Bronchiolitis is an inflammation of the pulmonary bronchioles  . The diagnosis is clinical and is based on signs of low respiratory infection (cough, respiratory congestion, sibilant rales, crepitations), in an infant under 2 years of age, with or without respiratory discomfort (polypnea, expiratory blockage, dyspnea, Thoracic distension)  . It is the first of all diseases of the lower respiratory tract     . The factors that favor the outbreak of the pathology are: age, season, child constitution, sex, nutrition, environment: promiscuity, smoking mo- ther, pollution. In practice, risk factors are grouped into 5 major groups for some authors   . Thus we have: the fragility of the child, life in collectivity, the smoking of the entourage, socio-economic conditions and urbanization.
Acute respiratory infections are the leading cause of mortality and morbidity in young children around the world. They account for about 25% of the causes of death in children under 5 years of age    .
A study carried out in Tunisia during the first quarter of 1999 showed that out of a population of 1340 children admitted during the period, 10% were admitted for a respiratory problem related to bronchiolitis    .
A report by the Ministry of Health published in 2011 places respiratory infections in second place of the causes of infant morbidity and third in the causes of infant mortality in the Democratic Republic of Congo   .
Numerous studies carried out in other heavens    have clearly demonstrated a relationship between the occurrence of bronchiolitis and certain risk factors. For example, a study carried out in Italy between 1999 and 2002 revealed the following observation  : the peak of the epidemic occurred in February, while the lowest prevalence was recorded in November   . A high proportion of subjects had a low birth weight and most were born prematurely. For this study, gestational age, birth order, birth weight and exposure to tobacco smoke affected the prevalence and severity of the disease     .
Our study aims to contribute to the improvement of the management of acute bronchiolitis of the infant. Specifically, our study aims to: Determine the incidence of acute bronchiolitis in our environment, the epidemiological and clinical profile of children affected, and the nutritional status of the children concerned.
2.1. Framework of Study
This work was carried out in the geographical area of the city of Lubumbashi, the second city of the DR Congo. Three hospitals have been used as a data collection site, depending on whether they organize a dedicated pediatric unit and have a high pediatric attendance rate, especially for infants under 24 months of age. Our choice has also been guided by the fact that these structures have a rationalization of care based on an expertise of doctors, specialists or accustomed to the infantile care. These are the following health facilities:
・ Jason Sendwe General Referral Hospital, a University teaching hospital (tertiary level), with a mean of 1257 children admitted per year during our study period.
・ Lubumbashi University Clinics, a University teaching hospital (tertiary level), with a mean of 602 children admitted per year during our study period.
・ Watoto Health Center, a private specialized pediatric clinic, with a mean of 2368 children admitted per year during our study period.
2.2. Type, Duration and Period of Study
This is a cross-sectional descriptive study carried out in three hospitals in the city of Lubumbashi. The study covers the period from 1st January 2013 to 31 December 2014, a two-year study period.
2.3. Population and Sampling
・ Target population
Our target population is infants living in the city of Lubumbashi.
・ Sample type and size
We conducted a sampling of convenience. A total of 321 cases of bronchiolitis were collected, as an exhaustive sample based on the inclusion and exclusion criteria described below.
・ Inclusion Criteria
This study included infants who met the following criteria:
Ø Being a resident of Lubumbashi city town;
Ø Having a lower or equal age to 24 months;
Ø Being hospitalized for bronchiolitis in one of the designed hospitals.
The diagnosis of bronchiolitis was made on the basis of the following criteria: At an age less than or equal to 24 months, developed a cold after which the clinical examination revealed the presence of sibilant rales on auscultation, with The presence of a radiograph of the thorax suggestive of bronchiolitis (horizontalization of the dimensions, widening of the intercostal spaces, trapping of air, flattening of diaphragmatic hemi-cups).
・ Exclusion Criteria
Excluded from this study were:
Ø All cases of dyspnea with sibilances can be explained e d by another cause that bronchiolitis (heart defects, ed foreign body intra-pulmonary, asthma infant, etc.)
Ø Outpatient bronchiolitis
Ø All cases missing evident clinical elements for the diagnosis of bronchiolitis, even if it was the chosen diagnosis by the examiner.
Thus, out of 8454 records examined, 418 records were suspected of bronchiolitis, but only 321 were selected according to the previous criteria.
2.4. Study Parameters
The following parameters were collected and were the subject of our study: Age (in months), Sex, Weight (in Kg), period of consultation, Residence area, reason for consultation, duration of hospitalization, evolution.
2.5. Data Collection
We used a documentary review based on hospital records and patient registers. The data were collected on the basis of a sheet prepared for this purpose and which enabled the recruitment of cases.
2.6. Data Processing and Analysis
The data were entered on a computer using the Epi-info 6.4 software, which generated descriptive aspects of the analysis, including frequency distributions. The Chi² or Fisher test made it possible to compare the proportions of the categorical variables. To find an association between a dependent variable and perceived risk factors, the odds ratio (OR) with 95% confidence limits (p < 0.05) were calculated.
