Microorganism that cause disease

1. Microorganism that cause disease A child being vaccinated for smallpox in the great last smallpox worldwide vaccination by WHO and UNICEF

2. Introduction to Human pathogens • We normally think of pathogens in hostile terms—as invaders that attack our bodies. But a pathogen or a parasite, like any other organism, is simply trying to live and procreate. Living at the expense of a host organism is a very attractive strategy, and it is possible that every living organism on earth is subject to some type of infection or parasitism. • A human host is a nutrient-rich, warm, and moist environment, which remains at a uniform temperature and constantly renews itself. It is not surprising that many microorganisms have evolved the ability to survive and reproduce in this desirable niche. • There are several types of human based pathogens that are re classified by microbiologists and health care professionals , they are mostly categorized according to the disease they cause and how the spread as well as what kind of pathogen causes them.

3. Types f Pathogens The types of microorganisms that cause disease Diagram 1: Different types of infections b a • The physical type of microorganisms is important in understanding how the disease spreads and how to treat it . • They are broken up into : • Paracital • These are microscopic Animalia like worms and others • Examples: malaria and biliary • Bacterial • These are infections spread by bacteria • Examples: E.coli and Gonorrhea • Viral • Infections caused by viruses • Examples: HIV and Chicken pox • Fungal • Infections caused by fungi • Examples: Athlete’s foot and Ring worm c d As Above: a. P. falciparum or malaria in blood cells under an electron microscope; b. Gonorrhea neisseria infecting a baby’s eyes; c. Chicken pox infection; d. A standard case of athlete’s foot

4. Way diseases spread Ways in which disease spread Diagram 2: Summary of basic ways diseases spread • There are 2 categories that disease spread: • Direct • Involves the direct contact with the contagion or ill person or environmental factor that is contaminated • Indirectly • Contact with a person, animal or environmental factor that is not infected but a carrier of the microorganism that can cause disease • Most dangerous form of diseases as these spread rapidly Direct Indirect

5. Way diseases spread 1) Direct spread 2) Indirect spread Zoonotic diseases: Vector born: When a pathogen can replicate and spread fro the normal activity of the animal and often does not cause disease in the animal but is not necessary for pathogen’s survival Insect bites E.g. Malaria and Rabies Reservoir born: When a pathogen is naturally found in the animal and needs to live here to survive Animal-Human contact E.g. Salmonella on snake skin and West Nile Virus in water birds Environment born: These are pathogens that spread through the environment (air or water born diseases); often due to poor hygiene or sterilization methods. Eg. Typhoid fever and E.coli infections Hospital acquired infections: due to the presence of a high volumes of sick people the infections spread through contact to infected equipment E.g. Pseudomonas infections and resistant strain TB • Contagious Disease • Also known as Person-to-person spread • This is the spread of diseases through the contact of a person to another person, e.g. sexually transmitted diseases or kissing • E.g. HIV and Bronchitis • Infectious Disease • A group of infections but in direct contact it is only Droplet spread • This is the exposure of a person to droplets of bodily fluids that have been expelled from a ill person e.g. coughing and sneezing directly onto a person • E.g. Flu and Chicken pox

6. Prevention of Disease 1) Introduction to prevention Diagram 4: Correct method for sneezing and coughing (Vampire sneeze) • Vaccines: • This is an injection or oral medication given to masses to prevent disease especially protection against viral infections • The most well known and effective vaccine is the smallpox vaccine which irradiated small pox by the end of the 1970’s • Sterilization • Applied to food and beverage industry and in the health industry , this is the complete irradiation of any microbial infectants or contaminants • E.g. of methods of sterilization: Chemical sterilization, Dry heat Sterilization, Wet heat sterilization , Irradiation and Pasteurization • Good hygiene practice • Should be applied by every single person but especially the immunocompromised (HIV and Cancer patients and diabetics) • Methods such as washing hands correctly and not sharing personal hygiene items like toothbrushes

