It is about a descriptive prospective study carried out from January to December 2018 (12 months).

This descriptive study was conducted at the pediatric department of Hôpital du Mali and at the Community-based Health Center of Yirimadio.

This study focused on patients in all age-groups of both sexes referred to our service by Hôpital du Mali pediatric department (from 6 months to 15-years old) and the Yirimadio Community-based Health Center (children and adults) for lower respiratory infection.

Variables studied were of four kinds:

· socio-demographic data (age, gender);

· clinical data (cough, temperature, dyspnea, breath sounds);

· chest x-ray results (syndromes: bronchial, alveolar, interstitial, pleural, mediastinal); and

· biology results (hemogram, PCR).

Data collection was done using an individual survey sheet on which socio-epidemiological, clinical and x-ray data was recorded. Data was entered and analyzed using SPSS version 22.0 software. Word processing was done with Microsoft Word 2013 software. Proportion comparisons were made by Chi-square test and significance level was set at p < 0.005.

The hospital officials’ authorization and that of children’s parents were to be obtained to use the data. Patient’s anonymity and confidentiality were respected in accordance with medical ethics rules and the legislation on biomedical and scientific research. There is no conflict of interest in this study. Data integrity was respected.

The 0 - 5 age group was the most represented (64.5%). Females were slightly predominant (50.6%) with a sex ratio of 0.97 (Table 1).

Cough was the most frequent clinical sign in our series (98.7%) followed by fever (58.9%) and crackles (28.5%) (Figure 1).

The standard chest X-ray was pathological in 70% of our patients. Bronchitis was present in 75.4% of cases (Table 2).

The majority of our patients (53.9%) had an abnormal white blood cell count. These were hyperleukocytosis in 35.5% and leukopenia in 18.4%. PCR was positive in 83.9% of our patients. It revealed a co-infection in 52.5% of patients. Virus/bacteria co-infection was the most frequent (46.8%) (Table 3).

Streptococcus pneumonia was the most represented bacterium with a frequency of 87.6% followed by Staphylococcus aureus (24.9%) (Figure 2).

Human rhinovirus (HRV) was the most represented virus with 17%, followed by influenza A and B virus (FLU A&B) (7%) and human para influenza virus (7%) (Figure 3).

The combination of Streptococcus pneumoniaa and human rhinovirus was the most represented type of co-infection with 7.5% (Figure 4).

Other: COV 229 (0.2%), FLU A&B (0.2%), FLU A&B + EV (0.2%), H1N1 + HRV (0.2%), H1N1 + FLU A&B (0.2%), HAdV + EV (0.2%), HAdV + H1N1 (0.2%), HAdV + HBoV (0.2%), HAdV + HBoV + HRV (0.2%), HAdV + NL63 + HRV (0.2%), HBoV + EV (0.2%), HboV + FLU A&B (0.2%), HCOV 229E + HPIV (0.2%), HCOV 229E + HRV (0.2%), HCOV NL63 + HAdV(0.2%), HCOV NL63 + HMPVA&B (0.2%), HCOV NL63 + HPIV (0.2%), HCOV229E + HAdV + EV (0.2%), HCOVOC43 + HRV (0.2%), HMPVA&B + FLU A&B, + H1N1 + EV(0.2%), HMPVA&B + HCOV HKU1 (0.2%), HMPVA&B + HPeV (0.2%), HMPVA&B + HRSVA&B + HPIV (0.2%), HPIV + HAdV + HBoV (0.2%), HPIV + HAdV + HRV (0.2%), HPIV + HBoV (0.2%), HPIV + HBoV + EV (0.2%), HRSVA + EV (0.2%), HRSVA + HAdV (0.4%), HBoV + H1N1 (0.4%), HCOV NL63 (0.4%), HMPVA&B + EV (0.4%), HMPVA&B + HBoV (0.4%), HMPVA&B + HBoV + HRV (0.4%), HMPVA&B + HPIV (0.4%), HPIV + HAdV (0.4%), HBoV + FLU A&B (0.7%), HCOV HKU1 (0.7%), HMPVA&B + HAdV (0.7%), HPIV + EV (0.9%), HAdV + HRV (1.1%), HBoV (1.1%), HBoV + HRV (1.3%), EV (1.5%), HAdV (1.5%), HRSVA (1.9%).

Figure 3. Distribution of patients by virus type.

