From: Supply and Services Canada R&D Bulletin - Science and Technology No. 234, September 1992 Better blood sterilization with ozone. Ozone may soon be used to destroy viruses in donated blood, thanks to researchers at the Department of National Defence (DND) and the Canadian Red Cross Society (CRCS). Under a $303.943 contract with the Surgeon General Branch of DND's National Defence Headquarters, researchers from the National Reference Laboratory at the CRCS are investigating two ozone sterilization technologies to confirm their reported efficacy in deactivating a variety of potential viral contaminants of blood, including HIV-1 and hepatitis. Many developing countries cannot afford blood-screening, which costs about $45 for each unit of blood and requires a trained technician. "If the Canadian military is operating in an underdeveloped part of the world and is cut off from its supplies, we may have to resort to local blood sources," says Major Brian Crowell, Health Services Research Coordinator at DND. "We're looking for a sterilization technique that can be taken to the field, put together on the tailboard of a truck or in a tent, and used to sterilize donated blood quickly and effectively." Once developed, such a sterilization technique would have applications beyond the military. Dr. Peter Gill, Director of the CRCS's National Reference Laboratory, says ozone sterilization technology could be used in disasters to aid civilian populations. Ozone gas is produced by passing electricity through pure oxygen. Although ozone is toxic when inhaled over time, at the right concentrations it is highly effective as an antimicrobial. Over 2,000 water-purification plants worldwide, including those in Moscow and Montreal, use ozone to decontaminate water. Researchers are investigating two methods of sterilizing blood with ozone that have been patented by Medizone (Canada) Inc. and Mueller Medical International Inc. One of these methods exposes 10 cm(3) of blood to heat (42.5 C) and ultraviolet light. Ozone gas is bubbled in through a tube. The blood foams up alongside the vial, exposing more blood surface area to the light, heat and ozone. Following treatment, the container is spun to force the blood down. The other method uses a hollow fibre system between the ozone and the blood. The membrane separates the blood from the ozone and oxygen. Over time, a pre-determined amount of ozone is absorbed into the blood. The amount of ozone absorbed is measured by subtracting the amount of ozone going back into the machine from the amount that left the machine. These ozone sterilization methods are easy to operate, quick to perform (from three to 60 minutes), and chap (no more than $15 for each unit of blood). Researchers will also investigate ways to combine ozone sterilization and filtration technologies. Filtering the blood to reduce the number of white cells, the site of most intra- cellular viral infections, means viruses can be deactivated using low levels of ozone. This is preferable to using high levels of ozone, which could change the molecular structure of the blood. For example, the haemoglobin structure may be altered so that it no longer acts as an oxygen carrier. At low doses, however, there are no known adverse or toxic side effects of ozone sterilization. In Europe, an estimated 350,000 people were treated with ozone between 1980 and 1985. The university of Bonn reviewed these cases in 1986 and reported virtually no side effects of ozone therapy when properly administered. Test results so far indicate that even low concentrations of ozone are extremely effective at deactivating extra-sterilized 10 cm(3) of blood containing enough HIV to infect the entire world population 10 times. Results from Bethesda Naval Hospital in Bethesda, Maryland, indicate that ozone can also be effective against intra-cellular viruses when used in higher concentrations. The ozone seems to destroy only infected cells, exposing the viral material to the gas and ultimately deactivating the virus, all without creating toxicity problems. HIV research using similar technologies may lead to an "autovaccine" for AIDS patients in which a patient's blood would be treated with ozone and re-introduced. A cure would be unlikely, but the autovaccine may be able to control the infection by boosting the immune system, suppressing virus replication, and re-introducing deactivated samples of all mutant forms of the HIV-1 virus. Researchers hope that ozone sterilization for blood fractionates such as Factor VIII, a clotting agent given to haemophiliacs, will be available soon. Technologies for sterilizing whole blood may be on the market in a few years. Ozone sterilization technologies may be approved only for emergency blood supplies at first, but if evidence is found that some viruses are not being screened, the treatment may be extended to all blood collections. "The products of this research have worldwide applications," says DND's Capt. (N) Shannon. "In the right concentration, ozone sounds almost too good to be true. We're trying not to be overly enthusiastic, but the data so far is very compelling."