tissue protozoa

Question 0

toxoplasmosis

Answer 0

• caused by toxoplasma gondii from CAT feces, oocytes in SOIL, undercooked LAMB, PORK.
• in immunocompetent: nontender LN enlargement, sometimes hep, myocarditis, myositis. NO TX REQUIRED
• in IC: MULTIFOCAL ENCEPHALITIS (FATAL UNTX)
• if its chronic infection –> give you cysts that are PAS+,
• dz terminates when cell-mediated defenses kick in. however, can establish latent infection and reactivate when lower defenses.
• congenital infection: transplacental transmission causes NECROTIZING MENINGOENCEPHALITIS, lose brain parenchyma, CEREBRAL CALCIFICATIONS, HYDROCEPHALUS, CHORIORETINITIS. if born –> MR, subtle psychomotor defect and visual impairment. TX: antiprotozoal

ONE OF THE TORCH (PRENATAL INF)
TOXOPLASMOSIS, OTHER, RUBELLA, CMV, HSV2

Question 1

what are the 4 tissue protozoas?

Answer 1

1. toxoplasmosis
2. leishmaniasis
3. chagas dz
4. sleeping sickness

Question 2

leishmaniasis

Answer 2

• leishmania sp that comes from infected SANDFLY BITES that targets and x in macrophages and bursts and reinfect.
• sx depends on species and immune status:
  1. LOCALIZED CUTANEOUS LEISHMANIASIS –> ulcerating disorder = “oriental/tropical sore”, “leishman-donovan bodies”
  2. mucocutaneous leishmaniasis: L. braziliensis
  3. Visceral leishmaniasis: kala azar, potentially fatal infection of monocyte/macrophage system.

initial infections like #1. can reactivate years later and cause destruction = “tapir nose deformity”

Question 3

chagas dz

Answer 3

• caused by trypanosoma cruzi (zoonatic) thats in reduviid (kissing) bug that infects humans (feeds on sleeping humans)
• causes systemic inf in humans –> GI and HEART, BRAIN CELLS
• CHAGOMAS: nodular infl lesion, if gets into blood –> progressive destruction of HEART, ESOPHAGUS (megaesophagus), COLON (megacolon)

-can cause fatal myocarditis, cardiac failure, GI dz YEARS AFTER INITIAL INFECTION.

Question 4

sleeping sickness

Answer 4

• african trypanosomiasis; trypanosoma brucei: blood sucking flies Glossina)
• LIFE THREATENING MENINGOENCEPHALITIS - tremors of fingers and toes, fasciculations, speech abn, cerebellar signs.
• 2 types:
  1. trypanosoma brucei gambiense (chronic, >1yr)
  2. trypanosoma brucei rhodesiense (DIES quick, 3-6mos)

each wave of circ trypomastigoes incl. different antigen variants in genetically determined pattern:

1) primary chancre –> papillary swelling w. central red spot
2. systemic infection (winterbottom sign - enlargement of cervical node)
3. brain invasion