Open Veterinary Journal, (2026), Vol. 16(4): -2343

Research Article

10.5455/OVJ.2026.v16.i4.33

---

Effectiveness of neem (Azadirachta indica) bark in treating newcastle disease in indigenous chickens

Nouri Brah^1*, Issa Hamadou¹, Mamman Mani¹ and Jens B. Aune²

¹Animal Production Department, National Institute for Agriculture Research of Niger, Niamey, Niger

²Faculty of Landscape and Society, Norwegian University of Life Sciences, Ås, Norway

*Corresponding Author: Nouri Brah. Animal Production Department, National Institute for Agriculture Research of Niger, Niamey, Niger. Email:brahnouri [at] yahoo.fr

Submitted: 07/09/2025 Revised: 11/03/2026 Accepted: 23/03/2026 Published: 30/04/2026

---

ABSTRACT

Background: Newcastle disease (ND) is the primary constraint on local chicken production in family poultry farming systems in Niger. During epidemic periods, producers commonly resort to locally available resources to manage the disease.

Aim: This study aimed to evaluate the efficacy of the infusion of neem bark (Azadirachta indica) in water for treating ND.

Methods: Eighty local chickens were allocated across two experimental sites. The chickens were further divided into four treatment groups within each site. Each group received ad libitum access to drinking water containing neem bark treatment for 2 weeks. The treatments consisted of T0, T13, T26, and T39, corresponding to 0, 13, 26, and 39 g of neem bark per liter of water, respectively. The data collected included feed intake, live weight of chickens, disease prevalence, and mortality rates. Statistical analyses were performed using R software. Orthogonal polynomial contrasts were applied to evaluate the linear and quadratic responses to the different doses of neem bark for treating ND. Survival analysis was performed to determine mortality.

Results: Indicated a general decline in feed intake and live weight across all groups. The disease prevalence increased, but without significant linear or quadratic effects (p > 0.05). Throughout the experiment, the disease continued to spread and affected the health of the chickens. Mortality averaged 71.3% during the experiment period.

Conclusion: This study underscores the importance of using traditional vaccines as the main approach to prevent disease outbreaks. No therapeutic benefit was observed from using neem bark in chicken drinking water for ND treatment.

Keywords: Local chickens, Neem bark, Newcastle disease, Niger, Treatment.

---

Introduction

Poultry farming is widespread and plays a crucial role in meeting the domestic and economic needs of millions of smallholder farmers who are predominantly poor (Issa et al., 2012). In most tropical countries, traditional scavenging systems are primarily used for poultry production. It is estimated that 80% of Africa’s poultry population is raised under such systems, with women and children typically responsible for poultry management (Riise et al., 2005). In Niger, local breeds account for 96% of the poultry population, whereas modern breeds account for only 4% (Moussa et al., 2019).

Newcastle disease (ND), the most serious epizootic poultry disease that threatens the global poultry industry (El Basuni et al., 2023), occurs every year and kills, on average, 70%–80% of unvaccinated rural family poultry flocks (Guèye, 2002). ND is a highly contagious viral infection that affects domestic and wild birds worldwide and is classified as a notifiable disease by the World Organization for Animal Health (Megahed et al., 2020). Typically, ND outbreaks occur annually in rural areas (Guèye, 2002).

