Ectoparasites I: Tick-Borne Protozoa Flashcards
What are the canine Hepatozoon spp?
Hepatozoon americanum
Hepatozoon canis
What is Hepatozoon americanum the causative agent?
American canine hepatozoonosis
Where is Hepatozoon americanum found?
North America (southern US) South and Central America
What is the definitive host for Heptaozoon americanum?
Tick vector: Amblyomma maculatum (Gulf Coast Tick)
What is the intermediate host for Hepatozoon americanum?
Canids
What is the paratenic host for Hepatozoon americanum?
Rodents, rabbits
What is the PPP for Hepatozoon americanum?
32 days
How does the dog get infected with Hepatozoon americanum?
It ingests the tick
Describe the indirect life cycle of Hepatozoon americanum
Mature oocysts in tick hemocoel
Dog ingests tick with oocysts
Sporozoites penetrate intestine, circulate, and enter tissue
Merozoites released from mature meronts
Gamonts form
Tick ingests leukocytes containing gamonts
Describe the cycle of Hepatozoon american for the paratenic host
PH ingests tick
Cystozoites in PH tissues
Dog ingests ticks on PH or PH with cystozoites
What are the Hepatozoon americanum infective stages in the tick vector (DH)?
Ingests canine leukocytes with gamont
What are the Hepatozoon americanum infective stages in the dog (IH)?
Ingests tick with oocysts or PH with Cystozoites
What is the site of infection for Hepatozoon americanum in the tick vector (DH)?
Mature oocysts in hemocoel
What is the site of infection for Hepatozoon americanum in the dog (IH)?
Gamonts in leukocytes
Meronts in skeletal and cardiac muscle
What is the site of infection for Hepatozoon americanum in the PH?
Cystozoites in skeletal and cardiac muscle, kidney, lung
What is the pathology of American Canine Hepatozoonosis (ACH)?
Neutrophilic leukocytosis (moderate anemia) Periosteal bone proliferation (primarily long bones, primarily younger dogs) Tissue lesions (onion skin cyst*, pyogranulomas)
What are the presumptive diganosis methods of ACH?
Profound neutrophilia
Periosteal bone lesions (extension/thickening of long bones)
Clinical signs, history
What are the definitive diagnosis methods of ACH?
Gamonts in leukocytes
Muscle biopsy*
PCR
ELISA
What is collected to find ACH gamonts?
Buffy coat in blood
Where are onion skin cysts usually found?
In cardiac, skeletal muscle
Describe pyogranulomas
Rupture of cyst with mature meront— merozoites released, inflammatory cell infiltration
What is the treatment for ACH?
No treatment effective
Can be treated in acute cases
What is the control method for ACH?
Reduce risk of exposure
Describe Hepatozoon canis
Usually subclinical
–presentation different in US vs elsewhere
What is the definitive host of Hepatozoon canis?
Tick vector Rhipicephalus sanguineus (brown dog tick)
What is the intermediate host of Hepatozoon canis?
Canids
What is the PH pf Hepatozoon canis?
Rodents
What makes Hepatozoon canis different from H. americanum?
Higher number of WBCs infected
Meronts are in lymph nodes, bone marrow, spleen
Meront look like “wheel spoke” meronts
Dogs usually asymptomatic unless immunocompromised
Good prognosis with treatment
PH has monozoic cyst
Where is Cytauxzoon felis found?
North America: southeaster, South-Central, Mid-Atlantic states
What is the DH for Cytauxzoon felis?
Tick vector (amblyomma americanum: Lone star tick)
What is the IH for Cytauxzoon felis??
Felids (Bobcat are reservoirs)
Describe the indirect life cycle of Cytauxzoon felis
Tick bites cat Sporozoites injected Sporozoites invade endothelial-associated mononuclear phagocytes, replicate, develop into "schizonts" Merozoites released from schizonts Merozoites enter RBCs (piroplasma) Nymphal tick feed on infected cat; ingests merozoites Merozoites mature to gamtes Sporozoites move to tick salivary gland
What is the PPP of Cytauxzoon felis?
