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Yellow fever virus (YFV) causes 30,000 deaths worldwide, despite the availability of a vaccine. There are no approved antiviral therapies for the treatment of YFV disease in humans, and, therefore, these studies were designed to investigate the anti-YFV properties of T-1106, a substituted pyrazine, in a hamster model of YFV disease. Intraperitoneal (i.p.) treatment with 100 mg/kg of body weight/day of T-1106 starting 4 h prior to virus inoculation and continuing twice daily through 7 days post-virus inoculation (dpi) resulted in significantly improved survival, alanine aminotransferase levels in the serum, weight gain, and mean day to death. Virus titer in the liver at 4 dpi was significantly reduced in treated animals, as determined by both quantitative real-time PCR and infectious cell culture assay. No toxicity (weight loss or mortality) was observed at a dose of 100 mg/kg/day in sham-infected control animals. The observed minimal effective dose of T-1106 was 32 mg/kg/day administered either by oral or i.p. treatment. Therapeutic treatment was effective in significantly improving survival when T-1106 was administered beginning as late as 4 days after virus challenge with twice-daily treatment for 8 days at a dose of 100 mg/kg/day. With favorable safety, bioavailability, and postviral challenge treatment efficacy, T-1106 was effective in the treatment of disease in hamsters infected with YFV and should be further studied for potential use as a therapy for human YFV disease.

Cidofovir (CDV) is an effective drug against viruses of theOrthopoxviridaefamily and is active in vitro against variola virus, the cause of smallpox. However, CDV-resistant poxviruses can be generated by repeated in vitro passage in the presence of suboptimal concentrations of CDV. To determine if mutations in the E9L polymerase gene could confer resistance to this nucleoside analog, this gene was sequenced from CDV-resistant vaccinia virus and found to encode five amino acid changes, centered on an N-terminal region associated with 3′→5′ exonuclease activity. Transfer of this mutant E9L gene into wild-type vaccinia virus by marker rescue sufficed to confer the resistance phenotype. E9L polymerase mutations occurred sequentially during passage in CDV, and an H296Y/S338F double mutant that conferred an intermediate CDV resistance phenotype was identified. In vitro, the marker-rescued CDV-resistant vaccinia virus containing all five mutations grew nearly as well as wild-type vaccinia virus. However, the virulence of this virus for mice was reduced, as 10- to 30-fold more CDV-resistant virus than wild-type virus was required for lethality following intranasal challenge. Cidofovir and hexadecyloxypropyl-cidofovir gave partial protection to mice infected with the virus when used at 50 and 100 mg/kg of body weight given as single treatments 24 h after virus exposure, whereas 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine (compound S2242) was completely protective at 25, 50, and 100 mg/kg/day when given daily for 5 days. These findings suggest that drug therapy for poxviruses may be complicated by drug resistance but that treatment of the infection with currently known compounds is possible.

Influenza is a highly infectious disease characterized by recurrent annual epidemics and unpredictable major worldwide pandemics. Rapid spread of the highly pathogenic avian H5N1 strain and escalating human infections by the virus have set off the alarm for a global pandemic. To provide an urgently needed alternative treatment modality for influenza, we have generated a recombinant fusion protein composed of a sialidase catalytic domain derived fromActinomyces viscosusfused with a cell surface-anchoring sequence. The sialidase fusion protein is to be applied topically as an inhalant to remove the influenza viral receptors, sialic acids, from the airway epithelium. We demonstrate that a sialidase fusion construct, DAS181, effectively cleaves sialic acid receptors used by both human and avian influenza viruses. The treatment provides long-lasting effect and is nontoxic to the cells. DAS181 demonstrated potent antiviral and cell protective efficacies against a panel of laboratory strains and clinical isolates of IFV A and IFV B, with virus replication inhibition 50% effective concentrations in the range of 0.04 to 0.9 nM. Mouse and ferret studies confirmed significant in vivo efficacy of the sialidase fusion in both prophylactic and treatment modes.

