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Activity: Which Disease Is the Worst?

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    Each of the following is a disease found in humans. Read each of the descriptions and decide as a group how you would organize the diseases into 2­5 major groups, and then 2­5 subgroups. Be able to defend your choices to the class.

    African Sleeping Sickness

    Infectious Agent: Protist, Trypanosoma
    Symptoms: headaches, abnormal behavior, uncontrollable sleepiness
    Transmission/Vector: tse tse fly
    Prevention: control insect population
    Additional Notes: some game animals carry trypanosomes which are passed to tse tse flies


    Amebic Dysentery

    Infectious Agent: Protist, Ameba histolytica
    Symptoms: violent diarrhea, foul smelling flatulence, dehydration
    Transmission/Vector: contaminated water and food
    Prevention: purify / filter water
    Additional Notes: common in developing countries, sometimes called "traveller's diarrhea"


    A.I.D.S (Acquired Immune Deficiency Syndrome)

    Infectious Agent: Human Immunodeficiency Virus (H.I.V)
    Symptoms: pneumonia, certain types of cancer, opportunistic infections
    Transmission/Vector: intimate contact, exchange of blood or body fluids
    Prevention/Treatment: blood screening, safer sex; anti­viral drugs
    Additional Notes: Drugs can be used to slow disease progression, there is no cure or vaccine

    File:HI-Virion sans libel.png


    Infectious Agent: Bacteria, Bacillus anthracis
    Symptoms: respiratory failure, flu­like symptoms,
    Transmission/Vector: infected meat
    Prevention: Vaccines can be given to at­risk populations (military), avoid contact with infected persons or animals
    Additional Notes: Anthrax spores can survive for long periods, making anthrax an possible pathogen for bioterrorism (anthrax can be mailed in envelopes). There are also gastrointestinal and cutaneous forms of infection.

    File:Anthrax spores (5940425745).jpg

    Black Death

    Infectious Agent: Bacteria, Yersinia pestis
    Symptoms: Appearance of buboes (masses) in the groin and armpits, vomitting, rashes, black spots
    Transmission/Vector: Fleas on rats
    Prevention/Treatment: Avoid areas where infection is present; antibiotics
    Additional Notes: Disease is treatable with antibiotics. The Black Plague is thought to have killed 30­60% of Europe's population in the 14th century.

    File:Flea infected with yersinia pestis.jpg


    Infectious Agent: Bacteria, Vibrio cholera
    Symptoms: watery diarrhea, vomitting, dehydration, muscle cramps
    Transmission/Vector: contaminated water and food (oysters)
    Prevention/Treatment: water filtration, sanitation; antibiotics
    Additional Notes: Vaccine is available, but not widely given. Cholera can be fatal if untreated and was devasting before antibiotics and intravenous fluids. John Snow, the father of epidemiology was the first to track this diseaes and establish its cause.

    Cholera bacteria SEM.jpg

    Creutzfeltd­Jakob Disease (CJD)

    Infectious Agent: scrapie prion
    Symptoms: deteriorating mental capacity, confusion, dementia, death
    Transmission/Vector: unknown causes, contamination from infected tissue, cannibalism also implicated, possible transmitted from the bovine form (Mad Cow Disease)
    Prevention: not applicable, unknown
    Additional Notes: Also called spongiform encephalitis, for the spongy appearance of the brain in deceased victims


    Chagas Disease

    Infectious Agent: Protist; Trypanosoma cruzi
    Symptoms: initially flu­like symptoms, swelling of eyelids; heart disorders and digestive problems in chronic phase
    Transmission/Vector: Kissing Bug bite
    Prevention/Treatment: Control of insects, anti­parasitic drugs
    Additional Notes:

    File:Three species of kissing bugs.PNG


    Infectious Agent: Ebola Virus
    Symptoms: flu­like symptoms, vomiting, bleeding due to decreased blood clotting (hemorrhagic fever)
    Transmission/Vector: close contact with infected individuals or handling of corpses, animal resevoir (bats) suspected
    Prevention/Treatment: avoid contact with infected, there is no cure, treatment usually involves IV fluids
    Additional Notes: High risk of death to those affected (20­90%), usually within 16 days of when symptoms appear

    File:Ebola virus em.png

    Giardiasis (Beaver Fever)

    Infectious Agent: Protist, Giardia lamblia
    Symptoms: weakness, loss of appetite, loose stools, projectile vomiting, excessive gas, weight loss
    Transmission/Vector: Drinking water contaminated with the parasite, can infect animals
    Prevention: Sanitation, clean water
    Additional Notes: This is also called "hiker's diarrhea" because hikers will get this if they drink from what appears to be clean streams. Always filter the water!

    Giardia lamblia SEM 8698 lores.jpg


    Infectious Agent: parasitic roundworm, Anclystoma and Necator
    Symptoms: Intestinal inflammation, anemia, can by asymptomatic
    Transmission/Vector: larval worms burrow through the skin, adult worms live in the intestine, animals can carry roundworms
    Prevention: wear shoes, keep pets de­wormed, sanitation
    Additional Notes: The site of infection is often visible on the skin, where the larval worm has burrowed.

