Tick Transmitted Diseases Flashcards
Which Tick disease can cause bone marrow suppression over time?
Ehrilichia canis
How is E. canis usually diagnosied
WIth a combination of clinical findings and seeing Morula in monocytes.
(If you dont see the morula does not rule out infection)
Which tick transmits E. canis?
Brown dog tick (Ripicephalus sanguineus)
Where is this tick usually found?
Throughout the United States but prefers warm climates (southeastern and southwestern states)
What does the Acute phase of E. canis entail?
8-20 days after inoculation: fever lethargy and inappetence most common. Can also see Thrombocytopenia and thrombocytopathia.
T/F During the acute phase of E. canis the spleen, liver and lymph nodes might become enlarged?
True
T/F The acute phase of E. canis can spontaneously recover after 2-4 weeks.
True- they eliminate infection or remain subclinically infected.
What is the main feature of the subclinical phase of E. canis
It can be detected on lab tests but has no clinical signs.
What are the main features of hte chronic phase of E. canis?
It has simailar signs as acute phase plus Bone marrow hypoplasisa (pancytopenia), protein losing nephropathy, marked lymphocytosis and hyperglobulinemia.
What do you visualize in blood smears to diagnose E. canis?
Morulae visualized in monocytes or lymphocytes. However if you dont see them does not mean there is no infection.
What does antibody testing of E.canis indicate?
Indicates exposure to organism but not necessarily active infection. There is a potential for false negative results with acute infections.
which test is the gold standard for E. canis testing?
Indirect immunoflourescent antibody test. IgG antibodies are a reliable indicator of E. canis infection.
What are the IFA testing procedures for acute E. canis infection?
Two consecutive IFA tests 7-14 days apart when acute exposure is suspected. A four fold increase in antibody titers is suggestive of acute and active infection.
T/F an ELISA snap can be used to dx E. canis?
True- it is a qualitative tests and assess for IgG antibodies. Compared to IFA the sensitivity of the 4Dx is 97%
T/F Whole blood PCR is more sensitive for actue E. canis infections but serology is more sensitive for chronic infections
True PCR can detect E. canis DNA as early as 4-10 days post-inoculation.
What is the treatment for E. canis?
Doxycycline with minocycline or chloramphenicol can be used as an alternative.
T/F Dogs with severe chronic E. canis will always respond to treatment.
False- they may never respond to treatment or cytopenias may take months to respond. Can cause permanent damage to bone marrow.
Which dog breed is most suspectable to E. canis and may have a worse prognosis?
German Shepard dog
In what WBC does Ehrlichia ewingii replicate?
Replicates in neutrophils and delays neutrophil apoptosis.
Which tick transmits E. ewingii
The lone star tick )Amblyomma americanum) Found throughout south-central and southeastern parts of the US.
T/F E. ewingii can cause acute and chronic disease
Flase- can only cause acute disease.
When do signs for E. ewingii develop?
Typically 3-4 weeks after inoculation.
What are some clinical signs that dogs might present with?
Fever, lethargy and inappetence. POLYARTHRITIS
thrombocytopenia (mild to moderate). lymphadenomegaly.
Can also show no clinical signs.
How is E. ewingii diagnosed?
Morulae may be observed in granulocytes (cannot be distinguished from A. phagocytophilum morulae)
Can do an ELISA but will cross-react with E. canis and E. chaffeensis.
Whole blood PCR= helps confirm active infection and differentiate species.
T/F Clinical disease of E. ewingii is often milder than that of E. canis
true
What is the treatment for E. ewingii
Doxy
What is the characteristic of Anaplasma phagocytophilium?
Granulocytic anaplasmosis in dogs.
Which ticks primarily transmit A. Phagocytophilium?
Ixodes scapularis )northeastern and upper midwestern US) and Ixodes pacificus (western US)
Which other disease is co-infection common with A. Phagocytophilium?
Borrelia burgdoferi
What are the main clinical features of A. Phagocytophilium?
The majority of infected dogs do not show clinical signs. Chronic infection HAS NOT been documented. Main potential CS is fever, lethargy and inappetence with polyarthritis.
What is the main diagnosis tools for A. Phagocytophilium?
Point of care ELISAs, IFA, and PCR.
What is the treatment for A. Phagocytophilium?
Doxy but some dogs and cats may spontaneously clear the infection.
Which tick is the primary trasmitter of Rickettsia rickettsii (RMSF)?
Dermacentor andersoni (wood tick) in western US and Dermacentor variabilis (american dog tick) in mid west to eastern US
What cell does Rickettsiae replicate in?
Endothelial cells of smaller arteries and venules.
Due to the replication what does Ricettsii cause?
Initiates vasculitis –> activates platelets and coagulation system –> consumption of platelets and coagulation factors. Thrombocytopenia also occurs due to immune-mediated platelet destruction.
What is the clinical feature of rickettsii seen in most patients?
Patients may hemorrhage excessively or experience thrombosis. The skin, brain, heart and kidneys are most adversely affected.
What is the incubation period of R. rickettsii?
ranges between 2-14 days.
What are the clincal signs of RMSF?
Arhralgia and spinal hyperesthesia. Fever lethargy, inappetence, thrombocytopenia, cutaneoups edema and hyperemia and possible neruo signs
What test is used to dx RMSF
Serologic testing (IFA)W
When should treatment start? What is main treatmetn
Early recognition and treatment is key to reducing mortality so start tx if you suspect as the test takes time to come back. Treat with Doxy (can use chloramphenicol and enrofloxacin)
What Tick spreads Hepatozoon americanum and what is unique about its transmission?
Amblyomma maculatum (Gulf Coast tick) spread by ingestion of the tick
What are the main clinical findings of H. americanum?
Severe muscle wasting (along temporal muscles) generalized hyperesthesia (pain and excessive sensitivity) Stiff gait, purulent ocular discharge.
What is unique about the CS of H. americanum?
they can wax and wane in severity
What changes to the bone will be seen with H. americanum?
Periosteal bone proliferation. Lesions occur more frequently along the proximal bones of the limbs.
What is the most reliable way to diagnose H. americanum?
Skeletal muscle biopsy. Will consist of “onion” cysts and marked pyogranulomas myositis
What is the treatment for H. americanum?
TCP combination therapy: Trimethoprim-sulfonamide, clindamyin, and pyrimethamine for 2-week duration. After TCP decoquinate (anticoccidial drug) is stared for 2 years.
T/F no treatment is effective at eliminating the tissue stages of H. americanum and clinical relapses are common
True- Decoquinate helps to prevent clinical relapses
What trick transmitts Babesia canis?
Brown dog tick.
What does Babesia canis look like on blood smear?
It is a large, piriform-shaped organism existing singly or paired within erythrocytes.
What does Babesia gibsoni look like on a blood smear?
Small protozoan organisms existing singly within erythrocytes with ring like configurations.
What dictates the course and severity of Babesia in the host?
Depends on the species and strain of Babesia and the host’s immunocompetency.
What CS are present for uncomplicated disease?
Fever, inappetence, and lethargy. Thrombocytopenia, hemolytic anemia (extravascular and intravascular)
What CS are present for the complicated C. Babesiosis?
Similar signs as uncomplicated plus acute renal failure, neuro signs, hepatic injury, acute resp distress, red biliary syndrome.
What two dog breeds often have subclincal infection of Canine Babesiosis?
Greyhounds and American pit bull terriers.
Which test is the most sensitive way to detect infection and allow for Babesiosis species identification?
PCR
