Newcastle disease

Newcastle disease (ND) is a highly contagious and often severe viral disease that affects birds, including domestic poultry. It is caused by a virus in the family of paramyxoviruses.

• The disease can cause respiratory, nervous, and digestive problems in affected birds [1].
• Newcastle disease virus (NDV) is an RNA virus and the most important of the 22 known APMV serotypes as a pathogen for poultry [2].
• The original classification of NDV isolates into one of three pathotype groups based on their pathogenicity in chickens as virulent (velogenic), moderately virulent (mesogenic), or of low virulence (lentogenic) has been used [3].

Newcastle disease can be fatal to birds, and it is considered a significant threat to poultry health worldwide. The virus can spread quickly through direct contact with infected birds, contaminated feed or water, or through the air.

• Newcastle disease is a highly contagious viral disease that causes respiratory and neurological signs in various avian species [11].
• It may cause acute death [11].

The severity of the disease can vary depending on the strain of the virus and the age and health status of the affected birds.

Newcastle disease is a viral infection that affects birds, causing a range of symptoms depending on the severity of the infection.

Respiratory Symptoms

• Coughing and sneezing
• Rattling breathing
• Increased respiration rate
• Diarrhea (greenish, watery)

These respiratory symptoms are often the first signs of Newcastle disease in birds. The virus can cause inflammation in the lungs and airways, leading to these characteristic symptoms.

Nervous Symptoms

• Muscle tremors
• Drooping wings
• Twisted head or neck
• Paralysis or sudden death (in severe cases)

In some cases, Newcastle disease can affect the nervous system of birds, causing a range of neurological symptoms. These can include muscle tremors, drooping wings, and even paralysis or sudden death.

Other Symptoms

• Sneezing or coughing
• Discharge from eyes or beak
• Decreased food and water intake
• Decreased egg production
• Swelling of the skin around the eyes and in the face

In addition to respiratory and nervous symptoms, Newcastle disease can also cause a range of other symptoms in birds. These can include sneezing or coughing, discharge from the eyes or beak, decreased food and water intake, and even swelling of the skin around the eyes and face.

Severity of Symptoms

The severity of symptoms can vary depending on factors such as the strain of the virus, concurrent infections with other organisms, environmental stress, immune status, species of infected bird, and age of host. Young birds are particularly susceptible to severe symptoms.

References:

• [2] - Symptoms of Newcastle disease include loss of appetite, coughing, gasping, nasal discharge, watery eyes, bright green diarrhoea and nervous signs.
• [3] - Sneezing, gasping for air, nasal discharge, difficulty breathing; Greenish, watery diarrhea; Ruffled feathers; Lack of appetite; Decreased egg production.
• [4] - Clinical signs · sneezing · nasal discharge · coughing · greenish, watery diarrhoea · depression · muscular tremors · drooping wings · complete paralysis or sudden death.
• [5] - Signs and symptoms of Newcastle Disease. Respiratory symptoms: coughing and sneezing, rattling breathing. Increased respiration; Diarrhoea (greenish, watery).
• [8] - Clinical signs · respiratory signs – gasping, coughing, sneezing and rales · nervous signs – tremors, paralyzed wings and legs, twisted necks, circling, spasms,.
• [9] - Sneezing or coughing · Discharge from eyes or beak · Decreased food and water intake · Decreased egg production · Swelling of the skin around the eyes and in the face.

Newcastle disease can be diagnosed using various diagnostic tests, which are crucial for early detection and control of the disease.

• Isolation of APMV-1: The virus responsible for Newcastle disease (APMV-1) can be isolated from live or recently dead birds through tracheal and cloacal swabs. This is a reliable method for diagnosing the disease [7].
• ELISA Test: Enzyme-linked immunosorbent assay (ELISA) is used to detect antibodies against Newcastle disease virus in chickens. However, this test has some limitations, such as being specific only to chickens and not providing information on the virulence of the virus [6].
• Real-time RT-PCR: Real-time reverse transcription polymerase chain reaction (RT-PCR) is a highly sensitive and specific method for detecting viral RNA typical of virulent Newcastle disease virus. This test is considered the gold standard for confirming infection in birds with clinical signs of disease [4].
• PMV-1 Matrix PCR: Positive samples on the PMV-1 Matrix PCR will be tested for Virulent Newcastle Disease (vND) formerly known as Exotic Newcastle Disease (END). This test helps to differentiate between different strains of the virus [9].

