Acanthocephalans And Protozoa Flashcards
Describe the morphology of the acanthocephala
Long cylindrical nose with retractable probiscus. Probiscis is covered in spines which allows attachment organelles.
Has males and females.
Absorb nutrients by their body surface
How many eggs are laid by an adult acanthocephala per day
1/4 million per day
Describe the egg of the acanthocephalan
Contains a larval form. Unique shape with three shells.
Describe the lifecycle of the acanthocephalan
Ingestion of egg by arthropod intermediate host. Egg hatches in the intermediate host and develops into a stage with an inverted proboscis (acanthella). The intermediate host is ingested and the proboscis everts which allows for attachment to the intestine
What is the oncicola canis
Lives in small intestine, the proboscis can perforate the intestinal wall and cause peritonitis.
What is the intermediate host for oncicola canis
Dung beetle
How do you diagnose oncicola canis
Fecal flotation.
Describe protozoa
Most protozoa are free living organisms that are Uni cellular and motile. Mostly microscopic and into forms a cyst or a trophozoite
How are protozoans classed in their phylla
Based on their movement style: Flagellates Amoebae Ciliates Apicomplexans
Describe flagellates
May come in two forms. At least one flagellum in the trophozoites form which allows for movement. They live in liquid: blood, lymph, CSF. Tear drop and pear shaped.
What are some flagellate pathogens
Trichomonas
Giardia
Trypanosoma
How do amoeba move
By pseudopods
What are the two forms that amoebas come in
Trophozoite form and cystic form
What is an example of an amoeba pathogen
Entamoeba histolytica: causes dysentery
What does it mean if you see two nucleus in a cystic form of an amoeba
It is immature. Four nucleus is the adult
What are ciliates
Covered by cilia. Creates their movement and the dart and twirl.
What are the two types of nuclei in ciliates
Macro and micro
What are APicomplexans
Important cost in veterinary medicine do to their complicated lifestyles. Banana or boomerang shape
What are some examples of apicomplexans
Toxoplasma, plasmodium (malaria), eimeria (coccidiosis in LG animals), cystoisospora, cryptosporidium
Describe the phylum acanthocephala
Thorny headed worm. Most marine and freshwater fish, aquatic birds. In the small intestine
What are some general facts about giardia ?
Infect 41 species.
Direct cycle
Occur in two forms
Where is giardia located
In the intestinal mucosa and may or may not cause physical damage
What are the two forms of giardia
Trophozoites and cysts
Describe the cyst form of giardia
Contain 4 nuclei.
What is characteristic of an animal affected with giardia
Greasy, white, mucus due to lypolosis
What is the pathology of giardia
Compete with host for food. Irritates intestinal cells by its adhesive disk and interferes mechanically with nutrient absorption. Causes excessive mucus production. Secretes toxins that interfere with enzymatic activity.
Describe the giardia life cycle
Cysts are ingested
Cause excystation in duodenum
Drop off mucosal surface and encyst and is immediately infective
What is the PPP for giardia in dogs
6-8 days
What is the PPP for giardia in cats
1-2weeks
How many trophozoites are in one cyst
Two trophozoites
Describe the cysts of giardia
Survive in the environment for months. Resist freezing and bleach
How do you destroy giardia cysts
Boiling water
Describe the zoonotic potential of giardia
You can get it from cats and dogs but humans generally get it from other humans by drinking/eating food and water contaminated with cysts
How do you diagnose giardia
Through a fresh smear with saline and water. You will only see the form in fresh stool less than 30 mins old.
You can also do a floatation with zinc sulfate for giardia cysts.
Why is it difficult to diagnose giardia
Because the trophozoites are rare and intermittently shed
What is cystoisospora
Coccidia. Has a direct cycle and is an intracellular parasite of intestinal epithelium.
What are the symptoms of coccidia
Asymptomatic or bloody/ mucus stools.
What is the life cycle of cystoisospora
Oocytes are in feces
The Oocytes sporulate in the environment and after a few days the sporolated form is infectious.
What is the PPP for cystoisospora
7 days
How do you diagnose cystoisospora
Flotation
How do we treat cystoisospora
By symptom. Immune system is working if it is asymptomatic
Describe cryptosporidium
Direct cycle. It is coccidian like and not intracellular. It is on the surface of the intestinal epithelium.
How do you develop cryptosporidium
Ingestion of sporulated oocysts
What are th symptoms of cryptosporidium
Diarrhea
How do you diagnose cryptosporidium
Elisa tests
Flotation or fresh smear and stains.
Describe the Zoonotic potential of cryptosporidium
Water is the #1 mode of transmission.
