Babesiosis


Article Author:
Andrea Zimmer


Article Editor:
Kari Simonsen


Editors In Chief:
Amanda Oakley
Jules Lipoff
Shyam Verma


Managing Editors:
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Frank Smeeks
Kristina Soman-Faulkner
Benjamin Eovaldi
Radia Jamil
Sobhan Daneshfar
Saad Nazir
William Gossman
Pritesh Sheth
Hassam Zulfiqar
Navid Mahabadi
Steve Bhimji
John Shell
Matthew Varacallo
Ahmad Malik
Mark Pellegrini
James Hughes
Beata Beatty
Hajira Basit
Phillip Hynes


Updated:
12/16/2018 4:00:04 PM

Introduction

Babesiosis is an infectious disease caused by intraerythrocytic, tick-borne protozoa of the Babesia species.[1][2][3]

Etiology

Babesiosis is a parasitic infection caused by protozoa of the genus Babesia. Babesia species have been subdivided into four categories, known as clades. Babesia microti is the most prevalent and well-described species and is a classified as a Clade 1 organism. Babesiosis is typically acquired by bites from ticks carrying the protozoa. As the parasite infects erythrocytes (red blood cells), the infection can be acquired through blood transfusion and therefore can occur in persons who have not traveled to endemic areas. Transplacental transmission has also been reported.[4][5]

Epidemiology

Of the more than 100 Babesia species known to infect vertebrate animals, only a few have been documented to cause infection in humans. Ixodes ticks are the vector, and the primary reservoirs are typically small vertebrates such as rodents (particularly the white-foot mouse in the U.S.) and birds and the interaction between the vector and primary reservoir is required to complete the organism's life cycle. Larger mammals, particularly deer, sustain the adult population by providing a source of blood meal but are not reservoir hosts. Humans are accidental and dead-end hosts, and infections tend to occur in late spring through the fall in areas where humans are in proximity to ticks and their reservoirs. The majority of cases of Babesiosis in the United States occur in the Northeast (CT, MA, NJ, NY, RI) and upper Midwest (MN, WI) and are due to Babesia microti, transmitted by the Ixodes scapularis tick. The incidence of infection in this geographic area has been increasing. Babesiosis occurs sporadically in the Pacific Northwest, due to the Ixodes pacificus tick, and caused by the species Babesia duncani. In Europe, babesiosis is typically caused by Babesia divergens.[6][7][8]

Pathophysiology

The nymphal stage of the Ixodes is the primary vector and typically requires attachment to a host for at least 36 to 72 hours to complete a blood meal. If the tick is carrying the protozoa, the second or third day of attachment is typically when the babesia infection occurs with the transmission of sporozoite forms. These sporozoites attach and enter erythrocytes where they mature and divide via binary fission to form merozoites. These merozoites then leave the host erythrocyte, rupturing the cell, and go on to infect other erythrocytes, repeating the cycle above. The spleen is essential in the host's ability to control this infection. Erythrocytes infected with Babesia are recognized as abnormal as they pass through the spleen and are targeted for destruction by macrophages. People with a history of splenectomy are at high risk for severe infection with high-level parasitemia. Other high-risk populations include those with HIV, older than 50 years, neonates, and immunosuppressed patients (particularly TNF inhibitors or CD20 antibody).

History and Physical

The clinical presentation of babesiosis can range from asymptomatic to severe infection causing multi-organ failure. The severity of infection is often dependent on the immunocompetence of the host. The asymptomatic infection has been reported in up to 20% of adults and 50% of children. The incubation period has been reported to be typically between one to six weeks. Symptomatic illness in patients without immunodeficiencies usually consists of a febrile, flu-like illness often with a chill, sweats, malaise, fatigue, and headache. Other less common symptoms include a cough, arthralgia, sore throat, abdominal pain, nausea, emotional lability, and depression. On exam, apart from fever, patients may have hepatosplenomegaly, jaundice, retinopathy, or pharyngeal erythema. A rash is not a common symptom and may indicate co-infection with Lyme disease. Severe disease typically occurs only in high-risk populations mentioned above, particularly in those with a history of asplenia. These patients may have multi-organ dysfunction, including respiratory distress, congestive heart failure, renal failure, splenic rupture, disseminated intravascular coagulation (DIC), hepatitis, or coma.