We examined RWJ-270201 in a lethal model of influenza in BALB/c mice. The aim was to delineate the pharmacodynamically linked variable for the drug. Challenge was performed with influenza virus A/Shongdong/09/93 (H3N2). Treatment was administered by gavage. Five doses (1 to 10 mg/kg of body weight) and three schedules (every 24, 12, and 8 h) were evaluated with 10 mice per group. There were 39 placebo-treated mice. Drug exposure was evaluated for infected mice. Exposures were calculated after population modeling of all the plasma concentration-time data simulataneously using the NPEM3 program. Evaluation of dose and schedule with Kaplan-Meier analysis and Cox proportional hazards modeling demonstrated that schedule offered no explanatory power relative to dose alone. Evaluation of peak concentration, trough concentration, and area under the concentration-time curve (AUC) by the same methods revealed that AUC was the dynamically linked variable. Again, schedule offered no further explanatory power when included in the model with AUC. This indicates that AUC is the linked variable and that the anti-influenza effect of RWJ-270201 is independent of schedule. We conclude that once-daily dosing of RWJ-270201 should be evaluated in clinical trials of influenza therapy.

We have recently described GS 4071, a carbocyclic transition-state analog inhibitor of the influenza virus neuraminidase, which has potent inhibitory activity comparable to that of 4-guanidino-Neu5Ac2en (GG167; zanamivir) when tested against influenza A virus replication and neuraminidase activity in vitro. We now report that GS 4071 is active against several strains of influenza A and B viruses in vitro and that oral GS 4104, an ethyl ester prodrug which is converted to GS 4071 in vivo, is active in the mouse and ferret models of influenza virus infection. Oral administration of 10 mg of GS 4104 per kg of body weight per day caused a 100-fold reduction in lung homogenate viral titers and enhanced survival in mice infected with influenza A or B viruses. In ferrets, a 25-mg/kg dose of GS 4104 given twice daily reduced peak viral titers in nasal washings and eliminated constitutional responses to influenza virus infection including fever, increased nasal signs (sneezing, nasal discharge, mouth breathing), and decreased activity. Consistent with our demonstration that the parent compound is highly specific for influenza virus neuraminidases, no significant drug-related toxicity was observed after the administration of oral dosages of GS 4104 of up to 800 mg/kg/day for 14 days in nonclinical toxicology studies with rats. These results indicate that GS 4104 is a novel, orally active antiviral agent with the potential to be used for the prophylaxis and treatment of influenza A and B virus infections.

The oxygen free-radical scavenger recombinant human manganese superoxide dismutase (MnSOD) was studied for its effects on influenza virus infections in mice when used alone and in combination with ribavirin. Mice challenged with influenza A/NWS/33 (H1N1) virus were treated parenterally in doses of 25, 50, and 100 mg/kg of body weight per day every 8 h for 5 days beginning at 48 h post-virus exposure. An increase in mean day to death, lessened decline in arterial oxygen saturation, and reduced lung consolidation and lung virus titers occurred in the treated animals. To determine the influence of viral challenge, experiments were run in which mice were infected with a 100 or 75% lethal dose of virus and were treated intravenously once daily for 5 days beginning 96 h after virus exposure. Weak inhibition of the mortality rate was seen in mice receiving the high viral challenge, whereas significant inhibition occurred in the animals infected with the lower viral challenge, indicating that MnSOD effects are virus dose dependent. To determine if treatment with small-particle aerosol would render an antiviral effect, infected mice were treated by this route for 1 h daily for 5 days beginning 72 h after virus exposure. A dose-responsive disease inhibition was seen. An infection induced by influenza B/Hong Kong/5/72 virus in mice was mildly inhibited by intravenous MnSOD treatment as seen by increased mean day to death, lessened arterial oxygen saturation decline, and lowered lung consolidation. MnSOD was well tolerated in all experiments. A combination of MnSOD and ribavirin, each administered with small-particle aerosol, resulted in a generally mild improvement of the disease induced by the influenza A virus compared with use of either material alone.

