scholarly journals SWEETPOTATO VIRUS DISEASES RESEARCH IN EAST AFRICA

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 517B-517
Author(s):  
D.W. Miano ◽  
D. R. LaBonte ◽  
C. A. Clark
Keyword(s):  
East Africa ◽  
Sweet Potato ◽  
Virus Disease ◽  
Lake Victoria ◽  
Virus Detection ◽  
Sub Saharan Africa ◽  
Mottle Virus ◽  
Virus Infections ◽  
Detection Techniques ◽  
Sub Saharan

Sweetpotato is an important staple food crop in Sub-Saharan Africa, with production being concentrated in East Africa, particularly around Lake Victoria. Productivity of the crop is greatly constrained by viral diseases. Four main viruses have consistently been detected from various surveys done in the region viz. sweet potato feathery mottle virus (SPFMV), sweet potato chlorotic stunt virus (SPCSV), sweet potato mild mottle virus (SPMMV), and sweet potato chlorotic fleck virus (SPCFV). Sweet potato caulimo-like virus (SPCaLV), sweet potato latent virus (SPLV), and cucumber mosaic virus (CMV) have also been detected though only in isolated cases. The most severe symptoms have been caused by co-infection with SPCSV and SPFMV, resulting in the synergistic Sweet potato virus disease (SPVD). Yield reductions due to virus infections have been estimated to be >90% in very severe cases. Virus detection has mainly been limited to the use of serological methods. Some plants have been observed with symptoms resembling those caused by viruses, but do not react with available antisera, indicating that the plants could be infected with viruses that have not been described, or not tested in the region. Use of other detection techniques such as PCR may result in identification of more viruses in the region. This report gives a summary of our research efforts towards detection of other viruses present in the region, and identification of resistant germplasm.

scholarly journals Detection and Distribution of Viruses Infecting Field-grown Sweetpotato in East Africa

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 972A-972
Author(s):  
Douglas Miano ◽  
Don LaBonte ◽  
Christopher Clark
Keyword(s):  
East Africa ◽  
Virus Disease ◽  
Lake Victoria ◽  
Sub Saharan Africa ◽  
Mottle Virus ◽  
Small Holder Farmers ◽  
Sub Saharan ◽  
First Time ◽  
Small Holder ◽  
Infected Vine

Sweetpotato is an important staple food crop in Sub-Saharan Africa, with production being concentrated in East Africa, particularly around Lake Victoria. Productivity of the crop is greatly constrained by viral diseases. Four main viruses have consistently been detected from various surveys done in the region viz., sweetpotato feathery mottle virus (SPFMV), sweetpotato chlorotic stunt virus (SPCSV), sweetpotato mild mottle virus (Sp.m.MV), and sweetpotato chlorotic fleck virus (SPCFV). The most severe symptoms have been caused by co-infection with SPCSV and SPFMV, resulting in the synergistic sweetpotato virus disease (SPVD). Some local sweetpotato genotypes have been reported to recover from, or have localized distribution of SPVD, suggesting that the disease is not fully systemic. This has led to the suggestion that uninfected cuttings may be obtained from previously infected plants. Experiments were set to determine the possibility of obtaining cuttings long enough for propagation that are free from virus infection. This would form a basis for recommending to the local small-holder farmers of a way to reduce losses due to the disease. Field-grown sweetpotato vines were cut into three pieces (15, 15–30, and >30 cm from the apex) and tested for SPCSV and SPFMV. Nine genotypes were selected from a group of 21 local clones and used for this study. The two viruses were equally present in all the three sections of infected vines, indicating that it is not easy to obtain a virus-free cutting for field propagation from an infected vine. Virus assays in the past has mainly been limited to the use of serological methods. Use of PCR resulted in detection of begomoviruses infecting sweetpotatoes for the first time in the region.

scholarly journals Incidence of Viruses and Virus like Diseases of Sweetpotato in Uganda

Plant Disease ◽  
2003 ◽  
Vol 87 (4) ◽  
pp. 329-335 ◽  
Author(s):  
Settumba B. Mukasa ◽  
Patrick R. Rubaihayo ◽  
Jari P. T. Valkonen
Keyword(s):  
Sweet Potato ◽  
Virus Disease ◽  
Disease Incidence ◽  
Mottle Virus ◽  
Sequence Information ◽  
Virus Infections ◽  
Tall Grass ◽  
Persistent Symptoms ◽  
Agroecological Zones ◽  
Mukono District

