Reproductive diseases

Question 1

What are two causes of reproductive diseases in pigs?

Answer 1

1. leptospirosis

2. porcine parvovirus

Question 2

What people are affected by leptospirosis? What are the clinical signs?

Answer 2

Women of child bearing years

bacteremia, abortion, flu-like, cyclical fever

Question 3

What are the signs of leptospirosis in pigs?

Answer 3

largely subclinical and endemic

Question 4

Why does the importance of leptospira vary with geographic region?

Answer 4

serovar

local maintenance host

Question 5

Leptospira has an affinity for what organ?

Answer 5

kidney

Question 6

Swine are susceptible to which serovars of leptospira interrogans?

Answer 6

all

Question 7

What are the maintenance hosts for lepto serovar pomona?

Answer 7

swine
skunk
racoon
opossom

Question 8

What are the maintenance hosts for lepto serovar bratislava?

Answer 8

swine

horse

Question 9

What are the characteristics for infection in a maintenance host (lepto)

Answer 9

1. efficient tranmission
2. high insidence
3. chronic disease
4. persistence in kidney
5. low Ab response
6. few organisms

Question 10

What are characteristics of infection in an incidental host?

Answer 10

1. low susceptibility
2. high pathogenicity
3. acute disease
4. sporatic transmission
5. short renal infection
6. MARKED AB response
7. many organisms

Question 11

What are the methods of transmission of lepto?

Answer 11

horizontal

vertical (venereal, transplacental)

Question 12

Environmental survival of lepto is enhanced by what?

Answer 12

1. moisture and warmth
2. wildlife acess
3. stagnant water
4. susceptible to dessication

Question 13

What isthe pathogenesis of leptospira?

Answer 13

1. penetrate mucus membranes
2. brief bacteremia
3. prompt agglutinating Ab
4. clearance from most systemic organs
5. Persistence in kidneys and genital tracts (immunologically privileged)
6. transplacental infection if preg

Question 14

What are the clinical signs of lept infection in incidental infections?

Answer 14

1. bacteriemia

2. transient anorexia, pyrexia, listlessness

Question 15

What are the clinical signs of infection in sows/gilts with pomona?

Answer 15

abortion, stillborns, live weak piglets

Question 16

What are the clinical signs of infection with bratislava in pigs/gilts

Answer 16

infertility (sometimes later term abortion)

Question 17

What is the pathology of incidental lept infection

Answer 17

mild dz
petechial hemorrhage
mild renal damage, liver necrosis

Question 18

What is the pathology of maintenance/chronic lepto?

Answer 18

kidneys: diffuse focal interstitial nephritis
in fetus:
1. edema in body cavities,
2. petechial hemorrhage,
3.focal liver necrosis (uncommon but suggests lepto)

Question 19

How is leptospira diagnosed?

Answer 19

1. serology

2. demonstration of leptospires or antigen/DNA (special stains, PCR)

Question 20

What are issues with using serology for leptospira diagnosis?

Answer 20

serology!
cross reactions common
issue with vaccination pig (interpretation)
low titres in maintenance host
4x increase useful but may not occur in maintenance host
high titres rare
low titres in fetal serum could be significant

Question 21

How is leptospira treated and controlled?

Answer 21

1. vaccination–polyvalent bacterin pre-breeding/before infection
2. antimicrobials: streptomycin, oxytetracycline
3. biosecurity (wildlife, rodent control, stagnant water)

Question 22

Where is porcine parvovirus found?

Answer 22

ubiquitous

Question 23

What des porcine parvovirus cause?

Answer 23

embryonic and fetal death

no clinical dz in post natal animals

Question 24

What is the transmission of parvovirus?

Answer 24

tranplacental
semen
(oronasal)

Question 25

What are the features of parvoviridae?

Answer 25

stable
resistant to many disinfectants
remain infectious for 4 months in environent
Cannot get rid of from farm!

Question 26

What are the features of immunity for parvo?

Answer 26

high levels of passive immunity that decrease over 3-6 months
passive antibody interferes with development of active immunity

Question 27

When should gilts be vaccinated against parvo?

Answer 27

prior to conception

Question 28

Are sows generally immune or susceptible to parvo?

Answer 28

immune (active immunity by natural infection persists for life)

Question 29

What is the pathogenesis of parvovirus?

Answer 29

1. virus only replicates for cells undergoing mitosis
2. predilection for fetus
3. predilection for endothelium
4. vascular necrosis

Question 30

Why do transplacental infections after day 70 rarely result in death?

Answer 30

fetal immunocompitence

Question 31

Why does resorption occur before 30 days? Why does mummification occur after?

Answer 31

presence of bones

Question 32

What are the clinical signs of parvo in pre-pubertal pigs?

Answer 32

subclinical

Question 33

What are the clinical signs of parvo in naive preg females?

Answer 33

embryonic death and fetal mummification
small litters
occurance of mummies of variable sizes

Question 34

Why is there the occurrence of mummies of variable sizes with parvo infection?

Answer 34

because parvovirus spreads slowly in utero and sequentially kills fetuses of various ages and sizes UP TO DAY 70

Question 35

Why don’t you typically see mummified fetuses larger than 17mm?

Answer 35

because after day 70 they are immunocompetent

Question 36

How is parvovirus diagnosed?

Answer 36

1. demonstration of antigen or DNA (several mummified fetuses–FAT or PCR)
2. serology–Hemagluttinin inhibition for exposure or maternal antibody decay

Question 37

How is parovirus controlled and prevented?

Answer 37

1. vaccination–multivalent

Question 38

When should animals be vaccinated against parvo?

Answer 38

1. prior to breeding

2. after maternal antibody decay

Question 39

What does parvovirus vaccination prevent? What does it not prevent?

Answer 39

prevents fetal death not infection