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133 Cards in this Set

  • Front
  • Back
what is an infection and when does it occur?
disease or condition caused by a microorganism

occurs when part of a microorganism's life cycle involves you
what is the process by which an infectious agent passes from one organism to another
chain of infection
what is an infectious agent capable of causing disease?
pathogen
what are the stages of infection?
1. incubation period (no symptoms)

2. prodromal period

3. invasive phase

4. acme (peak)

5. decline phase

6. convalescent period

7. sequelae (remaining symptoms the body can't repair)
what is the widespread outbreak of a disease that affects many people?
epidemic
it is estimated that there are more types of ____ than all other creatures combined
viruses
what type of pathogen cannot reproduce on its own and replicate only inside another organism?
virus
what is a single-celled organism classified by shape, cell wall, and growth requirements?
bacteria
what is bacteria that live on/in a host at a particular location without causing harm and sometimes benefitting the host?
normal flora
what is the least understood infectious agent that is responsible for mad cow disease?
prions
which pathogen is said to be made entirely of protein, found in brain tissue, and alters other proteins?
prions
what causes a yeast infection?
candida, which is a fungus
what are organisms that live on/in a host and get food at the expense of the host?
parasites: include helminths, protozoa, and ectoparasites
what infectious agent are parasitic worms including roundworms, flukes, and tapeworms?
helminths
what infectious agent attaches to the human intestine and causes blood loss, and is the leading cause of anemia and malnutrition in developing countries?
hookworm
what infectious agent is the leading cause of disease and death in africa, asia, and central and south america which includes pneumonia and malaria?
protozoa
what infectious agent live on or in the skin and include fleas, ticks, lice, mosquitoes, and scabies?
ectoparasites
bacteria can double every ___ minutes
20
what is the first line of defense against infection?
skin
what are tiny, hairlike structures that rhythmically push foreign particles up and out, and where are they located?
cilia, in the lungs
what is an enzyme that breaks down bacteria and reduces the likelihood of infection?
lysozyme
what infectious agent causes chlamydia, gonnorrhea, meningitis, and tuberculosis?
bacteria
what is the complex set of cells, chemicals, and processes that protects the body against pathogens when they succeed in entering the body?
immune system
what 3 functions does the immune system perform?
1. recognize foreign particles or infectious organisms

2. attack & destroy these agents

3. communicate with other parts of the immune system about when to begin and end an attack
what is the part of the immune system designed to rapidly dispose of pathogens in a non-specific manner?
innate immune system
what is an animal or insect that transmits a pathogen from a reservoir or an infected host to a new host?
vector
what is the speed and intensity with which a pathogen is likely to cause an infection?
virulence
what is the part of the immune system that recognizes specific targets?
acquired immune system
what is the series of cellular changes that bring blood to the site of an injury or infection?
acute inflammatory response. part of the innate immune system
what are the cells of the innate immune system?
neutrophils, macrophages, and natural killer cells. neutrophils and macrophages are white blood cells that travel to the infection. natural killer cells are white blood cells that recognize and destroy virus infected cells or cells that have become cancerous
what are "cell eaters" that digest damaged cells, foreign particles, and bacteria?
phagocytes
what are white blood cells that circulate in the bloodstream and lymphatic system, and what are they a part of?
lymphocytes. part of the acquired immune system
what is the network of vessels and organs throughout the body that serves to move fluid from body tissues and clear infection, and what organs does it include?
lymphatic system. it includes the lymph nodes, spleen, and thymus
what is the marker on the surface of a foreign substance that identifies it to immune cells as "nonself"?
antigen
what are the two main types of lymphocytes and what do they do?
T cells: monitor events that may be occurring inside the body's cells. indicates infected cells as "nonself"

