PARA (Book) Flashcards
Documented in Egyptian and Chinese writing in 2700 BC.
Plasmodium spp.
is the major species associated with deadly infections through- out the world
Plasmodium falciparum
cause 95% of infections of plawmodium
P. vivax and P. falciparum
Responsible for 80% of the remaining
infections.
P. vivax
Malaria parasite of long-tailed macaque monkey.
P. knowlesi
Distribution:
Tropics, subtropics, and temperate zones
P. vivax
Distribution:
Tropics
P. falciparum
Distribution:
Sporadically distributed
P. malariae
Distribution:
Central West Africa and some South Pacific Islands
Limited to tropical Africa, the Middle East, Papua New
Guinea, and Irian Jaya in Indonesia
P. ovale
Distribution:
Malaysian Borneo, Thailand, Myanmar, and Philippines
P. knowlesi
Cycle:
Female Anopheles mosquito (vector) w/ sporozoites in
salivary glands is discharged into the punctured wound.
Pre-Erythrocytic cycle
Cycle:
Within 1 hour the sporozoites carried by the blood to the liver
will penetrate hepatocytes
Pre-Erythrocytic cycle
Cycle:
Initiating the pre-erythrocytic or primary exoerythrocytic cycle
Pre-Erythrocytic cycle
Cycle:
Sporozoites become round or oval and divide.
Pre-Erythrocytic cycle
Cycle:
Schizogony results in large numbers of exo-erythrocytic
merozoites
Pre-Erythrocytic cycle
Cycle:
Merozoites leave the liver and invade the RBC
Pre-Erythrocytic cycle
Species in which dormant schizogony may occur
which remain quiescent in the liver.
P. vivax and P. ovale
Called resting stages are known ___________ and
lead to a true relapse often within 1 year or up to
more than 5 years later
hypnozoites
RBCs and reticulocytes have been invaded, the parasites
grow and feed on _______
hemoglobin
Cycle:
Within the RBC, the merozoite (or young
trophozoite) is vacuolated, ring-shaped, more or
less amoeboid, and uninucleate
ERYTHROCYTIC CYCLE
Once the nucleus begins to divide, the trophozoite is called a
developing
Schizont
The mature schizont contains _______ (the number
depends on the species), which are released into the
bloodstream
merozoites
Cycle:
Merozoites are destroyed by the immune system. Others
invade RBCs and initiate a new cycle of erythrocytic
schizogony
ERYTHROCYTIC CYCLE
After several erythrocytic generations, some of the merozoites
begin to undergo development into the
Gametocytes
Plasmodium spp. stages:
Sporozoites →Merozoites (Schizogony) OR Hypnozoites
(Ovale and Vivax only) → Young trophozoites → Merozoites
(Schizogony) → RBC burst → [Repeat RBC invasion] →
Gametocytes
Benign tertian malaria
PLASMODIUM VIVAX
Infects only the reticulocytes thus parasitemia is limited.
P. vivax
Limited to 2-5% available RBCs.
P. vivax
Splenomegaly occurs during the _______ weeks of infection.
P. vivax
First
P. vivax second dormant schizogony occurs in ____
liver (hypnozoites)
50% of patients infected may relapse after weeks, months, or >5
years.
P. vivax
Morphology:
Enlarged young RBCs with Schuffner dots (James
stippling) — Small, round, red granulations
P. vivax and P. ovale
Developing rings are ______ in P. vivax
amoeboid
P. vivax mature schizont has
12-24 merozoites
Signs and Symptoms:
Headache, photophobia, muscle aches, anorexia, nausea, and
sometimes vomiting.
P. vivax
Death and coma to px with primaquine resistance
P. vivax
changes mental status and if untreated may result in fatality within 3 days
Acute cerebral malaria
Similar P. vivax but less severe
P. ovale
Tends to relapse less but may occur after weeks, months or >1 year
P. ovale
Developing rings are less amoeboid than those of P. vivax
P. ovale
Mature schizont of P. ovale __ merozoites
8
Human infections with ________ are associated with a
higher level of parasitemia
variant-type P. ovale
Incubation period of P. malariae ranges from ____ (longer than ovale and
vivax).
27-40 days
A regular periodicity is seen from the beginning, with a more severe
paroxysm:
Cold stage — Longer stage.
Hot stage — More severe sx.
Sweating stage — Collapse is common
P. malariae
Spontaneous recovery may occur or recrudescence (recurrence of sx).
P. malariae
Morphology:
RBCs may have fimbriated edges
Developing rings tend to demonstrate “band” forms.
