Water Pollution Final Lectures Arabic PDF

PUBLIC HEALTH For Pharmacy Students Water Pollution Dr/Mohammed A. Al-Kholani 156  Water Pollution Water Requirement(Adequate): The basic physiological requirements for drinking water have been estimated at about 2 lit...

PUBLIC HEALTH For Pharmacy Students Water Pollution Dr/Mohammed A. Al-Kholani 156  Water Pollution Water Requirement(Adequate): The basic physiological requirements for drinking water have been estimated at about 2 liters per head per day ( for survival ) A daily supply of 150-200 liters per capita is considered as an adequate supply to meet for all domestic purposes Uses of water 1. Domestic purpose: drinking, preparing food, bathing, washing clothes, brushing your teeth, and watering the garden. 2. Public purpose 3. Agriculture purpose 4. Industry 5. Power production Dr/Mohammed A. Al-Kholani 7/28/2024 157 6. Carrying waste  Sources of water Water Pollution Not all of these sources are usable. We have to extract water from such a point in the water cycle so that it gives a safe yield (adequate for 95% time of the year), i.e. you can’t use a river that dries up in summer for a reliable source. So what do we do? 7/28/2024 Dr/Mohammed A. Al-Kholani 158  Water Pollution Sources of water supply Rain water Surface water Groundwater The prime source of Precipitation that Water located under the surface all water does not infiltrate the of the ground,.i.e. lies in many ground feet below the earth's surface or return to the atmosphere ▪ It is rain and surface water by evaporation such as the that permeates the layers of water in streams, rivers, the ground and comes out ponds, lakes and from springs and wells (deep impounding reservoirs & shallow). ▪ It is fed by rain (like rivers, ▪ Wells: Dug well, Tube well or lake, ponds), except the artesian rivers that originate in Himalayan glaciers). ▪ Originally free from ▪ It is much susceptible to all ▪ The cheapest and most contamination kinds of contamination practical means of providing ▪ Should be collected ▪ and as such can’t be used water to small communities properly to reduce without treatment ▪ Generally safe contamination 7/28/2024 Dr/Mohammed A. Al-Kholani 159 7/28/2024 Dr/Mohammed A. Al-Kholani 160  Sources of water supply Water Pollution Groundwater Wells There are two kinds of wells 1. Shallow wells are only as deep as the top soil and does not reach the layer of rocks (impervious stratum) of the ground. They are more prone to be polluted by activity of surface. 2. Deep wells run below the impervious stratum, and are usually more protected from contamination. 7/28/2024 Dr/Mohammed A. Al-Kholani 161  Water Pollution Water and health Many water sources in developing countries are unhealthy because they contain harmful physical, chemical, and biological agents. To maintain good health, however, not only must a water supply be safe to drink, o It must also be: 1. Available in sufficient quantity (for cooking, handwashing, personal bathing, cleaning and laundering clothes etc), 2. Easily and safely accessible by all the community (without the need to carry heavy containers of water over long distances or having to visit sites where insect vectors of disease breed), 7/28/2024 Cont. Dr/Mohammed A. Al-Kholani 162  Water Pollution Water and health o It must also be cont.: 3. Available all of the time (throughout the year) or when it is needed, 4. Available at affordable cost. o It should also meet local standards for taste, odour, and appearance. (all the above indicate the water required for a state of positive health and wellbeing) Safe and healthy water It is defined as ▪ Free from pathogenic agents and toxins ▪ Free from harmful chemical and physical substances ▪ Pleasant to the taste ▪ Free from color and odour ▪ Usable for domestic purposes Polluted or contaminated water - when it does not fulfill the above criteria. 7/28/2024 Dr/Mohammed A. Al-Kholani 163 Health education is required to explain the relationship between health, water, sanitation and hygiene. Community involvement is essential to protect water supplies from pollution and to perform basic surveillance and maintenance of water and sanitation systems. 7/28/2024 Dr/Mohammed A. Al-Kholani 164  Water Pollution Water Pollution 7/28/2024 Dr/Mohammed A. Al-Kholani 165  Types of water pollution 1- Point pollution source: Point pollution source refers to contaminants that enter a waterway through a single discrete (‫ )منفرد‬path, such as a pipe or ditch )‫)قناة –خندق‬, or leakage from a ship. 2- Nonpoint source pollution: Nonpoint source pollution is accumulative effect of smallamounts of contaminants gathered from a large area (i.e. leaching out of nitrogen compounds from agricultural land). 