Sweetpotato plants were surveyed for viruslike diseases and viruses in the four major agroecological zones of Uganda. Testing of 1,260 sweetpotato plants, of which 634 had virus-like symptoms, showed that virus disease incidence ranged from 2.7% (Soroti district, short grassland—savannah zone) to 20% (Mukono district, tall grass—forest mosaic zone). Sweet potato chlorotic stunt virus (SPCSV), Sweet potato feathery mottle virus (SPFMV), Sweet potato mild mottle virus (SPMMV), and sweet potato chlorotic fleck virus (SPCFV) were serologically detected and positive results confirmed by immunocapture reverse transcriptase polymerase chain reaction (IC-RT-PCR) and subsequent sequence analyses of the amplified fragments, except SPCFV, which lacked sequence information. SPCSV and SPFMV were detected in all the 14 districts surveyed, whereas SPMMV and SPCFV were detected in 13 and 8 districts, respectively. Logistic regression analysis revealed that SPCSV and SPFMV, SPFMV and SPMMV, and SPFMV and SPCFV more frequently occurred together than any other virus combinations or as single virus infections. Co-infections of SPCSV with SPFMV and/or SPMMV were associated with more severe and persistent symptoms than infections with each of the viruses alone. Several plants (11%) displaying viruslike symptoms did not react with the virus antisera used, suggesting that more viruses or viruslike agents are infecting sweetpotatoes in Uganda.

scholarly journals A first global phylogeny ofMaize chlorotic mottle virus

2017 ◽  
Author(s):  
Luke A Braidwood ◽  
Diego F Quito-Avila ◽  
Darlene Cabanas ◽  
Alberto Bressan ◽  
Anne Wangai ◽  
...  
Keyword(s):  
East Africa ◽  
Total Yield ◽  
Sub Saharan Africa ◽  
Mottle Virus ◽  
Adjusted Rand Index ◽  
Maize Production ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Sub Saharan

ABSTRACTMaize chlorotic mottle virushas been rapidly spreading around the globe over the past decade. The interactions ofMaize chlorotic mottle viruswith potyviridae viruses causes an aggressive synergistic viral condition - maize lethal necrosis, which can cause total yield loss. Maize production in sub-Saharan Africa, where it is the most important cereal, is threatened by the arrival of maize lethal necrosis. We obtainedMaize chlorotic mottle virusgenome sequences from across East Africa and for the first time from Ecuador and Hawaii, and constructed a phylogeny which highlights the similarity of Chinese to African isolates, and Ecuadorian to Hawaiian isolates. We used a measure of clustering, the adjusted Rand index, to extract region-specific SNPs and coding variation that can be used for diagnostics. The population genetics analysis we performed shows that the majority of sequence diversity is partitioned between populations, with diversity extremely low within China and East Africa.

scholarly journals Natural Wild Hosts of Sweet potato feathery mottle virus Show Spatial Differences in Virus Incidence and Virus-Like Diseases in Uganda

2008 ◽  
Vol 98 (6) ◽  
pp. 640-652 ◽  
Author(s):  
A. K. Tugume ◽  
S. B. Mukasa ◽  
J. P. T. Valkonen
Keyword(s):  
East Africa ◽  
Sweet Potato ◽  
Virus Disease ◽  
Mottle Virus ◽  
Wild Plants ◽  
East African ◽  
Virus Incidence ◽  
Close Proximity ◽  
Natural Hosts ◽  
Spatial Differences

Sweet potato feathery mottle virus (SPFMV, genus Potyvirus) is globally the most common pathogen of sweetpotato. An East African strain of SPFMV incites the severe ‘sweetpotato virus disease’ in plants co-infected with Sweet potato chlorotic stunt virus and threatens subsistence sweetpotato production in East Africa; however, little is known about its natural hosts and ecology. In all, 2,864 wild plants growing in sweetpotato fields or in their close proximity in Uganda were observed for virus-like symptoms and tested for SPFMV in two surveys (2004 and 2007). SPFMV was detected at different incidence in 22 Ipomoea spp., Hewittia sublobata, and Lepistemon owariensis, of which 19 species are new hosts for SPFMV. Among the SPFMV-positive plants, ≈60% displayed virus-like symptoms. Although SPFMV incidence was similar in annual and perennial species, virus-like diseases were more common in annuals than perennials. Virus-like diseases and SPFMV were more common in the eastern agroecological zone than the western, central, and northern zones, which contrasted with known incidence of SPFMV in sweetpotato crops. The data on a large number of new natural hosts of SPFMV detected in this study provide novel insights into the ecology of SPFMV in East Africa.

scholarly journals Incidence and distribution of Sweetpotato viruses and their implication on sweetpotato seed system in Malawi

2021 ◽  
Author(s):  
Willard Mbewe ◽  
Andrew Mtonga ◽  
Margret Chiipanthenga ◽  
Kennedy Masamba ◽  
Gloria Chitedze ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Virus Disease ◽  
Disease Incidence ◽  
Mottle Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Foliar Symptoms ◽  
Membrane Enzyme ◽  
Sweet Potato Virus ◽  
Seed System ◽  
Clean Seed

