Global Support

marc-mitchell dtree

Marc Mitchell

MD, MS, Founder and President of D-tree International

Marc Mitchell is a pediatrician and management specialist who has worked in over 40 countries in Africa, Asia, and Latin America on the design and delivery of health care services. He is a Lecturer on International Health at Harvard University School of Public Health where his areas of expertise include health management, health systems design, program development and evaluation. He has done training and consulting for a wide variety of organizations including the US Government (USAID, CDC and NIH), the World Bank, the Asian Development Bank, The African Development Bank, the National Health Service in the UK, PricewaterhouseCoopers, the United Nations (UNFPA, WHO), and private foundations and organizations. His research interests focus on the use of electronic standard medical protocols to increase access to high quality health care for the world’s poor. Dr. Mitchell holds degrees from Harvard University (BA, 1970), Boston University (MD, 1974), and MIT’s Sloan School of Management (MS, 1985).


Erica Layer

Chief Program Officer

Erica joined the D-tree team in Dar es Salaam in April 2014 and is now Chief Program Officer. She brings over eight years of international health and project management experience to D-tree. Erica holds a MSPH in international health from Johns Hopkins University, a BA in chemistry from the College of Saint Benedict and a Master’s certificate in project management from Villanova University. Prior to joining D-tree, Erica served as a Peace Corps Volunteer in South Africa where she worked in collaboration with rural communities on HIV prevention and community development projects. She later worked with the International AIDS Society in Geneva to manage the scientific program for the XVIII International AIDS Conference. Immediately prior to working with D-tree, Erica worked as a Senior Research Program Coordinator for Johns Hopkins University where she managed multiple HIV prevention research projects in Tanzania.

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Alison Clark

MS, Chief Operating Officer

Alison is D-tree’s Chief Operating Officer, with over ten years of nonprofit experience. She has worked in a variety of capacities including finance and accounting, marketing, grant writing and the facilitation and training of corporate and nonprofit professional groups in leadership and team building programs. She holds a Master’s of Science in Management from the SIT Graduate Institute, through the Program of Intercultural Service, Leadership and Management. Prior to joining the D-tree team, Alison was the Accounting Manager at an Outward Bound school in Boston. She is an avid traveler and passionate about improving health care in underserved communities.

Sarah Klem

Sarah Klem

Program Manager

Sarah Klem is a Program Manager for D-tree International based in Washington, D.C. With D-tree, she will be the lead for our program in Ethiopia as well as be the technical manager for D-tree’s international program portfolio. She has five years experience as a project manager designing and implementing healthcare software. Before joining D-tree, Sarah was an implementer for the Inpatient Physician and Infection Control applications for Epic, the leading American electronic medical records developer. She worked on hospital implementations for the University of Maryland Medical System, Cambridge University Hospitals (UK), the Denmark national health system, and Sint Antonius Ziekenhuis (the Netherlands). She received a BA in International Relations from the College of William and Mary.


Rebecca Litner

Program Manager

Rebecca is a Program Manager for D-tree International based in Washington, DC where she focuses on strategy and project management. She brings over 6 years of experience in program management and implementation for healthcare organizations, and is passionate about the impact that IT has on health system improvement. Prior to joining D-tree, Rebecca was a Senior Healthcare Consultant with Cognizant Technology Solutions where she managed digital health transformation projects for integrated health systems, product vendors and government entities. She has also supported NGOs on care coordination, patient engagement and health insurance strategies. Rebecca received her MPH in Health Policy and Management as well as BA in International Relations and Economics from Boston University.

Joseph Sweeney (2)

Joseph Sweeney


Joseph Sweeney graduated with a Bachelors in Administration with a concentration in Finance from the University of Massachusetts Lowell. Prior to joining D-tree, Joseph worked for two years as a Staff Accountant for Non Profit Capital Management, a consulting firm that specializes in nonprofit accounting and financial management. In his free time, Joseph enjoys reading, screen writing, and playing music.

Malawi Country Team


Chris Kulanga

BSc, Acting Malawi Country Director

Chris Kulanga currently serves as Acting Country Director for D-Tree in Malawi. Before joining D-tree, Chris was with Nkhoma Hospital as the IT Manager, coordinating and managing ICT systems in the hospital and surrounding rural health centers as well as community health workers. He holds a Bachelor of Science degree from Chancellor College of the University of Malawi. He has passion for health informatics and is currently finishing a Master of Science in Informatics degree with the University of Malawi.


Blessings Malizani

Finance and Administrative Officer

Blessings joined D-tree International in October 2015. Blessings is goal oriented with five years’ experience in financial reporting, controlling, planning & analysis, and interpersonal & team working skills. Blessings holds a Diploma in Accounting and is studying towards ACCA qualification. Prior to joining D-tree, she worked for JTI Leaf Malawi Ltd as a Financial Planning & Analysis Associate and also as Assistant Financial Consultant at Unique Financial Consultants.


Monica Meleke

BSc, Field Implementer

Monica holds a Bachelor of Science in Nursing and University Certificate in Midwifery from the University of Malawi. She also has a Diploma in Information Systems Analysis and Design from Digital Systems Limited. Prior to joining D-tree, she worked as a nurse midwife at Mulanje District Hospital.


Gerald Chilindira

Driver and Project Assistant

Gerald joined D-tree International in October 2015. He holds a Diploma in International Computer Studies and a certificate in procurement and supply chain management. Gerald is passionate about health & technology and prior to working with D-tree, he used to work at Lovell Park Consultants.