7/28/2024 Dr/Mohammed A. Al-Kholani 166  Nonpoint source pollution 7/28/2024 Dr/Mohammed A. Al-Kholani 167  Types of Water Pollutants Water pollutants can be classified as. Biological pollutants Are living organisms or their products include pathogens (such as parasites, bacteria, viruses) or undesirable living organisms Non-biological pollutants Are nonliving hazardous materials, such as chemicals (e.g. Cyanides, Heavy metals, Minerals and Organic acids, Nitrogenous substances, Sulfides, Ammonia) and physical agents 7/28/2024 Dr/Mohammed A. Al-Kholani 168  Causes of water pollution Causes of water pollution Sewage Organic Substances Inorganic substances: Thermal pollution Radioactive material Sewage. The source of most bacterial and viral pathogens in water; release of sewage in water occurs in any underdeveloped sewage plants or leaky sewage collection systems (pipes, pumps, valves). Some cities also have combined sewers, which may discharge untreated sewage during rain storms. 7/28/2024 Dr/Mohammed A. Al-Kholani 169 Causes of water pollution 7/28/2024 Dr/Mohammed A. Al-Kholani 170 Causes of water pollution Organic Substances Detergents, disinfection by products such as chloroform, which forms during chlorination of water, Food processing waste which can include oxygen-demanding substances like fats and grease, thus eating up oxygen content of water, Insecticides and herbicides, petroleum (fuels and lubricants from urban run-off, tree and bush debris “during storms”, Industrial solvents and cosmetic products (face wash, creams, shampoo, etc). 7/28/2024 Dr/Mohammed A. Al-Kholani 171 Causes of water pollution Inorganic substances: Acids (specially sulfur dioxide from power plants), Ammonia , fertilizers containing nitrates and phosphates, heavy metals (from urban run-off and car washes), cement and gravel (stones) in run-off from construction sites, discarded trash, plastic and sullage. 7/28/2024 Dr/Mohammed A. Al-Kholani 172 Causes of water pollution Thermal pollution: Industries that use water as cooling agent release hot water into rivers and seas, endangering the marine life. Radioactive material: With increasing dependence on nuclear power in developed countries, radiation pollution in water has also increased 7/28/2024 Dr/Mohammed A. Al-Kholani 173  Sources of groundwater contamination. 7/28/2024 Dr/Mohammed A. Al-Kholani 174  Indicators of water pollution: 1. Total suspended solids 2. Biochemical oxygen demand at 20°C 3. Absence of dissolved oxygen 4. Chlorides 5. Nitrites and nitrates. 7/28/2024 Dr/Mohammed A. Al-Kholani 175  What can unsafe water cause? (Fig. 5.4) ❑ Globally, 9.1% of disease burden (in DALYs*) and 6.3% of all deaths are directly preventable by improved water safety. ❑ Economically, investment to improve drinking water, sanitation, hygiene and water resource management systems makes strong economic sense. ❑ Every dollar invested leads up-to eight dollars in benefits. a. Infectious diseases ❑ Water residing agents. ❑ Hosts residing in water. b. Others a. Infectious diseases Water residing agents. Poliovirus, Hepatitis A and E virus, Enterovirus, Rotavirus, E. coli, S. typhi, V. cholerae, Giardia, Entamoeba, Ascaris, Chlamydia (that which causes trachoma) and hookworms. *Disability adjusted life years (DALYs); One DALY = 1 lost year of healthy life. DALY7/28/2024 = years lived with disability + years lived shorter than life expectancy Dr/Mohammed A. Al-Kholani 176  What can unsafe water cause? a. Infectious diseases Water residing agents. The burden of water borne diarrhea equals 1.4 million preventable child deaths/year and over long-term, diarrhea/intestinal nematodes stunts the growth of the child and is one of the causative factors of protein energy malnutrition.193 Hosts residing in water. Cyclops (hosts for guinea worm), Mosquitoe (hosts for malaria etc.), Snails (hosts for Schistosoma). Figure 5.4. Diseases contributing to water sanitation and hygiene related burden 194 7/28/2024 Dr/Mohammed A. Al-Kholani 177  What can unsafe water cause? b. Others Fluorosis (caused by excess fluorines), cyanosis (caused by nitrates), arsenic and lead poisoning, buildup (accumulation) of insecticides inside body; regular intake of extremely soft water may cause cardiovascular diseases. 