Unit 5

direct transmission

skin to skin contact. mucous membrane to mucous membrane contact by kissing, sex.

reservoirs (reservoirs of infection)

sources of microorganisms that cause infectious diseases.

measures for prevention and control of epidemics

- Increase host resistance through the development and administration of vaccines that induce active immunity and maintain it in susceptible persons - Ensure that persons exposed to a pathogen are protected against the disease - Segregate, isolate and treat those who have contracted a contagious infection to prevent the spread of the pathogen to others - Identify and control potential reservoirs and vectors of infectious diseases.

10 most notifibale diseases of 2010

1. chlamydia 2. gonorrhea 3. salmonella 4. syphilis 5. HIV 6. lyme 7. pertussis 8. giardiasis 9. streptococcus pneumoniae 10. varicella

largest waterborne epidemic

1993 cryptosporidiosis epidemic of milwaukee.

Tuberculosis (TB)

Lab diagnosis: Acid-fast bacilli, Lowenstein-Jensen or Middlebrook culture media (3 to 6 weeks), Automated and semi-automated instruments, molecular diagnostic procedures, gas-liquid chromatography, susceptibility testing, Delayed hypersensitivity skin test. Treatment: Multiple Abx. Prevention: Vaccine (BCG), Infection control measures.

Typhoid fever (enteric fever)

Lab diagnosis: Culturing, biochemical testing, IDPs. Treatment: Abx, IV fluids, Rehydration. Prevention: Vaccine, Hand washing, Avoid untreated water, Avoid risky foods (raw or fermented foods).

ETEC Diarrhea (Traveler's diarrhea)

Lab diagnosis: Culturing, enterotoxin production, molecular diagnostic procedures, IDPs. Treatment: Self-limiting, Clear liquids, Stay hydrated, Abx. Prevention: Handwashing, Proper food and beverage handling, Avoid street vendors in developing countries, Avoid raw fish, meat and unpasteurized milk, Wash fruits and vegetables.

Gonorrhea

Lab diagnosis: Gram stained specimen in males, Chocolate agar or Thayer-Martin medium, Martin-Lewis medium or Transgrow, ß-lactamase testing, biochemical testing, IDPs. Treatment: Antibiotics, Dual therapy abx. Prevention: No vaginal/anal/oral sex, Condoms, Monogamy.

Streptococcal Pharyngitis (Strep throat)

Lab diagnosis: Rapid strep test and culturing; Bacitracin susceptibility. Treatment: Antibiotics, Anti-inflammatory drugs, Cough drops. Prevention: Proper hygiene; Clean eating/drinking utensils; Cover mouth/nose when cough or sneeze; Don't drink unpasteurized milk.

Mycoplasmal Pneumonia (Primary atypical pneumonia - PAP)

Lab diagnosis: Rise in antibody titer between acute and convalescent sera; Tiny "fried egg" colonies on artificial media Treatment: Abx, Steroids, Immunodulatory therapy, IV immunoglobulin therapy. Prevention: Handwashing, Cover mouth, Annual flu vaccine.

EHEC Diarrhea

Lab diagnosis: Sorbitol-MacConkey agar (culturing), assayed for O157 antigen using commercially available antiserum, IDPs. Treatment: Hydration, Blood transfusion, Dialysis (some cases). Prevention: Cook meats thoroughly, Avoid unpasteurized milk, Avoid contaminated water, Handwashing, Avoid cross contamination.

Cholera

Lab diagnosis: Thiosulfate-citrate-bile-sucrose agar (culturing), biochemical testing, biotyping. Treatment: Rehydration, IV fluids, Abx. Prevention: Improve sanitation, Clean water, Vaccine (cholera), Cooking meat thoroughly.

Plague

Lab diagnosis: Wright-Giemsa stained sputum, CSF or material aspirated from bubo, Gram staining (safety pin), culture, biochemical testing, IDTs. Treatment: Hospitalization, Strong Abx, Isolation. Prevention: Reduce rodent habitat, Insect repellent, Wear gloves when handling dead animals.

