South-eastern Tanzania Research Articles

Efficacy of the spatial repellent product Mosquito Shield™ against wild pyrethroid-resistant Anopheles arabiensis in south-eastern Tanzania

BackgroundSpatial repellents that create airborne concentrations of an active ingredient (AI) within a space offer a scalable solution to further reduce transmission of malaria, by disrupting mosquito behaviours in ways that ultimately lead to reduced human-vector contact. Passive emanator spatial repellents can protect multiple people within the treated space and can last for multiple weeks without the need for daily user touchpoints, making them less intrusive interventions. They may be particularly advantageous in certain use cases where implementation of core tools may be constrained, such as in humanitarian emergencies and among mobile at-risk populations. The purpose of this study was to assess the efficacy of Mosquito Shield™ deployed in experimental huts against wild, free-flying, pyrethroid-resistant Anopheles arabiensis mosquitoes in Tanzania over 1 month.MethodsThe efficacy of Mosquito Shield™ transfluthrin spatial repellent in reducing mosquito lands and blood-feeding was evaluated using 24 huts: sixteen huts were allocated to Human Landing Catch (HLC) collections and eight huts to estimating blood-feeding. In both experiments, half of the huts received no intervention (control) while the remaining received the intervention randomly allocated to huts and remained fixed for the study duration. Outcomes measured were mosquito landings, blood-fed, resting and dead mosquitoes. Data were analysed by multilevel mixed effects regression with appropriate dispersion and link function accounting for volunteer, hut and day.ResultsLanding inhibition was estimated to be 70% (57–78%) [IRR 0.30 (95% CI 0.22–0.43); p < 0.0001] and blood-feeding inhibition was estimated to be 69% (56–79%) [IRR 0.31 (95% CI 0.21–0.44; p < 0.0001] There was no difference in the protective efficacy estimates of landing and blood-feeding inhibition [IRR 0.98 (95% CI 0.53–1.82; p = 0.958].ConclusionsThis study demonstrated that Mosquito Shield™ was efficacious against a wild pyrethroid-resistant strain of An. arabiensis mosquitoes in Tanzania for up to 1 month and could be used as a complementary or stand-alone tool where gaps in protection offered by core malaria vector control tools exist. HLC is a suitable technique for estimating bite reductions conferred by spatial repellents especially where direct blood-feeding measurements are not practical or are ethically limited.

Common predators and factors influencing their abundance in Anopheles funestus aquatic habitats in rural south-eastern Tanzania.

The role of larval predators in regulating the Anopheles funestus population in various malaria-endemic countries remains relatively unknown. This study aimed to investigate the common predators that co-exist with Anopheles funestus group larvae and evaluate factors that influence their abundance in rural south-eastern Tanzania. Mosquito larvae and predators were sampled concurrently using standard dipper (350 ml) or 10 L bucket in previously identified aquatic habitats in selected villages in southern Tanzania. Predators and mosquito larvae were identified using standard identification keys. All positive habitats were geo-located and their physical features characterized. Water physicochemical parameters such as dissolved oxygen (DO), pH, electrical conductivity (EC), total dissolved solids (TDS) and temperature were also recorded. A total of 85 previously identified An. funestus aquatic habitats in nine villages were sampled for larvae and potential predators. A total of 8,295 predators were sampled. Of these Coenagrionidae 57.7% (n = 4785), Corixidae 12.8% (n = 1,060), Notonectidae 9.9% (n = 822), Aeshnidae 4.9% (n = 405), Amphibian 4.5% (n = 370), Dytiscidae 3.8% (n = 313) were common. A total of 5,260 mosquito larvae were sampled, whereby Anopheles funestus group were 60.3% (n = 3,170), Culex spp. 24.3% (n = 1,279), An. gambie s.l. 8.3% (n = 438) and other anophelines 7.1% (n = 373). Permanent and aquatic habitats larger than 100m2 were positively associated with An. funestus group larvae (P<0.05) and predator abundance (P<0.05). Habitats with submerged vegetation were negatively associated with An. funestus group larvae (P<0.05). Only dissolved oxygen (DO) was positively and significantly affect the abundance of An. funestus group larvae (P<0.05). While predators' abundance was not impacted by all physicochemical parameters. Six potential predator families were common in aquatic habitats of An. funestus group larvae. Additional studies are needed to demonstrate the efficacy of different predators on larval density and adult fitness traits. Interventions leveraging the interaction between mosquitoes and predators can be established to disrupt the transmission potential and survival of the An. funestus mosquitoes.

