Browsing by Author "Nkwengulila, Gamba"
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Item Activity of Cinnamomum Osmophloeum Leaf Essential Oil Against Anopheles Gambiae s.s(BioMed Central, 2014) Mdoe, France P.; Cheng, Sen-Sung; Msangi, Shandala; Nkwengulila, Gamba; Chang, Shang-Tzen; Kweka, Eliningaya J.The increasing status of insecticide resistant mosquitoes in sub-Saharan Africa is a threatening alert to the existing control efforts. All sibling species of An. gambiae complex have evolved insecticide resistance in wild populations for different approved classes of the insecticides currently in use in the field. An alternative compound for vector control is absolutely urgently needed. In this study, the larvicidal activity and chemical composition of the Cinnamomum osmophloeum leaf essential oils were investigated. C. osmophloeum leaf essential oils were extracted by hydrodistillation in a Clevenger-type apparatus for 6 hours, and their chemical compositions identified using GC-MS. These oils were evaluated against An. gambiae s.s. in both laboratory and semi-field situations. The WHO test procedures for monitoring larvicidal efficacy in malaria vectors were used. The composition of C. osmophloeum leaf essential oil has been found to have 11 active compounds. The most abundant compound was trans-cinnamaldehyde (70.20%) and the least abundant was caryophyllene oxide (0.08%). The larvicidal activity was found to be dosage and time dependant both in laboratory and semi-field environments with mortality ranging from 0% to 100%. The LC50 value was found to vary from 22.18 to 58.15 μg/ml in the laboratory while in semi-field environments it was 11.91 to 63.63 μg/ml. The LC90 value was found to range between 57.71 to 91.54 μg/ml in the laboratory while in semi-field environments was 52.07 to 173.77 μg/ml. Mortality ranged from 13% to 100% in the laboratory while in semi-field environments it ranged between 43% to 100% within mortality recording time intervals of 12, 24, 48, and 72 hours. The larvicidal activity shown by C. osmophloeum leaf essential oil is a promising alternative to existing larvicides or to be incorporated in integrated larval source management compounds for An. gambiae s.s control. The efficacy observed in this study is attributed to both major and minor compounds of the essential oils.Item Antiviral Activity of the Crude Extracts and Phytochemical Fractions of Aloe Secundiflora against Newcastle Disease Virus(2005) Waihenya, R. K.; Keriko, J. M.; Mtambo, M. M. A.; Nkwengulila, Gamba; Kayser, O.; Hafez, H. M.Crude extract of Aloe secundiflora (Aloeaceae), and three phytochemical (HPLC) fractions containing the major phenolic compounds were investigated for their effects on Newcastle Disease Virus (NDV) in embryonated specific pathogen free (SPF) chicken eggs. The three fractions used contained the major peaks within which the main compounds had been identified as aloenin, aloin and an aloinoside derivatives. The crude Aloe extract at 400 mg/ml exhibited antiviral effects at 100%, While 200 mg/ml resulted to 30% reduction in viral multiplication. Fraction containing aloenin (4 mg/ml = 4000 ppm) also showed 100% reduction effects of viral multiplication on NDV in nineday old embryonated chicken eggs (ECE). Fraction containing aloin (4 mg/ml = 4000 ppm) exhibited 50% reduction of viral multiplication while the fraction containing aloinside showed 70% reduction effects. The results of the study provided a justification on the ethnoveterinary use of the exudate in the prophylaxis / control of Newcastle Disease Virus.Item Assessing S. mansoni prevalence in Biomphalaria snails in the Gombe region of Western Tanzania: the importance of DNA sequence data for clarifying species identification(Parasite & Vectors, 2017) Bakuza, Jared S.; Gilespie, Robert; Nkwengulila, Gamba; Adam, Aileen; Kilbride, Elizabeth; Mable, Marble K.Item Completion of the Life Cycle of Tylodelphys Mashonense (Sudarikov, 1971) (Digenea: Diplostomidae) with DNA Barcodes and rDNA Sequences(Springer, 2015) Chibwana, F. D.; Nkwengulila, Gamba; Locke, S. A.; McLaughlin, J. D.; Marcogliese, D. J.The life cycle of Tylodelphys mashonense (Digenea: Diplostomidae), whose metacercariae occur in the cranial cavity of the widely cultivated catfish Clarias gariepinus, was resolved by the application of molecular markers. Both COI barcodes and ITS sequences obtained from diplostomid-like cercariae infecting Bulinus spp. from Mindu Dam, Morogoro, matched those acquired from metacercariae from the catfish C. gariepinus, and those from adult T. mashonense from the grey heron Ardea cinerea and the white egret Egretta alba. The