scholarly journals An update of sweet potato viral disease incidence and spread in Ethiopia

2020 ◽  
Vol 16 (8) ◽  
pp. 1116-1126 ◽  
Author(s):  
H. Buko D. ◽  
Gedebo A. ◽  
Spetz C. ◽  
K. Hvoslef-Eide A.
Keyword(s):  
Sweet Potato ◽  
Disease Incidence ◽  
Viral Disease

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 Interaction between potyvirus and crinivirus in sweet potato

2020 ◽  
Vol 50 ◽  
Author(s):  
Sofía Solange Flamarique ◽  
Antonella Vilanova Perez ◽  
Andrea Peña Malavera ◽  
Julia Martino ◽  
Liliana Di Feo
Keyword(s):  
Sweet Potato ◽  
Viral Disease ◽  
Multiple Infections ◽  
Plant Tissues ◽  
Post Inoculation ◽  
Indicator Plant ◽  
Susceptible Plant ◽  
Elisa Method ◽  
Sweet Potato Virus ◽  
Das Elisa

ABSTRACT Sweet potato, in Argentina, is affected by the “encrespamiento amarillo”, a viral disease in which seven viruses are involved, among them two potyvirus (sweet potato feathery mottle virus - SPFMV and sweet potato virus G - SPVG) and a crinivirus (sweet potato chlorotic stunt virus - SPCSV). This research aimed to study the interaction between SPFMV and SPVG with SPCSV in sweet potato. Two sweet potato cultivars (Gem and Arapey INIA) and Ipomoea setosa as an indicator susceptible plant were tested as single (SPFMV or SPVG), double (SPFMV + SPVG, SPFMV + SPCSV or SPVG + SPCSV) or triple (SPFMV + SPVG + SPCSV) grafts. Both potyviruses were purified and the viral concentrations in the plant tissues were quantified by the DAS-Elisa method. The viruses and their severities were evaluated at 7, 15, 21, 30 and 35 days post-inoculation. A synergistic effect was observed with the three viruses in the indicator plant. The viral concentration increase was 50 times for SPFMV (day 35) and two times for SPVG (day 21) in the Gem cultivar, and 1.89 times for SPFMV (day 35) and three times for SPVG (day 7) in the Arapey INIA. For multiple infections, the indicator plant and the Gem cultivar exhibited synergistic symptoms and increase in the viral titers, with a higher severity and variability of the symptoms. Co-infections such as SPFMV + SPVG showed characteristic potyvirus symptoms, without increasing the viral concentrations; triple co-infections exhibited viral complex symptoms, with increase in the potyvirus titers; and the symptoms were mild or imperceptible in the simple infections.

Recovery from Mosaic Caused by Sorghum Mosaic Virus in Sugarcane and Impact on Yield

Plant Disease ◽  
2020 ◽  
Vol 104 (12) ◽  
pp. 3166-3172
Author(s):  
J. L. Rice ◽  
J. W. Hoy
Keyword(s):  
Virus Infection ◽  
Mosaic Virus ◽  
Disease Incidence ◽  
Viral Disease ◽  
Pcr Assay ◽  
Susceptibility To Infection ◽  
Reverse Transcription Pcr ◽  
Rate Of Increase ◽  
Crop Cycle ◽  
The Impact

Mosaic is a historically important viral disease of sugarcane in Louisiana caused by Sugarcane mosaic virus and, currently, by Sorghum mosaic virus (SrMV). Sugarcane clones can have variable responses to mosaic for different traits, including susceptibility to infection and yield loss. Disease incidence and rate of increase within a multiple-year crop cycle is affected by susceptibility and other epidemiological factors, possibly including recovery from symptom expression and virus infection. Recovery (defined as the emergence of asymptomatic plants from buds on planted symptomatic stalks) and the impact of mosaic on yield components were evaluated in two sugarcane cultivars, HoCP 09-804 and L 10-147. Recovery varied between the two cultivars. Across two experiments, L 10-147 had a higher frequency of recovery (range 9.4 to 19.8%) than HoCP 09-804 (range 0.9 to 2.3%). A reverse-transcription PCR assay did not detect SrMV in 96.5% of 143 L 10-147 leaf samples and 83.3% of 6 HoCP 09-804 leaf samples collected from recovered plants. When comparing symptomatic and asymptomatic plantings, mosaic reduced cane and sucrose yield in HoCP 09-804 but not L 10-147, suggesting a possible association between recovery and tolerance to virus infection.

scholarly journals First Report of Ranunculus mild mosaic virus on Ranunculus asiaticus in Yunnan Province, China

Plant Disease ◽  
2008 ◽  
Vol 92 (11) ◽  
pp. 1585-1585 ◽  
Author(s):  
J. H. Wang ◽  
S. Zhao ◽  
X. M. Yang
Keyword(s):  
Mosaic Virus ◽  
Yunnan Province ◽  
Disease Incidence ◽  
Viral Disease ◽  
Mild Mosaic ◽  
Rt Pcr ◽  
Potential Threat ◽  
First Report ◽  
Ranunculus Asiaticus ◽  
Mild Mosaic Virus

