Bacteria are found everywhere: in soil, water, artic ice, on and within animals and plants. Bacteria can cause damage in two ways: 1) by producing poisons 2) by entering body tissues and growing within them Rickettsias and chlymydias are classified as bacteria, although they are much smaller and exist only within living cells. Fungi are much larger and more complex than bacteria. They are often referred to as yeasts or molds. Familiar forms are mushrooms and the yeasts used to bake bread or brew alcoholic beverages. Diseases caused by fungi are called: myucotic infections. Viruses are the smallest known infectious agents. They are acellular and grow only within living cells. Protozoa are animal-like microbes. There are four main types which include: amebas, ciliates, flagellates, and sporozoa Helminths are parasitic worms that cause infestation.
Impetigo is a fairly common superficial skin infection caused by bacteria. It may occur on normal skin, but the bacteria usually invades at the site of a skin abrasion, scratch, or insect bite. Treatment is with antibiotics. The infection starts as a red sore that blisters briefly and then oozes during the next few days to form a sticky crust. The sore tends to grow and is contagious through bacteria in the blister’s fluid. Physical contact such as scratching can spread the infection to other parts of the body or even to other people. Treatment: Topical medications are effective in minor infections. Extensive infections may require antibiotics such as penicillin.
Tetanus, also known as lockjaw, is caused by bacterial spores that have entered a deep wound. The spores germinate and produce a toxin which interferes with nerves controlling muscles. Progressive muscular spasms result. If muscle spasms develop early and are severe, chances of recovery are poor. Prevention through immunization is the best treatment.
Diphtheria is an acute bacterial infection that usually attacks the respiratory tract. The infection occurs by inhalation of airborne droplets. Signs & symptoms are: sore throat and hoarseness, nasal discharge, malaise and fever, thick gray membrane covering throat & tonsils, a rapid pulse. With proper bed rest and antitoxin, diphtheria prognosis is good. The gray membrane can be dangerous if it obstructs breathing.
Note membrane growing at back of tongue.
Cellulitis usually occurs with dermatitis, a fungal infection, or after a skin injury. It may be accompanied by a fever. Treatment: antibiotics; elevation of infected area; application of hot, moist compresses to site.
Lyme disease was first diagnosed in New Lyme, Connecticut as a rare form of arthritis. It is, however, now known to be a bacterial infection caused by a spirochete that is present in the deer tick. The vector (insect that carries the infection) usually transfers the bacteria by biting a host (human). Signs and symptoms usually include: papule that becomes red, warm, and itchy. The lesion may grow to over 20 inches in diameter; it typically resembles a bull’s eye or target. Malaise and fatigue are constant. There are generally intermittent episodes of headaches, neck stillness, fever, chills, & achiness. Treatment is a 10 to 20-day course of antibiotics.
Due to its small size, the deer tick is often hard to see, making detecting of this vector difficult.
Candida is part of the normal flora of the mouth. It is an opportunistic infection that is usually held in check by other organisms and the immune system. When the immune system is compromised (chemotherapy, long-term illness, transplantation, stress, AIDS, etc.), the infection can occur. Signs: cream-colored patches on tongue, mouth, and/or throat. Treatment is with oral antifungal mouth solution --Nystatin. (“Swish & Swallow)
Candidiasis of the skin is characterized by pruritus (itching) and peeling. This fungal infection usually occurs in damp moist areas. It is often seen in folds of skin. The fungi will spread, producing a fringed irregular edge and pustules. The individual is subject to soreness, itching, and peeling of the lesion. Predisposing factors might include: diabetes, antibiotic therapy, immune deficiency, oral contraceptive use, cytotoxic drug therpay, and obesity. Other common manifestations of skin candidiasis are: diaper rash & vaginitis. Treatment includes topical and/or oral administration of antifungal drugs.
Nail fungi are usually a result of extended exposure to moisture. (e.g. moisture trapped under acrylic nails). Nail beds can become red and swollen. The infected nail is whitish-yellow and tends to be flaky and soft. Purulent discharge may be seen from nail bed. Treatment may include topical and or oral antifungal medication. Sometimes the nail may be removed.
This fungal infection causes hair-like papillae on top of tongue to grow. It produces a condition in which the tongue looks as though it is covered with hair. Hairy tongue is generally an opportunistic infection that occurs when the natural flora of the mouth is not in balance. It can be a result of antibiotic therapy, excessive use of certain mouthwashes, a decrease in saliva flow, or a lack of adequate oral hygiene. Although not serious, hairy tongue looks shocking. Treatment generally involves discontinuation of the offending antibiotic, or mouthwash; remove growths by gently brushing with tooth brush
The white patches seen on skin are due to colonies of fungi which prohibit regular pigmentation. These patches usually have a slightly raised, velvety texture. Treatment includes use of an antifungal sulfur soap which is left on skin overnight for a period of a month. Topical antifungal ointments may help.
