What is the Newcastle disease virus?
Newcastle disease virus (NDV), also known as Avian paramyxovirus 1 (APMV-1), is a virus belonging to the Paramyxovirus family (Paramyxoviridae) Paramyxovirus genus (Paramyxovirus). It can cause a highly contact, acute, and severe infectious disease called Newcastle disease (ND). This disease mainly affects poultry, especially chickens, but it can also infect other birds, such as beaded chickens, turkeys, pheasants, peacocks, etc. Ducks and geese have a certain resistance to this disease, while mammals usually have a strong resistance to the disease.
Structure of Newcastle disease virus
The genome of NDV is single-stranded negative RNA, and mature virus particles are spherical in shape, with a diameter of about 120-300 nm. The surface of the virus has radially arranged fibrous processes, and these structures are essential for it to infect host cells.
Symptoms of Newcastle disease in chickens
Newcastle disease exhibits a variety of clinical symptoms, including respiratory, nervous, and digestive system symptoms.
Respiratory symptoms
Dyspnea is manifested as coughing, sneezing, and breathing with mouth open.
Breathing is often accompanied by “grunting” or other abnormal sounds.
Digestive system symptoms
Discharge yellow-green thin stools, which may be accompanied by blood.
Appetite is reduced, and drinking water is increased.
Nervous system symptoms
Mental malaise, neck twisting, unsteady standing, muscle tremor,r, and other manifestations.
Some chickens may experience paralysis or paralysis.
The incubation period of the disease is usually 2 to 15 days, and it can spread rapidly after the onset of the disease, and the mortality rate can be as high as more than 90% in unvaccinated chickens.
Why is it called Newcastle disease?
The origin of the name Newcastle disease (ND) is related to the historical background in which the disease was first formally identified and named. In 1926, the disease was discovered almost simultaneously on the island of Java in Indonesia and Newcastle upon Tyne in the United Kingdom. However, it was not until 1927 that Doyle confirmed through scientific research that this was a new infectious disease different from the then-known chicken fever (that is, avian influenza), and in order to distinguish it from the latter, according to its discovery in the United Kingdom (Newcastle), the disease was named “Newcastle disease”.
Is Newcastle disease a zoonotic disease?
Newcastle Disease is not a typical zoonotic disease, but it can indeed infect humans. Newcastle disease is a highly contagious avian disease caused by the Newcastle disease virus (NDV), which mainly affects birds, especially poultry. Although the virus can cause serious health problems in birds and may cause a mortality rate of up to 100%, infections in humans are relatively rare and usually have mild symptoms.
The impact of Newcastle disease on humans
Infection symptoms: After humans are infected with the Newcastle disease virus, they may experience mild influenza-like symptoms such as fever, cough, sore throat, and conjunctivitis. These symptoms are usually self-limiting and do not cause serious health problems.
High-risk groups: People who are engaged in poultry farming, veterinary work, or in close contact with infected birds are at higher risk of infection. Nevertheless, the vast majority of infected people do not show obvious symptoms.
Immune system effects: Viruses can cause more serious consequences in people with weak immune systems, but this is very rare.
What is the cause of Newcastle disease in chickens?
The cause of Newcastle disease in chickens is mainly caused by Newcastle disease virus (NDV), which is highly contagious and pathogenic and can infect a variety of birds, especially poultry. The following is a detailed description of the causes of Newcastle disease in chickens：
Types of Newcastle Disease virus
Newcastle disease virus is a single-stranded negative RNA virus belonging to the paramyxovirus family. According to its pathogenicity, NDV can be divided into three types：
Lentogenic: Low pathogenicity, usually manifested as mild symptoms.
Mesogenic: Moderately pathogenic, with more obvious symptoms.
Velogenic: Highly pathogenic, leading to serious clinical symptoms and high mortality.
Transmission route
The Newcastle disease virus is mainly transmitted through the following channels: direct contact, airborne transmission, and environmental pollution.
- Direct contact: The secretions (such as saliva, snot) and feces of sick chickens and poisonous chickens are the main sources of infection.When healthy chickens come into direct contact with these sick birds, the virus can enter the body through the skin or mucous membranes.
- Airborne transmission: The virus can be carried by mediators such as dust mites through droplets or feces and dust and spread through the air.
- The influence of environmental factors: Ambient temperature, humidity, and feeding density have a greater impact on the occurrence and spread of Newcastle disease.
Can chickens survive the Newcastle disease?
Whether chickens can survive after being infected with ND mainly depends on the type of virus they are infected with, the immune status of the chickens, and the effectiveness of epidemic prevention measures.
Chicken survival rate against different types of Newcastle disease
Highly pathogenic virus: Chickens infected with the velogenic Newcastle disease virus, especially unvaccinated chickens, can have a mortality rate of 55% to 100%.This virus usually causes death within 3 to 4 days, especially in young chicks and unvaccinated adult birds.
Moderate and low pathogenic viruses: the mesogenic and lentogenic Newcastle disease viruses are relatively mild. The mesogenic type may cause mild symptoms and low mortality, while the lentogenic type usually does not cause significant clinical diseases and is commonly used in vaccination. Chickens vaccinated with a lentogenic vaccine usually survive and show milder symptoms when exposed to the Newcastle disease virus.
