diff --git a/tractor/_actor.py b/tractor/_actor.py
index 8ed3e4a..048d7b4 100644
--- a/tractor/_actor.py
+++ b/tractor/_actor.py
@@ -185,6 +185,9 @@ class Actor:
     _parent_main_data: Dict[str, str]
     _parent_chan_cs: Optional[trio.CancelScope] = None
 
+    # if started on ``asycio`` running ``trio`` in guest mode
+    _infected_aio: bool = False
+
     def __init__(
         self,
         name: str,
@@ -1000,6 +1003,8 @@ class Actor:
         log.info(f"Handshake with actor {uid}@{chan.raddr} complete")
         return uid
 
+    def is_infected_aio(self) -> bool:
+        return self._infected_aio
 
 class Arbiter(Actor):
     """A special actor who knows all the other actors and always has