Fowl Typhoid & Cholera in Poultry: Symptoms & Control

Fowl Typhoid

Fowl typhoid is a bacterial disease that can affect birds of any age, primarily chickens and turkeys. It shares many similarities with pullorum disease, but it typically affects adult or mature chickens, while other bird species show relative resistance. In this article, we will explore the causes, transmission, clinical signs, diagnosis, prevention, and treatment of fowl typhoid.

Causes of Fowl Typhoid:

Fowl typhoid is caused by gram-negative bacteria, specifically Salmonella gallinarum and S. pullorum.

Transmission of the Disease:

The disease can be transmitted orally through contaminated food, water, or cannibalism, as well as through the respiratory tract. Other modes of transmission include wounds and contact with infected carcasses.

Fowl typhoid is more frequently transmitted between adult birds compared to pullorum disease. Additionally, it can be spread between houses by rats, wild birds, and human traffic carrying dead birds and droppings.

Epidemiology:

Fowl typhoid typically affects chickens older than 12 weeks, and reported losses can range from 40-50%. To minimize the risk, it is advisable to obtain birds or hatching eggs from hatcheries participating in the National Poultry Improvement Plan (NPIP).

Clinical Signs:

The following clinical signs may indicate the presence of fowl typhoid:

1. Higher mortality in adult birds is characterized by sudden or sporadic deaths.
2. Decreased egg production and anorexia.
3. Weakness and birds standing with one leg, often accompanied by isolation and sulfur-colored diarrhea.
4. Young chickens and poultry may be affected, especially if breeders lay infected eggs.
5. The pale, anemic appearance of combs and wattles.
6. Increased thirst and dehydration.
7. Greenish-yellow diarrhea.
8. Loss of appetite and reduced feed consumption.

Postmortem Examination:

Postmortem examination may reveal the following lesions:

1. Chicks and poults show similar lesions to pullorum disease, such as caecal plugs (yellow cores in the caecum) and swollen hock and wing joints.
2. Adults may exhibit a bronze-colored (bile-stained) liver with occasional necrotic foci, enlarged spleen and liver, and enteritis.

Diagnosis:

Bacterial culture is the definitive method for diagnosing fowl typhoid. Additionally, whole blood plate agglutination can be used to test for reactors of both Salmonella pullorum and Salmonella gallinarum.

Prevention, Control, and Treatment:

To prevent and control fowl typhoid, the following measures should be implemented:

1. Ensure that eggs used for hatching are from healthy parent flocks to avoid transmission through eggs.
2. Maintain strict sanitation practices on the farm.
3. Provide clean feed and water to the birds.
4. Properly dispose of dead birds.
5. After an outbreak, thoroughly clean and disinfect the premises.
6. Treatment with drugs like Sulphonamides, tetracyclines, furazolidone, and furaltadone can be used, but it is important to note that treatment is a salvage operation and does not prevent birds from becoming carriers. Infected carriers should be eliminated from the farm.
7. Vaccination for fowl typhoid in commercial layers can be done at 2 months of age via intramuscular injection in the breast muscle. However, this is not performed in breeders during eradication programs. Serologic monitoring of breeder flocks is necessary, and blood testing and reactors should be culled. It is important to note that the immunity/protection conferred by vaccination is short-lived, lasting approximately 6 months.

Fowl Cholera (Pasteurellosis, Hemorrhagic Septicemia) of Fowls

Fowl cholera is another infectious disease that affects various types of birds, characterized by acute septicemia leading to sudden death and high mortality. It is caused by the bacterium Pasteurella multocida. Unlike fowl typhoid, it primarily affects adult or mature birds rather than young ones.

There are three forms of fowl cholera: acute, chronic, and the parachute form. In outbreaks, the disease can cause significant mortality within a week and then disappear.

Causes of Fowl Cholera:

Fowl cholera is caused by Pasteurella multocida, a Gram-negative rod bacterium. It has several pathogenic serotypes, including 1, 3, and 4. It is susceptible to drying and can be eliminated with proper disinfectants.

