Evaluation of the diagnostic performance of PanbioTM Abbott SARS-CoV-2 rapid antigen test for the detection of COVID-19 from suspects attending ALERT center

BACKGROUND: The emergence and rapid spread of coronavirus disease 2019 (COVID-19), a potentially lethal disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is causing public health issues around the world. In resource-constrained nations, rapid Abbott SARS-CoV-2 antigen test kits are critical for addressing diagnostic gaps in health institutions and community screening. However, there is no evidence or proof of diagnostic performance in Ethiopia. The aim of this study was to compare the performance of PanbioTM Abbott SARS-CoV-2antigen rapid test kit to the gold standard, RT-PCR, in COVID-19 patients with clinical symptoms suggestive of COVID-19. METHOD: A prospective, cross-sectional study was conducted between November 2021 and April 2022, on 120 suspected patients recruited from outpatient, emergency, and intensive care units in one of the tertiary hospitals in Ethiopia. Nasopharyngeal swabs were collected from suspected cases and were tested using the Abbott SARS-CoV-2 kit, a rapid diagnostic test (RDT) and compared to the reference standard RT-PCR. RESULT: The sensitivity and specificity of the RDT were 74.2% and 100%, respectively. A total of 62 samples (51.6%) were RT-PCR positive. Of these, 46 were Ag-RDT positive. Sensitivity among symptomatic patients was 79.4% (95% CI 68.3-90). The Abbot RDT and RT-PCR had a Kappa value of agreement of 0.735 (p < 0.001). These values were acceptable when compared to the WHO's suggested thresholds. CONCLUSION: The finding from this study support the use of the Abbot RDT as a diagnostic tool in COVID-19 suspects, mainly in those with higher viral loads

T-cell regulation in Erythema Nodosum Leprosum.

Leprosy is a disease caused by Mycobacterium leprae where the clinical spectrum correlates with the patient immune response. Erythema Nodosum Leprosum (ENL) is an immune-mediated inflammatory complication, which causes significant morbidity in affected leprosy patients. The underlying cause of ENL is not conclusively known. However, immune-complexes and cell-mediated immunity have been suggested in the pathogenesis of ENL. The aim of this study was to investigate the regulatory T-cells in patients with ENL. Forty-six untreated patients with ENL and 31 non-reactional lepromatous leprosy (LL) patient controls visiting ALERT Hospital, Ethiopia were enrolled to the study. Blood samples were obtained before, during and after prednisolone treatment of ENL cases. Peripheral blood mononuclear cells (PBMCs) were isolated and used for immunophenotyping of regulatory T-cells by flow cytometry. Five markers: CD3, CD4 or CD8, CD25, CD27 and FoxP3 were used to define CD4+ and CD8+ regulatory T-cells. Clinical and histopathological data were obtained as supplementary information. All patients had been followed for 28 weeks. Patients with ENL reactions had a lower percentage of CD4+ regulatory T-cells (1.7%) than LL patient controls (3.8%) at diagnosis of ENL before treatment. After treatment, the percentage of CD4+regulatory T-cells was not significantly different between the two groups. The percentage of CD8+ regulatory T-cells was not significantly different in ENL and LL controls before and after treatment. Furthermore, patients with ENL had higher percentage of CD4+ T-ells and CD4+/CD8+ T-cells ratio than LL patient controls before treatment. The expression of CD25 on CD4+ and CD8+ T-cells was not significantly different in ENL and LL controls suggesting that CD25 expression is not associated with ENL reactions while FoxP3 expression on CD4+ T-cells was significantly lower in patients with ENL than in LL controls. We also found that prednisolone treatment of patients with ENL reactions suppresses CD4+ T-cell but not CD8+ T-cell frequencies. Hence, ENL is associated with lower levels of T regulatory cells and higher CD4+/CD8+ T-cell ratio. We suggest that this loss of regulation is one of the causes of ENL

Bovine tuberculosis at a cattle-small ruminant-human interface in Meskan, Gurage region, Central Ethiopia

