infectious diseases Flashcards
disease
condition in which body doesn’t function normally and produces symptoms
what are infectious diseases caused by
pathogens (microorganisms such as: bacteria, virus, fungi, protists)
transmission
movement of pathogen from an infected to an uninfected
vector
organism that transmit a pathogen from one person to another
Cause of cholera
bacterium vibrio cholerae
transmission of cholera
1) enters body through food and water
2) breed in small intestines —> secrete toxin that reduces ability of the epithelium of intestine to absorb salt and water into blood
3) loss in feces
how to prevent transmission of cholera
1) treating sewage effectively
2) providing clean water supply
3) maintain good hygiene in food preparation
cause of malaria
protoctist, plasmodium
4 main species of plasmodium
1) plasmodium falciparum (!)
2) plasmodium malariae
3) plasmodium ovale
4) plasmodium vivax
where does plasmodium infects
red blood cells
how to prevent transmission of malaria
- reducing population of mosquitos
- releasing large numbers of sterile males —> decrease in female’s reproductive potential
- preventing mosquitos from biting people
- prophylactic drug (prevents pathogens from infecting and breeding)
cause of tuberculosis
1) mycobacterium tuberculosis
2) mycobacterium bovis
transmission of tb
- inhalation of airborne droplets of liquid
- drinking unpasteurised milk
how to prevent transmission of tb
- increasing standards of living
- treating HIV infections
- BCG vaccination (immune to tb)
- drug therapy (prevents HIV-positive person to get tb)
- antibiotics
HIV/AIDS
human immunodeficiency virus
How is HIV spread in the body
1) HIV attaches to CD4 cell receptor to enter host cell
2) HIV enters CD4 cell —> RNA turns to DNA (enzyme reverse transcriptase)
3) HIV multiply inside
4) HIV leaves CD4 cells to infect more cells
transmission of HIV
- sexual contact
- shared needles
- occupational exposure
- breast feeding
- blood transfusion
how to prevent transmission of HIV
- blood used in transfusion should be screened
- hypodermic needles should be only used once and sterile
- sticking to one partner
- practice protected sex
- drugs (only prolong life span)
antibiotic
substance that kills bacteria, but doesn’t harm human cells (not effective against virus)
how does antibiotic work
- destroys cell wall of bacteria causing them to burst
- stopping protein synthesis and production of nucleic acids
why doesn’t antibiotics work on viruses
virus contains a protective protein coating which cannot be attacked like the cell wall of bacteria
penicillin
- prevents the synthesis of peptidoglycan molecules and the cell wall
- water enters the cell by osmosis —> increases pressure —> cell wall bursts
rifampicin
inhibits enzyme used for RNA synthesis in bacteria
tetracycline
binds to bacterial ribosomes and inhibits protein synthesis