Influencing factors
- Immune status: The survival rate of chickens vaccinated against Newcastle disease is significantly higher than that of unvaccinated chickens. Even in the face of strong strains, vaccinated chickens can effectively resist infection and reduce mortality.
- Age: Young chicks are particularly sensitive to the Newcastle disease virus, and the mortality rate after infection is higher than that of adult chickens.Therefore, young chicks are more susceptible when exposed to the virus.
- Environment and management: Good biosecurity measures and management practices can significantly reduce the risk of transmission of Newcastle disease, thereby improving the survival rate of chickens.
How to prevent Newcastle disease in chickens?
Preventing ND in chickens is an important measure to ensure the health and productivity of the poultry industry.
Regular vaccination：
- The chicks are vaccinated with the Newcastle disease strain Clone30 vaccine at the age of 7 to 10 days, usually by nasal drops or eye drops.
- The second vaccination is carried out at the age of 35 to 40 days.
- Chickens are vaccinated the Newcastle disease gene VII vaccine at the age of 2 to 3 months to enhance immunity.
- For laying hens, re-vaccinate gene VII vaccine 2 to 3 weeks before the start of the pregnancy to ensure protection during egg laying.
Vaccination route
- Eye drops/nose drops: After diluting the vaccine, use a standard dropper to drop 1 drop (about 0.05ml) into each of the chicken’s eyes or nostrils. This method is suitable for chicks.
- Drinking water vaccination: Dilute the vaccine in a solution of skim milk powder, and then let the chicken drink it. Be careful not to use tap water or well water directly so as not to affect the potency of the vaccine.
- Intramuscular injection: For certain types of vaccines (such as moderately virulent vaccines), intramuscular injection can be used. When injecting, pay attention to the angle and depth of the needle to avoid leakage.
Precautions
- Immunization interval: Avoid frequent vaccinations and ensure that there is sufficient time interval between each vaccination to prevent immune fatigue.
- Drug interference: To prevent the vaccine’s effect from being affected, use antiviral drugs at least 36 hours before and after vaccination.
- Environmental control: When inoculating, ensure that the chickens are in a quiet and comfortable environment to reduce stress response.
Emergency vaccination: Once a new infectious disease epidemic is found, emergency vaccination of healthy chickens is immediately carried out to reduce mortality. Priority should be given to inoculation of healthy chickens and then inoculation of suspected sick chickens.
Biosecurity measures: Strengthen breeding management, reduce breeding density, reduce stress, and improve the overall health of the flock.
- Strictly isolate newly introduced chickens to ensure that they are quarantined and observed before entering the main flock.
- It is forbidden to introduce chickens, feed and breeding equipment from the affected areas, and avoid contact with personnel in the affected areas.
Environmental disinfection: Regularly clean and disinfect the chicken coop and its surrounding environment, and use effective disinfectants to treat areas that may be contaminated.
- Ensure that personnel and vehicles are strictly disinfected before entering the chicken coop.
Monitoring and quarantine: Establish a regular monitoring mechanism, conduct health checks on the chickens, and detect and deal with suspicious cases in a timely manner.
- Strengthen the quarantine supervision of poultry to ensure animal health and safety during transportation and trading.
Education and training: Through training, farmers can improve their awareness of the new urban epidemic and their prevention and control skills.
Chicken Newcastle Disease Vaccine Series
How to treat chicken newcastle disease?
Emergency immunization
- For chickens that become ill, isolate them in time.
- Healthy chickens can be vaccinated with the Newcastle disease La Sota vaccine with 6 times the amount of drinking water to enhance their immune response.
- Add levofloxacin powder (at a ratio of 0.01%) to drinking water and treat chickens continuously for three days to prevent secondary infections.
Medication
- Fluphenicol: To improve disease resistance, add it to the feed (at a ratio of 0.05%) and use it for three consecutive days.
- Tylosin: To help control secondary bacterial infections, it can be added to drinking water (at a ratio of 0.01%) and used for three consecutive days.
Supportive therapy
- To supplement vitamins and electrolytes and enhance chickens’ resistance, add electrolytes (in a ratio of 0.10%) to the feed.
- Ensure a good environment in the chicken coop, control humidity, temperature and light, improve feed nutrition levels, and reduce stress.
Strict disinfection measures
- Isolate or eliminate sick chickens, and deal with sick and dead chickens and their feces in a timely manner.
- Disinfect the site, utensils, and environment, use effective disinfectants, and keep the chicken coop dry and clean.
FAQ
Can Newcastle Disease be cured?
There is currently no special treatment for Newcastle disease. After infection, the condition is mainly managed through supportive care and preventive measures. Antibiotics are usually used to prevent secondary infections, but this does not cure Newcastle disease. Effective preventive measures include strict biosafety management and vaccination.
Can chicken Newcastle disease be transmitted to dogs?
Chicken Newcastle disease virus (NDV) mainly affects birds, especially poultry. Although there are reports that the Newcastle disease virus can infect humans, there is no evidence that it can be transmitted to dogs or other mammals.
Will ducks be infected with Newcastle disease?
Yes, ducks can be infected with the Newcastle disease virus. Although ducks are usually less pathogenic to the Newcastle disease virus and often show asymptomatic infection, certain highly pathogenic virus strains can still cause disease and death in ducks. Ducks can not only be infected with the virus, but may also spread to other birds, including chickens.