Sesame production constraints, variety traits preference in the Southeastern Tanzania: Implication for genetic improvement

Despite the prominence of sesame production in household and national economies, its productivity remains quite low (405.6 kg/ha) in comparison to the potential output of 1500 kg/ha. Low sesame production threatens the employment of 481,115 smallholder producers in Tanzania's sesame sub-sector. In view of that, to enhance sesame productivity, the present study lured to find out what restrictions upset sesame cultivation and spot farmers' desired traits for sesame cultivars in southeastern Tanzania. A semi-structured questionnaire and interview checklist were adopted to obtain data from 240 sesame cultivators. The findings revealed that the key impediments inhibiting sesame production in the studied regions included the prevalence of insect-pests (23.6%), diseases (15.7%), drought (10.1%), weed infestation (9.9%), insufficient capital (7.9%), high seed costs (7.6%), and a dearth of enhanced seeds (6.8%). Furthermore, according to sesame growers, the most important criteria in sesame variety selection were high yielding (45.7%), resistance to insect-pests and diseases (20.8%), early maturity (15.4%), appealing seed color (8.8%), and drought tolerance (6.3%). Meanwhile, it was reported that the market valued sesame cultivars with white grain colour, large grain size, clean seeds, and high oil content. Hence, the present study recommends enhanced breeding for improved sesame variety development with the desired traits by farmers and post-farm operators.

Contributions to the Flora of Tropical East Africa.

Tropical East Africa (TEA) is one of the most important biodiversity hotspots on the planet. Its rich flora diversity and inventory have been clearly recognized after the publication of the last volume of the Flora of Tropical East Africa (FTEA) in 2012. However, many new and newly recorded taxa have been named and documented since the publication of the first volume of FTEA in 1952. In this study, we comprehensively compiled new taxa and new records by reviewing the literature on the taxonomic contributions of vascular plants in TEA from 1952 to 2022. Our list includes 444 new and newly recorded species belonging to 81 families and 218 genera. Among these taxa, 94.59% of the plants are endemic to TEA and 48.42% are herbs. Additionally, members of Rubiaceae and Aloe are the most numerous family and genus respectively. These new taxa are unevenly distributed in TEA, but are found mainly in areas of high species richness, such as coastal, central and western areas of Kenya, central and southeastern Tanzania. This study offers summative assessment of the newly recorded flora inventory in TEA and provides recommendations for future research on plant diversity survey and conservation.

Coastal communities’ livelihoods conditioned by resource use dynamics and changing environments in Lindi Region, South-Eastern Tanzania

Coastal and marine resources are significant drivers of coastal livelihoods, population growth along the coast, and boosting farm and off-farm job generation. However, the use of coastal resources has been extremely variable, resulting in ups and downs in the productivity of coastal communities. This cross-sectional study investigated the root causes of these coastal resource dynamics and how they affect household livelihood. The household questionnaire survey was used as the main instrument, aided by focus group discussions, key informant interviews, and field observations in data collection. Data were collected from 100 randomly selected households, four focus groups (one for each ward), and eight key informant interviews. Household shocks (both climate and non-climate), livelihood diversification, government policy changes, and aging all influence household decisions on which livelihood alternative to pursuing. Coastal and marine resource extraction, on the other hand, increases or decreases in magnitude as households strive to sustain income levels, driven by prices set by demand and supply in the phases of environmental change. Changes in fiscal gains cause the linear relationship between yield and natural resource utilization. Nonetheless, the low productivity of coastal and marine ecosystems and terrestrial ecosystems, as a result of environmental change, has prompted the deployment of modern resource extraction methods to adapt to the changing environment. Nonetheless, despite the paradox, the natural gas discovery gives coastal towns a new hope for survival. Apart from investments, policies must address the lack of access to current technologies, the compensation range, and support for community livelihoods.