B cells: monitor the blood and tissue fluids. produce antibodies
explain helper T cells, killer T cells, and suppressor T cells
helper T cells read the message of T cells and trigger the production of killer T cells and B cells. they also enhance the activity of the cells of the innate immune system and of B cells once they are activated

killer T cells attack and kill foreign cells and body cells that have been infected by a virus or have become cancerous

suppressor T cells slow down and halt the immune response when the threat has been handled
what are proteins that bind to specific antigens and trigger events that destroy them? What are the events?
antigens. they may neutralize the pathogen themselves because they are bound to the antigen, or signal other cells to destroy it, or activate parts of the innate immune system to destroy the pathogen
what is reduced susceptibility to a disease based on the ability of the immune system to remember, recognize, and mount a rapid defense against a pathogen it has prevously encountered?
immunity
when was the concept of immunization first introduced and by whom? what disease made him figure it out?
1796 by edward jenner

he realized that people infected with cowpox seldom became ill of smallpox
what are preparations of weakened or killed microorganisms or parts of the microorganisms that are administered to confer immunity to various diseases?
vaccines. developed by jenner
what are the benefits of breast feeding?
benefits: reduced infections, allergies, and diarrhea. promote good health later in life. transferring antibodies from some diseases
what is temporary immunity provided by antibodies from an external source - such as passed from mother to child in breast milk?
passive immunity
what are some uncontrollable risk factors of infectious diseases?
age (young & old are most at risk), surgery, chronic diseases such as diabetes, being bedbound, genetic disposition, sociocultural factors, overcrowded living environments, and poverty (poor nutrition, stress, lack of health care)
what are two types of malfunctions of immunity?
autoimmune disease and allergies
what are the causes of autoimmune diseases?
- a part of the body is similar enough to an antigen on a foreign agent that the immune system mistakenly identifies it as "nonself"

- the immune control system fails to turn off an immune response once an infection is over

these cause self-destruction, causing damage to body cells and tissues
what are some autoimmune diseases and who is more likely to have them?
psoriasis, rheumatoid arthritis, multiple sclerosis, scleroderma, lupus erythematosis

more common in women than men
how do allergic reactions occur?
when the immune process identifies a harmless foreign substance as an infectious agent and mounts a full-blown immune response
what is the condition that is caused by inflammation of the bronchial tubes and spasm of the muscles around the airways in response to an allergen or other trigger?
asthma

it is characterized by wheezing and shortness of breath
what is the hypersensitive reaction in which an antigen causes an immediate and severe reaction that can include itching, rash, swelling, shock, and respiratory distress? what drugs are used to treat it?
anaphylactic shock

antihistamines for mild allergies, steroids to decrease an immune response, and epinephrine in emergency situations to reduce swelling
stress and the immune system
long-term stress reduces the immune system, but short-term stress can actually enhance its functioning by activating the body's responses to stressors like puncture wounds, scrapes, and animal bites
is it clear that stress causes illness?
NO. more than 300 studies in the last 30 years have verified it, but it is still not 100% sure
how often should you get a tetanus shot?
every ten years should get a booster called diphtheria (Td) vaccine
who are most susceptible to influenza?
children age 6 months to 5 years, pregnant women, people aged 50 or older, and people with chronic health conditions
how many americans have asthma? who are most at risk? is it genetic?
20 million americans have it, 9 million are children. people with allergies are more at risk along with children. it does run in families
infections from blood banks have (increased, decreased) in recent years
decreased
how many organisms are associated with food-related illnesses?
250
SARS
severe acute respiratory syndrome

it is caused by a previously unknown carona virus and is spread by coughing, sneezing, skin contact, and through air.

it has no vaccine or treatment, and incubation period is 2-10 days.

air travel was a key reason for why it spread

symptoms can progress rapidly to a severe form of pneumonia
what are some variables associated with the susceptibility to infection if exposed to an STD?
- gender

- age at first intercourse

- general health of the susceptible person

- women are at greater risk because they have a larger mucosal surface of the vagina and cervix

- young women because cervix is more susceptible to infection in the first few years of menstruation

- abrasions
condoms and STDs
not 100% effective at preventing STDs

there is no data if they reduce the risk of transferring HPV
what are the ABCDs of STD prevention?
- abstinence

