Blood Protozoa I

What are the two examples of Apicomplexa › piroplasms: tick-borne parasites of red cells

• Babesia

• Theileria and Cytauxzoon

The parasite is Babesia what is the host, stages in the host, and what disease do they cause

• host: dogs, cattle, horses

• stages in host: Red-cell stages only

• causes of disease: red cell destruction and the inflammatory response

The parasite is Cytauxzoon felis what is the host, stages in the host, and what disease do they cause

• host: cat

• stages in the host: Schizonts in macrophages, then piroplasms in red cells

• causes of disease: Tissue schizonts that block small vessels

The parasite is Theileria parva what is the host, stages in the host, and what disease do they cause

• host: cattle/Africa

• stages in the host: Infected white cells multipl (transforming); then red cells

• disease causes: White-cell proliferation: lymph nodes, lungs, whole body

The parasite is T. orientalis Ikeda what is the host, stages in the host, and what disease do they cause

• host: cattle

• stages in the host: Brief white-cell phase; mainly red cells (non- transforming)

• causes of disease: Anemia from red-cell injury

Not every parasite seen in a red cell causes what

disease by destroying red cells.

Canine babesiosis causes what ?

a tick-borne piroplasm of red cells that causes hemolytic anemia.

In canine babesia what re the Two groups by size on a blood smear:

• smear: large and small

• Size predicts how it spreads, how sick the dog gets and which drug works.

What are the three large species of Canine Babesia

species, B. vogeli, B. canis and B. rossi,

In the U.S. which tick do we care the most

In the US, B. vogeli and B. gibsoni matter most

What does Large Babesia look like in the smear

Large Babesia describe the shape, size, species (where), how spread, dogs at risk, clinical picture, drug of choice, and after treatment

• size/shape: Paired pears, 2.5 × 5 μm

• species: B. vogeli: worldwide, US; B. canis: Europe; B. rossi: Africa; Babesia sp. 'coco': US, uncommon

• how spread: Tick bite: brown dog tick

• Dogs at risk: Puppies; kennel dogs; greyhounds

• Clinical picture:Often milder; severe in puppies

• Drug of choice: Imidocarb

• After treatment: Clinical cure; carrier for life

Small Babesia describe the shape, size, species (where), how spread, dogs at risk, clinical picture, drug of choice, and after treatment

• size/shape: Single rings, 1 × 3 μm

• species: B. gibsoni: worldwide, US; B. conradae: California; B. vulpes: uncommon

• how spread:Bites and blood: fights, transfusion, dam to pup

• Dogs at risk: Pit bull-type, fighting dogs; coyote-hunting greyhounds

• Clinical picture:Often more severe; chronic, relapsing

• Drug of choice: Atovaquone + azithromycin

• After treatment: Relapse and resistance; recheck PCR

What does Small Babesia look on the smear

What is the definitive host for Canine Babesia

Definitive host (vector) Tick: brown dog tick (B. vogeli)

What is the intermediate host for Canine Babesia

Intermediate host Dog; also wild canids

What is the first stage of the lifecycle of babesia vogeli

• tick injects sporozoites

What is the second stage of the lifecycle of babesia vogeli

• sporozoites invade red cells

What is the third stage of the lifecycle of babesia vogeli

• red cells: multiply and reinvade hemolytic anemia

What is the fourth stage of the lifecycle of babesia vogeli

• tick ingest infected red cells

• Molt: transstadial

• transovarial: infected eggs and larvae

Only the red-cell stage lives in the

dog

We fever, lethargy: pale or icteric gums; a big spleen; what do we see in the blood work and who gets sick

• bloodwork: anemia (regeneration may lag); low platelets

• whoe gets sick: Puppies; dogs with B. gibsoni

We see Red-brown urine: hemoglobinuria (intravascular), what do we see in the bloodwork and who gets sick

• high globulins and low albumin

• no spleen, or on corticosteriods; replaces

What are the strengths for a blood smear to diagnosis Canine babesiosis

Fast; size says large or small

What are the limitation for a blood smear to diagnosis Canine babesiosis

Parasites are often scarce, especially in carriers

What are the limitation for a PCR to diagnosis Canine babesiosis

Can miss very low numbers; sample before treatment

What are the strength for a PCR to diagnosis Canine babesiosis

Sensitive; the way to identify the species

What are the strength for a Serology to diagnosis Canine babesiosis

Shows exposure

What are the Limitation for a Serology to diagnosis Canine babesiosis

Cross-reacts; early infection may be negative

negative smear does not rule out what

Babesia. Send blood for PCR.

The parasite is Large: B. vogeli what is the drug we suse and what do we expect the outcome

• drug: Imidocarb, two injections 14 days apart

• What to expect: Clinical cure; treat as a carrier for life

The parasite is Small: B. gibsoniwhat is the drug we suse and what do we expect the outcome

• drug: Atovaquone and azithromycin, 10 days

• what to expect: Relapse and drug resistance occur; recheck

  PCR

If we have a severe case of Canine babesiosis what drug do we use and what do we expect

• drug: Supportive care; transfusion for severe anemia

• what to expect: Avoid unnecessary immunosuppression

What is the control we can do to prevent Canine babesiosis

• Year-round tick control: the brown dog tick lives and breeds indoors, in kennels and houses.

• Screen blood donors by smear, PCR and serology.

• Discourage dog fighting; test the other dogs from the same fights or kennel.

