11/24/2023:
Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are the most important avian mycoplasma species for the commercial poultry industry from a clinical economical point of view. The first case of MG and MS in poultry was recognized in the 1930s and 1950s respectively. Both mycoplasma species have shown to be of clinical economical relevance for the poultry industry. Both mycoplasma species are transmitted from parent to progeny through the egg (vertical transmission) and by horizontal transmission and after recovery lifelong carriership exist. The control of both mycoplasma species contributes to a more profitable poultry production. Control measures to achieve this however will depend on the prevalence, housing type (single versus-multi age), the geographical area (or integration).
There is no doubt about the clinical-economical relevance of MG. MG is regarded as a risk for commercial poultry especially in the presence of other respiratory agents and is responsible for respiratory disease, increased mortality and increased condemnation rates at slaughter. The clinical economical relevance of MG for the commercial poultry industry has already been recognized 70 years ago and also control programmes have been running since then. MS is different from MG and it has always been present in commercial poultry but the clinical economical relevance has been subject for debate. The developments in diagnostic tests and information from research has given more insight in the clinical economical relevance of MS for the poultry industry. New diagnostic tests and research evidenced the presence of MS strains related to respiratory disease, infectious synovitis, eggshell abnormalities and egg production losses. The worldwide prevalence of these pathogenic strains is not clear. Subclinical infections are still frequently reported. Due to the increasing reports on primary pathogenic MS strains the clinical-economical relevance has become less subject for debate. The latter has also led to more focus on the control of MS in in the poultry industry.
Control MS & MG high prevalence versus low prevalence
MS and MG are transmitted from parent stock to progeny (vertical transmission) and horizontal transmission (direct, indirect contact). The highest rate of vertical transmission occurs in the acute phase of the infection. The approach in control will be different in a situation of low or high prevalence. Slaughter of infected parent stock and biosecurity measurements are important in the control of vertical and horizontal transmission of MG and MS in a low prevalence situation. However slaughtering of infected parent stock in order to cut down the vertical transmission route is not economically sustainable in a situation of high prevalence. In a situation of high prevalence besides a good biosecurity, also antimicrobial treatment and vaccination programmes are important tools in the control of vertical and horizontal transmission. In geographical areas with a high poultry density and the presence of multi age sites MG and MS control will even be a bigger challenge. The approach in the control of MS and MG has to be tailor made and depend on the goals which are feasible under the geographical or integration prevalences.
Diagnostic tests
MG and MS diagnostic tests play an important role to develop further action plans in control strategies. Commercial serological tests (RPA and ELISA-tests) as well as commercial PCR tests, including PCR tests, able to differentiate between vaccine and field strain (DIVA) are available nowadays. Serological tests are the most common used tests as serology is quick and inexpensive. Although more expensive then serology, also PCR tests have also become important in the control of MG and MS. Furthermore, sequence based strain typing techniques are available nowadays which can help you to monitor the persistence or the introduction of new infections which can be of help to monitor the effectiveness of control strategies. PCR Sjaak de Wit Update, November 2023 - 9 tests and molecular typing tests are not always available on location so sampling of FTA cards to perform a PCR test or to perform molecular typing test can be regarded as a good and valuable alternative. In a situation of low prevalence the focus will be on the detection of absence or low level of infection. In a situation of high prevalence diagnostic tests play an important role to monitor the effect of measurements implemented to control MS and MG, to monitor MS or MG status before vaccination or to monitor the status of parent stock by one day old chicks. Sample frequency and size and test- characteristics play a role in the efficiency of the monitoring programmes. Also other factors (circulating Mycoplasma species, used vaccination programme, immunity etc) can be of influence on the performance of the tests. These factors can even differ per geographical area or integration. Also the application of MS and MG vaccines and use of antimicrobial treatments will influence results of diagnostic tests. Animal disease file Mycoplasma
Expertise Royal GD
The approach to managing the vertical and horizontal transmission of MG and MS will depend on the prevalence in a geographic area or within an integration. Diagnostic tests play an important role in the management of MS and MG. Setting up baselines, proficiency testing (PTS) and knowledge about the use and interpretation of diagnostic tests and epidemiology can be of value in setting up monitoring programmes. Our poultry experts Dr. Anneke Feberwee and Prof. Dr. Sjaak de Wit have extensive knowledge of Mycoplasma. Our experts
To be able to perform laboratory tests properly and with reliable results, we would like to refer to the MG and MS products in our PTS and Diagnostics (antigen and anti-serum) program. Since good management and biosecurity is an important key, it is important to keep knowledge up-to-date through Royal GD. To make a good start in determining the nature and extent of the Mycoplasma problem, it is advisable to perform laboratory analyses by a leading laboratory. With our FTA card service, Royal GD can offer an adequate service.
Read in the scientific publication