Parasitology II.
Judit Szabó MD. Ph.D.
2010.
Sporozoa
Toxoplasma
Isospora
Cryptosporidium
Plasmodia
Protozoa
Flagellata (Zoomastigophora)
Amoeba (Lobosea, Sarcodina)
Sporozoa (Apicomplexa)
Ciliata (Ciliophora)
Isospora hominis, Isospora
belli
Isospora oocyst in different mature stages
the infection usually symptomless
in immuncompromised patients: diarrhea, abdominal pain, loss of
weight
the source of infection contaminated food or water with oocyst
Life cycle of Isosopora
Diagnosis and treatment
Diagnosis:
demonstration of oocyst from
stool
Treatment:
sulfonamide+ trimethoprim
1
Cryptosporidium
Life cycle of
Cryptosporidium
usually symptomless or mild diarrhea
in immuncompromised:
diarrhea, abdominal
pain, loss of weight
malabsorption syndrome
Plasmodia
Diagnosis and treatment
Diagnosis:
demonstration of
oocyst from the stool
by Kinyoun acid fast
stain
Treatment:
only in
Immuncompromised
paromomycin
Malaria
more than 200 million people worldwide have malaria
more than 1 million people die of it each year
the timing of the fever cycle is:
72 hours for P. malariae (quartan malaria)
P.
P.
P.
P.
vivax
ovale
malariae
falciparum
Geographical distribution of
malaria
48 hours for others (tertian malaria)
malignant tertian malaria: P. falciparumAnopheles (female) mosquito
benign tertian malaria: P. vivax, P. ovale
2
Life cycle of plasmodia
Protective factors
sickle cell anaemia
lack of Duffy blood group antigen
G6PD deficiency
thalassemia
Parasitemia
P. vivax, P. ovale : relatively low-grade
parasitemia (invade only young red blodd
cells)
P. malariae: relatively low-grade
parasitemia (invades only old red blood
cells)
P. falciparum: very high-grade parasitemia
(invades red cells of all ages, including the
erythropoietic stem cells in bone marrow)
Cerebral malaria
Clinical symptomes
periodic fever attack (40 C or more) with
initial chills, lasting from 15 min to 1 hour,
nausea, vomiting, headache are common,
finally sweating
the fever subsides, patient falls asleep and
later awakes feeling relatively well
P. falciparum pyrexia may last 8 hours or
longer
splenomegaly, hepatomegaly, normocytic
anemia
Diagnosis
Giemsa-stained thick
and thin smears
Thick smear: screen
for presence of
plasmodium
Thin smear: identify
the species
3
Treatment
Geographical distribution of
chlorocquin resistance
chlorocquin (merozoites)
primaquin (hypnozoites)
mefloquin (chlorocquin resistant strains)
quinine+doxycycline (chlorocquin
resistant strains)
atoquone+proguanil /malarone/
(chlorocquin resistant strains)
Chemoprophylaxis
Starting 2 weeks before arrival,
continuing for 6 weeks after departure:
1x chlorocquin (300 mg)/ week,
followed by 2 weeks primaquine
Chloroqiune-resistant areas: 1x Fansidar
(500 mg sulfadoxin+ 25 mg
pyrimethamin)/week or
1 x Malarone/week
Life cycle of B. coli
Ciliata
Balantidium coli
Clinical symptomes
usually asymptomatic
chronic recurrent diarrhea alternating
with constipation
there may be bloody, mucoid stool,
tensemus (may mimic sever intestinal
amebiasis)
4
Diagnosis and treatment
Diagnosis:
demonstration of
trophozoites or cysts
from stool
Treatment:
tetracycline followed by
metronidazole if
necessary
General details
3 stages:
egg
larva
Helminthes
Plathyhelmintes
Roundworms
Tapeworms
(Cestoda)
Flukes
(Trematoda)
Tapeworms (Cestoida)
adult worms
in intermediate hosts worms in the larval stages are
found
in final (definitive) hosts worms occur in adult (mature)
stage
all tapeworms are hermaphrodites
worms consist of 2 main parts:
head: scolex
multiple segments: proglottids
Flukes (Trematoda)
Taenia saginata (beef tapeworm)
Taenia solium (pork tapeworm)
Hymenolepis nana (dwarf
tapeworm)
Diphyllobotrium latum (fish
tapeworm)
Echinococcus (dog tapeworm)
Dipylidium caninum
Taenia saginata and solium
Fasciola hepatica
Schistosoma
Paragonimus westermani
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Scolex of Taenia solium
Scolex of Taenia saginata
Proglottids of Taenia
saginata
Life cycle of Taenia
Scolex and proglottids of
Taenia solium
Clinical symptoms
ingestion of cysticerci:
symptomless or diarrhea
ingestion of egg (only T. solium):
human cysticercosis (muscles, brain,
eye)
6
Cysticercus of Taenia
Diagnosis and treatment
Diagnosis:
demonstration of proglottids (eggs)
from the stool
Treatment:
praziquantel
Diphyllobotrium latum
Scolex and proglottids of
Diphyllobotrium latum
Life cycle of Diphyllobotrium
latum
Clinical symptomes
symptomless or diarrhea, abdominal
pain
megaloblastic anaemia
7
Diagnosis and treatment
Hymenolepis nana
Diagnosis:
demonstration of the
egg from the stool
Treatment:
praziquantel
Life cycle of Hymenolepis
Clinical symptomes
symptomless or diarrhea
Diagnosis and treatment
Diagnosis:
demonstration of eggs
from the stool
Echinococcus
Echinococcus granulosus (dog tapeworm): unilocular hydatid cyst
Echinococcus multilocularis (fox tapeworm): multiloculated cyst
Treatment:
praziquantel
8
Life cycle of Echinococcus
Clinical symptomes
symptomless
or according to the localisation:
-alteration with liver function
-bloody sputum
-neurological signs headache
Echinococcus cyst in the
liver
Echinoccus cyst in the liver
Diagnosis and treatment
Dipylidium caninum
Diagnosis:
serological reactions
(ELISA, indirect
hemagglutination)
Treatment:
surgical, albendazole
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Scolex of Dipylidium
caninum
Proglottids of Dipylidium
caninum
Life cycle of Dipylidium
caninum
Clinical symptoms
symptomless
abdominal pain
diarrhea
perianal itching
Diagnosis and treatment
Diagnosis:
demonstration of
proglottids from the stool
Treatment:
niclosamide
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