Oral infection of Aedes aegypti with yellow fever virus: geographic variation and genetic consideration

Twenty-eight populations representing a worldwide distribution of Aedes aegypti were tested for their ability to become orally infected with yellow fever virus (YFV). Populations had been analyzed for genetic variations at 11 isozyme loci and assigned to one of 8 genetic geographic groups of Ae. aegypti. Infection rates suggest that populations showing isozyme genetic relatedness also demonstrate similarity to oral infection rates with YFV. The findings support the hypothesis that genetic variation exists for oral susceptibility to YFV in Ae. aegypti.(AU)

Changes in specific airway conductance in healthy volunteers following nasal and oral inhalation of SO2

Specific airway conductance (sGaw) was measured using a body plethysmograph in 49 healthy volunteers exposed by nose and mouth to sulphur dioxide (SO2) below and above the maximum allowable daily concentration of 5 p.p.m., for periods of up to 1 hour. SO2 caused a decrease in sGaw with both nose and mouth breathing at low concentrations. The decrease in sGaw was greater with mouth breathing. At high concentrations (above 5 p.p.m.) however, there was no significant difference between nose and mouth breathing. In subjects exposed to 5 p.p.m. SO2 for up to 1 hour, there was no further significant decrease in sGaw after 5 minutes. These results suggest that changes in sGaw following SO2 inhalation are related to stimulation of tracheobronchial receptors and that after a period acclimatization occurs (AU)