Chikumbutso Simukonda

Project Coordinator

Chikumbutso works as a Project Coordinator. She is a professionally trained (PMP) as a project manager and has seven years of experience in project management. She has a Bachelor’s degree in Information Systems from University of Venda in Limpopo, South Africa and she is a Microsoft Certified Professional. Prior to joining D-tree, Chikumbutso was a Program Manager at the British Council in Lilongwe. In her free time, she enjoys spending time with her family, reading and gardening.


Amanda Nazombe

Field Implementer

Amanda works as a Field Implementer, and joined D-tree as an intern in May 2016. She has a Bachelor of Arts in Humanities from University of Malawi, Chancellor College. Prior to joining D-tree Amanda worked in customer service and as a translator. In her free time, she likes to read and listen to books.

Tanzania Country Team


Gloria Kahamba

Project Manager

Gloria joined D-tree in October 2015, after finishing her studies at the University of California, Berkeley. She graduated with an MPH in Infectious Diseases and Vaccinology and a certificate in Global Health and also holds a BA in Human Ecology from the College of the Atlantic. As part of her training, Gloria interned with UCSF’s Global Health Group and traveled to Northeastern Namibia to assist with data collection and analysis, in an effort to enhance malaria surveillance and accelerate elimination in the region. She has also interned with the Department of Preventive Services at MOHSW in Tanzania. At D-tree, Gloria aims to work with the team to promote awareness and the use of innovative, evidence-based approaches to better population health and eventually, bring about policy change in Tanzania’s health delivery system.

Rachel Hofmann photo

Rachel Lieber Hofmann

Program Manager

Rachel has over six years of international health systems strengthening, program management, and business development experience. Before joining D-tree, Rachel provided technical and program management support to Management Sciences for Health’s accredited drug seller portfolio to improve access to quality medicines and pharmaceutical services through private sector pharmacies and drug shops. Rachel has also held technical positions with Jhpiego in Ethiopia and the World Health Organization in Geneva. She received an MSPH in international health systems from Johns Hopkins University and a BA in community health and political science from Tufts University. Rachel enjoys running, hiking, reading, and traveling.


Melania Nkaka

BSW, Field Coordinator

Melania works as a Field Coordinator assisting community and facility-level health workers to utilize mobile technology to provide maternal and HIV care in clinical settings with the goal to improve quality of care at the facility level. She holds a Bachelors degree of Social Work from the Institute of Social Work, a Diploma of Social Studies from the College of Mwalimu Nyerere Memorial Academy, and is a registered nurse and certified midwife. Previously, Melania worked as a nurse at Bugando Medical Center in Mwanza, as an HIV Project Health Research Officer at AMREF, and as a Research Assistant for a schistosomiasis project at NIMR in Mwanza region. In her free time, she enjoys spending time with her family and friends, reading, listening to music, and watching movieses.


Mariam Mapande

Field Implementer

Mariam works as a field implementer with D-tree in Dar es Salaam. She specializes in training community health workers on the use of mobile health tools and in ensuring ongoing programmatic success.  She holds an Certificate in Information Communication Technology from the University Of Dar es Salaam Computing Center, Tanzania. Before joining D-tree, Mariam worked as Data entry clerk at Pathfinder International in Tanzania.


Neema Kafwimi

Program Assistant

Neema Kafwimi, a data enthusiast joins us as a Program Assistant. She holds a Bachelor of Arts in Mathematics from Bates College. She has previously worked with professors from whom she gained research, programming, and data analysis skills. She has also had an opportunity to intern with different organizations, where she proposed the design of data collection and visualization systems. She brings to us her analytical background, design skills, and curiosity in understanding further how technology can be leveraged to solve world problems. Neema enjoys travelling, reading, writing and trying out new coffee shops.


Jalia Tibaijuka

Field Nurse Officer

Jalia holds a Diploma in Nursing and the Advanced Diploma in Nursing Ophthalmology from Kilimanjaro Christian Medical Center. She also received training in HIV/AIDS care in the community from South Chelsea College in London UK. Previous to joining D-tree, Jalia worked for years as a Nurse at Muhimbili National Hospital. Her interest is to assist D-tree and work as part of a team to improve health care in the Community, with a particular focus on severe acute malnutrition diagnosis and treatment programs for children on Zanzibar.


Salum Masuod Mbaruok

Field Implementer

Salum Holds B.A in Sociology from The University of Dar es Salaam specializing in Health and Population studies. He joined D-tree International in January 2017. Prior to join D-tree he worked as a Project Officer and a counselor in a local NGO known as JUKAMKUM dealing with HIV/AIDS, drug abuse and teenage pregnancy. He also worked as a tutor at the Time School of Journalism where he taught Gender and HIV/AIDS. He likes teaching, swimming and reading in his free time.


Stella Marealle

Administrative Assistant

Stella Marealle holds a degree in Business administration from Mzumbe University. She joined the D-tree team in December 2015 and brings experience in project management and administration.  Prior to joining D-tree, Stella worked with HYOSUNG CORPORATION on a project with TANESCO as an administrator and assistant accountant.  She was responsible for all administration, accounts, secretarial, human resources and logistics matters.  One of her biggest strengths is her ability to multi-task and carry out the diverse range of responsibilities in a timely and effective manner.  Stella is thrilled to join the D-tree team in our Zanzibar office.


Samira Said

Field Coordinator, Pemba

Samira Said works as a Field Coordinator in Pemba coordinating activities for the Safer Delivery project and collaborating with community health workers, health facilities and others involved in the project.  Prior to joining D-tree, Samira worked as a Social Worker and Program Officer for the Family Strengthening program with SOS Children’s Villages, and as a Monitoring and Evaluation Officer with STS International. She has a degree in Economics and Sociology from the University of Dodoma. In her free time, she enjoys watching movies, reading books, hiking and exercising.