We suspect Marek's - what to do?

We have 40 chickens. 3 have the bobble head, going/gone blind, losing weight, etc. symptoms of Marek's. They've probably had it for well over a month and it came on slowly so we didn't realize it. They were supposedly vaccinated, but it doesn't appear that they were.

What do we do? Are the rest of the chickens going to develop it? Do we cull these 3? Do we let them live as long as they can?

We don't know what we're supposed to do and are very worried about losing the entire flock!

Please help!

If it's Mareks then chances are they have all been exposed anyways. Vaccinations will decrease losses but some will still develop it anyways. The philosophy I agree with the most is to cull out any birds that develop symptoms.

In most cases Mareks won't kill your whole flock, you'll just lose a few from time to time.

PC.. if she brings in any new birds will they also catch it since thay have all been exposed? Even from the ones that arent showing any symptoms?

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It's my understanding that Mareks, unlike MG, stays in the soil and on the property for a very long time. Birds that get it and beat it do become potential carriers but as long as they buy vaccinated birds in the future it should be ok.

Quote:
It's my understanding that Mareks, unlike MG, stays in the soil and on the property for a very long time. Birds that get it and beat it do become potential carriers but as long as they buy vaccinated birds in the future it should be ok.

Thanks for the info!

Resolution said use a Cranberry capsules and poke them down with a clove of garlic or an almond... It is said that even the ones with paralysis can come out of it with this treatment... Look up his thread on this.

I am sorry about your birds. I am going through the same thing. I had necropsies done on 2 and they confirmed Marek's. You can vaccinate your birds and there are some that say that it may prevent tumor growth even if they have been exposed. But they will be carriers forever. You will have to vaccinate and seperate all new chicks until the vaccine has time to take hold. Some say 10 days, some say 14. As long as possible is the best of course. ( I just use this as an excuse to brood in my house). They also say a second vaccine may be beneficial.

You can clean your coop with Oxine to help kill the virus. That is my job come payday. Unfortunately for me, mine free range and I can't Oxine the whole pasture, but I will do the coop and the roosts, and the nest boxes.

The really bad thing about this is that I keep looking at my birds expecting to find another one sick. I have lost 3 (maybe 4) so far and have one that is blind in one eye. I have 29 chicks under 8 weeks that were hatched here so I am hoping that the vaccine will keep them safe, even though I was late in giving it. I just couldn't believe that I had Marek's until the second one died. Now I am a believer and I wish I could start over. I have only have chickens for 9 months. A heck of a way to start.

BTW, I tried the cranberry capsule, the hypercium, polyvisol, electrolytes, vitamin E and A, and everything else you can think of. I kept her alive for 3 weeks, but she never got better and was most likely quite miserable. I don't regret trying, but I won't do that to another bird, not for that long.

Here are a few articles I found ..........
http://www.thepoultrysite.com/diseaseinfo/90/mareks-disease
Marek's disease is a Herpes virus infection of chickens, and rarely turkeys in close association with chickens, seen worldwide. From the 1980s and 1990s highly virulent strains have become a problem in North America and Europe.

The disease has various manifestations: a) Neurological - Acute infiltration of the CNS and nerves resulting in 'floppy broiler syndrome' and transient paralysis, as well as more long-standing paralysis of legs or wings and eye lesions; b) Visceral - Tumours in heart, ovary, tests, muscles, lungs; c) Cutaneous - Tumours of feather follicles.

Morbidity is 10-50% and mortality up to 100%. Mortality in an affected flock typically continues at a moderate or high rate for quite a few weeks. In 'late' Marek's the mortality can extend to 40 weeks of age. Affected birds are more susceptible to other diseases, both parasitic and bacterial.

The route of infection is usually respiratory and the disease is highly contagious being spread by infective feather-follicle dander, fomites, etc. Infected birds remain viraemic for life. Vertical transmission is not considered to be important.

The virus survives at ambient temperature for a long time (65 weeks) when cell associated and is resistant to some disinfectants (quaternary ammonium and phenol). It is inactivated rapidly when frozen and thawed.