success in linking the life cycle stages of T. mashonense using molecular tools highlights the usefulness of this approach in resolving the complex life cycles of digeneans in the absence of experimental establishmentItem Determinants of the Parasite Community of Clariid Fishes from Lake Victoria, Tanzania(2008) Mwita, Chacha; Nkwengulila, GambaThe factors that determine parasite assemblages among the clariid fishes of Lake Victoria, Tanzania were studied between August 2003 and February 2005. Six hundred and fifty-six fish belonging to seven species were necropsied and examined for parasites, from which 31 species of metazoan parasites were recorded. The community was dominated by the nematodes both in species and numbers. Most species were generalists with only two trematodes, Diplostomum mashonense and Tylodelphys species, being specialists of Clarias gariepinus. Ten species were considered core and predictable. Parasite species richness, number of individuals per host and Shannon –Wiener diversity indices were generally high. At the compound community level, a mean number of 7.8 parasites were shared among different species of fish and the maximum number of parasites species per fish at the infracommunity level was seven. Levels of similarity in parasite species richness at the component community level ranged from 29.6 to 61.5%. The study concludes that parasite communities in clariid fishes of Lake Victoria are structured by ecological factors. At the infracommunity level, host size, diet and vagility promoted a richer parasite community. At the compound level, two factors were crucial, namely the intermixing of the waters in the lake and the predominant and mobile C. gariepinus.Item Dhfr and dhps mutations in Plasmodium falciparum isolates in Mlandizi, Kibaha, Tanzania: association with clinical outcome(Health User's Trust Fund (HRUTF), 2007-03-02) Kidima, W.; Nkwengulila, Gamba; Premji, Z.; Malisa, A.; Mshinda, H.Sulfadoxine-pyrimethamine (SP), the current first line antimalarial drug in Tanzania, is compromised by evolution and spread of mutations in the parasite's dhfr and dhps genes. In the present study we established the baseline frequencies of Plasmodium falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) mutant genotypes and their potential for predicting the in vivo efficacy of SP in Mlandizi, Tanzania. The efficacy of SP treatment was by following 116 children with uncomplicated falciparum malaria for 14 days after treatment. Infected blood samples were collected on filter paper at days 0, 3, 7 and 14. Parasite genomic DNA was extracted and point mutations at positions 51, 59, 108 and 164 of the dhfr gene and at 581, 540 and 437 of the dhps gene were analysed by nested Polymerase Chain Reaction/ Restriction Fragment Length Polymorphism. Out of 116 children enrolled, 98 (86%) of eligible children demonstrated an adequate clinical response by day 14. There were 7.3 % early and 6.7% late therapeutic failures. At day 0, only 8.0% (4/50) the parasites showed no mutation at the dhfr locus; for dhps this was 73%. Triple mutant dhfr alleles (Ile 51, Arg 59, Asn 108) occurred in 47%, double mutant dhps (Gly 437, Glu 540) alleles in 7.9%. No mutation was detected at codon 164 of the dhfr gene. The presence of triple dhfr mutant alleles was related to clinical failure, but did not show significant association (Fisher exact test, P=0.166, OR 2.15 0.776.20). The higher rates of mutation on the dhfr do not spell a bright future for SP treatment in Tanzania. It is rational to think of an alternative first line antimalarial drug, while retaining SP for malaria intermittent treatment in pregnancy.Item Dhfr and Dhps Mutations in Plasmodium Falciparum Isolates in Mlandizi, Kibaha(2007) Kidima, W.; Nkwengulila, Gamba; Premji, Z.; Malisa, A.; Mshinda, H.Sulfadoxine-pyrimethamine (SP), the current first line antimalarial drug in Tanzania, is compromised by evolution and spread of mutations in the parasite's dhfr and dhps genes. In the present study we established the baseline frequencies of Plasmodium falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) mutant genotypes and their potential for predicting the in vivo efficacy of SP in Mlandizi, Tanzania. The efficacy of SP treatment was by following 116 children with uncomplicated falciparum malaria for 14 days after treatment. Infected blood samples were collected on filter paper at days 0, 3, 7 and 14. Parasite genomic DNA was extracted and point mutations at positions 51, 59, 108 and 164 of the dhfr gene and at 581, 540 and 437 of the dhps gene were analysed by nested Polymerase Chain Reaction/ Restriction Fragment Length Polymorphism. Out