public health

Question 1

methods of transmission

Answer 1

• respiratory
  fecal oral
  parenteral (blood/body fluids - neddle stick injury
• sexual
  fomites - blanket, clothing.
  arthropod
  vertical - thru germ line. placental infection, infection in birth canal.

Question 2

what 6 things help microorganism survive in hostile enviro?

Answer 2

multiple antimicrobial resistance
tough cell wall or capsule or envelop (easier to spread with cell wall = better resistance)
phagocytosis
intracellular pathogen
production of exotoxins
adaptation to enviro.

Question 3

immunization - caveats. impediments

Answer 3

caveat - doesnt work for everyone. immune suppressed individuals cant mount the response
impediment - controversial topic.

Question 4

ex: rubella.

infection during pregnancy

Answer 4

infection during early pregnancy = congenital rubella syndrome (CRS) = miscarriage, microphthalmia, chorioretinitis, deafness.
earlier infection more fatal.

Question 5

public health: water testing

Answer 5

detect fecal bacteria, parasite, virus.
pH sets acceptable limits for amount of fecal coliforms in drinking water - marker for contamination. rather than looking for 1 infectious bacteria look for its overarching group.

Question 6

what are fecal coliforms?

Answer 6

classification of bacteria that are gram negative and that dont make spores.

Question 7

control of indirect transmission in water

Answer 7

chlorination (some organisms resistant) and filtration

Question 8

public health: food testing

• bacteria, virus, parasite detection
• samples tested?
• other food related public health initiatives

Answer 8

detect presence of fecal bacteria, parasite, virus.
bacteria: isolation and PGFE (gel electrophoresis = DNA fingerprint.
virus= detect and genotype
parasite = detect and ID
- collect food/water, feces from infected person.
educate regarding proper food handling.

Question 9

public health: vector control

Answer 9

eradicate or prevent insects/vectors from contacting susceptible persons. : insecticides, rat patrol, mosquito net.

Question 10

vector control ex: madagascar

Answer 10

yersinia pestis. carried by small mammals and fleas.

treatment: isolated madagascar from outside world.

Question 11

public health: contact tracing

Answer 11

ID, isolation and treatment of infected person

ID transmitting cluster and intervene to prevent additional transmission.

Question 12

detection and diagnosis

ex: HIV - how it affects the body.

Answer 12

2 strains - 1 worldwide, 2 west africa.
viral target = CD4 on monocytes.
virus gets into host DNA. when DNA replicates so does virus = lot of virus floating around cell and body. gets into monocyte/macrophage and migrates to lymph nodes where infection can be dispersed thru whole body.
infection is opportunistic

Question 13

controlling spread of HIV

Answer 13

EIA = enzyme immunoassay - detect antibodies and antigens specific to HIV infection.
then do other immunoassay to determine strain.
do NAT - nucleic acid test to measure amount of HIV-RNA in blood. – confirmation of initial infection and treatment monitoring

Question 14

monitor viral load

Answer 14

using NAT - determine how much viral substance present. good to do for babies borne to HIV-positive mothers

Question 15

HIV - test limitations

Answer 15

some tests no longer used because detection time is too long due to lower specificity and selectivity.
3rd gen = can detect in 50% of ppl within 22 days
4th gen = detect antibody and antigen. detect withing 15-20 days.
want to decrease window of detection.

Question 16

define seroconversion

Answer 16

when individual changes from HIV Ab (-) to HIV Ab (+)

Question 17

acute HIV

Answer 17

uncontrolled viral replication, high levels f virus in bloodstream.

Question 18

chronic HIV

Answer 18

period of latency. lack of symptoms/signs. slow replication. destroy immune system - opportunistic.

Question 19

identification of resistance transmission - gonorrhea

• what does this mean?
• why?

Answer 19

neisseria gonorrhea = increased resistance and treatment failur.
new forms of anitmicrobial resistance in this virus.
probably due to unrestricted access to microbials, overuse of antibiotics, suboptimal quality of anitbiotics, inherent genetic mutations in infectiours organism

Question 20

3 requirements for pandemic flu

Answer 20

1. new influenza virus subtype emerges
2. infects human and cause serious disease
   3 . spread eacily and is sustainable among humans.