Signs

Paralysis of legs, wings and neck.
Loss of weight.
Grey iris or irregular pupil.
Vision impairment.
Skin around feather follicles raised and roughened.
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http://www.poultryhub.org/index.php/Marek’s_disease_virus_or_MDV
Marek’s disease virus (MDV) is a highly contagious viral infection that predominantly affects chickens but can also affect pheasants, quail, gamefowl and turkeys. The disease is one of the most common diseases affecting poultry flocks worldwide. Although clinical disease is not always apparent in infected flocks, a subclinical decrease in growth rate and egg production may be economically important. Mortality rates can be very high in susceptible birds. Marek's disease (MD) results in enlarged nerves and in tumour formation in nerve, organ, muscle and epithelial (cells that line the internal and external surfaces of the body) tissue. Clinical signs include paralysis of legs, wings and neck; loss of weight; grey iris or irregular pupil; vision impairment; and the skin around feather follicles can be raised and roughened. Affected birds are more susceptible to other infectious diseases.

MD can look similar to the diseases of lymphoid leucosis and reticuloendotheliosis. The rareness of bursal tumours with MD helps distinguish this disease from lymphoid leukosis. Also, MD can develop in chickens as young as 3 wk of age, whereas lymphoid leukosis typically is seen in chickens >14 wk of age. Reticuloendotheliosis, although rare, can easily be confused with MD because both diseases feature enlarged nerves and T-cell lymphomas (a type of tumour involving white blood cells called T-cells, which are part of the active acquired immunity system) in visceral (soft internal) organs.

MD is caused by a highly cell-associated (virus particles that remain attached to or within the host cell after replication) but readily transmitted herpesvirus. The route of infection is usually respiratory. There are three serotypes of MD virus. Virulent (disease causing) chicken isolates fall into serotype 1. Avirulent (not disease causing) chicken isolates fall into serotype 2. Serotype 3 designates the related avirulent virus that is commonly found in turkeys.

Serotypes are identified by reaction with serotype-specific monoclonal (clones from a single cell) antibodies or by biological characteristics such as host range, pathogenicity (severity of disease), growth rate, and plaque morphology (the physical appearance of laboratory grown viral cultures). Currently, virulent serotype 1 strains are further divided into pathotypes (classification based on the severity of disease caused by that particular strain of virus), which are often referred to as mild (m), virulent (v), very virulent (vv), and very virulent plus (vv+) MD virus strains.

The virus matures into a fully infective, enveloped form in the cells lining the feather follicle and is released into the environment in dander (small scales from feathers which flake off and can become airborne). The virus may also be present in faeces and saliva. When cell-associated, the virus may survive for months in poultry house litter or dust and is resistant to some disinfectants. Infected birds carry virus in their blood for life and are a source of infection to susceptible birds. A recent Poultry CRC epidemiological study has revealed that MDV is less prevalent in the environment than previously thought. However, it is long lasting and remains infective in dust despite wide variations in atmospheric temperature.

Prevention and treatment of Marek’s disease .....

There is no treatment for MD. Vaccination is the central strategy for the prevention and control of MD. While vaccination will prevent clinical disease and reduce shedding of infective virus it will not prevent infection. Cell-associated vaccines are generally more effective than cell-free vaccines because they are neutralised less by maternal antibodies. Over time, increasingly virulent strains of MD virus have emerged, resulting in an ongoing need to develop new vaccines and vaccination programs to combat the disease. It was found that better protection from MD was obtained when certain combinations of serotypes were used together in a vaccine rather than one serotype alone (protective synergism). This phenomena, which is unique to MD and is strongly serotype specific, has led to the development of polyvalent vaccines (vaccines containing more than one vaccine strain).The efficacy of vaccines can be improved by strict sanitation to reduce or delay exposure and by breeding poultry for genetic resistance to MD. Vertical transmission (from parents to offspring) is not considered to be important. Vaccines administered at hatching require 1-2 weeks to produce an effective immunity, therefore exposure of chickens vaccinated at hatching to virus should be minimised during the first few days after hatching. Vaccines are also effective when administered to embryos at the 18th day of incubation. In ovo vaccination (vaccination of the embryo prior to hatching) is now performed by automated technology and is widely used for vaccination of commercial broiler chickens, mainly because of reduced labour costs and greater precision of vaccine administration.