of 116 children enrolled, 98 (86%) of eligible children demonstrated an adequate clinical response by day 14. There were 7.3 % early and 6.7% late therapeutic failures. At day 0, only 8.0% (4/50) the parasites showed no mutation at the dhfr locus; for dhps this was 73%. Triple mutant dhfr alleles (Ile 51, Arg 59, Asn 108) occurred in 47%, double mutant dhps (Gly 437, Glu 540) alleles in 7.9%. No mutation was detected at codon 164 of the dhfr gene. The presence of triple dhfr mutant alleles was related to clinical failure, but did not show significant association (Fisher exact test, P=0.166, OR 2.15 0.776.20). The higher rates of mutation on the dhfr do not spell a bright future for SP treatment in Tanzania. It is rational to think of an alternative first line antimalarial drug, while retaining SP for malaria intermittent treatment in regnancy.Item Direct and Indirect Effect of Predators on Anopheles Gambiaesensu Stricto(Elsevier, 2015) Chobua, Mariam; Nkwengulila, Gamba; Mahande, Aneth M.; Mwang’onde, Beda J.; Kweka, Eliningaya J.The increased insecticides resistance by vectors and the ecological harm imposed by insecticides to beneficial organisms drawback mosquitoes chemical control efforts. Biological control would reduce insecticides tolerance and yet biodiversity friend. The predatory and non-predatory effects of Gambusia affinis and Carassius auratus on gravid Anopheles gambiae sensu strict and larvae survivorship were assessed. In determining predation rate, a single starved predator was exposed to third instar larvae of An. gambiae s.s. in different densities 20, 60 and 100. Six replicates in each of the densities for both predators, G. affinis and C. auratus, were set up. The larvae densities were monitored in every12 and 24 h. In assessing indirect effects: An. gambiae s.s. first instar larvae of three densities 20, 60 and 100 were reared in water from a predator habitat and water from non-predator habitat. Larvae were monitored until they emerged to adults where larval survivorship and sex ratio (Female to total emerged mosquitoes) of the emerged adult from both water habitats were determined. Oviposition preference: twenty gravid females of An. gambiae s.s. were provided with three oviposition choices, one containing water from predator habitat without a predator, the second with water from a predator with a predator and the third with water from non-predatory habitat. The number of eggs laid on each container was counted daily. There were 20 replicates for each predator, G. affinis and C. auratus. Survivorship of An. gambiae s.s. larvae reared in water from non-predator habitat was higher than those reared in water from the predator habitats. Many males emerged in water from non-predatory water habitats while more females emerged from predator's habitats water. More eggs laid in tap water than in water from predator habitat and water from predator habitat with live predator. In 24 h, a starved C. auratus and G. affinis were able to consume 100% of the 3rd instar larvae. The findings from this study suggest that G. affinis and C. auratus may be useful in regulating mosquito populations in favour of beneficial insects. However, a small scale trial shall be needed in complex food chain system to ascertain the observed predation and kairomones effects.Item Distribution and population size of Glossina fuscipes fuscipes (tsetse flies) along the Lake Victoria, for trypanosomiasis management in Tanzania(2015) Manangwa, O.; Ouma, J. O.; Malele, I.; Msangi, A.; Mramba, F.; Nkwengulila, GambaGlossina fuscipes fuscipes is among the important tsetse species of economic importance in Tanzania. The fly has a wide geographic distribution in sub-Saharan Africa. The information on distribution and population size of any fly specie is crucial when planning control strategies against tsetse as it helps to tell where to start traps deployment as well as estimate of the number of traps to be deployed on a particular area. Population size and distribution estimate studies were carried out along the shores of Lake Victoria in Tanzania. The study involved Kirongwe, Masonga, Rasi Nyabero and Tobwe River villages in Rorya district, Msozi village in Ukerewe district and Kemondo village in Bukoba district. The results showed that the species is widely distributed along the shores of Lake Victoria. It extends from the north east of the Lake in Kirongwe village in Rorya district that borders Kenya to Kinase village that border Musoma district. It further extends to the north west of the Lake Victoria to Rubafu Ruina villages that border Uganda and also in Kemondo areas, just close to Bukoba town. Flies