diff --git a/orca/topology/alerts/elastalert/extractor.py b/orca/topology/alerts/elastalert/extractor.py
index 11d87c7..728aa7b 100644
--- a/orca/topology/alerts/elastalert/extractor.py
+++ b/orca/topology/alerts/elastalert/extractor.py
@@ -14,6 +14,7 @@
 
 from orca.common import str_utils
 from orca.topology.alerts import extractor
+from orca.topology.alerts import properties as alert_props
 
 
 class Extractor(extractor.Extractor):
@@ -36,6 +37,10 @@ class AlertExtractor(Extractor):
     def _extract_name(self, entity):
         return entity['name']
 
+    def _extract_status(self, entity):
+        # TODO: Differentiate UP/DOWN status
+        return alert_props.AlertStatus.UP
+
     def _extract_source_labels(self, entity):
         labels = entity['kubernetes'].copy()
         labels.pop('labels', None)
diff --git a/orca/topology/alerts/extractor.py b/orca/topology/alerts/extractor.py
index 19179d7..53179da 100644
--- a/orca/topology/alerts/extractor.py
+++ b/orca/topology/alerts/extractor.py
@@ -18,6 +18,7 @@
 from orca.common import config, file_utils, logger
 from orca.graph import graph
 from orca.topology import extractor
+from orca.topology.alerts import properties as alert_props
 
 CONFIG = config.CONFIG
 LOG = logger.get_logger(__name__)
@@ -37,18 +38,25 @@ def kind(self):
 
     def extract(self, entity):
         name = self._extract_name(entity)
+        status = self._extract_status(entity)
         labels = self._extract_source_labels(entity)
         source_mapping = self._source_mapper.map(name, labels)
         node_id = self._build_id(name, source_mapping)
         properties = self._extract_properties(entity)
         properties['name'] = name
+        properties['status'] = status
         properties['source_mapping'] = source_mapping
-        return graph.Node(node_id, properties, self.origin, self.kind)
+        node = graph.Node(node_id, properties, self.origin, self.kind)
+        return Alert(node)
 
     @abc.abstractmethod
     def _extract_name(self, entity):
         """Extract name from given entity object."""
 
+    @abc.abstractmethod
+    def _extract_status(self, entity):
+        """Extract alert status from given entity object."""
+
     @abc.abstractmethod
     def _extract_source_labels(self, entity):
         """Extract labels from given entity object."""
@@ -127,3 +135,18 @@ def _validate_value(self, value, mapping):
         if value in mapping['blacklist_values']:
             return False
         return True
+
+
+class Alert(object):
+
+    """Decorator for alert nodes."""
+
+    def __init__(self, node):
+        self._node = node
+
+    def __getattr__(self, name):
+        return getattr(self._node, name)
+
+    @property
+    def is_up(self):
+        return self._node.properties.status == alert_props.AlertStatus.UP
diff --git a/orca/topology/alerts/falco/extractor.py b/orca/topology/alerts/falco/extractor.py
index 3c55512..fc83716 100644
--- a/orca/topology/alerts/falco/extractor.py
+++ b/orca/topology/alerts/falco/extractor.py
@@ -14,6 +14,7 @@
 
 from orca.common import str_utils
 from orca.topology.alerts import extractor
+from orca.topology.alerts import properties as alert_props
 
 
 class Extractor(extractor.Extractor):
@@ -36,6 +37,10 @@ class AlertExtractor(Extractor):
     def _extract_name(self, entity):
         return entity['rule']
 
+    def _extract_status(self, entity):
+        # TODO: Differentiate UP/DOWN status
+        return alert_props.AlertStatus.UP
+
     def _extract_source_labels(self, entity):
         return entity['output_fields']
 
diff --git a/orca/topology/alerts/falco/ingestor.py b/orca/topology/alerts/falco/ingestor.py
index 6e3b61c..067c67a 100644
--- a/orca/topology/alerts/falco/ingestor.py
+++ b/orca/topology/alerts/falco/ingestor.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from orca.topology import ingestor
+from orca.topology.alerts import ingestor
 from orca.topology.alerts.falco import extractor
 
