diff --git a/requirements.api.txt b/requirements.api.txt
index 01026935f..be24ee60f 100644
--- a/requirements.api.txt
+++ b/requirements.api.txt
@@ -2,19 +2,15 @@ delphi_utils==0.3.15
 epiweeks==2.1.2
 Flask==2.2.5
 Flask-Limiter==3.3.0
-jinja2==3.1.3
-more_itertools==8.4.0
 mysqlclient==2.1.1
+numpy==1.22.4
 orjson==3.4.7
 pandas==1.2.3
 python-dotenv==0.15.0
 pyyaml
 redis==3.5.3
-requests==2.31.0
-scipy==1.10.0
 sentry-sdk[flask]
 SQLAlchemy==1.4.40
 structlog==22.1.0
-tenacity==7.0.0
 typing-extensions
 werkzeug==2.3.8
diff --git a/requirements.dev.txt b/requirements.dev.txt
index c071f208d..97403013c 100644
--- a/requirements.dev.txt
+++ b/requirements.dev.txt
@@ -2,22 +2,18 @@ aiohttp==3.9.0
 black>=20.8b1
 bump2version==1.0.1
 covidcast==0.1.5
-delphi_utils==0.3.15
 docker==6.0.1
 dropbox==11.36.0
 freezegun==1.2.2
 invoke>=1.4.1
 lxml==4.9.1
-matplotlib==3.6.2
+more_itertools==8.4.0
 mypy>=0.790
 mysql-connector==2.2.9
-numpy==1.22.4
 pycountry==22.3.5
 pymysql==1.0.2
 pytest==7.2.0
-pytest-check==1.3.0
-sas7bdat==2.2.3
+requests==2.31.0
 selenium==4.7.2
-sqlalchemy-stubs>=0.3
 tenacity==7.0.0
 xlrd==2.0.1
diff --git a/src/acquisition/quidel/quidel.py b/src/acquisition/quidel/quidel.py
index 0540d5e7c..f2619be52 100644
--- a/src/acquisition/quidel/quidel.py
+++ b/src/acquisition/quidel/quidel.py
@@ -201,6 +201,7 @@ def prepare_csv(self):
                 print("End date not found in file name:" + f)
                 end_date = None
 
+            # NOTE: this pd.read_excel() method requires installation of the `xlrd` library:
             df_dict = pd.read_excel(join(self.excel_uptodate_path, f + ".xlsx"), sheet_name=None)
             for (_, df) in df_dict.items():
                 df = df.dropna(axis=0, how="all")