Severe combined immunodeficient (SCID) mice were found to be highly susceptible to murine cytomegalovirus (MCMV) infection. Treatment of infected mice with ganciclovir (12.5, 25, and 50 mg/kg of body weight for 10 days) starting 24 h after virus challenge resulted in delays in death by 2 to 8 days, and no animals survived the infection. (S)-1-[3-Hydroxy-2-(phosphonylmethoxy)propyl]cytosine (HPMPC) was much more potent, with doses of 1, 3.2, and 10 mg/kg/day (for 10 days) increasing the mean survival time by 15 to 30 days. Twenty-day treatments with HPMPC starting 5 days after virus inoculation increased the mean survival time by 24 to 32 days, with once-weekly (50-mg/kg) treatments being equivalent to daily (10-mg/kg) treatments. Delays in the development of liver, lung, and spleen virus titers in ganciclovir- and HPMPC-treated groups correlated with extensions in the mean survival times relative to the survival times of the placebo controls. The two compounds were approximately equally toxic to uninfected BALB/c mice treated for 10 days, causing 80 to 100% mortality after a dose of 150 mg/kg and 0% mortality after a dose of 75 mg/kg. Thus, the relative therapeutic index of HPMPC was 50-fold greater than that of ganciclovir. Recombinant alpha interferon delta 4 alpha 1/alpha 2 (1 x 10(4) and 5 x 10(4) units per mouse per day) and bropirimine (100 and 300 mg/kg/day) provided no protection from the lethal MCMV infection. The severe combined immunodeficient mouse MCMV infection is an important new model that will permit chemotherapy regimens to be studied over several months.

UV irradiation has been shown to activate the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in cell culture; however, only limited studies have been described in vivo. UV light has been categorized as UV-A (400 to 315 nm), -B (315 to 280 nm), or -C (less than 280 nm); the longer wavelengths are less harmful but more penetrative. Highly penetrative UV-A radiation constitutes the vast majority of UV sunlight reaching the earth's surface but is normally harmless. UV-B irradiation is more harmful but less prevalent than UV-A. In this report, the HIV-1 LTR-luciferase gene in the skin of transgenic mice was markedly activated when exposed to UV-B irradiation. The LTR in the skin of transgenic mice pretreated topically with a photosensitizing agent (psoralen) was also activated to similar levels when exposed to UV-A light. A 2-h exposure to sunlight activated the LTR in skin treated with psoralen, whereas the LTR in skin not treated with psoralen was activated after 7 h of sunlight exposure. The HIV-1 LTR-beta-galactosidase reporter gene was preferentially activated by UV-B irradiation in a small population of epidermal cells. The transgenic mouse models carrying HIV-1 LTR-luciferase and LTR-beta-galactosidase reporter genes have been used to demonstrate the in vivo UV-induced activation of the LTR and might be used to evaluate other environmental factors or pharmacologic substances that might potentially activate the HIV-1 LTR in vivo.

A protein antigen from an Eimeria protozoan has recently been reported to induce antitumor activity in mice. This activity most likely results from the strong induction of interkeukin-12 (IL-12) and gamma interferon (IFN-γ), which are also essential factors in the establishment of protective immunity against viral infection. We evaluated recombinant Eimeria antigen (rEA) as a potential immunotherapeutic agent in mouse and hamster models of acute phleboviral disease. Punta Toro virus (PTV) was highly sensitive to a single dose of nanogram quantities of rEA in the mouse infection model. Intraperitoneal treatment with rEA also reduced virus load and liver damage associated with PTV infection. IL-12 was elicited following exposure of uninfected mice to quantities of rEA of 10 ng or greater, and the levels peaked at between 3 and 8 h postexposure. IFN-γ release was induced more slowly and required less rEA (1 ng) to produce a significant rise in systemic levels. The induction of IL-12 and IFN-γ involved in the coordination of innate and adaptive immune responses to microbial pathogens required myeloid differentiation factor 88, a signaling adaptor shared by most members of the Toll-like receptor (TLR) family. Despite encouraging results in the murine system, rEA failed to protect hamsters challenged with PTV. Our findings suggest that hamsters may lack functional TLR11, which has recently been shown to recognize a profilin-like protein homologous to rEA from the protozoan Toxoplasma gondii . Further investigation into the immunostimulatory capacity of rEA in other mammalian systems is necessary.

