CHAPTER 7 (Viral disease) Flashcards
(15 cards)
Etiology:
* Caused by PRRS virus (PRRSV), an Arterivirus in the family Arteriviridae.
- Two major genotypes:
- Type 1 (European)
- Type 2 (North American)
Porcine Reproductive and Respiratory Syndrome
Clinical Signs
Respiratory Form (mostly in weaners and
growers):
* Labored breathing (thumping)
* Coughing
* Fever, lethargy
* Poor growth, uneven weight gain
* Increased secondary infections (e.g.,
bacterial pneumonia)
Reproductive Form (mostly in sows):
* Abortions, early farrowing
* Stillbirths, mummified fetuses
* Weak piglets with high mortality
* Irregular estrus cycles
Porcine Reproductive and Respiratory Syndrome
Etiology:
* Caused by Porcine Circovirus Type 2 (PCV2).
* Often associated with co-infections (e.g., Mycoplasma hyopneumoniae, PRRS virus, Streptococcus suis).
* Stressor factors (e.g., poor hygiene, overcrowding, weaning) exacerbate disease.
Porcine Multisystematic Wasting Syndrome
Clinical Sign
Usually seen in pigs 5–15 weeks old:
* Progressive weight loss or wasting
* Enlarged lymph nodes
* Labored breathing, coughing
* Diarrhea
* Pale skin, sometimes jaundice
* Unthriftiness, depression
* Increased mortality (up to 30% or more)
Porcine Multisystematic Wasting Syndrome
Etiology
* Causative Agent: Swine pox virus (SPV)
Swine Pox
Etiology
Causative Agent: Transmissible Gastroenteritis Virus (TGEV)
Transmissible Gastro Enteritis
Clinical Signs
Severity depends on the age of the pigs:
A. Piglets < 2 weeks old:
* Profuse watery diarrhea (yellow to green, foul-smelling).
* Vomiting is common.
* Rapid dehydration, often leading to death within 2–5 days.
* Mortality rate can reach 100% in neonates.
B. Weaned pigs and growers:
* Milder signs: transient diarrhea, vomiting, inappetence.
* Usually recover.
C. Adults (sows and boars):
* Often subclinical or mild transient diarrhea and anorexia.
* Sows may show signs of mastitis or decreased milk production.
Transmissible Gastro Enteritis
Etiology
* Causative Agent: Classical Swine Fever Virus (CSFV)
Classical Swine Fever (Hog cholera)
Etiology
* Causative Agent: African Swine Fever Virus (ASFV)
African Swine Fever
Clinical Signs
Signs vary by virulence of the strain (acute, chronic, or subclinical forms) and the age/immunity of pigs.
Acute CSF (highly virulent strains):
* High fever (40.5–41.5°C / 105–107°F).
* Depression, huddling, anorexia.
* Conjunctivitis, nasal discharge.
* Diarrhea or constipation.
* Purple skin discoloration (especially ears, abdomen, inner thighs).
* Neurological signs: ataxia, tremors, convulsions.
* High mortality: up to 100% in naïve herds.
Classical Swine Fever
Clinical Signs
A. Peracute form (highly virulent strains):
* Sudden death with few/no signs.
B. Acute form:
* High fever (up to 42°C / 107.6°F).
* Anorexia, lethargy.
* Cyanosis, especially of ears, snout, abdomen, and legs.
* Hemorrhages: visible on skin and internal organs.
* Vomiting, diarrhea (may be bloody).
* Abortion in pregnant sows.
* Death in 7–10 days, with mortality up to 100%.
African Swine Fever
- A member of the Poxviridae family, Suipoxvirus genus.
- DNA virus that is species-specific (only infects pigs).
- Often occurs in conjunction with Hematopinus suis (hog louse), which acts as a mechanical vector.
Swine Pox Virus
- An enveloped, single-stranded RNA virus from the Coronaviridae family.
- Closely related to Porcine Respiratory Coronavirus (PRCV), which can confer partial cross-protection.
Transmissible Gastroenteritis Virus
- A small, enveloped, single-stranded RNA virus in the genus Pestivirus, family Flaviviridae.
- Closely related to Bovine Viral Diarrhea Virus (BVDV) and Border Disease Virus (BDV)
Classical Swine Fever Virus (Hog cholera)
- A large, enveloped, double-stranded DNA virus.
- Only member of the Asfarviridae family.
- Infects domestic pigs and wild suids (like warthogs and bush pigs).
- Extremely resistant in the environment and in processed pork products.
African Swine Fever Virus
