\ud Detection and Monitoring of Insecticide Resistance in Malaria Vectors in Tanzania Mainland\ud

\ud Vector control is a major component of the global strategy for malaria control which aims to prevent parasite transmission mainly through interventions targeting adult Anopheline vectors. Insecticide treated nets (ITNs) and indoor residual spraying (IRS) are the cornerstone of malaria vector control programmes. These major interventions in most cases use pyrethroid insecticides which are also used for agricultural purposes. With widespread development of resistance to pyrethroid insecticides in malaria vectors raises concern over the sustainability of insecticide-based interventions for malaria control. Therefore, close monitoring of performance of the insecticides against malaria vectors is essential for early detection and\ud management of resistance. To measure pyrethroid susceptibility in populations of malaria vectors in Tanzania and to test the efficacy of LLINs/ITNs and insecticide residues on sprayed wall substrates in the IRS operation areas. In 2011 the National Institute for Medical Research (NIMR) in collaboration with National Malaria Control Programme (NMCP) conducted large scale surveillance to determine the countrywide susceptibility levels of malaria vectors to insecticides used for both public health and agricultural purposes. Anopheles gambiae Giles s.l. were collected during national surveys and samples of LLINs/ITNs in the 14 sentinel sites and houses from the IRS areas were randomly selected for bioassays to test the efficacy and insecticide residual effects on sprayed wall substrates respectively. Wild adult mosquitoes for susceptibility testing were collected by resting catches indoors. Net traps (outdoors and indoors) were set up to enhance catches. WHO Susceptibility kits were used to test for resistance status using test papers: Lambdacyhalothrin 0.05%, Deltamethrin 0.05%, Permethrin 0.75%, DDT 4%, Propoxur 0.1% and Fenitrothion 1%. The quality of the test paper was checked against a laboratory susceptible An. gambiae Kisumu strain. Knockdown effect and mortality were measured in standard WHO susceptibility tests and cone bio-efficacy tests. Whereas, con bioassays on treated walls and ITNs were conducted using the laboratory susceptible An. gambiae Kisumu strain. The results from the surveillance recorded continued susceptibility of malaria vectors to commonly used insecticides. However, there were some isolated cases of resistance and/or reduced susceptibility to pyrethroid insecticides which may not compromise the current vector control interventions in the country. Anopheles gambiae s.l. showed resistance (15-28%) to each of the pyrethroids and to DDT but not to Organophosphates (Propoxur 0.1%), and Carbamates (Fenitrothion 1%). The information obtained from this surveillance is expected to be used to guide the National Malaria Control Programme on the rational selection of insecticides for malaria vector control and for the national mitigation plans for management and containment of malaria vector resistance in the country. The current observation warrants more vigilant monitoring of the susceptibility of malaria mosquitoes to commonly used insecticides in areas found with resistance and/or reduced levels of susceptibility of malaria vectors to insecticides, particularly in areas with heavy agricultural and/or public health use of insecticides where resistance is likely to develop. The current survey covered malaria vectors only and not the non malaria vectors (nuisance) mosquitoes such as Culex. Similar monitoring of insecticide susceptibility of this non malaria vectors may be needed to ensure public motivation for sustained use of ITNs/LLINs in the country. The surveillance leading to these results received funding from PMI/USAID through RTI International with Sub Agreement Number 33300212555.\u

Spatial patterns of zooplankton distribution and abundance in relation to phytoplankton, fish catch and some water quality parameters at Shirati bay, lake victoria-Tanzania

Spatial patterns and abundance of zooplankton in aquatic habitats are important determinants for production of fish species, invertebrates and availability of phytoplankton. Weekly monitoring for zooplankton abundance was conducted in Shirati Bay, Lake Victoria, to explore their spatial patterns in relation to phytoplankton, fish catch and some water quality parameters. The vertical distribution of zooplankton was generally higher close to the bottom as compared to surface waters of the lake. Zooplankton vertical distribution positively correlated with water transparency (r = 0.680, p = 0.011). The horizontal abundance of zooplankton was not significantly different amongst the three stations (p = 0.5143). While Copepoda was the dominant group in terms of composition, Rotifera had the highest diversity indices of all the zooplankton groups obtained. The abundance of nauplius larvae was significantly higher than that of the copepodites (p = 0.022). Nile perch, Lates niloticus dominated the total catches (47%) followed by Nile tilapia, Oreochromis niloticus (29%) and haplochromines (21%). The abundance of haplochromines and juvenile fishes correlated significantly with the abundance of zooplankton (r = 0.856, p = 0.002 and r = 0.58, p = 0.038, respectively). The current study revealed that zooplankton vertical distribution at Shirati Bay is mainly controlled by water transparency and predation by juvenile Nile perch, Nile tilapia and haplochromines.Keywords: chlorophyll-a; calanoid; cyclopoid; nauplius larvae; juvenile fis

