Genera Ehrlichia, Neorickettsia, Anaplasma, Wolbachia Flashcards
Organisms in the Genus Ehrlichia infect _____ while some also infect ____
circulating leukocytes
Vascular endothelial cells
_______ is the cause of heartwater disease in ruminants
Ehrlichia ruminantium
Ehrlichia ruminantium prefers to infect what? Would it be possible for this to spread to the US?
Prefers to infect vascular endothelial cells
YES; we have the ticks that readily carry it
What are two organisms that cause benign bovine and ovine ehrlichiosis in Africa?
Ehrlichia bovis and Ehrlichia ovis
_____ is the cause of canine ehrlichiosis. Where is it found? Where did the latest epidemic occur?
Ehrlichica canis
Tropical and Sub-tropical areas
Vietnam, involved military dogs
What does Ehrlichia canis affect?
Circulating leukocytes
What is the primary resevoir for Ehrlichia canis? How long can it survive?
Brown dog tick
A long time, can survive over the winter
What are the three stages of canine ehrlichiosis
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
What animals are most likely to be infected with the chronic form of canine ehrlichiosis?
German shepherds
T/F As long as the animal harbors the organism, it is immune to reinfection
TRUE
_______ is the cause of Potomac horse fever or equine monocytic ehrlichiosis
Neorickettsia risticii
T/F Neorickettsia risticii is not present in IOWA
FALSE; has been isolated from at least 32 states, including Iowa
When is infection with Neorickettsia risticii most likely to occur? Where does it grow that no other ricketsial organisms do?
Summer months
Grow in the intestinal epithelium of mammals, along with macrophages, mast cells, and circulating monocytes
What clinical signs are seen with Neorickettsia risticii infections? What are the three forms?
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
How would you treat an animal infected with Neorickettsia risticii?
IV fluids and oxytetracycline
_______ causes salmon poisoning disease in canines
Neorickettsia helminthoeca
Where is Neorickettsia helminthoeca seen? What limits it to this area?
NW California to SW Washingtong
The snail that harbors the disease and is necessary for infection resides in this place only
What is the vector for Neorickettsia helminthoeca?
Nanophyetus salmncola. PARASITES EVERYWHERE
What are some definitive hosts for Neorickettsia helminthoeca? Which ones experience clinical signs?
Raccoons, dogs, and bears
Clinical signs usually only seen in dogs
How does a dog become infected with Neorickettsia helminthoeca?
By ingesting raw fish
Is infection with Neorickettsia helminthoeca a serious disease?
YES; if not treated the dog will likely die in 7-10 days
_______ was previously known as the Elokomin fluke fever agent and causes a disease similar to salmon poisoning
Neorickettsia elokominica
The genus Anaplasma is made up of _____ parasites that reside where?
Obligate
Within erythrocytes or free in the plasma in ruminants
How is Anaplasma transmitted?
Any route where blood is transmitted, including arthropods, needles, and surgical instruments
What is the most prominent clinical sign associated with Anaplasma?
Acute anemia
_________ is the anaplasma species that is most pathogenic for cattle
Anaplasma marginale
What age of cattle does Anaplasma marginale affect?
Young adult to older cattle
Cattle
T/F Severity of Anaplasma marginale decreases as the animal gets older
FALSE; severity and mortality increases as the animal gets older
T/F Blood recovered from an animal infected with Anaplasma marginalis is infectious for many years, probably life
TRUE
What are the two biological carriers of Anaplasma marginalis?
Pacific coast tick and Rocky Mountain wood tick
What are the four stages that exist with Anaplasma marginale?
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
What is the best way to control Anaplasma marginale?
Remove the carriers
________ produces a centrally located inclusion in erythrocyte and causes a milder disease than Anaplasma marginale
Anaplasma centrale
_______ causes disease in sheep and goats but not cattle
Anaplasma ovis
_______ is most often involved in subclinical disease or a chronic carrier state but can be confused with Lyme disease
Anaplasma phagocytophilum
What transmits Anaplasma phagocytophilum? What are the resevoir hosts?
Ixodid ticks
Whitetailed deer and several species of rodents
What do you see Wolbachia with?
Heartworm disease
