Geographic Medicine and Infectious Diseases

Babesiosis Research Program

Babesiosis CellsWhat is Babesiosis?

Babesiosis is an infectious disease caused by parasites which invade and burst red blood cells open. In the United States, particularly along the northeastern seaboard, babesiosis is caused by Babesia microti. The ring form is the most common (left panels) whereas tetrads are rare (right panels). Babesia microti is carried by white-footed mice, and is transmitted from one mouse to another by the deer tick. Unfortunately, deer ticks feed on people, thereby transmitting the parasite. Unlike Lyme disease, its fellow traveler, babesiosis can be life-threatening. The infection also can be acquired through transfusion of contaminated blood products.

The Rise of Babesiosis

A graph that shows the reported case numbers from 1986 to 2018The first case of babesiosis occurred in 1969 in a patient who had vacationed on Nantucket. Nowadays, babesiosis is prevalent on the islands off the coast of southern New England, from Cape Cod to Connecticut and from the Lower Hudson Valley to Maryland. The disease has spread north, reaching all of New England. Cases also are reported from the upper Midwest, particularly Wisconsin and Minnesota. Once a rare and obscure disease, babesiosis has become a serious public health issue.

The State of New York was the first to institute mandatory reporting in 1986. Other states soon followed (open circles). As the new millennium started, greater numbers of cases were reported to the local public health departments. Starting in 2005, the rise of babesiosis accelerated even faster. Since 2011, babesiosis is a nationally notifiable disease; cases are reported to CDC (black circles). 

Individuals at Risk

Ticks can be found in tall grassy areasIn young and healthy individuals, infection with Babesia microti typically is silent or causes a mild illness. Fever is the main symptom, preceded by a gradual onset of fatigue and malaise. Fever often is accompanied by chills, sweats, headache, muscle pain and loss of appetite. In mild cases, symptoms resolve spontaneously or are successfully treated with a single course of oral antibiotics.

In adults above 50 years of age and in individuals with impaired immune defense, babesiosis can become so severe that hospital admission is required. Diarrhea, vomiting and nausea are good predictors of severe illness. Among hospitalized individuals, one half develops at least one complication, such as renal failure, pulmonary edema, disseminated intravascular coagulation or splenic rupture. Despite antimicrobial therapy, up to 3% of patients admitted for severe babesiosis eventually die. The mortality rate has reached ~20% among patients who are immunocompromised.

Most cases of babesiosis develop 1 to 4 weeks following the bite of an infected tick. Babesia microti can also be acquired via blood transfusion. If so, symptoms typically develop 3 to 7 weeks after the transfusion. In rare cases, the incubation period has lasted as long as 6 months. Transfusion transmitted babesiosis occurs because some blood donors are unaware that they are infected with Babesia microti.

Dr. Edouard Vannier, Assistant Professor at Tufts Medical Center, collaborates with leading scientists and expert clinicians in Boston and elsewhere in New England to understand and develop novel therapies for severe babesiosis.

The thrust of his research takes advantage of two lines of laboratory mice. In one line, the infection is stronger when the age at infection increases. In the other, the infection remains marginal, even in old age. To date, Dr. Vannier has identified and pursues:

  • A novel gene of red blood cells that renders young mice susceptible to babesiosis
  • A region in the genome that contributes to severe babesiosis in old age 

A second approach relies on the analysis of DNA obtained from patients who experienced mild or severe babesiosis. The goal is to identify genetic variants that are associated with disease susceptibility or disease severity. Practical outcomes of this work include:

  • The development of a test to identify people at risk of severe babesiosis
  • The identification of a novel host protein as therapeutic target in severe babesiosis

A third approach explores pathways by which immunocompromised mice clear an infection with Babesia microti parasites. To date, Dr. Vannier has identified or pursues:

  • An unusual immune cell type that help clear Babesia microti parasites
  • A set of Babesia microti proteins that are targeted by host antibodies as the infection resolves
  • The development of a babesiosis vaccine to protect people at risk of severe disease

Current therapies for babesiosis target Babesia microti itself (using antibiotics) or parasitized red blood cells (using exchange transfusion).

Dr. Vannier and his team are committed to enriching the therapeutic arsenal against babesiosis and seek to identify novel means (compounds/antibodies) to prevent the invasion of red blood cells by Babesia microti or strengthen of the host immune response against this parasite.

Because aging is a risk factor for severe babesiosis, Dr. Vannier’s research is poised to identify some of the fundamental changes that underlie the aging process and render the elderly susceptible to infection.

Edouard Vannier, PharmD, PhD
Assistant Professor, Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center and Tufts University School of Medicine

Shant H. Mahrokhian
First-year Medical Student, Tufts University School of Medicine

Tine Vindenes, MD, MPH
Attending Physician, Assistant Professor of Medicine, Tufts University School of Medicine

Michael R. Jordan, MD, MPH
Attending Physician, Assistant Professor of Medicine, Tufts University School of Medicine

June 26, 2020 – Dr. Vannier presents his work at the Virtual Research Symposium organized by the Global Lyme Alliance. The title of his talk is “Exploring the Antibody Response to Babesia microti”.

April 20, 2020 – Dr. Vannier is an author on the study that demonstrates the efficacy of clofazimine against severe Babesia microti infection in highly immunocompromised mice. This study is published in The Journal of Infectious Diseases (10.1093/infdis/jiaa195).

