[Chronology of a pandemic: the new influenza A (H1N1) in Bogota, 2009-2010].
OBJECTIVE
Describing the behaviour of the A H1N1/09 virus related to time, age and gender in patients having suspected infection, medical health care and laboratory diagnosis.


METHODS
This was a descriptive and retrospective study of patients diagnosed as having the influenza A H1N1/09 virus between April 2009 and July 2010 by the Bogotá Public Health Laboratory.


RESULTS
The first cases of A H1N1/09 virus were confirmed since week 17, 2009; positivity increased gradually, reaching maximum expression between weeks 31-36, 2009 (43 % to 53 %) and decreased during the 37th week. The age groups most affected were 6-15 years (35.4 %) and 16-25 years (28 %) (p=0.0044); the lowest percentages were found in children aged less than 1 year (8.7 %) and people older than 65 years (7.2 %) (Chi 1.98, p=0.119). The gender ratio was similar: female (18.6 %) and male (17.6 %) (Chi 1.82, p=0.1768).


CONCLUSIONS
There was a significant increase in influenza A cases during 2009. However, this did not alter the behaviour of the endemic respiratory syncytial virus; on the other hand, the H1N1/09 subtype replaced the seasonal virus circulating amongst the population of Bogotá, similarly affecting men and women, mainly young adults. The highest prevalence of cases occurred between August and September 2009.
Laboratorio de Salud Pública, Secretaría de Salud Distrital, Bogotá DC, Colombia. lmnunez@saludcapital.gov.co
Lilian M
LM
Núñez
Diego F
DF
Aranda
Antonio C
AC
Jaramillo
Luisa F
LF
Moyano
Elkin de J
Ede J
Osorio
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003105:Colombia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D058873:Pandemics; D011159:Population Surveillance; D015995:Prevalence; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology; D012189:Retrospective Studies; D012621:Seasons; D055815:Young Adult