Mature schizont contains an average of 6-12 merozoites
P. malariae
P. malariae contains an average of ____ merozoites
6-12
_____ is common and the infection may be associated with
nephrotic syndrome in P. malariae
Proteinuria
P. falciparum other term
Malignant Tertian Malaria
Schizogony occurs in the spleen, liver, and bone marrow rather than in the circulating blood
P. falciparum
Causes cytoadherence (feature in severe malaria)
P. falciparum
Morphology:
The RBCs are all sizes.
NO true stippling
Maurer dots may be present.
Multiple rings are present (delicate w/ 2 dots of chromatin)
Gametocytes are crescent shaped
P. falciparum
Ring forms identified within the marginal regions of the erythrocytes of P. falciparum are called
Accole or applique forms
Onset of P. falciparum ___ after infection
8-12
complication causing red blood cell lysis, hemoglobin release, discoloration
Blackwater fever
Rare complication with high parasitemia, pulmonary edema, anemia, cerebral and renal complications
Disseminated intravascular coagulation (DIC)
Plasmodium knowlesi other term
SIMIAN MALARIA, THE FIFTH HUMAN MALARIA
Invades all ages of RBCs, with a higher number of infected cells compared to P. vivax, P. ovale, and P. malariae.
P. knowlesi
Early blood stages of P. knowlesi resemble
P. falciparum
Mature blood stages of P. knowlesi and gametocytes resemble
P. malariae
Morphology:
RBCs of all sizes
Absence of true stippling
Multiple rings per RBC and delicate rings with 2-3 dots of chromatin
Band forms with developing trophozoites
Mature schizont with 16 merozoites
P. knowlesi
Characteristics:
48-hour cycle
Tends to infect young cells
Enlarged RBCs
Schüffner dots (true stippling) after
8-10 hours
Delicate ring
Very amoeboid trophozoite
Mature schizont contains
12-24 merozoites
P. vivax
Characteristics:
72-hour cycle (long incubation period)
Tends to infect old cells
Normal size RBCs
No stippling
Thick ring, large nucleus
Trophozoite tends to
form “bands” across
the cell
Mature schizont contains 6-12 merozoites
P. malariae
Characteristics:
48-hour cycle
Tends to infect young cells
Enlarged RBCs with fimbriated edges (oval)
Schüffner dots appear in the beginning
(In RBCs with very young ring forms, in contrast to P. vivax)
Smaller ring than P vivax
Trophozoite less amoeboid than that of p. vivax
Mature schizont contains an average of 8 merozoites
P. ovale
36-48—hour cycle
Tends to infect any cell regardless of age, thus may heavy infection may result
All sizes of RBCs
No Schüffner dots (Maurer dots: may be larger, single dots, bluish)
Multiple rings/cell (only young rings, gametocytes, and occasional mature schizonts are seen in peripheral blood)
Delicate rings, may have two dots of chromatin/ring, appliqué or accolé forms
Crescent-shaped gametocytes
P. falciparum
24-hour cycle
Tends to infect any cell regardless of age; thus very heavy infection may result
All sizes of RBCs, but most tend to be normal size
No Schüffner dots (faint, clumpy dots later in cycle)
Multiple rings/cell (may have 2 to 3)
Delicate rings, may have 2 or 3 dots of chromatin/ring, appliqué forms
Band form trophozoites commonly seen
Mature schizont contains 16 merozoites, no rosettes
Gametocytes round, tend to fill the cell
Early stages mimic P. falciparum; later
stages mimic P. malariae
P. knowlesi
Stain recommended for parasitic blood work, but other stains like Wright’s, Wright-Giemsa, or Rapid Field stain can also be used
Giemsa Stain
________ and the quantitative buffy coat (QBC) method can be used for rapid screening and detection of malaria organisms.
Fluorescent nucleic acid stains
________ preferred for thin- and thick-smear microscopic films; proper blood-anticoagulant ratio is crucial.
Blood collected with EDTA
Rapid malaria tests (RMTs) use monoclonal antibodies against ________ or _________, or detect species-specific parasite lactate dehydrogenase (pLDH).
histidine-rich protein 2 (HRP2) or Plasmodium aldolase
Gold standard for malaria diagnosis remains the examination of _____________ due to sensitivity limitations in patients with low parasitemia
thick and thin blood films
The number of white blood cells per microliter of blood is compared to the number of organisms
Result reporting:
In thick film quantitation
Parasitemia is reported as the percentage of infected red blood cells in total erythrocytes, excluding extracellular parasites
Result reporting:
Thin smear quantitation
Kills tissue schizonts
Tissue schizonticides
Kills blood schizonts
Blood schizonticides
Kills gametocytes
Gametocytocides
Prevent the formation of sporozoites within the mosquito
Sporonticides
_____ widespread except in Central America and the Caribbean.
Artemisinin combination therapy
The cause of most human infections in the United States (5%). Occur in non splenectomized individuals and are relatively mild.