Whooping Cough (Pertussis)

Pathogen: Bordetella pertussis. signs: Mild, cold-like symptoms (prodromal, catarrhal); Severe uncontrollable coughing ending in prolonged high-pitched whoop (paroxysmal). Reservoirs: Infected humans.

Lyme Disease

Pathogen: Borrelia burgdorferi. Signs: Bull's eye rash (first stage); Fatigue, chills, fever, headache, stiff neck, muscle pain, joint aches, lymphadenopathy (second stage); Neurological and cardiac problems (third stage). Reservoirs: Ticks, rodents, deer mice, deer.

Genital Chlamydiasis

Pathogen: Chlamydia trachomatis. Signs: Mucopurulent urethral discharge, urethral itching, burning on urination, infertility, proctitis (men). Reservoirs: Infected humans.

Clostridium difficile

Pathogen: Clostridium difficile. Signs: Watery sometimes bloody diarrhea, abdominal cramps, abdominal pain, fever, pus or mucus in stool, nausea, dehydration. Reservoirs: Normal flora (2-3% of healthy non-hospitalized adults).

Tetanus (Lockjaw)

Pathogen: Clostridium tetani. Signs: Painful muscular contractions, spasms, rigid paralysis. Reservoirs: Soil contaminated with human, horse or other animal species, spores introduced into a puncture wound, burn or needlestick contaminated with soil, dust or feces.

Ehrlichiosis

Pathogen: Ehrlichia chaffeensis. Signs: Acute influenza-like illness with fever, headache, generalized malaise. Reservoirs: Unknown.

ETEC Diarrhea (Traveler's diarrhea)

Pathogen: Enterotoxigenic E. coli. Signs: Water diarrhea with/without mucus or blood, vomiting, abdominal cramping, dehydration, low grade fever. Reservoirs: Infected humans. transmission: Fecal-oral route, ingestion of fecally contaminated food or water.

Tularemia (Rabbit Fever)

Pathogen: Francisella tularensis. Signs: Skin ulcer, regional lymphadenitis; Pharyngitis, abdominal pain, diarrhea, vomiting; Pneumonia, septicemia. Reservoirs: Rabbits, muskrats, beavers, some domestic animals, hard ticks.

Bacterial Gastritis and Gastric Ulcers

Pathogen: Helicobacter pylori. Signs: Upper abdominal pain/nausea/heartburn (gastritis); Gnawing, burning, aching, mild to moderate pain below breastbone, empty feeling, hunger (ulcers). Reservoirs: Infected humans.

Legionellosis (Legionnaire's disease, Pontiac fever)

Pathogen: Legionella pneumophila and other L. spp. signs: Anorexia, malaise, myalgia, headache, high fever, chills, dry cough then productive cough, diarrhea, pleural/abdominal pain. Reservoirs: Environmental water sources (ponds, lakes, creeks), hot water systems, air conditioning systems, cooling towers, evaporative condensers, whirlpool spas, hot tubs, shower heads, humidifiers, tap water, water distillation systems, decorative fountains, dust.

Listeriosis

Pathogen: Listeria monocytogenes. Signs: Drooping eyelids, seeing double, blurry vision, dry mouth, slurred speech, trouble talking, trouble breathing, muscle weakness or paralysis, severe constipation. Reservoirs: Soil, water, mud, silage, infected mammals, humans, soft cheeses.

Tuberculosis (TB)

Pathogen: Mycobacterium tuberculosis. signs: Malaise, fever, night sweats, weight loss, productive cough, shortness of breath, chest pain, hemoptysis, hoarseness. Reservoirs: Infected humans, primates, cattle. transmission: Airborne droplets by infected person during coughing, sneezing, talking or singing; Prolonged direct contact with infected individuals.

