Evaluation and Deployment of Rice Genotypes Resistant to Rice Yellow Mottle Virus Disease in the Southern Highlands of Tanzania

Rice yellow mottle virus (RYMV) is the most important biotic stress undermining productivity of the crop envisaged to spur economic growth and improvement of livelihoods in Tanzania. In efforts to exploit economic and ecofriendly natural host resistance for sustained disease management, reactions of 60 promising rice genotypes selected from various germplasm to a mixture of isolates of the virus under artificial inoculation in the Southern highlands zone represented by Kyela district were studied. Twenty of the most promising entries were further verified on farm at two lowland rainfed and two upland ecologies in the district. Resistance or susceptibility of the genotypes was determined by severity of symptoms as scored on a standard international evaluation scale ranging from 1 to 9 and plant height reduction measured as the difference in height between inoculated and uninoculated plants. Results indicated that RYMV isolates used differed by their virulence and the varieties by their vertical resistance. Observed reactions ranged from highly susceptible to highly resistant. About 50% of the genotypes showed a high level of resistance while 20% were highly susceptible. The intermediate reactions were 0% resistant, 10% susceptible and 20% moderately resistant. Susceptible cultivars recorded up to 75% reduction in height and death of plants whereas those resistant had mild symptoms and negligible plant height reduction. Highly resistant genotypes were immune to infection by the virus across all locations. Five of the highly resistant cultivars namely Salama M55, M57, M19, M35, IITA 235 were acceptable to farmers in terms of cycle length, plant and grain types. Further research to enable official release for commercial use and wide scale accessibility of seed to farmers was deemed necessary to ease damage from RYMV. The varieties can also be deployed as sources of resistance in cross breeding programmes to improve the local susceptible cultivars whose background is already acceptable to farmers. Exhaustive screening of germplasm collections to identify diverse sources of novel genes for resistance was also recommended together with verification of high resistance of genotypes across regions

Unprecedented alkylation of carboxylic acids by boron trifluoride etherate

The alkylation of carboxylic acids by an ethyl moiety of boron trifluoride etherate in the absence of ethyl alcohol from the reaction system is unexpected and novel. Both aromatic and aliphatic carboxylic acids were clearly alkylated affording good yields in short reaction times with the exception of nicotinic acid that necessitated an overnight reaction. It was noted that while ortho-substituted hydroxyl groups of carboxylic acids investigated were not affected by alkylation, those of meta- and para-substituted carboxylic acids were partially etherified. Furthermore, the alkylation reaction was found to be compatible with a range of functional groups such as halogens, amino and nitro groups except for the alkene function of undecylenic acid that underwent polymerisation with concomitant alkylation of its carboxylic acid function.               KEY WORDS: Carboxylic acids, Alkylation, Etherification, Functional groups, Boron trifluoride etherate Bull. Chem. Soc. Ethiop. 2018, 32(2), 387-392.DOI: https://dx.doi.org/10.4314/bcse.v32i2.1

Field Evaluation of the Photo-induced Electron Transfer Fluorogenic Primers (PET) Real-time PCR for the Detection of Plasmodium falciparum in Tanzania.

Accurate diagnosis of malaria infections remains challenging, especially in the identification of submicroscopic infections. New molecular diagnostic tools that are inexpensive, sensitive enough to detect low-level infections and suitable in laboratory settings of resource-limited countries are required for malaria control and elimination programmes. Here the diagnostic potential of a recently developed photo-induced electron transfer fluorogenic primer (PET) real-time polymerase chain reaction (PCR) called PET-PCR was investigated. This study aimed to (i) evaluate the use of this assay as a method for the detection of both Plasmodium falciparum and other Plasmodium species infections in a developing country's diagnostic laboratory; and, (ii) determine the assay's sensitivity and specificity compared to a nested 18S rRNA PCR. Samples used in this study were obtained from a previous study conducted in the region of Iringa, Tanzania. A total of 303 samples from eight health facilities in Tanzania were utilized for this evaluation. All samples were screened using the multiplex PET-PCR assay designed to detect Plasmodium genus and P. falciparum initially in laboratory in Tanzania and then repeated at a reference laboratory at the CDC in the USA. Microscopy data was available for all the 303 samples. A subset of the samples were tested in a blinded fashion to find the sensitivity and specificity of the PET-PCR compared to the nested 18S rRNA PCR. Compared to microscopy, the PET-PCR assay was 59% more sensitive in detecting P. falciparum infections. The observed sensitivity and specificity were 100% (95% confidence interval (CI0.95) = 94-100%) and (CI0.95 = 96-100%), respectively, for the PET-PCR assay when compared to nested 18S rRNA PCR. When compared to 18S rRNA PCR, microscopy had a low sensitivity of 40% (CI0.95 = 23-61%) and specificity of 100% (CI0.95 = 96-100%). The PET-PCR results performed in the field laboratory in Tanzania were in 100% concordance with the results obtained at the reference laboratory in the USA. The PET-PCR is a new molecular diagnostic tool with similar performance characteristics as commonly used PCR methods that is less expensive, easy to use, and amiable to large scale-surveillance studies in developing country settings