Small-scale field evaluation of transfluthrin-treated eave ribbons and sandals for the control of malaria vectors in rural Tanzania

BackgroundEarly-evening and outdoor-biting mosquitoes may compromise the effectiveness of frontline malaria interventions, notably insecticide-treated nets (ITNs). This study aimed to evaluate the efficacy of low-cost insecticide-treated eave ribbons and sandals as supplementary interventions against indoor-biting and outdoor-biting mosquitoes in south-eastern Tanzania, where ITNs are already widely used.MethodsThis study was conducted in three villages, with 72 households participating (24 households per village). The households were divided into four study arms and assigned: transfluthrin-treated sandals (TS), transfluthrin-treated eave ribbons (TER), a combination of TER and TS, or experimental controls. Each arm had 18 households, and all households received new ITNs. Mosquitoes were collected using double net traps (to assess outdoor biting), CDC light traps (to assess indoor biting), and Prokopack aspirators (to assess indoor resting). Protection provided by the interventions was evaluated by comparing mosquito densities between the treatment and control arms. Additional tests were done in experimental huts to assess the mortality of wild mosquitoes exposed to the treatments or controls.ResultsTERs reduced indoor-biting, indoor-resting and outdoor-biting Anopheles arabiensis by 60%, 73% and 41%, respectively, while TS reduced the densities by 18%, 40% and 42%, respectively. When used together, TER & TS reduced indoor-biting, indoor-resting and outdoor-biting An. arabiensis by 53%, 67% and 57%, respectively. Protection against Anopheles funestus ranged from 42 to 69% with TER and from 57 to 74% with TER & TS combined. Mortality of field-collected mosquitoes exposed to TER, TS or both interventions was 56–78% for An. arabiensis and 47–74% for An. funestus.ConclusionTransfluthrin-treated eave ribbons and sandals or their combination can offer significant household-level protection against malaria vectors. Their efficacy is magnified by the transfluthrin-induced mortality, which was observed despite the prevailing pyrethroid resistance in the study area. These results suggest that TER and TS could be useful supplementary tools against residual malaria transmission in areas where ITN coverage is high but additional protection is needed against early-evening and outdoor-biting mosquitoes. Further research is needed to validate the performance of these tools in different settings, and assess their long-term effectiveness and feasibility for malaria control.

“A disease that God has given me” patients and caregivers’ perspectives on diabetes in southeastern Tanzania

BackgroundPrompt diagnosis and appropriate management of diabetes has the potential of improving survival and patient health outcomes. Yet many diabetes patients present themselves to health facilities at an advanced stage of the disease which complicates its management. Individual perceptions about diseases are known to play a critical role in informing responses and actions including seeking health care and self-care practices. However, little is documented in Tanzania regarding the perspectives of diabetes patients and their caregivers about the disease especially in rural settings.MethodsWe conducted 26 in-depth interviews involving 19 diabetes patients and 7 diabetes patient caregivers to explore in detail their perspectives on diabetes as a disease. Data was analyzed using thematic analysis with the help of NVivo9.ResultsBoth patients and caregivers expressed mixed perceptions on diabetes causes. In addition to heredity, and the failure of the pancreas to function well, lifestyle factors including lack of physical activity and eating too many sugary and oily foods were common reported causes. However, none of the participants were clear on the mechanisms between the perceived causes and the actual occurrence of the disease. Perception on susceptibility to diabetes was low even among participants with the disease as they reported not having ever thought of getting the condition before they were diagnosed. Some caregivers expressed worry and fear on their susceptibility to inheriting diabetes from their relatives who had the condition. Diabetes was perceived as a severe and life-threatening condition that can easily cause death if not well managed. Participants indicated uncertainty on its prevention.ConclusionThis study shows mixed perspectives on the causes, susceptibility, severity and prevention of diabetes which were informed by the participants’ limited knowledge and awareness about the disease. Interventions to strengthen responses to diabetes, which include buy-in from the patients and their caregiver’s perspectives are essential to improve prevention, early diagnosis and appropriate management in rural settings.

