Parasitology exam 2 review - pt 3 (Protozoans?)

What is a protozoa?

Unicellular, or one-celled, organisms.

What are the 3(4) phyla in Kingdom Protista that cause the most significant pathology? How do they differ? 

Sarcomastigophora (1: Flagellated protozoans and 2: ameboid protozoans), (3) apicomplexans, and (4) ciliated protozoans.

These phyla differ in the manner in which the protozoans move within their tiny microenvironments. In veterinary parasitology, the most important phyla are Sarcomastigophora (containing the flagellates and amoebae), Ciliophora (containing the ciliates), and Apicomplexa (containing the coccidia, malarial organisms, and piroplasms).

What are the Flagellates? 

The flagellates are those protozoans that possess at least one flagellum (a long whip-like or lash-like appendage) in their trophozoite, or moving form. This flagellum allows the protozoan to move about in a fluid medium. As a result of this activity, parasitic flagellates live in the liquid world of the host’s blood, lymphatic fluid, or cerebrospinal fluid. Flagellates are often pear shaped or bullet shaped and are able to swim in their host’s body fluids, meeting very little resistance

What are the different protozoans in the flagellates of dogs and cats?

Giardia species, Trypanosoma cruzi (Blood), Leishmania species (blood),

What are the Amoebaes?

The amoebae are protozoans that move via pseudopodia (“false feet”). Amoebae have two forms: the motile trophozoite form and the resistant cyst form. In their motile trophozoite form, amoebae glide or flow along a solid surface, usually the surface at the bottom of the liquid medium. Amoebae are amorphous (poorly defined, or blob-like, in shape). 

What are the different protozoans in the Amoebas of dogs and cats?

Entamoeba histolytica.

The most important parasitic amoeba of humans is Entamoeba histolytica. Entamoeba coli, a nonpathogenic amoeba, may also be found in humans and pigs? 

What are the ciliates? 

Ciliates are protozoans that are covered with tiny, short hairs over most of their body surface. These tiny hairs are called cilia, thus the name ciliates. Ciliates move with these beating, undulating hairs. As with amoebae, ciliates demonstrate two forms: the motile trophozoite form and the resistant cyst form. In their trophozoite, or moving, form, ciliates dart and twirl speedily in liquid media.

What are the different protozoa in the ciliates of dogs and cats?

Balantidium coli 

What are the apicomplexans? 

Of the protozoans, the apicomplexans are the most diverse and the most complicated. The apicomplexans are parasites of almost every animal phylum. In domesticated animals, they are found primarily in the epithelium of the intestine, within blood cells, and within cells of the reticuloendothelial system. The life cycles of these protozoans vary among the genera that affect domesticated animals; however, they do have a common trait in that their life cycles are complex and intimately integrated into the physiology of the host’s body. The locomotory organelles of the flagellates, amoebae, and ciliates (i.e., flagella, pseudopodia, and cilia, respectively) are discernible. In contrast, the locomotory organelles of the apicomplexans are not visible to the naked eye; their locomotory organelles are internal. The apicomplexans are often banana-, comma-, or boomerang shaped (Fig. 10.6) and move via undulations.

What are the different protozoans of veterinary importance in the Apicomplexans in dogs and cats?

- Cystoisospora

- Sarcocystis
- Toxoplasma 

- Plasmodium 
- Cryptosporidium 

- Babesia (blood)
- Cytauxzoon felis (blood)

- Eimeria

What is the cyst stage called for Apicomplexans?

Oocyte

What is the life cycle of Apicomplexans?

Dog, Cat, Pig → Oocyte passed in feces → Oocytes (infective stage) found in water and food in environment from contaminated feces → Oocyte ingested by new host → Oocyte develops into sporozoite → Sporozoites asexually reproduce and become Merozoites → Cell containing merozoites dies → Merozoites released from dead cell → Merozoites develop into microgametocytes and macrogametocytes, Sporocytes in Oocytes are produced and cycle continues..?

What are the common intestinal protozoa?

Giardia (Which is NOT a Apicomplexa!)
 Coccidia:
 Isospora – now Cystoisospora
 Cryptosporidium
 Sarcocystis
 Toxoplasma gondii
 Eimeria

Do ruminants have any ciliates? 

No, only non pathogenic ciliates.

Apicomplexans of ruminants?

Eimeria species, Eimeria bovis, and Eimeria zuernii, Cryptosporidium species (also in dogs and cats), Babesia bigemina (Blood). 

What are the flagellates of ruminants? 

Trypanosoma species, and Tritrichomonas foetus.

What are the flagellates of horses?

Giardia assemblage E

Do horses have ciliates? 

No pathogenic ciliates. 

What are the apicomplexans of horses.  

