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, RN; Perla Adames Castillo, RN; Amy Klion, M.D.; Paneez Khoury, M.D., MHSc; JeanAnne Ware, MPH, CRNP, Elise O’Connell, M.D.; Celeste Nelson, MS, CRNP Back Row (left to right): Gregory Constantine, M.D.; Thomas Nutman, M.D.; William Sears, MPH, M.D.; Lauren Wetzler, MHS, PA-C, Thomas Brown, RN; Ejiofor Ezekwe, M.D., Ph.D.
Elise M. O’Connell, M.D. (She/Her/Hers)
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
Dr. O’Connell received her medical degree from Loyola University of Chicago. She is a board-certified physician in Internal Medicine and Infectious Diseases and completed residency at Indiana University and fellowship at the National Institute for Allergy and Infectious Diseases (NIAID/NIH).

Jiana L. Blaha, MHS (She/Her/Hers)
NIH/NIAID Postbac IRTA
Education:
MHS., 2021, Johns Hopkins University
B.S., 2020, American University
Languages Spoken: Spanish
Thomas Brown, RN (He/Him/His)
Nurse Specialist, CCRP

Perla Adames Castillo, RN (She/Her/Hers)
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. (He/Him/His)
Assistant Research Physician
Education:
M.D., University of Texas Long School of Medicine
Internal Medicine, Baylor College of Medicine
Allergy Immunology, National Institute of Allergy and Infectious Disease, NIH
Languages Spoken: Spanish

Gustavo Cuevas
Clinical Research Coordinator
Languages Spoken: Spanish
Ejiofor Ezekwe, M.D., Ph.D. (He/Him/His)
Allergy and Immunology Clinical Fellow
Education:
Pediatrics Residency, University of North Carolina
Ph.D., University of North Carolina
Medical School, University of North Carolina
Janitizio Guzman, M.D.
Infectious Diseases Fellow
Education:
Internal Medicine/Pediatrics Residency, University of Oklahoma School of Community Medicine, Tulsa, OK
Doctor of Medicine, University of Texas School of Medicine at San Antonio, San Antonio, TX
Bachelor of Science, The Ohio State University, Columbus, OH
Languages Spoken: Spanish

Paneez Khoury, M.D., M.H.Sc., FAAAAI (She/Her/Hers)
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

Amy Klion, M.D.
Chief, Human Eosinophil Section
Education:
B.A., Princeton University
M.D., New York University School of Medicine
Dr. Klion earned her B.A. from Princeton University and her M.D. from New York University School of Medicine. After completing a residency in internal medicine at Johns Hopkins University, she was a postdoctoral fellow in the Laboratory of Parasitic Diseases from 1989 to 1991. She completed her fellowship in infectious diseases at the University of Iowa Hospitals and Clinics in Iowa City, Iowa, where she was appointed an assistant professor in the division of infectious diseases prior to returning to the Laboratory of Parasitic Diseases in 1997 as a staff clinician. She became a tenure-track clinical investigator in the Laboratory of Parasitic Diseases in 2009 and a senior clinical investigator in 2014.

Celeste Gerise Nelson M.S., C.R.N.P. (She/Her/Hers)
Advanced Practice Nurse (CRNP)
Celeste is a family nurse practitioner with the Laboratory of Allergic Diseases since 2008 working on multiple protocols for allergic disorders including urticaria, atopic dermatitis, capillary leak and genetic disorders of allergic inflammation.

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

William J. Sears, M.D., MHS (He/Him/His)
Infectious Disease Fellow
Education:
Med/Peds Residency, Indiana University
M.D., University of Louisville School of Medicine
MHS, Johns Hopkins School of Public Health
Languages Spoken: Spanish
I am a physician scientist interested in applying genomics and molecular biology to improve our understanding of parasitological phenomena and their clinical manifestations.
Adrienne Showler, M.D. (She/Her/Hers)
Attending Physician
Education:
Medical School, University of Ottawa
Residency, University of Toronto Faculty of Medicine
Fellowship, University of Toronto Hospital
Languages Spoken: French
Dr. Adrienne Showler is an infectious disease and clinical tropical medicine physician focused on diagnosis and treatment of neglected tropical diseases in travelers and foreign-born populations.

JeanAnne M. Ware, MPH, CRNP (She/Her/Hers)
Nurse Practitioner, CRNP, FNP-BC
Education:
BSN, Johns Hopkins University
MSN, University of California San Francisco Family Nurse Practitioner Program
MPH, 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 (She/Her/Hers)
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
Nina Lei Tang, BS (She/Her/Hers), Postbaccalaureate IRTA Fellow; Education: BA, Barnard College; Languages spoken (other than English): French
Nina studied the immunopathology of neurocysticercosis with a particular focus on the local immune environment of subarachnoid neurocysticercosis and the persistence of seropositivity following cure of active disease. After NIAID: M.D./Ph.D. program at Baylor College of Medicine
Aissatou Bah, BS. After NIAID: M.D. program at University of Minnesota
Madelyn Corda, BS. After NIAID: Campbell University School of Osteopathic Medicine
Lauren Thumm, RN. After NIAID: Merck
Nicole Holland, RN. After NIAID: HRSA