were also found in small visited Islands in Rorya district namely, Bugambwa and Ngonshe in Suba division. The biggest, Ukerewe Island was also infested with G. f. fuscipes in Msozi village and Namabugo village near Nansio town. Masonga had the highest fly abundance of 9.10 ± 0.501FTD (fly per trap per day) compared to other villages while Tobwe River had the least abundance of 0.94 ± 0.501 FTD during the dry season. A similar trend was also observed for the wet season, Masonga had the highest abundance of 6.40 ± 0.501FTD and Tobwe River had the least abundance of 1.63 ± 0.501. Based on the results of this study, if control activities are to be undertaken, more traps and targets are needed in Masonga and Rasi Nyabero vilages than in Kirongwe and Tobwe River. Age structure results elucidate that many flies caught were young flies aging 0 to 14 days and few flies were in wing category 4, 5 and 6. The control technology to be used will be dealing with young generation of flies which are mainly tenerals and looking for mating thus can easily succumb to baits (traps and targets) if effectively executed. There was significant variation of traps performance between different study sites. Further research is required to clarify the cause of this variation with locations.Item Diversity, Spatial and Temporal Abundance of Anopheles Gambiae Complex in the Rufiji River Basin, South-Eastern Tanzania(2010) Nkwengulila, Gamba; Magesa, S. M.; Abdulla, Salim; Kigadye, E. S. P.The Anopheles gambiae complex contains the most efficient malaria vectors in the world. Identification of the species and the concomitant distribution are vital for effective malaria control. The objective of the study was to establish the diversity, spatial and seasonal abundance of malaria vectors in the Rufiji River Basin in Tanzania and the implications on malaria vector control. Mosquitoes were collected using CDC light-traps. Anopheles mosquitoes were identified by conventional keys. Anopheles gambiae complex were speciated using standard PCR method. Of the 562 specimens analysed by PCR 69% produced fragments equivalent to An. gambiae s.s. (390 bp), 23% equivalent to An. arabiensis (315bp), and 7% as An. merus (464 bp). An. gambiae s.s. and An. merus were more abundant on the plateau than on the flood plain (Fisher’s exact test, P< 0001), whereas An. arabiensis was equally abundant between the two sites (Fisher’s exact test, P=1656). The density of the three sibling species of An. gambiae complex also varied with the seasons. An. gambiae s.s. and An. arabiensis were most predominant species during the start of the rainy season, but as season progresses, An. gambiae s.s. predominated. An. merus was only recorded during the short rainy season. In conclusion, both An. gambiae s.s., An. arabiensis and An.merus are malaria vectors in the Rufiji River basin and that An. merus is recorded for the first time in the south-eastern coast of Tanzania. These findings are important in the planning and implementation of malaria vector control activities in the Rufiji River basin, south-eastern Tanzania.Item Ecologists Can Enable Communities to Implement Malaria Vector Control in Africa(BioMed Central, 2006) Mukabana, Richard W.; Kannady, Khadija; Kiama, Michael G.; Ijumba, Jasper N.; Mathenge, Evan M.; Kiche, Ibrahim; Nkwengulila, Gamba; Mboera, Leonard; Mtasiwa, Deo; Yamagata, Yoichi; Schayk, Ingeborg van; Knols, Bart G. J.; Lindsay, Steven W.; Castro, Marcia C.; Mshinda, Hassan; Tanner, Marcel; Fillinger, Ulrike; Killeen, Gerry F.Integrated vector management (IVM) for malaria control requires ecological skills that are very scarce and rarely applied in Africa today. Partnerships between communities and academic ecologists can address this capacity deficit, modernize the evidence base for such approaches and enable future scale up. Community-based IVM programmes were initiated in two contrasting settings. On Rusinga Island, Western Kenya, community outreach to a marginalized rural community was achieved by University of Nairobi through a community-based organization. In Dar es Salaam, Tanzania, Ilala Municipality established an IVM programme at grassroots level, which was subsequently upgraded and expanded into a pilot scale Urban Malaria Control Programme with support from national academic institutes. Both programmes now access relevant expertise, funding and policy makers while the academic partners benefit from direct experience of community-based implementation and operational research opportunities. The communities now access up-to-date malaria-related knowledge and skills for translation into local action. Similarly, the academic partners