An early report from newly established laboratory-based influenza surveillance in Lao PDR.
BACKGROUND
Prior to 2007, little information was available about the burden of influenza in Laos. We report data from the first laboratory-based influenza surveillance system established in the Lao People's Democratic Republic.


METHODS
Three hospitals in the capital city of Vientiane began surveillance for influenza-like illness (ILI) in outpatients in 2007 and expanded to include hospitalized pneumonia patients in 2008. Nasal/throat swab specimens were collected and tested for influenza and other respiratory viruses by multiplex ID-Tag respiratory viral panel (RVP) assay on a Luminex 100x MAP IS instrument (Qiagen, Singapore).


RESULTS
During January 2007 to December 2008, 287 of 526 (54.6%) outpatients with ILI were positive for at least one respiratory virus. Influenza was most commonly identified, with 63 (12.0%) influenza A and 92 (17.5%) influenza B positive patients identified. In 2008, six of 79 (7.6%) hospitalized pneumonia patients were positive for influenza A and four (5.1%) were positive for influenza B. Children <5 years represented 19% of viral infections in outpatients and 38% of pneumonia inpatients.


CONCLUSIONS
Our results provide the first documentation of influenza burden among patients with febrile respiratory illness and pneumonia requiring hospitalization in Laos. Implementing laboratory-based influenza surveillance requires substantial investments in infrastructure and training. However, continuing outbreaks of avian influenza A/H5N1 in poultry and emergence of the 2009 influenza A(H1N1) pandemic strain further underscore the importance of establishing and maintaining influenza surveillance in developing countries.
Vongphrachanh
Phengta
P
National Center for Laboratory and Epidemiology, Bangkok, Thailand.
Simmerman
James M
JM
Phonekeo
Darouny
D
Pansayavong
Vimatha
V
Sisouk
Thongchanh
T
Ongkhamme
Somvay
S
Bryce
Gary T
GT
Corwin
Andrew
A
Bryant
Juliet E
JE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D019411:Clinical Laboratory Techniques / Q000379:methods*; D003140:Communicable Disease Control / Q000458:organization & administration*; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology*; D007812:Laos / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx / Q000821:virology; D015995:Prevalence; D018571:Sentinel Surveillance; D055815:Young Adult