7. Antimicrobials 1) Introduction 2) Supplements that aid treatment Folic acid Helps treat bacterial infections as it interrupts the bacteria's ability to absorb iron (important for bacteria growth) Vitamin C Increases the bodies immune system reactions Cranberry Extracts Prevents adhesion of bacteria (specifically E.coli) to the lining of the bladder and urinary tract in urinary infections Probiotics Encourage growth f good bacteria in the body to restrict growth of pathogens Immune boosters Although not always a good idea, some help boost the immune system and fight the infection before it infects the blood (septisimia) • Antibiotics • An antimicrobial used for bacterial infections , they are prescribed according to the type, severity and strain of bacteria that has infected the patient • The most well known is penicillin discovered by Alexander Fleming, it is not used anymore as many bacteria have developed resistance over the years to it. • Antivirals • Antimicrobial that is used to treat viral infections , tests must be performed to see at what stage of infection it is before treatment commenseas they work at different levels and stages of infection • The most well known antiviral is the antiretroviral used to treat HIV • Antifungals • Antimicrobials that are used to treat fugal infections , they are normally injectable or a topical cream as fungal infections are the easiest infections to treat • A well known one is Neosporin , a topical treatment for ringworm and athlete’s foot • General antimicrobials • Used to treat infections caused by parasites and other various infections

8. Important Diseases 1) HIV and AIDS Diagram 3: Photograph of a patients with untreated HIV/AIDS Top: Malnutrition HIV inflicted patient Bottom pictures: Depicts Kaposi lesions that develop as a symptom of untreated HIV / AIDS • Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency syndrome (AIDS) is rumored to have started as an accidental zoonotic disease that modified into a person-to-person infection • It affects the immune system by “disguising itself” as a specific type of white blood cell , eventually completely killing off the white blood cells leading to AIDS • It is spread through contact of any contaminated liquid , most commonly through blood-wound contact and unprotected sexual intercourse • Symptoms: Flu like symptoms , increase in intensity and prevalence to other infections and common Kaposi lesions in untreated patients • Treatment: Antiretroviral Treatment (ARV’s)

9. Important Diseases 2) Tuberculosis Diagram 4: Diagnosis techniques of patients with tuberculosis a a- skin allergen test b- X-rays of the chest show scar tissue formed by the infection in the lungs c- Laboratory tests are done on patients with TB in suspected resistance cases and when infection is in another part of the body • Tuberculosis is cause by a bacteria called Mycobacterium tuberculosis. • It is highly contagious and infectious disease that infects all the systems in the body but is commonly known to infect the respiratory system • A fairly new strain called XDR TB is highly contagious and is resistant to the common treatment of TB • Respiratory tuberculosis symptoms: • Weight loss, loss of appetite , night sweats , persistent cough, tiredness, and coughing up blood • Treatment: • 4-drug regimen: isoniazid, rifampin, pyrazinamide, and either ethambutol or streptomycin is given to patients with initial or enteric infections (first and only infection) • Reoccurring TB is treated with streptomycin b c

10. Important Diseases 3) Malaria Diagram 5: The life cycle of Plasmodium spp. • This is a disease caused by a parasite (Plasmodium spp.) that infects the blood and is primarily a zoonotic disease spread by mosquitos • It has the highest incident rates in areas where there is poor medical treatment or access to medical or prevention systems • Symptoms: • Vomiting , diarrhea , headaches, fever , sweating, shaking chills • Treatment: • Chloroquine (oral for all except P.falciparum) • Intravenous infusion for P.falciparuminfections • Prevention: • Pest control : mosquito nets , pesticides and eradication of stagnant water • Antimalarial drugs: Chemoprophylaxis • Bite prevention

11. Microorganisms important in medicine Beneficial aspects in medicine Diagram 6: The Penicillin growing on agar that Alexander Fleming discovered • Microorganisms , especially bacteria are important in producing biological compounds that cannot be made in a laboratory. • Examples: • Penicillin • Discovered by Alexander Fleming , it is produced by Penicillium notatum • Was noted that it had killed microorganisms growing on an agar plate with it • Streptomycin • Discovered as effective treatment for TB • Produced by Streptomyces griseus. • Insulin • At the beginning of the “Genetic era” scientists discovered recombinant DNA modification that allowed scientists to modify yeast cells to produce human insulin • Up until then , insulin was taken from sheep and bottled for diabetics

12. Testing surfaces and disinfectants Description Diagram 5: Example of expected results • Coliform and Enterobacteriaceae bacteria are known for causing contagious bacteria gastrointestinal infections , these bacteria can be grown on MacConkey Agar • Surfaces that we often need to be clean are easily contaminated , it is important to see if it is clean or not • It is also important to see if the cleaning agents we use to clean surfaces are as effective as they claim. Top image: hand imprint on Blood agar Bottom image: Disinfectants tested on inoculated agar

13. Key words