L41: VBD and viruses in equine

What agent causes Potomac Fever?

Neorickettsia risticci

What type of agent is Potomac Fever?

Trematode

What vector(s) or transmission route(s) spread Potomac Fever?

Aquatic snails

What cells or tissues are affected by Potomac Fever?

Monocytes • Macrophages • Enterocytes

What diagnostic test(s) are used for Potomac Fever?

PCR on blood or feces

What are the clinical signs of Potomac Fever?

• Profuse watery diarrhea

• laminitis

• Anorexia

• Colic

• Fever

What is the treatment for Potomac Fever?

• IV oxytetracycline I

• V fluids

• NSAIDS

• Cyrotherapy (laminitis)

What is the prevention/control for Potomac Fever?

Remove from water sources

Isolate cases

What prognosis note is listed for Potomac Fever?

Guarded prognosis if complication like severe laminitis develop

What agent causes Lyme Disease?

Borelia burforferi

What type of agent is Lyme Disease?

Spirochete (Bacteria)

What vector(s) or transmission route(s) spread Lyme Disease?

Ixodes tick

What cells or tissues are affected by Lyme Disease?

1. Leukocytes

2. Synovial lining cells

What diagnostic test(s) are used for Lyme Disease?

1. PCR of bursal fluid

2. OpsC test

What are the clinical signs of Lyme Disease?

1. Neurborreliosis

2. Cranial nerve deficits

3. Neck and back stiffness

4. Uveitis

5. Cutaneous pseudolymphoma

6. Stiffness

7. Shifting leg lameness

8. Muscle Wasting

9. Hyperesthesia

10. Nuchal bursitis

What is the treatment for Lyme Disease?

1. Seropositive horses with clinical signs with other potentials ruled out receive treatment

2. Penicillin

3. Ceftiofur

4. Tetracyclines (nephrotoxicity and NEVER give IM)

What is the prevention/control for Lyme Disease?

1. Tick control (early spring and fall greatest risk)

2. Canine lyme vaccines off-label (2-3 doses)

Is Lyme Disease zoonotic according to the table?

Zoonotic

What agent causes Granulocytic Anaplasmosis?

Anaplasma phagocytolium

What type of agent is Granulocytic Anaplasmosis?

Gram-negative obligate intracellular bacterium

What vector(s) or transmission route(s) spread Granulocytic Anaplasmosis?

Ixodes tick

What cells or tissues are affected by Granulocytic Anaplasmosis?

Leukocytes

What diagnostic test(s) are used for Granulocytic Anaplasmosis?

1. Thrombocytopenia

2. Neutropenia

3. Active Infection: PCR on blood during fever; Giemsa stain of blood

4. Chronic infection: IFAT on serum; Can remain negative for up to 3 weeks

What are the clinical signs of Granulocytic Anaplasmosis?

1. Fever

2. Stiffness

3. Limb edema

4. Anorexia

5. Icterus

what will be seen on CBC in a horse with Granulocytic Anaplasmosis?

1. Severe leukopenia

2. Thrombocytopenia

3. Mild anemia

4. Neutropenia

What is the treatment for Granulocytic Anaplasmosis?

1. Oxytetracycline IV

2. Doxycycline/Minocycline

3. Immunity is approximately 1 year

What is the prevention/control for Granulocytic Anaplasmosis?

1. Tick control

2. Synthetic pyrethroids

3. Cypermethrin

4. Regular inspection for ticks

How long after a tick bite does bacteremia develop in Granulocytic Anaplasmosis?

Bactermia develops 5-7 days after tick bite

What immune response is caused by Granulocytic Anaplasmosis?

Causes a TH1 immune response

Is Granulocytic Anaplasmosis zoonotic according to the table?

Zoonotic

What agent causes Rickettsia?

Rickettsia raoulti

What type of agent is Rickettsia?

Gram-negative obligate intracellular bacterium

What vector(s) or transmission route(s) spread Rickettsia?

Ticks

What cells or tissues are affected by Rickettsia?

Endothelial Cells

What diagnostic test(s) are used for Rickettsia?

1. ELISA

2. PCR

What are the clinical signs of Rickettsia?

Often asymptomatic

What is the treatment for Rickettsia?

Oxytetracycline

What is the prevention/control for Rickettsia?

Tick control

Is Rickettsia zoonotic according to the table?

Zoonotic

What agent causes Piroplasmosis?

1. Babesia cabelli

2. Theileria equi

What type of agent is Piroplasmosis?

Protozoa

What vector(s) or transmission route(s) spread Piroplasmosis?

Ticks

What cells or tissues are affected by Piroplasmosis?

Erythrocytes

What diagnostic test(s) are used for Piroplasmosis if a horse is being imported or exported?

cELISA and IFAT

what diagnostic tests are used for chronic or subclinical cases of piroplasmosis?

cELISA and CFT

what diagnostic test is used for acute cases of piroplasmosis?

combination of blood smear, PCR, and paired serology (second sample 14-21 days later)

What are the clinical signs of Piroplasmosis?

1. High fever

2. Severe anemia

3. Jaundice

4. Lethargy

5. Reduced appetite

What is the treatment for Piroplasmosis?

1. Imidocarb dipropinate IM (CANNOT GIVE TO DONKEYS)

2. Pre-treatment with antispasmodics may be necessary

what is the protocol time for treatment for piroplasmosis caused by T. equi?

4 injections at 72 hour intervals

what is the protocol time for treatment for piroplasmosis caused by B. caballi?

2 injections 24 hours apart

What is the prevention/control for Piroplasmosis?

1. Report all positive and suspicious cases

2. Isolate and quarantine all animals brought to US

What reporting status is listed for Piroplasmosis?

