Burden of respiratory syncytial virus diseases among under 5 children in Sub-Saharan Africa: A systematic review and meta-analysis.

Background: Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory infections (ALRIs) in young children. To design preventive efforts in sub-Saharan Africa, a better knowledge of the true role of RSV in pediatric ALRIs is required. Therefore we conducted a systematic review and meta-analysis of case-control studies to estimate the etiological role of RSV to ALRIs in under 5 years children in sub-Saharan Africa. Methods: This study was done according to PRISMA guidelines. PubMed, EMBASE, SCOPUS, Web of Sciences databases, and Google Scholar were used to retrieve articles. STATA software version 17 was used for data analysis. The results of all the included studies were standardized to odds ratios (ORs) with accompanying 95 % confidence intervals (95 % CIs) and the pooled estimates of ORs, attributable fraction among the exposed (AFE), and population attributable fraction (PAF) were reported. The heterogeneity was assessed using Cochrane chi-square (I 2) statistics. Result: A total of 6200 cases and 4986 controls from 14 articles that fulfilled the inclusion criteria were included. The pooled prevalence of RSV among cases and controls was 23.52 % [95 % CI (20.68-26.47)] and 4.33 % [95 % CI (3.11-5.73)], respectively. The pooled OR is 7.04 [95 % CI (4.41-11.24)], which indicated a significant association between RSV and ALRI. Among ALRIs cases positive for RSV, the proportion of disease that was not attributable to the background rate (AFE) was 85.8 % [95 % CI (77.3-91.1)]. The fraction of ALRIs children that can be attributed to RSV (PAF) was 20.2 % [95 % CI (16-24.1)]. Conclusion: This study showed clear associations between RSV and ALRI hospitalization in young children in sub-Saharan Africa indicating the need for prophylactic measures against RSV in this age group.

Genetic diversity of Mycobacterium tuberculosis isolates from the central, eastern and southeastern Ethiopia.

Introduction: The population structure of Mycobacterium tuberculosis complex (MTBC) in Ethiopia is diverse but dominated by Euro-American (Lineage 4) and East-African-Indian (Lineage 3) lineages. The objective of this study was to describe the genetic diversity of MTBC isolates in Central, Eastern and Southeastern Ethiopia. Methods: A total of 223 MTBC culture isolates obtained from patients referred to Adama and Harar TB reference laboratories were spoligotyped. Demographic and clinical characteristics were collected. Results: Six major lineages: Euro-American (Lineage 4), East-African-Indian (Lineage 3), East Asian (Lineage 2), Indo-Oceanic (Lineage 1), Mycobacterium africanum (Lineage 5 and Lineage 6) and Ethiopian (Lineage 7) were identified. The majority (94.6 %) of the isolates were Euro-American and East-African-Indian, with proportions of 75.3 % and 19.3 %, respectively. Overall, 77 different spoligotype patterns were identified of which 42 were registered in the SITVIT2 database. Of these, 27 spoligotypes were unique, while 15 were clustered with 2-49 isolates. SIT149/T3_ETH (n = 49), SIT53/T1 (n = 33), SIT21/CAS1_Kili (n = 24) and SIT41/Turkey (n = 11) were the dominant spoligotypes. A rare Beijing spoligotype pattern, SIT541, has also been identified in Eastern Ethiopia. The overall clustering rate of sub-lineages with known SIT was 71.3 %. Age group (25-34) was significantly associated with clustering. Conclusion: We found a heterogeneous population structure of MTBC dominated by T and CAS families, and the Euro-American lineage. The identification of the Beijing strain, particularly the rare SIT541 spoligotype in Eastern Ethiopia, warrants a heightened surveillance plan, as little is known about this genotype. A large-scale investigation utilizing a tool with superior discriminatory power, such as whole genome sequencing, is necessary to gain a thorough understanding of the genetic diversity of MTBC in the nation, which would help direct the overall control efforts.

Viral etiologies of lower respiratory tract infections in children < 5 years of age in Addis Ababa, Ethiopia: a prospective case-control study.

BACKGROUND: Lower respiratory tract infections (LRTIs) are a major cause of morbidity and mortality in children worldwide and disproportionally affect Sub-Saharan Africa. Despite the heaviest burden of LRIs in Ethiopia, to date, no published studies have reported a comprehensive viral etiology of LRTIs among children in Ethiopia. The objective of this study was to determine and estimate the etiological contribution of respiratory viruses to LRTIs in < 5 years children in Ethiopia. METHODS: A prospective case-control study was conducted from September 2019 to May 2022 in two major governmental hospitals, St. Paul Hospital Millennium Medical College and ALERT Hospital in Addis Ababa, Ethiopia. Nasopharyngeal/oropharyngeal samples and socio-demographic and clinical information were collected from children under 5 years. A one-step Multiplex real-time PCR (Allplex™ Respiratory Panel Assays 1-3) was done to detect respiratory viruses. STATA software version 17 was used for the data analysis. We computed the odds ratio (OR), the attributable fraction among exposed (AFE) and the population attributable fraction (PAF) to measure the association of the detected viruses with LRTIs. RESULTS: Overall, 210 LRTIs cases and 210 non-LRTI controls were included in the study. The likelihood of detecting one or more viruses from NP/OP was higher among cases than controls (83.8% vs. 50.3%, p = 0.004). The multivariate logistic regression showed a significantly higher detection rate for RSV A (OR: 14.6, 95% CI 4.1-52.3), RSV B (OR: 8.1, 95% CI 2.3-29.1), influenza A virus (OR: 5.8, 95% CI 1.5-22.9), and PIV 1 (OR: 4.3, 95% CI 1.1-16.4), among cases when compared with controls. The overall AFE and PAF for RSV A were (93.2% and 17.3%), RSV B (87.7% and 10.4%) and Influenza A virus (82.8% and 6.3%), respectively. The mean CT values were significantly lower for only RSV B detected in the case groups as compared with the mean CT values of RSV B detected in the control group (p = 0.01). CONCLUSIONS: RSV, Influenza A and PIV 1 viruses were significantly associated with LRTIs in < 5 years children in Addis Ababa, Ethiopia. Therefore, we underscore the importance of developing prevention strategies for these viruses in Ethiopia and support the importance of developing and introducing an effective vaccine against these viruses.