Evaluation

The diagnosis of babesiosis is typically made by identifying the organism on a thin smear of peripheral blood, using Giemsa or Wright staining, and the severity of parasitemia can be assessed. In early infection, it is recommended that multiple thin smears be examined as parasite burden may be low initially. Ring forms are most commonly seen and can have multiple rings per cell. Tetrad formations, also known as Maltese cross, are occasionally seen. PCR testing is also available at reference laboratories and is more sensitive than peripheral smears. Serology is performed via indirect immunofluorescent antibody testing and can be useful for confirming the diagnosis. A single positive serology cannot distinguish between acute and previous infection, but a four-fold rise in acute and convalescent titers confirms a recent infection. Lab abnormalities that may be seen in babesiosis include anemia, elevated LDH, thrombocytopenia, transaminitis, proteinuria and elevated BUN and creatinine. [9]

Treatment / Management

[10]Treatment is indicated in symptomatic cases or in asymptomatic patients who have a positive blood smear or PCR for more than three months. There are two regimens used for treatment in mild to moderate disease. The first and most commonly used regimen is atovaquone plus azithromycin. The other option is quinine plus clindamycin which has much higher rates of adverse drug reactions compared to atovaquone/azithromycin (72% versus 15% respectively). A 7- to 10-day course of either regimen is recommended. Severe disease, requiring hospitalization or causing organ failure, typically occurs in high-risk populations or in those infected with the B. divergens species. These patients require treatment with clindamycin plus quinine (IV quinidine may also be used, but patient require monitoring for QT prolongation). The duration of treatment is at least 7 to 10 days but is based on clinical and laboratory response. Some of these patients with immunocompromising conditions will have a persistent or relapsing disease, in which case, a course of at least six weeks is recommended, with treatment continued for at least two weeks after parasites are no longer detected on blood smears. For patients who fail to respond to standard therapy, other regimens have been used including atovaquone plus azithromycin plus clindamycin; atovaquone plus azithromycin plus doxycycline; and atovaquone plus clindamycin plus doxycycline. No particular anti-parasitic combination therapeutic drug regimen has demonstrated superiority.  If possible, it is also recommended to reduce underlying immunosuppression. 

Partial or complete red blood cell (RBC) exchange transfusion is indicated in patients presenting with parasitemia of at least 10% and anemia with hemoglobin of <10 g/dL. Consideration for exchange transfusion should be strongly given in those with infection due to B. divergens pulmonary, renal or hepatic dysfunction, regardless of parasitemia level.[11][12]

Pearls and Other Issues

Babesiosis became a reportable disease in the United States in January 2011, and its incidence has been increasing, due in part to a geographic expansion of the vector.  Because Ixodes scapularis is also the vector for Borrelia burgdorferi and Anaplasma phagocytophilum, coinfections do occur and should especially be considered in patients failing to improve on therapy.

Enhancing Healthcare Team Outcomes

Babesiosis is a rare tick-borne infection with a varied presentation. The organism can affect many organ systems and is best managed by a multidisciplinary team. As soon as the infection is diagnosed, it has to be reported to the local public health authority and the infectious disease expert should be consulted on management.  Delayed diagnosis can lead to a high morbidity and mortality.


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Babesiosis - Questions

Take a quiz of the questions on this article.

Take Quiz
Which statement about babesiosis is false?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is the vector for transmission of babesiosis to humans?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A twelve year old boy from Florida presents to his provider in August with complaints of fevers, chills, myalgia, headache and arthralgia of 2 days durations. 6 months ago he vacationed with his family in Massachusetts, but that has been his only travel outside the state in the past year. One month ago he had an appendicitis, requiring appendectomy and a blood transfusion. Labs show anemia, thrombocytopenia, and elevated transaminases. Ring forms are seen on a peripheral blood smear and PCR is positive for babesiosis. What is the most likely source of his infection?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
An otherwise healthy male is diagnosed with babesiosis about 1.5 weeks following a hiking trip in Upstate New York. He is started appropriately on treatment by his provider with atovaquone and azithromycin. About 4 days into his treatment, he returns in follow up with ongoing complaints of fatigue, malaise and headaches. He also notices a new rash on his arm. What is the most likely cause of his current symptoms.