For an existing farm, other than providing clothing for visitors (disposable overalls) and using hard fibre based litter materials (wood shavings), you can reduce the risk by being aware that there is a higher seasonal incidence in Summer/Autumn, which peaks in March. This being so, if you have MDV on your farm, it is important to vaccinate broiler flocks that will mature at the end of Autumn, not just those grown for the Christmas market. Cleaning vehicles between farms, while good biosecurity practice, makes no difference to the spread of MDV. It is far better to spend the money on the disposable overalls than worry about cleaning trucks.

Grey iris and irregular pupil from Marek's disease Source: United States Department of Agriculture


Leg paresis (partial paralysis) from Marek's disease Source: The Merck Veterinary Manual


Skin lesions from Marek's disease Source: The Merck Veterinary Manual


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http://poultryone.com/articles/mareksdisease.html
MAREKS DISEASE (MD), is a common virus that causes internal lesions (tumors), and kills more birds than any other disease. It is so common that you should assume you have it in your flock, even if you detect no evidence.

Mareks is a member of the herpesvirus family of viruses. It is also known as 'Range Paralysis'. Mareks is spread through airborne feather dander so microscopic that it can spread from one farm to another via the wind, even when no human or bird contact is made between the two farms. The virus enters through the bird's respiratory tract.

The turkey version is Herpes Virus Turkey (HVT), and the waterfowl version is known as Duck Virus Enteritis (or DVE). All three are from the same family of viruses.

It's not common for MD, HVT, and DVE to cross over between chickens, turkeys, and ducks kept together, but it has happened.

The study of Mareks Disease in poultry is exciting because it has had a profound effect on cancer research in all species, including human. And the Mareks vaccine for chickens was the first time medical science was able to produce an effective cancer vaccine for any species.

There are a few different types of Mareks in chickens. The most common are eye, visceral (tumor producing), and nerve.

The nerve version is known by some Fanciers as 'down in the leg', and symptoms range from slight to severe paralysis in the wings, legs, or neck, and usually results in death from trampling by other chickens, and/or the inability to get to food and water. There can be 'transient' paralysis that disappears after a few days, such as a dropped wing that suddenly corrects itself. In the eye version, you'll detect an irregularly shaped pupil, cloudy eye ('gray eye'), or sensitivity to light. It can result in blindness. The visceral version should be considered when a bird is just generally 'wasting'.

Mareks is extremely contagious but does not spread vertically (to the egg). Youngsters should develop a natural immunity (called 'age resistance'), by the time they're five months old. This is one of the reasons it is important to raise your youngsters separately from your oldsters. The older birds that have encountered Mareks and have managed to survive are carriers. New birds coming in from other flocks are always potential carriers.

Mareks usually hits between 5 and 25 weeks of age, but can appear even later if the bird had 'latent' MD and is substantially stressed. However, if the bird is a few years old, I would suspect a similar disease called Lymphoid Leukosis (which does pass to the egg). Both diseases will produce internal lesions (or tumors), detectable upon post mortem examination, but LL does not produce paralysis.

Since it is so difficult to control your birds' exposure to Mareks, (showing, bringing in new birds, airborne spread from other farms), the best course is prevention. That starts with completely sanitizing your brooders. Then consider the Mareks vaccine, which is available in a freeze-dried form through a few of the mail-order suppliers, and is easy to administer to day-old chicks. The downside is that you have to administer the vaccine within one-half hour of mixing it with the fluid it comes with (diluent), and you have to plan your hatching to accommodate the 'all-or-none' vaccination within a day or two of hatch. (After one hour of mixing the Mareks vaccine, the active virus dies and the vaccine becomes ineffective.)

You'll inject the vaccine under the skin at the back of the neck (subtecaneously). Be careful though, you could stick right through to the other side and vaccinate the floor instead of the chick!

There are certain 'B factors' contained in the blood of some chickens that make them resistant to Mareks. If you have access to a lab for 'B type' blood testing, 'B factor' birds are desirable for breeding for a 'Mareks-free' flock.

