Pseudorabies and Canadian Swine Industry Challenges

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Questions and Answers

Which animal is resistant to Foot-and-Mouth Disease?

Cattle

Ruminants

Horses (correct)

Pigs

What is the typical incubation period for Foot-and-Mouth Disease?

3-10 days

1-7 days

2-14 days (correct)

5-15 days

What is the typical incubation period for ASF after exposure to a tick?

10 to 14 days

5 to 19 days (correct)

1 to 3 days

3 to 7 days

Which of the following are common clinical signs of chronic ASF?

Painless joint swelling and low fever Signup and view all the answers

How long can pigs shed infectious doses of Foot-and-Mouth Disease?

28 days Signup and view all the answers

Which of the following is a direct transmission route for ASF?

Contact with infected ticks Signup and view all the answers

What was the economic impact of the last Foot-and-Mouth Disease outbreak in Canada?

$6.6 billion Signup and view all the answers

What is the most common post mortem lesion observed in ASF cases?

Hemorrhagic spleen Signup and view all the answers

What is the primary mode of transmission for Foot-and-Mouth Disease?

Respiratory droplets and nose-to-nose contact Signup and view all the answers

How long can Foot-and-Mouth Disease viruses survive in the environment?

Long time, very resistant to disinfectants Signup and view all the answers

What is the primary impact of a foreign animal disease outbreak on the Canadian swine industry?

Shut down of exports due to economic concerns Signup and view all the answers

Which of the following zoonotic diseases is transmitted via urine and infected water?

Leptospirosis Signup and view all the answers

Which foreign animal disease is considered the most likely threat to the Canadian pig population?

Pseudorabies Signup and view all the answers

Which of the following conditions can be clinically indistinguishable from acute ASF?

Classical swine fever Signup and view all the answers

Which disease is NOT classified under vesicular diseases?

Bovine Viral Diarrhea Signup and view all the answers

What is a common initial symptom of Foot-and-Mouth Disease in pigs?

Acute lameness Signup and view all the answers

How is the Pseudorabies virus typically excreted from infected animals?

In large quantities in saliva and nasal secretions Signup and view all the answers

What characteristic of the Pseudorabies virus allows for distinguishing infected animals from those vaccinated?

Marker vaccines that affect natural antibody levels Signup and view all the answers

What is the status of excretion of Foot-and-Mouth Disease virus by an infectious pig?

400M infectious doses/day Signup and view all the answers

Which of the following vesicular diseases is transmitted by Rhabdoviridae?

Vesicular Stomatitis Signup and view all the answers

What potential consequence may arise from the mental health concerns attributed to foreign animal disease outbreaks?

Decreased farmer well-being and decision-making Signup and view all the answers

Which of the following is NOT a method of transmission for the Pseudorabies virus?

Persistent latency in the environment Signup and view all the answers

What is a significant post-mortem finding associated with Pseudorabies in infected animals?

Presence of rabies-like neurological signs Signup and view all the answers

Which animals are considered dead-end hosts for the Pseudorabies virus?

Cats and dogs Signup and view all the answers

What is a key factor that influences the epidemiology of Pseudorabies?

The virus's ability to persist in latent states Signup and view all the answers

What is the primary route of transmission for Pseudorabies among pigs?

Respiratory route Signup and view all the answers

Which group of pigs shows the highest mortality rate after exposure to Pseudorabies?

Neonates Signup and view all the answers

Which clinical sign is NOT typically associated with Pseudorabies infection in adult swine?

Tremors and convulsions Signup and view all the answers

What type of lesions are identified histologically in Pseudorabies infected tissue?

Intranuclear inclusion bodies Signup and view all the answers

Which of the following species is considered a dead-end host for Pseudorabies?

Dogs Signup and view all the answers

What is the significance of the tonsil in the pathogenesis of Pseudorabies?

It acts as a major site for viral replication. Signup and view all the answers

What is the expected result of Pseudorabies infection in a piglet that develops clinical signs?

Immediate death Signup and view all the answers

Which clinical sign would likely NOT be observed in grow-finish pigs infected with Pseudorabies?

Sudden death Signup and view all the answers

Which method of diagnosis is NOT commonly used for Pseudorabies?

Blood cultures Signup and view all the answers

Which of the following statements about Pseudorabies vaccination efforts is accurate?