7/28/2024 Dr/Mohammed A. Al-Kholani 178 Biological Pollutants of Water and their Hazards. Waterborne viral agents and the diseases they cause include ▪ Poliomyelitis virus (polio) ▪ Hepatitis A virus (hepatitis). Waterborne bacteria and the diseases they cause include ▪ Escherichia coli (gastroenteritis), ▪ Legionella spp. (legionellosis), ▪ Salmonella typhi (typhoid fever), ▪ Shigella spp. (shigellosis or bacillary dysentery), and ▪ Vibrio cholerae (cholera). Waterborne parasites include ▪ Entamoeba histolytica (amebiasis or amebic dysentery), ▪ Giardia lamblia (giardiasis), and ▪ Cryptosporidium parvum (cryptosporidiosis. Each of these diseases can be serious, and two in particular—typhoid fever and 7/28/2024 Dr/Mohammed A. Al-Kholani 179 cholera—have killed thousands of people in single epidemics Pollutants of Water and their Hazards. Other classification : ▪ Water borne diseases: Viral Hepatitis, Polio, Cholera. ▪ Water based diseases: Schistomiasis , Guiana Worm. ▪ Water related diseases: Malaria, Yellow Fever. ▪ Water washed diseases: Scabies, Dysentery, Conjunctivitis. 7/28/2024 Dr/Mohammed A. Al-Kholani 180  ❖ How can water be purified? A. Nature does its part : B. Artificial: 7/28/2024 Dr/Mohammed A. Al-Kholani 181  ❖ How can water be purified? A. Nature does its part : Rivers dilute the polluted water, the evaporation condensation cycle robs water of its pollutants, aeration and oxidation by sunlight kills many bacteria, storage and sedimentation in ponds removes the particles, UV ray from sunlight is bactericidal. 7/28/2024 Dr/Mohammed A. Al-Kholani 182 ❖ How can water be purified? B. Artificial: The fundamental methods applicable to all water purification systems are distillation and condensation, sedimentation (gravity dependent separation of insoluble particles), coagulation (separation of soluble particles by turning them insoluble by a chemical agent), aeration, adsorption (into the surface of a porous material), filtration (through a sieve ‫)منخل‬ and disinfection (killing pathogens). 7/28/2024 Dr/Mohammed A. Al-Kholani 183 7/28/2024 Dr/Mohammed A. Al-Kholani 184 ❖ How can water be purified? o Large Scale (Measure)Purification: The aim is to provide safe and healthy water – thus ground water (specially) from deep wells, need no treatment. but surface water needs some cleansing. 1. Storage; 2. Filtration; 3. Disinfection 1. Storage: sediments most particles, allows dissolved oxygen is used by aerobic bacteria to destroy most organic matter, and also the bacterial count itself drops by 90% in one week. but long-term storage may cause algal growth. 2. Filtration: This means passing water through small slits, literally. two kinds of filters are in use: 7/28/2024 Dr/Mohammed A. Al-Kholani 185 ❖ Difference between slow sand filter and rapid sand filter 7/28/2024 Dr/Mohammed A. Al-Kholani 186  Elements common to sand filters 7/28/2024 Dr/Mohammed A. Al-Kholani 187  ❖ How can water be purified? Large Scale Purification: 3. Disinfection: An ideal disinfectant for water is that which is Capable of destroying the pathogens in a short contact Removes taste /odor/color producing agents Easily detectable Leaves some residue Nontoxic. In water works, disinfection is synonymous with chlorination (Ozone can be used as it causes no odor and smell, but to its disadvantage, has no residual amount). Chlorine removes bacteria (but not spores) and many viruses (except poliovirus, hepatitis virus), parasites (except their ova); oxidizes iron, Mn and H2S; destroys some taste and odor producing compounds, destroys 7/28/2024 algae and slime Dr/Mohammed A. Al-Kholani 188  References Sanyal P (2015).Community Medicine: A Students Manual. First Edition. New Delhi, London, Philadelphia, Panama. The Health Sciences Publisher. Thank you 7/28/2024 Dr. Mohammed Al-Kholani  Public health FOOD SAFETY Dr. Mohammed Al-Kholani 2022-2023  Food contamination Contaminated food pose a more serious health problem :- Food may contain harmful ▪ bacteria such as salmonella, staphylococcus aureus.ect ▪ viral food transmission is rare. Food may be contaminated by chemical substance like ▪ pesticides, herbicides , and ▪ mercury (Hg) in fish that live in polluted water Cross-contamination It is the contamination of a food product from another source. There are three main ways cross-contamination can occur: ▪ Food to food ▪ People to food ▪ Equipment to food.  Food contamination Cross-contamination : Food to Food ▪ Food can become contaminated by bacteria from other foods. ▪ This type is especially dangerous if raw foods come into contact with cooked foods. ▪ Examples - In a refrigerator, meat drippings from raw meat stored on a top shelf might drip onto cooked vegetables placed on lower shelf. Cross-contamination: People to food ▪ People can also be a source contamination to foods. ▪ Some examples are: - Handling foods after using the toilet without first properly washing your hands. - Touching raw meats and then preparing vegetables without washing hands between tasks. - Using an apron to wipe your hands between handling different foods, or wiping a counter with a towel and then using it to dry your hands.  