Lecture 10: Apicomplexa

diarrhea/dysentery

cryptosporidium parvum disease

Sexual event

An oocyst comes from a

cryptosporidium spp.

what are intestinal coccidian parasites that infect humans/animals?

oocysts

what in stool detected by modified acid-fast staining and DIC microscopy?

Cryptosporidiosis by Cryptosporidium spp.

The most common of the three intestinal coccidia that infect humans is?

Schizogony, gametogony in intestinal/respiratory tract epithelium, sporogony in the host

Coccidian life cycle of cryptosporidiosis

dianostic stage of cryptosporidiosis

dianostic stage of cryptosporidiosis

sporulated oocyst

Infective stage of cryptosporidiosis

Thick walled

Which oocyst gets excreted

Worldwide, esp. daycare; refractory to water purification, outbreaks

epidemiology of cryptosporidiosis

Food, water, person to person (sexual and fecal) , zoonotic

transmission of cryptosporidiosis

diagnosis of cryptosporidiosis

ID of oocysts in stool (concentrated, stained); PCR

Nitazoxanide; no effective treatment in AIDS

Treatment of cryptosporidiosis

toxoplasma gondii, plasmodium spp.

blood and tissue sporozoa

toxoplasma gondii

Typical coccidian parasite - Intracellular parasite, infects many warm-blooded animals, including humans

house cats and other felidae

what are definitive hosts of toxoplasma gondi who produce fecal oocysts?

tachyzoites

within toxoplasma gondii, Mature oocysts contain sporozoites that develop into ______ during acute infection

bradyzoites

within toxoplasma gondii, slow-growing _______ also develop and form cysts in chronic infection

ingestion of raw/undercooked meat containing cysts, ingestion of oocyst from cat feces or fomites, organ transplant or blood transfusion, transplancental transmission, accidental inoculation of tachyzoites

human infection methods of toxoplasma gondii

congenital toxoplasmosis

transplancental transmission of toxoplasmosis gondii?

immunodeficiency

there is reactivation of toxoplasmosis gondii during:

meningoencephalitis, mass lesions and brain abscess

toxoplasmosis gondii can lead to:

ubiquitous

toxoplasmosis has _____ infection

immunocompromised patient with toxoplasmosis

CNS involvement, chorioretinitis, or pneumonitis; acute or reactivated infection!

AIDS patients with toxoplasmosis

reactivation as major cause for encephalitis (ring-enhancing lesions in brain scan)

congenital toxoplasmosis

acute primary infection of mother during pregnancy

spontaneous abortion, stillbirth, or severe disease

first trimester with toxoplasmosis

epilepsy, encephalitis, microcephaly, hydrocephalus, intracranial calcifications, mental retardation, pneumonia, chorioretinitis, etc.

later in pregnancy with toxoplasmosis

serologic testing

what is the routine method of diagnosis of toxoplasmosis?

no treatment for healthy person who is not pregnant or immunocompromised

what is the treatment for toxoplasmosis?

Pyrimethamine plus sulfadiazine (clindamycin, spiramycinfor some patient groups)

what do we treat toxo for pregnant or immunocompromised?

blood parasites of the genus Plasmodium

cause of malaria

plasmodium vivax

Benign tertian or vivax malaria

plasmodium ovale

Benign tertian or ovale malaria

plasmodium malariae

Quartan or malarial malaria

plasmodium falciparum

Malignant tertian or falciparum malaria (worst symptoms and outcomes of the five)

plasmodium knowlesi

Simian malaria or quotidian malaria[zoonotic; in macaques (old-world monkeys)]

plasmodia

are coccidian or sporozoan parasites of blood and tissue cells

mosquito (as host for sexual reproductive stages DEFINITIVE HOST ) and human/animal (as host for asexual reproductive stages)

malaria/plasmodum require two hosts:

