Genetically distinct strains of Cassava brown streak virus in the Lake Victoria basin and the Indian Ocean coastal area of East Africa

2009 ◽  
Vol 154 (2) ◽  
pp. 353-359 ◽  
Author(s):  
D. R. Mbanzibwa ◽  
Y. P. Tian ◽  
A. K. Tugume ◽  
S. B. Mukasa ◽  
F. Tairo ◽  
...  
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
Coastal Area ◽  
Lake Victoria ◽  
Streak Virus ◽  
Lake Victoria Basin ◽  
Cassava Brown Streak Virus ◽  
The Indian Ocean ◽  
Brown Streak

Cassava brown streak virus. [Distribution map].

1968 ◽  
Author(s):  
Keyword(s):  
East Africa ◽  
Geographical Distribution ◽  
Manihot Esculenta ◽  
Streak Virus ◽  
Distribution Map ◽  
Cassava Brown Streak Virus ◽  
Virus Distribution ◽  
New Distribution ◽  
Brown Streak

Abstract A new distribution map is provided for Cassava brown streak virus Storey. Hosts: Cassava (Manihot esculenta). Information is given on the geographical distribution in AFRICA, East Africa, Malawi, Mozambique, Rhodesia, Tanzania (Tanganyika), Uganda.

scholarly journals Customization and Validation of a Regional Climate Model Using Satellite Data Over East Africa

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 317
Author(s):  
Masilin Gudoshava ◽  
Fredrick H. M. Semazzi
Keyword(s):  
Indian Ocean ◽  
Surface Temperature ◽  
East Africa ◽  
Climate Model ◽  
Lake Victoria ◽  
Regional Climate ◽  
Sea Surface ◽  
Modes Of Variability ◽  
The Indian Ocean ◽  
Short Rains

This study focused on the customization of the fourth generation International Center for Theoretical Physics Regional Climate Model version 4.4 and its ability to reproduce the mean climate and most dominant modes of variability over East Africa. The simulations were performed at a spatial resolution of 25 km for the period 1998–2013. The model was driven by ERA-Interim reanalysis. The customization focus was on cumulus and microphysics schemes during the Short Rains for the year 2000. The best physics combinations were then utilized for the validation studies. The East Africa region and Lake Victoria Basin region are adapted to carry out empirical orthogonal function analysis, during the Short and Long Rains. Tropical Rainfall Measuring Mission data was utilized in the validation of the model. The first mode of variability from the model and observational data during the Short Rains was associated with the warming of the Pacific Ocean and the sea surface temperature gradients over the Indian Ocean. During the Long rains, the inter-annual rainfall variability over the Lake Victoria region was associated with the sea surface temperature anomaly over the Indian Ocean and for the East Africa region the associations were weak. The drivers during the Long Rains over East Africa region were then further investigated by splitting the season to the March–April and May periods. The March–April period was positively correlated to the West Pacific and Indian Ocean dipole index, while May was associated with the Quasi-Biennial Oscillation. In conclusion, although the model can reproduce the dominant modes of variability as in the observational data sets during the Short Rains, skill was lower during the Long Rains.

scholarly journals Incidence of Viruses Infecting Sweetpotato in Tanzania

Plant Disease ◽  
2004 ◽  
Vol 88 (9) ◽  
pp. 916-920 ◽  
Author(s):  
Fred Tairo ◽  
Alois Kullaya ◽  
Jari P. T. Valkonen
Keyword(s):  
Indian Ocean ◽  
Sweet Potato ◽  
Lake Victoria ◽  
Mottle Virus ◽  
Detection Methods ◽  
Enzyme Linked Immunosorbent Assay ◽  
Lake Victoria Basin ◽  
Prevalent Virus ◽  
Universal Indicator ◽  
The Indian Ocean