Mycoplasmal Pneumonia (Primary atypical pneumonia - PAP)

Pathogen: Mycoplasma pneumoniae. signs: Gradual onset with headache, malaise, dry cough, sore throat, scant sputum then may increase. Reservoirs: Infected humans. transmission: Droplet inhalation, direct contact with an infect person, articles contaminated with nasal secretions or sputum of an ill, coughing patient.

Gonorrhea

Pathogen: Neisseria gonorrhoeae. Signs: Myalgia/arthralgia/polyarthritis/ dermatitis (disseminated); Urethral discharge/painful urination (men); Asymptomatic for weeks to months (women). Reservoirs: Infected humans. transmission: Direct mucous membrane to mucous membrane contact, sexual contact, adult to child (sexual abuse), mother to neonate during birth.

Rocky Mountain Spotted Fever

Pathogen: Rickettsia rickettsia. Signs: Sudden onset of moderate to high fever, extreme exhaustion, muscle pain, severe headache, chills, conjunctival infection, maculopapular rash (extremities) spreads to palms, soles and most of the body; Petechiae after 4 days.

Typhoid fever (enteric fever)

Pathogen: Salmonella typhi. Signs: Fever, severe headache, malaise, anorexia, rash on trunk, nonproductive cough, constipation. Reservoirs: Infected humans. transmission: Fecal-oral route, food or water contaminated by feces of urine of patients or carriers, oysters harvested from fecally contaminated waters, fecally contaminated fruits and raw vegetables, mechanical transmission by flies from feces to food.

Otitis media

Pathogen: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis. signs: persistent severe earache, temporary hearing loss, middle ear pressure, bulging ear drum.

Streptococcal Pharyngitis (Strep throat)

Pathogen: Streptococcus pyogenes (Group A strep, GAS, Strep A). signs: •Beefy red throat, White patches of pus (pharynx), Enlarged tonsils, Enlarged/tender cervical lymph nodes. Reservoirs: Infected humans. transmission: •Human to human (direct contact - hands), aerosol droplets, secretions from patients and nasal carriers, contaminated dust/lint/handkerchiefs, contaminated milk and milk products.

Syphilis

Pathogen: Treponema pallidum. Signs: Chancre (primary); Skin rash palms and soles (secondary); Long latent period; Damage to CNS, cardiovascular system, visceral organs, bones, sense organs (tertiary). Reservoirs: Infected humans.

Plague

Pathogen: Yersinia pestis. Signs: Fever, chills, malaise, myalgia, nausea, prostration, sore throat, headache. Reservoirs: Ground squirrels, fleas. transmission: Flea bite from rodent to flea to human, handling tissues of infected rodents, rabbits and other animals, droplet transmission.

Campylobacter enteritis

Pathogens: Campylobacter jejuni, Campylobacter coli. Signs: Asymptomatic, diarrhea, nausea, vomiting, fever, malaise, abdominal pain Reservoirs: Poultry, cattle, sheep, swine, rodents, birds, kittens, puppies, other pets.

EHEC Diarrhea

Pathogens: E. coli O157:H7, E. coli O26:H11, E. coli O111:H8, E. coli O104:H21. Signs: Hemorrhagic watery diarrhea, abdominal cramping. Reservoirs: Cattle, infected humans. transmission: Fecal-oral route, inadequately cooked fecally contaminated beef, unpasteurized milk, person to person contact, fecally contaminated water.

Salmonellosis

Pathogens: Salmonella enterica, Salmonella typhimurium, Salmonella enteritidis. Signs: Sudden onset of headache, abdominal pain, diarrhea, nausea, vomiting, dehydration. •Reservoirs: Poultry, swine, cattle, rodents, pet iguanas, turtles, pet chicks, dogs, cats.

Shigellosis (Bacillary Dysentery)

Pathogens: Shigella dysenteriae, Shigella flexneri, Shigella boydii, Shigella soneii. Signs: Diarrhea (20 bowel movements per day), with blood, mucus and pus; nausea, vomiting, cramps, fever, toxemia, convulsions. Reservoirs: Infected humans.

