Observations of airborne Cryptomeria japonica pollen in the summer

ABSTRACTBackground: Airborne Cryptomeria japonica pollen has been detected from July to September, after the main pollen dispersal season (during florescence), in Toyama and Niigata prefectures, Japan.Methods: To identify the source of the pollen, two possible pathways were investigated: (i) secondary pollen dispersal from the ground; and (ii) release from male flowers remaining on the tree crown in C. japonica forests.Results: Secondary pollen dispersal from the ground ceased just after the main pollen dispersal season ended. However, male flowers remained on the crown until the end of September and released significant amounts of pollen, which contained as much allergenic Cry j 1 as normal pollen dispersed during the spring. There is a significant positive correlation between airborne pollen counts in the spring (February-May) and summer (June-September).Conclusions: These results indicate that the main sources of airborne pollen grains during the summer are male flowers remaining on the tree crown after their florescence

Antiviral Susceptibilities of Distinct Lineages of Influenza C and D Viruses

The emergence and spread of antiviral-resistant influenza viruses are of great concern. To minimize the public health risk, it is important to monitor antiviral susceptibilities of influenza viruses. Analyses of the antiviral susceptibilities of influenza A and B viruses have been conducted globally; however, those of influenza C and D viruses are limited. Here, we determined the susceptibilities of influenza C viruses representing all six lineages (C/Taylor, C/Yamagata, C/Sao Paulo, C/Aichi, C/Kanagawa, and C/Mississippi) and influenza D viruses representing four lineages (D/OK, D/660, D/Yama2016, and D/Yama2019) to RNA polymerase inhibitors (baloxavir and favipiravir) by using a focus reduction assay. All viruses tested were susceptible to both drugs. We then performed a genetic analysis to check for amino acid substitutions associated with baloxavir and favipiravir resistance and found that none of the viruses tested possessed these substitutions. Use of the focus reduction assay with the genotypic assay has proven valuable for monitoring the antiviral susceptibilities of influenza C and D viruses as well as influenza A and B viruses. Antiviral susceptibility monitoring of all influenza virus types should continue in order to assess the public health risks posed by these viruses