31. Bacterial & protozoan infections as a cause of infertility in gilts & sows (aetiology, clinical signs, diagnosis, differentials, treatment, prevention)

What are the groups of pathogens causing infertility on gilts and sows?

• Group 1: Ordinary microorganisms that are present in majority of pigs, but rarely cause problems

• Group 2: Rarely causes clinical disease, but spread rapidly

• Group 3: Infrequent infections that result in severe reproductive loss

What are examples of group 1 pathogens?

1. E.coli

2. Erysipelas

3. Klebsiella

4. Salmonella

5. Pasteurella

6. Glaesserella parasuis

7. Streptococcus

What are examples of group 2 pathogens?

Viruses - PRRS; SMEDI, PPV

What are examples of group 3 pathogens?

1. Brucella

2. Leptospira

3. Chlamydia

4. Mycoplasma

5. Toxoplasma

How do bacteria gain access to pigs during farrowing?

Through an open cervix if the sow farrows in a contaminated environment

What is the most obvious clinical sign of bacterial infection in swine?

Vulva discharge, which must be differentiated from physiological discharge (pro-estrus, estrus)

What are examples of diseases caused by group 1 pathogens?

1. Puerperal metritis

2. Endometritis

3. Pyometra

What is puerperal metritis in swine?

A severe bacterial metritis involving large amounts of smelly fluid and decomposing foetal membranes in the uterus

What are the clinical signs of puerperal metritis in swine?

Fever, malnourished piglets, decreased fertility

What is endometritis in swine?

A less severe uterine infection that is economically significant and may cause conception failure and early embryonic death

What are the clinical signs of endometritis in swine?

Low fever, mild discharge, often clinically normal but pregnancy terminates

What is pyometra in swine?

A condition where the uterus is closed after a bacterial infection and pus accumulates, typically caused by group 1 pathogens (e.g., E.coli, streptococci, staphylococcus, Erysipelas)

What pathogen causes meningitis, septicaemia, and abortion in swine and is zoonotic?

Streptococcus suis

How is Streptococcus suis transmitted?

Through ingestion, inhalation, and nose-to-nose contact

What are the clinical signs of Streptococcus suis infection in swine?

White, purulent vaginal discharge and reduced conception rate (50-60%)

What is the treatment for Streptococcus suis in swine?

Penicillin

What is the prevention for Streptococcus suis in swine?

Vaccination 2-5 weeks before breeding

What pathogen causes arthritis, diamond skin lesions, fever, and abortion in swine?

Erysipelas, caused by Erysipelothrix rhusiopathiae

What is the common source of Erysipelas in swine?

It commonly resides in the tonsillar tissues

How is Erysipelas treated in swine?

Penicillin-streptomycin

What is the prevention for Erysipelas in swine?

Vaccination and avoiding stress

What condition occurs post-breeding when the uterus is closed and pus accumulates?

Post-breeding pyometra

What is the cause of post-breeding pyometra in swine?

Group 1 pathogens like E.coli, streptococci, and staphylococcus

What is the treatment and prevention for post-breeding pyometra in swine?

Antibiotics (ATB) for treatment and appropriate hygiene for prevention

What is Brucellosis and why is it significant?

A zoonotic infection that affects pigs, leading to severe reproductive loss and transmission from boars to other pigs and humans

What are the species of Brucella affecting swine?

1. Brucella suis (biovars 1, 2, 3)

2. Brucella abortus

What are the main transmission routes for Brucella suis?

Boars (main source of infection), foetus, placenta, vaginal discharge, semen, milk, nose, mouth, vertical transmission

What is the pathogenesis of brucellosis?

Intracellular bacteria, causing systemic bacteraemia, affect genital organs, chronic, lifelong infection

What are the clinical signs of Brucella suis infection in pigs?

Abortion, infertility, epididymitis, clinical orchitis, poor reproductive performance, arthritis, lameness, paralysis of hind legs in piglets

How is brucellosis diagnosed?

1. CS, isolation

2. Culture (blood agar)

3. Microscopy (stamp stain)

4. Serology (CFT, Rose Bengal test, ELISA, Agglutination test)

When is best to collect blood from a sow when testing for Brucellosis?

7-14 days after abortion

What is the treatment for pigs infected with Brucella suis?

Cull all positive sows and boars, as they serve as a permanent source of infection

What is the prevention strategy for Brucella suis in pigs?

Serological monitoring, leaving infected areas empty for six months, and no vaccine available for pigs

What are the species of Leptospira affecting swine?

1. L. pomona

2. L. bratislava

3. L. canicola

4. L. icterohaemorrhagiae

How is leptospirosis transmitted?

Urine of affected animals, rodents, carrier pigs, ingestion, inhalation, venereal, per-cutaneous, MM in contact w/ urine-contaminated bedding, water, soil, food.

Zoonotic

What is the pathogenesis for leptospirosis?

Affinity for kidneys, liver, pregnant uterus → kidney failure, hepatitis, necrosis, abortion

What are the clinical signs of leptospira infection in swine?

1. Acute: fever, decreased appetite, blood in urine, jaundice, death

2. Chronic: abortions (2-3 weeks before term), mummification, stillbirths, mucopurulent vaginal discharge

How is leptospirosis diagnosed?

MAT, PCR, dark field microscopy, serology from urine

What is the treatment for leptospira infection in swine?

Tetracycline

What is the prevention for leptospira in swine?

Vaccination before breeding, contraindicated in pregnant pigs

Which species of Chlamydia affects swine?

Chlamydia suis

How is Chlamydia suis transmitted?

Through placental and uterine discharges during parturition or abortion, ingestion, inhalation, and venereal transmission

What is the pathogenesis of Chalmydia suis?

Cause bacteraemia

• Diffuse inflammatory response

• Thrombotic vasculitis & tissue necrosis

• Death of foetus

  • Impairment of maternofetal nutrient & gaseous exchange

  • Disruption of hormonal regulation of pregnancy

What are the clinical signs of Chlamydia suis in swine?

Enteritis, arthritis, pneumonia, abortions, weakness, stillbirths, poor condition in piglets

How is chlamydiosis diagnosed?

Serology, microscopy, bacterial isolation

What is the treatment for Chlamydia suis in swine?

Tetracycline, which interferes with replication but does not kill the bacteria

What is the prevention for Chlamydia suis in swine?

Disinfect after abortion, no vaccine available

What is the transmission route for Mycoplasma suis?

Through infected blood (Haematopinus suis), vertical and horizontal transmission

What is the pathogenesis of Mycoplasma suis?

Affects RBCs in liver → haemolysis

What are the clinical signs of Mycoplasma suis infection in pigs?

Weakness and anaemia in piglets, reproductive failure, delayed oestrus, embryonic death in sows

How is Mycoplasma suis diagnosed?

Indirect hemagglutination, ELISA, PCR, Giemsa-stained blood smears

What is the treatment for Mycoplasma suis in pigs?

Oxytetracycline for 5 days

How is Toxoplasma gondii transmitted in swine?

Faecal-oral, transplacental, zoonotic

What are the clinical signs of Toxoplasma gondii infection in swine?

Mild and asymptomatic, abortion, absorption, stillbirth, weak piglets

How is Toxoplasma gondii diagnosed?

PCR, serology, IFAT, ELISA, CFT, PM (muscle cysts)

What is the prevention for Toxoplasma gondii in swine?

Prevent access of cats to pig-feed or pig areas

What precautions against pyometra can be given after assisting in delivery?

ATB (entering birth canal contaminates with faeces, dirt, bacteria)