The general approaches to ND control include biosecurity and vaccination (Abdisa and Tagesu, 2017). However, organizing vaccination campaigns for free-range poultry remains extremely challenging. Maintaining the cold chain to preserve thermolabile antigens in vaccines presents significant challenges (Dimitrov et al., 2017). In addition, farmers are often required to keep their chickens confined and to pay for the service on the day of vaccination (Bagnol et al., 2013). The cost of vaccinating 10 chickens for a 3-month period of protection has been estimated at USD 2.64 (Campbell et al., 2019). Traditional natural products, particularly plant-based remedies, are commonly used for the treatment of bacterial and viral infections in humans and animals (Elsherbini et al., 2025) and, in some cases, for the prevention of ND (Guèye, 2002). Purified natural products and herbal medicines represent a valuable resource for developing new antiviral drugs (Ali et al., 2019). Various plant parts, including shoots, flowers, roots, bark, leaves, and fruits, individually or synergistically, have demonstrated promising antimicrobial activities (Mehmood et al., 2018). Interest in the use of medicinal plants for veterinary purposes has grown in recent years, largely because they are less likely to cause resistance or environmental side effects than synthetic drugs. Due to the simplicity of preparation and administration, as well as their accessibility, herbal remedies hold an important place in livestock breeders’ practices (Merazi et al., 2016).

Azadirachta indica, commonly known as neem, is predominantly found in the southern regions of Asia and Africa, where it has been used in traditional medicine for centuries (Islas et al., 2020). In recent years, it has gained worldwide recognition because of its broad spectrum of medicinal properties, including anti-diabetic, antioxidant, antiviral, and anti-inflammatory activities (Uzzaman, 2020). Some of these chemical constituents are Nimbidin, Nimbin, Nimbolide, Gedunin, Azadirachtin, Mahmoodin, Cyclic trisulfide, and others, which are used as antipyretic, anti-inflammatory, antibacterial, antigastric ulcer, antiarthritic, spermicidal, antifungal, antimalarial, hypoglycemic, immunomodulatory, diuretic, and antitumor agents (Eid et al., 2017). However, most of the use of neem involves the leaves (Ali et al., 2021; Ahmadi et al., 2024). Information on the use of other parts of the plant, such as the bark, which has antiviral activities (Mahmood, 2018), is lacking. In Niger, within the framework of the “Research-development project for food security and climate change adaptation”, chicken producers in the Tahoua region have identified the use of neem bark infused in drinking water for ND treatment as an innovative local practice. To evaluate the effectiveness of this practice and supplement the information on the antiviral activities of the neem bark, a study was conducted by the animal production component of the project, under the supervision of the Animal Production Department of the National Institute of Agronomic Research of Niger. This study aimed to evaluate different doses of neem bark in drinking water to treat ND in local chickens.

---

Materials and Methods

Experimental site and poultry house

The experiment was conducted simultaneously in Nassarawa in the Tahoua region and Maradi city in the Maradi region. These sites are located approximately 120 km apart. The poultry shelter at both sites had a surface area of 17.5 m² (5 × 3.5 m) and was constructed using local materials. The experimental site in Maradi was the Regional Agronomic Research Center, whereas in Tahoua, it was at a local chicken producer. At each site, four blocks were prepared within the poultry houses, each measuring 4 m² and enclosed with fine mesh wire.

Experimental design

A total of 80 local chickens, 40 per experimental site, were purchased from villages and local markets. The chickens were acquired during the typical period of ND outbreaks in Niger, specifically from areas where vaccination is not practiced. At each site, the chickens were divided into four groups (blocks) of 10 birds each, ensuring similar average live weights across blocks. Each group received a distinct treatment over the 2-week experimental period. The study site was used as a repetition in the statistical analysis.

Preparation of neem bark treatment

Four treatments, based on the neem bark method traditionally used by villagers in Nassarawa, were evaluated:

• T0 (control): drinking water without neem bark.
• T13: Drinking water containing 13-g neem bark per liter.
• T26: Drinking water containing 26-g neem bark per liter (corresponding to the practice of traditional Nassarawa villagers).
• T39: Drinking water containing 39-g neem bark per liter.

Monitoring zootechnical performance

All chickens received the same commercially available feed purchased from local markets. Feed, intended for laying hens, was provided in granulated form and distributed daily. The distribution of feed quantities and the refusals were systematically recorded. Feed intake was calculated as the difference between the amount distributed and the amount refused, adjusted for the number of chickens present each day. Feed intake was expressed in grams per day per chicken.