Cholera

Pathogens: Vibrio cholerae serogroup 01, Vibrio spp. Signs: Profuse watery stools, vomiting, rapid dehydration. Reservoirs: Infected humans, aquatic reservoirs. Mode of transmission: Fecal-oral route, contact with feces or vomitus of infected people, ingestion of fecally contaminated water or foods, mechanical transmission by flies.

Rocky Mountain Spotted Fever

Reservoirs: Infected ticks on dogs, rodents and other animals. transmission: Bite of an infected tick. Lab diagnosis: IDPs. Treatment: Antibiotics. Prevention: Avoid tick bites, Wear close toed shoes, Wear long pants and long sleeved shirts while hiking.

secondary sewage treatment

Second step in most waste treatment systems in which aerobic bacteria decompose as much as 90% of degradable, oxygen-demanding organic wastes in wastewater. It usually involves bringing sewage and bacteria together in trickling filters or in the activated sludge process.

contagious disease

a communicable disease that is easily transmitted from person to person. e.g. cold, respiratory flu, strep, ringworm, giardiasis.

infectious disease

a disease caused by a pathogen

pandemic

a disease that is occurring in epidemic proportions in many countries simultaneously. e.g. flu- spanish flu 1918, H1N1 2009-2010. HIV, TB, malaria.

Centers for Disease Control and Prevention (CDC)

a federal agency administered by the US department of health and human services. located in Atlanta, est. in 1946. certain infectious diseases must be reported, nationally notifibale diseases. publishes morbidity and mortality weekly report, MMWR.

epidemic disease

a greater than usual number of cases of a disease in a particular region, usually within a short period of time. e.g. legionnaires disease in 1976.

Incidence

a new number of cases of a particular disease in a defined population during a specific time period. e.g. during 2015, 500 ppl in NJ were newly infected with the flu.

Bacterial infections of the skin

acne. anthrax. gas gangrene. leprosy. staphylococcal. streptococcal.

How bacteria cause disease

adherence and colonization factors. factors that prevent activation of complement. factors that enable escape from phagocytosis. factors that prevent destruction within phagocytes.

nonliving reservoirs

air, soil, dust, contaminated water and foods, and fomites.

communicable disease

an infectious disease that can be transmitted from one host to another. e.g. hepatitis, polio, flu, HIV, malaria, TB.

incubatory carriers

capable of transmitting a pathogen during incubation period.

passive carriers

carry the pathogen without ever having had the disease.

water pollution

chemical pollution, biological pollution.

active carriers

completely recovered, but still harbor pathogen forever.

sewage treatment

consists mainly of water, fecal matter, garbage and bacteria. includes primary secondary, tertiary.

zoonotic diseases

diseases that humans acquire from animal sources. e.g. anthrax, avian flu, swine flu.

How bacteria cause disease

factors that suppress hosts immune system. endotoxins. production of exotoxins. production of necrotic and other types of destructive enzymes.

convalescent carriers

harbor and transmit a pathogen during the recovery phase of disease ex) chicken pox is contagious until all of the blisters have crusted over.

host factors dependent on occurrence of an infectious disease

health status, nutritional status, hygiene, age, travel, lifestyle.

living reservoirs

humans, pets, farm animals, insects, arachnids.

Fomites

inanimate objects capable of transmitting pathogens. e.g. bedding, towels, utensils, equipment, phones, keyboards.

WHO actions

investigates outbreaks of Ebola. eradicate smallpox. attempting to eradicate polio and dracunculiasis.

Diphtheria

lab diagnosis: Loeffler serum medium and cystine-tellurite or Tinsdale medium for culturing and identification. treatment: Abx, antitoxins. prevention: vaccine (DTap)

Leprosy

lab diagnosis: acid fast bacilli in skin smears or skin biopsy specimens. treatment: Abx. prevention: early diagnosis and treatment to prevent transmission, prophylaxis (60% effective).