It's worth noting that diagnostic tests may include detection of antibodies, isolation of the virus, and molecular testing. The choice of test depends on the specific circumstances and the resources available.

References: [4] Real-time RT-PCR is the test of choice to detect viral RNA typical of virulent NDV and confirm infection in birds with clinical signs of disease. [6] Detection of antibodies to Newcastle disease virus (NDV) by ELISA in chickens only. Collect serum from clotted blood in a non-additive tube (e.g. plain red top ... [7] by P Paramyxovirus — Diagnostic Tests​​ Newcastle disease can be diagnosed by isolating APMV-1 from live or recently dead birds. Tracheal and cloacal swabs are ... [9] Positive samples on the PMV-1 Matrix PCR will be tested for Virulent Newcastle Disease (vND) formerly known as Exotic Newcastle Disease (END).

Treatment Options for Newcastle Disease

Newcastle disease, caused by the Newcastle disease virus (NDV), has no specific treatment. However, antibiotics can be administered to prevent secondary bacterial infections ([6][7]). The focus is on controlling and preventing the spread of the disease through vaccination and good hygiene practices.

• Antibiotics: Antibiotics are used to control secondary bacterial infections that may arise due to Newcastle disease ([2][6]).
• Vaccination: Vaccination is a crucial measure in preventing the spread of Newcastle disease. It involves administering vaccines to birds, especially those in high-risk areas or with known exposure to the virus.
• Supportive Care: In cases where birds are infected, supportive care such as providing adequate nutrition and hydration may be necessary.

Emerging Research on Treatment

Recent studies have explored the potential use of certain drugs and compounds in treating Newcastle disease. These include:

• Nitazoxanide (NTZ): A study found that NTZ treatment showed significant reduction in NDV replication in chickens ([3][5]).
• Niclosamide: Another study demonstrated that a sublethal dose of niclosamide could drastically reduce NDV replication ([8]).
• Oncolytic Virotherapy: There has been research into using Newcastle disease virus as an oncolytic agent for cancer treatment, though this is still in its experimental stages and not approved for use against the disease itself.

Important Considerations

It's essential to note that these treatments are either not proven or not specifically targeted at Newcastle disease. The primary

Differential Diagnoses for Newcastle Disease

Newcastle disease (ND) is a viral disease that affects poultry, and its clinical presentation can be challenging to distinguish from other diseases. The following are some of the differential diagnoses for ND:

• Highly Pathogenic Avian Influenza (HPAI): HPAI is a severe form of avian influenza that can cause respiratory and neurological signs in birds, similar to ND.
• Infectious Bronchitis: This disease causes respiratory symptoms in chickens, which can be mistaken for ND.
• Infectious Laryngotracheitis: A viral disease that affects the larynx and trachea of chickens, causing respiratory distress and coughing.
• Diphtheritic Form of Fowl Cholera: A bacterial disease that causes respiratory symptoms in birds, which can be similar to ND.
• Fowl Pox: A viral disease that causes skin lesions and respiratory symptoms in birds.

These differential diagnoses are important to consider when diagnosing ND, as they require different diagnostic approaches and treatments. According to [5], the commonest differentials of ND include highly pathogenic avian influenza, infectious bronchitis, infectious laryngotracheitis, and diphtheritic form of fowl cholera.

Additionally, [8] mentions that differential diagnosis includes other illnesses showing respiratory signs together with high mortality, such as fowl cholera, HPAI, Fowl pox. It is essential to consider these differential diagnoses when diagnosing ND to ensure accurate identification and treatment of the disease.

References: [5] MB Bello · 2018 · Cited by 151 [8] Apr 20, 2020 [9]