Respiratory viruses in patients with influenza-like illness in Senegal: Focus on human respiratory adenoviruses.
BACKGROUND
Human adenoviruses (HAdVs) are highly contagious pathogens that are associated with a wide spectrum of human illnesses involving the respiratory tract. In the present study, we investigate the epidemiologic and viral molecular features of HAdVs circulating in Senegal after 4 consecutive years of sentinel surveillance of influenza-like Illness cases.


RESULTS
From January 2012 to December 2015 swabs were collected from consenting ILI outpatients. Adenoviral detection is performed by rRT-PCR with the Anyplex™ II RV16 Detection kit (Seegene) and molecular characterization was performed using a partial hexon gene sequence. 6381 samples were collected. More than half of patients (51.7%; 3297/6381) were children of ≤ 5 years. 1967 (30.8%) were positive for HAdV with 1561 (79.4%) found in co-infection with at least one another respiratory virus. The most common co-detections were with influenza viruses (53.1%; 1045/1967), rhinoviruses (30%; 591/1967), enteroviruses (18.5%; 364/1967) and RSV (13.5%; 266/1967). Children under 5 were the most infected group (62.2%; 1224/1967; p <0.05). We noted that HAdV was detected throughout the year at a high level with detection peaks of different amplitudes without any clear seasonality. Phylogenetic analysis revealed species HAdV-C in majority, species HAdV-B and one HAdV- 4 genome type. The 9 HAdV-B species like strains from Senegal grouped with genome types HAdV-7, HAdV-55 and HAdV-11 as shown by a phylogenetic branch with a high bootstrap value of (88%).


CONCLUSIONS
In conclusion, the results of the present study suggest strong year-round HAdV activity in Senegal, especially in children up to 5 years of age. Molecular studies revealed that the dominant species in circulation in patients with ILI appears to be HAdV-C and HAdV-B species. The circulation of though HAdV-7 and HAdV-55 genome types is of note as these serotypes are recognized causes of more severe and even fatal acute respiratory infections.
Institut Pasteur de Dakar, Unité de Virologie Médicale, Dakar, Sénégal.
Mbayame Ndiaye
MN
Niang
Institut Pasteur de Dakar, Unité de Virologie Médicale, Dakar, Sénégal.
Ndeye Sokhna
NS
Diop
Institut Pasteur de Dakar, Unité de Virologie Médicale, Dakar, Sénégal.
Amary
A
Fall
Institut Pasteur de Dakar, Unité de Virologie Médicale, Dakar, Sénégal.
Davy E
DE
Kiori
Institut Pasteur de Dakar, Unité d'Epidémiologie des maladies infectieuses, Dakar, Sénégal.
Fatoumata Diene
FD
Sarr
Institut Pasteur de Dakar, Unité de Virologie Médicale, Dakar, Sénégal.
Sara
S
Sy
Institut Pasteur de Dakar, Unité de Virologie Médicale, Dakar, Sénégal.
Déborah
D
Goudiaby
Institut Pasteur de Dakar, Unité d'Epidémiologie des maladies infectieuses, Dakar, Sénégal.
Mamadou Aliou
MA
Barry
Département de Biologie Animale Faculté des Sciences et Techniques Université Cheikh Anta DIOP de Dakar, Dakar, Senegal.
Malick
M
Fall
Institut Pasteur de Dakar, Unité de Virologie Médicale, Dakar, Sénégal.
Ndongo
N
Dia
D000258:Adenovirus Infections, Human / Q000821:virology*; D000260:Adenoviruses, Human / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D036022:Capsid Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000821:virology; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007251:Influenza, Human / Q000821:virology*; D008297:Male; D008875:Middle Aged; D009975:Orthomyxoviridae / Q000235:genetics; D010802:Phylogeny; D012141:Respiratory Tract Infections / Q000821:virology*; D012675:Senegal; D017422:Sequence Analysis, DNA / Q000379:methods; D055815:Young Adult
D036022:Capsid Proteins