have acquired better understanding of community needs and how to address the Until sufficient evidence is provided, community-based IVM remains an operational research activity. Researchers can never directly support every community in Africa so community-based IVM strategies and tactics will need to be incorporated into undergraduate teaching programmes to generate sufficient numbers of practitioners for national scale programmes. Academic ecologists at African institutions are uniquely positioned to enable the application of practical environmental and entomological skills for malaria control by communities at grassroots level and should be supported to fulfil this neglected role.Item Effect of Larval Crowding on Mating Competitiveness of Anopheles Gambiae Mosquitoes(BioMed Central, 2005) Ng'habi, Kija R.; John, Bernadette; Nkwengulila, Gamba; Knols, Bart G. J.; Killeen, Gerry F.; Ferguson, Heather M.The success of sterile or transgenic Anopheles for malaria control depends on their mating competitiveness within wild populations. Current evidence suggests that transgenic mosquitoes have reduced fitness. One means of compensating for this fitness deficit would be to identify environmental conditions that increase their mating competitiveness, and incorporate them into laboratory rearing regimes. Anopheles gambiae larvae were allocated to three crowding treatments with the same food input per larva. Emerged males were competed against one another for access to females, and their corresponding longevity and energetic reserves measured. Males from the low-crowding treatment were much more likely to acquire the first mating. They won the first female approximately 11 times more often than those from the highcrowding treatment (Odds ratio = 11.17) and four times more often than those from the mediumcrowding treatment (Odds ratio = 3.51). However, there was no overall difference in the total number of matings acquired by males from different treatments (p = 0.08). The survival of males from the low crowding treatment was lower than those from other treatments. The body size and teneral reserves of adult males did not differ between crowding treatments, but larger males were more likely to acquire mates than small individuals. Larval crowding and body size have strong, independent effects on the mating competitiveness of adult male An. gambiae. Thus manipulation of larval crowding during mass rearing could provide a simple technique for boosting the competitiveness of sterile or transgenic male mosquitoes prior to releaseItem Efficacy of crude extract of Aloe secundiflora against Salmonella gallinarum in experimentally infected free-range chickens in Tanzania(Elsevier Ireland Ltd, 2002) Waihenya, R.K.; Mtambo, M.M.A.; Nkwengulila, Gamba; Minga, U.M.The ethnoveterinary use of Aloe species extract in free-range local chickens against fowl typhoid was investigated. Five-months-old local chickens, free of antibodies against fowl typhoid were used. The chickens were randomly assorted into five groups including pretreated and infected (G1, n=21), infected and untreated (G2, n=21), infected and treated (G3, n=21), untreated and uninfected (G4, n=10) and treated uninfected (G5, n=10). Groups 1, 2 and 3 were inoculated with 5.0×108 c.f.u/ml of Salmonella gallinarum, following which the chickens were monitored for 15 days. There was a delay on the occurrence of the clinical signs and reduced severity of the disease in the Aloe treated chickens (G1 and G3). The mortality rates were 23.8% (5/21) in G1 (pretreated and infected), 42.8% (9/21) in G2 (infected and untreated) and 14.2% (3/21) in G3 (infected and treated). Antibody levels were raised among the infected and untreated group (G2) while they remained relatively low in the Aloe treated groups (G1 and G3). However, there was a sharp increase in the levels of interleukin 6 (IL-6) in the Aloe treated groups (G1 and G3) as compared to the untreated group (G2) until day 9 post-infection. The results of this work indicate that the extract of Aloe secundiflora may be used in the control of fowl typhoid in chickens. Studies to determine the active ingredients of the plant extract are in progressItem Environmental Contamination by Taenia Eggs in Iringa Rural District, Tanzania(2013) Mwita, Chacha J.; Tesha, Julius; Nkwengulila, GambaCysticercosis and Taeniosis are global health problems with impacts on human beings and the development of the livestock industry. This study tested the presence of Taenia eggs in the soil of two villages in Iringa rural district, Tanzania. No recognizable Taenia egg was found, though those found were difficult to identify due to