Staphylococcal skin infections

lab diagnosis: biochemical or enzyme based tests, susceptibility testing must be performed due to multidrug resistance. treatment: Abx ointment, oral Abx, surgery (drain). prevention: hygiene, wound care.

acne

lab diagnosis: clinical grounds. treatment: creams, OTC cleansers, Rx Abx, cleansing routine. prevention: none.

gas gangrene

lab diagnosis: gram pos. or gram variable bacilli in smears of wound specimens. identified using biochemical or enzyme based tests. treatment: amputate, high dose Abx immediately. prevention: proper hygiene, lifestyle choices.

anthrax

lab diagnosis: isolation of pathogen from blood, lesions or discharges, identification using biochemical or enzyme based tests. treatment: Abx, antitoxins. prevention: vaccines, routine occupational exposure, prophylaxis.

primary sewage treatment

large solids are filtered out by screens and suspended solids settle out as sludge in a sedimentation tank.

Water Treatment

major steps: sedimentation, coagulation, filtration, chlorination. water is tested for fecal contamination by checking for the presence of coliform bacteria (E.coli).

Arthropods

many different types serve as reservoirs of infection like fleas, mosquitoes, lice. arachnids like mites and ticks.

zoonoses

may be acquired by direct contact with an animal, inhalation or ingestion of the pathogen, or injection of the pathogen by an arthropod. e.g. rabies, lyme, bird flu, anthrax.

Biological warfare (bw)

microbes purposely used to harm others in wartime.

sporadic disease

occurs only occasionally within a population of a particular geographic area. e.g. tetanus.

endemic disease

one that is always present within the population of a particular geographic area. e.g. gonorrhea.

human carriers

passive carriers, incubatory carriers, convalescent carriers, active carriers.

infectious disease process

pathogen. source of pathogen (resevoir). portal of exit. mode of transmission. portal of entry. susceptible host.

Anthrax

pathogen: Bacillus anthracis signs: eschars (cutaneous). reservoirs: infected animals, spores in soil, animal hair, wool, animal skins and hides, animal products. transmission: entry of endospores through breaks in skin, inhale spores, ingestion of bacteria in contaminated meat.

gas gangrene

pathogen: Clostridium perfringens. signs: tissue and muscle destruction, renal failure, shock. reservoirs: soil transmission: spores enter an open wound.

Diptheria

pathogen: Corynebacterium diprheriae. signs:

Bacterial conjunctivitis (pink eye)

pathogen: Haemophilus influenzae, aegyptius, Streptococcus pneumoniae. signs: irritation/reddening of conjuctiva, eyelid edema, mucopurulent discharge, light sensitivity. reservoir: infected humans.

Leprosy

pathogen: Mycobacterium leprae. signs: skin nodules (lepromatous), peripheral nerve damage with loss of sensation. reservoirs: infected humans. transmission: armadillos?, not clear.

Staphylococcal skin infections

pathogen: S. aureus. signs: infected hair follicle, boils, carbuncle, styes. reservoirs: infected humans. transmission: direct contact with purulent lesion or asymptomatic carrier, hands of healthcare workers.

Streptococcal skin infections

pathogen: Streptococcus pyogenes. signs: vesicular/pustular/encrusted stages (impetigo), pink/red rash (scarlet fever), fever/hot/red/tender eruptions (erysipelas), fascia inflammation (fascitis). reservoirs: infected humans.

bioterrorism agents

pathogens used to create fear, chaos, illness, and death in situations other than war. e.g. bacillus anthracis, smallpox virus, yersinia pestis (plague).

acne

pathogens: propionibacterium. signs/symptoms: comedomes. reservoirs: infected humans. mode of transmission: probably not transmissible.