The cyclopentane influenza virus neuraminidase inhibitor RWJ-270201 was evaluated against influenza A/NWS/33 (H1N1), A/Shangdong/09/93 (H3N2), A/Victoria/3/75 (H3N2), and B/Hong Kong/05/72 virus infections in mice. Treatment was by oral gavage twice daily for 5 days beginning 4 h pre-virus exposure. The influenza virus inhibitor oseltamivir was run in parallel, and ribavirin was included in studies with the A/Shangdong and B/Hong Kong viruses. RWJ-270201 was inhibitory to all infections using doses as low as 1 mg/kg/day. Oseltamivir was generally up to 10-fold less effective than RWJ-270201. Ribavirin was also inhibitory but was less tolerated by the mice at the 75-mg/kg/day dose used. Disease-inhibitory effects included prevention of death, lessening of decline of arterial oxygen saturation, inhibition of lung consolidation, and reduction in lung virus titers. RWJ-270201 and oseltamivir, at doses of 10 and 1 mg/kg/day each, were compared with regard to their effects on daily lung parameters in influenza A/Shangdong/09/93 virus-infected mice. Maximum virus titer inhibition was seen on day 1, with RWJ-270201 exhibiting the greater inhibitory effect, a titer reduction of >10 4 cell culture 50% infective doses (CCID 50 )/g. By day 8, the lung virus titers in mice treated with RWJ-270201 had declined to 10 1.2 CCID 50 /g, whereas titers from oseltamivir-treated animals were >10 3 CCID 50 /g. Mean lung consolidation was also higher in the oseltamivir-treated animals on day 8. Both neuraminidase inhibitors were well tolerated by the mice. RWJ-270201 was nontoxic at doses as high as 1,000 mg/kg/day. These data indicate potential for the oral use of RWJ-270201 in the treatment of influenza virus infections in humans.

Cidofovir is the first nucleoside monophosphate analogue currently being used for the treatment of human cytomegalovirus (HCMV) retinitis in individuals with AIDS. Unfortunately, the period of therapy with the use of this compound may be limited due to the possible emergence of serious irreversible nephrotoxic effects. New drugs with improved toxicity profiles are needed. The goal of this study was to investigate the anticytomegaloviral properties and drug-induced toxicity of a novel phosphonate analogue, namely, (−)-2-( R )-dihydroxyphosphinoyl-5-( S )-(guanin-9′-yl-methyl) tetrahydrofuran (compound 1), in comparison with those of cidofovir. The inhibitory activities of both compounds on HCMV propagation in vitro were similar against the AD 169 and Towne strains, with 50% inhibitory concentrations ranging from 0.02 to 0.17 μg/ml for cidofovir and P < 0.001) with a drug regimen of 10 mg/kg/day.

A series of twelve recently synthesized 6-substituted derivatives of 9-β- d -ribofuranosylpurine 3′,5′-cyclic phosphate (RPcMP) were evaluated for in vitro antiviral activity, using inhibition of viral cytopathogenic effect as the primary parameter for evaluation. Inhibition of the development of intra- and extracellular virus titer was used as a secondary criterion with certain viruses. Five derivatives were considered to have significant antiviral activity. 6-Hydroxylamino-RPcMP was active against type 1 herpes simplex, cytomegalo-, and vaccinia viruses. 6-Thio-RPcMP was inhibitory to types 1 and 2 herpes simplex, cytomegalo-, vaccinia, and type 3 parainfluenza viruses. The 6-methylthio derivative was active against types 1 and 2 herpes simplex, cytomegalo-, and vaccinia viruses, and types 1A, 2, 8, and 13 rhinoviruses; alteration of this 6-substitution to 6-ethylthio or to 6-benzylthio weakened the herpes- and vaccinia virus activity of the compound, but each continued to have significant antirhinovirus activity. The effect of time of addition of 6-methylthio-RPcMP to type 1 herpes simplex virus-infected cells was determined; the compound was most active when added prior to the virus. Early removal of the compound from the infected cells markedly reduced its antiviral effectiveness.

