title: Autonomic deficit not the cause of death in West Nile virus neurological disease.
abstract: BACKGROUND
  Some West Nile virus (WNV)-infected patients have been reported to manifest disease signs consistent with autonomic dysfunction. Moreover, WNV infection in hamsters causes reduced electromyography amplitudes of the gastrointestinal tract and diaphragm, and they have reduced heart rate variability (HRV), a read-out for the parasympathetic autonomic function.
  
  
  METHODS
  HRV was measured in both hamsters and mice using radiotelemetry to identify autonomic deficits. To identify areas of WNV infection within the medulla oblongata mapping to the dorsal motor nucleus of vagus (DMNV) and the nucleus ambiguus (NA), fluorogold dye was injected into the cervical trunk of the vagus nerve of hamsters. As a measurement of the loss of parasympathetic function, tachycardia was monitored contiguously over the time course of the disease.
  
  
  RESULTS
  Decrease of HRV did not occur in all animals that died, which is not consistent with autonomic function being the mechanism of death. Fluorogold-stained cells in the DMNV were not stained for WNV envelope protein. Fourteen percent of WNV-stained cells were co-localized with fluorogold-stained cells in the NA. These data, however, did not suggest a fatal loss of autonomic functions because tachycardia was not observed in WNV-infected hamsters.
  
  
  CONCLUSIONS
  Parasympathetic autonomic function deficit was not a likely mechanism of death in WNV-infected rodents and possibly in human patients with fatal WN neurological disease.
authors.affiliation: Department of Animal, Dairy, and Veterinary Sciences, School of Veterinary Medicine, Institute for Antiviral Research, Utah State University, 4700 Old Main Hill, Logan, UT, 84322-4700, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Venkatraman
authors.initials: V
authors.lastname: Siddharthan
authors.forename: Jeffery O
authors.initials: JO
authors.lastname: Hall
authors.forename: John D
authors.initials: JD
authors.lastname: Morrey
mesh_terms: D000818:Animals; D001342:Autonomic Nervous System Diseases / Q000401:mortality* / Q000503:physiopathology* / Q000821:virology; D002423:Cause of Death; D006224:Cricetinae; D004195:Disease Models, Animal; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008647:Mesocricetus; D051379:Mice; D008810:Mice, Inbred C57BL; D011897:Random Allocation; D014901:West Nile Fever / Q000401:mortality* / Q000503:physiopathology*; D014902:West Nile virus