FOOD POISONING Food poisoning is an acute gastroenteritis caused by many bacteria/ toxins/ chemicals (fertilizers/ pesticides, Cd. Hg)/ vegetable or animal poisons in contaminated food or drink. Foodborne illnesses (food poisoning) can be divided into two types: ▪ Food infection, Type of food poisoning in which living organisms are consumed. ▪ Intoxication (bacterial), Food poisoning caused by bacterial toxin Foodborne transmission, Spread of pathogenic microorganisms in or on foods that are poorly processed, undercooked, or improperly refrigerated  FOOD POISONING Intoxication associated with the ingestion of preformed microbial toxins. It is not an infection. Since the toxins are ingested preformed and no microbial growth within the body is required, the incubation times are very short (within 2–12 h) and there is no fever. Table 9.14. Agents causing food poisoning Table 9.14. Agents causing food poisoning Acute bacterial gastroenteritis ( Food poisoning) (bacterial food poisoning)  Food hygiene All the conditions that must be met during production, processing, storage, distribution of food so that it remains safe, wholesome and fit for human consumption [WHO]. Household hygiene of cooked food The UK Food Standards Agency publishes recommendations as part of its Hazard Analysis and Critical Control Points (HACCP) program. -Cooking food until the CORE TEMPERATURE is 75 °C or above will ensure that harmful bacteria are destroyed. -However, lower cooking temperatures are acceptable provided that the core temperature is maintained for a specified period of time as follows, ▪ 60°C for a minimum of 45 minutes ▪ 65°C for a minimum of 10 minutes ▪ 70°C for a minimum of 2 minutes. Cooked food should be kept in a shelf (and not covered by thin nets).  Milk hygiene Sources of infection: Dairy animal, human handler. Milk borne diseases 1. Zooanthroposes-Brucellosis, tuberculosis, salmonellosis, Q fever, streptococcal infections. 2. Infections from human that are transmitted, via milk-Typhoid, paratyphoid, cholera, viral hepatitis, diphtheria, E coli infection. Prevention 1. Pasteurization of milk 2. Healthy and clean animals 3. Sanitary premises of dairy 4. Sterile vessels to keep milk 5. Safe water supply in the dairy 6. Personal hygiene of milk handlers.  Golden rules for safe food preparation To prevent and control food borne disease (WHO ): 1. Cook food thoroughly. 2. Eat cooked food immediately. 3. Store cooked foods carefully. 4. Reheat cooked foods thoroughly. 5. Avoid contamination between row foods and cooked foods 6. Wash hand repeatedly. 7. Keep all kitchen surface meticulously clean 8. Protect food from insect ,rodent, and other animals. 9. Use pure water.  Thank you References ❑ Talaro KP, Chess B. Foundations In Microbiology. 8th ed, McGraw-Hill Companies, Inc., 2012 ❑ Forbes BA., Sahm DF., Weissfeld AS. , BAILEY & SCOTT’S DIAGNOSTIC MICROBIOLOGY, 12th Ed, Mosby Elsevier, 2007 ❑ Sanyal P (2015).Community Medicine: A Students Manual. First Edition. New Delhi, London, Philadelphia, Panama. The Health Sciences Publisher  Public health CHEMICAL HAZARDS ❑Chemical Hazards ❑Smoking and health Dr/ Mohammed A. Al-Kholani  Public health CHEMICAL HAZARDS ❑Chemical Hazards? Dr/ Mohammed A. Al-Kholan SMOKING AND HEALTH Tobacco -Composition. Carcinogens Tobacco dependance. Teenage age With developing maturity Primary prevention measures  Smoking and health Tobacco was introduced to Europe from South America in the 16th century. → Although its potential for harm was recognized early, → its use was taken up avidly by every society that met it.290 Composition. Of about 500 compounds in tobacco, the most active are nicotine (acute effect) and tars (chronic effect). → Smoke of cigarettes ▪ is alkaline and is completely ionized in the alkaline pH of mouth, ▪ thus not absorbed from mouth. → For effective absorption, it must be inhaled. ▪ However, smoke of cigars and pipes is alkaline, so that they can be absorbed directly from oral mucosa rather than inhalation. ▪ Thus pipe and cigar smokers are more at risk or oral cancer, but less of lung cancer. Smoking and health Carcinogens The major carcinogens in smoke are Polycyclic hydrocarbons, N-nitroso compounds and tars. ? bidis have a higher content of carcinogens than cigarettes. Tobacco dependance. Psychoanalysts, in their characteristic approach of any problem, have attributed cigarette smoking to libido. 'Getting something orally', one asserts... 