Chapter 20.3 Diseases Caused by Bacteria and Viruses Flashcards
What are pathogens?
disease-causing agents
What are the most common types of pathogens?
bacteria and viruses
What are all the currently known prokaryotic pathogens?
bacteria
How do bacteria cause disease?
by destroying living cells and their tissue or by releasing chemicals that upset homeostasis
How does the bacterium that causes tuberculosis damage host tissue?
this pathogen is inhaled into the lungs where its growth triggers an immune response that can destroy large areas of tissue
can also travel through blood vessels to other sites in the body, causing similar damage
What is an example of bacteria that produces toxins?
the species that causes diphtheria
the species that causes botulism
What is botulism?
a deadly form of food poisoning
LYME DISEASE effect on the body (4)
bacterial disease
- “bull’s-eye” rash at site of a tick bite
- fever
- fatigue
- headache
LYME DISEASE transmission.
ticks transmit the bacterium Borrelia burgdorferi
TETANUS effect on the body (6)
bacterial disease
- lockjaw
- stiffness in neck and abdomen
- difficulty swallowing
- fever
- elevated blood pressure
- severe muscle spasms
TETANUS transmission
bacteria enter the body through a break in the skin
TUBERCULOSIS effect on the body (7)
bacterial disease
- fatigue
- weight loss
- fever
- night sweats
- chills
- appetite loss
- bloody sputum from lungs (coughing up blood)
TUBERCULOSIS transmission
bacteria particles are inhaled
BACTERIAL MENINGITIS effect on the body (5)
bacterial disease
- high fever
- headache
- stiff neck
- nausea
- fatigue
BACTERIAL MENINGITIS transmission (2)
- bacteria are spread in respiratory droplets caused by coughing and sneezing
- close or prolonged contact with someone infected with meningitis
STREP THROAT effect on the body (5)
bacterial disease
- fever
- sore throat
- headache
- fatigue
- nausea
STREP THROAT transmission
direct contact with mucus from an infected person or direct contact with infected wounds or breaks in the skin
What are the 5 ways to control bacteria?
- physical removal: wash hands
- disinfectants: chemical solutions that kill bacteria
- food storage: low temperatures slow the growth of bacteria
- food processing: cooking foods at a certain high temperature kills bacteria
- sterilization by heat: objects like medical or surgical tools can be heated above 100 degrees Celsius to kill bacteria
What is a vaccine?
a preparation of weakened or killed pathogens or inactivated toxins
What happens when a vaccine is injected into the body?
a vaccine prompts the body to produce immunity to specific disease
What is immunity?
the body’s ability to destroy pathogens or inactivated toxins
How can many bacterial diseases be prevented?
by stimulating the body’s immune system with vaccines
What are antibiotics? Examples?
compounds that block the growth and reproduction of bacteria
ie. penicillin and tetracyline
What do antibiotics do?
they disrupt bacterial proteins or bacterial cell processes, but do not harm the host cells!
Do antibiotics work on viruses?
NO!
How do viruses cause disease?
by directly destroying living cells or by affecting cellular processes in ways that upset homeostasis
can cause cells to change growth/development patterns, leading to cancer
actually penetrating cells (injecting DNA/RNA into cells)
What does poliovirus do?
destroys cells in the nervous system, producing paralysis
COMMON COLD effect on the body (5)
viral disease
- sneezing
- sore throat
- fever
- headache
- muscle aches
COMMON COLD transmission (2)
- contact with contaminated objects
- droplet inhalation
INFLUENZA effect on the body (7)
viral disease
- body aches
- fever
- sore throat
- headache
- dry cough
- fatigue
- nasal congestion
INFLUENZA transmission
flu viruses spread in respiratory droplets caused by coughing and sneezing
AIDS (HIV) effect on the body (1)
viral disease
- helper T cells are destroyed (needed for normal immune system function)
AIDS (HIV) transmission (3)
- sexual contact
- contact with contaminated blood or body fluids
- can be passed to babies during delivery or during breastfeeding
CHICKEN POX effect on the body (1)
viral disease
- skin rash of blisterlike lesions
CHICKEN POX transmission (2)
- virus particles are spread in respiratory droplets caused by coughing and sneezing
- highly contagious
HEPATITIS B effect on the body (6)
viral disease
- jaundice (a medical condition with yellowing of the skin or whites of the eyes)
- fatigue
- abdominal pain
- nausea
- vomiting
- joint pain
HEPATITIS B transmission
contact with contaminated blood or bodily fluids
WEST NILE VIRUS effect on the body (3)
viral disease
- fever
- headache
- body ache
WEST NILE VIRUS transmission
bite from an infected mosquito
HUMAN PAPILLOMAVIRUS (HPV) effect on the body
viral disease
- genital or anal warts
- cancer of the cervix, penis, and anus
HUMAN PAPILLOMAVIRUS (HPV) transmission
sexual contact
What is often the best way to protect against most viral diseases?
- vaccines
- wash hands
- avoid contact with sick individuals
- etc.
How can you treat viral diseases?
anitiviral drugs: attack viral enzymes (proteins in capsids) which may help to keep virus in lysogenic (dormant) state
History of Vaccines: 1769
Edward Jenner performs the first inoculation against smallpox, using the less harmful but similar cowpox virus
History of Vaccines: 1880s
Louis Pasteur develops vaccines against anthrax and rabies
History of Vaccines: 1923
Albert Calmette and Camille Guerin develop a vaccine against tuberculosis
History of Vaccines: 1950s
Jonas Salk develops a polio vaccine that uses killed viruses. Albert Sabin develops a polio vaccine that uses weakened viruses.
History of Vaccines: 1981
A vaccine against hepatitis B that uses recombinant DNA gains government approval.
History of Vaccines: 2006
A vaccine against human papillomavirus gains approval.
Why are emerging diseases particularly threatening to human health?
The pathogens that cause emerging diseases are particularly threatening to human health because human populations have little or no resistance to them, and because methods of control have yet to be developed.
What is an emerging disease?
an unknown disease that appears in a population for the first time OR a well-known disease that suddenly becomes harder to control because of evolution
*comes from already existing viruses and bacteria
What is penicillin?
an antibiotic derived from fungi
What did the widespread use of antibiotics lead to?
the process of natural selection that favors the emergence of resistance to these powerful drugs
What are “superbugs”?
bacteria that have evolved resistance to many antibiotics and that transfer drug-resistant genes from one bacterium to another through conjugation
How are new viruses forming?
because viruses replicate so quickly, their genetic makeup can change rapidly, sometimes allowing viruses to “jump” from one host species to another and mutating
ie. AIDS caused by HIV probably evolved from a monkey virus and “bird flu” has been able to affect humans
How are new viruses forming?
because viruses replicate so quickly, their genetic makeup can change rapidly, sometimes allowing viruses to “jump” from one host species to another and mutating
ie. AIDS caused by HIV probably evolved from a monkey virus and “bird flu” has been able to affect humans
Do bacteria inject DNA/RNA into cells? Do viruses?
bacteria: no! if they get into the body, they are around and between cells
viruses: yes! they get into the body and into cells
