The Clinical Parasitology Unit is an interdisciplinary group of clinically trained LPD staff members who oversee the clinical research portfolio and provide clinical care, consultations, and training in tropical medicine and parasitology. The overriding goals of this program are:
- To gain insight into the clinical syndromes associated with parasitic infections
- To understand and help define the pathogenesis underlying clinical disease
- To identify better ways of treating individual infections and to prevent secondary consequences of treatment
- To develop better diagnostic tools for the species-specific diagnosis of active parasitic infection
Although the Clinical Parasitology Unit has protocols to see patients with any parasitic infection, the overwhelming majority of patients have neurocysticercosis, filarial infections (lymphatic filariasis, onchocerciasis, loiasis, mansonellosis), strongyloidiasis, Chagas disease, hookworm infections, ascaraisis, giardiasis, echinococcosis, and leishmaniasis. We occasionally see patients with gnathostomiasis, African trypanosomiasis, and malaria, among others.
Clinical Parasitology Unit, June 2022: Front Row (left to right): Nicole Holland, R.N. (former member); Perla Adames Castillo, R.N.; Amy Klion, M.D.; Paneez Khoury, M.D., MHSc; JeanAnne Ware, M.P.H., C.R.N.P.; Elise O’Connell, M.D., Senior Investigator; Celeste Nelson, M.S., C.R.N.P. Back Row (left to right): Gregory Constantine, M.D.; Thomas Nutman, M.D.; William Sears, M.P.H., M.D. (former member); Lauren Wetzler, MHS, PA-C; Thomas Brown, R.N.; Ejiofor Ezekwe, M.D., Ph.D.
Elise M. O’Connell, M.D.
Chief, Clinical Parasitology Unit
Associate Research Physician
Specialty(s): Infectious Disease, Internal Medicine Provides direct clinical care to patients at NIH Clinical Center
Education:
M.D., Loyola University Chicago
Jessica Bass, D.O.
Infectious Disease Clinical Fellow
Education:
D.O., Kansas City University of Medicine and Biosciences
Residency, NCH Healthcare System Internal Medicine Residency
Chief Resident, NCH Healthcare System Internal Medicine Residency
Fellowship, NIH Infectious Disease Fellowship
Languages Spoken: Spanish
My research projects include identifying Helicobacter pylori (H. pylori) antibiotic resistance genes, diagnosis of H. pylori utilizing an entero-string test, and clinical outcomes of H. pylori resistance-guided treatment in patients who have failed prior therapies.
My clinical interests include tropical medicine and parasitology.
Thomas Brown, R.N.
Nurse Specialist, CCRP
Thomas is the study coordinator for the following protocols: Natron, Pilot Study of Mepolizumab in Episodic Angioedema with Eosinophilia, Collection of blood, body fluid and tissue specimens from healthy donors for use in in vitro research, An Open-Label, Proof-of-Concept Study to Evaluate the Safety and Efficacy of Dexpramipexole (KNS-760704) in Subjects with Hypereosinophilic Syndrome, A Phase 2...
Perla Adames Castillo, R.N.
Nurse Research Specialist
Languages Spoken: Spanish
Perla is study coordinator for the Cysticercosis, Leishmaniasis, and Chagas arm of the Parasite Screening protocols.
Gregory M. Constantine, M.D.
Assistant Research Physician, Human Eosinophil Section (HES), Laboratory of Parasitic Diseases (LPD)
Specialty(s): Allergy and Immunology, Internal Medicine Provides direct clinical care to patients at NIH Clinical Center
Education:
M.D., University of Texas Long School of Medicine, San Antonio, TX
Residency, Internal Medicine, Baylor College of Medicine, Houston, TX
Chief Residency, Internal Medicine, Baylor College of Medicine, Houston, TX
Fellowship, Allergy and Immunology, National Institute of Allergy and Infectious Disease, NIH, Bethesda, MD
Gregory Constantine, M.D., is an Assistant Research Physician Clinician at NIAID. He has been involved in translational research in eosinophilic disorders since joining the Human Eosinophil Section in 2020.
He received his M.D. from the University of Texas Long School of Medicine, followed by a residency in internal medicine at Baylor College of Medicine (BCM). He was then selected and served as...
Gustavo Cuevas
Clinical Research Coordinator
Languages Spoken: Spanish
Harris Richard Droghini, M.D.
Allergy and Immunology Fellow
Education:
BMus, Vanderbilt University
M.D., Medical University of South Carolina
I am interested in the modulation of the immune system and allergic responses by helminth infections, in particular, the human whipworm (Trichuris trichiura) in a Phase 1 clinical trial (NCT05706116). I am also working on developing a novel approach to characterize the human gut microbiome.
