Spatial Analysis of Temporal Changes in the Pandemic of Severe Cassava Mosaic Disease in Northwestern Tanzania

Published online: 8 Sept 2017To improve understanding of the dynamics of the cassava mosaic disease (CMD) pandemic front, geospatial approaches were applied to the analysis of 3 years’ data obtained from a 2-by-2° (approximately 222-by-222 km) area of northwestern Tanzania. In total, 80 farmers’ fields were assessed in each of 2009, 2010, and 2011, with 20 evenly distributed fields per 1-by-1° quadrant. CMD-associated variables (CMD incidence, CMD severity, vector-borne CMD infection, and vector abundance) increased in magnitude from 2009 to 2010 but showed little change from 2010 to 2011. Increases occurred primarily in the two westernmost quadrants of the study area. A pandemic “front” was defined by determining the values of CMD incidence and whitefly abundance where predicted disease gradients were greatest. The pandemic-associated virus (East African cassava mosaic virus-Uganda) and vector genotype (Bemisia tabaci sub-Saharan Africa 1–subgroup 1) were both present within the area bounded by the CMD incidence front but both also occurred ahead of the front. The average speed and direction of movement of the CMD incidence front (22.9 km/year; southeast) and whitefly abundance front (46.6 km/year; southeast) were calculated, and production losses due to CMD were estimated to range from US$4.3 million to 12.2 million

Survey of physicochemical characteristics and microbial contamination in selected food locally vended in Morogoro Municipality, Tanzania

Biomed central Research notel 2015Background: Raw milk, raw fruit juice and raw fish are enriched with essential nutrients for human diet but are prone to microbial contamination along the value chain. This cross sectional study was conducted to assess physicochemical characteristics and microbial quality of raw milk, fruit juice and fish from food vendors in Morogoro Municipality, Tanzania. The physicochemical assessment of food samples was done by smell, colour, presence of debris, turbidity, consistence, pH and clot on alcohol test. Hygiene of food containers, personnel and the vending environment was also assessed. Qualitative and quantitative microbial assessment of food was done using standard laboratory protocols as described by Tanzania Bureau of Standards and International Systems of Standards. Results: Raw milk sold in Morogoro was of poor quality since was adulterated with water, contained sediments and clotted on alcohol test. Up to 63 % of the milk samples were contaminated with Escherichia coli and 60 % had higher total viable count (TVC) than the recommended values. Raw fruit juice was stored in dirty containers and sold under unhygienic environment. Seventy-three percent of juice samples had TVC beyond the recommendations while E. coli contamination rate was 63.3 %. The raw fish samples had started spoiling as depicted through sensory evaluation. E. coli contamination rate was 55 % and that of Campylobacter jejuni was 0.5 %. The mean TVC of raw fish was 8.1 (Log cfu/g) and 96.2 % of the fish samples had TVC beyond the recommended limits of 5.0 Log cfu/g. Conclusions: The physicochemical characteristics of food vended in Morogoro Municipality were of poor quality. The food had high bacterial contaminations. This situation poses health risks to the public and losses to food vendors due to spoilage. Stakeholders in food value chain should be educated on safe production and good hygienic practices. Routine quality and safety assessment of locally vended food, inspection of selling premises and regular health checkup of the personnel involved in food vending industry should be instituted

Genetic diversity study of Vanilla planifolia G. Jackson, syn. V. fragrans crop grown in Tanzania using molecular techniques

Natural vanilla (Vanilla planifolia G. Jackson, syn. V. fragrans) is native to the tropic forest of Mexico. It is now cultivated in humid tropical areas of Africa, America, Asia and Australia continents. In Tanzania it had been cultivated since 1940s in Kagera region but decline in coffee prices in the world market in the 1990s resulted into more cultivation of the vanilla crop as an alternate crop in Kagera and Kilimanjaro regions. Vanilla which had a remarkable high price compared to coffee was consequently spread and grown in Tanga, Morogoro regions and Zanzibar Island. A study was undertaken to identify cultivars and examine the extent of genetic diversity of Vanilla planifolia using molecular technique. A total of 126 samples were randomly taken from Bulinda, Bakabuye and Kibona villages in Kagera Region, Mkunazini and Donge village in Zanzibar Island and Mudio and Kidia villages in Kilimanjaro Region. The deoxyribonucleic acid (DNA) extraction method that was used in this research was the Dellaporta protocol. DNA quantification was done by comparing band intensity of different concentrations of standard genomic DNA markers using agarose gel electrophoresis. For the optimization of PCR, three different components; dNTPs, Taq DNA polymerase and MgCl2 were tested in different combinations.Ten primers were selected for the Random Amplified Polymorphic DNA (RAPD) reactions. The results revealed genetic distances of 0.667, 0.705 and 0.805 for Kagera, Kilimanjaro and Zanzibar respectively for intra population diversity and 1.28 for interpopulation diversity. This indicates a narrow genetic diversity. Similarly altogether the 126 cultivars included in this study generated 53 bands of which only 27 were polymorphic this indicates a low level polymorphism. The fact that the vanilla cultivars from Kilimanjaro and Kagera did not markedly diverge genetically from the vanilla cultivars in Zanzibar island suggests a narrow genetic diversity of populations and probably present cultivars have been derived from common source parents and maintained over several decades. Exchange of cultivars between plantations and seedling selection may also have played a role.SUA -PANTI

Genetic diversity study of Vanilla planifolia G. Jackson, syn. V. fragrans crop grown in Tanzania using molecular techniques

Natural vanilla (Vanilla planifolia G. Jackson, syn. V. fragrans) is native to the tropic forest of Mexico. It is now cultivated in humid tropical areas of Africa, America, Asia and Australia continents. In Tanzania it had been cultivated since 1940s in Kagera region but decline in coffee prices in the world market in the 1990s resulted into more cultivation of the vanilla crop as an alternate crop in Kagera and Kilimanjaro regions. Vanilla which had a remarkable high price compared to coffee was consequently spread and grown in Tanga, Morogoro regions and Zanzibar Island. A study was undertaken to identify cultivars and examine the extent of genetic diversity of Vanilla planifolia using molecular technique. A total of 126 samples were randomly taken from Bulinda, Bakabuye and Kibona villages in Kagera Region, Mkunazini and Donge village in Zanzibar Island and Mudio and Kidia villages in Kilimanjaro Region. The deoxyribonucleic acid (DNA) extraction method that was used in this research was the Dellaporta protocol. DNA quantification was done by comparing band intensity of different concentrations of standard genomic DNA markers using agarose gel electrophoresis. For the optimization of PCR, three different components; dNTPs, Taq DNA polymerase and MgCl2 were tested in different combinations.Ten primers were selected for the Random Amplified Polymorphic DNA (RAPD) reactions. The results revealed genetic distances of 0.667, 0.705 and 0.805 for Kagera, Kilimanjaro and Zanzibar respectively for intra population diversity and 1.28 for interpopulation diversity. This indicates a narrow genetic diversity. Similarly altogether the 126 cultivars included in this study generated 53 bands of which only 27 were polymorphic this indicates a low level polymorphism. The fact that the vanilla cultivars from Kilimanjaro and Kagera did not markedly diverge genetically from the vanilla cultivars in Zanzibar island suggests a narrow genetic diversity of populations and probably present cultivars have been derived from common source parents and maintained over several decades. Exchange of cultivars between plantations and seedling selection may also have played a role.SUA -PANTI