Sensitisation to Blattella germanica among adults with asthma in Yaounde, Cameroon: a cross-sectional study

BACKGROUND German cockroach or Blattella germanica is commonly found in homes across the inter-tropical region. The contribution of sensitisation to Blattella germanica in people with asthma in sub-Saharan Africa has not received attention. The aim of this study was to assess the prevalence and investigate the predicting factors of sensitisation to Blattella germanica in patients with asthma in Yaounde, Cameroon. METHODS This was a cross-sectional study conducted between January 2012 and June 2013. All patients (aged 15 years and above) with asthma, receiving care at the Yaounde Jamot Hospital and the CEDIMER medical practice during the study period and who had received a prick skin testing for perennial aeroallergens were included in the study. RESULTS The final sample comprised 184 patients including 123 (66.8%) women. The median age (25th-75th percentiles) was 38 (24-54) years. Prick skin test for Blattella germanica was positive in 47 (25.5%) patients. Sensitisation to Blattella germanica was associated with a sensitisation to mite in 41 (87.2%) patients, a sensitisation to Alternaria in 18 (38.3%) patients, and a sensitisation to cat or dog dander in 7 (14.9%) patients. Independent predicting factors of a sensitisation to Blattella germanica were the sensitisation to Blomia tropicalis [adjusted odd ratio (95% confidence interval) 4.10 (1.67-10.04), p = 0.002] and sensitisation to Alternaria [3.67 (1.53-7.46), p = 0.003]. CONCLUSIONS Sensitisation to Blattella germanica is present in about a quarter of adult patients with asthma in Yaounde. Sensitisation to Alternaria and Blomia tropicalis appears to be a powerful predicting factor of sensitisation to Blattella germanica in this setting.