Case Of West Nile Virus Encephalitis Research Articles

Emerging Threat: First Case of West Nile Virus Encephalitis in Peshawar, Pakistan

West Nile Virus (WNV), once confined primarily to Africa, is now an emerging communicable disease in Pakistan. Clinical cases and serological evidence of WNV infection have been documented in both human and animal populations in the Punjab and Sindh provinces of Pakistan. We report the first case of WNV encephalitis in an 80-year-old hypertensive and diabetic lady from district Peshawar. Sadly, the patient did not survive. This case highlights the importance of thinking of zebras in addition to horses when confronted with the sound of hoofbeats, as ‘zebra diagnoses’ do exist. Clinicians shall consider novel infections when evaluating patients with fever and altered mental status.

Böbrek Nakli Alıcısında Batı Nil Virusuna Bağlı Meningoensefalit

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.

A Case of Central Nervous System Infection Due to West Nile Virus Lineage-1 in Ankara Province, Turkey

West Nile virus (WNV) is a mosquito-borne Flavivirus (family Flaviviridae), maintained in an enzootic cycle between birds as amplifying hosts and mosquito vectors. While WNV exposure in humans frequently remain subclinical, a febrile illness called West Nile fever occurs in about 20% and neuroinvasive disease in less than 1% of the affected individuals. For the last two decades, WNV has caused outbreaks of severe neuroinvasive disease in humans and horses in Europe, the Mediterranean Basin and emerged in the American continent. Although, previous serosurveillance reports have revealed human WNV exposure in various regions in Turkey; well-characterized clinical cases have only been reported after 2009-2010. In this report, a case of WNV encephalitis caused by a Lineage 1 virus strain and identified in Ankara province, Central Anatolia, Turkey, was presented. An 87 year-old woman with a history of hypertension and a recent febrile episode was admitted to Hacettepe University Hospital in late May 2012, with altered consciousness, myoclonic jerks in facial muscles and left extremity. Hyponatremia and increased alanine and aspartate aminotransferase levels were noted in blood analyses. Initial electroencephalogram (EEG) demonstrated diffuse slow waves. Areas of restricted diffusion in right dorsal thalamus was observed in cranial magnetic resonance imaging (MRI). Despite supportive therapy, the patient's neurological condition worsened. Follow-up EEG displayed paroxysmal lateralizing epileptiform discharges (PLEDs) in the right hemisphere and T2-hyperintense lesions in the right temporoparietal cortex, insula and thalamus with components of cytotoxic and vasogenic edema were observed in MRI. A cerebrospinal fluid (CSF)-serum pair was evaluated to identify potential causes of encephalitis. CSF biochemical and microscopic findings were within normal limits except for decreased glucose levels. Bacterial, mycobacterial and fungal cultures, antigen assays and polymerase chain reaction (PCR) employed for Herpes simplex virus types 1 and 2 were negative. Commercial and in house assays for WNV, tick-borne encephalitis virus, Toscana virus (TOSV) antibodies revealed TOSV IgG in serum. Previously described nested PCRs targeting WNV envelope glycoprotein and phlebovirus consensus sequences demonstrated WNV positive results in serum and CSF, which were further characterized via cycle sequencing of amplicons as WNV Lineage 1 Clade 1a. Four serum samples obtained within 23 days after the diagnosis were negative for viral RNA and specific antibodies via commercial assays and WNV plaque reduction neutralization assay. During follow-up with supportive therapy and anti-epileptics, the patient's general and neurological condition improved mildly and control EEG and MRI demonstrated regression of previous lesions. However, the patient passed away on the 10th week of hospital admission due to nosocomial infections. These findings confirmed the inital data which indicated the circulation of WNV Lineage 1 strains in Central Anatolia, Turkey. WNV seroconversion may be delayed or absent in elderly individuals without overt diseases associated with immunosuppression. Thus investigation of WNV RNA together with the specific serological tests may help the accurate diagnosis of suspected cases.