Environment factors dependent on occurrence of an infectious disease

physical factors such as climate, season, location. availability of appropriate reservoirs. sanitary and housing conditions. availability of potted water.

otitis media

reservoirs: none. transmission: probably not communicable. lab diagnosis: C and S testing, B lactamase testing. treatment: Abx, self limiting. prevention: hygiene, vaccines (pneumococcal, flu).

World Health Organization (WHO)

specialized agency of the united nations founded in 1948. mission: to promote technical cooperation for health among nations. to carry out programs to control and eradicate diseases. to improve the quality of human life.

tertiary sewage treatment

specialized chemical and physical processes that reduce the amount of specific pollutants left in wastewater after primary and secondary treatments; usually inexpensive.

epidemiologists

study the factors that determine the frequency, distribution, and determinants of diseases in human populations. develop ways to prevent, control or eradicate diseases in pops.

point prevalence

the number of cases of a disease existing in a given population at a particular moment in time. e.g. right now.

period prevalence

the number of cases of a disease existing in a given population during a specific time period. e.g. during the year 2009

morbidity rate

the number of new cases of a particular disease that occured during a specified time period per a specifically defined population. (usually 1000, 10,000 or 100,000). e.g. during 2015, 50 ppl per 100,000 in NJ were newly infected with the flu.

mortality rate

the ratio of the number of ppl who died of a particular disease during a specified time period per a specified population. e.g. during 2015, 10 ppl per 100,000 died of flu in NJ.

Epidemiology

the study of diseases

CDC mission

to collaborate to create the expertise, information, and tools that people and communities need to protect their health.

Legionellosis (Legionnaire's disease, Pontiac fever)

transmission: Aerosols produced by vegetable misting devices in supermarkets. Lab diagnosis: Buffered charcoal yeast extract agar (culture), IDPs. treatment: Abx, self limiting. prevention: Wash fruits/vegetables; No hot tubs; Maintain water systems; Maintain air filtration system.

Syphilis

transmission: Direct contact with lesions, body secretions, mucous membranes, blood, semen, saliva, vaginal discharges of infected people; Sexual contact; Blood transfusions; Transplacentally from mother to fetus. Lab diagnosis: Darkfield microscopy, IDPs. Treatment: Abx. Prevention: Abstinence, Safe sex, Monogamy.

Shigellosis (Bacillary Dysentery)

transmission: Direct or indirect fecal-oral transmission from patients or carriers, fecally contaminated hands and fingernails, fecally contaminated food, milk and drinking water, mechanical transfer by flies from latrines to food. Lab diagnosis: Gram-negative enrichment broth and then onto MacConkey, XLD or HE agar, biochemical testing, IDPs. Treatment: Fluids, Abx, Rest. Prevention: Personal hygiene, Cleaning, Don't swallow water from ponds, rivers and lakes.

Genital Chlamydiasis

transmission: Direct sexual contact, mother to neonate during birth. Lab diagnosis: Cell culture, staining, IDPs. Treatment: Antibiotics. Prevention: Abstinence, Condoms, Long term monogamy.

Tetanus (lockjaw)

transmission: Does not occur. Lab diagnosis: Clinical and epidemiologic grounds. Treatment: Mechanical ventilation, Abx, Sedatives, Tracheostomy (some cases) and removal of unhealthy tissue. Prevention: Vaccine (Tdap or Td for adults).

Whooping Cough (Pertussis)

transmission: Droplets produced by coughing. Lab diagnosis: Bordet-Gengou agar or Regan-Lowe agar for culturing; Molecular diagnostic procedures; IDPs. Treatment: Abx. Prevention: Vaccine (DTaP), Handwashing.

Salmonellosis

transmission: Ingestion of contaminated food, fecal-oral transmission from person to person, food handlers or contaminated water supplies. Lab diagnosis: C and S testing, Non-lactose fermenters on MacConkey agar, biochemical testing, serotyping. Treatment: Self-limiting, Abx, IV fluids, Drinking fluids. •Prevention: Cook meats and eggs thoroughly, Clean areas with raw meat, Hand washing.