ABSTRACT: BACKGROUND: Bovine tuberculosis (BTB) is endemic in Ethiopian cattle. The aim of this study was to assess BTB prevalence at an intensive contact interface in Meskan Woreda (district) in cattle, small ruminants and suspected TB-lymphadenitis (TBLN) human patients. METHODS: The comparative intradermal test (CIDT) was carried out for all animals involved in the cross-sectional study and results interpreted using a < 4 mm and a < 2 mm cut-off. One PPD positive goat was slaughtered and lymph nodes subjected to culture and molecular typing. In the same villages, people with lymphadenitis were subjected to clinical examination. Fine needle aspirates (FNA) were taken from suspected TBLN and analyzed by smear microscopy and molecular typing. RESULTS: A total of 1214 cattle and 406 small ruminants were tested for BTB. In cattle, overall individual prevalence (< 2 mm cut-off) was 6.8% (CI: 5.4-8.5%) with 100% herd prevalence. Only three small ruminants (2 sheep and 1 goat) were reactors. The overall individual prevalence in small ruminants (< 2 mm cut-off) was 0.4% (CI: 0.03-5.1%) with 25% herd prevalence. Cattle from owners with PPD positive small ruminants were all PPD negative. 83% of the owners kept their sheep and goats inside their house at night and 5% drank regularly goat milk.FNAs were taken from 33 TBLN suspected cases out of a total of 127 screened individuals with lymph node swellings. Based on cytology results, 12 were confirmed TBLN cases. Nine out of 33 cultures were AFB positive. Culture positive samples were subjected to molecular typing and they all yielded M. tuberculosis. M. tuberculosis was also isolated from the goat that was slaughtered. CONCLUSIONS: This study highlighted a low BTB prevalence in sheep and goats despite intensive contact with cattle reactors. TBLN in humans was caused entirely by M. tuberculosis, the human pathogen. M. tuberculosis seems to circulate also in livestock but their role at the interface is unknow

Mechanical transmission and survival of bacterial wilt on enset

The transmission of enset bacterial wilt with contaminated knives and the survival of the causal agent in soil and enset plant debris was studied at the Awassa Agricultural Research Center, Awassa, Ethiopia. Contaminatedknives were found to transmit the pathogen from infected to healthy plants. Disease symptoms were recorded within 15 and 21 days after inoculation on plants inoculated at 6 and 12 months after transplanting, respectively.Enset plants inoculated at 24 and 36 months after transplanting showed initial wilt symptoms 30 days after inoculation. Xanthomonas campestris pv. musacearum (Xcm) isolates were observed to survive in the soil up to9 days. Thereafter the bacteria population reduced to a level that could not initiate infection. Xcm was also observed to survive in pruned leaf petioles and leaf sheaths for at least 3 months

Evaluation of enset clones against enset bacterial wilt

Enset (Ensete ventricosum Welw. Cheesman) is an important food crop for over 20% of the Ethiopian population living in the southern and southwestern parts of the country. Enset farmers commonly grow combinations of clones in fields, but each clone is grown for its specific use. A large number of enset clones collected from the Sidama, Gurage, Kembata Tembaro and Hadyia zones were assessed for resistance/tolerance to enset bacterial wilt, Xanthomonas campestris pv. musacearum (Xcm) at the Awassa Agricultural Research Center, Awassa in Ethiopia, during the period 1994 to 2000. In addition, some enset clones that were reported by farmers and researchers as tolerant to Xcm were evaluated during the same period. The objective of the study was to screen field-grown enset clones collected from different zones of southern Ethiopia, for reaction against the wilt. AllXcm inoculated enset clones in each of the experiments developed disease symptoms to various intensity levels during the first 45 days after inoculation. However, several enset clones showed relative tolerance to the disease. The enset clones ‘Astara’, ‘Buffare’, ‘Geziwet 2’, ‘Gulumo’ and ‘Kullo’ showed 100% disease symptoms at 30days after inoculation and could, hence, be used as susceptible checks in future screening trials. Disease symptoms were observed on ‘Mezya’, ‘Hiniba’, ‘Sorpie’ and ‘Sigezasarum’, between 21 and 75 days after inoculation. However, some plants resumed normal growth at 90 days after inoculation. The enset clones that showed a resistant and/or tolerant reaction to the wilt pathogen should be further evaluated against a large number of Xcm isolates under greenhouse and field conditions

