Germicides

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=90 BGCOLOR="#CCFF99" TEXT="#080000" bgproperties="fixed" background="04078671esnimw.png"> <div> <FONT SIZE="5" COLOR="#CCFF99" FACE="Arial" ><B>AVIANITARIAN Reference Guide </B></FONT><B>     |     </B><A HREF="index_avianitarian.htm" TARGET="_top" TITLE="AVIANITARIAN Reference Guide "><B>home</B></A></div> <div> <A HREF="id191.htm" TARGET="_top" TITLE="Contributors">Contributors</A>   |   <A HREF="id190.htm" TARGET="_top" TITLE="From the Author">From the Author</A>   |   <A HREF="home.htm" TARGET="_top" TITLE="Aviculture Microbiology">Aviculture Microbiology</A>   |   <A HREF="id166.htm" TARGET="_top" TITLE="DISCLAIMER">DISCLAIMER</A>   |   <A HREF="id48.htm" TARGET="_top" TITLE="Index to workbook">Index to workbook</A>   |   <A HREF="id155.htm" TARGET="_top" TITLE="Colleagues">Colleagues</A>   |   <A HREF="id154.htm" TARGET="_top" TITLE="Avianitarian Assessment">Avianitarian  Assessment</A>   |   <A HREF="id123.htm" TARGET="_top" TITLE="Sanitation and Sterilization">Sanitation and Sterilization</A>   |   <A HREF="id124.htm" TARGET="_top" TITLE="Sterilization">Sterilization</A>   |   <A HREF="id159.htm" TARGET="_top" TITLE="Specific Types of Disinfectants">Specific Types of Disinfectants</A>   |   <B>Germicides</B>   |   <A HREF="id126.htm" TARGET="_top" TITLE="Environmental Issues">Environmental Issues</A>   |   <A HREF="id171.htm" TARGET="_top" TITLE="Puzzle">Puzzle</A>   |   <A HREF="id187.htm" TARGET="_top" TITLE="new puzzle">new puzzle</A></div> <div> </div> </td> </tr><tr> <td valign="top" width=200 BGCOLOR="#336699" TEXT="#080000" bgproperties="fixed" background="041c83b3.png"> <div> Jim is a breeder of lories, Africans and Pyrrhura. conures in Victoria BC.</div> <div> He is actively involved with the local bird club, the Aviculture Advancement Council of Canada, and the Canadian Parrot Symposium West</div> <div> Jim has been breeding birds for ten years.</div> <bR> <bR> </td> <td valign="top" height=390 width="100%" BGCOLOR="#CCFF99" TEXT="#080000"> <div> <I>Germicides</I></div> <DIV ALIGN="LEFT"></DIV> <div> <B>GERMICIDES</B></div> <div> <B>Copyright reserved by </B></div> <div> <B>James B. Taylor M.A.Sc. PEng.</B></div> <bR> <div> <B><U>Introduction</U></B></div> <bR> <div>      Ever since the germ theory of disease became widely accepted, chemists have been developing agents to kill these germs. Many chemicals will easily kill microorganisms but may not be useful for many reasons. They may be too toxic, corrosive, unstable, or expensive to be used as a germ killer. There are hundreds that have been used for this purpose but there is not one universal chemical that can be used in all applications against all infectious agents. As the list is very long, this report will focus on the agents used in a commercial aviary - a captive bird breeding facility.  The agents that can be used in such a facility are limited by the nature of birds. Birds are much more susceptible to air born chemical agents than humans. Their respiratory system is twice as efficient as a mammal's, thus; it will absorb chemicals from the air much more efficiently. Most birds have not been bred in captivity for a long enough time to develop resistance to many common chemical agents or infectious agents associated with man. Therefore, the use of these of chemicals is quite important but the particular chemical and method of application is much more important.</div> <bR> <div> <B><U>Definitions</U></B></div> <bR> <div>      Many terms have been applied to germ killers/disinfectants in the literature and in common usage. There is a consensus concerning a few of these terms but many are open to interpretation. In this report, the following definitions are used for clarity though many would disagree with their rigor.</div> <bR> <bR> <div> Antiseptic: A substance used on skin that inhibits the growth and development of microorganisms but does not necessarily kill them. </div> <bR> <div> Biocide: A chemical that kills microorganisms and can be synthetic or naturally occurring. A biocide can be a bactericide and/or a fungicide and/or a viricide depending on which type of microorganism(s) it acts on.</div> <bR> <div> Biostatic: The inhibition of growth of microorganisms to prevent further contamination but the word does not necessarily imply that the organism is killed. An agent can be bacteriostatic and/or fungistatic and/or viristatic depending on which type of microorganism(s) it acts upon.</div> <bR> <div> Disinfection: The destruction of most harmful microorganisms on inanimate objects especially the vegetative forms but not necessarily their spores.</div> <div>      </div> <div> Sanitize: The use of an agent to reduce the number of microbial contaminants to a safe level as determined by public health requirements.</div> <bR> <div>      Sterilization: The destruction of all-living microorganisms and is an absolute condition.</div> <bR> <div> Germicide or Agent: General terms which will be used to refer to any or all of the above. </div> <div> <B><U>Pathogens</U></B></div> <bR> <div>      The organisms that cause disease -pathogens - belong to a number of classes: bacteria, fungi, viruses, and parasites. </div> <div> Bacteria are single cell organisms with a rigid cell wall and a fluid interior. Bacteria are found as either a vegetative cell or an endospore. When food and environmental conditions are right for growth, bacteria as vegetative cells reproduce by cell division. Bacteria are the most sensitive to germicides in this state. If food is scarce sporulation occurs and a bacterium forms an endospore. In this state the bacteria remain dormant and are very resistant to germicides. Endospores can remain dormant for years, centuries and in some case, millennia. When conditions are right the spore germinates rapidly back to the vegetative form and continues growth. For sterilization, both forms of the bacteria must be killed.</div> <div> Fungi are simple plants lacking roots, stems, leaves, and chlorophyll. They have rigid cell walls and true nuclei.</div> <div> A virus is a genetic element containing either DNA or RNA, which replicates inside cells but is characterized by having an extracellular state. There are two types of viruses, enveloped and unenveloped. Enveloped or lipophilic viruses are surrounded by a lipid (fatty) coating. They are generally less environmentally stable and more prone to attack by chemical agents. The unenveloped or hydrophilic viruses or caspid viruses have a protein outer coating and are generally more environmentally stable and more resistant to chemical action.