AbstractA survey was carried out in 19 districts to investigate the prevalence and distribution of sweetpotato virus disease (SPVD) and its implication on the sustainability of clean seed system in Malawi. A total of 166 leaf samples were collected and tested for the presence of 8 viruses using nitrocellulose membrane enzyme-linked immunosorbent assay (NCM-ELISA). SPVD foliar symptoms were observed in 68.42% of the surveyed districts. There were significant variations in disease incidence and severity (p < 0.001) among districts, with the highest incidence in Mulanje (28.34%). Average SPVD severity score was 3.05. NCM-ELISA detected sweet potato feathery mottle virus (SPFMV, 30.54%), sweet potato mild mottle virus (SPMMV, 31.14%), sweet potato mild speckling virus (SPMSV, 16.17%), sweet potato C-6 virus (SPC6V, 13.77%), sweet potato chlorotic stunt virus (SPCSV, 22.16%), sweet potato collusive virus (SPCV, 30.54%), sweet potato virus G (SPVG, 11.38%), cucumber mosaic virus (CMV, 7.78%) either in single or mixed infections. Data from this study indicate a significant SPVD occurrence in the country, and the consequence implications towards national sweetpotato seed system.

scholarly journals Plasmodium vivax from Duffy-Negative and Duffy-Positive Individuals Shares Similar Gene Pool in East Africa

2021 ◽  
Author(s):  
Daniel Kepple ◽  
Alfred Hubbard ◽  
Musab M Ali ◽  
Beka R Abargero ◽  
Karen Lopez ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
East Africa ◽  
Sub Saharan Africa ◽  
Road Density ◽  
Genetic Characteristics ◽  
Plasmodium Vivax Malaria ◽  
Genetic Clusters ◽  
Sub Saharan ◽  
The Impact ◽  
Duffy Negative

Abstract Plasmodium vivax malaria was thought to be rare in Africa, but an increasing number of P. vivax cases reported across Africa and in Duffy-negative individuals challenges this conventional dogma. The genetic characteristics of P. vivax in Duffy-negative infections, the transmission of P. vivax in East Africa, and the impact of environments on transmission remain largely unknown. This study examined genetic and transmission features of P. vivax from 107 Duffy-negative and 305 Duffy-positive individuals in Ethiopia and Sudan. No clear genetic differentiation was found in P. vivax between the two Duffy groups, indicating between-host transmission. P. vivax from Ethiopia and Sudan showed similar genetic clusters, except samples from Khartoum, possibly due to distance and road density that inhibited parasite gene flow. This study is the first to show that P. vivax can transmit to and from Duffy-negative individuals and provides critical insights into the spread of P. vivax in sub-Saharan Africa.

scholarly journals Study of the genetic heterogeneity of SAT-2 foot-and-mouth disease virus in sub-Saharan Africa with specific focus on East Africa

2007 ◽  
Vol 74 (4) ◽  
Author(s):  
M. Sahle ◽  
R.M. Dwarka ◽  
E.H. Venter ◽  
W. Vosloo
Keyword(s):  
East Africa ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Sub Saharan Africa ◽  
Gene Encoding ◽  
Western Africa ◽  
Mouth Disease Virus ◽  
Foot And Mouth ◽  
Sub Saharan ◽  
Unrelated Strain

The epidemiology of serotype SAT-2 foot-and-mouth disease was investigated in sub-Saharan Africa by phylogenetic analysis using the 1D gene encoding the major antigenic determinant. Fourteen genotypes were identified of which three are novel and belong to East Africa, bringing the total number of genotypes for that region to eight. The genotypes clustered into three lineages that demonstrated surprising links between East, southern and south-western Africa. One lineage was unique to West Africa. These results established numerous incursions across country borders in East Africa and long term conservation of sequences for periods up to 41 years. Ethiopia, Kenya and Uganda have all experienced outbreaks from more than one unrelated strain, demonstrating the potential for new introductions. The amount of variation observed within this serotype nearly equalled that which was found between serotypes; this has severe implications for disease control using vaccination.

M-Kopa Solar: Lighting up the Dark Continent

2018 ◽  
Vol 7 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Charu Rastogi
Keyword(s):  
East Africa ◽  
Low Income ◽  
Sub Saharan Africa ◽  
Mobile Payments ◽  
Energy Delivery ◽  
The Poor ◽  
Dark Continent ◽  
Solar Lighting ◽  
Sub Saharan ◽  
Grave Problem

M-Kopa Solar is a pay-as-you-go provider of solar home systems, catering to low-income, off-grid customers in East Africa. The company goes by the tagline, ‘Power for Everyone’. Using mobile payments system and an innovative approach to energy delivery, M-Kopa succeeded in building a business which solved a grave problem for the poorest of the poor and has the potential to become a billion dollar enterprise. The case begins with a description of the background in which M-Kopa is operating. It goes on to explain how M-Kopa used the infrastructure gap in sub-Saharan Africa as an opportunity and propagated solar power as an alternative to traditional energy. Finally, it lays out the challenges M-Kopa may face on its expansion spree.

Sign in / Sign up

Export Citation Format

Share Document