What do you do to prevent losses due to Mycoplasma?
Dr Ellis Draaijer DVM, Poultry Business Development Manager, Kernfarm
It is widely known that Mycoplasma gallisepticum (Mg) is one of the most prevalent diseases that affects gamebirds. Once a flock is infected, no treatment can free that flock from it completely, and the disease can flare up when birds are stressed. The bacteria therefore causes significant economic loss, and health and welfare issues. While no one approach and no veterinary intervention (vaccines, antibiotics etc) will offer 100% success, there are many things one can undertake to keep the infection out or minimize clinical impact.
It is so important that the industry keeps communicating openly on the topic of Mycoplasma in order to increase the overall awareness of the infection, to learn from each other by exchanging experiences, and to reduce spreading and clinical disease. Openness around positive flocks enables specialised veterinarians to offer their support in the earliest stages of a potential outbreak and minimize impact on animal welfare and economic parameters.
Recently, a new, injectable, inactivated Mg-vaccine was registered for chickens in the UK, which, in the absence of an available registered product, is allowed for use in game birds. The scientific research behind the vaccine proves that using it alongside good husbandry and biosecurity is a powerful preventive tool against Mg.
Clinical signs
Mycoplasma usually firstly infects the bird’s upper respiratory system: the nose, sinuses and throat. Signs of the disease we need to look out for include coughing, sneezing, swollen eyes, and thick heads caused by severe inflammation of one of the sinuses (sinusitis). Affected birds often have wet shoulders from wiping away discharge from their eyes and nose. The affected flock will also have poor growth and increased mortality.
The disease is more difficult to manage than many other bacterial infections, because it spreads both vertically from hens to egg and chicks, and horizontally between birds (also from wild birds to game birds). Furthermore, we have to deal with ‘carriers’, birds that were infected at some point and carry Mycoplasma in their respiratory tract, but appear 100% healthy. Game keepers cannot see that there is an infection at that moment and when these birds become stressed (caused by being taken off pellet feed, bad weather, etc.), or when other respiratory infections like Infectious Bronchitis Virus, avian metapneumovirus, Pasteurella, or E. coli join in, these birds often do get sick, and will start shedding (spreading) Mycoplasma.
Preventive measures
Knowing if Mg is present in your flock is crucial; only then you can implement the right preventive strategies to decrease the impact of the disease, minimise shedding and spreading on the farm, and to other farms or shoots. Different methods are available, and you will need to consult with your veterinarian to choose the right method. In general, we can choose between two methods: we can look for Mycoplasma gallisepticum (the bacteria itself) or check if the birds have Mg-antibodies in their blood (serology).
Important preventive measures include; purchasing only Mg-free (tested) stock, asking for a recent Mg-status report when buying new birds, using all-in, all-out systems, optimal biosecurity and hygiene practices, regular clinical check-ups of a flock for signs of disease, taking periodical samples and swabs for Mg-PCR, and blood samples. Optimizing biosecurity practices and hygiene is of paramount importance when dealing with flocks. For example, cleaning and disinfecting boots and overalls regularly, avoiding direct contact with wild birds, and offering shelter for the birds in bad weather.
New vaccine in the UK
The new inactivated (= killed) Mg vaccine (learn more) has been registered and used safely and effectively in chickens (layer and reproduction), in several European countries for many years. The vaccine is most often used in flocks that are Mg-negative in antibody tests but are at risk of becoming infected. Inactivated vaccination can, however, also be used in a flock with antibodies.
In chickens, inactivated vaccines have repeatedly shown to produce a high antibody response, and substantially reduce Mg-associated clinical signs, Mg shedding from infected to healthy birds in the flock, and vertical Mg transmission through the egg to the chick.
Testing also shows that this type of killed vaccine induces an antibody response in the blood, and similar benefits, in gamebirds as well as in chickens. With no registered alternative available and now also registered in the UK, it’s (off-label) use in game birds is growing.
While vaccines will never be 100% effective in preventing infection, research shows that the impact and spread of the disease will be much lower if administered. Optimizing biosecurity and minimizing stress therefore remain highly important in keeping Mycoplasma at a low level, and these measures determine the level of success that can be reached with vaccination.
Like to know more about preventing Mycoplasma in your flock? We are open for a chat!