</div> <div> Parasites can range from flagellates such as giardia and trichomonas to worms. Chemical agents are generally used to kill either the organism or it's eggs.</div> <bR> <bR> <bR> <div> <B><U>Physical and Chemical Factors</U></B></div> <bR> <div> There are a number of properties that must be considered when using or specifying a germicide. They include concentration, solvent, pH, ionic content, chemical activity, surface activity, and temperature.</div> <bR> <div> The concentration of a germicide in a solvent greatly affects how the agent will function. There is always some minimum concentration of the agent required to perform the particular job. At what concentration a germicide would be effective depends on a number of factors. The first factor is the action required of the germicide: biostatic action, biocidal action, or sterilant. The concentration of the agent will determine what will be the effect on microorganisms. At a low concentration, growth may be inhibited. At a higher concentration, the agent may kill most of the organisms. At a very high concentration total sterilization may occur. An example is a solution of chlorine gas in water. Some agents will only inhibit growth and may not kill at any concentration. </div> <div> The ability of a germicide to react with surfaces will decrease the effective concentration of the agent. This would require a larger concentration of the germicide to allow these losses and retain an effective germicidal concentration. A number of possible germicides are too low in solubility to attain a large enough concentration in solution to be of use. This is especially true with many phenolics. </div> <div>  </div> <div> The second factor is what the agent is to be used for. As an antiseptic, the concentration of a germicide may affect its skin toxicity. A dilute concentration might be tolerated whereas a concentrated solution may cause skin irritation or cell damage. The concentration of a disinfectant would determine how much damage or corrosion would be caused to the materials being disinfected. Many germicides may react with plastics and others may corrode metal surfaces depending on the concentration of the agent.</div> <div> A third factor is cost. Some germicides are very expensive and would not be used for general purpose cleaning. Some require expensive equipment for utilization. Examples would be the gasses such as chlorine for water purification or ethylene oxide, a very poisonous gas commonly used for sterilization.  </div> <div> Most germicides are used in solution. The solvent may be water but could be an alcohol or other organic chemical. Many solvents have germicidal action and increase the effectiveness of other agents when used as a solvent. An example would be tincture of iodine. The alcohol increases the effectiveness of the iodine. The solvent choice may facilitate the contact of the germicide with the microbe. Many solvents that can dissolve away protective coatings allowing access to the cell wall of a microorganism by the germicide. The choice of solvents must take in to consideration toxicity, corrosivity, volatility, and solvent effects on surfaces.</div> <bR> <div>      The pH of the germicidal solution may affect the ability of the agent to react with microbes. Extremes of pH are antimicrobial. Some germicides dissociate in solution and one particular species formed may be the effective agent. At extremes of pH, the effective species may not be present. An example would be a solution of chlorine in water. HOCl, found at low pH, is an effective germicide. At high pH the -OCl ion is 1/80 as effective as the HOCl species. To maintain an effective pH buffers can be used.</div> <bR> <div>      The other ionic species in a solution, along with the germicide, may change the effectiveness of the agent positively or negatively. Many salts inhibit micro growth by themselves and may enhance the action as long as their presence does not decrease the solubility of the germicide by salting out or common ion effect. Other salts may form complexes with germicides and decrease the effective concentration of the agent in solution. Surfactants in solution can have similar effects. The surfactant may increase the contact of the germicide with the microorganism but may also complex with the agent lowering the effective concentration. An anionic germicide would not be used with a cationic surfactant for obvious reasons. </div> <bR> <div> The choice of temperature at which a germicide should be used is very complex as chemical activity increases with increasing temperature but growth of most microorganisms increase with temperature also. In most cases, the chemical activity increases faster than the growth but not always. If the temperature is high enough, many organisms are destroyed without the intervention of a germicide.</div> <bR> <div> <B><U>Classifications of Germicides</U></B></div> <bR> <div> <B>Quaternary Ammonium Compounds</B></div> <bR> <div>      Quaternary ammonium compounds were first introduced in the 1930's and are both surfactants and germicides.  The structure of these compounds consists of a lipophilic long chain alkyl or polycyclic group, a benzyl, pyridine or quinoline type group and two methyl groups making a quaternary amine structure.  The amine is solubilized with a positive anion such as Na, K, NH4 etc. to form a cationic surfactant.  The main features of these germicides are they contain no heavy metals, chlorine, phenol, or iodine.  They are odourless, colourless, highly stable, and virtually non-toxic.  They are effective against most gram-positive and some gram-negative bacteria but are ineffective against spores, fungi, viruses such as PBFD or polyoma, mycobacteria and pseudomonas. </div> <div> Quaternary ammonium compounds function by causing the disintegration of cell walls by their detergent action targeting phospholipids. They have also been found to interfere with cell respiration and glycolysis inhibiting the oxidation of carbohydrates.</div> <div> A large number of products containing quaternary ammonium compounds are available.