Relationships between biological age, distance from aquatic habitats and pyrethroid resistance status of Anopheles funestus mosquitoes in south-eastern Tanzania

BackgroundMalaria transmission can be highly heterogeneous between and within localities, and is influenced by factors such as survival and biting frequencies of Anopheles mosquitoes. This study investigated the relationships between the biological age, distance from aquatic habitats and pyrethroid resistance status of Anopheles funestus mosquitoes, which currently dominate malaria transmission in south-east Tanzania. The study also examined how such relationships may influence malaria transmission and control.MethodsFemale An. funestus were collected in houses located 50–100 m, 150–200 m or over 200 m from the nearest known aquatic habitats. The mosquitoes were exposed to 1×, 5× and 10× the diagnostic doses of deltamethrin or permethrin, or to the synergist, piperonyl butoxide (PBO) followed by the pyrethroids, then monitored for 24 h-mortality. Ovaries of exposed and non-exposed mosquitoes were dissected to assess parity as a proxy for biological age. Adults emerging from larval collections in the same villages were tested against the same insecticides at 3–5, 8–11 or 17–20 days old.FindingsMosquitoes collected nearest to the aquatic habitats (50-100 m) had the lowest mortalities compared to other distances, with a maximum of 51% mortality at 10× permethrin. For the age-synchronized mosquitoes collected as larvae, the insecticide-induced mortality assessed at both the diagnostic and multiplicative doses (1×, 5× and 10×) increased with mosquito age. The highest mortalities at 1× doses were observed among the oldest mosquitoes (17–20 days). At 10× doses, mortalities were 99% (permethrin) and 76% (deltamethrin) among 8–11 day-olds compared to 80% (permethrin) and 58% (deltamethrin) among 3–5 day-olds. Pre-exposure to PBO increased the potency of both pyrethroids. The proportion of parous females was highest among mosquitoes collected farthest from the habitats.ConclusionIn this specific setting, older An. funestus and those collected farthest from the aquatic habitats (near the centre of the village) were more susceptible to pyrethroids than the younger ones and those caught nearest to the habitats. These findings suggest that pyrethroid-based interventions may remain at least moderately effective despite widespread pyrethroid-resistance, by killing the older, less-resistant and potentially-infective mosquitoes. Further studies should investigate how and whether these observations could be exploited to optimize malaria control in different settings.

Comparative evaluation of different versions of exposure-free mosquito electrocuting traps and barrier screen trap for monitoring outdoor densities and biting time phenotypes by malaria and filariasis vectors in Tanzania

BackgroundEstimating human exposure to mosquito vectors is crucial for the prediction of malaria transmission and intervention impact. The human landing catch method is frequently used to directly measure estimate exposure rates; however, there has been an increasing shift from this method to exposure-free alternatives, such as the mosquito electrocuting traps (MET) and other approaches. While these latter methods can provide robust and representative values of human exposure and mosquito density, they often still require a human volunteer, which poses logistical challenges. Additionally, in the case of the MET, the early MET prototype (METe) required human volunteers to wear protective clothing that could be uncomfortable. We investigated two alternative trapping approaches to address these challenges by comparing the performance of the METe prototype to: (i) a modified caged MET prototype that offers full protection to users (METc) and (ii) a barrier screen trap (BST) designed to passively sample (host-seeking and blood-fed) mosquitoes outdoors without requiring a human participant.MethodsThe relative performance of the METe, METc and BST were evaluated in a 3 × 3 Latin square field experiment design conducted in south-eastern Tanzania over 12 nights of sampling. The outcomes of interest were the nightly catch of mosquitoes and biting time estimates.ResultsThe METc and BST caught similar numbers of An. arabiensis as the METe (relative ratio [RR] = 0.76, 95% confidence interval [CI]: 0.42–1.39, P = 0.38 and RR = 1.13, 95% CI: 0.63–2.04, P = 0.69, respectively). Similarly, the METc and BST caught similar numbers of Culex spp. as the METe (RR = 0.87, 95% CI: 0.62–1.22, P = 0.42 and RR = 0.80, 95% CI: 0.57–1.12, P = 0.199, respectively). All three trapping methods indicated a similar pattern of biting activity by An. arabiensis and Culex spp., characterized by biting starting in the early evening (18:00–22:00), peaking when people are typically sleeping (22:00–05:00) and dropping off drastically toward the morning (05:00–07:00).ConclusionsThe modifications made to the METe design to improve user comfort and remove the need for protective clothing did not result in an underestimation of mosquito vector abundance nor misrepresentation of their biting time pattern. We recommend the METc for use over the METe design. Similarly, the BST demonstrated potential for monitoring malaria and filariasis vector densities in Tanzania.Graphical