Equine abortion virus (EAV)-induced hepatitis in hamsters presents an interesting animal model for the evaluation of drugs possessing anti-deoxyribonucleic acid virus activity. These experiments demonstrate that 9-β- d -arabinofuranosylhypoxanthine 5′-monophosphate (ara-HxMP), a new synthetic, water-soluble, antiviral agent, effectively controls this disease in hamsters with a therapeutic index of ∼60. Ara-HxMP prevented hepatitis-associated deaths in hamsters, reduced the titer of EAV developing in hamsters, and inhibited the increase of serum glutamic pyruvic transaminase in EAV-infected hamsters.

Topical application of 9-β- d -arabinofuranosylhypoxanthine 5′-monophosphate (ara-HxMP) significantly inhibited the development of keratitis induced by types 1 and 2 herpes simplex virus and vaccinia virus in the eyes of rabbits. Parameters for evaluation of efficacy were infectivity (corneal opacity, lesion size, and type), Draize (erythema, conjunctival swelling, and discharge), and reduction in titer of recoverable virus from the eye. When the relative efficacy of the related compounds 9-β- d -arabinofuranosyladenine (ara-A), ara-A 5′-monophosphate (ara-AMP), and ara-Hx was determined against type 1 herpes simplex virus in a parallel experiment, the more water-soluble compounds (ara-HxMP, ara-AMP) were the most effective. The relative efficacy of ara-A was also determined against type 2 herpes and vaccinia virus-induced keratitis. Mortality in rabbits due to central nervous system involvement caused by types 1 and 2 herpes simplex virus was inhibited. Ara-HxMP was not discernibly toxic to the eye at concentrations of at least 20%; efficacy was still discernible with a 0.1% solution.

9-β- d -Arabinofuranosylhypoxanthine 5′-monophosphate (ara-HxMP) significantly controlled the development of encephalitis produced by deoxyribonucleic acid viruses in mice. In most experiments the activities of ara-HxMP and 9-β- d -arabinofuranosyladenine (ara-A) were determined simultaneously. In the intracerebral (target organ) and intravenous therapy experiments, ara-HxMP had a pronounced advantage over ara-A since the water solubility of ara-HxMP enabled it to be used in much higher concentrations. In experiments where the two drugs were administered intraperitoneally or orally they exhibited similar activity. In several intraperitoneal therapy experiments ara-HxMP was tested alone, using various treatment schedules and dosages. In these experiments, efficacy was observed in groups that had treatments initiated as late as 72 h after virus inoculation.

The effects of four ribonucleic acid virus inhibitors were evaluated in cell cultures and in mice to determine inhibitory effects against bluetongue virus and Colorado tick fever virus (CTFV). Test compounds included 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin), 3-deazaguanine, 3-deazauridine, and 9-(S)-(2,3-dihydroxypropyl)adenine. Ribavirin-2',3',5'-triacetate (ribavirin triacetate) was evaluated in vivo against CTFV. Inhibition of cytopathic effect and plaque reduction were used to evaluate antiviral activity. In cytopathic effect inhibition studies, bluetongue virus was markedly inhibited by 3-deazaguanine and 3-deazauridine in Vero cells with moderate inhibition by the other agents. Ribavirin and 3-deazaguanine markedly inhibited CTFV in MA-104 cells, 3-deazauridine was slightly less active, and 9-(S)-(2,3-dihydroxypropyl)adenine was negative. Ribavirin was less effective in Vero cells against CTFV. When mice were inoculated intracerebrally with CTFV and treated by a single intracerebral injection with drug, ribavirin triacetate increased the number of survivors, 3-deazaguanine increased mean survival time, and ribavirin was negative. Intraperitoneal treatment of infected mice with ribavirin triacetate for 1 week significantly increased the number of survivors and mean survival time, providing strong evidence that the agent is active across the blood-brain barrier.

