Ehrlichia chaffeensis in Child, Venezuela

To the Editor: Human mono-cytic ehrlichiosis is a tick-borne infectious disease caused by Ehrlichia chaffeensis (1). Serologic studies have indicated E. chaffeensis infection in Latin American countries: Venezuela (2), Mexico (3), Argentina (4), Chile (5), and Brazil (6). However, no molecular evidence for E. chaffeensis has been reported. In December 2001, a 9-year-old boy was admitted to a hospital in Carabobo, Venezuela, after 3 days of fever (39°C–41°C), malaise, an-orexia, headache, abdominal pain, and cutaneous tick-bite lesions. During the 6 weeks before admission, the patient had been exposed to ticks in a rural area (Cojedes, Venezuela). At the time of physical examination, the patient appeared acutely ill with fever (41°C), dehydration, somnolence, conjunctivitis, facial edema, cervical adenomegaly, soft depressible abdomen painful to palpation, and hepa-tomegaly. Cardiopulmonary examination found regular cardiac sounds with systolic tricuspid murmur and abnormal bilateral respiratory sounds (rhonchi). Skin examination showed multiple tick bites and an erythema-tous maculopapular rash. Appropriate informed consent was obtained. Blood values were as follows: leukocytes 6,280 cells/mm 3 (84% neutrophils, 13% lymphocytes, 2% monocytes, 1% eosinophils), platelets 130,000/μL, hemoglobin 12.5 g/dL, glucose 102 mg/dL, blood urea 28.3 mg/dL, creatinine 0.9 mg/dL, aspar-tate aminotransferase (AST) 20.4 U/L, alanine aminotransferase (ALT) 54.4 U/L, erythrocyte sedimentation rate (Katz index) 15 mm/h, prothrombin time ratio 1.02, partial thromboplastin time –2.8 s. Radiographs of the thorax showed bilateral infi ltrate. Echocar-diogram showed minor tricuspid in-suffi ciency. Serologic tests were negative for Epstein-Barr and hepatitis B and positive for cytomegalovirus and hepatitis A viruses. Blood and stool cultures were negative. Blood samples were taken 4 and 35 days after illness onset; buffy-coat smears were stained with Dip Quick immunologic and PCR tests were performed. Immunoglobulin (Ig) M against dengue virus was present at days 4 and 35 of illness; IgG against dengue was absent on day 4 and present on day 35. PCR and viral isolation tests for dengue virus were negative. Serologic tests for E. chaffeensis (indirect immunofl uorescence) were also negative on day 4 and positive (256) on day 35. Detection of Ehrlichia spe-cies–specifi c DNA was performed by using nested PCR as described (7). Starting on the fi rst day of hospitalization , the patient was treated with doxycycline (14 days) and chloram-phenicol (8 days). After 24 hours, malaise , headache, facial edema, and conjunctivitis improved. After 48 hours, fever and rash were gone. After 3 days, his appetite improved; progressively over time, cervical adenomegaly …