Survey of Potato aphid (Myzus persicae) from Selected on-farm Potato growing Areas in Mbeya and Njombe regions of Tanzania

Potato aphid green peach (Myzus persicae Sulzer) is one of the serious pests in potato (Solanum tuberosum) production areas in the world. A survey was carried out during 2014 potato growing season to assess aphid and Coccinellid population abundance in potato production areas in Mbeya and Njombe regions situated in southern highlands of Tanzania. Aphid and Coccinellid abundance were sampled from 30 leaves selected randomly from ten plants. Estimates of aphid abundance from potato fields were carried out from transectline replicated three times. A total of 1,370 aphid populations were sampled during the survey period. Abundance from young leaves was 898, followed by medium leaves 270 and the least was old leaves represented by 202 individuals. The relative abundance of aphid population resulted from 15 minutes sampling effort per transect ranked from 8 individuals from Swaya village to 171 individuals from Atwelo village and the rest were in between. The differences between selected plant parts showed significant differences (p = 0.001). The results from this survey provides database on aphid population and Coccinellid natural enemies of potato aphid in potato growing areas which can be used for future research in the selected regions. Key words: Myzus persicae, potato aphid, Coccinelli

Reservoir dynamics of rabies in Southeast Tanzania and the roles of cross-species transmission and domestic dog vaccination

1) Understanding the role of different species in the transmission of multi-host pathogens, such as rabies virus, is vital for effective control strategies. Across most of sub-Saharan Africa domestic dogs (Canis familiaris) are considered the reservoir for rabies, but the role of wildlife has been long debated. Here we explore the multi-host transmission dynamics of rabies across southeast Tanzania. 2) Between January 2011 and July 2019 data on probable rabies cases were collected in the regions of Lindi and Mtwara. Hospital records of animal-bite patients presenting to healthcare facilities were used as sentinels for animal contact tracing. The timing, location and species of probable rabid animals was used to reconstruct transmission trees to infer who infected whom and the relative frequencies of within-and between-species transmission. 3) During the study, 688 probable human rabies exposures were identified, resulting in 47 deaths. Of these exposures, 389 were from domestic dogs (56.5%) and 262 from jackals (38.1%). Over the same period 549 probable animal rabies cases were traced: 303 in domestic dogs (55.2%) and 221 in jackals (40.3%). 4) Although dog-to-dog transmission was most commonly inferred (40.5% of transmission events), a third of inferred events involved wildlife-to-wildlife transmission (32.6%) and evidence suggested some sustained transmission chains within jackal populations. 5) A steady decline in probable rabies cases in both humans and animals coincided with the implementation of widespread domestic dog vaccination during the first six years of the study. Following the lapse of this programme dog rabies cases began to increase in one of the northernmost districts. 6) Synthesis and applications: in southeast Tanzania, despite a relatively high incidence of rabies in wildlife and evidence of wildlife-to-wildlife transmission, domestic dogs remain essential to the reservoir of infection. Continued dog vaccination alongside improved surveillance would allow a fuller understanding of the role of wildlife in maintaining transmission in this area. Nonetheless, dog vaccination clearly suppressed rabies in both domestic dog and wildlife populations, reducing both public health and conservation risks and, if sustained, has potential to eliminate rabies from this region

Low specificity of determine HIV1/2 RDT using whole blood in south west Tanzania

Objective: To evaluate the diagnostic performance of two rapid detection tests (RDTs) for HIV 1/2 in plasma and in whole blood samples. Methods: More than 15,000 study subjects above the age of two years participated in two rounds of a cohort study to determine the prevalence of HIV. HIV testing was performed using the Determine HIV 1/2 test (Abbott) in the first (2006/2007) and the HIV 1/2 STAT-PAK Dipstick Assay (Chembio) in the second round (2007/2008) of the survey. Positive results were classified into faint and strong bands depending on the visual appearance of the test strip and confirmed by ELISA and Western blot. Results: The sensitivity and specificity of the Determine RDT were 100% (95% confidence interval = 86.8 to 100%) and 96.8% (95.9 to 97.6%) in whole blood and 100% (99.7 to 100%) and 97.9% (97.6 to 98.1%) in plasma respectively. Specificity was highly dependent on the tested sample type: when using whole blood, 67.1% of positive results were false positive, as opposed to 17.4% in plasma. Test strips with only faint positive bands were more often false positive than strips showing strong bands and were more common in whole blood than in plasma. Evaluation of the STAT-PAK RDT in plasma during the second year resulted in a sensitivity of 99.7% (99.1 to 99.9%) and a specificity of 99.3% (99.1 to 99.4%) with 6.9% of the positive results being false. Conclusions: Our study shows that the Determine HIV 1/2 strip test with its high sensitivity is an excellent tool to screen for HIV infection, but that – at least in our setting – it can not be recommended as a confirmatory test in VCT campaigns where whole blood is used