</div> <div>      Examples:</div> <div> Benzalkonium A,  Roccal,  Zephiran Chloride: </div> <div> <FONT SIZE="3" COLOR="#000000" FACE="Arial" >Alkyl Dimethylbenzyl Ammonium Chloride [C</FONT>6H<FONT SIZE="1" COLOR="#000000" FACE="Arial" >5CH</FONT><FONT SIZE="1" COLOR="#000000" FACE="Arial" >2N(CH</FONT><FONT SIZE="1" COLOR="#000000" FACE="Arial" >3)</FONT><FONT SIZE="1" COLOR="#000000" FACE="Arial" >2 C</FONT><FONT SIZE="1" COLOR="#000000" FACE="Arial" >12H</FONT><FONT SIZE="1" COLOR="#000000" FACE="Arial" >25 ]Cl</FONT></div> <div> Used as an antiseptic at 0.01 - 0.1% concentration for cleaning wounds and skin. It is not recommended for equipment or instrument disinfection.</div> <div> <B> </B></div> <div> Summary:</div> <bR> <div>      Use:</div> <div> Quaternary ammonium compounds are used for surface and equipment decontamination at 0.05-1.5% concentration for 10-30 minutes and for wound and skin cleansing. </div> <div>      Advantages:</div> <div> Quaternary ammonium compounds have a combined detergent and germicidal action with low toxicity when diluted. </div> <div> Disadvantages:</div> <div> Problems with quaternary ammonium compounds are limited activity with viruses, fungi, gram-negative bacteria, spores, and mycobacteria. Most quaternary ammonium compounds are not biodegradable and some support bacteria growth. </div> <div>      Application to aviculture:</div> <div> Roccal has been used for general disinfection of cages and hand feeding equipment. As this type of germicide is ineffective on the common avian viruses, fungi and Pseudomonas bacteria, its use is not recommended.</div> <bR> <bR> <div> <B>Phenolics</B></div> <bR> <div>      The germicidal properties of phenol were discovered by Lister in 1867.  Phenol is one of the most studied of the germicides and is used as a standard for comparison for germicides. The phenol coefficient is a comparison of the effectiveness of a germicide compared to 5% pure phenol using a number of standard procedures. Phenol is rarely used today but its derivatives are very popular. All phenol derivatives are both bacteriostatic and bactericidal depending on the concentration. Phenols are protein denaturants and protoplasm poisons. Many are insoluble and their effectiveness is very low indicating that solubility is an indicator of germicidal activity. Preparing a sodium salt will increase solubility but also decrease effectiveness.  The germicidal activity increases with temperature and lowering of pH but decreases with the presence of oils and organic material. </div> <div>      There are a large number of phenol derivatives that have been evaluated as germicides. To increase effectiveness of phenol, additional groups can be added to the phenol molecule. The effectiveness (phenol coefficient) increases with the addition of longer chain alkyl groups, nitro, and halogens. The diphenols (Bis-phenols) are also effective especially with hydroxyl groups on each phenol and again added halogens. Their action is different. They cause cell wall leakage in addition to being protein denaturants. The diphenylalkanes are also effective germicides and include dichlorophene, tetrachlorophene, and hexachlorophene. Bridging two phenols with a sulfur and chlorinating (bithionol) or bridging with a urea group and chlorinating (TCC) or bridging with a guanidino group (Hibitane) result in bacteriostatic compounds active as low as 1:1,000,000 dilution. These compounds are used in disinfectant soaps. </div> <div> Hibitane is chlorhexidine gluconate and is sold under the names Hibistat, Nolvasan, and Virosan.  Hibitane is effective against many bacteria and yeasts but not against most viruses, mycobacteria spores, and Pseudomonas. It is a suspected carcinogen. Its effectiveness is enhanced by the addition of alcohol.  </div> <div>      Most phenol germicides are combinations of phenols.  A number of commercial phenol products are available:</div> <div>  </div> <div> 1-Stroke Environ: 14.5%Na o-phenylphenol, 12.5%p-tert-amylphenol</div> <div> Environ - H: 3.3% 2-benzyl- 4-chlorophenol, 0.8% 4-tertamylphenol, 3.9% phenylphenol</div> <div> Lysol spray: 79% ethanol, 0.1% o-phenylphenol</div> <div>      Lysol: 2.8% phenylphenol, 2.7% 2-benzyl-4-chlorophenol</div> <div>      Dettol: chloroxylenol</div> <bR> <div> Summary:</div> <bR> <div>      Phenolics:</div> <div>      Use:</div> <div> Phenolics are used for general cleaning and disinfecting of premises and instruments at 0.05 - 1.5% concentration for 10-30 minute exposure time. They are also additives to soaps and lotions. </div> <div>      Advantages:</div> <div> Phenolics are tolerant of organic debris and hard water. They leave an active residue on surfaces and are generally biodegradable.</div> <div>      Disadvantages:</div> <div> Phenolics have pungent odours, are corrosive, toxic and limited activity on viruses and spores. Care must be used around cats and reptiles, as phenols are very toxic to these animals. Hexachlorophene is a potent carcinogen.</div> <div>      Application to aviculture:</div> <div> Phenols are used for general disinfection of aviary equipment but objects treated must be rinsed thoroughly. Sufficient ventilation is necessary.</div> <bR> <div> Chlorhexidine:</div> <div>      Use:</div> <div> Phenolics are used for general cleaning and disinfecting of premises and instruments at 0.05 - 1.5% concentration for 10-30 minute exposure time. They are also additives to soaps and lotions. </div> <div>      Advantages:</div> <div> Chlorhexidine is tolerant of organic debris and hard water. It is safe on skin and wounds. It leaves an active residue on surfaces and is generally biodegradable.</div> <div>      Disadvantages:</div> <div> Chlorhexidine is ineffective against many bacteria including Pseudomonas, non-enveloped viruses, spores, and mycobacteria. Virosan is effective against Pseudomonas. It is unstable and solutions must be made up each day.</div> <div>      Application to aviculture:</div> <div> Chlorhexidine products are relatively non-toxic to birds and are considered safe for avian use.