export_circulatory parasites Flashcards
Organism that causes African sleeping sickness
Trypanosoma brucei
Vector for Trypanosoma brucei
Tsetse fly
Early stage of sleeping sickness
Organisms in blood and peripheral lymph nodes
Fever, myalgia, chills, lymphadenopathy
Late stage of sleeping sickness
Invasion of CNS
Headaches, seizures, tremors, encephalitis, coma, death
Diagnose sleeping sickness
Detection of parasites in blood smears, lymph node aspirates, or CSF
Trypanosoma brucei immune evasion
Ag variation
Organism that causes Chagas’ disease
Trypanosoma cruzi
Vector for Trypanosoma cruzi
Reduvid bug
Transmitted by fecal material
First sign of Chagas’ disease
Romana’s sign - development of chagoma
Acute phase of Chagas’ disease
Fever, malaise, myalgia, hepatosplenomegaly
Indeterminate (asymptomatic) phase of Chagas’ disease
Few parasites in blood, but high level of Ab
Chronic stage of Chagas’ disease
Infection of cardiac muscle/myenteric plexus
Cardiac and GI involvement
Diagnose Chagas’ disease
Parasites in peripheral blood (acute)
Serology (chronic)
Organisms that cause visceral Leishmaniasis
L. donovani
L. infantum
L. chagasi
Vector for Leishmaniasis
Female sand flies
Visceral Leishmaniasis disseminates in which system?
Reticuloendothelial (liver, spleen, bone marrow, etc.)
Initial presentation of Leishmaniasis
Low grade, irregular fever
Most infections are asymptomatic and resolve
Symptoms of full-blown Leishmaniasis
Fever, weight loss, hepatosplenomegaly
Systemic immunosuppression, opportunistic infections
What does resolution of Leishmaniasis depend on, and why?
CMI via gamma-IFN activation of macrophages, because only intracellular forms of the pathogen (amastigotes) are found in infected individuals
Organisms causing malaria
Plasmodium spp.
What four spp. of Plasmodium cause malaria in humans?
P. falciparum
P. vivax
P. malariae
P. ovale
First two are most common
Vector for malaria transmission
Mosquitos
Characteristic clinical feature of malaria
Malarial paroxysm - release of merozoites and hemolysis
Flu-like symptoms
Duration and pattern of paroxysm based on organism (malaria)
P. vivax, ovale, and falciparum - 48 hours
P. malariae - 72 hours
Three stages of malaria
Cold stage (15-60 mins) Hot stage (2-6 hours)
Sweat stage (8-12 hours)
Most common complication of malaria
Anemia
RBC lysis, suppression of erythropoiesis, destruction of RBCs by spleen
Targets of each malaria organism
P. falciparum - both young and mature RBCs
P. vivax - young RBCs, must bear Duffy Ag
P. ovale - young RBCs, Duffy positive or negative
P. malariae - older RBCs
Which malaria organism causes the most severe anemia?
P. falciparum
Which malaria organisms can remain dormant in the liver for years?
P. vivax
P. ovale
Diagnose malaria
Clinical syndrome
Travel Hx
Blood smear for parasites
Characteristic feature of P. falciparum
“Purple banana”
Organisms causing babesiosis
Babesia spp.
Vector for Babesia spp. transmission
Ticks
Characteristic feature of babesia infection
“Maltese cross”
Babesiosis symptoms
Most infections are asymptomatic
Fever, chills, myalgia, hemolytic anemia
Organisms causing filariasis
Wuchereria bancrofti and Brugia malayi (nematodes)
Vector for filariasis transmission
Mosquitoes
Symptoms of filariasis
Many are asymptomatic
Acute infection begins with fever, chills, and lymphadenitis
Only small percentage develop “elephantiasis”
Diagnose filariasis
Observation of microfilariae in blood smears
Treatment for filariasis
DEC kills microfilariae and damages adults
Steroids counteract allergic response to dying worms
Organisms causing schistosomiasis
Schistosoma spp.
Different species that cause schistosomiasis and where they infect
S. mansoni - venous plexus of L.I.
S. japonicum - venous plexus of S.I.
S. haematobium - venous plexus of bladder
Diagose schistosomiasis
Eggs in feces or urine
Intracellular stage for sleeping sickness
None
Intracellular stage for Chagas’ disease
Skeletal and cardiac muscle cells
Intracellular stage for Leishmaniasis
Macrophages
Intracellular stage for malaria
RBCs, hepatocytes
Intracellular stage for babesiosis
RBCs