Microbio Exam 1 Diseases

Plague Infectious Agents

Plague Infectious Agents

yersinia pestis: gram negative rod shaped bacteria

Plague Transmission

flea is a vector: bacterium replicates in the flea gut and cells of Yersinia pestis are transmitted by regurgitation once the flea bites its next host

rats: reservoir

flea bites, contact with contaminated fluid or tissue, and infectious droplets

Zoonosis

a disease primarily in animals that can be transmitted to humans

ex: plague

Enzootic

an endemic disease present in an animal population

Endemic

a disease already present in a population, but only one location is affected

Epizootic

an epidemic disease present in a population

Bubonic Plague

most common form

results from bite from infected flea

bacteria multiply in lymph node near bite

patients develop one or more swollen painful lymph nodes (buboes), fever, and a headache

if patient is not treated with antibiotics, bacteria can spread to other parts of the body via bloodstream

Pneumonic Plague

only type that spreads person to person (by infectious droplets)

is untreated bubonic plague or septicemic plague that spreads to the lungs

Septicemic Plague

rapid spread via the bloodstream

severe, causes bleeding into skin and organs and septic shock

Diagnosing the Plague

taking a sample from blood or part of a swollen lymph gland and sending it to be tested

visualizing small gram shaped bacteria with gram stain

bipolar staining with wright, giemsa, or wayson stains (bacteria safety pin shaped)

a known flea bite or buboes

ELISA test

Treatment for Plague

intravenous or oral antimicrobials depending on the severity of illness

quarantine for those in close contact with patients

preventive antibiotic therapy

no vaccine

Plague Prevention

hand washing, control of rodents and fleas, wearing gloves if handling wild animals, and bug repellant

Vector

an animal capable of passing a disease on

ex: fleas for plague

Reservoir

species where the disease is present and thriving, doesn’t spread disease

ex: rats for plague

Smallpox Vaccine Creation

created by Edward Jenner and was the 1st successful vaccine developed

observed milkmaids immune to cowpox become immune to smallpox, he then began injecting healthy people with diseased cells to make them immune = variolation

Smallpox Causes

caused by orthopox, a variola virus, DNA virus that replicated in the cytoplasm: has 2 major forms

1. variola major: higher mortality rate

2. variola minor: lower mortality rate

Smallpox Transmission

humans are the only reservoir

direct face to face contact

coughing and sneezing

contaminated objects - not wearing gloves

patients first become contagious after first sores appear

remain contagious till last sore falls off

Smallpox Symptoms

1. initial symptoms: high fever, head and body aches, sometimes vomiting, can sometimes be contagious

2. early rash: most contagious, lasts 4 days

3. pustular rash and scabs: contagious and lasts 10 days

4. scabs fall off: contagious, lasts about 6 days

5. no scabs: 4 weeks after rash appears, scabs should have fallen off and patient is no longer contagious

Measles (Rubeola)

negative sense, single stranded, enveloped RNA virus

caused my morbillivirus in paramyxovirdae family

very contagious and humans are the only natural host

Measles Symptoms

starts with flu/cold like symptoms

high fever

kopliks spots: white spots on buccal mucosa, inner cheeks

rash on face moving downwards from hairline to extremities

triple c: cough, coryza (runny nose), and conjunctivitis

Measles Spreading

highly contagious that lives in the nose and throat mucus

can spread through coughing and sneezing and touching infected objects

animals don’t get or spread it

Measles Symptoms

7-14 days after infection: first symptoms show, high fever, cough, runny nose (coryza), and red watery eyes

2-3 days after symptoms: kopliks spots, tiny white spots inside the mouth

3-5 days after symptoms: rash, begins as flat red spots on hairline that move down to the legs, can also be small raised bumps, begin to join together as more appear down the body, high fever

Those at Risk of Measles

children younger than 5

adults older than 20

pregnant women

people with compromised immune systems like those with HIV or leukemia

Measles complications

common: ear infections and diarrhea

rare: subacute sclerosing panencephalitis - SSPE, severe neurological symptoms

Measles Diagnosis

determining signs and symptoms like koplik spots

detection of measles specific antibodies in serums and RNA by real time polymerase chain reactions

urine samples

Measles Treatment

no antiviral therapy available

medical care is supportive and can only help relieve symptoms and address complications

vitamin A can be administered after diagnosis

can be prevented with a vaccine

isolate those who have developed a measles rash- airborne spreading