FM 3 Exam 2

Question 1

ABC’s of STDs to prevent their spread

Answer 1

Abstinence
Barrier protection
Contacts
Drug therapy
Education and counseling

Question 2

pathogens that can facilitate transmission of HIV (7)

Answer 2

1. chlamydia trachomatis
2. neisseria gonorrhoeae
3. bacterial vaginosis
4. HSV 1 & 2
5. treponema pallidum
6. haemophilus ducreyi
7. klebsiella granulamatis

Question 3

10 warning signs of primary immunodeficiency

Answer 3

1. 4+ ear inf in 1 yr
2. 2+ serious sinus inf in 1 year
3. 2+ months on abx w/ little effect
4. 2+ PNA in 1 yr
5. failure of an infant to gain weight or grow normally
6. recurrent, deep skin or organ abscess
7. persistent thrush in mouth or fungal inf on skin
8. need for IV abx to clear inf
9. 2+ deep seated inf (incl septicemia)
10. family history of PI

Question 4

types of hosts for parasites

Answer 4

definitive host = parasite sexual stage occurs in it
intermediate host = parasite development or non-sexual reproduction occurs in it
incidental host = it isn’t needed for parasite life cycle

Question 5

transmission modes for parasites

Answer 5

direct: replicating form from one host to another
ingestive: non-dividing or dormant cyst or egg that is ingested from food or environment
invasive: active but non replicating form directly penetrates skin
vector: non replicating form transmitted ia arthropod
mother to in utero fetus

Question 6

what is a vector?

what are the 2 types?

Answer 6

host species that directly transmits infectious form of parasite to another host species
biological = req’d in parasite life cycle
phoretic = no req’d for parasite life cycle

Question 7

when does a domestic physician need to think about parasites?

Answer 7

1. pt going to travel abroad
2. pt returning from abroad
3. pt born in endemic area
4. immunocompromised

Question 8

cysticercus

Answer 8

encysted cestode larval form found in tissues of infected intermediate hosts
aka: bladder worm
found in humans infected w/ tapeworm (taenia solium)

Question 9

cyst hydatid

Answer 9

specialized cysticercal form of custody Echinococcus granulosis found in intermediate host (sheep, human, wild ungulates)

Question 10

cercaria

Answer 10

highly motile trematode larval form released from intermediate host
either directly infectious for definitive host (schistosomes) or must first encyst on/in 2nd intermediate host (tissue fluke)

Question 11

Sporozoa (phylum apicomlexa) shared features (5) and members of the group (4)

Answer 11

1. obligate intracell parasites
2. apical intracell organelles involved in host cell invasion
3. alternate be asexual (schizogony) and sexual (sporogamy) reproduction
4. sex cycle occurs in intestinal epithelium of definitive host
5. all stages are haploid, except for the zygote, which is diploid
   Members: cryptosporidium, toxoplasma, babesia, plasmodium

Question 12

what substitution do all chloroquine resistant strains of plasmodium falciparum contain?

Answer 12

lysine to threonine substitution at amino acid 76 (K76T)