The reptiles of Mkomazi National Park, Tanzania an updated checklist with some aspects of biogeography

The Mkomazi National Park (MNP) is a protected area representing three major biomes, yet it remains poorly known from a herpetological perspective. Intensive surveys for reptiles were carried out in the MNP during dry and wet seasons in 2018, with the main focus of updating the existing data and assessing the influence of the three biomes on the park’s species composition. Various methods were used to document 55 species, most of which were found during the dry season. The checklist of reptiles of MNP is now updated to 73 species, 97% of which are typical of the Somalia-Maasai biome, equivalent to 54% of all Somalia-Maasai biome species in Tanzania. The MNP was found to be the most discordant in species composition from the contiguous Pare and Usambara Mountains, the latter two areas harbouring Afromontane forest-dependent species. We recommend surveys at Kinondu, Ibaya and Maji Kununua hills and foothills along the West Usambara and South Pare Mountains in order to confirm Afromontane species in MNP. Keywords: Herpetofauna, inventory, Somalia-Maasai, biodiversity, conservatio

Supply chains in times of crisis: evidence from Kenya’s production networks

Trading relationships between suppliers and buyers play a key role in transmitting both local and international shocks. We use rich transaction-level data from Kenya to study the relevance of a firm’s domestic network position and links to international supply chains in determining its trajectory during the COVID-19 crisis. We document that firms with varying degrees of exposure to import and export markets differ substantially in terms of their size and age profile. The specialisation of direct importers, often intermediaries, on international markets made them very vulnerable to the initial COVID-19 shock. Exporters, one-third of which operate in primary sectors, experienced a less drastic downturn. We find that both importers and exporters adjust their domestic supply chains in response to international trade shocks. Sourcing from international markets crowds in domestic purchases, while sales abroad and at home are substitutes. Diversified domestic networks further helped to mitigate the impact of severe shocks like the COVID-19 crisis and contributed to a stronger recovery

Evaluating the Effect of Preventative Trimming on Distance from the Sole Surface to the Distal Phalanx Using Ultrasonography for Lameness Prevention in Pasture-Based Dairy Cows

One common management strategy used to reduce the risk of lameness is prophylactic claw trimming. However, in pasture-based cattle, there is a concern that the immediate reduction in sole thickness resulting from sole trimming will lead to medium-to-long-term reductions in sole thickness, which may increase the risk of lameness. Nevertheless, there is a lack of data on sole thickness and trimming in pasture-based cows. Therefore, the aim of this study was to evaluate the effect of trimming on sole thickness over the medium-to-long term, as estimated using the ultrasound-measured distance from the external claw sole surface to the distal phalanx (DDP) and of DDP on the interval between calving and increased locomotion scores. A total of 38 cows were randomly selected from a 940-cow spring calving dairy farm in the North Island of New Zealand; 18 were allocated to the ultrasound hoof-trimming group and 20 were allocated to the ultrasound non-trimming group. Starting in May 2018, at the end of the 2017/18 lactation, ultrasound measurements of DDP of the right hind hoof were made on all 38 cows, and the hindlimbs of the trimming group cows were trimmed by an experienced professional hoof trimmer using the five-step Dutch method. This was repeated in October 2018 (early lactation) and May 2019 (late lactation). After calving, the cows were locomotion scored fortnightly until the end of lactation using the 4-point (0–3) scale DairyNZ system. The effect of DDP on the interval between calving and the first locomotion scores ≥1 and ≥2 was assessed using Cox proportional hazards models, and the association between trimming and DDP was explored using linear mixed models. The results suggest that DDP has no effect on the time to locomotion scores ≥1 or ≥2, although the wide confidence intervals of the latter suggest that more data are needed before any definitive conclusions can be drawn. The study failed to find any clinically important impact of prophylactic trimming on DDP. This is likely related to the finding that cows with the highest DDP at the first trimming were identified by the hoof trimmer as those needing the most trimming. The results of this study thus suggest that if the Dutch five-step method is properly applied, it is unlikely to affect sole thickness over the short-to-medium term in pasture-based cattle