March 15, 2019 – Dr. Vannier presents his work at the Annual Research Symposium organized by the Global Lyme Alliance in Tarrytown, NY. His presentation is entitled “The Role of Antibodies in Babesia microti Infection”.

September 11-14, 2018 – Dr. Vannier contributes two presentations at the 15th International Conference on Lyme Borreliosis and other Tick-borne Diseases held in Atlanta, GA. The first poster is entitled “Identification of Babesia microti antigens for the development of therapeutic antibodies”; the second poster is entitled “A reservoir-targeted vaccine against Borrelia burgdorferi reduces the prevalence of Babesia microti infected ticks”.

August 22, 2018 – Dr. Vannier delivers a keynote lecture entitled “An Appraisal of Human Babesiosis in the USA” at the 14th International Congress of Parasitology in Daegu, South Korea.

April 12, 2018 – Dr. Vannier gives a presentation entitled “The Humoral Response in Babesiosis – Simply a Biomarker?” at the 1st Human Babesiosis Meeting that convened at Yale University in New Haven, CT.

February 3, 2017 – Dr. Vannier participates in the presentation and discussion of a human case of babesiosis during Grand Rounds at Tufts Medical Center in Boston, MA.

November 15, 2016 – Dr. Vannier gives a presentation on the “The Rationale for an Antibody-based Therapy in Severe Babesiosis” at the 65th Annual Meeting of the American Society of Tropical Medicine and Hygiene in Atlanta, GA.

May 14, 2016 – Drs. Gelfand and Vannier jointly provide an appraisal entitled “Babesiosis: Critical Issues” during the 2nd Conference on Lyme Disease and Tick-Borne Illnesses organized at the Massachusetts General Hospital in Boston, MA.

September 27, 2015 – Dr. Vannier gives a presentation entitled “Aging resets the genetic architecture of host resistance to babesiosis” at the 14th International Conference on Lyme Borreliosis and Other Tick-Borne Diseases in Vienna, Austria.

November 10, 2014 – Dr. Vannier contributes a talk entitled “Immune Basis for Resolution of Severe Babesiosis” during a monthly gathering of the Boston Area Parasitology Symposium (BAPS) organized at the T. Chen Harvard School of Public Health, Boston, MA.

June 4, 2014 – Dr. Vannier, in collaboration with Dr. John Leong, Chief of Molecular Biology and Microbiology at Tufts University School of Medicine and Dr. Arlin Rogers, Associate Professor at the Tufts Cummings School of Veterinary Medicine, is granted a Tufts Collaborates! Award for the project entitled “A Novel Genetic Determinant of Susceptibility to Colonic Inflammation”. The proposed research will use the Citrobacter rodentium mouse model to determine whether a novel determinant of susceptibility to babesiosis confers susceptibility to colonic inflammation.

April 23, 2014 – Dr. Vannier is granted funds by the National Research Center for Protozoan Diseases (NRCPD) and Obihiro University of Agriculture and Veterinary Medicine (OUAVM) for the research project entitled “Identification of Novel Therapeutics for Babesiosis”. This project will be carried out in collaboration with Pr. Ikuo Igarashi (NRCPD and OUAVM).

December 9, 2013 – Dr. Vannier gives a lecture entitled “Determinants of Host Resistance to Babesiosis, an Emerging Infectious Disease” at the National Research Center for Protozoan Diseases in Obihiro, Hokkaido, Japan.

August 19, 2013 – Dr. Vannier presents his research on the “Immune Basis for Resolution of Babesia microti Infection in Immunosuppressed Hosts” at the 13th International Conference of Lyme Borreliosis and Other Tick-Borne Diseases in Boston, MA.

August 15, 2013 – Dr. Vannier gives a presentation entitled “Cytokines in Host Resistance to Babesiosis, an Emerging Infectious Disease” at the Special Symposium organized by the Interleukin Foundation at the University of Colorado in Denver, CO.

Read the Press Release by the National Research Fund for Tick-Borne Diseases on February 15, 2013. Dr. Vannier receives one of their four awards in support of his groundbreaking research on the genetic variations that predispose people to severe babesiosis.

Read the New York Times article entitled Another Tick-Borne Disease to Guard Against published on July 30, 2012. This article highlights the importance of babesiosis research and Dr. Vannier's role in shaping how this research is being conducted.

Dr. Vannier’s research bears the promise of great scientific advances, but requires long-term investment. Your contribution can help maintain a strong research program in babesiosis.

Few years ago, Dr. Vannier was fortunate to meet Dr. Tris Dammin and his wife Beverly. They have been strong advocates of his research on babesiosis, keeping alive the family interest in tick-borne diseases – the deer tick was named Ixodes dammini to honor Tris’ father, the late Pr. Gustave Dammin.  With their support, the "Babesiosis Research Fund" at Tufts Medical Center was created.

This 501(c)(3) fund exclusively supports Dr. Vannier’s research. Your gift will be fully tax deductible as allowed by law. To donate, please visit our Tufts Medical Center Trust website, click on “Give Now” (orange box at bottom in right column), type the amount of donation, select "Other" from the Gift Designation dropdown menu, and type "Babesiosis Research Fund" in the field beneath.

You can also donate by calling 617-636-7656 or mailing a check to Tufts Medical Center Trust, 800 Washington Street #231, Boston, MA 02111. Please make your check payable to Tufts Medical Center Trust, and indicate that you are donating to the Babesiosis Research Fund.

Thank you for your interest and generosity.

Phone: 617-636-8526

E-mail: evannier@tuftsmedicalcenter.org