Agriculture Reference
In-Depth Information
Because the vaccine is a live virus, anecdotal evidence seems to point to the vaccine
itself as the cause of the spreading. A great controversy exists over how deadly it really
is in North America in particular locations. Many raisers are questioning the need for
the sudden increase in large-scale vaccinations, similar to the outcry in some areas over
the increase in required human vaccinations. In regions where great numbers of birds
are affected, it is nearly impossible to raise chickens without providing vaccination. As
of the writing of this topic, I have never dealt with Marek's on my farm, other than in
birds brought in that have been vaccinated.
The average backyard raiser should not run away panic-stricken, thinking that they
cannot keep chickens without vaccinating for Marek's. Instead, talk to some longtime
poultry fanciers in the area first and see what they have to say. Many backyard flocks
with limited exposure to poultry from off their property have no problems. Taking your
fowl to a fair or exhibition does put them at risk for exposure, however. A first-time
raiser in fresh facilities with no intention of bringing in adult birds or entering their birds
in a fair will probably never deal with the disease, as long as they start with day-olds.
Marek's most often shows up as tremors, paralysis of half the body, and stiffness.
Symptoms
The disease manifests itself in a number of different ways. The typical presentation is
called range paralysis; the bird has neurological problems that result in tremors, be-
comes paralyzed on one side of the body, and lays stiff and emaciated in one place until
it dies. Once the disease is established on your farm, it will affect every bird in the flock.
Vaccination
Vaccination seems to be the only proven way to prevent Marek's. Many hatcheries vac-
cinate their baby chicks with a shot in the neck as they leave the hatchery. You cannot
vaccinate once the disease is symptomatic; the bird has to be vaccinated before it reaches