Other: FLUB + EV (0.2%), FLU A&B + HBoV (0.2%), H1N1 + HRV (0.2%), HBoV + HRV (0.2%), HCOV229E + HAdV + EV (0.2%), HMPVA&B + HBoV (0.2%), HMPVA&B + HBoV + HRV (0.2%), HMPVA&B + HCOV HKU1 (0.2%), HPIV4 + HRV (0.2%), HRSVA + HAdV, S.aur + HAdV (0.2%), S.aur + HCOV 229E + HPIV (0.2%), S.aur + HCOV NL63 + HPIV, S.aur + HMPVA&B (0.2%), S.aur + HMPVA&B + HAdV (0.2%), S.aur + HMPVA&B + HRSVA&B + HPIV (0.2%), S.aur + HMPVAB + HPIV (0.2%), S.aur + HPIV (0.2%), S.aur + HPIV + HBoV (0.2%), S.pneu + C.pneu (0.2%), S.pneu + COV 229 (0.2%), S.pneu + FLU A&B + H1N1(0.2%), S.pneu + FLU A&B + HIB (0.2%), S.pneu + HAdV + EV (0.2%), S.pneu + HAdV + H1N1 (0.2%), S.pneu + HAdV + HBoV (0.2%), S.pneu + HAdV + HBoV + HRV (0.2%), S.pneu + HAdV + NL63 + HRV (0.2%), S.pneu + HCOV 229E + HRV, S.pneu + HCOV HKU1 (0.2%), S.pneu + HCOV NL63 + HAdV (0.2%), S.pneu + HCOVOC43 + HRV, S.pneu + HIB + H1N1 (0.2%), S.pneu + HIB + HRV, S.pneu + HMPVA&B + EV, S.pneu + HMPVAB (0.2%), S.pneu + HMPVAB + EV, S.pneu + HMPVAB + H1N1 + EV + FLU A&B (0.2%), S.pneu + HMPVAB + HAdV, S.pneu + HMPVAB + HBoV (0.2%), S.pneu + HMPVAB + HPeV, S.pneu + HPIV + HAdV, S.pneu + HPIV + HAdV + HBoV, S.pneu + HPIV + HBoV + EV, S.pneu + HPIV + HRV + HIB (0.2%), S.pneu + HPIV + HAdV (0.2%), S.pneu + HRSVA + EV (0.2%) (0.2%), S.pneu + S.aur + FLU A&B + HBoV (0.2%), S.pneu + S.aur + H1N1 (0.2%), S.pneu + S.aur + HAdV (0.2%), S.pneu + S.aur + HAdV + HRV (0.2%), S.pneu + S.aur + HBoV + EV (0.2%), S.pneu + S.aur + HMPVA&B + HBoV + HRV (0.2%), S.pneu + S.aur + HPIV + HAdV + HRV (0.2%), S.pneu + S.aur + HPIV + HRV (0.2%), S.pneu + S.aur + HPIV3 + HRV (0.2%), S.pneu + S.aur + HPIV4 + EV, S.pneu + S.aur + HRSVA&B (0.2%) (0.4%), S.aur + H1N1, S.pneu + C.pneu + HPIV, S.pneu + FLUB + HBoV (0.4%), S.pneu + HBoV, S.pneu + HBoV + H1N1 (0.4%), S.pneu + HIB + HMPVA&B (0.4%), S.pneu + S.aur + HPIV (0.4%), FLUB + HIB (0.7%), S.aur + FLU A&B (0.7%), S.pneu + EV (0.7%), S.pneu + HAdV (0.7%), S.pneu + HPIV + EV (0.7%), S.pneu + HAdV + HRV (0.9%), S.pneu + HIB (0.9%), S.pneu + HPIV + HRV (0.9%), S.pneu + S.aur + FLU A&B (0.9%), S.aur + HRV (1.1%), S.pneu + HBoV + HRV (1.1%), S.pneu + HRSVA (1.1%).

Figure 4. Distribution of patients by type of co-infection.

From January to December 2018, 37,950 patients consulted in the 2 facilities among whom we diagnosed 453 cases of acute lower respiratory infection meeting our inclusion criteria i.e. a frequency of 1.19%. Our frequency was similar to that of Chen et al. [12] who reported a frequency of 1.4% in children in displacement camps. It was lower than that of Kabamba et al. [13], Yoseph Alameh [14] and Nzamé et al. [15] who respectively recorded frequencies of 26.1%, 20.6% and 10.9% among children.

· Age

The majority of patients in our series were children, i.e. a proportion of 80.6%. Children under 5 years of age were the most represented with a frequency of 64.5%, followed by children [5 - 9 years] (10.4%) and children [10 - 15 years] (5.7%) for an average of 9.627 ± 15.228 years and extremes of 1 month to 78 years.