'is the first great libidinous experience in life'; first the breast, then the bottle, then the comforter, then food and finally the cigarette. -Scott R B, BMJ 1957; 1: 671 Smoking and health Teenage age → Initially teenage boys begin to smoke because of psychosocial reasons (selfesteem and status need), → but quickly the reason becomes pharmacological. With developing maturity → the social demand reduces (the person wants to quit/leave smoking) → but pharmacological demand rises (he cannot quit because of intense withdrawal/ removal reactions). → He can, unfortunately, develop into a 'chain ‫ مكبل‬smoker' whose only objective is to maintain a steady plasma nicotine (t1/2 = 2 hrs) concentration. Smoking and health Primary prevention measures Stopping or avoiding (early) the smoking or chewing tobacco is one of the primary prevention measures of several diseases such as. ❑ Smoking is the first most frequent cause of lung cancer. ❑ Oral cancer is almost exclusively caused by chewing tobacco, in synergism with alcohol, and smoking bidis ,. Unfortunately, most of our lower classes (mostly men and some women) are addicted to one or more forms of chewed tobacco (khaini, nassi, paan). ❑ In the ideal geriatric health services, avoid smoking/alcohol is one of the key primary prevention measures, that aim to promote and maintain the health. Smoking and health Primary prevention measures Stopping or avoiding (early) the smoking or chewing tobacco is one of the primary prevention measures of several diseases such as.. ❑ Cardiovascular diseases, → Behavioral risk factors are responsible for about 80% of coronary heart disease and cerebrovascular disease. Over 300 risk factors have been associated with coronary heart disease and stroke. However, the Most risk factors that are planted included the smoking and alcohol in adolescence.. → Smoking is the third major modifiable risk factors for CVDs, after hypertension and dyslipidemia, respectively.  Public health MICROBIAL HAZARDS ❑Microbial Hazards? ❑Biosafety levels? Dr/ Mohammed A. Al-Kholan ❑Microbial Hazards? ❑Biosafety levels? Acquired hospital infection (AHI) (Nosocomial infections) Dr. Mohammed Al-Kholani 2022-2023  Acquired hospital infection (AHI) (Nosocomial infections) Nosocomial infections and nosocomial diseases are acquired by patients or workers in health care facilities: ❑ Nosocomial infections-Patients are New infections other than the existing disease Acquired after 2 days of the stay in the hospital Except wound infections. Acquired hospital infection (Nosocomial infections) ❑Most nosocomial infections become clinically apparent while patients are still hospitalized; however, disease onset can occur after patients have been discharged. ❑ Infections that are incubating when patients are admitted to a hospital are not nosocomial; they are community acquired. ❑Nosocomial infections may also affect medical care staff and people visiting the patient  Acquired hospital infection Source Nosocomial infections --May be ▪ Exogenous (acquired from the health care environment), ▪ Endogenous (derived from Normal Flora that become opportunistic while in the hospital setting), or ▪ Iatrogenic*: induced by treatment or medical procedures. such as ❑ the use of catheters, ❑ invasive diagnostic procedures, and ❑ surgery *More interventions you try on the patient (catheters, IV cannulas, intubation, general anesthesia) – more the risk of infection. Acquired hospital infection Super infections. May result from the use of antimicrobial drugs that, by inhibiting some resident NF, allow others to thrive (grow well) in the absence of competition. For instance, long-term antimicrobial therapy to inhibit a bacterial infection may allow Clostridium difficile , a transient microbe of the colon, to grow excessively and cause a painful condition called pseudomembranous colitis. Common Types of Hospital Infections include: Wound infections Urinary tract infections Respiratory infections- Pneumonia Skin infections Bacteraemia and septicaemia Gastrointestinal infections. Acquired hospital infection Acquired hospital infection Modes of Spread Various modes of spread of nosocomial infections are: a. Airborne b. Infection by contact c. Infections acquired from food d. Infections associated with water e. From hospital equipment f. Infections by inoculation. Acquired hospital infection (AHIs) Factors Influencing Nosocomial Infections AHIs arise from the interaction of several factors in the health care environment: ❑ Exposure to numerous pathogens present in the health care setting, including many that are resistant to antimicrobial agents ❑ The weakened immune systems of patients who are ill, making them more susceptible to opportunistic pathogens ❑ Transmission of pathogens among patients and health care workers— from staff and visitors, to patients, and even from one patient to another via activities of staff members (including invasive procedures and other iatrogenic