First Reported Case of Ehrlichia ewingii Involving Human Bone Marrow

Abstract

A 65-year-old female with a history of multiple tick bites presented with fever and pancytopenia. Intracytoplasmic rickettsial morulae were detected on peripheral smear and bone marrow biopsy specimens, and PCR amplified Ehrlichia ewingii DNA from both specimens. To our knowledge, this is the first report of E. ewingii infection of human bone marrow. CASE REPORTA 65-year-old female from rural north-central Arkansas presented in July to an emergency department with weakness and fatigue. She had a 5-day history of subjective fever, productive cough, generalized myalgia, and progressive fatigue. She denied nausea, diarrhea, bleeding, and rash but stated that she had had a urinary tract infection (UTI) 1 month prior that had been treated with sulfamethoxazole-trimethoprim without resolution. She reported multiple recent tick bites while working in her yard and was in close contact with several pet dogs.Past medical history was significant for type 2 diabetes mellitus, hypertension, hypothyroidism, and laryngeal squamous carcinoma that had been in remission since treatment with chemotherapy and radiation 2 years prior to presentation. The physical examination was significant for fever of 101.3°F and bilateral upper extremity petechiae and bruising.Initial laboratory studies revealed a white blood count (WBC) of 2,000/l (reference range, 3,000 to 12,000/l), a hemoglobin level of 8.9 g/dl (reference range, 11.5 to 16 g/dl), and a platelet count of 32,000/l (reference range, 150,000 to 500,000/l). Each of these values had been within normal limits during an evaluation for her UTI that had been performed 3 weeks earlier. The total bilirubin level was 1.3 mg/dl (reference range, 0.2 to 1.2 mg/dl), and the lactate dehydrogenase level was 314 IU/liter (reference range, 100 to 248 IU/liter). Iron studies showed a decreased total iron binding capacity of 234 g/dl (reference range, 250 to 425 g/dl) and an increased peripheral blood ferritin level of 732 g/dl (reference range, 11 to 306 g/dl) with normal iron and folate levels. The antinuclear antibody (ANA) titer was increased at 1:160. Random-inpatient blood glucose levels ranged from 102 to 111 mg/dl, and her diabetes was adequately controlled with metformin and glipizide by her treatment as an outpatient. HIV serology results were negative.The patient was admitted to the hospital and was started on vancomycin and cefepime because of fever and neutropenia and was started on doxycycline to address the potential for tick-borne illness. Since recurrent malignancy, myelodysplastic syndrome following chemotherapy, and other marrow processes were in the differential diagnosis for her pancytopenia, peripheral smear and bone marrow aspirate and core biopsy procedures were performed. Review of the peripheral blood smear revealed leukopenia with neutrophilic bands containing intracytoplasmic morulae (Fig. 1), pancytopenia with leftshifted granulopoiesis, reactive lymphocytes, a relative monocytosis, thrombocytopenia, and mild erythrocyte anisopoikilocytosis. The marrow aspirate showed...

Increasing Incidence of Ehrlichiosis in the United States: A Summary of National Surveillance of Ehrlichia chaffeensis and Ehrlichia ewingii Infections in the United States, 2008–2012

“…Previous case reports suggested E. ewingii primarily affects those who are immunocompromised, which may be because immunocompromised persons are more likely to develop serious infections, be hospitalized, and have extensive laboratory diagnostic tests. 2,7,8,15,17,34 In addition, because E. ewingii is a milder illness, it is possible that immunocompetent patients may have less severe symptoms and not seek medical attention, which may have led to overrepresentation of immunocompromised cases in previous reports. In our report, the prevalence of reporting an immunosuppressive condition was 26% among E. ewingii cases; cases with E. ewingii infections reporting an immunocompromised condition were more likely to be hospitalized.…”

“…4,5 Human ehrlichiosis caused by E. ewingii is less commonly reported and most infections have historically occurred among immunocompromised patients. 2,[6][7][8][9] Symptoms of ehrlichiosis are nonspecific and typically begin within 7-14 days of exposure. 6 Patients are most likely to seek medical attention approximately 3 days after onset of symptoms.…”

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

“…Sensitivities might be higher for tests using eschars than for those using rash lesions (269) because of the higher concentration of organisms in eschars compared with rash lesions. In cases of ehrlichiosis or anaplasmosis in which bone marrow biopsies are performed as part of the investigation of cytopenias, immunostaining of bone marrow biopsy specimens can reveal the diagnosis (156,160). Immunostaining can be particularly useful for diagnosing fatal tickborne rickettsial diseases in tissue specimens from patients who had not developed diagnostic levels of antibodies before death (16,141,293,300).…”

“…Similar to E. chaffeensis ehrlichiosis, patients with E. ewingii ehrlichiosis commonly have leukopenia, thrombocytopenia, and elevated hepatic transaminase levels. E. ewingii has a predilection for granulocytes, and morulae might be observed in granulocytes during examination of a blood smear, bone marrow, or CSF (48,160) (Figure 28). …”

Relative Risk for Ehrlichiosis and Lyme Disease in an Area Where Vectors for Both Are Sympatric, New Jersey, USA

“…Because ehrlichiosis cases have steadily increased since becoming reportable (13,15), the spread of A. americanum ticks and the emergence of ehrlichiosis as a human pathogen in the United States may parallel increases in I. scapularis tick populations and the emergence of Lyme disease that occurred 30 years prior (14). Even if most unrecognized infections are mild or asymptomatic, these could still have consequences for public health; for example, blood donors who are unknowingly infected could pass the infection to immunocompromised patients (45), or prescription of sulfa drugs for unrelated ailments could result in worsened disease presentation (46).…”