Our result was comparable to the data in the literature (pneumo) [16] [17] [18] [19] and to that of Chabane M [4] in 2016 who reported a high representation of the youngest (Newborn and Infant) 67%, followed by small children (16%) and older children (13.8%).

This is probably due to organic factors, the immaturity of their immune system and nutritional status, or to the fact that young people and adults opt for self-medication as a first choice for this type of infection.

· Gender

There was no significant difference between the two sexes in our study with a sex ratio of 0.97 in favour of women. However, most African authors have observed a predominance of males in their studies, notably Nzamé [15], Kabamba [13] and Nagoan et al. [20], who reported sex ratios of 2 and 1.2 respectively in favour of boys. These data would indicate that gender is not an important risk factor in lower respiratory tract infections.

In our series, cough was observed in almost all our patients (98.7%). It was associated with fever in 58.9% of our patients, with sibilant rales in 28.5%, with crepitus in 25.6% and with dyspnoea in 15%. Our results were similar to the data in the literature [21] [22] [23] [24] and those reported by most authors. In the study by Chabane M [4], the main signs were fever, respiratory discomfort and cough in 65.5%, 15.9% and 13.8% of cases respectively. However, Nzamé et al. [15] observed fever in 94.4% and cough in 87.5%.

The standard chest X-ray performed in our patients was pathological in 70% of them, far superior to the results of Bach et al. [25], and Mwananyanda et al. [26] who respectively obtained 42% and 40.5% of pathological chest X-ray in patients with lower respiratory infections in their studies.

These were bronchitis in 75.4% of cases, pneumonia in 13.5% of cases and bronchopneumonia in 12.3% of cases. Our data are close to those of Guittet et al. [27] who found a high frequency of bronchitis in 38.4% of the patients in their study followed by pneumonia (11.9%). This is different from Bach et al. [25] who reported bronchoalveolar syndrome in 46% of patients and pneumonia in 4%. They are also different from those of Nagoan et al. [20] who found, in order of frequency, alveolar syndrome (70.3%) and bronchoalveolar syndrome (29.7%).

The majority of our patients (53.9%) had an abnormal white blood cell count. These were hyperleukocytosis in 35.5% and leukopenia in 18.4%. This result was close to that of Odièvre [28] who found hyperleukocytosis in one of three subgroups in a paediatric study consisting of three subgroups.

PCR came back positive in 83.9% of our patients. Our result was close to that of Koenig et al. [7] who observed a positivity rate of 83% in their patients. It was slightly lower than that of Berrajah et al. [29] who had a positive PCR in 86.7% of the patients in their series. However, it was higher than that of Appak et al. [30] who found a frequency of 58.7% in their study.

PCR revealed co-infection in the majority of our patients (52.5%), bacterial infection in 16.1% and viral infection in 15.2%. This frequency was higher than that of Berrajah et al. [29] and Appak et al. [30], who found frequencies of 40% and 10.2% respectively in their series.

Virus/bacteria co-infection was the most frequent (46.8%) while Appak et al. [30]. observed a predominance of the viral combination in their study. It was mostly a combination of Streptococcus pneumoniaa and human rhinovirus (7.5%) in contrast to that reported by Appak et al. [30]. who frequently detected the rhinovirus/enterovirus combination in their series.

The pathogens isolated in order of frequency were Streptococcus pneumoniaa (87.6%) followed by Staphylococcus aureus (24.9%) and human rhinovirus (17%). Our data differ from those of Heather Zar et al. [31] who reported a predominance of Bordetella pertussis (OR 11-08, 95% CI 1-33-92-54), followed by respiratory syncytial virus (8-05, 4-21-15-38) and influenza virus (4-13, 2-06-8-26) in their study of pneumonia in children in South Africa. This differed from Mwananyanda et al. [26] who found in their Zambian series a high frequency of respiratory syncytial virus [26.1%, 95% credibility interval (CIr) 17.0 - 37.7], Mycobacterium tuberculosis (12.8%, 95% CIr 4.3 - 25.3) and human metapneumovirus (12.8%, CIr 6.1 - 21.8) among children with pneumonia.

In our sample the viral causes were dominated by human rhinovirus (17%), followed by influenza A and B virus (7%) and human para influenza virus (7%). This result is close to that of Appak et al. [30], who isolated rhinovirus/enterovirus (36.2%) followed by respiratory syncytial virus (19%) and influenza A/B virus (14.7%).

This is different from Berrajah et al. [29] who found a high frequency of respiratory syncytial virus (42.7%) followed by rhinovirus (32.9%) and adenovirus (28.5%).

Our study was faced with certain limitations and difficulties, which were mainly the loss of patients due to breakdowns of the X-ray machines and strikes of the hospital doctors.