In June 2007, a new viral disease occurred in commercial fields of Ranunculus asiaticus in the Yunnan Province of China. Infected plants exhibited mosaic symptoms and growth abnormalities. Viral disease incidence for this ornamental crop host in the Yunnan Province was estimated to range from 10 to 20%. Electron microscopic examination of negatively stained leaf-dip preparations from symptomatic plants identified long, flexuous linear particles (approximately 800 nm). The samples were tested using indirect antigen-coated plate (ACP)-ELISA. ACP-ELISA results showed that the leaf samples from symptomatic plants reacted positively to the potyvirus group antibody (Agdia Inc., Eklhart, IN). Total nucleic acid extracted from symptomatic plants was tested using reverse transcription (RT)-PCR with primers (S 5′-GGNAAAAYAGYGGNCARCC-3′; M4: 5′-GTTTTCCCAGTCACGAC-3′ [N = A, G, C, or T; Y = C or T; and R = A or G]) designed to amplify the 3′ terminal region of genomic RNA of the genus Potyvirus (1). RT-PCR produced a 1,650-bp amplification product that was cloned and sequenced (GenBank Accession No. EU684747). The sequenced portion showed 90 and 99% identity with the Ranunculus mild mosaic virus (RMMV) isolates (GenBank Accession Nos. DQ152191 and EF445546) from Italy and Israel, respectively (2). To our knowledge, this is the first report of RMMV in China. Infection from this virus may cause losses for cut-flower production of Ranunculus asiaticu and it is also a potential threat for international trade of Ranunculus germplasm. References: (1) J. Chen and J. P. Chen. Chin. J. Virol. 18:371, 2002. (2) M. Turina et al. Phytopathology 96:560, 2006.

Comparison of Pest Occurrence and Viral Disease Incidence Rate with Reduced the Application of Pesticides in Red Pepper Field

2021 ◽  
Vol 25 (1) ◽  
pp. 1-10
Author(s):  
Tae-young Kim ◽  
Cheol Jang ◽  
Hyun-woo Kang ◽  
Jae-hyuk Choi ◽  
Ho-wook Lee ◽  
...  
Keyword(s):  
Incidence Rate ◽  
Disease Incidence ◽  
Viral Disease ◽  
Red Pepper

Effectiveness of Contact Tracing on Viral Disease Mitigation and Suppression: An Evidence-Based Review (Preprint)

2021 ◽  
Author(s):  
Kelly Jean Craig ◽  
Rubina Rizvi ◽  
Van C Willis ◽  
William J Kassler ◽  
Gretchen Purcell Jackson
Keyword(s):  
Public Health ◽  
Social Interactions ◽  
Scientific Literature ◽  
Disease Incidence ◽  
Viral Disease ◽  
Contact Tracing ◽  
Evidence Based ◽  
Inclusion Criteria ◽  
Disease Outcomes ◽  
Effective Public Health

BACKGROUND Contact tracing in association with quarantine and isolation is an important public health tool to control outbreaks of infectious diseases. This strategy has been widely implemented in the current coronavirus disease 2019 (COVID-19) pandemic. The effectiveness of this non-pharmaceutical intervention (NPI) is largely dependent on social interactions within the population and its combination with other interventions. Given the high transmissibility of SARS-CoV-2, small serial intervals, and asymptomatic transmission patterns, the effectiveness of contact tracing for this novel agent is largely unknown. OBJECTIVE To identify and synthesize evidence regarding the effectiveness of contact tracing on infectious viral disease outcomes based on prior scientific literature. METHODS An evidence-based review was conducted to identify studies from MEDLINE (including pre-print medRxiv server content) related to the effectiveness of contact tracing in viral outbreaks. The search dates were from database inception to July 24, 2020. Outcomes of interest were measures of incidence, transmission, hospitalization, and mortality. RESULTS Out of 159 unique records retrieved, 45 records were reviewed at the full-text level, with 24 meeting all inclusion criteria. Included studies utilized mathematical modeling (n=14), observational (n=8), and systematic review (n=2) approaches. Only two studies considered digital contact tracing. Contact tracing was mostly evaluated in combination with other NPIs and/or pharmaceutical interventions (PIs). While some degree of effectiveness in decreasing viral disease incidence, transmission, and resulting hospitalizations and mortality was observed, these results were highly dependent on epidemic severity (R0 value), number of contacts traced (including pre-symptomatic and asymptomatic cases), timeliness, duration, and compliance with combination interventions such as isolation, quarantine, and treatment. Contact tracing effectiveness was particularly limited by logistical challenges associated with increased outbreak size and speed of spread. CONCLUSIONS Timely deployment of contact tracing strategically layered with other NPIs could be an effective public health tool for mitigating and suppressing infectious outbreaks by decreasing viral disease incidence, transmission, and resulting hospitalizations and mortality.

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.

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