Eimeria leuckarti, Theileria (formerly Babesia) equi and Babesia caballi (blood), Klossiella equi (urogenital), Sarcocystis neurona.

How do we detect protozoa?

Blood smears for blood protozoa and cytology, direct smear and fecal flotation for intestinal protozoa.

What are the blood parasites? (all flagellates or amoebas?) 

Trypanosomes sp (humans, primates, dogs), Babesia bigemina (cattle), Babesia canis (dogs), B. bigemina (cattle), B. equi and B. caballi (horses, now Theileria), Leishmania (dogs, cats and humans).

What protozoan causes Chagas disease? 

Trypanosomes

Trypanosomes spp - What are they and where are they found? What species is important and who is it in? What is their shape? What is the cyst stage? Where else can it be found? HOW is it transmitted?

Hemoprotozoans – flagellate found in southern U.S. Extracellular and “swim” in the blood

Trypanosoma cruzi - a parasite of humans/primates and dogs
 3 to 10 times as long as RBCs
 Banana shaped
 Swimming stage – trypomastigote
 Cyst stage – amastigote
 Also found in cardiac muscle and other tissue
▪ Transmitted by the Kissing bug or assassin bug (Triatoma spp.)

Babesia bigemina - what is it and species is it in? Shape and transmission?

BLOOD parasite found in the blood cells. Transmitted from the tick Boophilus annulatus.
Tear shaped.

Babesia canis - what is it? Shape? Who is the IH? 

Intracellular parasite of RBCs of dogs
 Also called a piroplasm (pear-shaped body)
 Diagnosis – basophilic pear-shaped trophozoites in RBCs on a
stained blood smear
 Tick is the intermediate host

What are the horse Babesia spp? (old name and new..)

B. equi, B. caballi NOW CALLED Theileria

Leishmania - what is it? Transmission? 2 forms..?

Hemoprotozoans that infect several mammals – dogs, cats, and humans.
Transmitted by flies of the genera Phlebotomus and Lutzomyia

Causes hair loss? Alopecia?
- Two forms of disease are recognized
- Mucocutaneous form characterized by skin sores
- Leishmania braziliensis
-Visceral form affects several internal organs (spleen, liver, and bone marrow)
- Leishmania donovani and Leishmania infantum

What are Trichomonads? 

Long, slender organisms with a single flagellum attached to the dorsal surface that forms a sail-like structure that ripples as it moves through debris

Tritrichomonas foetus

reproductive tract of cattle
- Prepuce of bulls and vagina, cervix, and uterus of cows

- Causes infertility, spontaneous abortions, and pyometra
- Diagnosis of motile trophozoite in the supernatant of washings from
vagina or prepuce

Trichomonas gallinae - Where is it found and how is it transmitted? Effects? How do we diagnose?

 Found in crop washings of pigeons, doves, and poultry
 Transmitted through drinking water
 Ulcerations of esophagus, crop, and proventriculus
 Diagnosis – direct saline smear of crop contents
 Air dried and stained with Wright stain

What is the flagellate of birds?

Histomonas meleagridis.

Histomonas meleagridis - who does it affect? Transmission? What is the common name? 

Infects turkeys, chickens, pheasants, and other avians
 Transmitted when the bird ingests the ova of the nematode –
cecal worm Heterakis gallinarum the intermediate transport host
 In turkeys, chickens, pheasants, and peafowl – fatal liver disease
 A.k.a. – infectious enterohepatitis
 Common Name – blackhead

What is Entamoeba histolytica? - who does it affect mainly and sometimes? Effects?

Entamoeba histolytica
 Primarily human parasite in tropical regions – amebic
dysentery.
 Also found in fecal flotations of: Healthy cattle, Sheep, Goats, Horses, Swine
 Generally no clinical significance
 May cause acute or chronic diarrhea in dogs

Cystoisospora spp? - What is it? Effects?

(Apicomplexan) Common Coccidia found in dogs and cats. Protozoal parasite of small intestine of dogs and cat. Can cause Coccidiosis - One of the most commonly diagnosed diseases in puppies and kittens (Rarely a problem in adult animals). Very small oocysts are found in stool sample. Can cause diarrhea, especially in puppies and kittens. Often is not treated in adult animals, as they serve little harm to the host.

Cryptosporidium sp? - what is it? Zoonosis? Who is it found in? Transmission?  Effect?

(Apicomplexan). Zoonotic protozoa.
 Found in the hosts of birds, reptiles, mammals, and fish.
 Oocysts are shed in feces, and other hosts can become
infected by ingestion of the feces.
 Can produce severe diarrhea if not treated. 

Sarcocystis - What is it? Who does it affect? Diagnosis? What is a disease one species of Sarcocystis causes in horses? Transmission?

