It was about a descriptive cross-sectional study with prospective data collection that had been carried out over a period of 2 months ranging from 1st April to May 31, 2024 in the Pediatrics department A of the National Hospital of Zinder.

The study population consisted of all children 0 - 5 years old admitted to the pediatrics department A of the HNZ.

All infants aged 0 - 24 months with a diagnosis of acute bronchiolitis were included in the study.

This study did not include:

These parameters have been explored:

The data was analyzed and processed with the software Epi Info7.2.6.0 Regarding the descriptive part, qualitative variables were expressed in frequencies, quantitative variables in means ± standard deviation. The link between qualitative variables was estimated using Pearson’s Chi² test.

The anonymity of patients was respected and the informed consent of their parents had been obtained.

During the study period, 1048 children were hospitalized in Pediatrics for various pathologies, including 535 cases of acute bronchiolitis (51%).

The socio-demographic aspects of patients are represented in Table 1 . The average age was of 10.40 months ± 6.91 with extremes of 1 and 24 months. Children aged 3 to 11 months were the most affected, with 52.90% of cases (n = 283). The male sex predominated in 62.06% of cases with a sex ratio of 1.6. The patients came essentially from the urban environment in 98.50% of cases (n = 527). They were admitted directly to the hospital in 62.57% of cases (n = 112). The average age of the patients’ mothers was 27.30 years old with extremes of 17 and 44 years. These were schooled about 84.92% of cases (n = 152), with a level socio-economic means about 47.49% of cases (n = 254).

Table 2 represents the personal and family histories of patients. The infants were up to date with their vaccinations according to the schedule of the expanded vaccination program (PEV) of Niger in 68.41% cases (n = 366). Breastfeeding mixed was practiced about 59.63% cases (n = 319), breastfeeding excluded about 28.78% (n = 154) and breastfeeding artificial about 11.59% cases (n = 62). Food diversification was poorly conducted in 50.84% of cases (n = 271). A history of congenital heart disease, sickle cell disease and asthma was found in infants in 2.80% (n = 15), 19.25% (n = 103) and 1.50% (n = 8) of cases respectively. Asthma, diabetes and atopy were the most found family histories in respectively 49.34% (n = 264), 37.95% (n = 203) and 6.35% cases (n = 34).

*Others: High blood pressure, sickle cell disease.

Respiratory distress with 40.19% (n = 215), fever 16.63% (n = 89), the cough 12.52% (n = 67) and the breathing difficulty 30.66% (n = 164) were the most frequent reasons for admission. The patients had consulted in the three (3) first days after the onset of symptoms in 55.32% of cases (n = 296). The average time to admission was 4.22 days with extremes of 1 day and 15 days. A fever, tachycardia and polypnea were present at admission in respectively 23.56% (n = 126); 79.06% (n = 423); 70.84% (n = 379). Patients were admitted in a state of agitation in 23.18%. The main clinical signs were cough about 43.18% (n = 231), rhinorrhea 70.85% (n = 379), the ronchi 35.33% (n = 189), crackling rattles 26.54% (n = 142) the sibilant rales 24.11% (n = 129), the signs of struggle 14.02% (n = 75) and polypnea 70.85% (n = 379) ( Figure 1 ). Respiratory distress was moderate in 50.28% (n = 269) infants and severe in 13.41% cases (n = 72). The pallor was found in 20.19% (n = 108). At the paraclinical level, a hyperleukocytosis and an anaemia were found in respectively 55.14% (n = 295) and 78.31% (n = 419) cases. Chest distension and interstitial syndrome pulmonary were the most common radiological findings, in 47.48% (n = 254) and 32.90% (n = 176) of cases respectively.

The aspects are represented in Table 3 . A nebulization was administered to 93.08% (n = 498) of the patients; physiotherapy respiratory 59.62% (n = 319); corticosteroid therapy 58.87% (n = 315), antibiotic therapy 21.50% (n = 115); oxygen therapy 36.44% (n = 195) and the nasal unobstruction 10.46% (n = 56). The antibiotic therapy was used in front of signs that raise fears of bacterial superinfection or particular fragility. One adjuvant treatment with paracetamol injection for the febrile episodes were used in 23.55% of cases (n = 126). The average duration residence permit was of 5.35 days with extremes of 1 and 11 days. The evolution was favourable about 93.08% (n = 498) and a rate of death of 1.12% (n = 6) was found.

