Infection Control

Causes and Spread of infection

Q 1.1 - Identify the differences between: bacteria, viruses, fungi and parasites.

* Bacteria are unicellular, prokaryotic microorganism found almost in all kinds of habits. Some bacteria are beneficial like those involved in nitrogen fixation and some pathogenic, which cause diseases. * Viruses are unicellular, tiny organisms which is mostly composed of DNA (DeoxyriboNucleic Acid) and protein. Its body compromises of head and tail sections. Viruses attach themselves to other organisms and cause severe infectious diseases. * Fungi are a group of simple plants whose cells are devoid of chlorophyll. Fungus has chitis in its cell walls instead of cellulose. Fungi are popular for beneficial effects including food production, penicillin production and decomposition. * Parasites are those micro-organisms which depend on other organisms (hosts) for their survival. Both virus and bacteria could be parasites.

Q 1.2 - Identify common illness and infections caused by: bacteria, viruses, fungi and parasites.

* Common illness and infections caused by bacteria are:-

- Impetigo. - Salmonella. - Tuberculosis (TB). - Cholera. - Anthrax. - Shigella. - Pertussis (Whooping Cough). - Bubonic Plague. - Leprosy. * Common illness and infections caused by viruses are:- - Aids / HIV. - Hepatitis. - Polio. - Cold. - Chicken Pox. * Common illness and infections caused by fungi are:- - Thrush. - Ringworm. - Anthrax. - Athlete’s Foot. * Common illness and infections caused by parasites are:- - Diarrhea. - Pneumonia. - Meningitis.

Q 1.3 - Describe what is meant by infection and colonization. * The definition of Infection is: the growth of a parasitic organism (a parasitic organism is one that lives on or in another organism and draws its nourishment there from), within the body. A person with an infection has another organism (a germ) growing within, drawing its nourishment from the person. The infection has some exceptions, for example the normal growth of the usual bacteria flora in the intestinal tract is not usually considered an infection. The same consideration applies to the bacteria that normally inhabits its mouth * The definition of Colonization is: the presence of bacteria on the body surface, (for example: skin, mouth, intestines or airways) without causing disease to the person. An example of colonization is: - MRSA.

Q 1.4 - Explain what is meant by systemic infection and localized infection. * The definition of Systematic Infection is: an infection that in which the pathogen is distributed throughout the whole body rather than concentrated in one area, for example: . - Strep Throat. - Chronic Fatigue syndrome. - Diabetes Mellitus. - Graves’ Disease (Thyroid disorder). - Rheumatoid Arthritis. - Sickle Cell Disease. * The definition of Localized Infection is : an infectious or neoplastic process that originates in and is confined to a one organ system, or a general area of the body, for example: - A sprained ankle. - A boil on a hand. - An abscess on a finger.

Q 1.5 - Identify poor practices that may lead to the spread of infection. * Poor practices that may lead to the spread of infection, could be: - Poor hygiene (for example: not washing your hands after going to the toilet / before dealing with food or wearing a dirty uniform). - Not wearing the protective clothing provided, (for example not wearing gloves or aprons when assisting with personal care, not wearing a tabard when serving food). - Not covering your mouth or nose when sneezing or coughing. - Sharing infected needles.

Q 2.1 - Explain the conditions needed for the growth of micro- organism * This varies depending on the type of bacteria. For example warm blooded animal pathogenic bacteria requires a temperature of around 98F, a correct entry site and for the host to be susceptible to that type of bacteria. Thermo- phallic bacteria requires extremely hot temperatures to grow. Viruses require a healthy host cell in order to get its DNA / RNA replicated. Parasites require the host’s body to be healthy enough to sustain itself and the parasite.

Q 2.2 - Describe the ways an infective agent might enter the body * The ways an infective agent might enter the body could be :- - Inhalation: infective agents who are airborne enter the body when we breathe. - Ingestion: infective agents can be contained in or on the food we eat. That When we eat and digest the food we digest the infective agent, which then gets into our bloodstream. - Oral, Vaginal or Anal Sexual Transmission: when we have sex without using protection, then infective agents can enter our bodies via sperm and bodily fluid. - Passage to fetus during pregnancy or birth: infective agents can transfer via the umbilical cord. - Wound Contamination: infective agents can transfer into our bloodstream via open wound, which are open to airborne or surface bacteria. - Insect or Animal Bites: The infective agent is transferred to our bodies via the insect or animal injecting their teeth into our skin and feeding on our blood. The infective is then in our bloodstream.

