Cupric and ferric ions were able to inactivate five enveloped or nonenveloped, singleor double-stranded DNA or RNA viruses. The virucidal effect of these metals was enhanced by the addition of peroxide, particularly for copper(II). Under the conditions of our test, mixtures of copper(II) ions and peroxide were more efficient than glutaraldehyde in inactivating 4X174, T7, +6, Junin, and herpes simplex viruses. The substances described here should be able to inactivate most, if not all, viruses that have been found contaminating medical devices.

The inactivation of herpes simplex virus (HSV) by copper was enhanced by the following reducing agents at the indicated relative level: ascorbic acid > hydrogen peroxide > cysteine. Treatment of HSV-infected cells with combinations of Cu(II) and ascorbate completely inhibited virus plaque formation to below 0.006% of the infectious virus input, while it maintained 30% viability for the host mammalian cells. The logarithm of the surviving fraction of HSV mediated by 1 mg of Cu(II) per liter and 100 mg of reducing agent per liter followed a linear relationship with the reaction time, in which the kinetic rate constant for each reducing agent was -0.87 min(-1) (r = 0.93) for ascorbate, -0.10 min(-1) (r = 0.97) for hydrogen peroxide, and -0.04 min(-1) (r = 0.97) for cysteine. The protective effects of metal chelators and catalase, the lack of effect of superoxide dismutase, and the partial protection conferred by free-radical scavengers suggest that the mechanism of copper-mediated HSV inactivation is similar to that previously reported for copper-mediated DNA damage. The sensitivity exhibited by HSV to Cu(II) and reducing agents, particularly ascorbate, might be useful in the development of therapeutic antiviral agents.

Few condoms allowed any virus penetration. The median amount of penetration for latex condoms when extrapolated to expected actual use conditions was 1 x 10(-5) ml (volume of semen). Thus, even for the few condoms that do allow virus penetration, the typical level of exposure to semen would be several orders of magnitude lower than for no condom at all.

Viruses are used to test the barrier properties of materials. Binding of virus particles during passage through holes in the material may yield misleading test results. The choices of challenge virus and suspending medium may be important for minimizing confounding effects that might arise from such binding. In this study, different surrogate viruses, as well as different support media, were evaluated to determine optimal test parameters. Two membranes with high-binding properties (nitrocellulose and cationic polysulfone) were used as filters to compare binding activities of different surrogate challenge viruses (MS2, X174, T7, PRD1, and 6) in different media. The media consisted of buffered saline with surfactants, serum, or culture broth as additives. In addition, elution rates of viruses that bound to the membranes were determined. The results suggest that viruses can bind by hydrophobic and electrostatic interactions, with X174 displaying the lowest level of binding by either process. The nonionic detergents Triton X-100 and Tween 80 (0.1%) equally minimized hydrophobic interactions. Neither anionic nor cationic surfactants were as effective at nontoxic levels. Serum was effective at reducing both hydrophobic and electrostatic binding, with 2% being sufficient for eliminating binding under our test conditions. Thus, X174 remains the best choice as a surrogate virus to test barrier materials, and Triton X-100 (0.1%) remains a good choice for reducing hydrophobic binding. In addition, binding of viruses by barrier materials is unlikely to prevent passage of blood-borne pathogens.

This study evaluated bacteriophages 1)X174, T7, PRD1, and 4)6 as possible surrogates for pathogenic human viruses to challenge barrier materials and demonstrated some important factors for their use. Chemical incompatibility with test material was demonstrated when lipid-enveloped 1)6 was inactivated by an aqueous eluate of vinyl gloves, but 0.5% calf serum protected (D6 from the eluate. Low concentrations (2%) of calf serum also prevented the exaggerated binding of the bacteriophages to filters. Recovery of viruses from surfaces decreased with increasing time before recovery. Penetration through punctures displayed different types of kinetics. The combined data indicate that (i) some bacteriophages may serve as surrogate viruses, (ii) experimental conditions determine whether a particular virus is appropriate as a challenge, and (iii) 1)X174 is an excellent choice as a surrogate virus to test barrier materials. The data further indicate that before barrier materials are challenged with viruses, adequate tests should be performed to ensure that the virus is compatible with the test material and test conditions, so that meaningful data will result.

Does the 1000 mL water leak test for medical gloves detect potential for virus penetration? Water leak and virus penetration were determined sequentially in hanging latex surgical gloves (4 brands) with 1000 ml of ΦX174-containing buffered saline (DPBS). Individual fingers (some punctured) were visually examined for water (DPBS) leaks for 2 minutes, then dipped into DPBS for 60 minutes for collection of virus that penetrated the latex barrier. Many punctured and a few non-punctured fingers leaked both water and virus. Some punctured fingers did not leak water nor virus. A few of the control and punctured fingers that did not leak water did allow very low-level virus penetration by 1 hour; 4–50 fold lower than virus penetration from barely-detectable water leaks. Thus, a few gloves with potential for very low-level virus penetration were not detected by the 1000 mL water leak test.

A method by which virus penetration through condoms can be tested with simple, inexpensive equipment is described. The method uses chi X174 bacteriophage as the challenge virus and physiologically relevant pressure. Penetration by 0.1 microliters (or less) of challenge suspension can be readily detected. As examples, latex and natural-membrane condoms were examined.

Barrier integrity of unaged and oven-aged (at 70 degrees C) natural rubber latex examination gloves was assessed with a biaxial flex-fatigue method where failure was detected electronically, and by live viral penetration testing performed according to a modified version of ASTM F1671-97a. When no change in barrier properties was detected during flex testing, no virus passage was found after viral challenge. Conversely, when a change in the barrier properties was indicated by the electrical signal, virus passage was found in 74% of the specimens. Flex-fatigue results indicated that unaged test specimens from powdered (PD) and powder-free (PF) nonchlorinated gloves had significantly longer fatigue lives than powder-free chlorinated (CL) gloves from the same manufacturer. Biaxial flexing of oven-aged glove specimens showed a marginal increase in fatigue life for the PF gloves, but no increase for the PD gloves. The fatigue life of the CL gloves was observed to increase significantly after oven aging. However, this appears to be due to a design feature of the test apparatus, wherein peak volume displacement of the worked specimen is held constant. An aging-induced change in the viscoelastic properties of the CL gloves-permanent deformation of the specimens early in the fatigue test-relieves the stress magnitude applied as the test progresses. Thus, permanent deformation acts as a confounding factor in measuring durability of latex gloves by fixed displacement flex-fatigue.