All chickens were individually weighed at the beginning, middle, and end of the experiment. The average live weight per treatment group at each weighing was calculated by dividing the total weight of the group by the number of chickens present at the time of weighing. Live weight was expressed in grams per chicken.

Serological monitoring

A blood sample of 1 ml per chicken was collected at the beginning, middle, and end of the 2 weeks of the experiment. Samples were sent to the Central Livestock Laboratory (LABOCEL) in Niamey for indirect enzyme-linked immunosorbent assay for the detection of antibodies to ND virus in chicken serum to monitor the serological evolution during the study. The disease prevalence was calculated as the percentage of chickens affected by ND at each sampling point.

All mortality was recorded throughout the experiment. The mortality rate, expressed as a percentage (%), was calculated at the midpoint and at the end of the study by determining the difference between the initial and final number of chickens relative to the initial number, and expressed as a percentage. The average mortality rate per treatment group was similarly calculated based on the difference in the number of chickens at the start and end of the experiment relative to the initial number.

Data processing and statistical analysis

All data were entered and organized using Microsoft Excel^® 2013. Statistical analyses were performed using the R software (version 4.3.3). Analysis of variance was performed to assess differences in feed intake, body weight, and disease prevalence. Orthogonal polynomial contrasts were employed to test for linear and quadratic responses to different doses of neem bark in drinking water for ND treatment. Differences between treatment means were compared using the Student-Newman-Keuls test at a 5% significance level. For mortality, the Kaplan–Meier analysis method was used to estimate the survival function of different treatment groups over the experimentation period. The log-rank test was used for statistical comparisons between groups.

Ethical approval

This experiment was conducted in compliance with the current standards of the National Institute for Agriculture Research of Niger (INRAN) for conducting experiments with animals. Ethical issues, such as plagiarism, consent to publish, misconduct, data fabrication and falsification, double publication and submission, and redundancy, have been checked by all the authors.

---

Results

Zootechnical performances

Feed intake of chickens

During the first week of the experiment, chickens receiving drinking water containing 39 g of neem bark per liter (T39) exhibited the highest feed intake, followed by those in the control group (T0). Chickens in treatments T13 (13 g/l) and T26 (26 g/l) exhibited similar feed intakes during the same period (Table 1). However, these differences were not statistically significant in the linear (p=0.21) or quadratic (p=0.31) analyses. In the second week, feed intake decreased for treatments T0, T26, and T39, whereas feed intake increased in the T13 group. The difference in feed intake among treatments during the second week was statistically significant (p < 0.05).

Over the entire duration of the experiment, chickens in the T13 treatment group exhibited the highest feed intake (Table 1), exceeding the intake of chickens in treatments T0, T26, and T39 by 7.90, 6.69, and 4.74 g/d, respectively. However, these differences were not statistically significant (p > 0.05), regardless of the applied contrast level.

Table 1. Feed ingestion (g/d) of local chickens during the experiment.

Live weight of the chickens

At the start of the experiment, the chickens in treatment T13 had the highest initial live weight at 889.7 g, compared with 855, 786.3, and 852.35 g in treatments T0, T26, and T39, respectively (Table 2). However, these differences were not statistically significant (p  >  0.05). After 1 week, the T13 chickens gained weight, whereas those in the other treatments lost weight, although these changes were not statistically significant (linear p = 0.11; quadratic p = 0.50). At the end of the experiment, chickens in treatment T13 exhibited a weight gain of 85.7 g compared to their initial weight (Table 2), whereas chickens in treatments T0, T26, and T39 exhibited weight losses of 245.0, 124.0, and 139.9 g, respectively. However, these differences were not significant. In contrast to the losses in other treatments, the weight gain observed in T13 is likely attributable to its higher initial live weight, which may have provided a physiological advantage under the experimental conditions. The weight loss observed for treatments T0, T26, and T39 was due to reduced feed intake due to the disease.

