Parasites Pt 2: Trypanosoma + Schistosoma

Protozoan hemoflagellates

Trypanosoma Genus are parasites defined as __ __

Sub-Saharan Africa, cattle

Trypanosoma brucei

• Geographic region - __ __ __

  • Zoonotic infection also infects __ (animal)

Tsetse fly, humans, trypansomes, extra

Trypanosoma brucei

• Definitive Host - The __ __ (vector for transmission)

• Intermediate Host - __/mammals

  • Antigenic variation of surface glycoprotein on __ → Immune evasion

  • __cellular growth - Reproduces by cell division

Single, trypanosomes, neuropsychiatric, sleepiness

T brucei in human host

• __-celled protozoan lives in blood, lymphatics, and interstitial spaces between cells

• Pathology associated with site of accumulation of __

• Can accumulate in brain → __ and __ symptoms

African Sleeping Sickness

Pathogenesis of Trypanosoma brucei

Fly bite, trypomastigotes, antigenic, perivascular infiltration, demyelinating encephalitis

African Sleeping Sickness from T brucei

• (1) Site of __ __ - Local inflammatory lesion/nodule within few days

• (2) __ spread into blood and lymphatics - parasitemia waxes/wanes based on __ variation

  • Sx → Recurrent bouts of fever, rash, headache, lymphadenopathy

• (3) __ __ into organs and across blood brain barrier

  • Leads to __ __ sx - altered cognition, convulsions, coma, and death

Demyelinating encephalitis sx

Altered cognition, convulsions, coma, and death (resultant of advancing African sleeping sickness)

Trypomastigotes, M, fly, fatal

T brucei Dx and Prevention

• Dx - Microscopic examination of blood smear for __, Ig_ in blood/CSF

• Prevention - Control of __ populations; untreated is __

Mexico, Central and South America

Trypanosoma cruzi

Geographic region - (3)

Triatomine bug, humans

Trypanosoma cruzi

• Definitive Host - __ ___ (vector for transmission)

• Intermediate Host - __

Blood, intra, phagocytosis, adaptive, auto-immune

T cruzi in human host

• Initial infection - Dissemination via __ and invasion of cells

• Parasite grows __cellularly inside cells of various tissues and organs

• Taken up by __ → Escapes phagolysosome and multiples in cytoplasm

• Induces inflammation and __ immune responses

• Some indication that anti-parasite immune response may include __-__ -like responses

Chagas Disease

Pathogenesis of Trypanosoma cruzi

Asymptomatic, chagoma, parasitemia

Chagas Disease  - Acute disease

• Potential for __ infection

• __: Nodule and or inflamed lesion at site of insect bite

• __ sx - Fever, hepatomegaly, splenomegaly, lymphadenopathy, transient rash, malaise, potential myocarditis

Lifelong, subset, conduction, colon, esophagus, immunocompromised

Chagas Disease  - Chronic disease

• Often asymptomatic for decades - __ infection

• Sx occur in small __ of infected individuals

  • Cardiomyopathy, cardiomegaly, dysrhythmias → __ effects

  • Mega__ and mega__ → dysphagia and constipation

• Reactivation of acute infection possible in __

8 weeks, chronic

Chagas Disease

Without tx, parasitemia of T cruzi falls and acute sx resolve over _ __ → Then progression to resistant __ phase

Antibody, blood, acute, fly, transfusions

Dx and Tx of T cruzi

• Dx - __ serology, parasites seen in __ in acute stage

• Tx - Anti-parasitics useful during __ infection, an early dx important

• Prevention - Control of __ populations, monitor __ (procedure) in endemic regions

Animal kingdom, worms

All schistosoma species are part of the __ kingdom, Adults are small __

Humans, venules, eggs, aquatic snails

Schistosoma species

• Definitive Host - __

  • Schistosoma in human host reside in __ (vessels)

  • Produce __ that accumulate and lead to pathology

• Intermediate Host - Several __ __

Eggs, aquatic snails, cercariae, Schistosoma worms, small intestine, bladder

Schistosoma Life Cycle Steps

1. Seeding of __ into freshwater

2. Eggs hatch penetrate __ __ (intermediate host) for asexual reproduction

3. Snails eventually release __ into water

4. Adult __ __ migrate through blood to veins and venules

5. Eggs then migrate to __ __ or __

Eggs, aquatic snails, cercariae, skin, liver, Schistosoma worms, veins/venules, 5, small intestine, bladder, antigens

Schistosoma Life Cycle

• Seeding of __ into freshwater - urine or feces (from human, animals)

• Eggs hatch penetrate __ __ (intermediate host) for asexual reproduction

• Snails eventually release __ into water

• Cercariae penetrate human __ entering water and enter circulation

  • Migrate to and mature to Schistosoma worms in __

• Adult __ __ migrate through blood to __/__ around intestine and liver

• Worms live _+ years - deposit eggs in batches

• Eggs migrate to __ __ or __

  • Adult worms use immune evasion tactics - coat themselves in host __

Katayama Syndrome

Initial infection that is systemic hypersensitivity for few weeks after Schistosoma infection

Katayama Syndrome initial sx

Fever, urticaria, angioedema, chills, myalgia, diarrhea, headache from Schistosoma

(initial vs chronic)

Katayama Syndrome Chronic Infection

Host damage due to eggs and immune response to eggs from Schistosoma

(initial vs chronic)

ulceration, portal hypertension, ascites, ulceration, scarring, brain, spinal cord

Chronic Infection with Katayama Syndrome

• Bladder - Inflammation, __

• Liver - Periportal fibrosis and __ __, hepatomegaly, __

• Bowel - Inflammation, __, blood loss and __

• CNS - Rare serious infection of the __ and __ __

Eggs, freshwater, snail

Schistosomiasis Dx and Prevention

• Dx - Identifying __ in stool or urine

• Prevention

  • Avoid swimming/bathing in __ (environment) high risk area

  • Reduce __ populations