“Ringworm” is due to a parasite, not an actual worm. The infestation was named after the characteristic rings seen on the skin. These rings can grow outward as the infection spreads. Ringworm is very contagious and may spread through entire households and from schoolmate to schoolmate. For a mild infection, treatment is an over-the-counter antifungal agent.
Blastomycosis is caused by a yeast-like fungus. Cutaneous blastomyucosis causes nonpruritic lesions on exposed body parts which may become raised and reddened and sometimes necrotic.
Cutaneous blastomycosis lesions can disseminate to bone and cause subcutaneous soft tissue swelling resulting in tenderness and warmth over bony lesions. Treatment with antifungal medication amphotericin B or fluconazol may be used.
Chromomycosis is a slowly spreading fungal infection of the skin and subcutaneous tissues. It can produce granulomatous lesions on the legs or arms and may spread to the brain if not treated. This type of fungal infection requires a systemic antifungal agent. The condition is chronic.
Warts are common, benign viral infections of the skin caused by the human papillomavirus Some warts disappear readily with treatment whereas others necessitate prolonged treatment. Treatment might include: electrodesiccation (effective for common warts), cryotherapy (useful for facial or genital warts), acid therapy (not recommended for areas where perspiration is heavy)
Herpes type I affects skin and mucous membranes. It commonly produces cold sores and fever blisters. Presently, there is no cure for herpes virus. Herpes type II primarily affects the genital area is transmitted by sexual contact. Cross-infection may result from orogenital sex. Treatment with ointment (acyclovir) may be helpful.
Most cases of herpes simples virus (HSV) infection occur when infants are contaminated by the mother’s reproductive tract immediately prior to or during birth. HSV infections can be very destructive to the fetus or newborn and in some cases may be fatal.
Poliomyelitis is an acute communicable disease caused by the poliovirus. Polio can range in severity from inapparent infection to fatal paralysis. The virus can affect the motor nerve cells and cause paralysis to various parts of the body. Only about 10% of infected people develop identifiable symptoms, and researchers report that paralysis probably affects fewer than 1% of those infected with the poliovirus. Polio was first recognized in 1840 when it became an epidemic in Norway and Sweaden. Outbreaks became pandemic and the incidence of infection peaked during the early 1950s. In 1955, Jonas Salk created the polio vaccine which has effectively eliminated poliomyelitis.
The polio virus could cause muscular paralysis to the diaphragm and intercoastal muscles. When this happened, breathing was possible only with the “iron lungs”.
Varicella is an airborne infection. Symptoms include lethargy and raised skin eruptions that are pruritic (itchy). There are three stages of the eruptions: papules, vesicles, & crusted lesions when vesicles have opened. Chickenpox is contagious as long as one has lesions. There is a varicella vaccination which prevents chickenpox. Shingles (herpes zoster) is a condition that can develop in people who have had chickenpox. The virus becomes dormant in nerve cells and may later be stimulated and cause painful skin eruptions along skin supplied by the infected nerve.
Measles is a very contagious viral infection. Transmission of rubella is airborne by way of infected droplets from the nose of mouth. Signs and Symptoms include: high fever, pain of eyes and sensitivity to light. The most characteristic sign is a maculopapular rash (red blotch and tiny bump). Persons are contagious until the rash is gone. Vaccination against rubella is effective.
Mumps is caused by a virus and spread by inhalation of infected droplets. Affected individuals become contagious one day before the symptoms are apparent. Symptoms can include: swollen, painful salivary glands which cause the cheeks to puff out, low-grade fever, & lethargy. Mumps is not a serious disease. It rarely lasts more than two weeks. In rare instances, encephalitis may develop. The mumps vaccine is safe and effective.
Hepatitis may become chronic or severe and result in cirrhosis of the liver and portal hypertension. As a result of portal hypertension, excess fluid seeps from the liver into the abdominal cavity (ascites). Treatment for ascites might includes diuretics, or abdominocentesis.
Leishmaniasis (pronounced lish man-i a-sis) are transmitted when an infected sandfly bites and enters the blood of the host. Leishmaniasis is endemic to most tropical and subtropical countries.
