Disease Defense
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1、 Introduction
Newcastle Disease (ND) is a highly contagious avian disease caused by members of the Paramyxoviridae family, posing a serious threat to the global poultry industry. This disease not only spreads rapidly and has a high mortality rate, but may also cause huge economic losses. This article will comprehensively explore the prevention and control strategies of Newcastle disease from the aspects of disease characteristics, transmission routes, clinical symptoms, diagnostic methods, and prevention and control measures. Relevant professional literature and international news reports will be cited to provide scientific and practical guidance for poultry farmers and veterinarians.
2、 Disease characteristics and transmission routes
（1） Pathogenic characteristics
The pathogen of Newcastle disease in chickens is avian paramyxovirus type 1 (APMV-1) of the family Paramyxoviridae, which has high variability and multiple genotypes have been identified. Viruses have strong resistance to the environment and can survive for a long time under low temperature and dry conditions, which increases the risk of disease transmission.
（2） Transmission route
• Horizontal transmission: transmitted through direct contact between infected chickens and healthy chickens, or through contaminated feed, water, air, equipment, etc.
• Vertical transmission: The virus can be transmitted to chicks by infecting the eggs of hens, but this mode of transmission is relatively rare.
• Wildlife transmission: Wild animals such as birds and mice can carry viruses and become vectors for disease transmission.
3、 Clinical symptoms
The clinical symptoms of Newcastle disease in chickens vary depending on factors such as the virulence of the infected virus, the immune status of chickens, and age, mainly including the following types:
• Acute type: The onset is rapid and the symptoms are obvious, including high fever, difficulty breathing, cough, runny nose, lethargy, decreased appetite, etc. Neurological symptoms such as ataxia and paralysis are also quite common.
• Subacute type: Mild symptoms, mainly manifested as mild respiratory and neurological symptoms, with relatively low mortality rate.
• Chronic type: Symptoms persist for a long time, mainly manifested as long-term respiratory and neurological symptoms, such as paralysis, claudication, etc.
4、 Diagnostic methods
（1） Clinical diagnosis
Based on the clinical symptoms and epidemiological history of the chickens, it is preliminarily determined whether it is Newcastle disease. However, clinical symptoms alone are difficult to distinguish from other similar diseases, so further laboratory testing is needed.
（2） Laboratory diagnosis
• Virus isolation: Samples were taken from the organs and brains of dead chickens, added to physiological saline and ground, and antibiotics were added. The urine cavity of chicken embryos at around 9 days of age was inoculated to observe the mortality and blood cell agglutination reaction of the embryos.
• Serological testing: The antibody levels in chicken serum are detected by serological methods, including hemagglutination inhibition test (HI) and enzyme-linked immunosorbent assay (ELISA).
• Molecular biology detection: Real time fluorescence quantitative PCR (qPCR) and other molecular biology methods are used to quickly and accurately detect viral nucleic acids.
5、 Prevention and control measures
（1） Immunization
• Vaccine selection: Choosing the appropriate vaccine is the key to preventing and controlling Newcastle disease in chickens. The commonly used vaccines currently include inactivated vaccines and live vaccines. Inactivated vaccines have high safety and stable immune efficacy; Live vaccines have good immune effects, but safety should be taken into account during use.
• Immune program: Develop a reasonable immune program based on the age, immune status, and breeding environment of the chickens. It is generally recommended that chicks receive their first immunization at 7-10 days of age and receive booster immunization 3-4 weeks later. Adult chickens are immunized 2-3 times a year.
• Immune efficacy monitoring: Regularly check the antibody levels in the serum of chickens to ensure immune efficacy. When the antibody level is below the protection threshold, timely immunization should be administered.
（2） Biosafety measures
• Isolation and disinfection: Newly introduced chickens are isolated and quarantined to ensure they are free from infection before being mixed and raised. Regularly disinfect the chicken coop, equipment, and environment to reduce the spread of viruses.
• Personnel management: Breeding personnel should change their work clothes and shoes before entering the chicken coop to avoid bringing the virus into the coop.
• Wildlife control: Take measures to prevent wild birds, mice and other wild animals from entering the chicken coop and reduce the risk of virus transmission.
（3） Disease monitoring and early warning
• Regular monitoring: Regularly monitor the health of the chicken flock and promptly detect any abnormal situations.
• Warning system: Establish a disease warning system, timely release epidemic information, and guide farmers to take prevention and control measures.
（4） Treatment measures
At present, there is no specific drug that can directly kill the Newcastle disease virus in chickens. Treatment mainly focuses on symptomatic treatment and supportive therapy
• Antibiotic treatment: Use antibiotics to prevent and treat secondary infections, reducing mortality rates.
• Nutritional support: Provides additional vitamins and minerals to enhance the immune system of chickens.
•Environmental management: Maintain a comfortable environment in the chicken coop and reduce stress factors.
6、 International Research and News Reporting
（1） International research progress
•Vaccine research: A 2023 study found that despite the existence of virus genotype mismatch, existing vaccines can still provide significant protection for chickens. This indicates that even if the virus mutates, vaccination remains an effective means of preventing and controlling Newcastle disease in chickens.
•Prevention and control strateg ies:A study in 2025 emphasized the importance of strengthening farmers' awareness of Newcastle disease and vaccination in rural areas of Africa. Research has shown that through training and community mobilization, vaccination rates can be significantly increased and disease transmission reduced.
（2） International news reports
•African Epidemic: On January 27, 2025, a research report on Newcastle disease in rural areas of Tanzania pointed out that although most farmers are aware of the disease, vaccination rates are still low. This indicates that raising farmers' awareness of prevention and control and improving vaccination conditions are the focus of current prevention and control work.
•Global prevention and control: On January 25, 2024, a report on vaccine challenge research pointed out that existing vaccine formulations still have good protective effects against contemporary virus strains. This provides a scientific basis for the prevention and control of Newcastle disease worldwide.
REFERENCES:
: Mramba, R. P., Mapunda, P. E., & Kisanga, A. C. (2025). Newcastle disease awareness and vaccination practices among indigenous chicken farmers in the Biharamulo district of Tanzania. Poultry Science and Management , 2, 1. https://poultrysciencemanagement.biomedcentral.com/articles/10.1186/s44364-025-00004-3: Molecular characterization of Newcastle disease virus in Tanzania. Springer , 2023. https://link.springer.com/article/10.1007/s42770-023-01159-z: Genetic Diversity of Newcastle Disease Virus in Tanzania. MDPI , 2023. https://www.mdpi.com/2306-7381/10/7/477: Participatory epidemiology of Newcastle disease across the Rift Valley in Manyoni District, Tanzania. Sokoine University of Agriculture , 2019. https://www.suaire.sua.ac.tz/bitstream/handle/123456789/3496/GEOFREY%20KISWAGA%20.pdf?sequence=1
