Pneumonia and respiratory failure from swine-origin influenza A (H1N1) in Mexico.
BACKGROUND
In late March 2009, an outbreak of a respiratory illness later proved to be caused by novel swine-origin influenza A (H1N1) virus (S-OIV) was identified in Mexico. We describe the clinical and epidemiologic characteristics of persons hospitalized for pneumonia at the national tertiary hospital for respiratory illnesses in Mexico City who had laboratory-confirmed S-OIV infection, also known as swine flu.


METHODS
We used retrospective medical chart reviews to collect data on the hospitalized patients. S-OIV infection was confirmed in specimens with the use of a real-time reverse-transcriptase-polymerase-chain-reaction assay.


RESULTS
From March 24 through April 24, 2009, a total of 18 cases of pneumonia and confirmed S-OIV infection were identified among 98 patients hospitalized for acute respiratory illness at the National Institute of Respiratory Diseases in Mexico City. More than half of the 18 case patients were between 13 and 47 years of age, and only 8 had preexisting medical conditions. For 16 of the 18 patients, this was the first hospitalization for their illness; the other 2 patients were referred from other hospitals. All patients had fever, cough, dyspnea or respiratory distress, increased serum lactate dehydrogenase levels, and bilateral patchy pneumonia. Other common findings were an increased creatine kinase level (in 62% of patients) and lymphopenia (in 61%). Twelve patients required mechanical ventilation, and seven died. Within 7 days after contact with the initial case patients, a mild or moderate influenza-like illness developed in 22 health care workers; they were treated with oseltamivir, and none were hospitalized.


CONCLUSIONS
S-OIV infection can cause severe illness, the acute respiratory distress syndrome, and death in previously healthy persons who are young to middle-aged. None of the secondary infections among health care workers were severe.
Perez-Padilla
Rogelio
R
National Institute of Respiratory Diseases, Mexico City, Mexico. perezpad@gmail.com
de la Rosa-Zamboni
Daniela
D
Ponce de Leon
Samuel
S
Hernandez
Mauricio
M
Quiñones-Falconi
Francisco
F
Bautista
Edgar
E
Ramirez-Venegas
Alejandra
A
Rojas-Serrano
Jorge
J
Ormsby
Christopher E
CE
Corrales
Ariel
A
Higuera
Anjarath
A
Mondragon
Edgar
E
Cordova-Villalobos
Jose Angel
JA
D018806:APACHE; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000998:Antiviral Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D017758:Infectious Disease Transmission, Patient-to-Professional; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000302:isolation & purification; D007251:Influenza, Human / Q000150:complications* / Q000453:epidemiology / Q000628:therapy / Q000635:transmission; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D053139:Oseltamivir / Q000627:therapeutic use; D011024:Pneumonia, Viral / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality / Q000473:pathology; D011859:Radiography; D012128:Respiratory Distress Syndrome / Q000209:etiology; D012131:Respiratory Insufficiency / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D012189:Retrospective Studies; D055815:Young Adult
D000998:Antiviral Agents; D053139:Oseltamivir