 
diff --git a/orca/topology/alerts/ingestor.py b/orca/topology/alerts/ingestor.py
new file mode 100644
index 0000000..a01f745
--- /dev/null
+++ b/orca/topology/alerts/ingestor.py
@@ -0,0 +1,29 @@
+# Copyright 2020 OpenRCA Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from orca.topology import ingestor
+
+
+class Ingestor(ingestor.Ingestor):
+
+    """Base class for alert ingestors."""
+
+    def _ingest_event(self, event):
+        alert = self._extractor.extract(event)
+        if self._graph.get_node(alert.id):
+            self._graph.update_node(alert)
+            if not alert.is_up:
+                self._graph.delete_node(alert.id)
+        elif alert.is_up:
+            self._graph.add_node(alert)
diff --git a/orca/topology/alerts/prometheus/extractor.py b/orca/topology/alerts/prometheus/extractor.py
index 927184d..9aa038f 100644
--- a/orca/topology/alerts/prometheus/extractor.py
+++ b/orca/topology/alerts/prometheus/extractor.py
@@ -14,6 +14,7 @@
 
 from orca.common import str_utils
 from orca.topology.alerts import extractor
+from orca.topology.alerts import properties as alert_props
 
 
 class Extractor(extractor.Extractor):
@@ -36,19 +37,20 @@ class AlertExtractor(Extractor):
     def _extract_name(self, entity):
         return entity['labels']['alertname']
 
+    def _extract_status(self, entity):
+        if entity['state'] == 'firing':
+            return alert_props.AlertStatus.UP
+        return alert_props.AlertStatus.DOWN
+
     def _extract_source_labels(self, entity):
         return entity['labels']
 
     def _extract_properties(self, entity):
         properties = {}
-        properties['status'] = self._extract_status(entity)
         properties['severity'] = self._extract_severity(entity)
         properties['message'] = self._extract_message(entity)
         return properties
 
-    def _extract_status(self, entity):
-        return entity['state']
-
     def _extract_severity(self, entity):
         return entity['labels']['severity']
 
diff --git a/orca/topology/alerts/prometheus/ingestor.py b/orca/topology/alerts/prometheus/ingestor.py
index e4a55a1..2cc9dcd 100644
--- a/orca/topology/alerts/prometheus/ingestor.py
+++ b/orca/topology/alerts/prometheus/ingestor.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from orca.topology import ingestor
+from orca.topology.alerts import ingestor
 from orca.topology.alerts.prometheus import extractor
 
 
diff --git a/orca/topology/alerts/properties.py b/orca/topology/alerts/properties.py
new file mode 100644
index 0000000..1c3cfff
--- /dev/null
+++ b/orca/topology/alerts/properties.py
@@ -0,0 +1,18 @@
+# Copyright 2020 OpenRCA Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+class AlertStatus:
+
+    UP = 'up'
+    DOWN = 'down'
diff --git a/orca/topology/alerts/zabbix/extractor.py b/orca/topology/alerts/zabbix/extractor.py
index 0ef6f0f..4811398 100644
--- a/orca/topology/alerts/zabbix/extractor.py
+++ b/orca/topology/alerts/zabbix/extractor.py
@@ -14,6 +14,7 @@
 
 from orca.common import str_utils
 from orca.topology.alerts import extractor
+from orca.topology.alerts import properties as alert_props
 
 
 class Extractor(extractor.Extractor):
@@ -36,17 +37,18 @@ class AlertExtractor(Extractor):
     def _extract_name(self, entity):
         return entity['trigger'][0]
 
+    def _extract_status(self, entity):
+        if entity['trigger'][2] == '1':
+            return alert_props.AlertStatus.UP
+        return alert_props.AlertStatus.DOWN
+
     def _extract_source_labels(self, entity):
         return {'node': entity['host']}
 
     def _extract_properties(self, entity):
         properties = {}
-        properties['status'] = self._extract_status(entity)
         properties['severity'] = self._extract_severity(entity)
         return properties
 
-    def _extract_status(self, entity):
-        return 'active' if entity['trigger'][2] == '1' else 'inactive'
-
     def _extract_severity(self, entity):
         return entity['trigger'][1]