Overall, the easiest way by keep Mareks out of your flock (but not the most effective), is to promote 'age resistance' by keeping your youngsters separate from the adults and away from the poultry shows until they're over 5 months old.

How to vaccinate: http://poultryone.com/articles/mareks.html

MAREKS DISEASE
By: Peter J. Brown, First State Veterinary Supply, Inc.

Actually they are one in the same. Range Paralysis is an older term that was used before it was understood exactly what caused this disease. Birds that were ranged on open range and became lame were said to have Range Paralysis. Today the modern term for this disease is Mareks Disease. Mareks,was first described in 1907 by Dr. Marek who was a Hungarian researcher. Thus the name Mareks disease. So,just what is Mareks Disease ? It is a highly contaigous Avian Herpes Virus that is highly Cell Associated. This means that the Virus must be inside a Cell of the bird in order to spread. Mareks Disease must be differentiated between Avian Leukosis Complex,which is made up of three separate diseases. Those Diseases are,Mareks Disease,Lymphoid Leukosis and Reticuloendotheliosis Virus. The last two diseases are caused by Retroviruses and Reticuloendotheliosis Virus is rare in Poultry. What Mareks Disease really boils down to is Chicken Cancer. It is a virus that causes skin lesions as well as lesions of the Visceral ( gut ) organs. It is a Tumor forming Virus.
How does Mareks Disease spread ? The mechanism by which Mareks Disease spreads from bird to bird is quite complicated. So,I will tell you that it spreads through the infected birds feather follicles and is in the dander that comes from the birds feathers. The spread to other tissues in the birds body can onlty take place through the blood stream. The virus must infect white blood cells and travel about inside them in order to infect other tissues. The Mareks Disease virus is related to the Epstein-Barr virus that causes Hodgkins disease in humans. However the Mareks Disease virus poses no threat as it is incapable of growing in mammalian cells.

So what organs are affected by the Mareks Virus ? Generally the virus will attack the nervous systemas well as other body organs such as the eye. You may see a crippiling of the birds or a discoloration of the iris in the eye. The virulence ( strength ) of the particular virus affecting your birds will usually determine the severity of the disease. The discoloration in the iris of the eye has led to the term Gray Eye. You may only see a reddening of the tissue around the feather follicle,this tissue may be raised around the base of the feather shaft and is generally called skin Leukosis but it is actually caused by Mareks Disease. The spread of the virus to the periphial nerves usually results in the enlargement of the nerves which will eventually lead to paralysis of the affected limb or organ. The spread of the virus to the birds eye may result in blindness as well as depigmentation of the iris of the eye.

Can older birds be vaccinated for Mareks Disease ? The answer to this question is ,yes. The age of the bird really does not matter as long as the bird has not been exposed to the Mareks Virus prior to vaccination. If a bird that has not been vaccinated for Mareks Disease comes down with the obvious symptoms of Mareks it may be of value to vaccinate anyway. There is some research to show that some birds may recover after vaccination. This would possibly work on birds whether or not they were vaccinated before. Some research has suggested that re-vaccination 4 to 6 weeks after the initial vaccination was of value in preventing new cases of Mareks disease in high risk areas. It is important to keep in mind that birds that have been infected are shedding this virus at a very heavy rate from their follicles and it would be of value to keep feathers about your coop cleaned up. Regular spraying with oxine will go a long way in keeping this disease as well as other diseases under control. Concerning the use of bleach as a disinfectant: go ahead and use it if you so desire but be aware that to my knowledge there are no studies to show the effectiveness of bleach against any disease organism. Oxine has reams of test data against a wide range of Pathogens and is designed to be used specifically for disinfection purposes. Consider this: during the anthrax scare of a few years ago, The Hart Senate Office Building in Washington,D.C. was heavily contaminated with Anthrax. The disinfectant of choice (although it was used in its Gaseous Form) was Oxine. I don’t recall them using bleach as an alternative. Remember that you get what you pay for . My Dad once told me that if you want good clean quality Oats that they come at a price,and that if you want the Oats after they come through the horse they come a bit cheaper. Nuf said.

