diff --git a/cassandra/io/libevreactor.py b/cassandra/io/libevreactor.py
index 275f79c374..76a53b9bdd 100644
--- a/cassandra/io/libevreactor.py
+++ b/cassandra/io/libevreactor.py
@@ -225,7 +225,7 @@ def _loop_will_run(self, prepare):
 
 
 _global_loop = None
-atexit.register(partial(_cleanup, _global_loop))
+atexit.register(lambda: _cleanup(_global_loop))
 
 
 class LibevConnection(Connection):
diff --git a/cassandra/io/libevwrapper.c b/cassandra/io/libevwrapper.c
index 85ed551951..84d3d16bb2 100644
--- a/cassandra/io/libevwrapper.c
+++ b/cassandra/io/libevwrapper.c
@@ -114,6 +114,10 @@ IO_dealloc(libevwrapper_IO *self) {
 };
 
 static void io_callback(struct ev_loop *loop, ev_io *watcher, int revents) {
+    if (!Py_IsInitialized()) {
+        return;
+    }
+
     libevwrapper_IO *self = watcher->data;
     PyObject *result;
     PyGILState_STATE gstate = PyGILState_Ensure();
@@ -348,6 +352,10 @@ Prepare_dealloc(libevwrapper_Prepare *self) {
 }
 
 static void prepare_callback(struct ev_loop *loop, ev_prepare *watcher, int revents) {
+    if (!Py_IsInitialized()) {
+        return;
+    }
+
     libevwrapper_Prepare *self = watcher->data;
     PyObject *result = NULL;
     PyGILState_STATE gstate;
@@ -466,6 +474,10 @@ Timer_dealloc(libevwrapper_Timer *self) {
 }
 
 static void timer_callback(struct ev_loop *loop, ev_timer *watcher, int revents) {
+    if (!Py_IsInitialized()) {
+        return;
+    }
+
     libevwrapper_Timer *self = watcher->data;
 
     PyObject *result = NULL;