Reportable disease

When do clinical signs of Piroplasmosis usually appear after infection?

Clinical signs usually appear 5-28 days post infection

What agent causes Equine Infectious Anemia Virus?

Lentivirus equinfane

What type of agent is Equine Infectious Anemia Virus?

Retrovirus

What vector(s) or transmission route(s) spread Equine Infectious Anemia Virus?

1. Horseflies

2. Deer flies

3. Iatrogenic

4. Mom to foal

5. Veneral

What cells or tissues are affected by Equine Infectious Anemia Virus?

1. Circulates in plasma

2. Monocytes

3. Macrophages

What diagnostic test(s) are used for Equine Infectious Anemia Virus?

Coggins Test (serologically convert 16-42 days post-infection)

What are the clinical signs of Equine Infectious Anemia Virus?

1. Fever

2. Depression

3. Jaundice/pale MM

4. Petechiations

5. Ecchymoses

6. Edema

What is the treatment for Equine Infectious Anemia Virus?

None

What is the prevention/control for Equine Infectious Anemia Virus?

1. Test Yearly

2. Vector control

3. Do not share needles

What carrier status is listed for Equine Infectious Anemia Virus?

Infected horses become life long carriers requiring euthanasia or strict isolation

What types of hemolysis are listed for Equine Infectious Anemia Virus?

Intravascular and extravascular hemolysis

What platelet effect is listed for Equine Infectious Anemia Virus?

Immune-mediated destruction of platelets

What agent causes Equine Viral Arteritivirus?

Equine arteritis virus (EAV)

What type of agent is Equine Viral Arteritivirus?

Enveloped positive-sense ssRNA virus (Arteriviridae)

What vector(s) or transmission route(s) spread Equine Viral Arteritivirus?

1. Respiratory secretions/aerosols during acute infection

2. venereal transmission via semen from persistently infected stallions

What cells or tissues are affected by Equine Viral Arteritivirus?

Early: CD14+ monocytes and some T lymphocytes

What diagnostic test(s) are used for Equine Viral Arteritivirus?

RT-PCR

What are the clinical signs of Equine Viral Arteritivirus?

1. Many horses are asymptomatic

2. Fever

3. depression

4. anorexia

5. nasal discharge

6. cough

7. conjunctivitis/lacrimation

8. periorbital and limb/abdominal edema

9. abortion in mares

10. severe disease/death can occur in young foals

What is the treatment for Equine Viral Arteritivirus?

None

What is the prevention/control for Equine Viral Arteritivirus?

1. Vaccinate in horses

2. Biosecurity of incoming animals

What reservoir/shedding note is listed for Equine Viral Arteritivirus?

Carrier stallions are a major reservoir and can shed virus in semen for prolonged periods

What agent causes African Horse Sickness?

African horse sickness virus (AHSV)

What type of agent is African Horse Sickness?

Segmented double-stranded RNA Orbivirus

What vector(s) or transmission route(s) spread African Horse Sickness?

Culicoides biting midges

What cells or tissues are affected by African Horse Sickness?

Vascular endothelial cells especially capillaries in the lungs and heart

What diagnostic test(s) are used for African Horse Sickness?

RT-PCR on EDTA blood

What are the clinical signs of African Horse Sickness?

1. High fever

2. depression

3. severe dyspnea

4. frothy nasal discharge

5. pulmonary edema

6. cardiac form causes edema including characteristic supraorbital swelling

7. Hydropericardium/pleural effusion may be present.

What is the treatment for African Horse Sickness?

None

Supportive care

What is the prevention/control for African Horse Sickness?

1. Vaccine in endemic regions

2. Vector control

3. Quarantine

What reporting status is listed for African Horse Sickness?

Notifiable disease

What agent causes Hendravirus?

Hendra virus

What type of agent is Hendravirus?

Enveloped negative-sense ssRNA virus

What vector(s) or transmission route(s) spread Hendravirus?

Bats

What cells or tissues are affected by Hendravirus?

1. Strong tropism for vascular endothelial cells

2. also affects pulmonary tissue

3. can be neurotropic

What diagnostic test(s) are used for Hendravirus?

1. PCR

2. Serology

3. Immunochemistry

What are the clinical signs of Hendravirus?

1. Acute fever with rapid deterioration

2. respiratory distress/tachypnea

3. pulmonary edema

4. frothy nasal discharge

5. tachycardia

6. depression/anorexia

What is the treatment for Hendravirus?

None

What is the prevention/control for Hendravirus?

Yearly booster

What reporting status is listed for Hendravirus?

Reportable

Is Hendravirus zoonotic according to the table?

Zoonotic

What agent causes Glanders?

Burkholderia mallei

What type of agent is Glanders?

Gram-negative facultative intracellular bacterium

What vector(s) or transmission route(s) spread Glanders?

Contact with skin lesions or inhaled/ingested secretions

What cells or tissues are affected by Glanders?

1. Respiratory mucosa/lungs

2. Skin

What diagnostic test(s) are used for Glanders?

1. Screening: complement fixation test (CFT)

2. Competitive ELISA/Western blot can improve specificity

3. PCR and culture can confirm clinical cases

4. Mallein testing is used in some control programs/regions.

What are the clinical signs of Glanders?

1. Nasal, pulmonary and cutaneous forms

2. Fever • purulent nasal discharge

3. nodules and ulcers of nasal mucosa

4. pulmonary nodules/pneumonia

5. Acute disease may be rapidly fatal

6. chronic infection may persist.

What is the treatment for Glanders?

None

What is the prevention/control for Glanders?

1. Rapid detection

2. isolation/quarantine

3. euthanasia/culling of confirmed cases

4. No vaccine