- be faithful

- condoms

- detection is critical. some STDs have no symptoms
all hepatitis viruses cause ______
inflammation of the liver

symptoms include fatigue, weakness, loss of appetite, and jaundice
what percent of blood transfusion recipients before 1990 developed hepatitis?
10%, mostly hepatitis C
how many americans are infected with hepatitis C?
4.1 million
what is the incubation period of hepatitis C?
4-6 weeks
what percent of people infected with hepatitis C show symptoms?
20%
what percentage of people with hepatitis C will develop liver failure after 20 years?
1/5
what is scarring of the liver called?
cirrhosis
what is the leading reason for the need of liver transplants?
hepatitis C
what have community programs done to reduce the risk of hepatitis C?
they have been linking drug users with treatment programs and encouraging safe injection programs for addicts until they can receive treatment
how do people who have hepatitis C slow the progression?
avoiding alcohol, limiting use of medications that affect the liver (such as acetaminophen), and getting vaccinated for hepatitis A and B
what bacterial infection has been recently associated with tattooing?
methicillin-resistant staphylococcus aureus (MRSA)
what is a drug that works by killing or preventing the growth of bacteria?
antibiotic
when was penicillin discovered and by whom?
1928 by alexander fleming

it is a common mold, and was the first antibiotic
what is the lessened sensitivity to the effects of an antibiotic?
antibiotic resistance
what 2 factors contribute to antibiotic resistance?
1. the frequency with which resistant genes arise naturally among bacteria through mutation

2. the extent of antibiotic use
antibiotics are _____, so they kill ______ as well as pathogens and increase antibiotic resistance in _____ as well as in pathogens
nonspecific; helpful bacteria; helpful bacteria
antibiotics are estimated to be not needed in up to _____ percent of the cases in which they are prescribed
50%
what percent of antibiotics produced are used on livestock?
70%
what program, run by the CDC and FDA, collects and analyzes information on possible adverse events that occur after vaccinations?
the vaccine adverse events reporting system
what is the leading cause of infectious disease and death?
pneumonia
what disease is described as an infection of the lungs or lower respiratory tract?
pneumonia
who are most at risk for pneumonia?
young children and older adults

risk factors also include environmental pollutants, tobacco use, alcohol use, drug use, and close living situations
is pneumonia viral or bacterial?
can be both

viral is milder, but both can be deadly
what is the problem with treatment for pneumonia?
up to 40% of the streptococcus bacterium that causes it is resistant to penicillin, and 96% of influenza A (causes pneumonia) is resistant to 2/4 of the antiviral drugs
who is most at risk for diarrhea?
children. it kills 2-3 million children each year
what can diarrhea lead to and what causes it? how can it be prevented?
can lead to dehydration, electrolyte imbalances, malnutrition, and growth delay

caused by viruses and bacteria

25% of diarrhea deaths are caused by the rotavirus

spread through contaminated food and water, so sanitation and clean water reduce the risk
what is the most common infectious disease worldwide? what percent of the population is infected?
tuberculosis; 30%
what kind of infection is not currently active but could reactivate at a later time?
latent infection
describe tuberculosis
it is caused by a mycobacterium, a subset of bacteria

it is a latent infection, and only 5-10% of infected people develop the active disease

symptoms of active tuberculosis include cough, fatigue, weight loss, night sweats, fever, and coughing up blood
tuberculosis is the leading cause of death among what kind of people?
people infected with HIV
is there a treatment for tuberculosis?
yes. a combination of 3-4 anti-TB drugs taken for 6-9 months. some types of TB are resistant which has caused a large public health concern
describe malaria, including who's at risk, where it is common, symptoms, and treatment
it is a mosquito-borne disease caused by four species of the plasmodium parasite

deaths occur mostly among young children

most deaths occur in sub-saharan africa

symptoms include high fever, chills, sweats, headache, nausea, comiting, and body aches. symptoms develop 7-30 days after being bit

severe malaria can lead to confusion, seizures, coma, heart failure, kidney failure, and death

treatment varies depending on the type

the anopheles mosquito is still present in many southern states and periodically causes small outbreaks of malaria
what is the name for the infection of the respiratory tract caused by the pertussis bacterium?
whooping cough
among students with a prolonged cough, about ____ percent have whooping cough
30%
how is influenza catagorized?
influenza A and B cause the flu

influenza A is broken up into subtypes based on antigens on the surface of the virus, called H and N

there are only three influenza A subtypes that affect humans (H1N1, H1N2, and H3N2)
avian flu
H5N1

in asian countries among domesticated birds with some humans infected by the birds, not by other humans

humans do not have immunity to it

in some areas, 50% of people with avian flu have died

vaccination would not be effective because it changes

could lead to a pandemic
what is a viral disease characterized by fever, headache, and swollen salivary and parotid glands?
mumps
transmission and treatment of mumps
transfered by respiratory secretions from an infected person

no treatment
what is a common bacterium carried on the skin or in the noses of healthy people and is one of the most common causes of skin infection?
staphylococcus aureus (staph)
what is the most common bacterial infection?
urinary tract infection (UTI)
UTI statistics
more common in women