</div> <bR> <div> <B>Chlorine</B></div> <bR> <div>      Chlorine, other than when used as a gas in water purification, is utilized as a water solution of either sodium or calcium hypochlorite or an organic compound that dissociates into chlorine when in solution. Standard laundry bleach is a 5.5% solution of sodium hypochlorite and is the least expensive readily obtainable germicide in use today. When applied properly it is capable of sterilization. It acts by entering the cell and attacking the sulphydryl groups of essential enzymes. In sunlight it breaks down to free radicals, which react with cell proteins. The reactive species is HOCl; thus, low pH is necessary for the highest bactericidal activity. A pH5 is optimal and lower pH results in loss of chlorine gas from solution. There is no bacteriostatic action with hypochlorite. Vegetative cells are killed quickly. Fungi are more resistant than bacteria as are viruses and spores. At 100ppm available chlorine virtually all bacteria, spores, fungi, algae, protozoa, and viruses are killed given a long enough contact time. </div> <div>      As long as there is sufficient available chlorine, hypochlorite solutions are very effective in the presence of organic matter. The organic matter does decrease the effectiveness of hypochlorite since organic matter reacts with hypochlorite lowering the available chlorine. The ability of hypochlorite to react with organics allows hypochlorite germicides to penetrate organic barriers around organisms where other germicides would be ineffective.</div> <div> There are a number of inorganic and organic chemicals that break down in water releasing chlorine. These range from Chloramine T (sodium p-toluenesulphochloramide) to the isocyanurates (Dichloroisocyanuric acid and its salts). One chemical used in swimming pools is Sodium dichloro-s-triazinetrione, which is 55% available chlorine.</div> <div>      Chlorine dioxide is also used as a water solution for disinfection. Chlorine dioxide is used instead of chlorine in water purification in Europe because it does not form carcinogens such as trihalomethanes, chlorophenols and chloramines as does chlorine and is more effective.  Chlorine dioxide has been shown to inactivate avian polyomavirus. The chemical is available in a number of forms from Oxyfresh.</div> <bR> <div> Summary:</div> <bR> <div> Hypochlorite:</div> <bR> <div>      Uses:</div> <div> Sodium Hypochlorite solution is used as a general disinfectant, for surface decontamination and instrument disinfection at a concentration of 0.01 - 1% free chlorine for 10-60 minutes. </div> <div> Calcium hypochlorite powder is used in solution the same as the sodium salt.</div> <div>      Advantages:</div> <div> Hypochlorite solutions kill a wide spectrum of organisms including fungi, bacteria and viruses. It is inexpensive, widely available and works at low temperatures.</div> <div> The calcium salt is more stable with a longer shelf life than the sodium salt.</div> <div>      Disadvantages:</div> <div> Hypochlorite solutions are toxic, corrosive to skin and metals, and are unstable at the optimum pH 6.0. They are inactivated by organic material and are broken down by light and heat.</div> <div>      Application to aviculture:</div> <div> Hypochlorite solutions are commonly used to clean cages, perches, toys and feeding equipment because of its low cost and effectiveness. Precleaning and good ventilation are necessary when using hypochlorite.</div> <bR> <div> Dry chlorine compounds:</div> <bR> <div>      Uses: </div> <div> The uses are the same as with hypochlorite.</div> <div>      Advantages:  </div> <div> The bound chlorine compounds are more stable than hypochlorite at pH 6.0.</div> <div>      Disadvantages:</div> <div> The disadvantages are the same as with hypochlorite.</div> <div>      Application to aviculture:</div> <div> Dry chlorine compounds are used the same as hypochlorite to clean cages, perches, toys and feeding equipment. Precleaning and good ventilation are necessary. Dry chlorine can be added to dishwashers to disinfect feeding dishes.</div> <bR> <div> Chlorine Dioxide:</div> <div>      Uses: </div> <div> Solutions of this gas are used the same as hypochlorite solutions and the gas is a sterilant.</div> <bR> <div> Advantages:</div> <div> Chlorine Dioxide solutions have longer activity, are less corrosive and toxic than other chlorine compounds. These solutions can be used from pH 6-10.</div> <div>      Disadvantages:</div> <div>           Chlorine Dioxide solutions are unstable with light.     </div> <div>      Application to aviculture:</div> <div> Chlorine dioxide solutions such as Oxyfresh can be used as general purpose disinfectants for all aviary equipment as long as good ventilation is used.</div> <bR> <div> <B>Aliphatic Alcohols</B></div> <bR> <div>      Alcohols, and in particular ethanol, have been used for centuries to clean wounds even before the germ theory of infection was generally accepted.  They are reasonably good germicides and cause little damage to skin. Alcohols denature proteins and solubilize cell lipids. They also inhibit metabolism slowing cell growth. Alcohols function best in the presence of water thus only the water soluble alcohols are good germicides. Methanol is not as effective as ethanol. As you increase the chain length beyond C5, the effectiveness decreases along with solubility in water. The recommended concentration for ethanol and the C3 alcohols is 50 to 70%. Pure alcohol is a poor germicide. At 50%, alcohols are good bactericides though to be effective on fungi and some viruses the concentration should be 70% with a 10-30 minute exposure. A 2% solution will slow growth of many bacteria. One problem is the high volatility of low molecular weight alcohols resulting in no residual germicidal effect. </div> <div> Alcohols are good solvents for many other types of germicides (tinctures) resulting in a combined effectiveness.  Examples are tincture of iodine and Mercurochrome.  Others are Lysol spray (see Phenols) and Enviroquat (see Quaternary Ammonium) The most commonly used alcohols are ethanol and isopropanol.</div> <div> Summary:</div> <bR> <div> Use:</div> <div> The most common alcohols used are 70-80 % ethanol and 60-95% isopropanol. These are used for surface decontamination, hand wash and instrument cleaning with a contact time of 10-30 minutes.</div> <div> Advantages:</div> <div>      Ethanol and isopropanol have low toxicity, low residue and are non-corrosive.</div> <div> Disadvantages:</div> <div> These alcohols are flammable, irritate eyes and have solvent action on rubber and plastics.