A survey for incidence of sweetpotato viruses was carried out in the three sweetpotato-producing districts (Bukoba, Misungwi, and Tarime) in the Lake Victoria basin and in the Indian Ocean coastal zone (Bagamoya on the mainland and Unguja on Zanzibar Island) in Tanzania in March and April 2003. A total of 170 plants from 43 sweetpotato fields were collected, established in an insect-proof screenhouse, and tested for viruses by nitrocellulose membrane enzyme-linked immunosorbent assay (NCM-ELISA). Scions from symptomless plants were grafted onto Ipomoea setosa, a nearly universal indicator plant for sweetpotato viruses, and leaves were tested by NCM-ELISA. Results were confirmed in several seropositive plants by cloning and partial sequencing of the viruses. Sweet potato feathery mottle virus (SPMFV), Sweet potato mild mottle virus, Sweet potato chlorotic stunt virus (SPCSV), and Sweet potato chlorotic fleck virus were detected serologically in single or mixed infections. Frequencies of occurrence of these viruses as determined by serological detection showed SPMFV to be the most prevalent virus in all the surveyed districts. Our study revealed a higher incidence and diversity of viruses in the Lake Victoria basin compared with the Indian Ocean coastal area. These results represent the first survey for sweetpotato viruses in Tanzania using accurate detection methods.

scholarly journals Differential Tropism in Roots and Shoots of Resistant and Susceptible Cassava (Manihot esculenta Crantz) Infected by Cassava Brown Streak Viruses

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1221
Author(s):  
Samar Sheat ◽  
Paolo Margaria ◽  
Stephan Winter
Keyword(s):  
Virus Replication ◽  
Central Africa ◽  
Streak Virus ◽  
Virus Infections ◽  
Long Distance ◽  
Manihot Esculenta Crantz ◽  
Cassava Brown Streak Virus ◽  
Cassava Brown Streak Disease ◽  
Long Distance Movement ◽  
Brown Streak

Cassava brown streak disease (CBSD) is a destructive disease of cassava in Eastern and Central Africa. Because there was no source of resistance in African varieties to provide complete protection against the viruses causing the disease, we searched in South American germplasm and identified cassava lines that did not become infected with the cassava brown streak viruses. These findings motivated further investigations into the mechanism of virus resistance. We used RNAscope® in situ hybridization to localize cassava brown streak virus in cassava germplasm lines that were highly resistant (DSC 167, immune) or that restricted virus infections to stems and roots only (DSC 260). We show that the resistance in those lines is not a restriction of long-distance movement but due to preventing virus unloading from the phloem into parenchyma cells for replication, thus restricting the virus to the phloem cells only. When DSC 167 and DSC 260 were compared for virus invasion, only a low CBSV signal was found in phloem tissue of DSC 167, indicating that there is no replication in this host, while the presence of intense hybridization signals in the phloem of DSC 260 provided evidence for virus replication in companion cells. In neither of the two lines studied was there evidence of virus replication outside the phloem tissues. Thus, we conclude that in resistant cassava lines, CBSV is confined to the phloem tissues only, in which virus replication can still take place or is arrested.

scholarly journals Cassava brown streak virus has a rapidly evolving genome: implications for virus speciation, variability, diagnosis and host resistance

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Titus Alicai ◽  
Joseph Ndunguru ◽  
Peter Sseruwagi ◽  
Fred Tairo ◽  
Geoffrey Okao-Okuja ◽  
...  
Keyword(s):  
Host Resistance ◽  
Streak Virus ◽  
Cassava Brown Streak Virus ◽  
Brown Streak

Shipping and Trade between Hamburg-Bremen and the Indian Ocean, 1870–1914

1982 ◽  
Vol 13 (2) ◽  
pp. 349-386
Author(s):  
Hermann Kellenbenz
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
First World War ◽  
The Philippines ◽  
Early Years ◽  
World War ◽  
Short Survey ◽  
The First World War ◽  
The Indian Ocean ◽  
First World

This study is intended to give a short survey on the development of shipping and trade between two main German ports and the Indian Ocean from the early years of the Bismarck period to the beginning of the First World War. The study deals with the area from East Africa to East India and from Indochina to Indonesia. China, the Philippines, and Australia will not be considered. It is based on an analysis of published material.

scholarly journals The Geology of Portuguese Nyasaland

1922 ◽  
Vol 59 (5) ◽  
pp. 200-212
Author(s):  
Robert R. Walls
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
The South ◽  
The North ◽  
Dark Continent ◽  
The Indian Ocean

