Clinical Care Providers, HIV County Program

Johns Hopkins HIV Service County Program

Our team of HIV specialists is composed of physicians, nurse practitioners, physician assistants, nurses, and case managers who offer the most recent treatments and help you to manage your healthcare.

Clinical Care Providers and Staff

David Griffith, MD – Medical Director, Clinical Associate 

David Griffith, MD received his MD from the University of Maryland.  He completed a residency in combined internal medicine and pediatrics at the University of Rochester, followed by fellowships in Pediatric and Adult Infectious Diseases at Johns Hopkins University.  He is board certified by the American Board of Internal Medicine and American Board of Pediatrics.

John Gerwig, PA-C, AAHIVS – Program Manager, Physician Assistant

John M. Gerwig PA-C received his PA training at Towson State University/Essex Community College.  He has held Physician Assistant (PA) certification from the National Commission on Certification of Physician Assistants since 1996.  He joined the Johns Hopkins AIDS Service in 1997 and has been the County Program Manager since 1999.  In 2018, he received the Miller-Coulson Nurse Practitioner/Physician Assistant Clinical Excellence Award.  The award recognizes mid-level practitioners who provide excellent clinical care in a thoughtful and caring manner.

Iryne-Zziwa-Kabenge-MSN-CRNP – Nurse Practitioner

Iryne Nakato Zziwa-Kabenge, CRNP graduated from the University of Maryland, School of Nursing with a BSN in 1997 and in 2008 attained a Masters in Nursing from Johns Hopkins University, School of Nursing.  She joined Johns Hopkins University in 2008 doing work with sexual health at the Baltimore City Health Department from 2008-2012.  In 2012, she joined the Johns Hopkins AIDS Service County program and currently provides HIV specialized care to patients enrolled in the County program.  She is credentialed through the American Nurses Credentialing Center (ANCC) and with the American Academy of HIV Specialists.

Meredith Harris MSN, MPH, CRNP, FNP-C – Nurse Practitioner

Meredith Harris graduated from the University of Virginia with a MSN in 2008 and became a Nurse Practitioner in 2014 after graduating from the University of Maryland FNP program. In 2021, she joined the Johns Hopkins HIV Service County program. She previously worked in primary care at a FQHC in Baltimore City focusing on family practice, school-based health, and refugee resettlement. Prior to becoming a Nurse Practitioner she worked as the HIV DOT Nurse Case Manager at the Baltimore City Health Department. She is certified through the American Association of Nurse Practitioners (AANP) and is a Qualified Bilingual Staff speaker of Spanish at Johns Hopkins.

Sheri Mancini, RN – Senior Clinical Nurse

Sheri Mancini, R.N. joined the Johns Hopkins AIDS service in 1988 as a clinic nurse. In 2000 she expanded her role to include nurse educator for the Project LINK adherence program. She became a member of the Johns Hopkins County Program in 2013.

Jane Creswell, RN– Clinical Nurse

Jane Creswell, RN graduated from Harford Community College in 2005.  She started her career with Infectious Disease as an HIV/AIDS Case Manager at the Harford County Health Department.  She has been a part of the Johns Hopkins County Program since 2012.

Patricia (Trish) Tichnell, RN– Senior Clinical Nurse, Western Region Telemedicine Program Manager

Ms. Tichnell graduated from Allegany College in 1981. She has 23 years of public health nursing experience and 10 years in infectious disease work including HIV. She is the Nurse Case Manager for the viral hepatitis telemedicine program located at the Allegany County Health Department in Cumberland, Maryland. She provides comprehensive screening, linkage to care and treatment services to persons living with hepatitis C in the western Maryland region.

Michelle Pollard, MEd, BSN, LC-ADC, CCM – Clinical Case Manager 

Michelle Pollard, CCM joined Johns Hopkins AIDS Service in 2015 as a Clinical Case Manager.  She comes with over 25-years of extensive training / skills in nursing, human service, social work, mental health, substance abuse, and vocation.  Her passion lies in client advocacy, ensuring every client has a voice / choice in their health care, resources to meet their medical / psychosocial goals, and to reduce barriers that interfere with communal stability.  As a clinical case manager, she remains on a mission to end new HIV/AIDS diagnosis, stop transmission, and stop stigma through education, communication, and medical management.

Kereen (Candy) McCullough – Office Manager, Senior Clinical Program Coordinator 

Ms. McCullough received her Bachelor’s degree in Health Services Management from University of Maryland, University College.  She is currently pursuing a Master’s degree in Health Care Management.  Kereen joined the HIV/AIDS county program in 2003.  She has over 21 years of experience with infectious diseases office management.

Pay a Bill

Johns Hopkins has simplified our billing statement. You will receive one bill for your care at Johns Hopkins Medicine. Questions? Call Customer Service, 1-855-662-3017

Online Payment

By Phone: 1-855-662-3017

By Mail: Mail you check or money order payable to Johns Hopkins Medicine, along with the coupon at the bottom of your statement.

OPAT Clinic Locations

Johns Hopkins Bayview Medical Center, Infectious Diseases Clinic
BMO – Blue Canopy, 01 Level
4940 Eastern Avenue Baltimore, MD 21224


Rockland Physician Practice at Greenspring Station
Johns Hopkins Falls Concourse
10751 Falls Road, Suite 412
Lutherville, MD  21093


John G. Bartlett Specialty Practice
The Park Building, Ground Floor
1717 E. Monument Street
Baltimore, MD  21205


Charitable Giving

The Michael Del Bianco Fund provides direct funding for HIV patient care needs not supported by other means, such as medications, housing, or other expenses.

Michael Del Bianco Fund

John Bartlett Specialty Practice Fund supports clinical activities for the entire ID practice, including patient and staff activities.

John Bartlett Specialty Practice Fund

Dr. John Bartlett HIV/AIDS Fund supports young trainees and junior faculty in the division, helping them transition to their independent careers.

Dr. John Bartlett HIV/AIDS Fund