Major Poultry diseases symptoms Prevention and treatments

14 Major Chicken Diseases: Symptoms, Prevention, and Treatment

Newcastle Disease (ND) is a one of the most highly contagious viral disease that affects a wide range of bird species, including domestic poultry. It is caused by the Newcastle Disease Virus (NDV), a member of the paramyxovirus family. ND is a significant threat to poultry farming due to its potential for causing high mortality and economic losses.

1.)Newcastle Disease

Image of a bird affected by New castle disease

NOTE:There is no specific treatment for Newcastle Disease.Diagnosis typically involves Observing symptoms like respiratory distress or twisted necks.

Symptoms of Newcastle Disease

Symptoms vary depending on the strain of the virus (lentogenic, mesogenic, or velogenic), the age of the bird, and its immune status. They generally fall into respiratory, gastrointestinal, and nervous system categories:

1. Respiratory Symptoms of New Castle disease
   • Coughing
   • Sneezing
   • Nasal discharge
   • Labored breathing
2. Digestive Symptoms of New Castle disease
4. 
5. • Greenish, watery diarrhea
   • Loss of appetite
   • Weight loss
6. Neurological Symptoms of New Castle disease
   • Twisted neck (torticollis)
   • Paralysis of wings and legs
   • Tremors
   • Circling or inability to stand
7. Other Symptoms of New Castle disease
   • Sudden drop in egg production
   • Thin-shelled or misshapen eggs
   • Depression and lethargy
   • High mortality rates, especially with velogenic strains

Transmission of New Castle disease

Newcastle disease  is transmitted through:

• Direct contact with infected birds, their droppings, or respiratory secretions.
• Contaminated feed, water, equipment, or clothing.
• Wild birds, rodents, and other animals can also act as carriers

Prevention and Control of New Castle disease

Image of chicks drinking aloe vera water to prevent New castle disease

1. Vaccination:
   • Live Vaccines: Lentogenic strains (e.g., LaSota or B1) are commonly used for broilers.
   • Inactivated Vaccines: Administered to layers and breeders for longer immunity.
   • Timing: Chicks are typically vaccinated at 7–14 days, with boosters as needed.
2. Biosecurity:
   • Isolate new birds before introducing them to the flock.
   • Restrict access to poultry houses.
   • Disinfect equipment and facilities regularly.
3. Good Husbandry:
   • Provide balanced nutrition and clean water to boost immunity.
   • Minimize stress factors like overcrowding.

1.1)Infectious coryza

Infectious coryza is a highly contagious bacterial disease affecting chickens, caused by Avibacterium paragallinarum. It primarily affects the respiratory system and leads to significant economic losses in poultry farming due to reduced productivity.

Image of Infectious coryza affecting chick

Signs and Symptoms of Infectious coryza

1. Respiratory Issues:
   • Swollen sinuses.
   • Nasal discharge.
   • Sneezing and coughing.
2. Behavioral Changes:
   • Reduced activity.
   • Decreased appetite and water intake.
   • Isolation from the flock.
3. Physical Indicators:
   • Swollen face or wattles.
   • Foul-smelling discharge from nostrils.
   • Conjunctivitis (inflammation of the eyes).
4. Egg Production:
   • Decline in egg production or production of deformed eggs.

Transmission of Infectious coryza

• Spread occurs through direct contact with infected birds or contaminated feed, water, and equipment.
• Birds that recover can become carriers, shedding the bacteria intermittently.

Diagnosis of Infectious coryza

• Diagnosis is confirmed through clinical signs, bacterial cultures, and laboratory testing of samples from nasal discharges or affected tissues.

Treatment of Infectious coryza

1. Antibiotics:
   • Commonly used antibiotics include sulfonamides, erythromycin, and oxytetracycline.
   • Note: Antibiotic resistance is a growing concern; veterinary guidance is essential.
2. Supportive Care:
   • Ensure access to clean water and a balanced diet to aid recovery.
   • Isolate affected birds to limit spread.

Prevention and Control of Infectious coryza

1. Vaccination:
   • Vaccines against infectious coryza are available and effective in reducing outbreaks.
2. Biosecurity Measures:
   • Maintain strict hygiene in the poultry house.
   • Quarantine new birds before introducing them to the flock.
   • Clean and disinfect equipment regularly.
3. Environmental Management:
   • Ensure proper ventilation in poultry houses.
   • Avoid overcrowding, as stress can predispose birds to infection.

2.)Infectious Bursal Disease (Gumboro)

Chickens between 3 and 6 weeks old are most susceptible.

Infectious Bursal Disease (IBD), also known as Gumboro disease, is a highly contagious viral disease that primarily affects young chickens, targeting their immune system. It is caused by the infectious bursal disease virus (IBDV), a member of the Birnaviridae family. The disease is named after the bursa of Fabricius, an immune organ in birds that the virus attacks, leading to immunosuppression.