(Apicomplexan) Coccidian of the small intestine
 Several species infect dogs and cats
 Diagnosis by fresh fecal flotation
 Sarcocystis neurona is the organism that causes EPM of horses,
food/water contaminated by the feces of opossum feces

(Smallest protozoan..??)

The asexual stage is found in omnivores and herbivores.
 The sarcocysts are then ingested by a carnivore, in which they were lying in the muscles, and then the sexual stage begins.
 When this occurs, a small, spindle-shaped organism penetrates cells of the intestine and immediately begins the sexual phase, which is completed in 11 to 14 days after the ingestion of the infected flesh.

What is Toxoplasma gondii? What is unique about their shedding? What does it cause? Who needs to be careful with this protozoa? How can we get it? Zoonosis? Who is the DH?

(Apicomplexan) Intestinal coccidian of cats. 

Only shed oocysts for less than 2 weeks for their entire life
Zoonotic protozoa- Is the cause of toxoplasmosis.
 Not harmful to healthy humans but can cause trouble with pregnant women through litter boxes
 Some humans can get from undercooked meat.

 Toxoplasmosis is caused by eating of either oocysts from cat feces or undercooked meat containing the cysts.

 This is a protozoan specific to cats. They become infected by
eating mice who are infected with the parasite. (as well as uncooked meat, which is another source of T. gondii).

Eimeria (leuckarti?) - what is it? - who is it in? what is the shape and color? 

(Apicomplexan) Coccidia often found in horses or cattle.(Leuckarti is in horses small intestine) (Ruminants and rabbits may host many species of Eimeria: High mortality in young rabbits)
 If an oocyst is seen on a fecal flotation of a dog or cat, it is
most likely there by accident. (A spurious infection.)
animals that might eat horse or cow manure will sometimes
pass this oocyst in their stool, but is not usually treated, as it
is transient parasite oocyst. (Noted as coccidia)
 This coccidia is often tear-drop shape and brownish in color.

What is another name for Giardia? What category is it in?

Beaver fever. (Apicomplexan)

What are the 2 forms of Giardia? Who is effected by Giardia? 

Motile form- trophozoite - Pear shaped, dorsoventrally flattened with four pairs of flagella, two nuclei resemble a pair of eyes
Resistant/infective form- cyst

Infection can occur in dogs, cats, humans and beavers most commonly

Life cycle of Giardia?

Cyst is passed in feces → Cyst gets into water or are picked up in contaminated ground → Cysts are ingested by new or same host → Parasite excysts into trophozoite form in intestines → They multiply and feed in intestines.
^^When the cyst form is ingested- the cyst wall begins to digest away, and the trohozoite emerges, which then divides into 2 organisms. Here, they continue to multiply over the next 6 to 10 days until a large population exits.

Diagnosis is made by examining fecal matter by direct smear, most often. Giardia is most common in young dogs and cats that are housed together in shelters. Seen on 10x or 40 x.

List some zoonotic Protozoan?

 Hymenolepis nana (Rodent Tapeworm)

 Hymenolepis diminuta (Rodent Tapeworm)

 Taenia solium/Cysticercus cellulosae (Pork Tapeworm)

 Taneia hydatigena/Cysticercus tenuicollis (Bladderworms) or larval stages

 Taenia saginata/Cysticercus bovis (Beef Tapeworm)

 Dipylidium caninum

 Echinococcus granulosus

 Echinococcus multilocularis

 Spirometra spp. (psudeotapeworm; Zipper tapeworm)

 Diphyllobothrium spp. (psudeotapeworm; Broad fish tapeworm

Cytauxzoon felis - what is it? - where are they found? What do they look like? What do they cause?

(Apicomplexan) BOBCAT FEVER! Blood coccidia!! LOOKS LIKE HJ bodies!

Intracellular parasite of RBCs of cats
 Found throughout the U.S.
 Piroplasms – bejeweled ring
 Rapidly fatal disease – fever, icterus, anemia, dehydration and
death

Hepatozoon canis and Hepatozoon americanum - what are they? where are they found? Transmission? 

(Apicomplexan) Intracellular, malaria-like parasites affecting dogs
 Blood forms – found in leukocytes
 Also found in muscle tissues
 Ingestion of infected tick

What protozoa is the cause for Malaria?

The genus Plasmodium

Plasmodium - what is it? What does it cause? Transmission? Diagnosis?

(Apicomplexan)
 Malaria in mammals, birds, and reptiles
 Transmitted by mosquitos
 Diagnosis – blood smear, organ impression smear, or
histopathologic examination of the liver and spleen

What is the 1 genus of ciliate of veterinarian importance? 

Balantidium coli

Balantidium coli - what is it? Effects in dogs? 2 stages?

Ciliate – large intestine of swine. Ciliated protozoan usually associated with pigs
 When in dog cecum/colon usually associated with diarrhea
 Two stages: Cyst and motile trophozoite stage

What are Rickettsial Parasites? What are the 4? and transmission?

