Effect of Farming Environment on Atopic Diseases in Mongolia

RATIONALE: Viral infections and allergic inflammation are both associated with wheezing during childhood.In this study, the prevalence of viral pathogens and total IgE levels were evaluated among infants and children hospitalized for wheezing.METHODS: 133 wheezing children (ages 2 mos-18 yrs) and 133 age and gender matched controls were enrolled in a 12 month study.Nasal secretions were tested for RSV, influenza, paraiuflueuza, adenovirus, rhinovirus, coronavirus, and enterovirus by culture, RT-PCR (PCR for adenovirus), and antigen tests for RSV and influenza.Total IgE was measured in sera. RESULTS:The prevalence of viral pathogens among wheezing children by age was 84% (age <3 years, n = 79); 68% (ages 3-9 yrs, n = 34); and 50% (ages 10-18 yrs, n = 20).Among wheezing children <3 years, RSV and influenza were common during the mid-winter months.Only rhinovirus was significantly associated with wheezing from age 3 on (46% in wheezers; 1.8% in controls, p<0.001).Median total IgE levels for wheezing patients in the 3 age groups were 10.5,389, and 3461U/ml compared to 5.5, 48, and 31 IU/ml in controls (p<0.01;wheezers vs. controls in the 2 older age groups).CONCLUSIONS: Viral pathogens were common and total IgE levels low among children less than 3 years old.From age 3 on, only rhinovirus was significantly associated with wheezing and the prevalence of viral pathogens decreased with age.The atopic status of wheezing children from age 3 years on, however, was striking and did not decline with age.