In this study, a male predominance was found with a sex ratio of 1.6. This result confirms the observation that the male sex was preferentially affected in case of acute respiratory infections [3] [12] . This male predominance would be linked to the genetic predispositions making the little boy more susceptible to infections [13] . Doumbia et al. [14] to Mali in 2018 had regained a male predominance in 63% of the case. The children under 3 to 11 months were reached in 52.90% of cases. This could be explained by the immaturity of the immune system in this age group that I would expose these infants to repeated infections [15] . Banzet et al. [16] in Togo in 2015 had found a rate of 50.3% in infants from 0 - 3 months and 38.4% in 4 to 6 months. This disparity between the results would be explained by the difference between the places of study. As a result, bronchiolitis remains the infection of the lower respiratory tract read frequently in infants. Patients came mainly from urban areas with a rate of 98.50%. This result could be explained by the advantages of proximity and social benefits with free of care for children 0 - 5 years old offered by the HNZ. Magawata et al. [17] in 2017 in Niger had found respectively 90.67% of the cases from the environment urban. The patients were admitted directly to the HNZ in 79.06% against 19.44% of interim measures. This could be explained by the proximity of the HNZ to the majority of our patients whose origin is urban but also by non-compliance with the sanitary ramid linked to the free of charge of care for children aged 0 - 5 who are brought directly to the hospital without going through the integrated health centers (CSI). This factor has been found by other authors [12] [18] . Sagba et al. [18] in Benin in 2017 had found 46.6% of direct admissions compared to 53.4% of references. The socio-economic level was average in 47.49% of households. This factor had been found by other authors [14] .

Infants were up to date with their vaccinations according to the EPI Niger about 68.41% of the case. Proximity to health centers and the urban origin of our patients could be the main reasons for this vaccination coverage. This rate corroborates those of the literature [13] [19] . Breastfeeding mixed was practiced about 59.63% and exclusive breastfeeding about 28.78% cases.

A diagnosis of acute bronchiolitis is clinic. Complementary tests, notably immunofluorescence and PCR are only necessary in special situations such as to detect the first cases of an epidemic, to suspend anti-RSV immunoprophylaxis in the premature infants or to limit nosocomial infection in infants in a care unit. We will discuss only the clinical aspects of the diagnosis. The most frequently encountered reasons for admission in this study were respiratory distress (RD) and respiratory difficulty with 40.19% and 30.66% respectively. These same observations had been made in the literature [16] [20] . Patients had consulted within three (3) days after the onset of symptoms in 55.32% and in 38.70% between 4 to 7 days. This delay in consultation could be explained by self-medication or traditional treatment by mothers at home. Ly F et al. [21] in Senegal in 2017 had found 54.8% and 24.2% of patients and put respectively within 3 days and between 4 to 7 days from the beginning of the disease. A average admission time was 4.22 days with extremes of 1 - 15 days. On physical examination, fever was present in 23.56% of patients. This low rate could be explained by the routine administration of paracetamol or ibuprofen by mothers in case of fever before consultation. This rate is lower than those of the literature [3] [21] [22] . Ronchi, crackling rales and wheezing were found respectively in 35.33%; 26.54% and 24.11%. This result shows the inflammation of the alveoli and bronchioles during bronchiolitis [23] . These results are comparable to those found by Bellon et al. [15] in Benin in 2019. In this study, skin pallor was found in 20.19% of cases. In bronchiolitis, pallor reflects the severity of circulatory disorders that may occur during the disease. Patients were admitted in a state of agitation in 23.18%. This neurological disturbance was described by other authors and is explained by the installation of brutal hypoxemia and the brain tropism of the RSV [23] . About this study, the rhinorrhea was present in 70.85%. Ouédraogo et al. [12] and Doumbia et al. [24] had also reported a rhinorrhea in 79.2% and 80% of patients respectively. Signs of struggle and the hissing rants were found in respectively 14.02% and 24.11% cases. Doumbia et al. [24] and Maiga et al. [9] had Found respectively 95.5% and 96.22% of signs of struggle. In this study, the prescription of complementary examinations was not systematic, it was based on signs of severity and/or infectious risk factors. Chest X-rays showed thoracic distension in 47.48%. Other authors had also reported pathological images in bronchiolitis to the chest X-ray [21] [22] [24] . Blood count was most often normal in infants admitted for RSV bronchiolitis. However, a discreet lymphocytosis was sometimes noted. Polynucleosis or neutropenia should suggest a bacterial superinfection. In this study, hyperleukocytosis 55.14% and anemia 78.31% were reported. This high frequency of anemia in this study could be not only of origin carentielle in nutriments or infectious, but also of malaria origin because of its endemic character in Niger.

The nebulization has been used in 93.08% of our patients with essentially salted serum associated with the salbutamol. Doumbia et al. [24] used this association in all patients (100%). Other studies in the literature had shown a decrease in symptoms and the hospitalization period of 24 hours with the sessions of nebulizations [25] [26] . Physiotherapy Respiratory had been practiced about 59.62% of cases in this study. Antibiotic therapy was administered in 21.5% of patients. The frequency of bacterial superinfection during acute infant bronchiolitis could explain this antibiotic therapy. Bogne et al. [3] in Yaoundé in 2013 had used antibiotics in 91.7% of patients. Corticosteroids were used in 58.87% of patients. Other authors had reported this corticosteroid therapy in the literature [24] [27] . The mean length of hospitalization was 5.35 days with extremes of 1 and 11 days. Aubry et al. [28] in Lille in 2019 had reported a similar result with 4.37 days. The use of corticosteroids in this study could explain the decrease in hospitalization duration. The evolution was favorable in 93.08% of patients. The mortality rate was 1.12%. These results could be explained by the improvement of the technical plateau in the management of bronchiolitis especially with the availability of respiratory physiotherapy.