B. microti
Washington, Oregon, and California.
Tend to be more serious and mimics B. divergens.
B. duncani and alike organism
Common in Europe (40%) and is often found in splenectomized patients, and causes a more serious form of the disease.
B. divergens
Similar to Plasmodium spp. but without an exoerythrocytic stage.
Babesia
Babesia in RBC, trophozoites reproduce by _______ rather than schizogony
Binary fission
Diagnostic tetrads seen in babesia
Maltese cross
Mild causes of B. microti is treated with:
Clindamycin
Quinine
Atovaquone
Azithromycin
Hemoflagellate protozoa that live in the blood and tissue of the human host
Trypanosoma spp.
primary area of endemic infection with T. brucei gambiense (West African trypanosomiasis) coincides with the vector _______ belt through the heart of Africa
tsetse fly
300,000 to 500,000 people may be infected in Western and Central
T. brucei rhodesiense
East African
Trypanosoma brucei rhodesiense
Organism:
Trypanosoma brucei rhodesiense
East African
Vector of East African Trypanosomiasis
Tsetse fly
Glossina morsitans group
Animals are the primary reservoirs
East African Trypanosomiasis
Acute (early CNS invasion)
East African Trypanosomiasis
Epidemiology:
Anthropozoonosis
Game parks
East African Trypanosomiasis
Recommended Specimen for East and West African Trypanosomiasis
Chancre aspirate
Lymph node aspirate Blood
CSF
Diagnostic stage of trypanosomiasis
Trypomastigote
Multiplication of trypanosome takes place in
salivary glands
Trypanosome:
Granular cytoplasm stains
Pale blue
Trypanosome:
Centrally located nucleus
Kinetoplast stains
Reddish
Organism for West African Trypanosomiasis
Trypanosoma brucei gambiense
Vector of West African Trypanosomiasis
Tsetse fly
Glossina palpalis group
Primary reservoir for West African Trypanosomiasis
Humans
Illness:
Chronic
(late CNS invasion)
months to years
West African Trypanosomiasis
Epidemiology:
Anthroponosis
Rural populations
West African Trypanosomiasis
Long, mild, chronic course that ends in death with central nervous system invovlement after years
West African Sleeping Sickness
Short coarse and ends fatally within 1 year
More rapid, fulminating disease than does T. brucei gambiense
East African Sleeping Sickness
toxic trivalent arsenic derivative, for blood and CNS stages but not recommended for treatment of late sleeping sickness
Melasporol
used for more than 10 years for melarsoprolresistant T. brucei gambiense infection with or without CNS involvement
Eflornithine (dl-alpha-difluoromethylornithine; DFMO)
zoonosis occuring throughout the American continent and involves reduviid bugs/ kissing bugs (vectors)
Chaga’s disease
Causative organism for american trypanosomiasis
Trypanosoma cruzi
Trypanosoma rangeli
Primary reservior of Trypanosoma cruzi
Opossums
Dogs
Cats
Wild rodents
Primary reservoir of T. rangeli
wild rodents
Recommended specimen for T. cruzi
Blood
Lymph node aspirate
Chagoma
Specimen for Trypanosoma rangeli
Blood
ingested by the reduviid bug (triatomids, kissing bugs, or conenose bugs) as it obtains a blood meal.
Trypomastagotes
Trypomastagotes transform into
epimastagote
Epimastagote multiplies in
bug’s midgut (posterior
“most neglected diseases” – based on its association with poverty and on the limited resources
Leishmaniasis
2nd in mortality and 4th in morbidity among all tropical diseases
Leishmaniasis
An intracellular parasite in the cells of the reticuloendothelial system
Oval-shaped
Measures 1.5 to 5 um
Contains nucleus and kinetoplast
AMASTIGOTE
As the vector takes a blood meal, promastigotes are introduced into the human host.
Parasites move from the bite site to the organs within the reticuloendothelial system (bone marrow, spleen, liver) or to the macrophages of the skin or mucous membrane
Promastigote
Untreated primary lesions may develop into the mucocutaneous form in up to 80% of the cases.
Dissemination to the nasal or oral mucosa may occur from the active primary lesion or may occur years later after the original lesion has healed.
Mucocutaneous Leishmania
Incubation period of visceral leishmaniasis
10 days -2 years (2-4 months)
