170. Chronic respiratory disease of poultry (mycoplasmosis), infectious synovitis.

Question 1

Avian Mycoplasma species?

Answer 1

Avian Mycoplasma species

• Approximately 25 species
• Mycoplasma species of domestic poultry
• Chicken, turkey: M. gallisepticum (MG), M. synoviae (MS), M. meleagridis (MM), M. iowae
• Goose, duck: M. anserisalpingitis, M. anseris, M. anatis, M. cloacale (Acholeplasma species)
• Pigeon: M. columorale, M. columbinasale, M. columbinum

Question 2

Mycoplasma Synoviae ethiology?

Answer 2

Mycoplasma synoviae

Etiology

• Culture requirements:NAD, cystein, porcine serum
• Antigen structure: vlhA gene and vlhA pseudo genes ➝ recombination
• Virulence of the strains are variable
• Host species: chicken, turkey (pheasant, quail, partridge, goose)

Question 3

Mycoplasma synoviae Epidemiology?

Answer 3

Epidemiology

• Global distribution
• Prevalent: except primarily breeding stocks
• Horizontal transmission
• Direct and indirect contact
• Wild birds
• Fomites
• Airborne dust

• Vertical transmission

• More in acute and less in chronic infections
• Monitoring of breeding stocks are important

• Intercurrent infections

• Viruses: NDV and IBV ➝ vaccine strains
• Bacteria: E. coli, M. meleagridis, M. gallisepticum, S. aureus

Question 4

Mycoplasma synoviae Pathogenesis?

Answer 4

Pathogenesis

1. Horizontal transmission: upper respiratory tract/conjunctiva, Vertical transmission or other pathogens/stressors
2. Attach to epithelial cells and propagate ➝ surface erosion ➝ affect cell-mediated immune system
3. Entering non-phagocytic host cells and variable expression of surface proteins
   - Resisting host defence
   - Resisting antibiotic therapy
   - Establishing generalised and/or chronic infection

• Incubation period is variable based on: strain virulence, complicating infections, environmental and stress factors
• Often subclinical infections
• Incubation period
• Vertical transmission: 6 days
• Horizontal transmission: 2-20 days

Question 5

Mycoplasma synoviae Clinical signs and Pathology?

Answer 5

Clinical signs, Pathology

• Infectious synovitis
• Air sacculitis
• Egg apex abnormality (EAA) even 4%
• Egg production and quality drops
• Reduced growth
• Synergism other pathogens
• Trade issues
• Morbidity
• Infectious synovitis: 5-15% (2-75%)
• Airborne infection: 90-100%

• Mortality: 1-10% (cannibalism in turkeys)

Question 6

Diagnosis of Mycoplasma synoviae?

Answer 6

Diagnosis

• Right sample: acute, chronic infection

• Direct: trachea/chona swab (joint fluid, oviduct)
• Indirect: blood
• Sample number and sampling frequency: flock diagnosis ≠ individual diagnosis
• Day old chicks: difficult to diagnose
• Specificity and sensitivity of applied method
• Combination of different test methods: indirect and direct method
• Diagnostic methods
• Indirect methods: serology ➝ rapid slide agglutination test, ELISA, haemagglutination-inhibition test
• Direct methods: PCR (conventional, real-time), isolation
• DIVA (differentiating infected from vaccinated animals)
• Genotyping: for molecular epidemiology purposes

• Dry swab ➝ isolation

Question 7

Waterfowl Mycoplasmosis Species?

Answer 7

Waterfowl Mycoplasmosis

Species

• M. anserisalpingitidis ➝ goose (duck)
• M. anatis ➝ duck (goose)
• M. anseris ➝ goose
• M. cloacale ➝ goose, duck (turkey)
• Acholeplasma species ➝ goose and many animals

Question 8

Waterfowl Mycoplasmosis Epidemiology?

Answer 8

Epidemiology

• Pathogenicity and virulence of the strains probably different
• Factors may lead to clinical signs
• Stress during reproductive period
• Large scale and intensive management

• Vertical transmission: sperm, egg and horizontal transmission: fertilisation, faeces

Question 9

Clinical signs, Pathology of Waterfowl Mycoplasmosis?

Answer 9

Clinical signs, Pathology

• Cloaca inflammation
• Phallus inflammation, testis atrophy
• Oviduct and vagina inflammation
• Decrease in egg production
• Embryo mortality
• Respiratory diseases
• M. anseris
• Primarily infect geese
• Similar to M. anserisalpingitidis: phallus inflammation, embryo mortality, peritonitis, air sacculitis

• M. cloacale

• Commensal
• Genital inflammation, embryo mortality

• M. anatis

• Primarily infect ducks
• Neurological disorders, encephalitis, meningitis, retrograde movement, torticollis
• Weak legs
• Air sacculitis
• Diarrhoea
• Embryo mortality, reduced hatchability

• Acholeplasma species

• Embryo mortality
• Air sacculitis, peritonitis in young birds

Question 10

Diagnosis of waterfowl Mycoplasmosis?

Answer 10

Diagnosis

• Indirect methods using serology ➝ currently not available
• Direct methods ➝ right sample (phallus lymph, cloaca swab, sperm, oviduct, air sac), PCR, isolation
• Genotyping: molecular epidemiology

Question 11

Control of Mycoplasma of waterfowl?

Answer 11

Control

• Temporary: more difficult to treat with antibiotics than the other Mycoplasma species, broad antibiotic resistance (most effective:

Tiamulin, Tylvalosin, Doxycycline)

• Long term

• Free breeding flocks: difficult because of the production system in semi wild bird species
• Vaccination: no registered vaccines, only autovaccines