Unsporulated oocyst shed in feces

Undergose sporulation to form a sporulated oocysts with sporocysts with 8 sporozoites

Each zoite invades an epithelial cell

sporozoites in epithelial cell grow larger to form a schizont (Schizogony)

Each Schizont produces numerous first generation merozoites these burst the cell and invade other cells

(reapt 2-3 times)

A merozoite can then develop into a male or female gametocyte, fertilization occurs and they make an oocyst

Merozoite produced by final schizogony enters cell and develops into either a male or female gametocyte

Female gametocyte develops into a macrogamont

Male gametocyte (microgamont) undergoes repeated nuclear divisions producing numerous biflagellate microgametes that rupture microgamont

Microgametes enter cells containing macrogametes and fertilize macrogametes and form zygotes

wall forms around zygote to form oocyst

Oocyst released in feces

Dogs and cats

Small intestine; rarely cecum and colon

How many sporocysts does cystoisospora have?

How many sporozoites?

2 sporocysts

each with 4 sporozoites (8 total)

How many sporocysts does Eimeria have?

How many sporozoites?

4 sporocysts

2 sporozoites

Oocyst becomes sporulated within 3-4 days

Cat can ingest oocyst or Mouse can ingest oocyst

If mouse ingests then there is a cyst with 1 zoite in the mesenteric lymph nodes.

Cat eats mouse. Both form zoite in cat tissues which form schizont etc.

Crowding, young

presence of coccidia does not necessarily mean coccidiosis

Disease cuased by sporozoites invading intestinal cells, schizogony, and resulting merozoites

Direct correlation b/w number of coccidia and degree of infection

eroded, bleeding areas of intestine

Acute: Catarrhal enteritis; rarely hemorrhagic

emaciation, weakness, dehydration, rarely fatal

Chronic: Most common scenario: Mild diarrhea

Subclinical: many have coccidia with no clinical signs

Presence of oocysts in fecal flotation

ID to species level not important

Sulfadimethoxine

Trimethoprin/Sulfadiazine

Sulfaguanidine

Amprolium

Clean up feces

steam clean kennels

Must aim to keep host from getting sporulated oocysts

Sarcocystis:

DH:

IH:

DH: Carnivore

IH: Herbivore

Gametogony occurs in SI of canines or felines

Oocysts sporulated in intestine so shed infective sporocysts in feces

Schizogony occurs in herbivores in vascular endothelium

Formation of bradyzoites in sarcocysts in muscle tissue

Dog/cat infected when they eat herbivore with bradyzoites

Zoites liberated and initate gametogony

Not pathogenic in DH

Lots in herbivore (cover in ruminant section)

Recover sporocyst in fecal exam

9-15 x 7-12 um

Toxoplasma gondii

Hosts and geographic distribution

Cats only known DH

Virtually all warm blooded animals can be paratenic hosts

All over NA

Highest in warm, moist, tropical climates

Sporulated oocyst ingested by paratenic host

Tachyzoites and cysts containing bradyzoites

Cat can eat sporulated oocyst or paratenic host

1. Enteroepithelial (cycle only in cats)

2. Extraintestinal (paratenic Hosts... could be cats)

Initially classic coccidian lifecycle:

Schizogony in jejunum and ileum, followed by gametogony with development of oocysts

Oocysts in environment sporulate in 1-5 days

can persist in soil 18 months

infective upon ingestion to all warm blooded animals

After ingestion of sporulated oocysts the sporozoites are released and invade the deep layers of the epithelium and tachyzoites are spread by portal cirulation to liver, lungs, etc

After systemic spread organism may encyst (bradyzoites) and animal enters a chronic or carrier stage

PH can also ingest tachyzoites or bradyzoites

PPP of Toxoplasma gondii if cat ingests bradyzoites?

If cat ingests oocysts or tachyzoites?

3-10 days

3-7 weeks

intestinal infections rarely produce significant pathology

Tachyzoites and bradyzoites produce tissue destruction

abortion

Numerous and varied

Ocular, respiratory, neuromuscular, cardiac, reproductive

ID oocysts in fecal exam of a cat

Small: 9-11 x 11-14 um

Serologic tests

PCR

No approved drugs

Clindamycin

Daraprim

no known treatments for intestinal stages

Prevent carnivorism

feed cats only dry or canned food

change litter boxes daily

ingestion of cysts in undercooked meat

ingestion of sporulated oocyst

organ transplantation or blood transfusion

transplacental transmission

ingestion of unpasteurized goat milk

Cook meat

wash hands

change litter boxes daily

wear gloves while gardening

cover sand boxes

wash hands before eating

pregnang woman= no litter boxes

don't eat raw meat

Distribution of Giardia

Worldwide distribution

Regional differences in prevalence

Most common assemblages of Giardia in dogs ?

Cats?

Dogs: C and D

Cats: F

1. Trophozoite: 9-21 x 5-15 um

Motile, teardrop shaped, flagella, one side shaped into a sucking disc

two nuclei each with large endosome

2. Cyst: 8-12 x 7-10 um

oval, contains two nuclei when passed, resistant and immediately infective

when ingested 2 trophozoites are released

Direct

Ingestion of a cyst

Trophozoites excyst in upper SI

pass into lower small intestine and large intestine... trophozoites form proteins in vacuoles that are released onto surface of trophozoite foriming a protein coat (Encystation)

cysts passed out in feces

6-8 days

cysts can survive for weeks in h20 or moist environment

Block absorption in intestine (lots of trophozoites)

deficiency of digestive enzymes

toxins interefere with activity of enzymes

excessive mucous secretion

bacterial overgrowth

villous atrophy

***NOT BLOODY DIARRHEA***

Highly variable: None to severe diarrhea

weight loss

flatulence

dry skin and poor hair coat

Direct smear of a fresh sample is only way to observe trophozoites

use ZnSO4 flotation with centrifugation

Elisa (detects encystation antigen)

shedding is intermittent so may need to check more than one fecal

No approved treatments

Fenbendazole

Drontal Plus

Bathe on day of last treatment

prevent fecal contamination of feed and water

disinfection

treat asymptomatic carriers

Tritrichomonoas foetus

Host and geographic distribution:

3 flagella anteriorly

1 posterior flagellum

10-20um long, 5-10um wide

similar to giardia trophozoite

occurs in ileum, cecum, colon and rectum

no cyst stage

Little known

inflammation in colon produces enteritis

eosinophilic colitis

mucosal crypt cell necrosis

Low bowel diarrhea

malodorous, flatulence

may contain blood and mucus

dribbling of feces

diarrhea may last 2 days to 3 years

Direct smear of fresh feces with fecal loop

hard to differentiate from giardia trophs

PCR

Many treatments tried, fecal improves but diarrhea returns after discontinued

treatments may prolong course of disease

Ronidizole