Symptoms of Infectious Bursal Disease (Gumboro)

• Depression and lethargy
• Ruffled feathers and reluctance to move
• Diarrhea (often whitish or watery)
• Dehydration
• Swollen or hemorrhagic bursa of Fabricius (seen on necropsy)
• Sudden death in severe cases

Transmission of Infectious Bursal Disease (Gumboro)

• Primary Source: Contaminated feed, water, or litter.
• Virus Shedding: Infected birds excrete the virus in their droppings, contaminating the environment.
• Environmental Stability: The virus is highly resistant to environmental conditions and disinfectants, allowing it to persist in poultry houses for long periods

Diagnosis of Infectious Bursal Disease (Gumboro)

• Clinical Signs: Sudden onset of symptoms in susceptible age groups.
• Necropsy Findings: Enlarged, hemorrhagic, or atrophied bursa of Fabricius.
• Laboratory Tests: Virus isolation, PCR, or serological tests to confirm the presence of IBDV.

Prevention and Control of Infectious Bursal Disease (Gumboro)

1. Vaccination:
   • Vaccines are the primary tool for preventing IBD.
   • Broiler chicks are usually vaccinated around 14–21 days of age.
   • Breeder hens are vaccinated to pass maternal antibodies to their offspring.
2. Biosecurity:
   • Clean and disinfect poultry houses between flocks.
   • Minimize contact with outside birds or contaminated equipment.
   • Maintain proper litter management to reduce viral loads.
3. Management Practices:
   • Provide good nutrition to support immune function.
   • Reduce stressors like overcrowding and temperature fluctuations.

Treatment

• There is no specific treatment for IBD.
• Supportive care, such as providing electrolytes and vitamins, can help reduce mortality and aid recovery in mild outbreaks.

3.)Marek’s Disease

Marek’s disease is a highly contagious viral disease that affects chickens. It is caused by a type of herpesvirus called Marek’s disease virus (MDV). This disease primarily targets the nervous system and immune cells, causing a range of symptoms that vary depending on the form of the disease. It is a major concern in poultry farming due to its potential to cause significant economic losses.

Forms of Marek’s Disease

1. Neurological (Classical) Form:
   • Characterized by paralysis of the legs, wings, or neck.
   • Chickens may appear uncoordinated or have difficulty standing or walking.
2. Ocular Form:
   • Causes changes in the eyes, including irregularly shaped pupils or a loss of eye pigment (grey eye).
   • Can lead to blindness.
3. Cutaneous Form:
   • White or raised lesions appear on the skin, particularly around feather follicles.
4. Visceral Form:
   • Tumors develop in internal organs such as the liver, spleen, kidneys, or gonads.
   • This form is often associated with sudden death.

Transmission of Marek’s Disease

• The virus is spread through infected chicken dander and dust. It can survive in the environment for long periods.
• Birds become infected by inhaling virus particles.

Symptoms of Marek’s Disease

• Paralysis or difficulty walking
• Weight loss
• Depression and lethargy
• Decreased egg production
• Enlarged nerves (visible in severe cases)

Prevention of Marek’s Disease

1. Vaccination:
   • Vaccination is the most effective method of prevention.
   • Chicks are typically vaccinated on their first day of life or in ovo (before hatching).
   • Vaccines do not prevent infection but help reduce the severity of the disease.
2. Biosecurity Measures:
   • Maintain a clean environment to minimize virus spread.
   • Isolate new birds before introducing them to a flock.
   • Limit visitor access and sanitize equipment regularly.
3. Genetic Resistance:
   • Some chicken breeds show natural resistance to Marek’s disease. Selective breeding can help reduce susceptibility.

4.)Fowl Cholera

• Symptoms: Swollen wattles, greenish diarrhea, loss of appetite, respiratory issues.
• Prevention: Vaccination and good hygiene.
• Treatment: Antibiotics like sulfa drugs or tetracyclines.

5.) Avian Influenza (Bird Flu)

• Symptoms: Coughing, sneezing, swollen head, purple discoloration of wattles.
• Prevention: Isolate flocks, practice biosecurity.
• Treatment: No specific treatment; report outbreaks to authorities.

6.)Coccidiosis

Coccidiosis is a parasitic disease caused by protozoa of the genus Eimeria. It primarily affects the intestinal tract of poultry, especially chickens, and can lead to significant economic losses in the poultry industry due to reduced growth rates, decreased egg production, and high mortality in severe cases. The disease is particularly prevalent in intensive farming systems where birds are housed in crowded and humid conditions.

Image of coccidiosis affecting chicken

Transmission of Coccidiosis

Through ingestion of sporulated oocysts found in contaminated litter, feed, or water.

Lifecycle of Eimeria

1. Oocysts Excretion: Infected birds shed unsporulated oocysts in their feces.
2. Sporulation: Oocysts sporulate in the environment under warm and humid conditions, becoming infectious.
3. Infection: Birds ingest the sporulated oocysts.
4. Replication: Inside the host, the parasite multiplies in the intestinal cells, causing damage and clinical signs.

Symptoms of Coccidiosis

The severity depends on the Eimeria species, parasite load, and the bird’s age and immunity. Common symptoms include:

• Diarrhea, often bloody or watery (especially with E. tenella).
• Weight loss and reduced feed intake.
• Dehydration.
• Lethargy and ruffled feathers.
• Poor growth and reduced egg production.
• High mortality in severe cases.