absorption of the flotation fluid which made them dark with difficulties to see the innermost structures. In view of their sizes (30 - 40 microns in diameter) these eggs were considered to be of Taenia spp. In addition, eggs from four geo-helminth species were identified namely; Ascaris lumbricoides, Schistosoma mansoni, Strongyloides stercoralis and Trichuris trichiura eggs. The frequency of T. trichiura was 81.97%, Ascaris lumbricoides was 8.2%, unidentified eggs 6.01%, Strongyloides stercoralis 3.3% and Schistosoma mansoni was 0.5%. The most contaminated sites were backyard with a prevalence of 30.1% followed by west disposal site (WDS) 25.7%, open defaecation area (ODA) 24.0% and the least was toilet 20.2%. About 31 (31%) samples had no eggs. The findings revealed that the environment of Izazi village was more contaminated by geohelminth eggs (19.4%) than that of Migoli village (12.1%) and that higher moisture content in soils favors the growth, development, spread and transmission of geo-helminth eggs.Item Epidemiology and Taxonomy of Diplostomum Species (Trematoda: Diplostomatidae) Infecting Fish of Llyn Tegid, North Wales and the Ruvu Basin, Tanzania.(1995) Nkwengulila, GambaThis study investigated the epidemiology and taxonomy of Diplostomuni species in the deeper parts of the eye (DPE) of roach Rutilus rutilus (L. ), perch Perca fluviatilis L., ruffe Gymnocephalus cernua (L. ) and gwyniad Coregonus lavaretus (L. ) at Llyn Tegid, North Wales, and in the cranium of catfish Clarias gariepinus (Burchell, 1822) and the vitreous humour of Oreochromis species at Mindu dam and river Ruvu, Tanzania. At Llyn Tegid, two species of Diplostomum metacercariae, large and small forms, coexisted in DPE of perch, ruffe and gwyniad but only one, large forms, occurred in roach. Large forms were distinguished by their large size, oval body tapering at both ends and pseudosuckers at the level of the oral sucker. Small forms were distinguished by their smaller size, oval body with parallel sides and pseudosuckers occurring below the level of the oral sucker. The taxonomy of the two forms was not resolved even after obtaining adults from chickens. Tentatively, small forms keyed close to D. gasterostei Williams, 1966 and large forms to D. volvens Nordmann, 1832. Inadequate identification manuals and remarkable similarity between Diplostonlum species confounded identification. Mean intensity of metacercariae was highest in ruffe and lowest in perch and increased with host size in all hosts. Factors responsible for differences in mean intensity between hosts were discussed. There was no seasonality of occurrence. Recruitment occurred from May - November correlating with water temperatures. Immature metacercariae occurred throughout the period of investigation. Metacercariae were overdispersed in all three hosts. At Mindu and Ruvu two species were present, D. sp. X (1,2) in the cranium of catfish and D. sp. Y in the vitreous humour of Oreochromis sp. D. sp. X (1,2) were distinguished by their elongate body, oval calcareous corpuscles and long hindbody. D. sp. Y were distinguished by a vestigial ventral sucker, glandular Brandes organ, short hindbody and spherical calcareous corpuscles. D. sp. X (1,2) were identified as D. mashonense Beverley - Burton, 1963. Adults cultured in chickens confirmed identification. D. sp. X (1,2) developed to ovigerous adults within 24h. Percent recovery of adults from chickens declined with days p. i. Miracidia developed in eggs in six days. D. sp. Y is considered an undescribed taxon. Prevalence and mean intensity of D. sp. Y in Oreochromis sp. were low and did not fluctuate seasonally. Prevalence of D. mashonense in catfish was similar at Mindu and Ruvu and exhibited no seasonal fluctuations. Mean intensity of D. mashonense in catfish of Mindu fluctuated seasonally, increased with host size and was higher than in catfish from Ruvu. Causes of high intensity and seasonal changes at Mindu were discussed. D. mashonense was overdispersed in catfish at both localities but only data from Mindu fitted the negative binomial model. Small samples and the dynamism of forces creating overdispersion were considered responsible for the situation at Ruvu. Using SEM ciliated-pit and dome-shaped papillae were observed on the surface of metacercariae and adults of D. mashonense . Ciliated-pit papillae occurred only on metacercariae. Dome-shaped papillae, in adults and metacercariae, were aggregated on suckers, excretory and genital atria. Spines were multipointed in adults but single pointed in metacercariae.Item Estimating the prevalence and intensity of Schistosoma mansoni infection among rural communities