Influenza and other respiratory viruses among febrile children with and without respiratory symptoms in Tanzania
Abstract number: P1219
D'Acremont V., Cherpillod P., Kilowoko M., Kyungu E., Philipina S., Sangu W., Kahama-Maro J., Kibatala P., Alamo L., Lengeler C., Genton B., Kaiser L.
Objectives: Viral respiratory tract infections are the most frequent cause of febrile illnesses in infants and young children in industrialized countries but few studies have been conducted in Africa, especially in outpatients. To assess the contribution of viral infections to febrile episodes in children attending an outpatient clinic, we investigated the prevalence of common respiratory viruses among children with and without respiratory symptom/sign(s) in a rural and urban setting in Tanzania.
Methods: All consenting children aged 2 months to 10 years with temperature >38°C were recruited between Apr-Dec 2008. Medical history and clinical examination were done and nasal/throat swabs taken for viral real-time PCR. Ct values were used to provide semi quantitative viral loads. X-ray was performed when IMCI criteria for clinical pneumonia were met. Other investigations were also undertaken to find a precise etiology of the fever episode with a probability level based on a pre-defined algorithm.
Results: 1005 children were recruited. 643 (64%) had at least one respiratory symptom/sign (RSS): 507 children had an acute respiratory infection (ARI) as primary diagnosis (high probability) (63% URTI, 20% clinical pneumonia with normal Xray, 8% bronchiolitis, 6% pneumonia confirmed by X-ray, 3% pneumonia with no Xray done) and 136 children had ARI as secondary diagnosis. 362 children had no RSS. Based on preliminary viral analysis and excluding picornaviruses, the proportion of children infected with at least one respiratory virus was 40% for children with ARI as primary diagnosis, 21% for children with ARI as secondary diagnosis and 15% for children without RSS. The proportion of children with picornavirus was the same in the 3 groups (36%, 35% and 33% respectively). The proportion of children with double infection was 15%, 5% and 6% respectively.
The proportion of children with presumably high viral titers (Ct < 25) were similar between the 3 groups, except for influenza A where more children with ARI as primary diagnosis than ARI as secondary diagnosis had high titres (see graph).
Conclusion: In these African children with febrile illnesses the prevalence of influenza A and B and of other respiratory viruses was higher than expected, especially in children without any respiratory symptom or sign. This latter observation suggests that these viruses may cause fever episodes without obvious respiratory manifestations.
Graph. Proportion of febrile children infected with each respiratory virus stratified by the absence/presence of ARI and/or RSS. Left column: ARI as primary diagnosis; Middle column: ARI as secondary diagnosis; Right column: no RSS.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
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