factors) Although nosocomial infections can result from any one of the factors shown, most nosocomial infections are the product of the interaction of all three factors. Acquired hospital infection Control of Nosocomial Infections Aggressive control measures can noticeably reduce the incidence of nosocomial infections. These include ❑ Disinfection ; ❑ Medical asepsis, including good housekeeping (cleaning), hand washing, bathing, sanitary handling of food, proper hygiene, and ❑ Precautionary measures to avoid the spread of pathogens among patients; ❑ Surgical asepsis and ❑ Sterile procedures, including thorough cleansing of the surgical field, use of sterile instruments, and use of sterile gloves, gowns, caps, and masks; ❑ Isolation of particularly contagious or susceptible patients; and ❑ Establishment of a nosocomial infection control committee charged with surveillance of nosocomial diseases and review of control measures. Acquired hospital infection Control of Nosocomial Infections Nosocomial infections are usually the ‘resistant’ type and it is best to avoid them by: 1. Isolation of contagious patients, barrier nursing. 2. Placing invasive devices only on need and remove such promptly. 3. Limit surgical antimicrobial prophylaxis (to stop development of excessive resistance); use narrow spectrum antimicrobials for known pathogens. 4. ' Universal precautions' Acquired hospital infection Control of Nosocomial Infections Universal precautions Figure 2. Universal precautions Acquired hospital infection How to wash your hands298 (Fig. 3) A regular soap or alcohol based hand rub will do a satisfactory job. Washing your hands properly takes about as long as singing "Happy Birthday" twice. Figure 3. Proper hand washing  Thank you References ❑ Talaro KP, Chess B. Foundations In Microbiology. 8th ed, McGraw-Hill Companies, Inc., 2012 ❑ Forbes BA., Sahm DF., Weissfeld AS. , BAILEY & SCOTT’S DIAGNOSTIC MICROBIOLOGY, 12th Ed, Mosby Elsevier, 2007 ❑ Sanyal P (2015).Community Medicine: A Students Manual. First Edition. New Delhi, London, Philadelphia, Panama. The Health Sciences Publisher  WASTE DISPOSAL Liquid waste –Hospital waste disposal Dr. Mohammed Al-Kholani 2022-2023 Liquid wastes 1. Industrial liquid should ideally be treated and detoxified before any contact with groundwater or any water source )rivers) 2. Sullage : is the water from bathroom and kitchen, and is usually free of major pathogens, and thus can be allowed to drain into groundwater. 3. Sewage : is the water from latrine which is teeming with pathogens and should NEVER come in contact with any natural source of drinking water; treatment of sewage is a major investment for long – term well-being. Hospital waste disposal Disinfection → disposal →drainage Health care waste is generated by health care establishment ,research facilities from various activities. They may be: 1. General wastes. 2. Hazardous wastes— Infectious material*, genotoxic material (mutagen/teratogen/ carcinogen) and sharp wastes (which may puncture skin;) All bags/bins/trolleys and vats containing hazardous waste should be marked with the biohazard symbol *All materials contaminated with potentially infectious agents must be decontaminated before disposal. Categories of health care waste 1. Human anatomical waste (i.e placenta) 2. Microbiology and biotech waste 3. Waste sharp 4. Discarded medicine, cytotoxic drugs 5. Soiled waste 6. Solid (casts, drip tubes, catheter) 7. Liquid waste (disinfectants) 8. Incineration ash 9. Chemical waste Impact of health care waste Health hazards 1. Infections (especially hepatitis B and C, HIV) 2. Toxic waste )drugs, disinfectants) may get inhaled or come in contact with skin if not properly disposed 3. Radioactive waste(from radiotherapy departments) may get into environments Environmental hazard Hospital waste, a part from looking foul and unsightly, clogs drains ( because of its high polymer content), suffices as a vector breeding place, contaminates ground water and volatile compounds (many drugs and disinfectants) get into the air. Principles of waste management 1. Minimize amount of waste; try reusing old items (with repeated sterilization) instead of demanding new ones 2. Segregate wastes at time of generation into anatomical, infectious non-sharp and sharp waste 3. Disinfect infectious waste before disposal. Population at risk 1. Health care staff (doctors, nurses, auxiliaries) 2. Hospital maintenance personnel 3. Patients and visitors 4. Hospital support service 5. Waste disposal workers 6. General public in vicinity. Which class of waste is to be put in which colors of bags and bins? [a] Placenta should be stored, for extraction of hormones, wherever facilities are available.  