Profile and Frequency of Mutations Conferring Drug-Resistant Tuberculosis in the Central, Southeastern and Eastern Ethiopia.

Purpose: Advances in molecular tools that assess genes harboring drug resistance mutations have greatly improved the detection and treatment of drug-resistant tuberculosis (DR-TB). This study was conducted to determine the frequency and type of mutations that are responsible for resistance to rifampicin (RIF), isoniazid (INH), fluoroquinolones (FLQs) and second-line injectable drugs (SLIDs) in Mycobacterium tuberculosis (MTB) isolates obtained from culture-positive pulmonary tuberculosis (TB) patients in the central, southeastern and eastern Ethiopia. Patients and Methods: In total, 224 stored culture-positive MTB isolates from pulmonary TB patients referred to Adama and Harar regional TB laboratories between August 2018 and January 2019 were assessed for mutations conferring RIF, INH, FLQs and SLIDs resistance using GenoType®MTBDRplus (MTBDRplus) and GenoType®MTBDRsl (MTBDRsl). Results: RIF, INH, FLQs and SLIDs resistance-conferring mutations were identified in 88/224 (39.3%), 85/224 (38.0%), 7/77 (9.1%), and 3/77% (3.9%) of MTB isolates, respectively. Mutation codons rpoB S531L (59.1%) for RIF, katG S315T (96.5%) for INH, gyrA A90V (42.1%) for FLQs and WT1 rrs (100%) for SLIDs were observed in the majority of the isolates tested. Over a 10th of rpoB mutations detected in the current study were unknown. Conclusion: In this study, the most common mutations conferring drug resistance to RIF, INH, FLQs were identified. However, a significant proportion of RIF-resistant isolates manifested unknown rpoB mutations. Similarly, although few in number, all SLID-resistant isolates had unknown rrs mutations. To further elucidate the entire spectrum of mutations, tool such as whole-genome sequencing is imperative. Furthermore, the expansion of molecular drug susceptibility testing services is critical for tailoring patient treatment and preventing disease transmission.

Plant growth-promoting rhizobacterial inoculation to improve growth, yield, and grain nutrient uptake of teff varieties.

Inoculation of plant growth-promoting rhizobacteria (PGPR) improves the growth, yield, and plant nutrient uptake, as well as rhizosphere fertility, without harming the environment and human health. This study aimed to examine the effect of either individual or consortium of PGP bacterial inoculation on the growth, yield, and grain nutrient uptake of teff varieties. Three potential PGPR strains (i.e., Pseudomonas fluorescens biotype G, Enterobacter cloacae ss disolvens, and Serratia marcescens ss marcescens) were used for this study. Field evaluation was carried out in RCBD with 5 treatments. Highly significant (P < 0.001) differences were observed among treatments for plant height (PH), panicle length (PL), number of the total spike (NTS), shoot dry weight (SDW), grain yield (GY), and straw yield (SY). There was also teff variety that significantly (P < 0.01) affects PL, SDW, and SY. However, the interaction effect of the two factors (treatment*variety) did not significantly influence teff agronomic traits and grain nutrient uptake. The highest PH (133.5 cm), PL (53.2), NTS (30.9), SDW (18.1 t/ha), SY (10.7 t/ha), and GY (2.7 t/ha) were observed on Dukem variety (Dz-01-974) inoculated with PGPR consortium. Wherein 2.2 fold increase was observed in grain yield per hectare over the control. Inoculation of PGPR consortium showed better performance in promoting plant growth, yield, and grain nutrient uptake of teff varieties compared with the individual PGP bacterial application, and PGPR consortium could be used as inoculants to enhance teff production and productivity.

Effect of low complexity regions within the PvMSP3α block II on the tertiary structure of the protein and implications to immune escape mechanisms.

BACKGROUND: Plasmodium vivax merozoite surface protein 3α (PvMSP3α) is a promising vaccine candidate which has shown strong association with immunogenicity and protectiveness. Its use is however complicated by evolutionary plasticity features which enhance immune evasion. Low complexity regions (LCRs) provide plasticity in surface proteins of Plasmodium species, but its implication in vaccine design remain unexplored. Here population genetic, comparative phylogenetic and structural biology analysis was performed on the gene encoding PvMSP3α. RESULTS: Three LCRs were found in PvMSP3α block II. Both the predicted tertiary structure of the protein and the phylogenetic trees based on this region were influenced by the presence of the LCRs. The LCRs were mainly B cell epitopes within or adjacent. In addition a repeat motif mimicking one of the B cell epitopes was found within the PvMSP3a block II low complexity region. This particular B cell epitope also featured rampant alanine substitutions which might impair antibody binding. CONCLUSION: The findings indicate that PvMSP3α block II possesses LCRs which might confer a strong phenotypic plasticity. The phenomenon of phenotypic plasticity and implication of LCRs in malaria immunology in general and vaccine candidate genes in particular merits further exploration.