Pollination potential of African honey bees, Apis mellifera (litorea): (Hymenoptera: Apidae) in sunflower, Helianthus annuus production in South-Eastern Tanzania

Sunflower, Helianthus annuus, is one of the major cash crops in Tanzania. Despite the importance of the crop, its productivity is still low. In that respect, farmers have been experiencing poor seed-set in sunflowers leading to recorded lower yields. The introduction of honey bees, Apis mellifera, in sunflower production has for a long time been considered an effective strategy for improving sunflower productivity; however, studies on the potential of this phenomenon particularly in Tanzania have been limited. We conducted experiments between July and December 2019 in Mtwara Tanzania, to investigate the potential of honey bees in improving sunflower production. Findings revealed that the weight of sunflower seeds per head in the plots colonized with honey bees was 32.15 g, accounting for three and half times higher than the case without any pollinators (9.41 g). We recorded a significantly (Kruskal-Wallis Test H = 25.81, χ2 prob = p < 0.001) higher 1000-sunflower seed weight of 53.68 g for plots with honey bees vis-a-vis plots with other pollination treatments (wild pollinators = 42.07 g, without pollinators 29.51 g). The percentage of chaffiness was lower in the plots with managed honey bees and wild pollination, accounting for a reduction of 28.25% (for managed honey bees only) and 16.68% (for wild pollination) as compared to plots without pollinators. Therefore, the study results revealed that pollination services from managed honey bees are the appropriate strategies that can contribute to the improvement of sunflower productivity. Further studies based on different agroecological conditions are recommended.

The costs and benefits of certification for community forests managed by traditional peoples in south-eastern Tanzania

Community forests managed by indigenous, traditional, and local communities must be environmentally, socially, and economically sustainable for their benefits to persist. Certification of community forests communicates that products harvested there meet these standards. However, certification of community forests has been limited, particularly in Africa. Financial analysis, review of audit reports, and a survey of forest managers were used to explore monetary and non-monetary social costs and benefits of Forest Stewardship Council certification for 14 timberproducing community forests managed by traditional peoples in south-eastern Tanzania. Direct monetary costs of certification outweighed monetary benefits, threatening economic sustainability. Nevertheless, forest managers believed that community forests should retain certification because they valued its non-monetary benefits, which were consistent with the Forest Stewardship Council's social principles. This study demonstrates that certification of community forests can help indigenous and traditional peoples ensure safe working conditions, strengthen forest tenure rights, sustain multiple community benefits, and protect culturally-important sites, however, financial barriers persist.

Persistently high proportions of plasmodium-infected Anopheles funestus mosquitoes in two villages in the Kilombero valley, South-Eastern Tanzania

BackgroundIn south-eastern Tanzania where insecticide-treated nets have been widely used for >20 years, malaria transmission has greatly reduced but remains highly heterogenous over small distances. This study investigated the seasonal prevalence of Plasmodium sporozoite infections in the two main malaria vector species, Anopheles funestus and Anopheles arabiensis for 34 months, starting January 2018 to November 2020. MethodsAdult mosquitoes were collected using CDC-light traps and Prokopack aspirators inside local houses in Igumbiro and Sululu villages, where earlier surveys had found very high densities of An. funestus. Collected females were sorted by taxa, and the samples examined using ELISA assays for detecting Plasmodium circumsporozoite protein in their salivary glands. ResultsOf 7859 An. funestus tested, 4.6% (n = 365) were positive for Pf sporozoites in the salivary glands. On the contrary, only 0.4% (n = 9) of the 2382 An. arabiensis tested were positive. The sporozoite prevalence did not vary significantly between the villages or seasons. Similarly, the proportions of parous females of either species were not significantly different between the two villages (p > 0.05) but was slightly higher in An. funestus (0.50) than in An. arabiensis (0.42). Analysis of the 2020 data determined that An. funestus contributed 97.7% of all malaria transmitted in households in these two villages. ConclusionsIn contexts where individual vector species mediate most of the pathogen transmission, it may be most appropriate to pursue a species-focused approach to better understand the ecology of the dominant vectors and target them with effective interventions to suppress transmission. Despite the ongoing efforts on tackling malaria in the two study villages, there is still persistently high Plasmodium infection prevalence in local populations of An. funestus, which now carry ~97% of all malaria infections and mediates intense year-round transmission. Further reduction in malaria burden in these or other similar settings requires effective targeting of An. funestus.