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of these antimicrobials is NOT recommended for treatment of babesiosis?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 17-year old female from Connecticut presents with a 7-day history of fever and chills. In the last 48 hours, she has also developed malaise, anorexia and muscle pain. Her physical exam is unremarkable except for a few petechiae. She was hiking in the woods recently where there were many ticks and insects. The physical exam is unremarkable. Testing for Lyme disease is negative, but the infectious disease expert feels that she may have been bitten by the deer tick "Ixodes dammini." Which other disease, besides Lyme, can be caused by this same tick?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Babesiosis - References

References

Patel KM,Johnson JE,Reece R,Mermel LA, Babesiosis-Associated Splenic Rupture: Case Series from a Hyperendemic Region. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2018 Dec 12     [PubMed]
Tonnetti L,Townsend RL,Deisting BM,Haynes JM,Dodd RY,Stramer SL, The impact of Babesia microti blood donation screening. Transfusion. 2018 Nov 30     [PubMed]
Beard CB,Occi J,Bonilla DL,Egizi AM,Fonseca DM,Mertins JW,Backenson BP,Bajwa WI,Barbarin AM,Bertone MA,Brown J,Connally NP,Connell ND,Eisen RJ,Falco RC,James AM,Krell RK,Lahmers K,Lewis N,Little SE,Neault M,Pérez de León AA,Randall AR,Ruder MG,Saleh MN,Schappach BL,Schroeder BA,Seraphin LL,Wehtje M,Wormser GP,Yabsley MJ,Halperin W, Multistate Infestation with the Exotic Disease-Vector Tick Haemaphysalis longicornis - United States, August 2017-September 2018. MMWR. Morbidity and mortality weekly report. 2018 Nov 30     [PubMed]
Abraham A,Brasov I,Thekkiniath J,Kilian N,Lawres L,Gao R,DeBus K,He L,Yu X,Zhu G,Graham M,Liu X,Molestina R,Ben Mamoun C, Establishment of a continuous {i}in vitro{/i} culture of {i}Babesia duncani{/i} in human erythrocytes reveals unusually high tolerance to recommended therapies. The Journal of biological chemistry. 2018 Nov 21     [PubMed]
Villatoro T,Karp JK, Transfusion-Transmitted Babesiosis. Archives of pathology     [PubMed]
Leiby DA,O'Brien SF,Wendel S,Nguyen ML,Delage G,Devare SG,Hardiman A,Nakhasi HL,Sauleda S,Bloch EM, International survey on the impact of parasitic infections: frequency of transmission and current mitigation strategies. Vox sanguinis. 2018 Dec 6     [PubMed]
Rautenbach Y,Schoeman J,Goddard A, Prevalence of canine Babesia and Ehrlichia co-infection and the predictive value of haematology. The Onderstepoort journal of veterinary research. 2018 Oct 9     [PubMed]
Gray JS,Estrada-Peña A,Zintl A, Vectors of Babesiosis. Annual review of entomology. 2018 Oct 1     [PubMed]
Hoversten K,Bartlett MA, Diagnosis of a tick-borne coinfection in a patient with persistent symptoms following treatment for Lyme disease. BMJ case reports. 2018 Sep 27     [PubMed]
Lempereur L,Beck R,Fonseca I,Marques C,Duarte A,Santos M,Zúquete S,Gomes J,Walder G,Domingos A,Antunes S,Baneth G,Silaghi C,Holman P,Zintl A, Guidelines for the Detection of Babesia and Theileria Parasites. Vector borne and zoonotic diseases (Larchmont, N.Y.). 2017 Jan     [PubMed]
Choi E,Pyzocha NJ,Maurer DM, Tick-Borne Illnesses. Current sports medicine reports. 2016 Mar-Apr     [PubMed]
Paparone P,Paparone PW, Variable clinical presentations of babesiosis. The Nurse practitioner. 2018 Oct     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Dermatology. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Dermatology, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Dermatology, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Dermatology. When it is time for the Dermatology board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Dermatology.