Final Exam - Protozoal

Question 1

Plasmodium Sp.
(Trans+Inc.+Diag)

Answer 1

(Malaria)

Transmission: Mosquito bite from anopheles mosquitos

Incidence: In tropical areas. Not many in US, all due to travel. Increasing amounts. Most fatalities in children under 5, pregnant women, and immunocompramised pts. New vaccine with 75% efficacy in clinical trials.

Diagnosis: Symptoms of fever, headache, chills, rigors, joint/muscle pain. Confirmed by tests like blood smears and microscopy. Rapid tests exist. Cerebral malaria has high mortality rate. High cyclic fevers.

Question 2

Malaria species

Answer 2

Plasmodium

falciparum: most pathogenic (~50% of all infections)

vivax: rarely lethal, has liver involvement, more common in Asia. Can be dormant and relapse in mother.

ovale: more common in W. Africa

malarium: uncommon

Question 3

Trichomonas vaginalis
(SSS+Trans)

Answer 3

(Trichomoniasis)

SSS: vaginitis in women and urethritis in men. Can be asymptomatic in women, but usually copious, thin, frothy, foul-smelling discharge that is yellow or gray as well as increase in vaginal pH. Distinguishable by microscopy.

Transmission: Sex

Question 4

Giardia
(Spe.+SSS+Trans)

Answer 4

(Beaver fever)

Species: duodenalis, lamblia

SSS: chronic diarrhea with greasy, foul smelling stools (malabsorption of fat and carbs) that lasts for 1-2 weeks but as long as 6 weeks. Causes sever intractable diarrhea in AIDS pts.

Transmission: Intestinal with natural reservoir in small mammals. Acquired by drinking unsterilized water containing cysts in mountain streams.

Question 5

Cryptosporidium parvum
(SSS+Trans)

Answer 5

(Cryptosporidiosis)

SSS: Mild to moderate diarrhea in health ppl. Famous case in Milwaukee - 400,000 infections. Severe chronic diarrhea in AIDS pts and leading cause of “bowel disease” and wasting syndrome.

Transmission: Acquired through contaminated drinking water. Natural reservoir of farm animals like cows, sheep, and goats.

Question 6

Entamoeba histolytica
(SSS+Incidence)

Answer 6

(Amebic dystentery)

SSS: diarrhea (intestinal amebiasis), but can get into bloodstream and result in liver abscess.

Incidence: throughout the world, high prevalence in tropic areas.

Question 7

Pneumocystis juroveci (carinii)
(SSS+Mech+Trans)

Answer 7

SSS: cough, SOB, severe tachypnea, dyspnea, chest pain, cyanosis. 10-20% of AIDS deaths. If untreated, 90-100% lethality. Drugs cure 65% of cases.

Mechanism: single cell organism as cystic and extracystic form. Opportunistic seen in immunosuppressed pts.

Transmission: Widely spread, most of the pop has antibodies by age 4.

Question 8

Toxoplasma gondii
(SSS+Mech+Trans+Notes)

Answer 8

(Toxoplasmosis)

SSS:
toxoplasmic encephalitis - (headache, altered mental status, motor weakness, speech disturbances, seizures)
Acute infections - lymphadenopathy with fever, night sweats, malaise, sore throat, macupapular rash. diffcult to distinguish from mono. symptoms resolve in a few months.
Immunodeficient pts. - CNS infections, brain lesions, also heart infections.

Mechanism: obligate intracellular protozoa. exists as tachyzoites, in cysts, and oocysts. Be in any organ.

Transmission: Widely distributed in nature, Cat is definitive host. OOcysts are shed in cat feces.

Notes: Cause of chorioretinitis in US as result of congenital infection from mother - blurred vision, pain, photophobia, loss of central vision - asymptomatic till later in life. Women should avoid cat litter although transmission is low - eyes CNS (retardation seizures), hearing loss.