Pseudorabies has been eradicated from the commercial herd in the U.S. Signup and view all the answers

What is the primary method used to control the spread of diseases like Seneca Virus A in the affected animal populations?

Humane destruction of all infected and exposed animals Signup and view all the answers

What type of virus is responsible for Hog Cholera?

Flaviviridae, Pestivirus Signup and view all the answers

Which clinical sign is commonly associated with Hog Cholera?

Button ulcers in cecum Signup and view all the answers

What differentiates African Swine Fever from other viral diseases in pigs?

It can have asymptomatic carriers in wild pigs Signup and view all the answers

Which of the following is NOT a common clinical sign of African Swine Fever?

Decreased appetite without weight loss Signup and view all the answers

What is the primary factor contributing to the varying virulence of different isolates of African Swine Fever?

Genetic differences among the viral strains Signup and view all the answers

What significant veterinary action is taken as part of zoning measures in disease control?

Establishing defined areas that are either infected or disease-free Signup and view all the answers

Which of the following does NOT belong to the systemic viral diseases present in swine?

Seneca Virus A Signup and view all the answers

Which of the following diseases in swine is associated with sudden outbreaks of high mortality?

African Swine Fever Signup and view all the answers

What type of virus is known to cause 'turkey egg kidneys' in infected pigs?

Pestivirus Signup and view all the answers

Study Notes

Major Concerns for the Canadian Swine Industry

Economic losses are possible during a foreign animal disease outbreak
Significant decrease in exports, which make up 50% of Canada's production
Stricter regulations on farm-to-farm movement of pigs to prevent disease spread
Challenges in disposing of large number of carcasses

Pseudorabies (Aujeszky's Disease)

Caused by suid herpesvirus 1 (suHV-1) which persists in latent state
Causes subclinical infection in carrier animals
Moderate resistance outside of the host, likely surviving no more than 2 weeks
Can be destroyed by disinfectants
Marker vaccines differentiate between natural virus antibodies and vaccine titres

Pseudorabies - Epidemiology

Excreted through saliva, nasal secretions, urine, and feces for up to 2 weeks
Persists in the tonsil for several weeks
Remains latent in the central nervous system for many months
Other animals are dead-end hosts, leading to fatal neurological disease and severe itching
Found in most countries except Canada, Greenland, and Australia
Eradicated from commercial herds in the USA in 2004

Pseudorabies - Transmission

Highly contagious and spreads quickly through herds
Primarily transmitted through the respiratory route via oral-nasal secretions
Disseminated transplacentally, through milk, vaginal mucosa, semen, and potentially airborne
Can be spread through fomites

Pseudorabies - Pathogenesis

Varies depending on viral strain, pig age, and viral load
Replication begins in the upper respiratory tract epithelium
Spreads to lymph nodes, then to the central nervous system, particularly the spinal cord and brain
Forms intranuclear inclusion bodies in the CNS and tonsil, the primary site of infection
Causes inflammation and necrosis in the respiratory tract, bronchial tree, alveoli, endometrium, vagina, placenta, and fetuses

Pseudorabies - Clinical Signs

Three overlapping syndromes: Central Nervous System, Respiratory, and Reproductive
Age-dependent and dependent on infectious dose and strain
Neonates present with high mortality (up to 100%), usually within 1-3 days
Weaned pigs display similar signs, but mortality is typically lower
Grow-finish pigs primarily exhibit respiratory symptoms, including coughing, sneezing, nasal discharge, and weight loss
Adult swine experience pyrexia, anorexia, and respiratory signs like sneezing, coughing, and labored breathing

Pseudorabies - Diagnosis and Control

History of death in cats and dogs, high mortality in neonates, abortions, and neurological signs can be indicative
Diagnosis is confirmed through various tests like Fluorescent Antibody, Immunohistochemistry, Polymerase Chain Reaction, and Histology
Eradication in the US was achieved in 2004 through the use of a DIVA vaccine
Treatment is not available

Vesicular Diseases

Include Foot-and-Mouth Disease (FMD), Swine Vesicular Disease (SVD), Seneca Virus A, Vesicular Stomatitis, and Vesicular Exanthema
Characterised by vesicular lesions on the skin, tongue, and hooves
Pose significant threats to the swine industry

Foot-and-Mouth Disease (FMD)