Campylobacter enteritis Term

transmission: Ingestion of contaminated food, raw milk or water; Contact with infected pets or farm animals or contaminated cutting boards. Lab diagnosis: Campy blood agar (culturing) Treatment: Self-limiting (2 to 5 days). Prevention: Proper food handling, Washing hands.

Bacterial Gastritis and Gastric Ulcers

transmission: Ingestion. Lab diagnosis: Culturing, urea breath test, NH4 excretion test, molecular diagnostic procedures, IDPs. Treatment: Antacids, Abx, Drinking water. •Prevention: Diet (avoid spicy, high fat foods, alcohol), Thoroughly cooking food.

Listeriosis

transmission: Mother to fetus in utero, Passage through an infected birth canal. Lab diagnosis: Gram stain, Culturing. Treatment: Antitoxin injections, Breathing assistance, IV fluids. Prevention: Use proper canning techniques, Avoid injectable street drugs, Seek medical attention for open wounds or cuts.

Clostridium difficile

transmission: Presence in hospital environment. Lab diagnosis: Commercial enzyme immunoassay, cytotoxin tissue culture assay. Treatment: Abx, Fecal transplant, Probiotics. Prevention: Handwashing, Hygiene, Avoid prophylaxis.

Tularemia (Rabbit Fever)

transmission: Tick bite, ingestion of contaminated meat or drinking water, entry of organisms into wound while skinning infected animals, inhalation of dust, animal bites. Lab diagnosis: Culture, biochemical tests, IDPs. Treatment: Abx. Prevention: Avoid handling dead animals; If you do handle dead animals - wear gloves.

Lyme disease

transmission: Tick bite. Lab diagnosis: Bull's eye rash (erythema migrans), IDPs, molecular diagnostic procedures, Barbour-Stoenner-Kelley medium (culturing). Treatment: Abx, NSAIDS. Prevention: Avoid tick bites, Wear close toed shoes, Wear long sleeved shirts and pants, Inspect body and pets, Apply repellent.

Ehrlichiosis

transmission: Tick bite. Lab diagnosis: IDPs, nucleic acid assays. Treatment: Antibiotics. Prevention: Avoid tick bites, Avoid open toed shoes, Apply repellent, Wear long pants and long sleeved shirts, Inspect your body and your pets.

Bacterial conjunctivitis (pink eye)

transmission: human to human via eye and respiratory discharge, tissues, clothing, contacts. lab diagnosis: microscopic examination of exudate, culture of pathogen, IDPs. treatment: eyedrops, Abx, cold compress, steroids. prevention: hand washing, dont touch eyes, hygiene, avoid infected people.

Streptococcal skin infections

transmission: person to person (respiratory drops). lab diagnosis: biochemical or enzyme based tests, rapid strep test. treatment: Abx (some resistant). prevention: hygiene, dont share personal items.

indirect contact

via airborne droplets of respiratory secretions (sneezing coughing). food water contaminated by fecal matter. arthropod vectors. fomites. transfusion of contaminated blood or blood products or parenteral injection.

pathogen factors dependent on occurrence of an infectious disease

virulence, mode of entry, number of organisms -E. coli (10 6 to 10 8) -salmonella (>10 5) -bacillus anthracis (10 4 spores) -cryptosporidium parvum (10-30 oocyts) -escheria coli O157:H7 (<10) -mycobacterium tuberculosis (<10) -entamoeba coli (1 cyst)

vectors

when arthropods are involved in the transmission of infectious diseases.

Diphtheria

•Pathogen: Corynebacterium diphtheriae. Signs: Gray-white membrane (throat), sore throat, swollen/tender cervical lymph nodes, tonsillitis, neck swelling. Reservoirs: Infected humans. transmission: •Airborne droplets, direct contact, contaminated fomites.