Mycoplasma driving you crazy?

MYCOPLASMA REDUCTION

PROGRAMME:

AVENUES FOR FUTURE RESEARCH

Hilda Joubert and Louis Maartens

Fact

Once a bird is infected with Mycoplasma, it is considered chronically infected for life and

subsequent stress may cause disease

Research objectives should focus on

keeping flocks free of infection (difficult)

AND/OR

Reducing the negative economic impact of

mycoplasma on South African poultry

Control strategies for Mycoplasma

infections in commercial poultry include

three general approaches (Kleven, 2008)

Maintaining flocks

free of infection

Biosecurity and effective monitoring

Medication

Useful in preventing clinical signs and

economic losses but cannot be used to

eliminate infection from a flock

Vaccination

Useful long-term solution where

maintaining flocks free of infection is

not feasible, especially on multi-age

commercial egg production sites

Short term objective

Obtain information on the mycoplasma

situation in South Africa

Short term activities

Determine the prevalence and distribution of mycoplasma in the avian breeder flock population in South Africa

A comprehensive coordinated approach to determine prevalence and distribution is needed and should include

• Culture and identification of mycoplasma isolated from

infected flocks

• Confirm identity of mycoplasma with species-

specific mycoplasma polymerase chain reaction

• Determine the prevalence of vertical transmission

• Serological monitoring of unvaccinated flocks

Short term activities

Isolation and characterisation of avian mycoplasmas

or variants involved in field infections

Aligning these mycoplasmas to international

reference strains which will give valuable information

on divergent (new species in same genus that

evolved in parallel) or convergent (new relationships

built on old abilities) evolutionary patterns

Short term activities

Establish if infections with specific variants of

mycoplasma are related to clinical signs or decreased

egg production or downgrading of meat-type birds

Medium term objectives

Establish the efficacy of antibiotics against

Mycoplasma species/variants in South Africa

Susceptibility of mycoplasma, circulating in the field, to

antimicrobials should be determined

Targeted use of a suitable antibiotic for limited periods

assists in overcoming production losses

The following must be considered

• Overuse leads to resistance development which

can result in serious consequences for future

disease control

• Antibiotic residues especially in egg products

• Dose dependent embryo toxicity

Medium term activities

Long term objective

Maintaining flocks free of infection

Long term activities

Will require an integrated approach to the entire

biosystem

• Good biosecurity and decontamination

• Maintaining replacements from mycoplasma-

free sources in a single-age, all-in all-out

management system

• Effective monitoring systems are necessary

aspects of this program

Vaccination may be a suitable long term tool to minimise infection but challenge studies to evaluate long-term efficacy of vaccines used in South Africa is needed

• Vaccination can interfere with surveillance

• Vaccination can be used for control of

mycoplasma where stringent biosecurity measures are not feasible and antibiotic residues in meat or egg products are problematic

Long term activities

To Conclude

It will not be a broad and straight path

We will certainly encounter difficulties

Guidance from experts will be

needed

It will take time

We might have to deviate from set

paths

There will be limitations

Trouble will be found along these

avenues

Involvement from the industry is crucial

It will cost something

The aim is to achieve the goals