Browsing by Author "Nnko, Happiness"

Now showing 1 - 3 of 3

Assessment of pastoralists’ vulnerability to trypanosomiasis and effects of climate on tsetse and trypanosomes distribution in Tanzania’s Maasai steppe
(NM-AIST, 2017-12) Nnko, Happiness
For decades, pastoralists have had their adaptation strategies that enable them to thrive in harsh environments. However, changing climate and land management regimes, coupled with under-investments in pastoral areas, threaten to overwhelm pastoralists’ traditional adaptation methods. This could potentially increase vulnerability of pastoral communities to multiple stressors, including trypanosomiasis. Trypanosomiasis is caused by a parasitic protozoan of Trypanosoma spp where tsetse flies are the main vector. Trypanosomiasis is a neglected tropical disease, yet a disease of public health and socio-economic concern. It exacerbates economic hardships due to loss of livestock or through additional costs needed to control and treat the disease. Despite these concerns, information about where and when to expect high burden of tsetse flies and trypanosomes remain limited, and control strategies, if offered, are often ineffective. This study therefore assessed pastoralists’ vulnerability to trypanosomiasis, seasonality of tsetse fly abundance, prevalence of trypanosome infections in the vector, and potential impacts of climate change on tsetse fly distribution. The study incorporated social and ecological analytical techniques including ArcGIS 10.4, polymerase chain reaction (PCR) and species distribution modelling (SDM). Emboreet and Loibor-Sireet Wards in Simanjiro district were identified as the most vulnerable locations to trypanosomiasis. Three tsetse fly species (Glossina m. morsitans, Glossina pallidipes and Glossina swynnertoni) and three trypanosome species (T.vivax, T.congolense and T. brucei) were found in the study area. Tsetse fly relative abundance and trypanosome prevalence peaked in July and October, respectively. Maximum and minimum temperature negatively affected abundance of G. m. morsitans and G. swynnertoni, respectively. Trypanosome prevalence was negatively correlated with tsetse abundance but positively correlated with temperature. The climate tsetse fly relationships were used in the SDM to show that by the year 2050, the habitable area of G. m. morsitans, G. pallidipes and G. swynnertoni may decrease to 23.13%, 12.9% and 22.8% of current suitable habitat (19 224.58 km2 , 7113.37 km2 and 32 335.27 km2 ), respectively in the study area. These results provide useful information to inform communities, health and livestock development sectors and tsetse fly control units on where and when to expect the highest risk of trypanosomiasis infection in the Maasai Steppe and plan accordingly. ii Keywords: Pastoralist, vulnerability, trypanosomiasis, adaptation, tsetse, trypanosome prevalence, seasonality, SDM, Maasai Steppe, Tanzania
Pastoralists’ Vulnerability to Trypanosomiasis in Maasai Steppe
(Springer New York LLC, 2017-09-04) Nnko, Happiness; Gwakisa, Paul; Ngonyoka, Anibariki; Saigilu, Meshack; Ole-Neselle, Moses; Kisoka, William; Sindato, Calvin; Estes, Anna
Trypanosomiasis is a neglected tropical disease of both livestock and humans. Although pastoral communities of the Maasai Steppe have been able to adapt to trypanosomiasis in the past, their traditional strategies are now constrained by changes in climate and land regimes that affect their ability to move with their herds and continually shape the communities’ vulnerability to trypanosomiasis. Despite these constraints, information on communities’ vulnerability and adaptive capacity to trypanosomiasis is limited. A cross-sectional study was therefore conducted in Simanjiro and Monduli districts of the Maasai Steppe to establish pastoralists’ vulnerability to animal trypanosomiasis and factors that determined their adaptation strategies. A weighted overlay approach in ArcGIS 10.4 was used to analyze vulnerability levels while binomial and multinomial logistic regressions in R 3.3.2 were used to analyze the determinants of adaptation. Simanjiro district was the most vulnerable to trypanosomiasis. The majority (87.5%, n = 136) of the respondents were aware of trypanosomiasis in animals, but only 7.4% (n = 136) knew about the human form of the disease. Reported impacts of animal trypanosomiasis were low milk production (95.6%, n = 136), death of livestock (96.8%, n = 136) and emaciation of animals (99.9%, n = 136). Crop farming was the most frequently reported animal trypanosomiasis adaptation strategy (66%, n = 136). At a 95% confidence interval, accessibility to livestock extension services (β = 7.61, SE = 3.28, df = 135, P = 0.02), years of livestock keeping experience (β = 6.17, SE = 1.95, df = 135, P = 0.001), number of cattle owned (β = 5.85, SE = 2.70, df = 135, P = 0.03) and membership in associations (β = − 4.11, SE = 1.79, df = 135, P = 0.02) had a significant impact on the probability of adapting to animal trypanosomiasis.
Patterns of tsetse abundance and trypanosome infection rates among habitats of surveyed villages in Maasai steppe of northern Tanzania
(BioMed Central Ltd., 2017-09-04) Ngonyoka, Anibariki; Gwakisa, Paul; Estes, Anna; Salekwa, Linda; Nnko, Happiness; Hudson, Peter; Cattadori, Isabella
Background: Changes of land cover modify the characteristics of habitat, host-vector interaction and consequently infection rates of disease causing agents. In this paper, we report variations in tsetse distribution patterns, abundance and infection rates in relation to habitat types and age in the Maasai Steppe of northern Tanzania. In Africa, Tsetse-transmitted trypanosomiasis negatively impacted human life where about 40 million people are at risk of contracting the disease with dramatic socio-economical consequences, for instance, loss of livestock, animal productivity, and manpower. Methods: We trapped tsetse flies in dry and wet seasons between October 2014 and May 2015 in selected habitats across four villages: Emboreet, Loiborsireet, Kimotorok and Oltukai adjacent to protected areas. Data collected include number and species of tsetse flies caught in baited traps, PCR identification of trypanosome species and extraction of monitored Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectrometer (MODIS). Results: Our findings demonstrate the variation of tsetse fly species abundance and infection rates among habitats in surveyed villages in relation to NDVI and host abundance. Results have shown higher tsetse fly abundance in Acacia-swampy ecotone and riverine habitats for Emboreet and other villages, respectively. Tsetse abundance was inconsistent among habitats in different villages. Emboreet was highly infested with Glossina swynnertoni (68%) in ecotone and swampy habitats followed by G. morsitans (28%) and G. pallidipes (4%) in riverine habitat. In the remaining villages, the dominant tsetse fly species by 95% was G. pallidipes in all habitats. Trypanosoma vivax was the most prevalent species in all infected flies (95%) with few observations of co-infections (with T. congolense or T. brucei). Conclusions: The findings of this study provide a framework to mapping hotspots of tsetse infestation and trypanosomiasis infection and enhance the communities to plan for effective control of trypanosomiasis.