diff --git a/examples/contrib/epidemiology/sir.py b/examples/contrib/epidemiology/sir.py
index 196a856f0d..1569f1ba38 100644
--- a/examples/contrib/epidemiology/sir.py
+++ b/examples/contrib/epidemiology/sir.py
@@ -66,7 +66,8 @@ def hook_fn(kernel, *unused):
         if args.verbose:
             logging.info("potential = {:0.6g}".format(e))
 
-    mcmc = model.fit(warmup_steps=args.warmup_steps,
+    mcmc = model.fit(heuristic_num_particles=args.num_particles,
+                     warmup_steps=args.warmup_steps,
                      num_samples=args.num_samples,
                      max_tree_depth=args.max_tree_depth,
                      num_quant_bins=args.num_bins,
@@ -184,6 +185,7 @@ def main(args):
     parser.add_argument("--dct", type=float,
                         help="smoothing for discrete cosine reparameterizer")
     parser.add_argument("-n", "--num-samples", default=200, type=int)
+    parser.add_argument("-np", "--num-particles", default=1024, type=int)
     parser.add_argument("-w", "--warmup-steps", default=100, type=int)
     parser.add_argument("-t", "--max-tree-depth", default=5, type=int)
     parser.add_argument("-r", "--rng-seed", default=0, type=int)
diff --git a/pyro/contrib/epidemiology/compartmental.py b/pyro/contrib/epidemiology/compartmental.py
index 2d3f20d805..baddcbcbbb 100644
--- a/pyro/contrib/epidemiology/compartmental.py
+++ b/pyro/contrib/epidemiology/compartmental.py
@@ -245,6 +245,8 @@ def fit(self, **options):
             Defaults to 4.
         :param float dct: If provided, use a discrete cosine reparameterizer
             with this value as smoothness.
+        :param int heuristic_num_particles: Passed to :meth:`heuristic` as
+            ``num_particles``. Defaults to 1024.
         :returns: An MCMC object for diagnostics, e.g. ``MCMC.summary()``.
         :rtype: ~pyro.infer.mcmc.api.MCMC
         """
@@ -254,7 +256,9 @@ def fit(self, **options):
 
         # Heuristically initialze to feasible latents.
         logger.info("Heuristically initializing...")
-        init_values = self.heuristic()
+        heuristic_options = {k.replace("heuristic_", ""): options.pop(k)
+                             for k in list(options) if k.startswith("heuristic_")}
+        init_values = self.heuristic(**heuristic_options)
         assert isinstance(init_values, dict)
         assert "auxiliary" in init_values, \
             ".heuristic() did not define auxiliary value"
diff --git a/tests/test_examples.py b/tests/test_examples.py
index d209274fdc..8eb27b55af 100644
--- a/tests/test_examples.py
+++ b/tests/test_examples.py
@@ -33,13 +33,13 @@
     'contrib/autoname/mixture.py --num-epochs=1',
     'contrib/autoname/tree_data.py --num-epochs=1',
     'contrib/cevae/synthetic.py --num-epochs=1',
-    'contrib/epidemiology/sir.py -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2',
-    'contrib/epidemiology/sir.py -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -e=2',
-    'contrib/epidemiology/sir.py -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -k=1',
-    'contrib/epidemiology/sir.py -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -e=2 -k=1',
-    'contrib/epidemiology/sir.py -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 --dct=1',
-    'contrib/epidemiology/sir.py -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -nb=8',
-    'contrib/epidemiology/sir.py -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -nb=16 --dct=1',
+    'contrib/epidemiology/sir.py -np=128 -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2',
+    'contrib/epidemiology/sir.py -np=128 -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -e=2',
+    'contrib/epidemiology/sir.py -np=128 -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -k=1',
+    'contrib/epidemiology/sir.py -np=128 -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -e=2 -k=1',
+    'contrib/epidemiology/sir.py -np=128 -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 --dct=1',
+    'contrib/epidemiology/sir.py -np=128 -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -nb=8',
+    'contrib/epidemiology/sir.py -np=128 -t=2 -w=2 -n=4 -d=20 -p=1000 -f 2 -nb=16 --dct=1',
     'contrib/forecast/bart.py --num-steps=2 --stride=99999',
     'contrib/gp/sv-dkl.py --epochs=1 --num-inducing=4 --batch-size=1000',
     'contrib/gp/sv-dkl.py --binary --epochs=1 --num-inducing=4 --batch-size=1000',