Topic 5: Foetopathy of swine caused by parvoviruses (SMEDI)

Question 1

Pathogen

Answer 1

Family, Sub Family, Parvoviridae, parvovirinae

Porcine Parvovirus -1 PPV1

21-25 nm, icosahedral, NON enveloped
ssDNA (+/-) (Parvus, latin for small)

3 structural proteins

X in dividing cells

nuclear inclusion bodies

one serotype
a disease of 1st pregnancy gilts

worldwide

Stable in environment, resistant to heat, ph and solvents, disinfectants

Genus Parvovirus
HA, shed in faeces, enteric and systemic disease in dog and cats
repro failure in pigs, SMEDI

Question 2

Epi of PPV1

Answer 2

spread though feaces and alive of infected pigs

mechanically via fomites, semen of infected boars (shed through semen for couple of weeks post infection)

can survive 4 months in environment (fomites)

endemic inmost herds may disappear spontaneously in herds under 100 sows

maternal immunity: protects for 6 months, seropositive o r 9-10 months

almost all females are infected before their 2nd pregnancy, develop LIFELONG IMMUNITY, prevents transplacental infection –> disease of 1st parity pigs

Question 3

Pathogeneis of PPV1

Answer 3

PO, reaches gut, enters blood, viremia, foetal damage , SMEDI

1º x site is SI

Question 4

CS of PPV1

Answer 4

SMEDI, still birth, mummification, embryonic death, infertility

Pregnant sows: return to oestrus (3-8 weeks post breeding), aborton, rescued litter size
(unlikely to be ppv if more than 8 live piglets

Embryo / Foetus

• <30 days, death, resorption
• 30-70 days, mummification(calcification of Skelton at d35, not resorption)
• over 70, weak or mummified. some born alive but persistently infected, some mount an immune response, clear the virus and healthy at birth

PPV occsionally cause respiratory and vesicular disease in adult pigs, systemic in neonates

litters of varying sizes, including mummified and still born, to 1st party gilts are hallmarks of PPV1

Question 5

Pathology HP , PPV

Answer 5

abnormal foetal development

piglets at different stages of infection, SMEDI

Question 6

Dx of PPV

Answer 6

IF, testing of ab in tissue secretions, blood, body fluids of aborted foetus

virus isolation from lung of mummified

precolostral ab in stillborn piglets

PCR

HA, tissue homogenates

Serology- HAI, VN, ELISA

Question 7

Prevention and control of PPV1

Answer 7

natural seroconversion, lifelong immunity
inactivated (live), monovalent and combined vaccines
- at 6 months, 1-2 times prior to breeding, repeated annually
postpone 1st mating if detected

Question 8

Ddx of PPV

Answer 8

PRRS, Leptospiroosis, Brucellois, CSF, Aujeskys, FMD