[Meningoencephalitis caused by West Nile virus in a renal transplant recipient]

West Nile virus (WNV) infection which is asymptomatic or mild in normal population, it may cause serious clinical conditions leading to death in eldery and immunosupressed patients. The virus is mainly transmitted by mosquito bites, however transfusion, transplantation, transplasental and nosocomial ways have also been reported to be responsible for viral transmission. It is known that WNV may cause life-threatining conditions such as central nervous system (CNS) infections especially in bone marrow and solid organ transplant recipients. In this report, the first case of WNV encephalitis in an immunosuppressed patient with renal transplant in Turkey was presented. A 25-year-old male patient admitted to our hospital with the complaints of generalized myalgia, nausea and vomiting, after the 24. day of renal transplantation from a live donor. Since he developed diffuse tonic clonic seizures during his follow up, he was diagnosed as meningoencephalitis with the results of cranial magnetic resonance imaging (MR) and cerebrospinal fluid (CSF) biochemistry. Bacterial and fungal cultures of blood and CSF yielded negative results. CMV antigenemia test and CMV IgM in blood, and nucleic acid tests for CMV, EBV, HSV-1/2, VZV, HHV-6, enterovirus and parvovirus in CSF were also negative. However, WNV RNA was detected in CSF by an in-house reverse transcriptase (RT) nested PCR method. The sequence analysis (GenBank BLAST) of the virus showed that it had 99% similarity with Lineage-1 WNV strains. To define the transmission way of the virus to the recipient, WNV-RNA was searched in the renal biopsy sample and found negative by RT nested PCR. The clinical condition of the patient was improved with supportive therapy and by the de-escalation of immunosuppressive drugs [Mycophenolate mofetil (MMF; 1 g/day), cyclosporin (1 mg/kg/day)]. However WNV meningoencephalitis recurred one month later. The patient presented with fever, myalgia, confusions, leukocytosis, anemia, and repeating WNV-RNA positivity in CSF. This time cyclosporin was stopped, MMF was given in low dose (1 g/day), and high dose parenteral acyclovir and intravenous immunoglobulin (400 mg/kg/day, 7 days) were initiated. The patient recovered completely after 10 days without any neurological abnormalities. In conclusion, especially in endemic areas, WNV should be considered in the differential diagnosis of CNS infections develop in solid organ transplant cases and patients with other immunodeficiencies who present with fever, generalized myalgia, gastrointestinal symptoms and/or neurological disorders.