Clinical profile of pneumonia and its association with rain wetting in patients admitted at a tertiary care institute during pandemic of influenza A (H1N1) pdm09 virus infection.

BACKGROUND Influenza pneumonia often occurs as epidemics in the Asian countries and have significant impact on the health of world population. METHODS We studied the association of rain-wetting with occurrence of pneumonia during the outbreak of the influenza A (H1N1) pdm09 virus infection. All patients admitted with community-acquired pneumonia during the period 13th September to 10th October 2010 were recruited in the present study. The diagnosis of influenza was established by real-time polymerase chain reaction (RT-PCR). The demographic data and clinical profile of the patients were recorded with a special consideration to record of possible risk factors. RESULTS Of the 123 patients studied, 39 (32%) patients had tested positive for influenza A (H1N1) pdm09; 12 (10%) tested positive for influenza A and remaining 72 (58%) patients were negative for influenza virus. Pattern of illness was almost identical in H1N1-positive and-negative groups. History of rain-wetting was present in 48 patients (39%) preceding the onset of illness. Getting wet in the rain was significantly higher in patients with pneumonia than control subjects [odds ratio 2.53, 95% confidence intervals (CI) 1.301-4.91; p=0.009)]. The number of pneumonia patients was also higher on rainy days and the numbers started declining a week later. CONCLUSION More pneumonia patients are admitted during the periods of greater rainfall and rain-wetting may be an important risk factor for the occurrence of pneumonia.