I thought it would be of value to walk you through the Mareks Disease infection from start to finish from the birds perspective. This way you might get a better understanding of just what is going on during an active outbreak of the disease. Infection usually takes place as the birds inhale the Mareks Virus and it sets up shop in the respiratory system. Witnin five days the Mareks Virus will invade White blood Cells in the Respiratory System and be carried to the Spleen,Bursa and the Thymus. The Virus likes to grow in White Blood Cells and starts growing in B-cells and starts to infect and kill off B-cells in the Spleen,Bursa and the Thymus. The Mareks virus is now killing so many B-cells that the Immune System begins to react to the Virus Infection. Many T-cells are generated by the Immune response. These activated T-cells can be susceptible to a latent infection by the Mareks Virus. These infected T-cells may eventually become active Mareks Disease Tumor Cells. The Immune System mounts a measurable Antibody response but a temporary Immune Suppression also occurs as well. Keep in mind that all of this is taking place in a very short period of time. Usually within one weeks time. The Virus now spreads throughout the blood stream through the infected White Blood Cells. The Mareks Virus will spread to various other organs at this time as well as the feather follicle epithelial ( surface ) cells where the Virus will divide and form cell free extremely infectious Virus Particles. The birds then shed the Virus from their bodies in the form of dander. This dander is highly infective and when susceptible birds breathe in the Virus particles contained in the dander,infection will take place as earlier described. Within two weeks post infection a permanent Immune Suppression takes place that affects both the B-cells and the T-cells. Approximately five weeks after infection takes place the Mareks Virus has sufficiently infiltrated vital organs and nerves that paralysis soon occurs. Birds may become listless and show a paralysis of one wing or drag a leg behind them. Some birds may only show a weakness of the legs or both wings. Starting at about six weeks post infection birds will start to form Tumors due to the infected T-cells starting to multiply and are now transformed into Cancer Cells. They are also responsible for Atherosclerosis or Hardening of the Arteries. Tumors may affect any of the organs of the body and the degree of Tumor formation will depend upon the Virulence (strength) of the infecting Virus.

Vaccinating for Mareks with the Mareks vaccine : Vaccination should take place as close to one day of age if at all possible,but may be done at any age as earlier discussed. Mareks vaccine is unique in that it does not stop a bird from becoming infected with the virus,but it stops the formation of the Tumors that are caused by the Mareks virus. Birds that are newly vaccinated should not be exposed to adult birds for at least fourteen days to allow the vaccine to take hold. The vaccine comes as a two part vaccine. One bottle contains a small freeze dried wafer which is the actual vaccine. This is a Live Virus vaccine and can not be saved once it is mixed. Once mixed the life of the vaccine is approximately two to two and one half hours. The second part of the vaccine is a bottle of diluent which is 200 cc/ml of extender. It is not just water but a broth so to speak of special growth media for the Vaccine Virus to survive on during mixing and vaccination. I would suggest to you that you split the vaccine into four equal parts so that you may get four uses out of one bottle of vaccine. Cut the small vaccine wafer into quarters as best as you can.Use care not to contaminate the Mareks Diluent. Never actually open the bottle but use a clean needle and work through the rubber stopper and draw what you need from that. Always check the Diluent bottle for contamination before using: cloudiness or something growing in the bottle. If the Diluent is contaminated or you are unsure discard the bottle and get a fresh bottle of Diluent before proceeding. Take the large Diluent bottle and transfer 50 cc/ml into a clean baby food jar or similar glass bottle. This bottle must be glass. Now take the 1/4 vaccine wafer and mix with the 50 cc/ml of Diluent in the baby food jar and you are ready to vaccinate. Remember to immediately put the remaining Diluent and the small bottle of Vaccine back in the refrigerator. You are now ready to administer the Vaccine. The dose is .2 cc 2/10 cc under the skin of the neck of each bird.Remember to keep track of time so that you don’t use Vaccine that is to old. Putting the mixed vaccine bottle in an ice bath will have some value in preserving the life of the mixed vaccine.

MIXED VACCINE CAN NOT BE SAVED UNDER ANY CIRCUMSTANCES EVEN IF YOU FREEZE IT.


If you have any question about this article or any other health issue, please feel free to contact Peter Brown at 1-800-950-8387.
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WOW!! What a great collection of info Kathyinmo! Thank you.