L25 Protozoa Intracellular indirect Life Cycle | Parasitology Exam 3

What are the intracellular protozoa w indirect life cycle

1. Toxoplasma

2. sarcocystis

3. Neospora

What are the definitive hosts of Toxoplasma gondii

cats

What are the natural IH of Toxoplasma gondii

mice

Which spp are accidental, dead-end or IH of toxoplasma

rumimants

humans

How many sporozoites are in each sporocyst in Toxoplasma gondii oocysts

1 oocyst (after 24hr) = 1 sporocyst = 4 sporozoites

Which host ingest sporocyst of Toxoplasma gondii and what does it result in with Toxoplasma gondii stage

IH ingests sporocysts that invade gut macrophages to form tachyzoites

For the life cycle of Toxoplasma gondii, where are Tachyzoites carried to after gut macrophage development, and what do they form

Tachyzoites carried to blood and lymph nodes to form bradyzoites

How does Toxoplasma gondii bradyzoites eventually begin sexual reproduction from tissue

bradyzoites remain in tissue cysts until cat (DH) ingests them to go to intestinal tract and begin sexual reproduction

When the IH are infected during pregnancy, the predilection site for Toxoplasma gondii multiplication is what

placenta

Where does Toxoplasma gondii tachyzoites from ingested oocysts penetrate in host (and then what occurs after penetration)

Penetrate host cells and multiply asexually

Where does Toxoplasma gondii bradyzoites penetrate in host (and then what occurs after penetration)

bradyzoites penetrate brain and muscle cells causes dz

When there is a toxoplasma infection during early pregnancy in cattle, What are the results

• embryonic death

• reabsorption of fetus

When there is a toxoplasma infection during mid pregnancy in cattle, What are the results

fetal death followed by mummificiation due to compromised placental nutrition or fetal infection

When there is a toxoplasma infection during late pregnancy in cattle, What are the results

abortion of a dead calf/lamb

birth of a weak calf/lamb

In toxoplasmosis in cattle, what occurs to the aborted hosts

aborted hosts remain normal

In toxoplasmosis in cattle, what occurs to the placenta

cotyledons are autolytic w small white multifocal areas of necrosis and calcification

What are the CS of DH and IH in toxoplasma

DH - asymptomatic

IH - abortion

What are the four dx for toxoplasma

• qPCR - polymerase chain rxn

• direct microscopic examination

• tissue biopsy

• serological tests

With dx testing of toxoplasma, what does direct microscopic examination reveal

sporocysts in feces of DH

With dx testing of toxoplasma, what does tissue biopsy reveal

demonstration of tachyzoites or bradyzoites in tissue samples of IH

With dx testing of toxoplasma, what does Serological tests reveal

recent active infection → IgM antibodies

past exposure → IgG antibodies

What are the three tx meds for felines in toxoplasmosis

• clindamycin

• pyrimethamine

• doxycycline

What are the two tx meds for cattle in toxoplasmosis

• sulfonamides

• decoquinate

What are the two tx meds for humans in toxoplasmosis

• pyrimethamine

• sulfadiazine

What are the major mental problems associated w toxoplasma

• schizophrenia

• humans 3x more likely to be involved in car accidents

• lower intelligent tests

What are control/prevention strategies to prevent spread of toxoplasma in terms of sanitation (inc. cat litter)

• wash hands

• wash vegs

• wash utensils

• cook meat properly

• pregnant women should be careful

• cat litter should be cleaned daily

Why were southern sea otter in California coast being infected w toxoplasma (and prevention)

cat litter w T. gondi oocysts were flushed into storm drains

prevention → new bill passed to prevent T. gondii

What are the DH of Neospora caninium ( and the common name of Neospora caninium)

dogs and other canids

parasite of neurological tissues/hindlimbs of dogs

What is the IH of Neospora caninium

cattle (#1 cause of abortion in cattle)

What parasite is the #1 cause of abortion in cattle

Neospora caninium

How do canids become infected w Neospora caninium (and what are the relevant time periods for infection in adult canids that cause neosporosis)

canids ingest cattle tissue containing bradyzoites → during pregnancy or immune-compromising condition cause neosporosis

How do adult cattle become infected w Neospora caninium

ingestion of sporulated oocysts in dog’s fecal-contaminated feed or water

What does cogenital infection of Neospora caninium in dogs and cattle result in

disseminating active tachyzoites across the placenta

What is the route of infection for Neospora caninium during pregnancy and the cause

transplacental infection caused by ingestion of oocysts during pregnancy

What are the CS of Neospora caninium in adult dogs

• encephalomylitis (inflammation of brain and spinal cord)

• nodular dermatitis and ulcers

• pneumonia

• weight loss

How does neosporosis in adult dogs occur

• pregnancy

• immune-compromising condition

What are the CS of Neospora caninium in pups

• begin hind limb paralysis at 3wks of age

• polyradiculitis (disorder of peripheral nerves)

• progessive ascending hindlimb paralysis

What are the CS of Neosporosis in cattle and newborn calves

• abortion occurs btwn 4-8 mo of gestation

• abortion storms are common

→ mummification

→ stillborn

What are the Clinical DX of DH and IH of neosporosis

DH (caninds) → neurological symptoms

IH (ruminants) → abortion

What are the four dx for Neosporosis

1. direct microscopic examination

2. tissue biospy

3. serological tests

4. PCR polymerase chain rxn

What are tx drugs for canids of active infection of Neosoporosis

• clindamycin

• trimethoprimsulfadiazine

What are tx drugs for cattle of active infection of Neosoporosis

• diclazuril

• decoquinate

What spp are the DH of Sarcocystis

• dogs

• cats

• possums

• humans

What spp are the IH of Sarcocystis

• sheep

• cattle

• horses

What is the DH/IH of Sarcocystis neurona and predilection site

DH: possum

IH: horse

predilection site - brain/spinal cord

In the life cycle of Sarcocystis, which host has formation of sarcocysts in tissues

IH

In IH of Sarcocystis, where does formation of sarcocysts occur

in tissues

This image of esophagus is indicative of what definitive dx

Sarcocystis

Each sarcocyst (from sarcocystis infection) contains what and its function in infection

each sarcocyst contains bradyzoites, infective form of carnivore host

What are the CS of sarcocoystosis in ruminants

• MOF

• neurological dz

• limb paralysis in 6-12mo lambs

What are the CS of S. neurona in horses

• equine protozoal myleoencephalitis (EPM)

• muscle atrophy/cranial nerve signs including paralysis

• facial paralysis (VII), head tilt (VIII), Tongue paralysis (XII), Dysphagia (IX,X)

• asymmetric posterior including ataxia

What are clinical dx of sarcocystosis in DH and IH

DH - asymptomatic

IH - neurological signs

What are the four dx for sarcocystosis

1. direct microscopic examination

2. tissue biospy

3. serological tests

4. PCR polymerase chain rxn

What is the tx of sarcocystosis in cattle

amprolium in acute phase

What is tx of sarcocystosis in horses w EPM

• ponazuril

• diclazuril

What should occur w dead livestock due to sarcocystosis

buried or incinerated