</div> <bR> <div> <B>Peroxides</B></div> <bR> <div>      Many peroxides have been used as germicides including hydrogen peroxide and peracetic acid. Hydrogen peroxide is a strong oxidizing agent, which reacts with cell proteins. It is sold as a 3-30% solution in water containing stabilizers. The low concentrated solutions have been used as antiseptics on skin and wounds whereas the higher concentrations burn the skin. Hydrogen peroxide is active against most microorganisms but is not as active against viruses. It is quickly inactivated by organic materials, light and heat. </div> <div>      Peracetic acid has been used in water solution and as an aerosol or vapour for sterilization since 1951. It is a good sporicide and bactericide. It is sold as a 40% solution in vented caps because of decomposition into oxygen and acetic acid. Peracetic acid corrodes most metals and oxidizes proteins and other organic compounds. The reactivity of peracetic acid is similar to hypochlorite but leaves no residue. The decomposition products are non-toxic.</div> <bR> <div>  </div> <div> Summary:</div> <bR> <div> Hydrogen Peroxide:</div> <div> Use:</div> <div> Peroxides are generally used for surfaces, instrument and equipment decontamination. Hydrogen peroxide is used as a 3-30% aqueous solution with contact time 10-60 minutes. </div> <div> Advantages:</div> <div> It is odourless, environmentally safe and low in toxicity. </div> <bR> <div> Disadvantages:</div> <div> Hydrogen peroxide has limited sporicide activity, an irritating vapour and is corrosive to metals. It can be explosive at high concentrations. </div> <bR> <bR> <bR> <div> Peracetic acid </div> <div> Use:</div> <div> Peracetic acid is formulated as a .001-3% aqueous solution or a 2-4% gas phase fumigant with contact times between five and 120 minutes. </div> <bR> <div> Advantages:</div> <div> Peracetic acid is a broad spectrum germicide for instruments and equipment, killing bacteria and spores at low temperatures. It is insensitive to organic debris and dirt, is fast acting, nontoxic and leaves no residue. </div> <div> Disadvantages:</div> <div> Peracetic acid has a pungent odour, is corrosive to metals, irritating to skin and eyes and has a short shelf life in solution of less than a week. The vapour is a fire hazard above 55C. </div> <div>  </div> <div> <B>Inorganics</B></div> <bR> <div>      Inorganic germicides include compounds such as sodium chlorite and potassium persulfate.  Sodium chlorite has been used in water disinfection. Potassium persulfate is a new product sold as Virkon S in Europe and North America.</div> <div>  Virkon is a mixture of Potassium persulfate oxidizer, a surfactant and a buffer. In clinical trials. A 2% water solution was effective on 102 types of fungi, 402 strains of bacteria and all families of viruses affecting man and animals. A 1% solution is non-irritating to eyes and skin and is biodegradable. A redox indicator is included to show the potency of the solution. The product has been advertised as a replacement for glutaraldehyde in hospitals and a replacement of formaldehyde for fumigation. Potassium persulfate is an oxidizing agent similar to chlorine of hydrogen peroxide and acts by denaturing proteins in cells.</div> <bR> <div> Summary:</div> <bR> <div>      Uses:</div> <div> Potassium persulfate germicides are used to disinfect or sterilize instruments and equipment at a concentration of 1-2% in water. The solution can be aerosolized to act as an area fumigant. </div> <bR> <div>      Advantages:</div> <div> Potassium persulfate germicides are non-irritating to skin and eyes. They are useful for a very wide selection of microorganisms and can sterilize.</div> <div>      </div> <div>      Disadvantages:</div> <div> Potassium persulfate germicides are quite expensive and difficult to obtain. The solution is corrosive to some metals.</div> <bR> <div>      Application to aviculture:</div> <div> Virkon type germicides can be used for general cage, premises cleaning, and disinfection. The solution does not have to be washed from surfaces and can be used with caution on equipment and hand feeding instruments. During the aftermath of a hurricane in Florida, a Virkon solution was sprayed on birds to combat molds and fungi with no adverse after effects.</div> <bR> <div> <B>Iodine</B></div> <bR> <div>      Iodine was first used as an antiseptic in the 1830's. It was originally prepared as a tincture - 1 oz iodine in 1 pint of ethanol for use as an antiseptic on the skin for wounds, to sterilize surgical dressings and instruments and to disinfect hands before surgery. It has been used to disinfect drinking water and in swimming pools. Today iodine is used as an Iodophor, a combination of iodine and a carrier which allows the slow release of free iodine into solution. These mixtures do not cause the allergic reactions that iodine commonly does. An example of an iodophor is PVP-Iodine, which is a mixture of polyvinylpyrrolidine and iodine sold as betadine or Isodene. In water, iodine is slowly released. Other carriers include non-ionic surfactants that are less irritating than iodine by itself.  Iodophors are used solution diluted with water to a concentration of 25-75ppm free iodine. Iodine solutions are very good anti-parasitic and are used against trichomonas and amebic dysentery.  Iodophores are also effective against many viruses, bacteria spores, fungi and algae. </div> <div> The active agent in Iodophores is elemental iodine, which iodates tyrosine residues in cells. Iodine also oxidizes, precipitates and destroys proteins. Iodine is about six times as effective as chlorine.  Iodine is most effective in acid pH to neutral and is ineffective in alkaline solutions.</div> <bR> <div> Summary:</div> <div>      Use:</div> <div> Iodophor solutions are formulated as 10 -100ppm iodine slightly acidic. Contact times are 3-30 minutes. Iodophors are used as antiseptics on skin because of their low toxicity and tolerance to organic material and for disinfection of instruments and equipment </div> <bR> <div>      Advantages: </div> <div> Iodophors are low in toxicity, effective for a wide range of organisms, tolerant to organic contamination, non-irritating and are active in both warm and cold water.</div> <bR> <div>      Disadvantages:</div> <div> Iodophors are expensive, stain some types of plastics, do corrode some metals (Al, Cu. Ag) and will release irritating iodine vapour if heated above 43C. </div> <bR> <div>      Application to aviculture:</div> <div> Iodine disinfectants used include Betadine, Vanodine, Povidone and Scrubodyne. Iodophors have been used on skin and as a surface cleanser. Iodophors are not effective against Pseudomonas bacteria, PFBD and polyoma viruses.      </div> <bR> <div> <B>Aldehydes</B></div> <bR> <div>      The two most common aldehyde germicides are glutaraldehyde and formaldehyde.