"Ruvettiin jakamaan maapalloa keskenämme" : Helsingin Sanomien kehitysmaauutisointi vuosina 1965–1974

Tarkastelen tutkielmassani Helsingin Sanomien (HS) kehitysmaauutisointia vuosina 1965–1974. Tavoitteena on selvittää, miten yhteiskunnan ja journalismin merkittävä murroskohta heijastui Suomen suurimman sanomalehden välittämään maailmankuvaan. Päälähteinä ovat tekemäni aikalaistoimittajien haastattelut, Päivälehden arkiston teettämät toimittajahaastattelut ja muu arkistomateriaali sekä digitaalisessa muodossa löytyvät HS:n lehdet vuosilta 1965–1974. Tarkempi analyysi kohdistuu huhti- ja lokakuun lehtiin vuosina 1965, 1968, 1971 ja 1974. Tutkimukseni perusteella HS:n kehitysmaauutisoinnissa tapahtui selkeitä muutoksia. Vuonna 1965 pääpaino oli kansainvälisten uutistoimistojen sähkeuutisissa. Sähkeet kattoivat määrällisesti suuren joukon maita, mutta aiheiden käsittely jäi pintapuoliseksi ja näkökulmat olivat uutistoimistojen valitsemia. Omien toimittajien nimiin kirjattuja juttuja kehitysmaa-aiheista ei vuonna 1965 juuri ollut. Vuonna 1968 tilanne oli samankaltainen. Esimerkiksi maailmalla ja Suomessa suurta huomiota herättänyttä Biafran kriisiä ei analysoitu omien toimittajien voimin, eikä HS lähettänyt alueelle omaa toimittajaa. Vuoteen 1971 mennessä ulkomaantoimituksen omien toimittajien kirjoittamien, kehitysmaita käsittelevien juttujen määrä kasvoi selvästi. Myös pidempien artikkeleiden määrä lisääntyi, samoin tekstien kommentoiva ja kantaaottava tyyli. Vuonna HS:ssa oli jo kolme Euroopan ja Pohjois-Amerikan ulkopuolisia alueita seuraavaa toimittajaa. Vuosina 1971–1974 isoin muutos näyttäisi tapahtuneen aihepiirien laventumisessa: maailman eriarvoisuuteen ja humanitaarisiin ongelmiin liittyvät artikkelit lisääntyivät. Kehitysmaauutisoinnin rinnalle alkoi nousta kehitysmaajournalismi, joka pyrki tuomaan esiin kehityskysymyksiä ja kehitysmaiden näkökulmia. Myös kehitysmaita seuraavien toimittajien työmatkat kohdealueilleen lisääntyivät. Kaikki tutkimukseen haastatellut HS:n ulkomaantoimittajat olivat sitä mieltä, että uutispäällikkö Olli Kivisellä oli merkittävä rooli uudenlaisen uutisoinnin muovaajana. Taustalla vaikutti myös Aatos Erkon vuonna 1965 käynnistämä muutosprosessi HS:n uudistamiseksi. Erkko halusi huomioida ajan hengen ja avasi ovet nuorelle, usein vasemmistolaiselle, toimittajapolvelle. Tutkimukseni tarkastelujaksolla HS:n kehitysmaita seuraavat toimittajat olivat 1940-luvulla syntyneitä nuoria miehiä, joilla yliopisto-opinnot olivat juuri takana tai meneillään. Kaikki olivat aatemaailmaltaan selkeästi vasemmistolaisia, ja kirjoitusten pontimena oli halu valistaa lukijoita ja vaikuttaa siihen, että imperialistinen maailmanjärjestys jää historiaan. Vaikka HS säilyi arvoiltaan oikeistoliberaalina, se näyttää sallineen “radikaalitoimittajilleen” hyvinkin vasemmistolaisia kannanottoja varsinkin vuosina 1969–1974

Towards a coordinated strategy for intercepting human disease emergence in Africa

Non peer reviewe