Hygiene and pathogens. A pathogen is a disease-causing organism and includes agents such as: bacteria viruses fungi parasites.

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1 The aim of cleaning Hygiene and pathogens Hygiene is concerned with the control of the pathogenic micro-organisms and preventing their entry into our bodies where they can cause disease. The aim of cleaning is to remove pathogens and prevent cross-contamination between animals. A pathogen is a disease-causing organism and includes agents such as: bacteria viruses fungi parasites. Pathogens exist everywhere and some have a great ability to survive in the environment. Some do this by the production of spores which are like very resistant seeds that can stay dormant in the environment until conditions allow them to multiply. Not all micro-organisms are pathogens. Most are, in fact, beneficial, including the bacteria that: live in animals intestines and help in the digestion of plant matter decompose plant and animal matter are used in the production of food like yoghurt, cheese and beer. Portals of entry into the body Disease or pathogens get into the body through: mucous membranes cuts on the skin the respiratory tract the gastro intestinal tract. 1

2 Diseases are transmitted by air (on the wind) vapour and droplet (coughing and sneezing) and by direct contact (touching). The aim of cleaning and disinfection of areas where animals are kept is to minimise the transmission of these diseases, some of which include: kennel cough parvovirus ringworm mange. Good general clinic hygiene and cleanliness is the foundation for aseptic technique. Cleaning methods All animals require an hygienic environment to remain healthy. Where there are large numbers of animals and the population changes constantly, the likelihood of cross-infection is greater, so implementing an effective cleaning and disinfection routine is extremely important. Removal of gross contamination Removal of gross contamination is the first stage of cleaning and is necessary before applying disinfectants.the table below highlights the relative merits of some different gross cleaning methods. Cleaning method Dusting and sweeping Mopping Vacuuming Effectiveness Removes dust, dirt and debris; but will fling some into the air, where it can be inhaled by people and animals, or will simply settle again later. NOT ideal. Dry mopping is the same as dusting. Wet mopping is better for removing dust and debris. Disinfectant can be included; but mop heads can harbour micro-organisms. Mop heads may leave the area wet, leading to problems in reception. Can be hard to get into corners. Vacuuming is the method of choice for dusting and initial cleaning. This method effectively removes dirt and dust. 2

3 Wet vacuums can include liquids. Vacuums can get into corners. These cleaners can do shelves and benches. When Vacuuming, you should use liner bags to avoid the liberation of dust when emptying. One flaw is that vacuums can contribute to airborne particles. Other methods of removal of gross contamination include: emptying garbage bins removing animal waste extermination of pests such as mice, rats, cockroaches and flies. Detergents and disinfectants These are defatting agents that remove grease and may be combined with disinfectants. They reduce the amount of work needed by helping water to penetrate dirt and should have the following properties: quickly soluble non-corrosive soften water economical non-toxic biodegradable good wetting action emulsify fat dissolve organic matter easy to rinse. You must know your detergents, dirt and cleaning area! The action of chemical disinfectants is dependent upon being in direct contact with the target micro-organism, which means that all traces of organic material such as dirt, grease, faeces, urine, blood and vomit must be physically removed from the surface prior to disinfection. The action of some chemical agents is inhibited by the presence of organic material such as blood and faeces, which leads to ineffective removal of pathogens. 3

4 Methods of disinfection and sterilisation After the gross removal of contamination such as rubbish or animal waste, further cleaning may be carried out by using methods of disinfection or sterilisations which may be: physical dry heat moist heat steam ultrasonic vibration ultraviolet radiation ionising radiation filtration dilution chemical liquids gases. What are chemical disinfectants? Disinfectants are applied to the environment and equipment. Antiseptics are milder forms of disinfectants and are used on living tissue. Disinfectants and antiseptics will remove most pathogens, apart from heat-resistant spores and some viruses. Liquid disinfectants and antiseptics The main groups of liquid disinfectants are listed below: Chemical group Iodine Example Povidone-iodine 5% or 10% solution 7.5% scrub Spectrum of activity fungi, protozoa, yeast Problems Main use Residual activity Detergent in the scrub is cytotoxic Corrosive to metals organic matter Contact dermatitis and skin irritation which can increase postsurgical wound infections Surgical prep Wound irrigation Aqueous iodine As above and can Wound lavage 4-6hrs 4

5 Bisbiguanide Chlorhexidine as a scrub solution. As above except does not kill protozoa. Eye irritation Phenols Alcohols Aldehyde Quaternary ammonium Hydrogen peroxide Chlorine increase infection due to cell damage Stains Tincture of iodine As above Only for intact skin as it is too irritant Cytotoxic. Use for presurgical prep of skin, wound therapy Hexachloraphene Dettol Isopropyl alcohol 50% or 70% ethanol Glutaraldehyde Formaldehyde Benzalkonium chloride Savlon 1. Hypochlorite (bleach) 2. Chloramines (halamid) Disinfection of instruments Bacteria Bacteria and some fungi yeasts, spores (but only with prolonged contact 3 hours) Bacteria Minimal bactericidal action fungi 1 Unaffected by alcohol 2 Days binds to a protein in the skin surface Neurotoxicity from dermal exposure Neurotoxic Skin irritation Inhalation Irritant hypersensitivity Dermatitis Hypersensitivity Toxic if ingested Cytotoxic Can damage some surfaces by bleaching 2% iodine in 50% ethanol Onset of action on the skin is rapid Slow onset of action when applied to the skin alcohol Used alone or as a tincture organic matter 2% solution used for cold sterilisation of objects Must be thoroughly rinsed off due to toxicity Used for disinfection Should only be used once at the first irrigation of a contaminated wound Chloramines are less irritant to the skin Often used against ringworm Before using chemical disinfections you should be aware of the OHS precautions and requirements for the use of protective clothing. Up to 2 days as it evaporates 5