Sexual reproductive stages

In malaria, mosquitoes are the host for

Asexual reproductive stages

In malaria, humans and animals are the host for

Sporozoites

Anopheles mosquito inoculates ___ into the human host

Exo-erythrocytic schizogony

Sporozoites infect liver cells and undergo what in Malria

Schizonts

In Malaria what are exo-erythrocytic schizogony matured into

Merozoites

In erythrocytic schizogony malaria, what infects RBCs

Ring stage trophozpites

What matured into schizonts in erythrocytic schizogony

Merozoites

These are released whenever schizonts rupture

Gametocytes

Some parasites differentiate into sexual erythrocytic stages

hypnozoites (sleeper cells)

________ as dormant stages of P. vivax and P. ovale can persist in liver and cause relapses!

Blood stage parasites

What causes the clinical manifestations of malaria and are diagnostic

tropical and subtropical areas and altitudes below 1500 m

where is malaria usually restricted to?

climatic and population changes

distribution of malaria is affected by:

plasmodium vivax

what is the most predominant species of malaria in the world?

P. ovale

primarily in tropical Africa, also in Asia and South America

P. malariae

found in South America, Asia, and Africa, but less prevalent than other species

P. falciparum

frequent in tropical and subtropical regions

P. Knowlesi

in Malaysia, and other countries in SE Asia with macaques as primary host

rapidly fatal

Untreated malaria can progress to severe forms that may be:

paroxyms with malaria

caused by rupture of RBC and release of merozoites

clinical presentation of malaria

what depends on the infecting species, the level of parasitemia, and the immune status of the patient?

p. falciparum

severe, potentially fatal forms with CNS involvement (cerebral malaria), acute renal failure, severe anemia, or acute respiratory distress syndrome due to infarctions

p. falciparum and p. Knowlesi

infect any RBC at any stage of its existence => high parasitemia.

p. vivax and p. ovale

invade only young RBCs, P. malariae only mature RBCs

RBC

P. falciparum has sequestration of infected:

rossette

P. falciparum has what formation?

microinfarcts

within P. falciparum binding of infected RBCs to endothelial cell produces what?

malarial hemoglobinuria

intravascular hemolysis with rapid destruction of RBCs

haemozoin

end product of hemoglobin digestion - makes it totally black

blackwater fever (urine turns black)

Acute renal failure, tubular necrosis, nephrotic syndrome, death

Hb mutations (sickle cell, alpha or beta thalassemia)

increased resistance to malaria (P. falciparum)

duffy antigen

(Fya, Fyb,..) as receptor for P. vivax entry into RBC - Duffy-negative Fy-/Fy- resistance to vivax malaria

G6PD deficiency

increased resistance to P. falciparum invasion

Microscopic Id

What is the method of choice to detect an active malaria infection

molecular diagnosis technique (PCR)

Can compliment microscopy, especially in species identification

Antibody detection

This can detect past malaria infections

P. falciparum

Banana (crescent)-shaped gametocytes

p vivax and p ovale

Numerous pink granules or Schüffner dots - Increased size of RBC

indirect florescent antibody test

Malaria antibody detection using the:

recrudescence (therapeutic)

what is a recurrence of clinical symptoms from low levels of parasites (Plasmodium falciparum, P. malariae) in red blood cells.?

suppressive, therapeutic, radical cure, gametocidal

Treatment strategies for malaria

suppressive

avoid infection

therapeutic

eliminate erythrocytic forms

radical cure

eliminate hypnozoites

gametocidal

distruct gametocytes

p falciparum and p malariae

What type types of malaria are associated with recrudescence

P vivax and p ovale

What type types of malaria are associated with relapses

Chloroquine

Oral drug, toxic to plasmodium, gets into digestive vacuole and inhibits heme polymerization

Primaquine and tafenoquine

Used for radical cure

Primaquine and tafenoquine

What drug would you use to treat p vivax or p ovale

Pregnancy and G6PD

Primaquine and tafenoquine Are contraindicated in

P falciparum

Many of what strains are resistant to chloroquine

Pre-erythrocytic circumsporozoite protein

What do the vaccines for malaria target