A group of obligate intracellular (blood parasites) gram-negative bacteria
 Anaplasma, Ehrlichia,Wolbachia, and Neorickettsia
 Transmitted by arthropod or helminth vectors

What is Leucocytozoan/who does it effect, where?

Infects WBCs of raptors as well as psitticine birds

Which protozoan causes abortions in cattle?

Tritrichomonas foetusT (Sarcomastigophora-Flagellates): Causes reproductive effects/spontaneous abortion in CATTLE

Neosporosis (Apicomplexa): Causes abortion in CATTLE

Which protozoan causes abortions in people?

 Toxoplasma gondii (Apicomplexa): Causes harm/abortion of HUMAN FETUS

What causes RMSF?

Rocky Mounatin Spotted Fever

Rickettsia rickettsii Bacteria: Transmitted by American Dog Tick, Causes RMSF

What causes Lyme’s disease?

Bacteria: Transmitted by Deer/Black-Legged Tick, Causes Lyme Disease

What causes Tularemia?

Francisella tularensis Bacteria: Transmitted by many ticks, Causes Tularemia

What category of most blood borne pathogens.

Sarcomastigophora--Flagellates

 Trypanosoma cruzi

 Leishmania

Apicomplexa

 Babesia bigemina

 Babesia canis

 Cytauxzoon Cytauxzoon felis

— Hepatozoon Hepatozoon canis and Hepatozoon americanum

 Plamodium spp.

 Leucocytozoan

What or who can transmit blood borne protozoans? How would you recognize them (like Babesia)?

Insect VECTORS can transmit blood borne protozoans: Ticks, Mosquitos, Kissing Bug (Chagas Dz)

 Babesia spp.

o Intracellular parasite—Found within RBC; Pear/tear-shaped, basophillic organism

 Trypanosoma cruzi

o Extracellular parasite; Banana-Shaped; Lateral, undulating membrane with whip-like tail/flagellum

 Leishmania

o Sent to pathologist (histopathologic sectioning of infected organs)

 Cytauxzoon

o Intracellular parasite—Found within RBC; Produces piroplasm—bodies described as

being shape of “bejeweled ring”/Ring-form

— Hepatozoon

— Intracellular parasite—Found within WBC; WBC containing gamots (adult form) stain

pale blue to dark red. Numerous pink granules are found in cytoplasm of WBC

 Plamodium spp.

o Intracellular parasite—Found in RBC; A “signet ring” form occurs when the body of the

organism displaces the RBC nucleus

 Leucocytozoan

o Intracellular parasite—Found in WBC; Size of organism greatly distorts the shape and

appearance of the WBC

Where or what are Trophozoites and Cysts (bradyzoites)

Trophozoite (Stage of feeding, movement, and reproduction): NON-INFECTIVE (The trophozoite is often too fragile to survive transfer to a new host) FOUND in HOST’s body fluids, tissues, and stool

Transmission to host occurs in the cyst stage: Metabolic functions suspended, prevents desiccation, cyst

stage occurs under certain conditions FOUND in external environment

Bradyzoites: Cysts from the parasite Toxoplasma gondii that forms tissue cysts primarily in the

brain/muscle

Giardia are found where (in the body & environment)? How is it diagnosed?

Found in intestinal mucosa of host

Giardia CYSTS are found in soil, food, and water contaminated with FECES

Diagnosis: Standard fecal floatation, direct fecal smear, fecal immunodiagnostic tests are MOST

COMMON

How is Toxoplasmosis prevented?

 Avoid consuming undercooked or raw meat, unpasteurized milk, untreated water

 Wash fruits/veggies well

 Wear gloves when gardening or cleaning cat litterbox

 Clean cat litterbox daily (PER CDCToxoplasma parasite does not become infectious until 1 – 5 days

after a cat shed it in its feces)

 Wash fruits/veggies well

 WASH HANDS

A large ciliate that may be found in swine feces is:

 A. Balantidium
 B. Tritrichomonas
 C. Giardia
 D. Histomonas

A. Balantidium

Cysts of what organism may be seen on a fecal flotation?

 A. Giaradia
 B. Mycoplasma (Haemobartonella)
 C. Toxoplasmosis
 D. Tritrichomonas

A. Giardia

Which parasite is diagnosed by examining blood?
 A. Dioctophyma renale
 B. Dictyocaulus spp.
 C. Anaplasma spp.
 D. Trithrichomonas spp.

C. Anaplasma spp.

To examine for trophozoites, it is best to use a mixture of
fresh feces and _____.
 A. Sodium chloride (concentrated solution)
 B. Sodium nitrate
 C. Zinc sulfate
 D. Physiologic saline

D. Physiologic Saline.