Effects of agricultural pesticides on the susceptibility and fitness of malaria vectors in rural south-eastern Tanzania

BackgroundAgricultural pesticides may exert strong selection pressures on malaria vectors during the aquatic life stages and may contribute to resistance in adult mosquitoes. This could reduce the performance of key vector control interventions such as indoor-residual spraying and insecticide-treated nets. The aim of this study was to investigate effects of agrochemicals on susceptibility and fitness of the malaria vectors across farming areas in Tanzania.MethodsAn exploratory mixed-methods study was conducted to assess pesticide use in four villages (V1–V4) in south-eastern Tanzania. Anopheles gambiae (s.l.) larvae were collected from agricultural fields in the same villages and their emergent adults examined for insecticide susceptibility, egg-laying and wing lengths (as proxy for body size). These tests were repeated using two groups of laboratory-reared An. arabiensis, one of which was pre-exposed for 48 h to sub-lethal aquatic doses of agricultural pesticides found in the villages.ResultsFarmers lacked awareness about the linkages between the public health and agriculture sectors but were interested in being more informed. Agrochemical usage was reported as extensive in V1, V2 and V3 but minimal in V4. Similarly, mosquitoes from V1 to V3 but not V4 were resistant to pyrethroids and either pirimiphos-methyl or bendiocarb, or both. Adding the synergist piperonyl butoxide restored potency of the pyrethroids. Pre-exposure of laboratory-reared mosquitoes to pesticides during aquatic stages did not affect insecticide susceptibility in emergent adults of the same filial generation. There was also no effect on fecundity, except after pre-exposure to organophosphates, which were associated with fewer eggs and smaller mosquitoes. Wild mosquitoes were smaller than laboratory-reared ones, but fecundity was similar.ConclusionsSafeguarding the potential of insecticide-based interventions requires improved understanding of how agricultural pesticides influence important life cycle processes and transmission potential of mosquito vectors. In this study, susceptibility of mosquitoes to public health insecticides was lower in villages reporting frequent use of pesticides compared to villages with little or no pesticide use. Variations in the fitness parameters, fecundity and wing length marginally reflected the differences in exposure to agrochemicals and should be investigated further. Pesticide use may exert additional life cycle constraints on mosquito vectors, but this likely occurs after multi-generational exposures.Graphical

Intentions behind common and risky fires in south-eastern Tanzania

Human-set fires are a crucial component of African savannas, affecting ecosystem structure, carbon emissions, local hazards and livelihoods. Yet, most fire research in these ecosystems focuses on the fire ecology of protected areas. Research exploring fire regimes in inhabited landscapes remains limited, undermining opportunities for culturally and environmentally sustainable fire management. To address this gap, we used interviews in Tanzanian farming communities and remote sensing to identify intentions behind fire use and the perceived relative frequency and riskiness of fires set for different purposes. We found that the most common ignitions were intentional and important to livelihoods. Burning was adaptive, responsive to environmental conditions, and optimised for the intended outcome with the perceived riskiest fires intentionally spreading uncontrolled. Remote sensing showed that most of the total burned area was accounted for by fires during the late dry season when people burned for activities, such as field preparation, and when environmental conditions encouraged fire spread. Our findings offer an insight into fire regimes in inhabited landscapes, by exploring how intentions shape the fire regime at the landscape scale. We discuss how understanding these intentions and local priorities, including adaptive uses of fire, is key to sustainable fire management outside protected areas.

