[04.15] Blood Flagellates V2.2.pdf

Protozoan parasite

General type of parasite that blood flagellates belong to

. Order Kinetoplastida

Order of blood flagellates

. Family Trypanosomatidae

Family of blood flagellates

. Trypanosoma and Leishmania

Genera belonging to the Family Trypanosomatidae

. Amastigotes

Hemoflagellate stage that does not contain a flagellum

. Promastigotes, Epimastigotes, and Trypomastigotes

Hemoflagellate stages that possess a single locomotory flagellum

. Kinetoplast

DNA-containing organelle present in all four hemoflagellate forms, located close to the flagellar basal body

. Undulating membrane

Structure present in epimastigotes and trypomastigotes

. Leishmanial form or Leishman-Donovan body

Old name for the amastigote form

. Leptomonad form

Old name for the promastigote form

. Crithidial form

Old name for the epimastigote form

. Trypanosome form

Old name for the trypomastigote form

. Trypanosoma cruzi

Etiologic agent of South American Trypanosomiasis

. Chagas Disease

Another name for South American Trypanosomiasis

. 10 million people

Approximate number of people worldwide affected by T. cruzi

. Latin America

Geographical region where T. cruzi is endemic, including Central America and the Southern cone of South America

. Humans

Definitive hosts for T. cruzi

. Armadillos, opossums, raccoons, woodrats, rodents, domestic dogs

Examples of mammals that serve as reservoir hosts for T. cruzi

. Triatomine bug

Arthropod vector commonly used by trypanosomes

. Trypanosomes

General group of parasites that commonly use the triatomine bug as a vector

. Triatoma, Rhodnius, and Panstrongylus

Genera of common triatomine vector species for trypanosomiasis

. Amastigote

Proliferative stage of T. cruzi

. 1.5 to 4.0 micrometers in diameter

Approximate size of T. cruzi amastigotes

. Muscle tissues

Location where T. cruzi amastigotes are usually found in small groups of cyst-like collections

. Bloodstream Trypomastigote

Diagnostic stage of T. cruzi

. C-shaped, S-shaped, or U-shaped

Possible forms of T. cruzi trypomastigotes

. Very prominent and large

Description of the kinetoplast in T. cruzi trypomastigotes

. Posterior to the nuclei (subterminal location)

Location of the kinetoplast in the T. cruzi trypomastigote form

. Trypomastigote

Stage of T. cruzi that has a very pointed posterior end, differentiating it from other trypanosomes

. Epimastigote

Proliferative stage of T. cruzi

. Anterior to the nucleus

Location of the kinetoplast in the epimastigote form of T. cruzi

. Metacyclic trypomastigote

Infective stage of T. cruzi, found in the feces or stool left by the triatomine bug

. Feces/stool

Medium through which the infective stage of T. cruzi is transferred to the host

. Reticuloendothelial cells (specifically macrophages)

Cells usually invaded by the metacyclic trypomastigotes near the site of inoculation

. Binary fission

Method by which amastigotes multiply inside macrophages/tissue

. Bloodstream Trypomastigote

Stage of T. cruzi that does not replicate outside of a cell or vector

. Epimastigote

Stage T. cruzi transforms into in the midgut of the triatomine bug

. Metacyclic trypomastigote

Stage T. cruzi differentiates into in the hindgut of the triatomine bug

. Kissing bugs or Reduviid bugs

Other names for Triatomine bugs

. Family Reduviidae, Subfamily Triatominae

Taxonomic family and subfamily of the triatomine bug vector

. Cheek

Area where the triatomine bug has a propensity to bite, leading to the name "kissing bug"

. Acute phase and chronic phase

Two phases into which American Trypanosomiasis can be divided

. Chagomas

Nodular lesions or furuncles that may develop around the vector's feeding sites in the acute phase of Chagas disease

. Romana’s sign

Chagoma on the eyelids, presenting as palpebral and periocular firm swelling

. Indeterminate form

Chronic phase of Chagas disease that is subclinical or asymptomatic

. Cardiac or digestive forms

Forms of chronic Chagas disease that 30-40 percent of infected individuals develop

. Two positive different serologic methods for Chagas disease, absence of symptoms, normal ECG, and normal radiologic examination of chest, esophagus, and colon

Criteria for the indeterminate form of chronic Chagas disease

. Determinate form

Symptomatic chronic phase of Chagas disease, occurring years or decades after initial infection

. Heart, esophagus, and colon

Organs most commonly involved in the determinate form of chronic Chagas disease

. Dilated cardiomyopathy, megaesophagus, and megacolon

Manifestations resulting from amastigote invasion of smooth muscle in the determinate form of chronic Chagas disease

. Fibrotic reactions

Pathological consequence in the determinate form that causes injury to the nervous system, leading to loss of tone

. Incomplete or complete right bundle branch block (RBBB), left anterior fascicular block (LAFB), minimal ST-T changes, monomorphic premature ventricular contractions (PVCs)