Regulatory T cells in erythema nodosum leprosum maintain anti-inflammatory function

Background The numbers of circulating regulatory T cells (Tregs) are increased in lepromatous leprosy (LL) but reduced in erythema nodosum leprosum (ENL), the inflammatory complication of LL. It is unclear whether the suppressive function of Tregs is intact in both these conditions. Methods A longitudinal study recruited participants at ALERT Hospital, Ethiopia. Peripheral blood samples were obtained before and after 24 weeks of prednisolone treatment for ENL and multidrug therapy (MDT) for participants with LL. We evaluated the suppressive function of Tregs in the peripheral blood mononuclear cells (PBMCs) of participants with LL and ENL by analysis of TNFα, IFNγ and IL-10 responses to Mycobacterium leprae (M. leprae) stimulation before and after depletion of CD25+ cells. Results 30 LL participants with ENL and 30 LL participants without ENL were recruited. The depletion of CD25+ cells from PBMCs was associated with enhanced TNFα and IFNγ responses to M. leprae stimulation before and after 24 weeks treatment of LL with MDT and of ENL with prednisolone. The addition of autologous CD25+ cells to CD25+ depleted PBMCs abolished these responses. In both non-reactional LL and ENL groups mitogen (PHA)-induced TNFα and IFNγ responses were not affected by depletion of CD25+ cells either before or after treatment. Depleting CD25+ cells did not affect the IL-10 response to M. leprae before and after 24 weeks of MDT in participants with LL. However, depletion of CD25+ cells was associated with an enhanced IL-10 response on stimulation with M. leprae in untreated participants with ENL and reduced IL-10 responses in treated individuals with ENL. The enhanced IL-10 in untreated ENL and the reduced IL-10 response in prednisolone treated individuals with ENL was abolished by addition of autologous CD25+ cells. Conclusion The findings support the hypothesis that the impaired cell-mediated immune response in individuals with LL is M. leprae antigen specific and the unresponsiveness can be reversed by depleting CD25+ cells. Our results suggest that the suppressive function of Tregs in ENL is intact despite ENL being associated with reduced numbers of Tregs. The lack of difference in IL-10 response in control PBMCs and CD25+ depleted PBMCs in individuals with LL and the increased IL-10 response following the depletion of CD25+ cells in individuals with untreated ENL suggest that the mechanism of immune regulation by Tregs in leprosy appears independent of IL-10 or that other cells may be responsible for IL-10 production in leprosy. The present findings highlight mechanisms of T cell regulation in LL and ENL and provide insights into the control of peripheral immune tolerance, identifying Tregs as a potential therapeutic target