HIV status disclosure among adults attending care and treatment clinic in Kilombero district, South-Eastern Tanzania

BackgroundDisclosing HIV serostatus is important for HIV prevention and in reducing HIV transmission among communities. The present study assessed HIV disclosure patterns and its associated factors among adults in Kilombero district, Tanzania. MethodsA cross-sectional study was conducted among people living with HIV who visited Care and Treatment Clinic in Ifakara Town Council from September 2018-February 2019. A structured questionnaire was used to collect data, and the analysis was done by SPSS Version 20. ResultsA total of 102 participated into this study, 63 (61.8%) females and 39 (38.2%) males. The mean age (±SD) of participants was 34.37 (±10.9) years and people living with HIV were mostly (68%) in age group between 18 and 38. Despite the high rate of HIV disclosure 81 (79.4%) only 58% had disclosed their HIV results to their partners. In addition, most partcipants delayed the disclosure for six months and above. HIV disclosure was significantly higher in married participants than in single individuals (81.8% vs 68.5%; p < 0.001), and in participants aged 39–59 years (p = 0.06). The major reasons for non-disclosure include fear of losing their partners, felt ashamed of being HIV positive and fears of stigma. ConclusionAlthough the disclosure of HIV serostatus among the participants was high, the disclosure to their sex partners was moderate. Moreover, the study observed negative attitudes and delayed disclosure longer than six months. Interventions to promote disclosure of HIV and discouraging stigma and discriminations should be given priority.

Modelling the effect of fusarium oxysporum in transmission dynamics of fusarium wilt disease of cashew plants in context of South-Eastern Tanzania

Cashew nuts are the most important cash crop in Tanzania's south-eastern region, where cashew nut farming is the primary source of income for the majority of people. Aside from their importance, cashew plants are vulnerable to Fusarium wilt, a devastating disease. In particular study a system of equations for the model is formulated and analyzed qualitatively using the stability theorem of ordinary differential equation. The stability analysis indicates that the system is stable under the specified conditions. Furthermore, the analysis shows that an increase in transmission is determined by the rate of contact between susceptible plants and infected plants via root contact, whereas numerical results show that decomposed infected plants contribute to the growth of Fusarium oxysporum, increasing the disease outbreak.

Susceptibility status of major malaria vectors to novaluron, an insect growth regulator South-Eastern Tanzania.

Introductionapplication of Insect Growth Regulator (IGR) such as pyriproxyfen has shown a promising result in controlling malaria transmitting mosquitoes through autodissemination technique. Novaluron that inhibits the chitin development at mosquito larval stage present a promising candidate IGR for rotation with pyriproxyfen to prevent a chance of resistance development. This study assessed the susceptibility of immature stages of Anopheles arabiensis, Anopheles gambiae and Anopheles funestus to novaluron.Methodssusceptibility bioassays using technical grade novaluron (98% active ingredient) were performed inside the semi-field system using first instar larvae of Anopheles species. For each tested species, a total of 1500 larvae were used in the bioassay. Concentration range of 0.01 mg/l to 2 mg/l of novaluron were tested to establish Lethal Concentration (LC) sufficient to kills 50%, 90% and 99% of the exposed larvae by using log-dose response analysis.Resultsof the tested mosquitoes, Anopheles gambiae were highly susceptible to novaluron followed by An. Arabiensis and then An. funestus. Lethal concentrations, LC50, LC90 and LC99 (95%CI) in mg/l for An. gambiae were 0.018, 0.332 and 2.001 respectively. For An. arabiensis were 0.026, 0.546 and 2.013; and for An. funestus were 0.032, 1.00 and 5.580. High larval mortality was recorded at high concentration (2mg/L), with 80% mortality within 3 days post exposure.Conclusionthe study demonstrates the efficacy of novaluron in controlling Anopheles mosquito species at immature stages via larval mortality. These findings warrant further testing of novaluron for autodissemination by different vector species for its inclusion in rotation to prevent development of resistance.

Biodiversity hotspot revisited: reptile and amphibian assemblages of the Uluguru Mountain Forest Reserves, south-eastern Tanzania

ABSTRACT Although the knowledge about the Tanzanian reptiles and amphibians has drastically increased in recent years, the knowledge on the amphibian and reptile fauna of the remaining forest reserves of the Uluguru Mountains (UMs) is only partially known. Amphibians and reptiles were studied in 17 forest reserves and sampled using diurnal and nocturnal time-constrained visual encounter surveys, acoustic surveys and opportunistic searches. A total of 51 quadrats of 25 × 25 m were randomly established on the forest floor, totalling 459 person-hours of sampling effort. Overall, 54 herpetofauna species (27 amphibian and 27 reptile species) were recorded from the area, including two anurans and seven reptile species, which are new records for the region. The estimated Chao1 species richness for the study region was 51 for amphibians and 76 for reptiles. Amphibian and reptile species composition did not differ significantly across the forest reserves, but similarities in species composition of different levels were evident across the reserves. For both communities, α-diversity and relative abundance did not vary significantly across the reserves. Based on multiple regression analyses, leaf-litter anuran species richness was positively influenced by percentage canopy cover, whereas abundance was negatively influenced by total fragment size. Partial correlations showed that variation in leaf-litter anuran abundance was explained by relative humidity, percentage canopy cover and soil moisture, while controlling for altitude. Percentage canopy cover was also the best predictor of species richness of leaf-litter anurans. Overall, these findings highlight the importance of protecting the UMs forest reserves for herpetofauna conservation.