• No vaccine in North America.

Babesia microti: a parasite of what animal

white-footed mouse.

How is Zoonotic Babesia spread by what ?

• Spread by the blacklegged tick, the Lyme disease tick: mostly the tiny nymph, in spring and summer.

Where do you nomrally see Zoonotic Babesia, what region

US Northeast and upper Midwest.

In Europe, which parasiste is in cattle

B. divergens

Which mammal is considered a dead zone in Zoonotic Babesia

People are dead-end hosts, but it passes in blood transfusions: donated blood is tested in high-risk states.

How do you treat Babesia microti

Treated with atovaquone and azithromycin, as for B. gibsoni.

Canine Babesia are not recognized human pathogens: the dog is not the

source

Babesia microti: What are the clinical signs

Fever and hemolytic anemia; severe with no spleen, in old age or immunosuppression.

Cytauxzoon felis: a tick-borne piroplasm of what animal

cats: macrophages first, then red cells.

What is the disease of Cytauxzoon felis:

cytauxzoonosis, an acute, often fatal fever and icterus.

Where will we normally see in Cytauxzoon felis and also what season do we normally see it

• Where: southeast and south-central US

• March to September; cases now occur farther north.

We mentioned that cats commonly get Cytauxzoon felis but what is the risk on how they get Cytauxzoon felis

At risk: outdoor cats in tick season.

What is the definitive host for Cytauxzoon felis

• Lone star tick; the American dog tick

Who is the intermedite host for Cytauxzoon felis

• cat

Who is the reservoir for Cytauxzoon felis

• Bobcats; survivor cats are lifelong carriers

Which two stages of Cytauxzoon felis are the diagnostic stages

schizonts kill, piroplasms are diagnostic stage

What do we mean by Transstadial and how does it occur

transovarial passage unclear: each tick must feed on an infected cat or bobcat.

What is the first step of Cytauxzoon felis — life cycle

• lone star tick injects sporozoites while feeding

What is the second step of Cytauxzoon felis — life cycle

• schizonts in marcophages block small vessels

What is the third step of Cytauxzoon felis — life cycle

• merozites infect red cells: piroplasms

What is the fourth step of Cytauxzoon felis — life cycle

• another tick ingest infected red cells of a carrier cat or bobcat

What is the fifth step of Cytauxzoon felis — life cycle

• sexual stage in tick: sporozoites in salivary glands after the molt

Schizont-laden macrophages obstruct what

small vessels in the lungs, liver, spleen and lymph nodes.

Schizont-laden macrophages obstruct smallvvessels in certain systems what is the result of it

§ The result: poor circulation, organ failure and clotting problems (DIC).

Red cell destruction adds what

hemolytic anemia and icterus.

What are the poor prognosis if Cytauxzoonosis is not resolved

§ Cats with low temperature or breathing difficulty have a very poor prognosis.

What are the preventions for Cytauxzoonosis

• keep cats indoors; otherwise year-round, cat-labeled tick control.

• No vaccine.

What is the treatment for Cytauxzoonosis

• atovaquone and azithromycin for 10 days with intensive care; 60% survived in one clinical trial

What is the diagnosis for Cytauxzoonosis

• the tissue stage comes first, so a very sick cat can have a negative smear early.

• Look for small 'signet-ring' piroplasms in RBC

• Schizonts in spleen, node or marrow aspirates

• PCR (also positive in carriers).

Babesia bigemina (large) and B. bovis (small): is found in what animal

piroplasms of cattle

How does Bovine babesiosis spread

Spread by cattle fever ticks, Rhipicephalus (Boophilus): one-host ticks.

If a cow got Texas cattle fever (redwater): what do we see in blood work and upon exam

hemolytic anemia, red urine.

B. bovis also causes what

cerebral babesiosis

Eradicated from the mainland US in 1943; still in active in what countries

Mexico and the tropics.

Who were the two scientist that mentioned that arthropods can transmit disease

Smith and Kilborne

T. orientalis Ikeda is the parasite where is it located, what kind of tick, what kind of disease, what is the diagnosis, and what is the status in the US

• where: USA: Virginia 2017; now East and Midwest (New Jersey 2024)

• tick: Asian longhorned tick

• disease: Non-transforming: red-cell injury, anemia, abortion, death

• diagnosis: Smear; PCR names the genotype

• US status: Established and spreading; notifiable: follow state rules

T. parva is the parasite where is it located, what kind of tick, what kind of disease, what is the diagnosis, and what is the status in the US

• where: Africa (East Coast fever)

• tick: Brown ear tick

• disease: Transforming: white cells multiply; big nodes, lung edema

• diagnosis: Schizonts in lymph node aspirates; PCR

• US status: Foreign animal disease: report at once

Theileria equi is the parasite its in horses what do the cells look like infectedly

White cells, then red cells: Maltese cross

Theileria equi is the parasite its in horses whats the Course of the stage of this parasite

More severe; usually a lifelong carrier

Babesia caballi is the parasite its in horses what do the cells look like infectedly

Red cells only; large, paired

Babesia caballi is the parasite its in horses what is the course of the parasite

Milder; persists months to years; may clear

What is the sign/symptoms for Equine piroplasmosis

• Fever, anemia, icterus, weight loss; carriers look healthy.

How does Equine piroplasmosis spread

• US spread: contaminated needles; illegally imported horses.