1-3 weeks
What are the infective stages of Cytauxzoon felis in the DH?
Merozoites from infected RBCs
What are the infective stages of Cytauxzoon felis in the IH?
Sporozoite from infected tick or from blood transfusion
What are the sites of infection for Cytauxzoon felis in the IH?
Merozoites in RBCs
Schizonts in macrophages associated with endothelium of lung, liver, lymph node, spleen, bone marrow
What is the pathology of Cytauxzoonosis?
Leukopenia; thrombocytopenia; non-regenerative anemia; elevated liver enzymes
Progressive illness (multiple organ failure)
2 phases:
1. Leukocytic (schizont; primary cause of clinical disease)
2. Erythrocytic (merozoites; RBC hemolysis)
What are the methods of diagnosing cytauxzoonosis?
Clinical signs, history
Merozoites in stained blood smears
Schizonts in macrophages (bone marrow, lymph node, spleen aspirates; impression smears, biopsy material)
What is the treatment for cytauxzoonosis?
No efficacious treatment; poor prognosis
What are methods of control for cytauzoonosis?
Reduce tick exposure
Routine on-animal tick control
Remove tick immediately
Where is Babesia spp. found?
Worldwide
What is the DH for Babesia?
Tick vector (wide range)
WHat is the IH for Babesia?
Various wild and domestic animals (canids*); humans
Piroplasms in RBCs
Describe the general Babesia life cycle
Infected tick transmits sporozoites to vertebrate host via tick saliva
Sporozoites invade RBCs— develop and asexually replicate— merozoites
Ticks get infected by biting infected vertebrate- ingests RBCs
What are the 3 main causes of canine babesiosis?
Babesisa canis vogeli
B. gibsoni
B. conrade
Describe B. canis vogeli
Enzootic in US, especially South (Greyhound kennels)
DH: tick vector (Rhipicephalus sanguineus- brown dog tick)
Describe B. gibsoni
In US, American Stafforshire and Pit Bulls
DH: tick vector
Describe B. conradae
No breed predilection; California
DH: tick vector is unknown
What is the transmission of canine babesiosis to canids in US?
Bite from infected tick vector
Direct animal to animal (dog fights, Iatrogenic, transfusions, transplacental)
What is the transmission of canine babesiosis to DH?
Blood meal from dog
Transovarial transmission
What is the pathology for canine babesiosis?
Hemolytic anemia
Thrombocytopenia
Hemoglobinuria
Hemoglobinemia
What are clinical signs for canine babesiosis?
Splenomegaly
What are the diagnostic methods for canine babesiosis?
Blood smears
Antibody testing
PCR
What is the treatment for canien babesiosis?
Reduce parsitemia
What is the control for canine babesiosis?
Decrease tick exposure
Routine on-animal tick control
Remove ticks
What are the causes of bovine babesiosis?
B. bovis
B. bigemina
What is the DH of bovine babesiosis?
Tick vectors (rhipicephalis microplus and annulatus; erradicated from US)
What is the IH of bovine babesiosis?
Cattle, other ruminants
What are causes of Equine Piroplasmosis?
B. caballi
Theileria equi
What is the DH of Equine Piroplasmosis?
Tick vector (Dermacentor, Hyalomma, Rhipicephalus)
What is the IH of Equine Puroplasmosis?
Equids
What are the clinical signs of Equine Piroplasmosis?
Theileria equi more severe
Chronic has subtle signs
What is the IH of Feline Babesiosis?
Panthers, cougars
What is the DH of Feline Babesiosis?
Tick species; unknown
What is the cause of human babesiosis in the US?
Babesia microti
What is the DH of Babesia microti?
Tick vector (Ixodes scapularis)
What is the IH of Babesia microti?
Rodent (reservoir)
What is the accidental host of Babesia microti?
Humans