Assessing Alternatives to Locomotion Scoring for Detecting Lameness in Dairy Cattle in Tanzania: Infrared Thermography

Lameness detection is a significant challenge. Locomotion scoring (LS), the most widely used system for detecting lameness, has several limitations, including its subjective nature and the existence of multiple systems, each with its own advantages and disadvantages. Therefore, this study aimed to evaluate whether the foot skin temperature (FST) of hind limbs, as measured using infrared thermography (IRT), could potentially be used as an alternative on Tanzanian dairy farms. Each of the three study farms were visited twice during the afternoon milking on consecutive days, with a total of 170 cows assessed. DairyNZ LS (4-point scale (0–3)) was undertaken on the first day as the cows exited the milking parlour after being milked, while on the following day, the plantar aspect of the hind limbs of the cows was thermally imaged while they were standing in the milking parlour, using a handheld T650sc forward-looking infrared camera. Mean FST was higher for cows with a locomotion score of 1 than those with a score of 0; higher for cows with a locomotion score of 2 than those with a score of 1; and higher for cows with a locomotion score of 3 than those with a score of 2, with each one-unit locomotion score increase being associated with a 0.57 °C increase in mean temperature across all zones. The optimal cut-off point of 38.0 °C for mean temperature across all zones was identified using a receiver operator characteristic curve. This cut-off point had a sensitivity of 73.2% and a specificity of 86.0% for distinguishing cows with a locomotion score ≥ 2 (clinical lameness). The prevalence of clinical lameness across all three farms was 33%, which meant that only 72% of cows with a mean FST across all zones ≥ 38.0 °C had been identified as clinically lame using LS. This study confirmed that IRT has the potential to be used to detect lameness on Tanzanian dairy farms. However, before it can be widely used, improvements in accuracy, especially specificity, are needed, as are reductions in equipment (IR camera) costs

Profile of plasma lipids and degree of derangements among the elderly of Morogoro region, Tanzania

Tanzania Journal of Health Research, Volume 16, Number 4, October 2014Changes in lifestyles and ageing have been associated with growing rates of modifiable cardiovascular risk factors (CRF). Dyslipidemia is one of the CRF associated with numbers of cardiovascular diseases. This descriptive cross-sectional study was conducted to determine the profile and degree of derangements of plasma lipids among 300 (176 females and 124 males) elderly individuals aged ≥60 years in Morogoro, Tanzania. The calorimetric enzymatic methods and the Friedewal’s equation were used for determination of cholesterols and triglycerides (TG). Social and demographic characteristics were gathered by structured questionnaires. The logistic regression models were used to identify the determinants of abnormal serum lipids level. Mean Total Cholesterols (TC) and Low Density Lipoprotein Cholesterols (LDL-C) in females exceeded significantly that of males. Mean TC, LDL-C as well as TG (mg/dL) declined significantly with age while mean High Density Lipoprotein Cholesterols (HDL-C) also declined but only slightly. Elderly females were two times more likely to have elevated TC (OR=2.11; 95% CI: 1.04-4.28: P=0.05) and LDL-C (OR=2.15; 95% CI: 1.17-3.97: P=0.019) and three times to have lowered HDL-C (OR=3; 95% CI: 1.97-5.30: P<0.001) than males. Urban residents were about two times more likely to have elevated LDL-C (OR=1.84; 95% CI: 1.04-3.25: P=0.047) than their rural counterparts. Body Mass Index of ≥30 kg/m 2 was also associated with elevated LDL-C (OR=1.89; 95% CI: 1.05- 3.42: P=0.045) and lowered HDL-C (OR=2.18; 95% CI: 1.3-3.65: P=0.004), respectively. The present study has established the profile and level of derangements of serum lipids among the elderly of Morogoro region in Tanzania. It appears that, female sex and BMI of ≥ 30kg/ m 2 are significant factors for elevated TC, LDL-C and lowered HDL-C while urban life is a significant factor for elevated LDL-C