Pneumococcal colonization and coinfecting respiratory viruses in children under 5 years in Addis Ababa, Ethiopia: a prospective case-control study

A comprehensive understanding of the dynamics of Streptococcus pneumoniae colonization in conjunction with respiratory virus infections is essential for enhancing our knowledge of the pathogenesis and advancing the development of effective preventive strategies. Therefore, a case-control study was carried out in Addis Ababa, Ethiopia to investigate the colonization rate of S. pneumoniae and its coinfection dynamics with respiratory viruses among children under the age of 5 years. Samples from the nasopharyngeal and/or oropharyngeal, along with socio-demographic and clinical information, were collected from 420 children under 5 years old (210 cases with lower respiratory tract infections and 210 controls with conditions other than respiratory infections.). A one-step Multiplex real-time PCR using the Allplex Respiratory Panel Assays 1-4 was performed to identify respiratory viruses and bacteria. Data analysis was conducted using STATA software version 17. The overall colonization rate of S. pneumoniae in children aged less than 5 years was 51.2% (215/420). The colonization rates in cases and controls were 54.8% (115/210) and 47.6% (100/210), respectively (p = 0.14). Colonization rates were observed to commence at an early age in children, with a colonization rate of 48.9% and 52.7% among infants younger than 6 months controls and cases, respectively. The prevalence of AdV (OR, 3.11; 95% CI [1.31-8.19]), RSV B (OR, 2.53; 95% CI [1.01-6.78]) and HRV (OR, 1.7; 95% CI [1.04-2.78]) tends to be higher in children who tested positive for S. pneumoniae compared to those who tested negative for S. pneumoniae. Further longitudinal research is needed to understand and determine interaction mechanisms between pneumococci and viral pathogens and the clinical implications of this coinfection dynamics.

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.

Adoptive transfer of Regulatory T cells from burn-injured rats depressed T cell responses in the recipient sham rats (179.1)

Immunosuppression occurs after burn injury with or without septic complications. We hypothesize that CD4+CD25+ T cells (Treg) are responsible for transmitting inhibitory signals to the IL-2-producing T cells in burn related inflammatory/infectious conditions. Enriched Treg were obtained from day-3 burn rats by flow cytometry and magnetic microbead cell sorting and given intravenously to sham rats. The rats were then sacrificed day 1 and day 3 post-adoptive transfer and T cell proliferation responses were assessed by thymidine assay. The results indicated that when burn Treg were adoptively transferred to sham rats, T cell proliferation (CD4+, CD4+CD25+ and CD4+CD25-) of sham rats was significantly depressed. Furthermore, the results showed that adoptive transfer of Treg did not influence the phenotypic expression of CD4+ T cells of the recipient rats. The percentage expressions of CD25, CD11a (LFA), and CD62L of the recipient rats remained same as before adoptive transfer. Experiments are currently underway to expand these findings to burn plus septic rats. These preliminary findings however allow us to hypothesize that while burn injury alone can produce attenuated CD4+ T cell mediated responses as a result of actions of Treg; burn injury with septic complications may further cause an irreversible loss of T cell-mediated responses. The latter happening could be responsible for high morbidity and mortality in the injured host afflicted with burn plus a critical infection.

Prevalence of symptoms of asthma, rhinitis and eczema in 13- to 14-year-old children in Africa: the International Study of Asthma and Allergies in Childhood Phase III

Phase I of the International Study of Asthma and Allergies in Childhood has provided valuable information regarding international prevalence patterns and potential risk factors in the development of asthma, allergic rhinoconjunctivitis and eczema. However, in Phase I, only six African countries were involved (Algeria, Tunisia, Morocco, Kenya, South Africa and Ethiopia). Phase III, conducted 5-6 years later, enrolled 22 centres in 16 countries including the majority of the centres involved in Phase I and new centres in Morocco, Tunisia, Democratic Republic of Congo, Togo, Sudan, Cameroon, Gabon, Reunion Island and South Africa. There were considerable variations between the various centres of Africa in the prevalence of the main symptoms of the three conditions: wheeze (4.0-21.5%), allergic rhinoconjunctivitis (7.2-27.3%) and eczema (4.7-23.0%). There was a large variation both between countries and between centres in the same country. Several centres, including Cape Town (20.3%), Polokwane (18.0%), Reunion Island (21.5%), Brazzaville (19.9%), Nairobi (18.0%), Urban Ivory Coast (19.3%) and Conakry (18.6%) showed relatively high asthma symptom prevalences, similar to those in western Europe. There were also a number of centres showing high symptom prevalences for allergic rhinoconjunctivitis (Cape Town, Reunion Island, Brazzaville, Eldoret, Urban Ivory Coast, Conakry, Casablanca, Wilays of Algiers, Sousse and Eldoret) and eczema (Brazzaville, Eldoret, Addis Ababa, Urban Ivory Coast, Conakry, Marrakech and Casablanca).

Prevalence of wheeze and asthma related symptoms among school children in Addis Ababa, Ethiopia

This survey was conducted as part of the international multi-centre study to determine the prevalence of wheeze and asthma-related symptoms among school children in Addis Ababa, Ethiopia. It was conducted in June 1995. A standardized self-administered questionnaire developed by the International Study of Asthma and Allergies in Children (ISAAC) was used. The questionnaire was designed to offer a standardized epidemiological instrument to ensure comparison of results from wide range of countries. A total of 2951 children aged 13 and 14 years were enrolled into the study, of which 1393 (47.2%) were males and 1558 (52.8%) were females. Five hundred fifty seven children (18.2%) reported that they have had wheezing at least once in the last 12 months while only 84 children (2.8%) reported to have "Bronchial Asthma". One hundred eighty eight (6.4%) and 214 (7.3%) children reported sleep disturbance and limitation of speech associated with attacks, respectively. Nocturnal cough was reported by 805 (27.3%) children. Eight hundred two (27.2%) children reported exercise-induced wheeze. This study revealed that the prevalence of wheeze and other asthma related symptoms to be fairly high among school children of Addis Ababa, Ethiopia. Moreover, the majority of these children do not seem to know their problems and therefore, remain untreated. Further studies are recommended to precisely determine the prevalence of wheeze and asthma using more objective methods such as bronchial hyper-responsiveness test.