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 (see picture). The ring form is the most common (left panels whereas tetrads are rare (right panels). This parasite 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

The 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 begun to spread north and has reached 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.

Graph showing the increased rates of babesiosisThe State of New York was the first to institute mandatory reporting for babesiosis in 1986. Other states followed (open circles). As the new millennium started, greater numbers of cases were reported each year to the local public health departments. Starting in 2005, the rise of babesiosis accelerated even faster. In January of 2011, babesiosis became a nationally notifiable disease; cases are reported to the CDC (black circles).


A Successful Environment for Babesiosis

The recent emergence of babesiosis has been attributed to a cascade of environmental changes. Owing to the lack of predators and the public outcry over hunting, deer herds have become larger. Because ticks feed on deer, tick populations have thrived. As winters have become milder, ticks have survived in greater numbers. Culling deer herds has been proposed, but this measure has been difficult to implement. Tick repellents are available, but their use has failed to prevent the rise of human babesiosis.

Individuals at Risk

Ticks can be found in tall grassy areasIn young and healthy individuals, infection with Babesia microti typically is undetected 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 and loss of appetite. Symptoms may also include headache, nausea and muscle pain. In most mild cases, symptoms resolve spontaneously or are successfully treated with a single course of oral antibiotics.

In older adults and in individuals with impaired immune defense, babesiosis can be severe despite standard antibiotic therapy. Severe babesiosis often requires hospitalization. Among hospitalized individuals, about half develop at least one complication, and a significant number may die.

Most cases of babesiosis develop following the bite of an infected tick, but cases acquired through blood transfusion are on the rise. Transfusion transmitted babesiosis occurs because some blood donors do not have symptoms and 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:

  • Identify mechanisms that contribute to severe babesiosis
  • Develop novel therapeutic agents that help prevent or reverse severe babesiosis

The thrust of the research takes advantage of two common lines of laboratory mice. In one line, the infection is stronger as the age at infection increases. In the other, the infection remains marginal, even in old age. This sharp contrast is the basis of his genetic approach to uncover factors that confer susceptibility to babesiosis. To date, Dr. Vannier has identified and pursues:

  • A novel gene of red blood cells that confers susceptibility to babesiosis at young age
  • A chromosomal region that confers susceptibility to babesiosis in old age

A second approach explores host mechanisms by which immunocompromised mice clear Babesia microti parasites. To date, Dr. Vannier has identified and pursues:

  • An unusual immune cell type that proliferates during Babesia microti infection
  • A set of Babesia microti proteins that are targeted by antibodies as the infection clears
A third approach relies on the analysis of DNA obtained from patients who experienced mild or severe babesiosis, and from individuals who were infected with Babesia microti but did not have symptoms. The goal is to identify genetic variations that are associated with disease susceptibility or disease severity.

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 the immune response against this parasite.

They also aim to identify host factors that render some individuals prone to develop severe babesiosis. Because age is a risk factor for babesiosis, they expect to identify some of the fundamental changes that occur during 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 Mahrokhian
Senior at Tufts University, Medford, MA

Sarah Levine
Junior at Tufts University, Medford, MA

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 will deliver 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