Q 2.3 - Identify common sources of infection * Common sources of infection identified could be:- - Toilets - Kitchens - Personal care - Other individuals

Q 2.4 - Explain how infective agents can be transmitted to a person. * Droplet contact - it is a typical mode of transmission among many infectious agents. If an infected person coughs or sneezes on another person the micro- organisms, suspended in warm moist droplets may enter the body through the nose, mouth or eye surfaces. Diseases that are commonly spread by coughing or sneezing include (but not all of): - Bacterial Meningitis. - Chickenpox... - Common Cold. - Influenza. - Mumps. - Strep Throat. - Tuberculosis (TB). - Measles. - Rubella. - Whooping Cough. * Fecal - Oral Transmission - direct contact is rare in this route, for humans at least. More common are the indirect routes: foodstuffs or water become contaminated (by people not washing their hands before preparing food, or untreated sewage being released into drinking water supply) and the people who eat and drink them become infected. Diseases spread by this transmission are (at least): - Cholera. - Hepatitis A. - Polio. - Rotavirus. - Salmonella. * Sexual Transmission - this refers to any disease that can be caught during sexual activity with another person, including vaginal sex or anal sex or (less commonly) through oral sex. Transmission is either directly between surfaces in contact during intercourse ( the usual route for bacterial infections and those infections cause sores) or from secretions (semen or the fluid by the excited female) which carry infectious agents that get into the partners blood stream through ting tears in the penis, vagina or rectum (this is a more usual route for viruses). In the second case, anal sex is considerably more hazardous since the penis opens more tears in the rectum than the vagina, as the vagina is more elastic and more accommodating. Some diseases transmissible by sexual route include (at least): - HIV/ AIDS. - Chlamydia. - Genital Warts. - Gonorrhea. - Hepatitis B. - Syphilis. - Herpes. * Oral Transmission - Sexually transmitted diseases such as HIV and Hepatitis B are thought not to be normally transmitted though mouth to mouth contact, although it is possible to transmit some STDs between the genitals and the mouth, during oral sex. In the case of HIV this possibility has been established. It is also responsible for the increased incidence of herpes simplex virus 1 (which is usually responsible for oral infections) in genitals infections and the increased incidence of the type 2 virus (more common genitally) in oral infections * Oral Transmission - diseases that are transmitted primarily by oral means may be caught through direct oral contact such as kissing, or by indirect contact such as such as sharing a drinking glass or a cigarette. Diseases that are known to be transmissible by kissing or by other direct or indirect oral contact include all the diseases listed above as transmissible by droplet contact and also (at least): - Cytomegalovirus infections. - Herpes simplex virus (especially HSV-1). - Infectious mononucleosis. (Notice these are all forms of herpes virus). * Transmission by direct contact - diseases that can be transmitted by direct contact are called contagious (contagious is not the same as infectious; although all contagious diseases are infectious, not all diseases are contagious). These diseases can also be transmitted by sharing a towel (where the towel is rubbed vigorously on both bodies) or items of clothing in close contact with the body (for example socks) if they are not washed thoroughly between uses. For this reason, contagious diseases often break out in schools, where towels are shared and personal items of clothing accidentally swapped in the changing rooms. Some diseases that are transmissible by direct contact include: - Athlete’s Foot - Impetigo - Syphilis (on rare occasions, if an uninfected person touches a chancre) - Warts * Transmission by indirect contact - transmissions can also be indirect, via another organism, either a vector (e.g. a mosquito) or an intimidate host (e.g. a tapeworm in pigs can be transmitted to humans who ingest improperly cooked pork). Indirect transmission involves large pathogens like macro parasites with more complex life styles. * Vertical Transmission - this is from mother to child, often in utero or during childbirth (also referred to as prenatal infection). It occurs more rarely via breast milk. Infectious diseases that can be transmitted this way include: - HIV. - Hepatitis B. - Syphilis. * Iatrogenic Transmission - transmission due to medical procedures, such as injections or transplantation of infected material. Some disease that can be transmitted iatrogenically include: - Creutzfeldt-Jakob Disease (CJD) by injection of contaminated human growth hormone. - MRSA infection often acquired as a result of a stay in hospital. * Vector Borne Transmission - a vector is an organism that does not cause disease itself but that transmit infection by conveying pathogens from one host to another. The route of transmission is important to epidemiologists because patterns of contact vary between different populations and different groups of populations depending on socio-economic, cultural and other features (e.g. low personal and food hygiene due to the lack of clean water supply may result in increases transmission of diseases by the fetal-oral route, such as cholera. Differences in incidence of such diseases between different groups can also throw light on the routes of transmission of the disease. For example, if it is noted that polio is more common in cities in undeveloped countries, without clean water supply, than in cities with good plumbing system, we might advance the theory that polio is spread by fecal-oral route.

Q 2.5 - Identify the key factors that will make it more likely that infection will occur. * The key factors that will make it more likely that infection will occur, could be :- - A weak immune system, either due to age or a medical condition. - Eyes, nose, mouth and skin. - Uncovered open cuts and wounds. - No immunization to certain diseases (especially in third world countries). - Sharing infected needles. - Having unprotected sexual activities. - Unhygienic practices when dealing with individuals (not washing hands after assisting with personal and sanitary care). - The use of dirty medical instruments. - Underlying medical conditions and heredity. - Contaminated food and water supplies. - Malnutrition / Obesity.