Transmission of the Disease:

The disease can be transmitted through ingestion, mechanically by arthropod vectors, or by inhalation. Cats and rodents can carry the infection as vectors. Infected birds shed the bacteria in their oculonasal secretions and feces, contaminating feed and water.

Older birds can act as carriers without showing clinical signs, thus serving as a constant source of infection. The bacterium can also persist in infected carcasses and be transmitted through cannibalism. Contaminated crates and equipment can also contribute to the spread of infection. However, there have been no reports of egg transmission.

Clinical Signs:

The clinical signs of fowl cholera vary depending on the form of the disease:

Parachute Form: This form does not display outward signs. Birds may fall from their roosts, collapse while feeding, or die suddenly, often leading flock owners to mistake it for poisoning and neglect necessary measures for disease containment.

Acute Form: Birds affected by the acute form may exhibit gasping or choking sounds while breathing. They may also experience yellowish or greenish-yellow diarrhea, though some birds may die before these symptoms appear. The combs and wattles may initially become red and later swollen and purple.

Other signs include fever, excessive thirst, extreme drowsiness, foul-smelling nasal discharge, and sudden death. Laying birds may be found dead in their nests, with reduced feed consumption and decreased egg production.

Chronic Form: This form typically follows an acute attack and is characterized by depression, conjunctivitis, dyspnea, and swollen wattles. Birds may also experience weight loss and develop joint swelling accompanied by stiffness. Eventually, these swellings may rupture and discharge a creamy or cheesy mass. Birds that die from this form of the disease often exhibit hemorrhages in their tissues and internal organs.

Postmortem Examination:

Postmortem lesions in fowl cholera include internal laying and egg yolk peritonitis. Hemorrhages and congestion may be observed in the liver, spleen, and kidney, along with hypertrophy of the lungs. Positive diagnosis usually requires a microscopic examination of the blood.

Diagnosis:

The diagnosis of fowl cholera involves isolating and identifying the bacterium through bacterial culture.

Differential Diagnosis:

To differentiate fowl cholera from other diseases, the following conditions should be considered:

1. Fowl Typhoid: Fowl typhoid lacks the swelling of wattles and combs observed in fowl cholera.
2. Colibacillosis: All eyes decrease in size in cases of colibacillosis.

Treatment and Prevention:

The following measures can be taken for the treatment and prevention of fowl cholera:

1. Treatment: Tetracyclines and Sulphaquinoxaline can be administered through drinking water for seven days to control the disease.
2. Prevention: Purchase clean birds from reliable sources to minimize the risk of introducing the infection.
3. During an outbreak, it is important to cull any breeder birds exhibiting swollen wattles or joints.
4. Thorough cleaning and disinfection of the premises should be carried out after an outbreak to break the fowl cholera cycle in the house.
5. Rodent control measures should be implemented, and efforts should be made to keep cats out of the poultry house.
6. Vaccination can be an effective preventive measure against fowl cholera. It is recommended to use a vaccine containing a serotype of Pasteurella that has been isolated from the specific house in the past, as this ensures a targeted response. However, it's important to note that vaccination alone may not provide long-term protection, and it should be combined with proper biosecurity measures and disease management practices.
7. In addition to specific treatment and prevention measures, providing birds with a balanced diet that includes essential vitamins and minerals can help speed up the recovery process and strengthen their immune system.

Conclusion

Fowl typhoid and fowl cholera are two bacterial diseases that pose significant threats to poultry. Understanding their causes, modes of transmission, clinical signs, and appropriate diagnostic and preventive measures is crucial for effective disease management.

By implementing strict biosecurity measures, practicing proper sanitation, sourcing healthy birds, and using vaccination where appropriate, poultry farmers can minimize the impact of these diseases and safeguard the health and productivity of their flocks. Regular monitoring, prompt diagnosis, and early intervention are key to preventing and controlling the spread of fowl typhoid and fowl cholera.