Segregation and collection Segregated internal transport The waste is to be carried in dedicated trolleys (black – uncovered, red – covered) to a double chambered vent, located near or inside hospital campus. On site treatment 1. Needles/nozzles to be cut by needle cutter, disinfected by 1% bleach for 1 hr. (but sharps generated in laboratories must stand 10% bleaching overnight) 2. Wet thermal treatment (autoclaving) of reusable biomedical waste. On site segregated disposal 1. Rural/small hospital → landfill 2. Large hospitals → store in double chambered vat near exit 3. Liquid wastes → Neutralize in acid/alkali and drop in septic tank. Off-site segregated transport Daily final disposal in dedicated ,covered vehicles. Off-site disposal 1. Incineration—Not suitable for plastics, silver salts, reactive chemical wastes, ampoules and waste with heavy metals (batteries, thermometers, lead). 2. Chemical disinfection—Suitable for microbial culture media and sharp wastes. 3. Wet thermal treatment (autoclaving)—For all reusable waste except sharp ones. 4. Dry thermal treatment—Dehydrates most biological waste and thus makes them shrink; not suitable for cytotoxic or radioactive waste. 5. Microwave irradiation—For disinfection of reusable waste. 6. Landfill. 7. Inertisation (mixing with cement).  Disposal of Hazardous Waste. Figure 4-6 Autoclave bags. (Courtesy Allegiance Healthcare Corp., McGaw Park, Ill.)  References Sanyal P (2015).Community Medicine: A Students Manual. First Edition. New Delhi, London, Philadelphia, Panama. The Health Sciences Publisher CDC (2012).Principles of Epidemiology in Public Health Practice. Third Edition. Centers for Disease Control and Prevention (CDC) Forbes BA., Sahm DF., Weissfeld AS. (2007). BAILEY & SCOTT’S DIAGNOSTIC MICROBIOLOGY, 12th Ed, Mosby Elsevier,. 28 July 2024 236  Communicable diseases Non-communicable diseases (NCDs) Dr. Mohammed Al-Kholani 2022-2023 Definitions Communicable diseases A communicable (or infectious) disease is one caused by transmission of a specific pathogenic agent to a susceptible host. Infectious agents may be transmitted to humans either: 􀁸 directly, from other infected humans or animals, or 􀁸 indirectly, through vectors, airborne particles or vehicles. Vectors are insects or other animals that carry the infectious agent from person to person. Vehicles are contaminated objects or elements of the environment (such as clothes, cutlery, water, milk, food, blood, plasma, parenteral solutions or surgical instruments). Source: The source of the micro-organism is usually some host or object from where an the organisms directly carry out into another host Reservoir: Origin of the etiologic agent or location from which they disseminate (e.g., water, food, insects, animals, other humans). It is the host/environment where the agent lives and multiplies, depends primarily for survival, and from where it reproduces Communicable disease Definitions Contagious diseases are those that can be spread (contagious literally means “by touch”) between humans without an intervening vector or vehicle. → Malaria is therefore a communicable but not a contagious disease, → while measles and syphilis are both communicable and contagious. → Some pathogens cause disease not only through infection but through the toxic effect of chemical compounds that these produce. For example, Staphylococcus aureus is a bacteria that can infect humans directly, but staphylococcal food poisoning is caused by ingestion of food contaminated with a toxin that the bacteria produces.  communicable disease Sources of Infection The primary source of infection is defined as the location at which the pathogen is present and reproduces. The Secondary sources of infection are inanimate objects, materials, or third persons contributing to transmission of pathogens from the primary source to predisposed persons Communicable disease Transmission Pathways of Pathogenic Microorganisms  Carriers: Role of carriers in transmission of infectious agents. carriers Figure 13.17 Involvement of carriers in transmission of infectious agents. (a) An asymptomatic carrier is infected without symptoms. (b) Incubation, convalescent, and chronic carriers can transmit the infection either before or after the period of symptoms. (c) A passive carrier is contaminated but not infected and spreads the pathogen through physical contact. Box 7.1. Global burden of communicable disease ❑ Communicable diseases account for 14.2 million deaths each year (Figure 7.1). ❑ Another 3.3 million deaths are attributable to maternal and perinatal conditions and nutritional deficiencies. Together these account for 30% of the world’s deaths and 39% of the global burden of disability.1 ❑ Six causes account for almost half of all premature deaths, mostly in children and young adults, and account for almost 80% of all deaths from infectious diseases: 􀁸 Acute respiratory infections (3.76 million) 􀁸 HIV/AIDS (2.8 million) 􀁸 Diarrhoeal diseases (1.7 million) 􀁸 Tuberculosis (1.6 million) 􀁸 Malaria (1 million) 􀁸 Measles (0.8 million) Most of these deaths occur in low-income countries. WHO projections suggest that – due to better prevention – total deaths from these causes will decline by 3% over the next 10 years. communicable disease Figure 7.1. Projected main causes of death worldwide, all ages, 2005: total deaths 58 million1  Non-communicable diseases (NCDs) NCDs differ from communicable disease in few important points, 1. They are non-communicable. 2. They do not have a defined incubation period—Chickenpox has an incubation period between 7–21 days, but we can never tell when a person affected with insulin resistance will begin to show features of Type II diabetes. 3. Agents are vague (multifactorial causation)—We can safely say that a certain herpes virus (varicella zoster virus) causes chickenpox, but we are not exactly sure what, if anyone agent, causes diabetes. 4. Natural history if often uncertain/unpredictable—Most infectious diseases follow a certain pattern of clinical presentation (i.e. chickenpox shows up as polymorphic vesicles spreading centrifugally, along with fever; but there are a numerous of ways in which diabetes can present.  Non-communicable diseases (NCDs) NCDs differ from communicable disease in few important points, 5. The boundary between diseased and non-diseased is very blurry —One either has or does not have chickenpox, but regarding diabetes, one can have anyone of obesity, metabolic syndrome, impaired fasting glucose, impaired glucose tolerance, insulin resistance OR frank diabetes; it's hard to say at exactly what point of time someone acquires diabetes. 6. Slowly progressive—Barring some exceptions (i.e. leprosy), most infectious diseases have rapid progress which results in either death or complete cure; but diabetes won't kill you quickly, it will slowly gnaw at your eyes, nerves and blood vessels.  Non-communicable diseases (NCDs) NCDs differ from communicable disease in few important points, 7. Usually nonreversible and permanent pathology—Infectious diseases are the only 'curable' diseases in the trust sense of the word, most non-communicable diseases are not. 8. Leave some residual disability and rehabilitation is necessary—Most communicable diseases (except some like leprosy) can be completely cleared from the body, but not diabetes, which will usually produce some disability (blindness, stroke and residual weakness) over long term. 9. Definite lag period between behavioral change and disease progression—There is a certain gap between change of food habits (eating refined carbohydrates and fats) and development of Type II diabetes.  Non-communicable diseases (NCDs) PROBLEM ( Factors affect NCDs) Previous, a problem of developed nations, NCDs are rising in developing countries due to 1. Demographic transition (greater life expectancy). 2. Medical transition (most people now survive a single myocardial infarction, to suffer from a second). 3. Risk transition/ changing (we are acquiring all the bad habits of the west). Box 6.1. Chronic disease epidemiology: Chronic diseases are the major cause of death in almost all countries and account for 36 million deaths each year (see Figure 7.1). This translates to 61% of the world’s deaths and 48% of the global burden of disease. 20% of chronic non-communicable disease deaths occur in high- income countries, and 80% occur in low- and middle-income countries – where most of the world’s population live. The leading chronic diseases are: ❑cardiovascular disease (CVD), especially coronary heart disease and stroke (17.5 million deaths); ❑cancer (7.5 million deaths); ❑chronic respiratory disease (4 million deaths); and ❑diabetes (1.1 million deaths). Regional estimates indicate that chronic diseases are more frequent causes of death than communicable diseases worldwide, with the exception of the African region. Figure 7.1. Projected Figure 7.1. Projected main causes of death main worldwide, allofages, causes death worldwide, all ages, 2005: total deaths 58 2005: total million1 deaths 58 million1  Thank you References ❑ Bonita R, Beaglehole R, Kjellström T. Basic epidemiology /. 2nd edition. World Health Organization 2006 ❑ Talaro KP, Chess B. Foundations In Microbiology. 8th ed, McGraw-Hill Companies, Inc., 2012 ❑ Sanyal P (2015).Community Medicine: A Students Manual. First Edition. New Delhi, London, Philadelphia, Panama. The Health Sciences Publisher