A sensitive in vivo system was studied for use in evaluating relatively small quantities of antiviral compounds. Swiss mice were injected intracerebrally with 10 LD 50 of type 1 herpes simplex virus (HSV) or vaccinia virus. Test compounds were injected intracerebrally into mice at a standard time interval after virus inoculation. Significant increases in the number of survivors in drug-treated, infected animals as compared to saline-treated virus controls was the criterion for evaluation of antiviral activity. 9-β- d -Arabinofuranosyladenine (Ara-A) was used to determine an optimal time of therapy for this system. Significant survival increases occurred when the drug was injected 3, 6, 12, and 48 hr after HSV inoculation, with maximal effect occurring after the 6-hr treatment interval. Determination of brain virus titer of 6-hr Ara-A- and saline-treated mice at various intervals indicated that treatment with the drug delayed development of detectable levels of HSV by 1 day. 1-β- d -Arabinofuranosylcytosine (Ara-C), trifluorothymidine (TFT), and 5-iodo-2′-deoxyuridine (IDU) were also evaluated with the use of the 6-hr treatment time against HSV and vaccinia virus. Ara-A and TFT increased the number of survivors among mice infected with either virus, whereas Ara-C increased the survivors among HSV-infected, but not vaccinia virus-infected, mice. IDU was inactive against both viruses.

Virazole (1-β- d -ribofuranosyl-1,2,4-triazole-3-carboxamide) is a highly soluble new synthetic nucleoside having significant, reproducible activity against a broad spectrum of deoxyribonucleic acid and ribonucleic acid viruses in vitro. The drug inhibited viral cytopathogenic effects in monolayers of cells infected for 3 days with type 3 adeno, types 1 and 2 herpes, myxoma, cytomegalo, vaccinia, infectious bovine rhinotracheitis, types 1A, 2, 8, 13, and 56 rhino, types 1 and 3 parainfluenza, vesicular stomatitis, subacute sclerosing panencephalitis, Semliki Forest, Newcastle disease, and measles viruses. Hemagglutinin production by influenza A 2 , influenza B, and type 1 parainfluenza viruses in chicken embryo cells was reduced by Virazole treatment. Recoverable intra- and extracellular virus titers were reduced by the drug in experiments with type 1 herpes, vaccinia, type 3 parainfluenza, and vesicular stomatitis viruses. Plaque formation by type 1 herpesvirus was also inhibited by exposure of the infected cells to Virazole. Pretreatment of cells with the compound, followed by its removal before addition of type 1 herpesvirus, severely lessened the antiviral activity; the compound was still moderately effective in reducing the viral effects on the cells when added as long as 22 hr after the virus. Parallel experiments, in which the antiviral activity of a number of known active drugs was compared, indicated Virazole to have at least a comparable degree of activity, and it was also active against a wider variety of viruses than any of these known active materials. The CCED 50 of Virazole to chicken embryo cells was approximately 1,000 μg/ml, although concentrations as low as 10 μg/ml caused slight (15%) inhibition in total cellular protein after 72 hr of incubation.

A quantitative, reproducible method was developed for the evaluation of the virucidal activity of test gases. Using this method, we determined the virucidal effectiveness of a Steri-Vac ethylene oxide gas sterilizer. Wool gabardine material was exposed to high concentrations of herpes simplex, vaccinia, parainfluenza, or polio viruses and was processed through the sterilizer. Two time-temperature cycles of the machine, 29 C for 180 min and 60 C for 48 min, were used in separate experiments. The viruses were exposed to the gas when freshly pipetted onto the fabric or when pipetted on the material and allowed to dry 16 to 24 hr. In two experiments carried out under each condition, the virus titers were reduced by the sterilization process to less than detectable limits. These titer reductions were for the herpes virus ≥ 2.7 to 5.0 log, for vaccinia virus ≥ 4.0 to 6.1 log, for parainfluenza virus ≥ 1.8 to 4.9 log, and for poliovirus ≥ 4.9 to 7.7 log. The observed reductions in virus titers were the same whether the virus-contaminated fabrics were sealed in polyethylene packages or held in open petri dishes during exposure to ethylene oxide.

Topical application of 1-β- d -ribofuranosyl-1,2,4-triazole-3-carboxamide (Virazole) significantly inhibited the development of herpetic keratitis in the eyes of rabbits, as determined by both infectivity and Draize scoring parameters. Significant inhibition of the infection was demonstrated with 10% concentrations of Virazole; a 1% solution had a moderate effect, whereas doses of 0.1 and 0.01% had little activity in this system. A 5% concentration of Virazole similarly inhibited vaccinia keratitis in rabbits. Encephalitis-induced mortality in hamsters initially infected intraocularly with herpesvirus was significantly prevented or inhibited by topical application of 5, 10, and 20% concentrations of Virazole. Surviving, treated hamsters had no signs of herpes keratitis. The 20% concentration was the approximate LD 50 in hamsters. Virazole administered subcutaneously or intraperitoneally to mice did not appreciably alter the course of herpes virus- or vaccinia virus-induced encephalitis in these animals, although in a herpesvirus experiment direct injection of the drug into the brains 3 hr prior to virus inoculation resulted in a significant survivor increase.

