An avian flu outbreak that has killed birds across Massachusetts in recent weeks is suspected to have spread to birds in Boston and Brookline, according to officials.

Bird flu is now believed to be widespread in Massachusetts and is likely present even in places where there has not been a confirmed positive, state environmental and health officials said Wednesday.

Baseless allegations circulate amid anxieties.

Scientists say the temporary freeze on communications from federal officials creates a troubling blind spot for those tracking the virus.