Classical African Swine Fever Virus

What is classical swine fever also known as?

Hog cholera

How is the acute form of classical swine fever manifested?

High fever

Depression

Lack of appetite

Reddened skin (hyperemia) or cyanosis

Internal hemorrhages

Convolusions

Death

High mortality

Which form of classical swine fever can older pigs recover from?

Chronic form

What are the three forms of classical swine fever?

Acute, subacute, and chronic

Which form of classical swine fever is characterized by high fever, internal hemorrhaging, skin hyperemia or cyanosis, and high mortality?

Acute form

What does the subacute form of classical swine fever look like?

Less severe clinical signs (fever, hemorrhage, skin hyperemia/cyanosis, etc.)

Prolonged duration

Lower mortality

What does chronic classical swine fever look like?

Can be difficult to recognize/diagnose

Decreased appetite, depression, fever, poor growth, skin lesions

Signs wax and wane for weeks to months

If classical swine fever is suspected or diagnosed, what should be done immediately?

Should be reported

Reportable animal disease!

What family is classical swine fever in?

Flavivirdiae

What is the morphology of the classical swine fever virus?

Enveloped, single-stranded, positive-sense RNA

What does flavi- mean?

Yellow

When was classical swine fever first reported in the U.S.?

1833 as hog cholera

What happened in relation to classical swine fever in 1978?

U.S. was declared hog cholera free

When was the U.S. declared free of classical swine fever?

1978

What does the USDA APHIS surveillance plan for classical swine fever include surveillance for?

Swine with CSF clinical signs

Sick pigs submitted to a veterinary diagnostic lab

Pigs condemned at slaughter by the Food Safety and Inspection Service

Feral swine collected by wildlife services

How is classical swine fever transmitted?

Direct contact

Fomites

Vectors

In utero infections

What do in utero infections of classical swine fever result in?

Persistently infected piglets

What can classical swine fever virus be spread through?

Secretions

Excretions

Semen

Blood

What is the most common method of transmission for classical swine fever?

Oronasal transmission, direct or indirect

What are piglets that were infected in utero with classical swine fever called?

Shaker piglets

How long do piglets persistently infected with classical swine fever shed the virus?

6-12 months

How long do persistently infected piglets with classical swine fever have viremia?

Their entire life

What are clinical signs of classical swine fever?

Poor reproductive performance

Abortions

Piglets born with a congenital tremor and persistently infected

What might be the only sign of a herd infected with a less virulent classical swine fever virus?

Poor reproductive performance

What is one way that classical swine fever is transmitted and spread?

Feeding uncooked swill and trash from infected pigs

Feeding swine untreated food wastes

How long can classical swine fever survive in pork and processed pork products when refrigerated and when frozen?

Refrigerated - months

Frozen - years

What is the incubation period of classical swine fever?

2-14 days

3-7 days in acute cases

When do animals with acute classical swine fever die?

Within 1-2 weeks

What type of disease is caused by classical swine fever?

Neurologic, respiratory, and reproductive

What lesions are seen in acute classical swine fever?

Hemorrhage -> skin discoloration, cyanosis of extremities

Swollen and hemorrhagic lymph nodes

Petechial or ecchymotic hemorrhages on serosal and mucosal surfaces

What is the most common lesion seen in acute classical swine fever?

Hemorrhage resulting in purple, discolored skin and cyanosis of extremities

What lesion does classical swine fever cause in the GI tract?

Button ulcers

What lesions can be caused by classical swine fever?

Hemorrhage (acute)

Tonsilitis

Splenic infarcts

Button ulcers in the GI tract

What is required to make a classical swine fever diagnosis?

Detection of antibodies or the virus itself

What does the FDA use to diagnose classical swine fever?

PCR and tonsils

What tissue is used by the FDA to make a classical swine fever diagnosis?

Tonsils

What is the main test and tissue used to make a classical swine fever diagnosis?

PCR, tonsils

When do antibodies for classical swine fever develop?

Around 3 weeks post-infection

What viruses have cross-reactivity with the classical swine fever virus?

Bovine viral diarrhea virus

Border disease virus

What do classical swine fever vaccines require to be used?

USDA approval

When are classical swine fever vaccines generally used?

To assist in outbreak response efforts

What is the treatment for classical swine fever?

No treatment, just supportive care

What type of vaccine is the classical swine fever virus vaccine?

Modified live vaccine

Where is the classical swine fever vaccine prohibited?

CSF-free areas

What is the biggest drawback of the classical swine fever vaccine?

Not DIVA

What happens when a classical swine fever outbreak occurs?

Slaughter of all pigs on affected farms

Safe disposal of carcasses and fomites

Thorough disinfection

Designation of infected zone with control of pig movements

Detailed epidemiological investigation

Surveillance

What policy was used to eliminate classical swine fever from North America?

Stamping out policy

What can be done to prevent classical swine fever?

Good biosecurity practices

Cooking food scraps for feeding pigs

Control of animal imports

Decontamination and disposal of foreign garbage

Why is classical swine fever economically significant?

It has high morbidity and mortality

Highly contagious

What categories are classical swine fever strains divided into?

High, moderate, and low virulence strains

What affects the severity of classical swine fever?

Viral isolate

Age of pig

Immune status

Dose

Health of pig

Where does classical swine fever replicate?

In monocytes, macrophages, and endothelial cells