For the assessment of nutritional status, the Weight for Age Z-score was calculated using the WHO ENA 2010 software. It was categorized as follows: normal Z-score between −1 and +1, Underweight with a Z-score < −1 moderately underweight with a Z-score <−2, severe underweight with a Z-score < −3.
2.7. Ethical Considerations
The essential principles related to the non-nuisance and anonymity of the patients were respected. Prior to the study, a research permit was granted by the Faculty of Medicine. Similarly, we obtained the discharge from the administration of the hospitals where the data collection was carried out.
We collected about 321 cases of bronchiolitis out of a total of 8,454 infants admitted to hospital over a two-year study period from January 2013 to December 2014 with a frequency of 3.80% (Figure 1).
Bronchiolitis occurred most from December (8.7%) until March (8.7%), and the peak was observed in February or 24.9% of the cases. This corresponds to the great rainy season in our environment.
According to this table, children from 1 to 6 months are the most vulnerable (54.80% of the cases) followed by those of 7 to 12 months (23.00%). With a median calculated at 5 months (P25 = 2, P75 = 15). With an average calculated at 7.78 ± 6.43 months; Extremes 1 month and 24 months (Table 1).
The male sex is the most affected, that is 56% of the cases and the sex ratio was estimated at 1.26 in favor of the male sex.
The communes of Kampemba and Lubumbashi are the most affected by the pathology with 43.61% and 29.60% of cases, respectively.
The prevalence of underweight was 40.6% (n = 129), distributed as follows: 17% (n = 54) of moderate malnutrition and 23.6% (n = 75) of severe malnutrition (Table 2).
This table shows a significant association between the evolution of the pathology and the history of prematurity (p = 0.00). A preterm infant is 111 times more likely to die from bronchiolitis. A significant association was then observed
Figure 1. Distribution of cases by seasonality.
Table 1. Distribution of cases by socio-demographic parameters.
Table 2. Distribution of cases according to the Weight for Age Z-score classification.
between the evolution of bronchiolitis and the presence of associated pathologies (p = 0.02). Thus, with the presence of associated pathologies, an infant is 8 times more likely to die (Table 3).
An age of less than 6 months is significantly associated with a shorter duration
Table 3. Distribution of cases according to the factors associated with the evolution of the pathology.
of stay (less than 5 days) (p = 0.00, OR = 0.2 (0.1 - 0.4)). The average length of stay is 6.04 ± 6 days.
This study has some limitations. First, the diagnosis of bronchiolitis was mainly based on the assessment of the physician in charge of the patient, which implies that a rare number of cases considered as bronchiolitis could have been other pathologies associated with dyspnea and sibilance. Secondly, our retrospective and multicentric study suffered from the lack of homogeneity of patient records, which differed from one hospital to another, and the lack of certain socio-de- mographic data, often incomplete from medical records. However, despite these limitations, the objectives of our study were reasonably achieved.
We collected about 321 cases of bronchiolitis out of a total of 8454 infants: a frequency of 3.80%. This frequency is lower than that found in 1989 by Wembonyama as an hospital incidence in Lubumbashi, which was then at 11.3%  . This frequency is also lower than that of Bobossi with 20.9%  , Tall with 21.7%  , Adonis with 14.6%  or Sawadogo with 11.6%  .
This relatively low frequency is explained by the fact that we have focused on hospitalized cases, therefore potentially serious. Therefore, moderate to mild cases may have been treated on an outpatient basis and have not been collected in our series. Nevertheless, it is encouraging to note a possible improvement in hospital management in Lubumbashi when one considers the blatant difference in frequency in the above-mentioned study of 30 years ago. On the other hand, more improvement would probably be noted if public health measures, such as RSV vaccination, were initiated.
It was noted that children aged 1 to 6 months are the most vulnerable (54.80% of the cases) followed by those of 7 to 12 months (23.00%), i.e. a median calculated at 5 months (P25 = 2, P75 = 15), the male sex is the most affected, that is to say 56% of the cases and the sex ratio was estimated at 1.26 in favor of the male sex. These figures are similar to most of the studies consulted, but there is no explanation for this fact      .
For the period, bronchiolitis occurred most from December (8.7%) until March (8.7%), and the peak was observed in the month of February 24.9% of the cases that corresponds to the rainy season in our environment. Indeed, the moisture would be favorable to the spread of RSV, the main causative agent of the bronchiolitis of the infant.
Our study shows a strong association between the evolution of the pathology and the antecedent of prematurity (p = 0.00). A preterm infant is 111 times more likely to die from bronchiolitis. There is also a significant association between the evolution of bronchiolitis and the presence of associated pathologies (p = 0.02). Thus, with the presence of associated pathologies, an infant is 8 times more likely to die.
The average length of stay is 6.04 ± 6 days. An age of less than 6 months was associated with a longer stay (more than 5 days). In one study, Bogne et al. Found an average hospital stay of 5 days. Complications were relatively lower in the series, except for cases of bacterial superinfection. Results close to ours  .