Possible presentations of cardiomyopathy in chronic Chagas disease

. Southern cone of South America (Argentina, Bolivia, Chile, South Peru, Paraguay, parts of Brazil)

Region where the digestive form of T. cruzi infection affects more people

. Achalasia, dysphagia, odynophagia, chest pain, regurgitation, cough

Possible presentations of Megaesophagus

. Chronic constipation, obstruction, volvulus

Possible presentations of Megacolon

. Approximately 5 percent

Prevalence of congenital Chagas disease in children born from chronically infected mothers in endemic areas

. Hypotonicity, fever, hepatosplenomegaly, anemia

Symptoms of congenital Chagas disease apparent at birth or within weeks after delivery

. Myocarditis, meningoencephalitis, pneumonitis

Conditions infants with congenital Chagas disease may present with

. Before one year of age

Timeframe in which etiological treatment is highly effective in congenital Chagas disease

. Complete Patient History

Primary tool to diagnose Chagas disease, establishing the possibility of exposure to T. cruzi

. Acute phase

Phase of Chagas disease during which microscopic identification of parasites is used for diagnosis

. Thick and thin blood smears stained with Giemsa

Blood smears used for microscopic identification of T. cruzi

. Bloodstream trypomastigotes

Diagnostic stage of T. cruzi to focus on identifying in microscopy

. Equal to RBC size (1:1 ratio)

Size of T. cruzi trypomastigotes relative to red blood cells

. Chronic phase

Phase of Chagas disease during which serologic testing is more beneficial for diagnosis

. Two different serologic tests

Minimum number of tests that should be utilized for diagnosing chronic Chagas disease

. EIA (Enzyme immunoassay) and Immunoblot (TESA)

Two first-line serologic tests for chronic Chagas disease

. Immunofluorescence assay (IFA)

“Tie-breaker” test used if the second EIA and TESA testing results are discordant

. Molecular studies using PCR

Test used to identify the presence of T. cruzi DNA

. Acute or early infection phases

Phases of Chagas disease during which anti-parasitic drugs are effective

. Negativization of previously positive serologic test (negative seroconversion of PCR results)

Most common surrogate to establish cure for chronic Chagas disease

. Benznidazole and Nifurtimox

Two main anti-parasitic drugs used for Chagas disease

. Pro-drugs

Description of the anti-parasitic drugs for T. cruzi that activate once within the reticulo-endothelial cells

. Benznidazole Evaluation for Interrupting Trypanosomiasis Trial

Meaning of the acronym BENEFIT Trials

. 5 mg/kg per day in 2 or 3 divided doses for 60 days

Normal adult dosing regimen for Benznidazole

. 8-10 mg/kg per day in 2 or 3 divided doses for 60 days

Pediatric dosing regimen for Benznidazole

. Allergic dermatitis, peripheral neuropathy, anorexia, weight loss, insomnia

Common side effects of Benznidazole

. Nitroimidazole derivative

Drug class of Benznidazole

. 10 mg/kg per day in three divided doses for 60 days

Normal adult dosing regimen for Nifurtimox

. 51 mg/kg per day in three divided doses for 60 days

Pediatric dosing regimen for Nifurtimox

. Nitrofuran compound

Drug class of Nifurtimox

. Gastrointestinal side effects and central & peripheral nervous system toxicity

Common side effects associated with Nifurtimox

. Fexinidazole, Triazole derivatives (antifungals), and GNF6702

Other potential drugs for T. cruzi treatment

. Ergosterol

Biosynthesis blocked by Triazole derivatives (antifungals)

. GNF6702

Azabenzoxazole compound that acts as an allosteric proteasome inhibitor

. Interrupting transmission

Focus of prevention strategies for Chagas disease

. Examining blood smears

One method of screening for malaria

. Trypanosoma brucei (subspecies gambiense, rhodesiense)

Etiologic agent of Human African Trypanosomiasis (HAT)

. African Sleeping Sickness

Another name for Human African Trypanosomiasis

. Biting flies of the genus Glossina (Tsetse fly)

Vector that transmits T. brucei

. Salivarian trypanosome

Classification of T. brucei based on its mode of transmission

. Sub-Saharan Africa

Geographical area where HAT is endemic

. T. brucei gambiense

Etiologic agent of West African Trypanosomiasis

. T. brucei rhodesiense

Etiologic agent of East African Trypanosomiasis

. West African Trypanosomiasis

Form of HAT that accounts for approximately 95 percent of cases

. East African Trypanosomiasis

Form of HAT that accounts for approximately 5 percent of cases

. G. palpalis group

Main vector for T. brucei gambiense

. Humans

Primary reservoir for T. brucei gambiense

. G. morsitans group

Main vector for T. brucei rhodesiense

. Cattle and wild animals

Primary reservoirs for T. brucei rhodesiense