A-Z Index × Submit A-Z Index × Submit A-Z Index Search Dropdown × Submit Facebook Twitter LinkedIn Syndicate Emerging Infectious Disease journal ISSN: 1080-6059 Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
We describe a fatal Rickettsia parkeri rickettsiosis case in a 3-year-old boy in Georgia, USA, receiving chemotherapy for B-cell acute lymphoblastic leukemia, hospitalized with febrile neutropenia. Plasma microbial cell-free DNA sequencing confirmed the diagnosis. This report highlights the need to maintain suspicion for tickborne diseases in immunocompromised hosts in some settings.
Rickettsia parkeri rickettsiosis is a mild to moderately severe spotted fever rickettsiosis (SFR) characterized by fever, myalgias, headache, rash, and, commonly, an eschar at the site of tick attachment ( 1 ). Since 2020, nearly 5,000 cases of SFR have been reported in the United States, including infections with R. parkeri ( 2 ). A systematic review of 77 R. parkeri rickettsiosis cases found that only 9% (16% in confirmed cases) required hospitalization and only 7% (3% in confirmed cases) occurred in children ( 3 ). Doxycycline is the treatment of choice for all rickettsial infections. We describe a fatal case of R. parkeri infection in an immunocompromised child in Georgia, USA.
Figure 1 . Photographs of rash from study of fatal Rickettsia parkeri rickettsiosis in immunocompromised pediatric patient, Georgia, USA, 2025. A) Eschar on left upper extremity; B) rash on patient’s torso.
A 3-year-old boy from southwestern Georgia receiving chemotherapy for high-risk B-cell acute lymphoblastic leukemia was admitted to the hospital in late July 2025 with febrile neutropenia. At admission, he had profound neutropenia and thrombocytopenia (leukocyte count 110/µL, absolute neutrophil count 20/µL, platelets 19,000/µL). He was on the second month of delayed intensification chemotherapy as part of a high-risk B-cell acute lymphoblastic leukemia regimen and had received cyclophosphamide, cytarabine, and 6-thioguanine 2 weeks before admission. His examination was unremarkable except for 2 pink papulonodules with central eschars on the left upper extremity ( Figure 1 , panel A). He was started on empiric cefepime therapy after blood cultures were obtained.
On the second and third day of hospitalization, a rash developed that began with small pink macules on the upper back and arms ( Figure 1 , panel B). Over the next 3 days, the rash progressed to numerous pink macules, some with overlying vesicles involving the bilateral upper and lower extremities, face, and trunk. Upon further questioning, his parents reported that the lesions on his left arm had been present for about 1 month before hospitalization and had been draining clear fluid. They attributed those lesions to suspected insect bites because he frequently played in the grass around their suburban home, but they did not recall seeing any insects.
He remained febrile despite cefepime therapy and had persistent pancytopenia and unmeasurable lymphocyte count; blood culture results were negative. Micafungin and acyclovir were initiated to target potential disseminated infection with Candida or herpes viruses. PCR testing for herpes simplex virus and varicella zoster virus from an unroofed vesicle returned negative results. Computed tomography with intravenous contrast of the lungs sh…