There is a wide geographical distribution of these ”dragon” worms: Asia, Middle East, Arabia, and North and equatorial Africa). Humans are generally infested with this parasite by drinking contaminated water. Once in the human, worms migrate from intestinal tract via subcutaneous tissue to the skin where the fertilized female worms reach maturity and produce juveniles. (Male worms die after fertilization.) Sores produced by reproductive female worms result in a blister. Oftentimes, these sores can be infected with bacteria, resulting in abscesses.
Eventually a superficial blister will ulcerate and the worm is visible. At this point, most infestations are treated by simply removing female worm. Typically, the worm is attached to a small stick and removed by slowly winding the worm on to the stick. Although this is a primitive treatment, it is an effective method. It does not prevent much of the damage caused by worms nor does this method prevent reinfection.
The microscopic larvae of the filarial worm enter the body through the bite of a mosquito or other insect. It tends to infest the lymph nodes and prevent drainage of lymph . This results in swelling and gross disfiguration of genitals and legs. These worms are common in most tropic and subtropic regions. The condition is endemic in Central Africa and Southern South East Asia.
Worm infection is characterized by occlusion of lymph vessels. There is swelling and pain of the limb that is distal to the blockage. After many years the limb may become grotesquely swollen and the skin coarse and tough. Oral medication is available for treatment. The most effective means of preventing filarial infestation is mosquito and insect control.
Treatment for intestinal helminthes generally consists of taking antiparasitic drugs.
The intestinal roundworm, ascaris lumbricoides (as-kah-ris lum-brih-koy-dees), is a giant helminth. The ascaris spends its larval and adult stages in humans. Later, it releases eggs in human feces, which can be spread to other humans through food, drink, or soiled items placed in the mouth. Treatment consists of taking antiparasitic drugs.
The loa loa is a parasitic worm of western and central Africa. It is also be referred to as the “eye worm”. In this picture, the worm is just under the conjunctiva of the eye.
This dangerous tapeworm, Echinococcus granulosus, lives in the intestinal tract of carnivorous animals (e.g. dogs, wolves). Humans become infected from contact with the feces of animals that had eaten flesh of sheep or deer containing the cyst form of the tapeworm. This disease is more commonly seen in people who hunt and trap wild animals or raise livestock.
We are not_alone
We are Not Alone
They are in the air we breathe . . . In our food . . . On our skin . . .
What are microorganisms? (also called microbes)
Microbes are small living plants or animals most of which are not visible to the naked eye. Some microbes cause disease or infection . Many microbes are “good” organisms that help keep balance in the environment and the body.
What microbes lack in size, they make up in number. On the average human, there are about 100 trillion microbes .
Good vs. Bad Microorganisms: Microorganisms that cause disease (germs) are referred to as pathogens . Yeah, I’m bad.
Microorganisms that are harmless or beneficial are called nonpathogens .
Most microbes are considered beneficial or harmless. 87% beneficial organisms 10% opportunists Pathogens 3%
The role of good microorganisms Marine & freshwater microbes form the basis of the food chain in oceans, lakes, and rivers.
Humans and other animals depend on bacteria in their intestines for digestion and synthesis of vitamins including: vitamin B (for metabolism) vitamin K (for blood clotting)
Microorganisms have many commercial applications They are used in synthesis of chemical products such as: acetone enzymes alcohol organic acids many drugs
They are used in the food industry for producing: vinegar pickles cheese green olives alcoholic beverages yogurt bread
Main Classes of Pathogenic Organisms: <ul><li>Bacteria </li></ul><ul><li>simple one-celled organisms </li></ul><ul><li>At home within “climate” of human body </li></ul><ul><li>compose largest group of pathogens </li></ul><ul><li>Fungi: yeasts & molds </li></ul><ul><li>Plant-like organisms that live on dead organic matter </li></ul><ul><li>Grow best in dark, damp places </li></ul>
<ul><li>3) Viruses - smallest microbes </li></ul><ul><li>acellular particles (not a complete cell) </li></ul><ul><li>4) Protozoa </li></ul><ul><li>one-celled animals often found in decayed materials & contaminated water </li></ul><ul><li>5) Helminths </li></ul><ul><li>parasitic worms </li></ul><ul><li>caused by larval & egg infestations </li></ul>
Loa loa being extracted from under conjunctivia.
Hydatid cyst formed by tiny tapeworm that migrated to brain.
<ul><li>Summary </li></ul><ul><li>Microbes are microscopic organisms </li></ul><ul><li>About 100 trillion microbes live on the average human </li></ul><ul><li>“ Bad” microbes are pathogens </li></ul><ul><li>About 3% of microorganisms are pathogenic </li></ul><ul><li>Main classes of pathogenic microbes include: bacteria, fungi, viruses, protoza, & helminths </li></ul>