Contents
What is it?
Fowlpox, also known as the fowlpox virus, is a slow-spreading viral infection that affects both domesticated and wild avian species, especially poultry such as chickens, turkeys, pheasants, ducks, and geese. It is a common concern for poultry farmers and is found worldwide in many regions where poultry and wild birds are present.
What causes it?
The fowlpox virus, a large DNA virus highly resistant to normal environmental conditions, causes this disease. It belongs to the genus Avipoxvirus in the family Poxviridae.
This virus is classified into at least three distinct strains or types: the fowl poxvirus (FPV), which affects chickens and turkeys; the pigeon poxvirus (PPV), found in pigeons; and the canary poxvirus (CPV), which infects various species of wild birds.
This virus is spread through mosquitoes, flies, and other insect bites. They are the primary carriers of the disease.
Types of fowlpox
There are two main forms of fowlpox: dry form and wet form.
| Type | Symptoms |
|---|---|
| Dry form | Scabby, wart-like lesions on the face, comb, wattles, legs, and around the beak or eyes. |
| Wet form | Lesions inside the mouth, throat, and respiratory system, leading to difficulty eating, drinking, and breathing. Lesions in the digestive tract. |
Dry form (Cutaneous form)
The dry form of fowlpox is the most common.
This form of infection involves the development of scabby lesions, particularly on the skin in areas such as the head, neck, comb, wattles, eyelids, legs, and even feet. The lesions are yellow initially and then become dark brown, dry, and small, resembling wart-like growths. These wart-like scabs, which last 2 to 4 weeks, carry the virus containing the poxvirus and are highly infectious.
The stages of development of dry form are the following:
- Stage 1: The incubation period lasts approximately 3 to 14 days. During this time, the virus is present in the body but does not yet cause visible signs of infection.
- Stage 2: This stage typically lasts between 4 and 7 days. It is during this time that the first signs of the disease appear. Small, round, yellowish lesions begin to form on the bird’s skin.
- Stage 3: This stage, also referred to as the maturation of lesions, occurs 2 to 4 weeks after exposure to the disease. The lesions darken, turning brown to black as they dry out.
- Stage 4: The final stage is recovery. After 4 weeks, the scabs begin to fall off, signaling the start of recovery. However, scabs on areas such as the comb and wattles may take longer to heal.
Wet form (Diphtheritic form)
The wet form affects the mucous membranes of the bird, particularly the respiratory tract, but it can also affect the digestive tract.
In the case of the respiratory tract, it involves the appearance of yellow canker lesions inside the mouth, throat, and airways. If the lesions appear in the mouth or throat, they cause difficulty swallowing, which leads to reduced feed intake due to pain. If the lesions appear deeper in the respiratory tract, such as in the airways, they can cause difficulty breathing and, if very severe, may be fatal due to airway obstruction.
Compared with the dry form, wet fowlpox is more aggressive and causes higher mortality.
The development of the wet form follows these stages:
- Stage 1: During the first two weeks, the virus incubates similarly to the dry form of fowlpox. However, in this case, there are noticeable signs of the bird or poultry being unwell. They appear lethargic, and their appetite decreases.
- Stage 2: After the first week of incubation, around day 7 or 8, the first yellow lesions appear. These lesions may develop in the mouth, throat, or airways.
- Stage 3: After two weeks, the lesions begin to grow larger, causing difficulties in swallowing. They can become so large that they block the bird’s airways, leading to complications and even death.
- Stage 4: The final stage is recovery. However, if left untreated, the disease often leads directly to death. If the poultry does manage to recover, the lesions will begin to heal. Recovery can take up to 2 to 4 weeks. If the infection persists, the lesions may obstruct the airways, causing the bird to suffocate.
How to Diagnose It
Fowlpox is usually diagnosed based on symptoms and clinical signs, but there are also laboratory tests that can confirm it and differentiate it from other diseases with similar symptoms.
A PCR test can be performed by taking a sample from one of the lesions or blood. The advantage of using a laboratory test is that it can identify the virus even in the early stages, and even in asymptomatic birds, helping to prevent it from spreading to others.
Steps to Take When Fowlpox Is Confirmed in Your Flock
Once fowlpox has been confirmed in your flock, it’s important to take specific steps to manage the disease and prevent its spread. Here’s what to do:
- You must immediately isolate the infected birds from the healthy ones. If you do not do this, the virus will continue to spread. Therefore, keep the infected birds in a separate area and do not place them with any other animals.
- The second step is to place any recently introduced birds or those in close contact with the infected ones in quarantine, as they may be carrying the virus even if they haven’t shown symptoms yet. Once you do that, monitor all of them for any signs of illness. You can also test each bird to ensure they do not have the virus.
- Clean and disinfect the environment where the infected birds were kept. Also, clean the equipment, water containers, feed containers, and other surfaces that came into contact with them.
- Educate everyone who has access to the flock on the best biosecurity practices. Inform them about which birds are in isolation, which ones are healthy, how to dispose of waste, and how to disinfect equipment to reduce the risk of spreading the infection. At the same time, limit visitor access
- Once you have done all of these, you need to go back and take care of the infected birds. By providing them supportive care, you can do the following to make them more comfortable: offer them good nutrition. A diet rich in protein can boost the immune system. Make sure they have clean water at all times. Speak with a veterinarian and administer medications to ease the pain or inflammation. If necessary, the vet may prescribe antibiotics as well.
- Try to keep an eye on the flock and monitor them. In this way, you can quickly notice any complications, such as respiratory distress, and treat them promptly.
- Ensure that their environment is calm and quiet. Stress can make the infected birds, as well as the healthy ones, get sicker because it reduces the immune response. So, the environment should be stress-free with proper ventilation.
- If you notice a case in which the infection is very severe, you may consider culling. A veterinarian can assist you by choosing the best course of action if culling is recommended
- When the birds are healthy again—meaning no symptoms and no scabs remain—you can reintroduce them to the healthy ones.
There is no specific antiviral treatment for fowlpox. Supportive care, such as providing a clean environment, managing secondary infections, and ensuring the birds are hydrated, is essential.
Birds that have survived fowlpox develop immunity and cannot contract the disease again from the same virus strain.
Preventing fowlpox in poultry
To prevent fowlpox in poultry, it’s essential to use a combination of vaccination, strict biosecurity measures, and effective management practices to limit exposure to the virus.
Vaccination
You can reduce the risk of this disease by vaccinating your poultry flock at 6 to 8 weeks of age. If fowlpox is common in your area, you can provide booster vaccinations to older birds.
Always consult with a veterinarian. Do not vaccinate birds that are already showing symptoms. Vaccination adds stress to a bird’s immune system, potentially worsening their condition.
Maintain a clean environment
By regularly cleaning the environment and all the equipment, you control the mosquito population and reduce the risk of disease spread.
Fowlpox in Different Species of Poultry
Knowing how fowlpox affects chickens, turkeys, ducks, and other birds is important for preventing and managing the disease effectively.
Chickens
Chickens are susceptible to both types of fowl pox. This disease impacts them during egg production, reducing egg yield. It can also lead to weight loss due to difficulty eating if they have the wet form, or a decrease in appetite with the dry form.
Turkeys
Turkey flocks are more commonly affected by the wet form of the disease. In some cases, the wet form can cause scabs and lesions on the head and feet of turkeys. The wet form leads to a higher mortality rate in turkeys due to their small trachea, which makes them vulnerable to airway obstruction.