Most frequent causes of waterborne disease among humans in the United States
Describe sarcocystis
Indirect cycle. From ingestion of muscle of pigs, horses and ruminants. There are many species of sarcocystis and each has a different intermediate host.
How do you diagnose sarcocystis
By fecal flotation.
Who is the definitive host for toxoplasma gondii
The cat
Who is the intermediate host for toxoplasma gondii
Humans and 300 others.
Which animals have a higher resistance to toxoplasma gondii
Horses and cows
Which animals are a high risk for toxoplasma gondii if you consume them
Chicken and lamb.
What is the greatest source of infection with toxoplasma gondii
Uncooked meat and unpasteurized milk.
Describe toxoplasmosis
Zoonosis but most cases are benign except for immunocompromised patients and pregnant patients.
If you are seropositive for toxoplasma gondii what does that mean
You have been exposed and have antibodies.
What is special about toxoplasma in terms of IH
Can be a direct or indirect life cycle
What are the symptoms of toxoplasma gondii
Destroys cells and causes necrosis. Most infections are never detected or diagnosed.
When do you diagnose toxoplasma
In immunocompromised cats
What are some symptoms of toxoplasma in immunocompromised cats
Focal or generalized lymphadenitis, encephalitis, pneumonitis, myocarditis and retinochoroiditis
Describe the oocyst infectious form of toxoplasma gondii
Only shed in the feces by the fat over a period of 10-14 days. Infectious form is sporulated in 1-5 days post shedding in ideal conditions (20-38*c and high humidity)
How many infectious forms of toxoplasma are present in each egg
8 infectious forms per egg
After a cat has previously been infected with toxoplasma, will the shed oocysts on the second infection ?
No unless they are suffering from a debilitating disease
How can toxoplasma oocysts contaminate the environment
The soil or fruits/vegetables in the garden
What are the bradyzoite form of toxoplasma
Slowly dividing encysted tissue stages found in all warm blooded vertebrate hosts
What are tachyzoites
In milk, saliva or sperm, blood.
Rapidly dividing tissue stages found in all vertebrate hosts.
Describe the entero-epithelial cycle of toxoplasma in cat
Ingestion of infected mammal or avian tissue (bradyzoites)
Release of forms which penetrate intestinal cells
The cycle starts over again (a few generations) - the PPP 3-15 days.
What can the entero-epithelial cycle of cats cause
Diarrhea but mostly normal feces.
Describe in general the entero-epithelial cycle of toxoplasma in cats
Break a cell, go back in, go into sexual reproduction and make oocysts.
Describe the extra-intestinal cycle of toxoplasma
Occurs in all species.
Both cycles can occur simultaneously in cats.
Ingestion of oocysts- release of sporozoites. Eventually become tachyzoites that are rapidly dividing. Rupture and invade surrounding cells.
Can cross the placental barrier into fetus.
Tachyzoites become bradyzoides within 3-4 days post infection. They can persist for years
What happens if a mom is infected in the first trimester with toxoplasma
It’s difficult for the tachyzoites to invade but they can cause a lot of damage
What can happen to a mom if she is infected with Toxoplasma in the second or third trimester
It is easy for the tachyzoites to invade but it is difficult for it to cause damage
At what point does the Bradyzoide of toxoplasma reactivate in the animal
If the animal becomes pregnant or immunocompromised
What are the three sources of infection for toxoplasmosis in decreasing order of importance
Intermediate hosts in food: ingestion of Bradyzoites.
The soil: ingestion of oocysts.
The cat: ingestion of oocysts.
How long does it take for the oocysts of toxoplasma to become infectious
1-5 days
If I cat is infected with toxoplasmosis how long will it shEd oocysts
2 weeks
If a cat is infected with toxoplasmosis can he shed oocysts more than once in his life?
No. Unless he is fiv/felv
If a cat is shedding toxoplasma oocysts, how was he infected ?
Bradyzoide cyst is eaten (uncooked meat/ate a mouse)
What are three ways to minimize risks for toxoplasmosis
Clean the litter box once per day, keep your cat indoors, don’t feed your cat raw meat
What are two flagellates of cats and dogs
Trypanosoma cruzi (causes sleeping sickness)
Leishmania (from sand flies)
What transmits babesia canis and what is it considered
Tick bite. Apicomplexans
What does babesia canis cause
Anemia, jaundice, fever, hemoglobinemia, hemoglobinuria and weakness
What are the three common apicomplexans of cats and dogs
Babesia canis
Cytauxzoon felis
Hepatozoon
How is cytauxzoon felis transmitted
By Tick bite
How is hepatozoon transmitted
By ingestion of tick
