Marek’s disease is a notifiable animal disease, a viral infection that causes an increase in T-lymphocytes in nerves, intestines, gonads, iris, muscles and skin. Marek’s disease is transmitted by chicken herpesvirus-2, which is found on living vectors such as bird mites and fleas, but is also transmitted to the chicken through contaminated feathers, food, dust and everyday objects.
Frequently affected are young animals up to the 13th week. After that, the likelihood of infection decreases. If the virus is not detected and treated quickly enough, it can spread to the entire chicken population within a few weeks. Infected animals will excrete the viruses for a lifetime through faeces, feathers and skin flakes.
The first signs of this deadly disease are usually coordination disorders, followed by severe paralysis, which is particularly noticeable during escape.
In such cases, slaughter of the chicken and thorough cleaning and disinfection of the house, as well as close observation of the rest of the poultry flock, are recommended.
Preventing the spread of Marek´schen disease is best done by vaccination of the chicks. One should pay attention not to bring the freshly vaccinated animals in contact with unvaccinated chickens, because the vaccine virus is also contagious. After three weeks, the vaccinated young animals can be reassembled without hesitation with non-vaccinated old animals.