Coupled Model Intercomparison Project phase 6 evaluation and projection of East African precipitation

AbstractThis study evaluates the performance of 43 Coupled Model Intercomparison Project phase 6 (CMIP6) models in reproducing annual cycle, climatology, and trend of observed precipitation over East Africa during 1950–2014. The results show that the CMIP6 models display good performance in simulating the annual cycle (i.e., bimodal pattern) of East African precipitation; however, most models and the multimodel ensemble mean (ENSEM) underestimate the March to May (MAM) precipitation while overestimating the October to December (OND) precipitation. Spatially, most models seem to perform relatively better in simulating OND precipitation compared to MAM season, despite wet (dry) biases over most parts of East Africa with the wettest (driest) biases over the Lake Victoria basin (southeastern Tanzania) during OND (MAM). The metrics have shown that nine models (i.e., MPI‐ESM1‐2‐HR, AWI‐CM‐1‐MR, MPI‐ESM1‐2‐LR, IPSL‐CM6A‐LR, CAS‐ESM2‐0, BCC‐CSM2‐MR, NorESM2‐LM, CESM2‐WACCM, and CMCC‐CM2‐SR5) outperform the other individual models during both OND and MAM. Compared with individual models, the ENSEM better agrees with the observation. Besides, the ENSEM and most models can reproduce the increasing trend in OND precipitation as observed over East Africa. However, for the secular change of MAM precipitation, given that half of the models show increasing trends, the ENSEM simulation produces an inconsistent trend with the observation. The ensemble of the above nine models with better performance projects an increase of precipitation averaged over East Africa in both MAM and OND by the end of the 21st century, with larger changes under SSP5‐8.5 than under SSP2‐4.5. Spatially, the largest percentage increase in MAM precipitation is projected to occur in central Tanzania and northwestern Kenya, while southeastern Tanzania shows the greatest percentage decrease. The projected percentage increases in OND precipitation are larger in the northeastern highlands of Tanzania and northwest Kenya.

Dietary diversity among households living in Kilombero district, in Morogoro region, South-Eastern Tanzania

Adequate nutrition is essential for good health and active life. However, diets in most low and middle-income households lack diversity, especially in settings where people eat predominantly starchy foods. In this study, we assessed the associations between socio-economic status and household dietary diversity in families living in South-eastern Tanzania. A cross-sectional questionnaire was administered to 925 parents of school children in four wards in South-eastern Tanzania, as part of a trial; assessing the effects of physical activity and micronutrient supplementation on overall growth, health and well-being of school children. The dietary intake was assessed by 24-h dietary recall and dietary diversity score (DDS) was calculated. Socio-economic status was derived from a weighted score using principal component analysis (PCA). Multinomial logistic regression was used to investigate the association between dietary diversity and socio-economic status. This baseline data assessment was completed in July and August 2019. Cereals, oils and fats were the most consumed food groups, legumes were the most common source of protein and fish was the most common animal protein. More than three quarters of the households had medium dietary diversity (MDD). Higher household education and large farm size were the only factors significantly associated with having high dietary diversity. A majority of the households in South-eastern Tanzania have medium dietary diversity, comprised of cereal, fats and oils and proteins. Having high dietary diversity was associated with higher education and large farm sizes. Improving community members’ knowledge and awareness of nutritional benefits could improve the dietary diversity at household level. • Majority of respondents had primary school education and do farming as their main income generating activity. • Cereals and oils and fats were the most consumed food groups. • More than three quarters of the households had medium dietary diversity. • Household dietary diversity influenced by some factors like education and farm size.