Various antimicrobial factors present in human milk were tested for in-vitro antiviral activity against three rhinoviruses (two clinical isolates and rhinovirus 2) and an isolate of cytomegalovirus (CMV) from human milk. These factors included the gangliosides GM1, 2 and 3, sialyl-lactose, chondroitin sulphates A, B and C, prostaglandins E2 and F2alpha, monolaurin, vitamin A and the protein lactoferrin. All were tested for their ability to inhibit growth of the viruses in cell culture. Human milk was also tested for antiviral activity against these viruses. Only vitamin A, monolaurin and lactoferrin inhibited the growth of CMV, whereas both prostaglandins enhanced the growth of this virus at least four-fold. CMV infects infants from milk but, nevertheless, the milk-borne CMV isolate showed no special resistance to any of the antiviral factors tested. None of the compounds inhibited or enhanced the growth of the rhinoviruses. However, human milk decreased the growth of some of the rhinoviruses and specific secretory immunoglobulin A (sIgA) neutralised the virus.

Latent viral reactivation is a commonly reported manifestation of immune system dysregulation during spaceflight. As physical fitness and exercise training have been shown to benefit multiple arms of the immune system, we hypothesized that higher levels of preflight physical fitness and/or maintaining fitness during a mission would protect astronauts from latent viral reactivation. Standardized tests of maximal strength, muscular endurance, flexibility, and cardiorespiratory fitness (CRF) were performed in 22 international space station (ISS) crewmembers before and after a ~6-month mission. Reactivation of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and varicella zoster virus (VZV) was determined in crewmembers and ground-based controls before, during, and after spaceflight. Crewmembers with higher CRF before spaceflight had a 29% reduced risk of latent viral reactivation compared to crew with lower CRF. Higher preflight upper body muscular endurance was associated with a 39% reduced risk of viral reactivation, a longer time to viral reactivation, and lower peak viral DNA concentrations, particularly for EBV and VZV. Latent viral reactivation rates were highest in crew with lower preflight CRF and higher levels of CRF deconditioning on return to Earth. We conclude that physical fitness may protect astronauts from latent viral reactivation during long duration spaceflight missions.

Suspensions of herpes simplex virus types 1 and 2, cytomegalovirus, and parainfluenzavirus type 2 were inactivated within 24 h when treated at 37 degrees C with 1 mg (5.05 mM) of copper-catalyzed sodium ascorbate per ml. The infectivity titer of respiratory syncytial virus was reduced substantially after 24 h but required 48 h for inactivation. Under these conditions, inactivation of these viruses was also successfully achieved with 5.68 mM catalyzed ascorbic acid. Copper (Cu2+), when added with the ascorbate solution at 5 micrograms/ml (0.022 mM), exhibited a catalytic effect on the inactivation of these viruses. The rate of inactivation was affected by the incubation temperature, time of exposure, and the virus concentration. Ascorbate concentrations as high as 10 mg/ml (50.5 mM) demonstrated only a minimum increase in effect on viral inactivation. The loss of infectivity did not alter either the hemagglutination or complement fixation qualities of the antigens.

A cytopathic 'stealth' virus was cultured from the cerebrospinal fluid of a patient with a bipolar psychotic disorder who developed a severe encephalopathy leading to a vegetative state. DNA sequencing of a polymerase chain reaction-amplified product from infected cultures has identified the virus as an African green monkey simian cytomegalovirus (SCMV)-related stealth virus. The virus is similar to the SCMV-related stealth virus isolated from a patient with chronic fatigue syndrome. The findings support the concepts that stealth viruses can account for a spectrum of dysfunctional brain diseases and that some of these viruses may have arisen from live polio viral vaccines.