Do birds, houseflies and other insects including cockroaches pose a danger of spreading the virus?

Hi @respect thats a great question! However this is still uncertain in the context of this new and ongoing pandemic. While researchers are fairly certain that the COVID-19 virus began as a zoonotic infection that likely started spread to humans from bats, it is not certain if it can spread to other animals and insects as mentioned. Ultimately, the best way to reduce your risk of catching the infection is through hand hygiene and wearing masks when exposed to others (or even animals) that are unwell.

The CDC echoes this uncertainty, and has also shared about a possible case of spread from humans to tigers/lions in a New York zoo here: https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/animals.html