Acute encephalopathy caused by defective virus infection. I. Studies of Newcastle disease virus infections in newborn and adult mice

Coma associated with intense bursts of abnormal movements and long-lasting cognitive disturbances: an acute encephalopathy of obscure origin

We report six previously healthy children who several days after a prodromal illness had an acute encephalopathy that ran a biphasic course. It appears to constitute a recognizable syndrome with a good prognosis that can be differentiated from other encephalopathies of obscure origin as previously defined by Lyon et al. The active phase was dominated by coma or confusion and by abnormal movements, including disordered gesticulation and attacks of orofacial dyskinesia or limb dystonia associated with permanent rigidity and culminating in opisthotonic posturing. Repeated seizures were observed in only two patients. Permanent slow waves were recorded on the electroencephalogram in all patients, even during bursts of abnormal movements. Cerebrospinal fluid and results of serologic studies were normal throughout the course of the disease, and attempts at viral isolation and antiviral antibody detection yielded negative results. Brain imaging either showed no abnormalities or suggested a moderate degree of brain edema. The recovery phase, which extended for several weeks, was characterized by a rapid return of motor function and persistent behavioral and cognitive disturbances. Nonverbal reasoning recovered long before verbal expression returned to normal. Four patients eventually recovered fully, whereas two had mild sequelae.

Elemental analysis in murine central nervous system: elevation of rubidium subsequent to Newcastle disease virus encephalopathy

The Cg strain of Newcastle disease virus (NDV) produces neurologic signs and death in mice. This illness is unusual because of the lack of typical features of a viral encephalitis. Specifically, there is a paucity of infectious virus, detectable cellular inflammatory reaction, cytopathic effect, and viral antigen by immunofluorescence. We previously showed an elevation of alpha-aminoisobutyric acid in the CNS of moribund NDV-infected mice, indicating cellular membrane dysfunction. In an attempt to further our understanding of the pathogenesis of the illness, we evaluated CNS concentrations of sodium, potassium, iron, copper, zinc, magnesium, selenium, and rubidium. Elemental analysis revealed no difference between infected and control mice for all elements except for rubidium, which was significantly elevated in infected mice. Elevation in rubidium was detected in infected mice by X-ray fluorescence and atomic absorption spectrophotometry, whereas rubidium concentrations for control mice were similar by both methods. Neurologic symptoms correlated directly with rising rubidium concentrations. Our data suggest that abnormal trace element levels during viral infection may be one mechanism responsible for the clinical symptoms.

Non-productive paramyxovirus infection: Nariva virus infection in hamsters

The pathogenesis of infection with Nariva virus (NV)--recently classified as a paramyxovirus--was studied in the hamster, an animal closely related to the natural host. Intracranial inoculation of suckling hamsters produces an acute necrotizing encephalitis with large amounts of infectious virus and virus antigen in the brain. In contrast, weanling hamsters have only small amounts of infectious virus and only early in the disease, when they are well; later, when clinically ill, they have a non-productive infection with continuing evidence of viral antigen, but no detectable infectious virus. Weanlings die later than sucklings with less cerebral parenchymal necrosis. The integrity of the immune system affects the expression of NV since brain tissue from anti-lymphocyte serum (ALS) treated infected weanling hamsters have more infectious virus, and for longer periods, than brain tissue from untreated infected weanling hamsters. Changing susceptibility of the host's neural cells may also be involved in determining the course of the illness and expression of the virus since: 1) ALS treatment does not influence the clinical course of the disease or pathology, 2) ALS treated weanlings still have much lower levels of infectious virus than sucklings, 3) infected weanling and suckling hamsters have a similar time course of development of NV neutralizing antibody.