In relation to nutritional status, the prevalence of underweight is 40.6%. In Tshikaji in another DR Congo province, Musumbu et al. Have found that the histogram of Z-scores for age shows a curve deviated toward negative values, with a Z-weight-for-mean score of −1.31 ± 1.29. And in its series, 40.2% of children had good nutritional status, compared with 28.3% who were malnourished. No children were overweight  . Meanwhile, According to the findings of a study of acute respiratory infections and nutritional status in children aged 0 - 5 years with in University Clinics of Lubumbashi, Democratic Republic of Congo  , it appears that in fact nearly 70% of children have precarious nutritional status and nutritional status, they had 41.2% of cases of ARI with proven malnutrition. This highlights the probable role of poor nutritional status that may favor the occurrence or perpetuation of bronchiolitis in infants.
This study shows that bronchiolitis constitutes a real health issue for the child, given its frequency. This highlights the importance of integrating an RSV vaccine into the vaccine schedule. Taking action on known risk factors, including prematurity and a globally deleterious state of health by the coexistence of associated pathologies, would help to reduce this frequency.
 Broek, I., Harris, N., Henkens, M., Mekaoui, H., Palma, P.P., Szumilin, E. and Grouzard, V. (2010) Clinic and Therapeutic Guide for Curative Programs in Hospitals and Clinics. Doctors without Borders, Marsh, 64.
 Okoko, J.B., Wesumperuma, H.L. and Hart, C.A. (2001) The Influence of Prematurity and Low Birthweight on Transplacental Antibody Transfer in Rural West African Population. Tropical Medicine & International Health, 6, 529-534.
 McIntosh, K. (1991) Pathogenesis of Severe Acute Respiratory Infections in Developing World: Respiratory Syncytial Virus and Parainfluenza Viruses. Reviews of Infectious Diseases, 13, 492-500.
 Zouari, A., Smaoui, H., Brun, D., Njampeko, E., Sghaier, S., Zouari, E. and Kachrid, A. (2012) Prevalence of Bordetella pertussis Infections in Tunisian Hospitalized Infants: Results of 4-Year Prospective Study. Diagnostic Microbiology and Infections Disease, 72, 303-317.
 Bobossi, S.G., Bangue, C. and Mobima, T. (2004) Eidemiological, Clinical Ant Therapeutic of Acute Bronchiolitis in Infants in the Pediatric Complex of Bangui (Central African Republic). Medicine d’Afrique Noire, 2004, 217-222.
 Musumbu, M.T., Mulowa, M.B., Mbuyi, J.P. and Beya, K.B. (2015) Study of Some Epidemiological, Clinical, Nutritional and Therapeutic Aspects of Bronchiolitis in Children Hospitalized in Bon Berger Hospital in Tshikaji, Kasai Occidental, RD Congo. Revue Medicale des grands Lacs/Great Lakes, 4, 41-45.
 American Academy of Pediatrics (AAP) Subcommittee on Diagnosis and Management of Bronchiolitis (2006) Diagnosis and Management of Bronchiolitis. Pediatrics, 118, 1774-1793.
 Bogne, J.B., Chiabi, A., Yatchet Tchatat, D., Nguefack, S., Mah, E., Tchokoteu, P.F and Mbonda, E. (2013) Acute Bronchiolitis in Infant Less than 24 Months in Yaoundé (About 296 Cases). Original Article, Yaoundé, 1.
 Kabamba, N.L., Mbombo, D., Nduwa, K., Abasiko, M.A., Kaj, K.N., Ngolomba, J., Kakez, N.D. and Luboya, N.O. (2014) Acute Respiratory Infection and Nutritional Status in Children 0-5 Years: University Clinics of Lubumbashi, DR Congo. Pan African Medical Journal, 19, 393.
 Bakonde, B., Tatagan, K., Kessie, K., Kafechina, A.B.L., Assimadi, K., Paupe, J. and Scheinman, P. (1998) Hospital Epidemiology of Acute Lower Respiratory Infectionsr in Togolese Children. Médecine d’Afrique Noire, 45, 7.
 Guedehoussou, T. (1990) Acute Respiratory Infections in Children in Togo; Epidemiological, Clinical and Therapeutic Aspects: About a Prospective Study of 530 Cases Observed in Pediatrics Department of CHU-TOKOIN Lomé. Medical Thesis, Lomé.
 Tall, F.R., Valian, A., Curtis, V., Traore, A., Nacro, B., Cousens, S., et al. (1994) Acute Respiratory Infections in Pediatric Hospital of Bobo Dioulasso (Burkina Faso). Archives Francaises De Pediatrie, 1, 249-254.
 Adonis L.V., Tanoh, F.A., Ngoan, A.M., Camara, R., Kouadio, A.V., Amangoua, E., et al. (1994) General Profile of Lower Respiratory Diseases Children in CHU Yopougon. Publications médicales Africaines, 129, 29-34.
 Sawadogo, S.A., Sanou, I., Kam, K.L., Reinhardt, T.M., Koueta, F., Dao, L., et al. (1997) Acute Bronchiolitis of Infants in Pediatric Hospital in Burkina Faso. Annales de pédiatrie, 44, 493-499. Expansion Scientifique Publications