Evaluation of Enset clones against Enset bacterial wilt

Enset ( Ensete ventricosum Welw. Cheesman) is an important food crop for over 20% of the Ethiopian population living in the southern and southwestern parts of the country. Enset farmers commonly grow combinations of clones in fields, but each clone is grown for its specific use. A large number of enset clones collected from the Sidama, Gurage, Kembata Tembaro and Hadyia zones were assessed for resistance/tolerance to enset bacterial wilt, Xanthomonas campestris pv. musacearum (Xcm) at the Awassa Agricultural Research Center, Awassa in Ethiopia, during the period 1994 to 2000. In addition, some enset clones that were reported by farmers and researchers as tolerant to Xcm were evaluated during the same period. The objective of the study was to screen field-grown enset clones collected from different zones of southern Ethiopia, for reaction against the wilt. All Xcm inoculated enset clones in each of the experiments developed disease symptoms to various intensity levels during the first 45 days after inoculation. However, several enset clones showed relative tolerance to the disease. The enset clones &apos;Astara&apos;, &apos;Buffare&apos;, &apos;Geziwet 2&apos;, &apos;Gulumo&apos; and &apos;Kullo&apos; showed 100% disease symptoms at 30 days after inoculation and could, hence, be used as susceptible checks in future screening trials. Disease symptoms were observed on &apos;Mezya&apos;, &apos;Hiniba&apos;, &apos;Sorpie&apos; and &apos;Sigezasarum&apos;, between 21 and 75 days after inoculation. However, some plants resumed normal growth at 90 days after inoculation. The enset clones that showed a resistant and/or tolerant reaction to the wilt pathogen should be further evaluated against a large number of Xcm isolates under greenhouse and field conditions.Enset ( Ensete ventricosum Welw. Cheesman) est une importante récolte de nourriture pour plus de 20% de la population éthiopienne qui habite dans le Sud et les parties du Sud-Ouest du pays. Les agriculteurs d&apos;Enset dévéloppent ordinairement des combinaisons de clones dans les champs, mais chaque clone sont grandis pour son usage spécifique. Plusieurs clones d&apos;enset recueilli du Sidama, Gurage, Kembata Tembaro et les zones de Hadyia ont été évalué pour la résistance tolérance à enset bactérien flanche, Xanthomonas campestris pv. Musacearum (Xcm) à l&apos;Awassa le Centre de Recherche Agricole, Awassa dans Ethiopie, pendant la période 1994 à 2000. Par ailleurs, quelque enset clone cela ont été rapporté par les agriculteurs et les chercheurs comme tolérant à Xcm ont été évalué pendant la même période. L&apos;objectif de l&apos;étude était de trier les clones d&apos;enset champ-grandis recueillis des zones différentes du sud d&apos;Ethiopie, pour la réaction contre le flanche. Tout Xcm a vacciné les clones d&apos;enset dans chacune des expériences ont développé les symptômes de maladie aux divers niveaux d&apos;intensité pendant le premier 45 jours après l&apos;inoculation. Cependant, plusieurs enset clone la tolérance relative montrée à la maladie. L&apos;enset clone « Astara », « Buffare », , « Gulumo » et « Kullo » ont montré 100% symptômes de maladie à 30 jours après l&apos;inoculation et peut, donc, est utilisé comme les contrôles susceptibles dans avenir trier les procès. Les symptômes de maladie ont été observés sur « Mezya », « Hiniba », « Sorpie » et « Sigezasarum », entre 21 et 75 jours après l&apos;inoculation. Cependant, quelques plantes ont repris la croissance normale à 90 jours après l&apos;inoculation. L&apos;enset clone a montré la réaction tolérante à un et/ou résistant au flanche le pathogène devrait être plus évalué contre plusieurs Xcm isole sous les conditions de serre et champ

Mechanical transmission and survival of bacterial wilt on enset

The transmission of enset bacterial wilt with contaminated knives and the survival of the causal agent in soil and enset plant debris was studied at the Awassa Agricultural Research Center, Awassa, Ethiopia. Contaminated knives were found to transmit the pathogen from infected to healthy plants. Disease symptoms were recorded within 15 and 21 days after inoculation on plants inoculated at 6 and 12 months after transplanting, respectively. Enset plants inoculated at 24 and 36 months after transplanting showed initial wilt symptoms 30 days after inoculation. Xanthomonas campestris pv. musacearum (Xcm) isolates were observed to survive in the soil up to 9 days. Thereafter the bacteria population reduced to a level that could not initiate infection. Xcm was also observed to survive in pruned leaf petioles and leaf sheaths for at least 3 months.La transmission d&apos;enset bactérien flanche avec les couteaux contaminés et la survie de l&apos;agent causal dans le sol et de débris de plante d&apos;enset a été études à l&apos;Awassa le Centre de Recherche Agricole, Awassa, Ethiopie. Les couteaux infectés été trouvésdangereux pour transmettre le pathogène de plantes infectés aux plantes saines. Les symptômes de maladie ont été enregistrés dans 15 à 21 jours après l&apos;inoculation sur les plantes vaccinées à 6 et 12 mois après avoir transplanté. Plante d&apos;Enset vacciné à 24 et 36 mois après avoir transplanté amontré les symptômes initiaux 30 jours après l&apos;inoculation. Xanthomonas campestris pv. musacearum (Xcm) isolé ont été observé vivant dans le sol jusqu&apos;à 9 jours. Par la suite la population de bactéries a réduit à un niveau qui ne pourrait pas causer l&apos;infection. Xcm a été aussi observé pour vivant dans les petioles de feuille élagué et les gaines de feuille pour au moins 3 mois