Browsing by Author "Kilonzo, B.S"
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Item Food preferences of the multi-mammate mouse, Mastomys natalensis, in irrigated rice habitats in Tanzania(Taylor & Francis, 2014) Mulungu, L.S.; Mlyashimbi, E.C.M; Ngowo, V; Mdangi, M; Katakweba, A.S; Tesha, P; Mrosso, F.P; Mchomvu, M; Kilonzo, B.S; Belmain, S.R.We investigated the composition of the diet of the multi-mammate mouse, Mastomys natalensis, within irrigated rice and fallow field habitats at set time periods related to rice crop growth stages. In both habitats, vegetative plant material, i.e. leaves, stems and seeds, were the most abundant components of the rodent’s diet, while other food types (invertebrates, fruits) were observed only in low quantities. We conclude that vegetative plant material and seeds were the main types of food consumed not only due to their relatively higher abundance in the environments under study but also because of the highly specialised herbivorous/granivorous nature of the dominant rodent species, M. natalensis. Thus, the introduction and expansion of continuous rice-cropping using irrigation in Tanzania is likely to be severely constrained by the presence of M. natalensis. In our opinion, field hygiene, including the removal of alternative food resources and nesting sites for M. natalensis near cropping areas, may help to both lower rodent population numbers and reduce immigration potential. Nonchemical rodent control methods such as trap barrier systems developed for lowland irrigated rice in south-eastern Asia should, we argue, be evaluated for their effectiveness under African conditions.Item Impact of spatio-temporal simulations of rat damageon yield of rice (Oryza sativa L.) and implications forrodent pest management(Taylor & Francis, 2014-11-29) Mulungu, L.S; Lagwen, P.P; Mdang, M.E; Kilonzo, B.S; Belmain, S.RRodents often damage crops throughout the growing season, from germination to harvest, thus making it difficult to understand the cumulative effects of rodent damage for crops such as rice that are able to partially compensate for damage. Compensation can make it difficult to understand the impact of variable rodent damage in terms of when the damage occurs, its severity and thus when, whether and how rodent pests should be controlled. The compensatory responses of rice to simulated rat damage carried out at different growth stages and at different spatial levels of severity showed that higher yield was recorded during the wet season in comparison to the dry season. However, yield loss was observed during all cropping stages for all levels of simulated damage for wet and dry season crops, with significant compensation noted at the transplanting [14 days after sowing (DAS)] and vegetative (45 DAS) stages. Only damage at the maturity (110 DAS) stage resulted in significant reductions in rice crop yield. Seasonal differences suggest water availability was an important factor that perhaps enhanced rice production. The ability of rice to compensate for early rodent damage could potentially reduce a farmer's perception of damage. However, failing to control rodents at these earlier crop growth stages could lead to increased rodent populations at the time of maturity when compensatory effects are limited.Item Importance of intersectoral co-ordination in the control of communicable diseases, with special reference to plague in Tanzania(1994-07) Kilonzo, B.SHuman health, agriculture, including livestock, energy, education, wildlife, construction, forestry and trade sectors are inter-related and their co-ordination is an important pre-requisite for successful control of most communicable diseases including plague. Similar linkage between research, policy, training and extension activities in each sector are essential for any successful control strategy. Inadequate agricultural produce, inaccessibility of people to the available food and ignorance on proper preparation and usage of available food materials are responsible for malnutrition, and malnourished people are very vulnerable to disease. Irrigation schemes facilitate breeding of various disease vectors and transmission of some communicable diseases. Forests are ecologically favourable for ] some disease vectors and reservoirs for tsetse flies and rodents, while deforestation leads to soil erosion, lack of rainfall and consequently reduced productivity in agriculture which may result in poor nutrition of the population. Wildlife and livestock serve as reservoirs and/or carriers of various zoonoses including plague, trypanosomiasis and rabies. Lack of proper co-ordination of these sectors in communicable disease control programmes can result in serious and undesirable consequences. Indiscriminate killing of rodents in order to minimize food damage by these vermin forces their flea ectoparasites to seek alternative hosts, including man, a development which may result in transmission of plague from rodents to man. Similarly, avoidance of proper quarantine during plague epidemics, an undertaking which is usually aimed at maintaining economic and social links with places outside the affected focus, can result in the disease becoming widespread and consequently make any control strategies more difficult and expensive. It is generally concluded that inter and intrasectoral linkages are inevitable and close co-ordination between and within various sectors is essential for successful control of communicable diseases. Regular professional workshops involving researchers, extension officers and policy makers from all relevant sectors are recommendedItem Observations on the endemicity of plague in Karatu and Ngorongoro, northern Tanzania(2006) Kilonzo, B.S; Mbise, T.J; Mwalimu, D.C; Kindamba, L.Commensal and field rodents and wild small carnivores were live-trapped in five villages of Karatu district and one settlement in the Ngorongoro Conservation Area in Ngorongoro district in Tanzania. Blood samples were taken and serologically tested for plague, using the Blocking ELISA technique. Some domestic dogs and cats in the Karatu villages were aseptically bled and similarly tested for plague. Fleas were collected from the examined animals and from randomly selected residential houses. A total of 241 rodents, 1 Crocidura spp, 43 dogs, 12 cats and 4 slender mongooses were involved in the survey. Of the rodents, 14.5% were infested with fleas, which comprised of Xenopsylla brasiliensis (45.8%) and Dinopsyllus lypusus (54.2%), with an overall population density of 0.2 fleas/animal. Thirty one (72.1%) of the dogs were infested with fleas, all of which were Ctenocephalides spp. Thirty five (63.3%) houses were infested with fleas whose population was composed of Ctenocephalides spp, Pulex irritans, Tunga penetrans and Echinophaga gallinacea. Infected rodents were found in all the villages while the infected dog was found at Rhotia-Kati. Nineteen (11%) of the rodents and one (2%) dog harboured specific plague antibodies. It was broadly concluded that sylvatic plague was endemic in Karatu district and Ngorongoro Conservation Area and that outbreaks of the disease can occur in the area any time if and when relevant conditions become favourable. Prompt application of appropriate preventive and control measures and survey for substantiating the status in the Lake Manyara National Park, which is adjacent to some of the infected villages, are recommended.