# A Presentation of Babesiosis in the Setting of Low-Grade Follicular B-cell Lymphoma

## TL;DR

This case report discusses the diagnostic challenges of distinguishing babesiosis from low-grade lymphoma symptoms and suggests screening for babesiosis before immunosuppressive treatment.

## Contribution

The paper introduces a recommendation for babesiosis screening before rituximab treatment in patients with specific symptoms and geography.

## Key findings

- Babesiosis symptoms can mimic those of low-grade follicular B-cell lymphoma, making diagnosis difficult.
- Concurrent babesiosis and lymphoma can lead to diagnostic confusion and potential harm from immunosuppressive treatment.
- Screening for babesiosis before rituximab use is suggested to avoid confounding diagnoses.

## Abstract

Babesiosis is a tick-borne parasitic infection seen in the Northeast and upper Midwest regions of the United States. Clinically, this intra-erythrocytic parasitic infection can present in a variety of ways, including fever, fatigue, malaise, or myalgia. Of note, these presenting symptoms are very similar to symptoms that can also be seen in patients with low-grade lymphoma. Thus, differentiating between babesiosis infection and active, symptomatic low-grade lymphoma can be difficult. We present a patient with concurrent severe babesiosis infection and follicular lymphoma. This case report provides a unique overlap of Hematology/Oncology and Infectious Disease and the ensuing diagnostic challenges when both tick-borne illnesses and low-grade lymphoma present together. We suggest including babesiosis screening in the pretreatment evaluation for the use of rituximab in patients with the above symptomatology and geography. This will help rule out alternate confounding diagnoses of babesiosis infection before initiating immunosuppressive treatment for active, symptomatic low-grade lymphoma. Using immunosuppressive agents such as rituximab to treat suspected low-grade lymphoma, before ruling out tick-borne illnesses, can be harmful. Our goal is to reduce such instances.