    File:Hookworm filariform A.jpg


    Infectious Agent: virus, Influenza (multiple strains)
    Symptoms: high fever, aches, headache, fatigue, sore throat, coughing
    Transmission/Vector: air, contact with infected
    Prevention: vaccines, handwashing, avoid infected
    Additional Notes: the 1918 flu pandemic was described as the "greatest medical holocaust in history" and kiled more people than the black death, and more people in 24 weeks than AIDS has killed in 24 years, approximately 50­100 million worldwide

    Leprosy (Hansen's Disease)

    Infectious Agent: bacteria, Mycobacterium leprae
    Symptoms: skin lesions, nerve damage
    Transmission/Vector: spread in respiratory droplets
    Prevention/Treatment:avoid contact with infected; antibiotics
    Additional Notes: Once a feared disease, victims were sometimes assigned to leper colonies, the disease takes its name from the Latin word "lepra" which means scaly ­ due to the scaly appearance of the skin of those infected



    Infectious Agent: protist, Plasmodium
    Symptoms: fever, chills, anemia, liver failure
    Transmission/Vector: Anopholes mosquito transmits the protist through bites
    Prevention/Treatment: Mosquito nets, insecticides; anti­malarial drugs can prevent infection
    Additional Notes: Generally a tropical disease, though it has huge effects across the world; in 2010 there were 219 million cases that resulted in 660,000 deaths. Scientists have been researching a vaccine for decades, but have made little progress



    Infectious Agent: Virus, poliomyelitis
    Symptoms: fever, headache, fatigue, muscle pain, paralysis
    Transmission/Vector: ingestion in contaminated food or water
    Prevention: Vaccines were developed in 1955 (Jonas Salk)
    Additional Notes: Some patients were confined to "iron lungs" that would help them breath because the virus interfered with those muscles. Many children were affected by the disease and lost the ability to walk, a condition called "infantile paralysis."

    File:Polio physical therapy.jpg


    Infectious Agent: Virus, Rabies
    Symptoms: confusion, paranoia, paralysis, disorientation, hydrophobia
    Transmission/Vector: Animal bites or scratches
    Prevention:Vaccinate dogs, avoid contact with bats or other wild animals
    Additional Notes: Rabies is always fatal, there is no cure. There is a vaccine that is given if a person has been exposed to a rabid animal.

    Schistosomiasis (Snail Fever)

    Infectious Agent: Roundworm, Schistosome worm
    Symptoms: fever, anemia, organ failure, enlarged liver, blood in urine, bloody stool
    Transmission/Vector: cercariae larva live in snails for part of life cycle, then burrow into skin of humans
    Prevention: Control snail populations with insecticides, sanitation and clean water
    Additional Notes:


    Strep Throat

    Infectious Agent: Bacteria, Streptococcus pyogenes
    Symptoms: painful throat, swollen tonsils, may be coated with white patches
    Transmission/Vector: Casual contact with infected, respiratory droplets
    Prevention/Treatment: wash hands, disinfect, antibiotics, tonsillectomy may be recommended
    Additional Notes:


    Infectious Agent: Virus, Variola major and Variola minor
    Symptoms: intense rash with raised fluid­filled blisters, scarring occurs in survivors
    Transmission/Vector: Respiratory droplets, airborne
    Prevention: Avoid infected, vaccination
    Additional Notes: Vaccines for smallpox no longer given as it has been declared eradicated from the human population. The vaccine was created by Edward Jenner from cowpox and is the first known vaccine ever used.


    Infectious Agent: Bacterium, Treponema pallidum
    Symptoms: four stages, each with a different set of symptoms ranging from skin ulcerations, rashes, and finally growths that occur under the skin and can cause deformities (growths are called gummas), neurological and cardiac symptoms finally result in death
    Transmission/Vector: Sexual contact, or from mother to fetus
    Prevention/Treatment: Condoms can prevent infection, antibiotics are used to treat it
    Additional Notes: Syphilis can be latent, with person having no symptoms at all. It was a feared disease of Europe in the days before antibiotics. Many historical figures are thought to have had neurological symptoms of stage 4 syphilis (Napolean, Hitler)

    File:Syphilis Bacteria (16842837731).jpg


    Infectious Agent: Bacteria, Clostridium tetani
    Symptoms: muscle spasms, lockjaw, death
    Transmission/Vector: Enters the skin through cuts or punctures
    Prevention: Vaccine
    Additional Notes: There is no cure or treatment once symptoms occur, it is fatal


    Infectious Agent: Roundworm, trichinella
    Symptoms: muscle soreness
    Transmission/Vector: eating undercooked food (usually pork)
    Prevention: cook food thoroughly
    Additional Notes: Cysts remain in muscles and cannot be removed


    Whooping Cough (Pertussis)

    Infectious Agent: Bacteria, Bordatella pertussis
    Symptoms: startw with mild respiratory symptoms, followed by paroxysmal cough, fainting or vomiting due to violent coughing, gasping for breath
    Transmission/Vector: Airborne, person to person
    Prevention: Vaccine developed in the 1930's, completely prevents disease
    Additional Notes: Because some communities are having a high opt­out vaccination rate, pertussis is making a comeback. It can be fatal in young children. Adults are recommended to get boosters if they are around vulnerable children. Pertussis vaccines are packaged with tetanus vaccines.

    This page titled Activity: Which Disease Is the Worst? is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Shannan Muskopf (Biology Corner) .

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