</div> <div>      Glutaraldehyde is a dialdehyde with formula CHO-CH2CH2CH2-CHO. Use of this chemical began in the 1960's and has become the standard for liquid chemical sterilization. It is more effective than formaldehyde for killing spores. Glutaraldehyde is formulated as a 2% solution alkaline in pH for sterilizing medical instruments, as it does not affect cements, rubber and most plastics, coagulate blood or other proteins and has a low vapour pressure. Glutaraldehyde does not dull the edges of cutting instruments. It has been considered a safe germicide for many years though reports are now appearing showing this chemical to be causing allergic reactions. Consequently, the allowable concentration of vapour has been set at .05 PPM for an 8 hour exposure limiting its use as a general purpose disinfectant. Aldehydes act as alkylating agents on proteins and in low concentrations are biostatic. </div> <div>      Formaldehyde (HCHO), as formalin solution, has been used as a fixative for preserving biological specimens since the last century. Formaldehyde is much more effective when mixed with an alcohol though it is not as effective at the same concentration as glutaraldehyde. Formaldehyde is used as a 5-20% solution and it will kill most microorganisms including spores and viruses. It will sterilize at 25C in 24 hours. The vapour is very pungent, irritating and toxic, thus it is not used as a general-purpose disinfectant. </div> <bR> <div> Summary:</div> <bR> <div>      Uses:</div> <div> Glutaraldehyde is formulated as a 0.5 - 2.5% aqueous solution of alkaline pH. The contact time is 2 - 30 minutes with 12 hours for sterilization including spores. Formaldehyde solutions are either 1-20% in water or 70-90% alcohol. The contact time is 10-30 minutes with 24 hours for sterilization including spores. </div> <div> These chemicals are sold as cold sterilants and fixatives. They are used for surface disinfection and for instruments and equipment.</div> <bR> <div>      Advantages:</div> <div> Glutaraldehyde and formaldehyde have a very broad spectrum of activity to the point of being sterilants. They are non-corrosive to metal and will tolerate organic material.</div> <bR> <div>      Disadvantages:</div> <div> Glutaraldehyde and formaldehyde have pungent odours. They are toxic to skin, eyes and the respiratory system. They are suspected carcinogens. Glutaraldehyde solutions are pH and temperature dependent, have a two-week shelf life and are expensive.</div> <div> Formaldehyde is much less expensive than glutaraldehyde.</div> <bR> <div>      Application to aviculture:</div> <div> Aldehydes have been used as surface disinfectants and for sterilizing feeding syringes and instruments. Glutaraldehyde is capable of sterilization and is effective against all bacteria, spores and viruses in higher concentrations. This chemical can be dangerous to work with as it is a suspected carcinogen and damages skin, respiratory system and mucous membranes. Gloves and very good ventilation is mandatory.  These chemicals are not recommended for general use. </div> <bR> <div> <B>Fumigants</B></div> <bR> <div> A number of chemicals in the gas phase have been used for sterilization of equipment and instruments. They are used to replace heat sterilization where high heat would damage the item to be sterilized. Three gases are most commonly used: ethylene oxide, formaldehyde and â-Propiolactone. All three of these gases must be used with caution, as they are all very toxic and irritating. Many hospitals do not use this method on site any more and depend on specialty services for sterilizing equipment with these gases.</div> <div> Ethylene oxide has been used since the 1940's to sterilize medical equipment and supplies. Special sterilization cabinets are available with built-in controls for gas concentration, humidity, temperature and pressure which has automated the sterilization process. Under proper conditions, total sterilization including spores can be achieved. Problems can arise because the gas does not penetrate all surfaces and spores and viruses can be protected by impermeable contaminants. In addition, a number of bacteria in the spore stage are developing resistance to this gas. </div> <div> Formaldehyde gas has been used since the 30's to sterilize instruments and equipment. Formaldehyde has very high sterilizing ability as long as the humidity is high. This gas is also has poor penetrating ability and has been replaced for most applications with ethylene oxide.</div> <div> â-Propiolactone is the newest of the gas sterilizers introduced in the late 1950's. The gas is effective against spores depending on the humidity >70%. â-Propiolactone is extremely toxic and carcinogenic though the hydrolysis product during use, â-hydroxyp<FONT SIZE="3" COLOR="#000000" FACE="Arial" >roprionic acid, is much less toxic and not carcinogenic. </FONT></div> <div>      </div> <div> Summary:</div> <bR> <div>      Uses: </div> <div> These gases are used where sterilization of equipment and instruments is not possible using liquids and heat.</div> <bR> <div>      Advantages: </div> <div>           Total sterilization is possible with correct application.</div> <bR> <div>      Disadvantages:</div> <div> These gases are extreme irritants and toxins. Specialized equipment is necessary for their application. There is also the possibility of corrosion.</div> <div>      </div> <div>      Application to aviculture:</div> <div> Very large breeding facilities with resident veterinarians may be able to use these gasses for sterilizing brooders, incubators and other equipment. One application is the use of potassium permanganate and formalin, which release formaldehyde gas, to sterilize incubators and brooders. This method can be carried out safely outdoors with extreme caution.</div> <bR> <div> <B><U>Claims</U></B></div> <bR> <div>      There are many articles on the Web concerning the use of disinfectants. Very few of these articles have references to clinical studies on the effectiveness of the germicides. One exception is the product Virkon-S, which is fully documented. Many of the articles are concerned with the use of germicides in aviculture. Again, there are few references given to investigate claims made.</div> <bR> <div>      After many complaints in the USA about disinfectants, the EPA began a program of testing the effectiveness of disinfectants and sterilants for use in hospitals.  A number of products were found ineffective as claimed resulting in the product being removed from sale.  