in Western Tanzania: The influence of sampling strategy and statistical approach(PLOS Neglected Tropical Diseases, 2017-09-21) Bakuza, Jared S.; Nkwengulila, Gamba; Denwood, Matthew J.; Mable, Barbara KBackground Schistosoma mansoni is a parasite of major public health importance in developing countries, where it causes a neglected tropical disease known as intestinal schistosomiasis. However, the distribution of the parasite within many endemic regions is currently unknown, which hinders effective control. The purpose of this study was to characterize the prevalence and intensity of infection of S. mansoni in a remote area of western Tanzania. Methodology/Principal findings Stool samples were collected from 192 children and 147 adults residing in Gombe National Park and four nearby villages. Children were actively sampled in local schools, and adults were sampled passively by voluntary presentation at the local health clinics. The two datasets were therefore analysed separately. Faecal worm egg count (FWEC) data were analysed using negative binomial and zero-inflated negative binomial (ZINB) models with explanatory variables of site, sex, and age. The ZINB models indicated that a substantial proportion of the observed zero FWEC reflected a failure to detect eggs in truly infected individuals, meaning that the estimated true prevalence was much higher than the apparent prevalence as calculated based on the simple proportion of non-zero FWEC. For the passively sampled data from adults, the data were consistent with close to 100% true prevalence of infection. Both the prevalence and intensity of infection differed significantly between sites, but there were no significant associations with sex or age. Conclusions/Significance Overall, our data suggest a more widespread distribution of S. mansoni in this part of Tanzania than was previously thought. The apparent prevalence estimates substantially underestimated the true prevalence as determined by the ZINB models, and the two types of sampling strategies also resulted in differing conclusions regarding prevalence of infection. We therefore recommend that future surveillance programmes designed to assess risk factors should use active sampling whenever possible, in order to avoid the self-selection bias associated with passive sampling.Item Evaluation of Repellents Efficacy against Anopheles Gambiae s.s.; An Anthropophilic Malaria Vector(2015) Katunzi, Gerald; Munga, Stephen; Nkwengulila, Gamba; Kweka, Eliningaya J.; Matias, Jonathan R.; Godfrey, Gilbert M.Reduction of human-vector contact is of epidemiological importance in malaria control. Repellents can be used to complement the existing intervention tools against malaria vectors. Thus, evaluation of efficacy of additional mosquito repellents and /or attractants is of great significance for personal protection tools against malaria vectors. This study evaluated the repellence efficacy of menthol-propylene-glycol-carbonate (MR08) and Lemon grass (LG) against Anopheles gambiae. Experiments were performed in a room which was 7.8 meters by 3.9 meters in dimension. Three experimental set ups were performed, i) comparison of 10 hours worn sock and unworn sock; ii) comparison of 10 hours worn sock treated with MR08 against worn sock alone, and iii) comparison of 10 hours worn sock treated with LG against worn sock alone. CDC miniature light traps were used to evaluate the recovery of released mosquitoes using both repellents and attractants. After initial trials, a concentration of 500 ppm was selected for all repellents. Among 1800 mosquitoes released into the experimental room, 1230 were recovered by CDC light traps while the remaining 570 were found within the experimental room. Among those collected by light traps, 1185 were collected by traps with worn sock alone. A worn sock treated with either MR08 or Lemon grass significantly repelled An.gambiae compared to worn sock alone. The findings of this study demonstrate that MR08 and lemon grass have inhibition efficiency against mosquito stings but further field evaluations are required for observed findings against wild populations of An.gambiae at lower Moshi using slow release methodItem Evaluation of the Efficacy of the Crude Extract of Aloe Secundiflora in Chickens Experimentally Infected with Newcastle Disease Virus(Elsevier, 2002) Waihenya, R.K.; Mtambob, M.M.A.; Nkwengulila, GambaTwo replicate experiments were carried out to verify the efficacy of Aloe species (Aloaceae) as used for the control of Newcastle disease (ND) in rural poultry in free-range systems among several communities in Tanzania. Four months old local chickens free of