1/3 of women will have a UTI by age 24

more than 50% of women will have at least one UTI in their lifetime

usually involve the lower urinary tract or bladder

mostly caused by the bacteria E. coli
the primary pathogens responsible for STDs are ______ and _______
viruses and bacteria
HIV/AIDS statistics
2.5 million new infections and 2.1 million deaths occured with 3/4 being sub-saharan africans

in sub-saharan africa, it is mostly heterosexual contact, with 61% infected being women

1.3 million are infected with HIV in north america

sexual contact is involved in 85% of newly diagnosed HIV infections in the US, with over half being homosexual contact and 18% being intraveneous drug use
how did HIV start?
from the simian immunodeficiency virus found in chimpanzees in africa
what is the name for the level of the HIV virus that continues to circulate in the blood and body fluids and causes the person to be asymptomatic for 2-20 years?
viral load set point
what are infections that occur when the immune system is weakened and do not usually occur in a person with a healthy immune system? what are common diseases that have this?
opportunistic infections

AIDS, pneumonocystis carinii pneumonia, kaposi's sarcoma, and tuberculosis
the time of highest circulating virus is at what time?
shortly after initial infection
what percent of people in the US do not know they are infected with HIV?
25%
what is the transmission of a disease from an infected mother to her child called?
perinatal transmission
what medications can be used to prevent a mother from transferring a disease to her baby?
antiretroviral
what percent of treated and untreated women infect their baby?
untreated = 30%

treated = 2%
what percent of US citizens know their HIV status? what about sub-saharan africa?
75% in US

12% of men and 10% of women in sub-saharan africa
what are complicated drug combinations used to overcome drug resistance in different strains of HIV?
drug cocktails
what is the name for a compound or chemical in the form of a cream, gel, or suppository that would kill microorganisms and that could be applied topically to the vagina or rectum before intercouse, reducing the risk of STD transmission?
microbicide
what percent of people age 18-26 have chlamydia?
4.1%
who has the highest rates of chlamydia?
young women, particularly african american women
what percent of men and women show no signs of chlamydia?
women: 75%

men: 50%
name some bacterial STDs
chlamydia, gonorrhea, pelvic inflammatory disease, syphilis, and bacterial vaginosis
who has the highest rates of gonorrhea?
young women
what antibiotics treat gonorrhea?
used to be fluoroquinolones, but now is cephalosporins
what disease occurs when bacteria from the vagina or cervix spread upward into the uterus and fallopian tubes?
pelvic inflammatory disease (PID)
what disease is caused by infection from the bacterium treponema pallidum and is increasing in men having sex with men?
syphilis
what disease is caused by the normal vaginal flora (lactobacillis) being replaced with different bacteria, causing vaginal discharge and unpleasant odor?
bacterial vaginosis
what percent of the general population and what percent of men and women on college campuses have HPV?
15% of general population

46% of women on college campuses

over 50% in men who have sex with men
what are some viral STDs?
HPV, herpes, hepatitis
can you spread herpes when there isn't a visible lesion?
yes
can herpes be transmitted to a newborn during delivery? when is the greatest risk of infection?
yes

greatest risk is when a woman is infected toward the end of her pregnancy. women with it should get a c-section
how is hepatitis A transmitted?
through fecal-oral contact and through contaminated food or water
how is hepatitis B transmitted?
mostly sexually transmitted but can also be spread through infected blood
which hepatitis causes chronic liver disease?
hepatitis B
what is commonly mistaken for as an STD and is caused by a protozoa? how is it treated?
trichomoniasis ("trich")

treated with the antibiotic metronidazole
what percent of women have had an episode with candidiasis in their lifetime?
75%
which country has the highest rates of STDs?
the US

we are 50-100 times higher than those of other industrialized countries