They include: </div> <div> Clidox-S, </div> <div> Perfecto Germ-X/Ucarcide 602; </div> <div> Cetylcide-G; </div> <div> Wavicide-01 Concentrate; </div> <div> Alcide Exspor; </div> <div> Alcide ABQ; </div> <div> Bionox; </div> <div> Coldspor/Colcide 10;</div> <div> Sporicidin; </div> <div> Metricide Activated Dialdehyde Solution; </div> <div> Metricide Plus 28;</div> <div> Metricide Plus 14; </div> <div> Metricide Plus 30.</div> <div> Broadspec 128</div> <bR> <div> The following line of products were pulled from the market because of failing to perform as advertised:</div> <bR> <div> Wipe Out Disinfectant Towelettes;</div> <div> QuickKit Biological Fluid Emergency Spill kit;</div> <div> Wipe Out Household or Office Disinfectant Spray; </div> <div> Wipe Out Medi Disinfectant Wand; </div> <div> Wipe Out Infection Control Travel kit; </div> <div> Wipe Out Spray. </div> <div> Wipe Out Cold Sterilizing Disinfecting Solution</div> <bR> <div> The US FDA publish a list of accepted sterilants and high level disinfectants which include as of January 2000:</div> <bR> <div> Cidex® OPA Solution High Level Disinfectant, (0.55% <I>ortho</I>-phthaldehyde)  </div> <div> Sporicidin Sterilizing and Disinfecting Solution (0.95% glutaraldehyde and 1.64% phenol/phenate),  </div> <div> <FONT SIZE="3" COLOR="#000000" FACE="Arial" >Cidex</FONT>TM Activated Dialdehyde Solution (2.4% glutaraldehyde),   </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Cidex Formula 7</FONT>TM Long-Life Activated Dialdehyde solution (2.5% glutaraldehyde),  </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Cidex Plus</FONT>TM 28 Day Solution (3.4% glutaraldehyde),   </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Metricide</FONT>® Activated Dialdehyde Solution (2.6% Glutaraldehyde),   </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Metricide Plus 30</FONT>® Long-Life Activated Dialdehyde Solution (3.4% Glutaraldehyde </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Metricide</FONT>® 28 day Long-Life Activated Dialdehyde Solution (2.5% glutaraldehyde),  </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Procide</FONT>® 14 N.S. (2.4% glutaraldehyde),  </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Omnicide</FONT>TM Long Life Activated Dialdehyde Solution ( 2.4% glutaraldehyde),   </div> <div> <FONT SIZE="1" COLOR="#000000" FACE="Arial" >Omnicide</FONT>TM Plus (3.4% glutaraldehyde),  </div> <div> Wavicide<FONT SIZE="1" COLOR="#000000" FACE="Arial" >® - 01 (2.5% glutaraldehyde),  </FONT></div> <div> STERIS 20TM Sterilant (0.2% peracetic acid),  </div> <div> PeractTM 20 Liquid Sterilant/Disinfectant (0.08% peroxyacetic acid and 1.0% hydrogen peroxide </div> <div> SporoxTM Sterilizing & Disinfection Solution (7.5% hydrogen peroxide),  </div> <div> MedSci 3% Glutaraldehyde (3% glutaraldehyde),  </div> <div> Cetylcide-G® Concentrate and Diluent Concentrate (3.2% glutaraldehyde),  </div> <bR> <div>      One thing to notice is that some of the products tested and accepted by the FDA are not accepted by the EPA.</div> <bR> <div> The following information is contained in an article on disinfectant use for aviaries. The section is referring to the use of glutaraldehyde (Wavicide):</div> <div> Totally effective against ALL pathogens. Equally effective in cold, hot and hard water. Effective in the presence of organic debris. Skin irritation is minimal even at 2%. Rated by the EPA as the lowest tissue irritation level possible, non-toxic and non-teratogenic, Wavicide has proven to be the best combination of stability, ease of application, range and speed of destruction of pathogens, safety for both humans and animals, long shelf life, economy, reusability, ease of application and safety. Highly recommended for aviary and nursery use. </div> <div> <U>www.multiscope.com/hotspot/howcln5.htm</U></div> <bR> <div>      Articles that are more recent tend to dispute these claims concerning the safety of this chemical.</div> <bR> <div> "Use of glutaraldehyde in the medical sector has revealed serious and wide ranging health risks to operators including dermatitis (allergic reactions to the skin), rhinitis, conjunctivitis and asthma. The report refers to many scientific papers and incidents including court cases where nurses have been awarded compensation after losing their jobs following sensitization to glutaraldehyde. Its use and exposure are being increasingly regulated. For example in the UK, glutaraldehyde is one of the substances covered by the Control of Substances Hazardous to Health Regulations (COSSH). The Health and Safety Commission recently released a "Chemical Hazard Alert Notice" for glutaraldehyde recommending that a Maximum Exposure Limit (MEL) of 0.05 ppm, expressed as an 8-hour time weighted average and 0.05 ppm, expressed as a 15-minute reference period should be set."</div> <div>  </div> <div> "The dangers of the use of glutaraldehyde were publicized in a court case in 1989 when a nurse was awarded £1,000 by a Health Authority after being `permanently sensitized to the disinfectant glutaraldehyde'. She was exposed to the fumes whilst disinfecting instruments and developed breathing difficulties on exposure to glutaraldehyde. </div> <div> A review article in the British Medical Journal outlined some of the occupational risks of using glutaraldehyde. The article stated: </div> <div> `There are now, however, several studies describing disease among exposed workers, even when the degree of exposure is well below the recommended limits' </div> <div> <FONT SIZE="3" COLOR="#000000" FACE="Arial" >Norback investigated 107 medical staff exposed to glutaraldehyde and compared their symptoms with those of matched and unexposed controls. He found a significant excess of nasal and throat symptoms, nausea and headache, and rashes on the hands of medical personnel. The symptoms increased with exposure.: those who had used glutaraldehyde most had three times as many symptoms as those who had used it least. All the workers were exposed to less than 0.8 mg/m</FONT>3 (0.2 parts per million) - the Swedish and British original limit. </div> <div> Jachuck studied eight workers in an endoscopy unit after two of them presented with symptoms. Unlike the Swedish study they also studied respiratory symptoms. One worker had airways obstruction, six rhinitis, six eye irritation, and three dermatitis. Again they had been exposed to less than the recommended original occupational limit."