthly rates of rodent-damaged maize seeds, maize weight loss and the number of rodent droppings. Significant differences in damage, loss and contamination occurred between different storage structures (open and closed cribs and sacks). The mean monthly rate of damage was 40.4%, 7.9%, 17.7% and 0% percent in open cribs, closed cribs, open sacks and closed sacks, respectively. Our results suggest that reducing rodent infestation through the use of improved storage structures could lead to major savings in the amount and quality of stored food available to households, thus increasing food security.Item The bioeconomics of controlling an African rodent pest species.(Cambridge University Press., 2006) Skonhoft, A.; Leirs, H.; Andreassen, H. P.; Mulungu, L. S.A.; Stenseth, N. C.The paper treats the economy of controlling an African pest rodent, the multimammate rat, causingmajor damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the costs are made up of the cost of poison plus the damage to maize production. We analyse how the present-value costs of maize production are affected by variousItem Breeding dynamics of rodent species inhabiting farm–fallow mosaic fields in Central Tanzania(2012-04) Massawe, A. W.; Makundi, R. H.; Mulungu, L. S.; Katakweba, A.; Shayo, T. N.The breeding dynamics of three species of rodents, Mastomys natalensis, Aethomys chrysophilus and Gerbilliscus vicina were investigated in a seasonal environment (wet versus dry) in Berega in the eastern parts of central Tanzania. Berega has a distinct unimodal rainfall pattern, with most rainfall from November to April/May. We hypothesized that breeding of rodents in central Tanzania would be confined to the wet season, when unlimited resources would be available for reproduction. We provide evidence of breeding discontinuity in the three species, showing that breeding was seasonally restricted to the wet season and early in the dry season. The observed discontinuity could largely be ascribed to variation in primary productivity between the wet and dry seasons. Reproductively active females were found in the population as early as November, a month into the rainy season, but when early rains occurred, some individuals were already breeding in October. Breeding was more intensive in the latter part of the wet season (March–May) and completely ceased during the dry season. For M. natalensis, survival was highest in the wet period and low in the dry season. The study provides knowledge on the breeding dynamics of rodents in central Tanzania, which can help farmers to take proactive rodent management decisions to prevent high rodent densities and reduce crop damage in the fields. Application of control measures by the community early in the season when populations of reproductive females is lowest will be most rewarding.Item Breeding dynamics of rodent species inhabiting farm–fallow mosaic fields in Central Tanzania(African Zoology, 2012-02) Massawe, Apia W.; Makundi, Rhodes H.; Mulungu, Loth S.; Katakweba, Abdul; Shayo, Teresia N.The breeding dynamics of three species of rodents, Mastomys natalensis, Aethomys chrysophilus and Gerbilliscus vicina were investigated in a seasonal environment (wet versus dry) in Berega in the eastern parts of central Tanzania. Berega has a distinct unimodal rainfall pattern, with most rainfall from November to April/May. We hypothesized that breeding of rodents in central Tanzania would be confined to the wet season, when unlimited resources would be available for reproduction. We provide evidence of breeding discontinuity in the three species, showing that breeding was seasonally restricted to the wet season and early in the dry season. The observed discontinuity could largely be ascribed to variation in primary productivity between the wet and dry seasons. Reproductively active females were found in the population as early as November, a month into the rainy season, but when early rains occurred, some individuals were already breeding in October. Breeding was more intensive in the latter part of the wet season (March–May) and completely ceased during the dry season. For M. natalensis, survival was highest in the wet period and low in the dry season. The study provides knowledge on the breeding dynamics of rodents in central Tanzania, which can help farmers to take proactive rodent management decisions to prevent high rodent densities and reduce crop damage in the fields. Application of control measures by the community early in the season when populations of reproductive females is lowest will be most rewarding.Item Breeding patterns of Arvicanthis neumanni in central Tanzania(Blackwell Publishing Ltd, Afr. J. Eco, 2007) Massawe, A. W.; Mrosso, F. P.; Makundi, Rhodes H.; Mulungu, Loth S.The breeding pattern of the grass rat, Arvicanthis neumanni, was investigated in central Tanzania in 2002 ⁄ 2003. Nine hundred and forty-seven animals were captured in three age groups: juveniles, sub adults and adults. These age groups were present in the population for an extended duration, but there was an increase in the number of sexually active individuals and juveniles 2–3 months after the onset of the rains (December 2002–May 2003). A peak in reproductive activity occurred between January and April. Litter size ranged between 5.58 ± 0.42 and 6.1 ± 0.26 in two study sites. There were no significant differences in the number of embryos implanted in the right and left horns of the uterus of pregnant females (t 22 = 0, P > 0.05 and t 36 = 1.68, P > 0.05, respec- tively). Sex ratio of A. neumanni was not skewed to either males or females. Breeding was seasonal and seemed to be associated with seasonal variations in primary productiv- ity, which relates to rainfall patterns.