Newcastle disease antibodies were used. Following inoculation with ND virus, body weights, clinical signs, antibody levels and mortality were monitored. Results showed that there was reduced mortality rate and the severity of clinical signs during the acute phase of the infection in Aloe treated chickens compared with the non-treated ones. However, there was no significant effect of the Aloe on the antibody levels that were attributed to the recovery of the surviving chickens. The findings of this study suggest that Aloe secundiflora could be a potential candidate on the management of Newcastle disease in chickens. Further studies are in progress to identify the active ingredients of A. secundiflora against Newcastle disease virus.Item Extent of Morbidity Associated with Schistosomiasis Infection in Malawi: A Review Paper(BioMed Central, 2015) Mtethiwa, Austin H. N.; Nkwengulila, Gamba; Bakuza, Jared S.; Sikawa, Daniel; Kazembe, AbigailData on the extent of the burden due to schistosomiasis is sparse in most Sub-Saharan African countries. However, this data is crucial for triggering medical attention. A review of extent of morbidity and determinants associated with schistosomiasis in Malawi was therefore conducted to quantify the infection in order to concretise the need for medical intervention. A systematic and traditional search strategy was used to find literature for the review, whilst exclusion and inclusion criteria were used to identify appropriate articles. Logistic regression curves of epidemiological model Y = (a + bxc )/(1 + bxc ) and the recommendation that schistosomiasis prevalence can be used to estimate morbidity were employed to quantify morbidity at various infection stages. Morbidity was quantified as a direct proportion of the population and the respective national schistosomiasis prevalence. Findings showed that both S. mansoni and S. haematobium are present in Malawi with the latter highly prevalent (50%). Furthermore, out of the estimated population of 16,829 million, approximately 8.4 million have schistosomiasis, with about 4.4 million of these aged 18 years and below. The most frequent manifestation is Katayama syndrome, while ascites is the lowest, impacting about 3.0 million and 960 individuals, respectively. Localised studies on association of schistosomiasis infection to risk factors such as occupation, age and gender found odds ratio (OR) ranging from 1.29 to 5.37. Morbidity due to schistosomiasis is high in Malawi. It is therefore recommended that a more detailed study on the determinants of high schistosomiasis and re-evaluation of the current control measures be conducted if the current morbidity statistics are to be remarkably reduced.Item Extent of morbidity associated with schistosomiasis infection in Malawi: a review paper.(Infectious Diseases of Poverty, 2015-05) Mtethiwa, Austin; Nkwengulila, Gamba; Sikawa, D.; Kazembe, A.Data on the extent of the burden due to schistosomiasis is sparse in most Sub-Saharan African countries. However, this data is crucial for triggering medical attention. A review of extent of morbidity and determinants associated with schistosomiasis in Malawi was therefore conducted to quantify the infection in order to concretise the need for medical intervention. A systematic and traditional search strategy was used to find literature for the review, whilst exclusion and inclusion criteria were used to identify appropriate articles. Logistic regression curves of epidemiological model Y = (a + bxc)/(1 + bxc) and the recommendation that schistosomiasis prevalence can be used to estimate morbidity were employed to quantify morbidity at various infection stages. Morbidity was quantified as a direct proportion of the population and the respective national schistosomiasis prevalence. Findings showed that both S. mansoni and S. haematobium are present in Malawi with the latter highly prevalent (50%). Furthermore, out of the estimated population of 16,829 million, approximately 8.4 million have schistosomiasis, with about 4.4 million of these aged 18 years and below. The most frequent manifestation is Katayama syndrome, while ascites is the lowest, impacting about 3.0 million and 960 individuals, respectively. Localised studies on association of schistosomiasis infection to risk factors such as occupation, age and gender found odds ratio (OR) ranging from 1.29 to 5.37. Morbidity due to schistosomiasis is high in Malawi. It is therefore recommended that a more detailed study on the determinants of high schistosomiasis and re-evaluation of the current control measures be conducted if the current morbidity statistics are to be remarkably reduced