Diagnosis  of Coccidiosis

• Clinical Signs: Sudden onset of diarrhea, weakness, and other symptoms in a flock.
• Postmortem Examination:
  • Lesions in the intestines, which vary by the Eimeria species.
  • Presence of oocysts in intestinal scrapings under a microscope.
• Laboratory Tests: Fecal examination, PCR, or histopathology for confirmation.

Prevention and Control of Coccidiosis

1. Vaccination:
   • Live attenuated vaccines can be used to develop immunity in young birds.
   • Often administered to breeders and layers.
2. Coccidiostats and Coccidiocides:
   • Added to feed or water to prevent or control outbreaks.
   • Common drugs include ionophores (e.g., monensin, salinomycin) and synthetic chemicals (e.g., amprolium, toltrazuril).
   • Rotation of drugs is essential to avoid resistance.
3. Biosecurity and Management:
   • Keep litter dry and clean to reduce oocyst sporulation.
   • Minimize overcrowding to reduce stress and exposure.
   • Implement proper cleaning and disinfection between flocks.
4. Probiotics and Feed Additives:
   • Supplementing feed with probiotics or prebiotics can help improve gut health and resilience to infections.

Treatment of Coccidiosis

• In case of an outbreak, anticoccidial drugs are administered in feed or water to treat infected birds like Amprolium,Coccidiosis ESB3 30%
• Supportive care (e.g., electrolytes and vitamins) helps reduce stress and mortality.

7.)Infectious Bronchitis

• Symptoms: Coughing, sneezing, reduced egg production, watery albumen in eggs.
• Prevention: Vaccination and isolating sick birds.
• Treatment: Antibiotics for secondary infections.

7.1)lymphoid leukosis disease

Lymphoid Leukosis (LL) is a disease in chickens caused by a group of retroviruses collectively known as avian leukosis virus (ALV). It primarily affects the lymphoid tissue, particularly the B cells, and can result in the formation of tumors, especially in the liver, spleen, and bursa of Fabricius. LL is a significant concern in poultry production because it can cause economic losses through decreased egg production, poor growth rates, and increased mortality.Lymphoid Leukosis spreads vertically (from hen to egg) or horizontally (from bird to bird through direct contact, contaminated environments, or fomites).

Symptoms of lymphoid leukosis disease

• Chronic wasting or poor growth
• Reduced egg production in layers
• Enlargement of the liver, spleen, or bursa of Fabricius
• Tumors in visceral organs such as the liver or spleen
• Lethargy, pale combs, and decreased feed intake

Diagnosis of lymphoid leukosis disease

• Clinical signs and necropsy findings, including the presence of tumors in internal organs.
• Histopathological examination of affected tissues.
• Polymerase Chain Reaction (PCR) or Enzyme-linked Immunosorbent Assay (ELISA) for viral detection.

Prevention of lymphoid leukosis disease

1. Biosecurity Measures:
   • Maintain strict hygiene and sanitation in poultry houses.
   • Avoid the introduction of infected birds into flocks.
2. Genetic Resistance:
   • Select and breed chickens with genetic resistance to ALV.
3. Vertical Transmission Control:
   • Screen breeder hens for ALV and remove infected birds to prevent egg transmission.
4. Vaccination:
   • No commercial vaccines are widely available for ALV; hence prevention focuses on management and breeding practices.

8.)Fowl Pox

Fowl Pox is a slow-spreading viral disease affecting chickens, turkeys, and other avian species. It is caused by the Avipoxvirus, part of the Poxviridae family. The disease occurs in two forms: dry (cutaneous) and wet (diphtheritic) forms, both of which can significantly impact poultry productivity.

Image of fowl pox affecting chicken

Symptoms of Fowl Pox

• Reduced feed intake and weight loss.
• Drop in egg production in layers.
• Lesions or scabs on combs, wattles, eyelids, or legs (dry form).

• Difficulty breathing or swallowing (wet form).
• Depression and lethargy.

Transmission of Fowl pox

• Spread through direct contact with infected birds or contaminated surfaces.
• Vectors such as mosquitoes and other blood-sucking insects play a significant role in transmission.
• The virus can survive in the environment for long periods, particularly in scabs or lesions.

Prevention and Control of Fowl pox

1. Vaccination:
   • Administered as a live vaccine using a wing-web stab method.
   • Typically given to chicks at 6–10 weeks of age.
   • Booster vaccinations may be needed in high-risk areas.
2. Mosquito Control:
   • Eliminate standing water to reduce mosquito breeding.
   • Use insect repellents and screens in poultry houses.
3. Biosecurity:
   • Isolate new birds for at least two weeks.
   • Regularly clean and disinfect equipment and housing.

Treatment of Fowl Pox

• Providing a balanced diet and clean water.
• Treating secondary infections with antibiotics.
• Applying antiseptics to lesions in the dry form

9.)Pullorum Disease

• Symptoms: White diarrhea, ruffled feathers, high chick mortality.
• Prevention: Test breeding stock and cull carriers.
• Treatment: Antibiotics like sulfa drugs.