The persistence of vaccinia virus on wool (blanket and gabardine) and cotton (sheeting, terry cloth, and knit jersey) fabrics was studied. The fabrics were exposed to the virus by three methods: direct contact, aerosol, and virus-containing dust having a high content of textile fibers. Fabrics exposed to virus by each method were held in 35 and 78% relative humidities at 25 C. Virus was recovered for up to 14 weeks from wool fabrics exposed to virus and held in the low humidity. In contrast, virus persisted for shorter periods of time on the cotton fabrics. No virus was detected on terry cloth as early as 3 days after exposure to virus. The virus appeared to be less stable in the high humidity, and the method of exposure of the fabrics to virus apparently had an effect upon the persistence of the agent. On all fabrics, viral persistence was of sufficient duration to be of epidemiological significance.

Eight compounds were tested in vitro for virucidal and antiviral activity against poliovirus and vaccinia virus. These compounds included five quaternary ammonium salts, two bromosalicylanilides, and neomycin sulfate, an antibiotic. None of the compounds was active against poliovirus, but virucidal activity was demonstrated against vaccinia virus with three of the quarternary ammonium compounds: n -alkyl (C14, C12, C16) dimethyl benzyl ammonium chloride, di-isobutyl cresoxy ethoxy ethyl dimethyl benzyl ammonium chloride monohydrate, and n -alkyl (60% C14, 30% C16, 5% C12, 5% C18) dimethyl benzyl ammonium chlorides plus n -alkyl (50% C12, 30% C14, 17% C16, 3% C18) dimethyl ethylbenzyl ammonium chlorides. Wool blanketing, wool gabardine, and cotton sheeting materials were impregnated with the first of the above virucidal compounds, and the persistence of vaccinia virus on these fabrics was compared with the persistence of the agent on nonimpregnated fabrics of the same type held at 25 C in 35 and 78% relative humidity. No virus could be recovered from the chemically treated fabrics at any time after virus exposure, whereas the virus persisted as long as 4 weeks on nonimpregnated materials. Viable vaccinia virus was also found to persist less than 1 day on a cotton fabric finished with a wash-and-wear modified triazone resin. Poliovirus persisted less than 5 days on this wash-and-wear fabric.

The in vivo anti-influenza virus and antivaccinia virus activity of 156 biologically active compounds was determined. One of two criteria was used for evaluating activity against the influenza virus. The criteria were increase in survivor number and mean survival time, and reduction in virus-induced lung consolidation in treated, infected Swiss mice. Increase in survivor number and mean survival time were the criteria for evaluation of antivaccinia virus activity. Several drug doses were tested against two virus concentrations to demonstrate antiviral activity more clearly. Two compounds were considered significantly active against the influenza virus: DL-noformicin (NSC 72942) and amantadine hydrochloride (NSC 83653). Eleven compounds had reproducible activity against vaccinia virus: isatin-β-thiosemicarbazone (NSC 721), 6-azauracil (NSC 3425), 9-α-fluoro-2α-methylhydrocortisone 21-acetate (NSC 12601), 5-[bis(2-chloroethyl)amino]uracil (NSC 34462), 5-iodo-2′-deoxyuridine (NSC 39661), streptonigrin (NSC 45383), N -methylisatin β-thiosemicarbazone (NSC 69811), cytovirin (NSC 91770), 9-β-D-arabinofuranosyladenine (NSC 404241), and 5-(mercaptomethyl)uracil (NSC 529351).

In cultured cells, Virazole failed to stimulate either interferon or a cellular resistance which continued in its absence. Serum from Virazole-treated mice likewise contained no demonstrable interferon.