Atypical Chikungunya Virus Infections in Immunocompromised Patients

To the Editor: Chikungunya fever was fi rst described in Tanganyika (now Tanzania) in 1952 and is now emerging in Southeast Asia. Chi-kungunya virus (CHIKV) infection, a self-limiting febrile illness, shares similarities with dengue fever such as headache and myalgia. Additionally , patients with CHIKV infection typically have arthralgia, arthritis, and tenosynovitis (1). Although usually benign, CHIKV infection may on rare occasions lead to neurologic and hepatic manifestations with high illness and mortality rates (2). We report 2 immunocompromised patients with CHIKV infection associated with peritonitis, encephalitis, and secondary bacterial infections. Patient A, a 66-year-old Singa-porean-Chinese man, had a history of chronic renal disease secondary to obstructive uropathy. His baseline creatinine level was 300–400 μmol/L. For 3 years, he had ingested traditional Chinese medicine, which we suspect was contaminated by steroids because he appeared cushingoid. An outbreak of CHIKV infection was reported at his workplace. He was admitted to National University Hospital , Singapore, in July 2008 with abdominal pain, vomiting, and fever of 1 day. He had no joint symptoms. Clinically, he had systemic infl amma-tory response syndrome complicated by acute-on-chronic renal failure. His creatinine level was elevated at 921 μmol/L on admission. A complete blood count showed leukocytosis (19.24 × 10 9 cells/L) with neutro-philia and thrombocytopenia (62 × 10 9 cells/L). Initial blood and urine cultures and serologic results were negative for dengue virus, but serum reverse transcription–PCR (RT-PCR) and indirect immunofl uorescent assay for immunoglobulin G (IgG) were positive for CHIKV (3,4). Computed tomographic scans of the abdomen showed dilated small bowel loops. An urgent laparotomy did not show bowel perforation, but peritone-al cultures yielded Klebsiella pneumo-niae, Escherichia coli, and Candida glabrata, and RT-PCR from the concentrated peritoneal fl uid was positive for CHIKV (3). He was administered appropriate antimicrobial drugs. He required repeat laparotomies because of elevated intraabdominal pressure. He subsequently received broad spectrum antimicrobial drugs to treat secondary intraabdominal infections caused by P. aeruginosa and Entero-coccus faecalis. Ventilator-associated pneumonia also developed. Despite maximal support and prolonged antimicrobial therapy , this patient died after 5 months of hospitalization. Patient B, a 45-year-old Ma-laysian–Chinese man with diabetes mellitus, had undergone a cadaveric liver transplant in 2001 for hepatitis B liver cirrhosis. He was receiving immunosuppressants (azathioprine and prednisolone). He was admitted in August 2008 after experiencing fever , headache, and abdominal bloating for 3 days. He had no neurologic symptoms. Acute self-limiting febrile illnesses with arthritis …