David Ben-Nathan

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West Nile virus (WNV) is a mosquito-borne disease found most commonly in Africa, West Asia, and the Middle East, where up to 40% of the human population possesses antibodies. It is an emerging disease in the United States. Humans infected with WNV develop a febrile illness that can progress to meningitis or encephalitis. In mice, WNV causes central nervous(More)
Since smallpox eradication by the WHO during the 1980s, potency of new vaccines is compared to vaccines that were used during the eradication campaign. In this work we characterize the tail scarification technique in mice as a model for scarification in humans. Similar to humans, mice develop "clinical take" which is dependent on the vaccination dose.(More)
Vaccinia virus protein A33 (A33VACV) plays an important role in protection against orthopoxviruses, and hence is included in experimental multi-subunit smallpox vaccines. In this study we show that single-dose vaccination with recombinant Sindbis virus expressing A33VACV, is sufficient to protect mice against lethal challenge with vaccinia virus WR(More)
Newcastle disease (ND) is a worldwide problem with severe economic implications, affecting chickens, turkeys and other birds. Newcastle disease virus (NDV), a member of the Paramyxoviridae group can cause disease of diverse severity in accordance with environmental factors. NDV strains are classified according to their virulence into three categories. The(More)
The protective effect of pretreatment with dehydroepiandrosterone (DHEA) on stress-enhanced viral encephalitis was studied in mice exposed to cold following inoculation with West Nile virus (WNV). Exposure of WNV-inoculated mice to cold water (1 +/- 0.5 degrees C, 5 minutes/day for 8 days) resulted in a mortality rate of 83% as compared to 50% in(More)
Recent reports have demonstrated an immunomodulating activity of dehydroepiandrosterone (DHEA) different from that described for glucocorticoids. The present study was designed to test DHEA's activity in endotoxic shock and to investigate its effect on endotoxin-induced production of tumor necrosis factor (TNF). Mortality of CD-1 mice exposed to a lethal(More)
There are contradictory reports regarding the effects of inhalation anesthetics on the immune system. Measurable immune responses have been studied in vitro, but little is known about the in vivo effects in the intact organism. We used an attenuated, non-neuroinvasive, nonlethal strain of the encephalitic West Nile virus, termed WN-25, which can become(More)
The effects of inhalational anesthetics on brain penetration by the neurovirulent noninvasive West Nile virus (WN-25) were studied in mice. WN-25 injected intracerebrally causes encephalitis and kills adult mice, but when injected intraperitoneally (i.p.) it is unable to invade the brain and kill. Under stress conditions, this strain causes encephalitis and(More)
Marek's disease (MD) is one of the viral infections that attack poultry and are widespread throughout the world. Vaccination is widely used for the protection of chickens against outbreaks of MD, and commercial vaccines have been used since 1970. There are vaccines derived from three avian herpesvirus serotypes which are propagated in CEF or DEF cell(More)
The present study was designed to test the effect of bacterial endotoxin on penetration of viruses into the central nervous system (CNS). As a model we used two neurovirulent viruses that lack neuroinvasive capacity: West Nile virus-25 (WN-25) and neuroadapted Sindbis virus (SVN). Administration of lipopolysaccharide (LPS, 100 micrograms/mouse) to CD-1(More)