Caused by a virus in the Picornaviridae family
Many strains exist, which differ antigenically, leading to limited cross-protection
Transmitted through respiratory droplets and nose-to-nose contact
Airborne transmission can reach up to 50 km
Affects most ruminants and pigs
Last outbreak in Canada occurred in Saskatchewan from 1951 to 1952, affecting 25 farms
Estimated economic impact of $6.6 billion in today's dollars, excluding trade implications

FMD - Transmission

Pigs have a lower infectious dose for oral exposure compared to ruminants
Relatively resistant to airborne infection
Highly contagious and highly resistant to disinfectants
Can survive in the environment for extended periods
Carrier stage in cattle up to 3.5 years, small ruminants up to 9 months, and pigs up to 28 days
Incubation period ranges from 2 to 14 days

FMD - Clinical Signs

Acute lameness often observed within 1-5 days after infection
Pyrexia (fever), excessive salivation, and chomping of the mouth
Small, blanched lesions on the skin progress into vesicles on the lips, tongue, teats, and udder
High morbidity, with mortality around 5%, but higher in piglets

FMD - Control

Humane destruction of infected and exposed animals
Tracing to identify potential sources of infection
Quarantine measures and restricted movements
Zoning to establish disease-free areas

Seneca Virus A

Causes vesicular lesions

Systemic Viral Diseases

Hog Cholera (classical swine fever, CSF), African Swine Fever (ASF), Japanese B encephalitis, Blue eye disease, Teschen and Talfan

Hog Cholera (CSF)

Caused by a Pestivirus in the Flaviviridae family
Strains vary in virulence
Eradicated from the USA in the 1970s
Clinical signs vary with viral virulence
Possible symptoms include lethargy, depression, high fever, conjunctivitis, constipation, watery diarrhea, vomiting, weakness, posterior paresis, cyanosis, and sudden death

Hog Cholera - Lesions

Button ulcers in the cecum
Enlarged spleen with infarction
"Turkey egg kidneys"
Petechiae in kidneys and lymph nodes

African Swine Fever (ASF)

Caused by a DNA virus in the Asfarviridae family
Transmitted by arthropods, primarily ticks
Highly contagious and affects both domestic and wild pigs
Isolates vary in virulence, with high virulence strains causing mortality up to 100%
Highly resistant to environmental factors, including disinfectants, but can be killed by high temperatures
No treatment or vaccine available in North America

ASF - Transmission

Direct contact through oronasal secretions
Indirect transmission through uncooked garbage, fomites, tick bites, and biting insects
Found in all bodily tissues and fluids
Incubation period estimated at 5 to 19 days

ASF - Clinical Signs

Acute disease characterized by a short incubation period, high fever, anorexia, erythema, cyanosis, recumbency, bloody diarrhea, abortion, and sudden death
Chronic disease presents with multi-focal erythema, low fever, painless joint swelling, emaciation, and eventual death

ASF - Post Mortem Lesions

Highly variable, but common findings include hemorrhagic spleen (enlarged, friable, dark red/black), lymph nodes, kidneys, and heart

ASF - Differential Diagnosis

Clinically indistinguishable from classical swine fever
May also present with similar symptoms to acute Porcine Reproductive and Respiratory Syndrome (PRRS), porcine dermatopathy and nephropathy syndrome, erysipelas, salmonellosis, actinobacillosis, Glasser's disease, pseudorabies, warfarin poisoning, heavy metal toxicosis, thrombocytopenia, and generalized septicemic or hemorrhagic conditions

Zoonotic Diseases

Many potential pathogens exist, but most are not prevalent or rarely cause problems in North America
May pose a risk to young children and individuals with compromised immune systems

Leptospirosis

Caused by the bacteria Leptospira pomona
Transmitted through infected water and urine
Enters through mucous membranes, skin, or eyes
Human infection can cause splenomegaly, hepatitis, and nephritis
Prevention includes vaccinating sows against Leptospirosis and using gloves for assistance with dystocia

Streptococcus

May cause zoonotic concerns, particularly in individuals with weakened immune systems

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Description

This quiz explores the major concerns affecting the Canadian swine industry, particularly regarding Pseudorabies (Aujeszky's Disease). It highlights economic impacts, disease transmission, and regulatory challenges faced by producers. Delve into the epidemiology of the disease and its effect on livestock health and trade.