</div> <bR> <div> These articles point out the differences between what is acceptable practice in the USA compared to Great Britain. </div> <bR> <div> <B><U>Conclusion</U></B></div> <bR> <div>      The choice of what germicide to use depends on many factors. Few products are safe, effective and inexpensive. Personal experience with a number of the mentioned agents has convinced the author to use only three germicides in a commercial aviary: Virkon for general cleaning and disinfection, 1/9 bleach for sterilizing instruments and foot baths, and formaldehyde for fumigation. In the future, a method of fumigating with Virkon mist will be investigated as formaldehyde is not a good penetrating agent and is very toxic.</div> <div> <B><U>Comments</U></B></div> <bR> <div>      When writing this report it was expected that large amounts of information would be found on the web from manufacturers and suppliers of germicides. In fact, little was found in the search. The Virkon site is very extensive but little else was found. Many of the articles about disinfection contained the same information using the same words. It is suspected that most of the articles were based on information from UCDavis - <FONT SIZE="1" COLOR="#0000FF" FACE="Arial" ><U>www.vetnet.ucdavis/vetext/INF-PO-Sanitation.html</U></FONT>. Other articles in symposium proceedings were found that also paraphrases this article. The amount of good information on the effectiveness of these products is very small making the formation of an educated opinion on the topic difficult.</div> <bR> <bR> <div> <B><U>References</U></B></div> <bR> <div> <B>Definitions</B></div> <div> Madigan, Michael T., Martinko, John M., Parler, Jack, Biology of Microorganisms, Ninth Edition(2000). Prentice Hall.G1-G14</div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 9-12</div> <bR> <div> <B>Pathogens</B></div> <div> Hugo, W. B., Inhibition and Destruction of the Microbial Cell (1971) Academic Press. 1-33</div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 15-30</div> <div> <FONT SIZE="3" COLOR="#000000" FACE="Arial" >Muser, Kay Katherine, Psittacine Nursery Management, 6</FONT>th Canadian parrot Symposium(1995) 63-67.</div> <div> Ritchie, Branson W.,DVM, PHD, Avian Viruses Function and Control. (1995) Wingers Publishing. 110-113</div> <bR> <div> <B>Quaternary Ammonium Compounds </B></div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 430-452</div> <div> Ritchie, Branson W.,DVM, PHD, Avian Viruses Function and Control. (1995) Wingers Publishing. 114-118.</div> <div> Hugo, W. B., Inhibition and Destruction of the Microbial Cell (1971) Academic Press. 95-104</div> <div> Muser, Kay Katherine, Psittacine Nursery Management, 6th Canadian Parrot Symposium(1995) 63-67.</div> <div> Borick, Paul M., Chemical Sterilization. (1973) Dowden, Hutchinson & Ross Inc. 205-229.</div> <div> http://www.sigma.sial.com/sigma/proddata/b1383.html </div> <div> http://steamatic-cr.com//Principles.html</div> <div> http://vetnet.ucdavis/vetext/NF-PO-Sanitation.html</div> <div> http://www.wingedwisdom.com/ww6eiv.html</div> <div> <B><U>Phenolics</U></B></div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 401-429</div> <div> Sykes, S. (1965) Disinfection and Sterilization. 311-331.</div> <div> Ritchie, Branson W.,DVM, PHD, Avian Viruses Function and Control. (1995) Wingers Publishing. 114-118.</div> <div> <U>http://www.wingedwisdom.com/ww6eiv.htm</U></div> <div> <U>www.vetnet.ucdavis/vetext/INF-PO-Sanitation.html</U></div> <bR> <div> <B>Chlorine:</B></div> <div> Ritchie, Branson W.,DVM, PHD, Avian Viruses Function and Control. (1995) Wingers Publishing. 114-118.</div> <div> Sykes, S. (1965) Disinfection and Sterilization. 381-410.</div> <div> Hugo, W. B., Inhibition and Destruction of the Microbial Cell (1971) Academic Press. 137-181</div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 278-304</div> <div> Muser, Kay Katherine, Psittacine Nursery Management, 6th Canadian Parrot Symposium(1995) 63-67.</div> <div> <U>www.vetnet.ucdavis/vetext/INF-PO-Sanitation.html</U></div> <bR> <div> <B>Alcohols:</B></div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 237-252</div> <div> Sykes, S. (1965) Disinfection and Sterilization. 341-345.</div> <div> Muser, Kay Katherine, Psittacine Nursery Management, 6th Canadian Parrot Symposium(1995) 63-67.</div> <bR> <div> <B>Peroxides:</B></div> <div> Borick, Paul M., Chemical Sterilization. (1973) Dowden, Hutchinson & Ross Inc. 146-149</div> <div> Hugo, W. B., Inhibition and Destruction of the Microbial Cell (1971) Academic Press. 253-254</div> <bR> <div> <B>Inorganics:</B></div> <div> Muser, Kay Katherine, Psittacine Nursery Management, 6th Canadian Parrot Symposium(1995) 63-67.</div> <div> http://www.antecinc.com</div> <bR> <div> <B>Iodine:</B></div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 329-347</div> <div> Ritchie, Branson W.,DVM, PHD, Avian Viruses Function and Control. (1995) Wingers Publishing. 114-118.</div> <div> Hugo, W. B., Inhibition and Destruction of the Microbial Cell (1971) Academic Press. 137-181.</div> <div> Muser, Kay Katherine, Psittacine Nursery Management, 6th Canadian Parrot Symposium(1995) 63-</div> <div> 67.</div> <div> <U>http://www.wingedwisdom.com/ww6eiv.htm</U></div> <div> http://<FONT SIZE="1" COLOR="#0000FF" FACE="Arial" ><U>www.vetnet.ucdavis/vetext/INF-PO-Sanitation.html</U></FONT></div> <div> <B>Aldehydes:</B></div> <div> Ritchie, Branson W.,DVM, PHD, Avian Viruses Function and Control. (1995) Wingers Publishing. 114-118.</div> <div> Muser, Kay Katherine, Psittacine Nursery Management, 6th Canadian Parrot Symposium(1995) 63-67.</div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 484-485.</div> <div> Borick, Paul M., Chemical Sterilization. (1973) Dowden, Hutchinson & Ross Inc. 155-162</div> <div> <U>www.vetnet.ucdavis/vetext/INF-PO-Sanitation.html</U></div> <bR> <div> <B>Fumigants:</B></div> <div> Hugo, W. B., Inhibition and Destruction of the Microbial Cell (1971) Academic Press. 226-282</div> <div> Lawrence, Carl A., Block, Seymore S. (1968), Disinfection, Sterilization, and Preservation. Lea & Febiger, 670-671.</div> <bR> <div> <B>Claims:</B></div> <div> Blackwell, Mark MA VetMB MRCVS,Issues Concerning the Use of Aldehydes as Disinfectants, Animal Health Division, Antec International </div> <div> http://www.epa.gov/pesticides/citizens/motherjq.html</div> <div> <U>http://www.fda.gov/cdrh/ode/germlab.html</U></div> <div>      </div> <bR> </td> </tr></table></body>