Sabrina Hammond, B.S.
Postbaccalaureate IRTA Fellow
Education:
B.S. University of California, Berkeley
Sabrina graduated from the University of California, Berkeley in 2025. She has been working with Dr. Elise O’Connell in the Clinical Parasitology Unit evaluating differential immune responses in patients with subarachnoid and parenchymal neurocysticercosis.
Paneez Khoury, M.D., M.H.Sc., FAAAAI
Senior Clinician; Director, Allergy & Immunology Fellowship Training Program, Laboratory of Allergic Diseases (LAD)
Head, Eosinophil Clinical Research Unit, Human Eosinophil Section, Laboratory of Parasitic Diseases (LPD)
Specialty(s): Allergy and Immunology, Internal Medicine Provides direct clinical care to patients at NIH Clinical Center
Education:
M.D., University of Illinois College of Medicine, Chicago, IL
M.H.Sc., Duke University, Durham, NC
Paneez Khoury, M.D. is Senior Clinician in NIAID. She has been involved in translational research in eosinophilic disorders since joining the Human Eosinophil Section in 2012. She is the head of the Eosinophil Clinical Research Unit in the Human Eosinophil Section where she leads clinical investigative trials and studies in a variety of eosinophilic disorders.
She received her M.D. from University...
Amy Klion, M.D.
Co-Deputy Chief, Laboratory of Parasitic Diseases
Chief, Human Eosinophil Section
Education:
B.A., Princeton University
M.D., New York University School of Medicine
Michelle M. Luera, M.S.N.
Registered Nurse
Education:
M.S.N., Nursing Informatics, Nova Southeastern University, Fort Lauderdale, FL
B.S., Nursing, Florida International University, Miami, FL
Michelle is a certified pediatric nurse with experience in hematology/oncology, bone marrow transplant, and clinical research. She is also a study coordinator on the LPD screen, and she has experience in Chagas disease and the Hypereosinophilia protocol.
Celeste Gerise Nelson M.S., C.R.N.P.
Advanced Practice Nurse (C.R.N.P.)
Thomas Nutman, M.D.
Lab Chief, Laboratory of Parasitic Diseases
Chief, Helminth Immunology Section
Provides direct clinical care to patients at NIH Clinical Center
Education:
A.B., Brown University, Providence, RI
M.D., University of Cincinnati College of Medicine, Cincinnati, OH
Dr. Nutman received his A.B. from Brown University and his M.D. from the University of Cincinnati College of Medicine. He did an internal medicine residency at New York University (Bellevue) and postdoctoral training in the Laboratory of Parasitic Diseases (LPD). He is board certified in internal medicine and allergy and immunology. He also holds a diploma/certificate in tropical medicine and...
Adrienne Showler, M.D.
Attending Physician
Education:
Medical School, University of Ottawa
Residency, University of Toronto Faculty of Medicine
Fellowship, University of Toronto Hospital
Languages Spoken: French
JeanAnne M. Ware, M.P.H., C.R.N.P.
Nurse Practitioner, C.R.N.P., FNP-BC
Education:
BSN, Johns Hopkins University
MSN, University of California San Francisco Family Nurse Practitioner Program
M.P.H., Johns Hopkins Bloomberg School of Public Health
Languages Spoken: Spanish
Clinician and Associate Investigator on clinical trials for parasitology including leishmaniasis, neurocysticercosis, filarial diseases and Chagas disease, and hypereosinophilic disorders.
Lauren Wetzler, MHS, PA-C
Physician Assistant
Education:
MHS, Physician Assistant, Drexel University
BS, Biology, University of Maryland, College Park
Lauren began her career in 2011, initially specializing in neurosurgery and trauma. She transitioned to clinical research at NIH in 2014, serving as an associate investigator on multiple natural history and investigational drug studies spanning a range of parasitic infections and hypereosinophilic syndromes.
Former Research Group Members
- Janitzio Guzman, M.D., former NIAID Med-Peds Infectious Diseases fellow. After NIAID: Faculty position at Baylor College of Medicine
- Emily Miltenberger, B.S. After NIAID: M.D. program at the University of Indiana
- Nina Lei Tang, B.S. After NIAID: M.D./Ph.D. program at Baylor College of Medicine
- Aissatou Bah, B.S. After NIAID: M.D. program at University of Minnesota
- Madelyn Corda, B.S. After NIAID: Campbell University School of Osteopathic Medicine
- Lauren Thumm, R.N. After NIAID: Merck
- Nicole Holland, R.N. After NIAID: HRSA
- Jiana L. Blaha, M.H.S.
- William J. Sears, M.D., M.H.S.