Genera Ehrlichia, Neorickettsia, Anaplasma, Wolbachia

Question 1

Organisms in the Genus Ehrlichia infect _____ while some also infect ____

Answer 1

circulating leukocytes

Vascular endothelial cells

Question 2

_______ is the cause of heartwater disease in ruminants

Answer 2

Ehrlichia ruminantium

Question 3

Ehrlichia ruminantium prefers to infect what? Would it be possible for this to spread to the US?

Answer 3

Prefers to infect vascular endothelial cells

YES; we have the ticks that readily carry it

Question 4

What are two organisms that cause benign bovine and ovine ehrlichiosis in Africa?

Answer 4

Ehrlichia bovis and Ehrlichia ovis

Question 5

_____ is the cause of canine ehrlichiosis. Where is it found? Where did the latest epidemic occur?

Answer 5

Ehrlichica canis
Tropical and Sub-tropical areas
Vietnam, involved military dogs

Question 6

What does Ehrlichia canis affect?

Answer 6

Circulating leukocytes

Question 7

What is the primary resevoir for Ehrlichia canis? How long can it survive?

Answer 7

Brown dog tick

A long time, can survive over the winter

Question 8

What are the three stages of canine ehrlichiosis

Answer 8

Acute phase: 2-4 weeks, multiplies in mononuclear cells and spreads throughout the body. Thrombocytopenia is a common finding.
Subclinical phase: 40-120 days after acute phase. In immunocompetent dogs this is the last stage.
Chronic phase: results in terminal pancytopenia

Question 9

What animals are most likely to be infected with the chronic form of canine ehrlichiosis?

Answer 9

German shepherds

Question 10

T/F As long as the animal harbors the organism, it is immune to reinfection

Answer 10

TRUE

Question 11

_______ is the cause of Potomac horse fever or equine monocytic ehrlichiosis

Answer 11

Neorickettsia risticii

Question 12

T/F Neorickettsia risticii is not present in IOWA

Answer 12

FALSE; has been isolated from at least 32 states, including Iowa

Question 13

When is infection with Neorickettsia risticii most likely to occur? Where does it grow that no other ricketsial organisms do?

Answer 13

Summer months

Grow in the intestinal epithelium of mammals, along with macrophages, mast cells, and circulating monocytes

Question 14

What clinical signs are seen with Neorickettsia risticii infections? What are the three forms?

Answer 14

Gastrointestinal disease is the major manifestation of the illness
Acute: sudeen onset of fever, colitis, laminitis, and depression with diarrhea 1-3 days after clinical signs
Subacture: No diarrhea
Mild or inapparent form: determined by serological studies

Question 15

How would you treat an animal infected with Neorickettsia risticii?

Answer 15

IV fluids and oxytetracycline

Question 16

_______ causes salmon poisoning disease in canines

Answer 16

Neorickettsia helminthoeca

Question 17

Where is Neorickettsia helminthoeca seen? What limits it to this area?

Answer 17

NW California to SW Washingtong

The snail that harbors the disease and is necessary for infection resides in this place only

Question 18

What is the vector for Neorickettsia helminthoeca?

Answer 18

Nanophyetus salmncola. PARASITES EVERYWHERE

Question 19

What are some definitive hosts for Neorickettsia helminthoeca? Which ones experience clinical signs?

Answer 19

Raccoons, dogs, and bears

Clinical signs usually only seen in dogs

Question 20

How does a dog become infected with Neorickettsia helminthoeca?

Answer 20

By ingesting raw fish

Question 21

Is infection with Neorickettsia helminthoeca a serious disease?

Answer 21

YES; if not treated the dog will likely die in 7-10 days

Question 22

_______ was previously known as the Elokomin fluke fever agent and causes a disease similar to salmon poisoning

Answer 22

Neorickettsia elokominica

Question 23

The genus Anaplasma is made up of _____ parasites that reside where?

Answer 23

Obligate

Within erythrocytes or free in the plasma in ruminants

Question 24

How is Anaplasma transmitted?

Answer 24

Any route where blood is transmitted, including arthropods, needles, and surgical instruments

Question 25

What is the most prominent clinical sign associated with Anaplasma?

Answer 25

Acute anemia

Question 26

_________ is the anaplasma species that is most pathogenic for cattle

Answer 26

Anaplasma marginale

Question 27

What age of cattle does Anaplasma marginale affect?

Answer 27

Young adult to older cattle

Cattle

Question 28

T/F Severity of Anaplasma marginale decreases as the animal gets older

Answer 28

FALSE; severity and mortality increases as the animal gets older

Question 29

T/F Blood recovered from an animal infected with Anaplasma marginalis is infectious for many years, probably life

Answer 29

TRUE

Question 30

What are the two biological carriers of Anaplasma marginalis?

Answer 30

Pacific coast tick and Rocky Mountain wood tick

Question 31

What are the four stages that exist with Anaplasma marginale?

Answer 31

Incubation stage: 3-8 weeks
Developmental stage: anemia develops
Convalescent stage: appearance of the reticulocytes return to normal
Carrier stage: Clinically recovered animals remain carriers with non-detectable parasitemia for life

Question 32

What is the best way to control Anaplasma marginale?

Answer 32

Remove the carriers

Question 33

________ produces a centrally located inclusion in erythrocyte and causes a milder disease than Anaplasma marginale

Answer 33

Anaplasma centrale

Question 34

_______ causes disease in sheep and goats but not cattle

Answer 34

Anaplasma ovis

Question 35

_______ is most often involved in subclinical disease or a chronic carrier state but can be confused with Lyme disease

Answer 35

Anaplasma phagocytophilum

Question 36

What transmits Anaplasma phagocytophilum? What are the resevoir hosts?

Answer 36

Ixodid ticks

Whitetailed deer and several species of rodents

Question 37

What do you see Wolbachia with?

Answer 37

Heartworm disease