Unit 3 - Swine Viral and Vesicular Diseases Flashcards
What are the two major exotic viral diseases posing a threat to the swine industry in the US?
Hog cholera
African Swine Fever
What are Hog cholera and ASF characterized by?
High fever
Lymphoid involvement
High mortality
Skin erythemas to effusions
What is the etiologic agent of hog cholera?
Pestivirus
Where has hog cholera been eliminated from?
The US, Canada, and several European countries
What are the hosts of hog cholera?
Domestic swine and wild boar
How is hog cholera transmitted?
Direct contact via the oro-nasal route
Garbage feeding
Personnel, equipment, pets, birds, and arthropods
Where is the primary site of invasion for hog cholera? Viremia and spread to where?
Primary site of invasion is the tonsillar crypt with viremia and spread to the lymphoid tissues.
How long is the incubation period for hog cholera?
2-4 days
What clinical signs are associated with hog cholera?
High fever
Excitable at first followed by apathy and anorexia
Marked ocular discharge: severe conjunctivitis
Hind leg incoordination, huddling, diarrhea, dyspnea, recumbency with paddling
Congenital tremors in piglets with cerebellar hypoplasia
Morbidity and mortality for hog cholera is ____ with survival only ____-____days PI. In subacute HC, pigs
show less severe signs of disease and succumb within ___ days. In chronic disease, pigs may
survive ____ days or more.
100%
10-20
30
100
What cells does hog cholera target?
Endothelial cells
What lesions are associated with hog cholera?
Disseminated petechiae and ecchymoses especially in the skin, larynx, bladder, brain, and kidney (turkey-egg kidney). Multifocal infarcts of the margin of the spleen are characteristic but inconstant. Button ulcers (because of infarcts) of the colon. Lymphopenia
How is hog cholera diagnosed?
PCR on the tonsil
FA on tissues
SN test: Best in the chronic forms
Virus isolation
T/F: Hog cholera is not reportable, but ASF is.
False - Hog cholera is… I assume ASF would be too but it hasn’t been in the US
What ddx should be considered with hog cholera?
ASF, salmonellosis, erysipelas
What is the etiologic agent of ASF?
Asfarvirus
What animals serve as reservoirs for ASF?
Wart hogs, giant forest hogs, and bush pigs in Africa
T/F: Asfarvirus survives for prolonged periods under most environmental conditions especially when protected in meat or blood.
True
T/F: All secretions and excretions from acutely ASF infected domestic pigs are infectious
True
How is ASF transmitted?
Ticks or hematophagous insects
Introduction of infected swine or indirectly through contaminated personnel and equipment.
How long is the incubation period for ASF?
1-4 days
What clinical signs are associated with ASF?
Fever: 105 - 108 F
Hyperemia of the skin
Abortions
Mortality in 100% of virulent forms
What is the pathogenesis of ASF?
Enters via mouth or URT and spreads to tonsils then spreads quickly to the mandibular lymph nodes and throughout the body via blood and lymph.
When injected (tick bites) the virus spreads rapidly to the RES and lymphocytes.
What gross lesions are associated with ASF?
Severely hemorrhagic and edematous lymph nodes (look like hematomas, often with little
discernable lymphoid tissue).
Splenomegaly
Petechial hemorrhages throughout the body.
Kidneys may be very hemorrhagic.
How is ASF diagnosed?
PCR assay
Clinical signs and lesions
How is ASF controlled?
Slaughter all infected and exposed swine
Restrict swine and pork movement
Thorough cooking of garbage before feeding it to swine
What is foot AND mouth disease?
A vesicular disease affecting cloven-hoofed animals including wild and domestic ruminants
and swine.
T/F: FMD has the broadest host range of the vesicular diseases affecting domestic animals and is the most easily transmitted
True
T/F: In addition to cloven-hoffed animals, elephants, hedgehogs, horses, and even humans have been infected with FMD.
FALSE BITCH FALSE!!!! HORSEYS CANNOT GET FMD
T/F: FMD is said to be one of the most economically important worldwide when one includes the adverse effects on trade.
True
What is the etiologic agent of FMD?
Aphthovirus (picornavirus)
How are the majority of FMD cases transmitted?
transmission is thought to be through infected saliva
During the early febrile period what contains the FMD virus?
All tissues, excretions and secretions contain the virus including semen