Marek's Disease - these two words can strike fear into the hearts of pet chicken flock owners and farmers alike. There has never been an effective treatment - until now.
In this post:
What is Marek's Virus?
Marek's is an avian herpes virus that causes one of the most frequent cancers in animals. It is endemic, and according to accredited sources is present in upwards of 80% of backyard poultry flocks. Much like herpes in humans, a bird can be infected with the Marek's virus and never develop symptoms - only 3-4% of birds will ever develop symptoms. Once a bird becomes symptomatic, it is then referred to as Marek's Disease, which is most common before 16 weeks of age but can be triggered at any age. While there are devastating virulent strains with high mortality rates, they are rare and most are mild with a high percentage of birds being asymptomatic.
What causes Marek's Disease?
In birds that have been exposed and infected with Marek's virus, disease is most often triggered by their immune system being compromised. It can be another illness, such as cocidiosis, parasites, respiratory issues, fowl pox, or any number of other health stressors. It can be environmental stress, such as agressive flockmates, excessive heat or cold, or food competition. Good husbandry is also vital, as an evironment that is overcrowded, has poor ventilation, or has a high fecal load do not support healthy immune systems. Once one bird develops active disease, the virus is being actively shed, and other flockmates also often develop disease.
Marek's Symptoms
In the classic form, Marek's Disease will cause inflammation and tumors in the nerves, spinal column and brain. In this form, birds will become paralyzed in the legs, or wings or may develop head tremors. Tumors can develop in internal organs including the heart, ovary, liver and lung, as well as in the eyes, in the feather follicles, or in the nervous system. Affected birds can have symptoms of general depression, weight loss, and lethargy due to generalized illness.
The signs and symptoms of Marek’s disease vary depending on the form of disease present. Even within one form of the disease, signs can vary depending on how the disease manifests in each individual bird. ( Marek's disease, Colorado State University, Veterinary Diagnostic Labratories)
Prevention
Treatment for Marek's start with prevention by maintaining a healthy environment that supports immune health:
- Keep the flock's environment clean, regularly cleared of feces, and treated for common parasites.
- Ensure birds have adequate space and are separated from overly agressive flockmates to prevent being picked on.
- Feed good quality poultry feed and provide plenty of fresh, clean water.
The advice that is most commonly given is to euthanize all symptomatic birds, close the flock permanently to any new birds or any birds leaving, and keep them as stress free as possible for the remainder of their lives. While this is an effective way of stopping the spread in a pet flock, it doesn't actually treat the disease. It is endemic, and no matter how long you wait to get new chickens, it can come back again.
Although there is a Marek's vaccine, it is only effective in preventing the development of symptoms. It does not prevent a bird from being infected and then shedding the virus to other birds. Because of this and the expense of the vaccines available to backyard flock owners, most breeders choose not to vaccinate as it can mask an active carrier. Instead, most breeders choose to breed for natural resistence.
Baicalin Treatment Protocol
Baicalin is the first known effective treatment for Marek's and Avial Leukosis Virus (ALV) to be accessible to backyard poultry flocks and breeders. Numerous clinical studies have shown that it both stops active outbreak and disease, and prevents further spread and infection when administered as a part of the flock's daily diet.
References
Latest Insights into Marek’s Disease, 2020
2020 Mar 10;12(3):647. doi: 10.3390/cancers12030647