Portuguese Nyasaland is the name given to the most northern part of Portuguese East Africa, lying between Lake Nyasa and the Indian Ocean. It is separated from the Tanganyika territory in the north by the River Rovuma and from the Portuguese province of Mozambique in the south by the River Lurio. The territory measures about 400 miles from east to west and 200 miles from north to south and has an area of nearly 90,000 square miles. This territory is now perhaps the least known part of the once Dark Continent, but while the writer was actually engaged in the exploration of this country in 1920–1, the Naval Intelligence Division of the British Admiralty published two handbooks, the Manual of Portuguese East Africa and the Handbook of Portuguese Nyasaland, which with their extensive bibliographies contained practically everything that was known of that country up to that date (1920). These handbooks make it unnecessary in this paper to give detailed accounts of the work of previous explorers.

Myanmar Coastal Area Field Survey after the December 2004 Indian Ocean Tsunami

2006 ◽  
Vol 22 (3_suppl) ◽  
pp. 285-294 ◽  
Author(s):  
Tint Lwin Swe ◽  
Kenji Satake ◽  
Than Tin Aung ◽  
Yuki Sawai ◽  
Yukinobu Okamura ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Real Time ◽  
West Coast ◽  
Coastal Area ◽  
Field Survey ◽  
Indian Ocean Tsunami ◽  
Sumatra Earthquake ◽  
The West ◽  
Tide Level ◽  
The Indian Ocean

A post-tsunami survey was conducted along the Myanmar coast two months after the 2004 Great Sumatra earthquake ( Mw=9.0) that occurred off the west coast of Sumatra and generated a devastating tsunami around the Indian Ocean. Visual observations, measurements, and a survey of local people's experiences with the tsunami indicated some reasons why less damage and fewer casualties occurred in Myanmar than in other countries around the Indian Ocean. The tide level at the measured sites was calibrated with reference to a real-time tsunami datum, and the tsunami tide level range was 2–3 m for 22 localities in Myanmar. The tsunami arrived three to four hours after the earthquake.

scholarly journals Prolific Lightning and Thunderstorm Initiation over the Lake Victoria Basin in East Africa

2020 ◽  
Vol 148 (5) ◽  
pp. 1971-1985 ◽  
Author(s):  
Katrina S. Virts ◽  
Steven J. Goodman
Keyword(s):  
East Africa ◽  
Hot Spots ◽  
Seasonal Cycle ◽  
Lake Victoria ◽  
Intertropical Convergence Zone ◽  
Lake Victoria Basin ◽  
The Earth ◽  
Total Lightning ◽  
Average Cluster

Abstract The Lake Victoria basin of East Africa is home to over 30 million people, over 200 000 of whom are employed in fishing or transportation on the lake. Approximately 3000–5000 individuals are killed by thunderstorms yearly, primarily by outflow winds and resulting large waves. Prolific lightning activity and thunderstorm initiation in the basin are examined using continuous total lightning observations from the Earth Networks Global Lightning Network (ENGLN) for September 2014–August 2018. Seasonal shifts in the intertropical convergence zone produce semiannual lightning maxima over the lake. Diurnally, solar heating and lake and valley breezes produce daytime lightning maxima north and east of the lake, while at night the peak lightning density propagates southwestward across the lake. Cluster analysis reveals terrain-related thunderstorm initiation hot spots northeast of the lake; clusters also initiate over the lake and northern lowlands. The most prolific clusters initiate between 1100 and 1400 LT, about 1–2 h earlier than the average cluster. Most daytime thunderstorms dissipate without reaching Lake Victoria, and annually 85% of clusters producing over 1000 flashes over Lake Victoria initiate in situ. Initiation times of prolific Lake Victoria clusters exhibit a bimodal seasonal cycle: equinox-season thunderstorms initiate most frequently between 2200 and 0400 LT, while solstice-season thunderstorms initiate most frequently from 0500 to 0800 LT, more than 12 h after the afternoon convective peak over land. More extreme clusters are more likely to have formed over land and propagated over the lake, including 36 of the 100 most extreme Lake Victoria thunderstorms. These mesoscale clusters are most common during February–April and October–November.

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