Table 2. Evolution of live weight (g) of local chickens during the experiment.

Serological monitoring

Prevalence of ND

At the start of the experiment, all treatments had chickens infected with ND (Table 3). Treatments T26 and T0 had more affected subjects than treatments T13 and T39. These differences in the initial prevalence were not statistically significant (p > 0).

One week later, the disease prevalence increased in all treatments. Chickens in treatment T0 that were more contaminated (Table 3) exceeded chickens in treatments T13, T26, and T39 by 2.62%, 5.39%, and 1.91%, respectively. However, this difference was not significant (p > 0), regardless of the contrast used.

At the end of the experiment, ND affected all chickens in the T0 and T39 treatment groups (Table 3). In contrast, T13 and T26 had 20% and 14.29% of chickens, respectively, that remained uninfected (Table 3). However, neither linear nor quadratic comparisons were statistically significant at the 5% confidence level (p > 0).

Table 3. Prevalence of ND according to treatment.

Mortality of the chickens

There was a significant difference (p < 0) in the survival rate between the treatments (Fig. 1). The mortality rate was significantly higher in the T13 and T26 treatment groups in the first week. T0 had the highest survival rate this week. T39 had an average survival rate (Fig. 1). At the end of the experiment, T39 showed more resistance to the disease and had the highest survival rate, whereas T13 had the lowest survival rate. The survival rate varied from 50% (T39) to 10% (T13), which represents a very high mortality rate over a 2-week period. These results also highlight the severity of the disease problems for poultry farmers, especially considering that the chickens were sourced from the local market.

Fig. 1. Kaplan Meier survival curve of different treatment.

---

Discussion

Zootechnical performances

Feed intake of chickens

The feed ingestion findings are consistent with those of Olorungbohunmi (2022)who reported no significant differences in feed intake among birds receiving Moringa oleifera and A. indica as an alternative to antibiotics. The decrease in feed intake observed across treatments was likely associated with ND infection, as typical clinical signs include greenish diarrhea, depression, and loss of appetite (Abdisa and Tagesu, 2017).

Live weight of the chickens

A positive effect of neem treatments was demonstrated by other studies. Results from Mohammad (2016)demonstrated that neem infusion significantly improved antibody titers, growth performance, and gross return when administered at a concentration of 50 ml per liter of fresh drinking water. In the present study, the observed decrease in live weight was attributed to the occurrence of disease, which led to a reduction in feed intake. Indeed, the reduction in live weight is likely due to multiple organs’ metabolic disturbances induced by viral infection, leading to impaired feed digestion. ND virus damages pancreatic tissue, resulting in decreased production and activity of digestive enzymes, elevated levels of corticosterone and somatostatin, and reduced insulin secretion, ultimately compromising growth performance (Zhang et al., 2023). The weight gain observed in the T13 group was likely due to mortality predominantly affecting chickens with lower body weights.

Serological monitoring

Prevalence of ND

In a study conducted by Ahamidou et al. (2023)the prevalence of ND in local poultry in Maradi was 46.7%, which is lower than the prevalence observed in the present study. Despite continuous and ad libitum treatments, the ND virus infection continued to spread in our experiment. No therapeutic benefit was observed under these field conditions. It appears that neem antiviral properties are restricted to certain viruses (Ahmadi et al., 2024), but T39 demonstrated a certain effectiveness. This suggests that the different doses applied in our study were not sufficient to inactivate the virus, because it was determined that neem bark extract concentrations lower than 0.87 mg/ml did not affect the attachment of Bovine Parainfluenza Virus-3 and Bovine Entero Virus (Aslim et al., 2025).

Mortality of the chickens

These high mortality rates cannot be considered a surprise because highly virulent velogenic strains of Newcastle Disease Virus (NDV) can cause mortality rates of up to 100% in highly susceptible flocks (WOAH, 2022). The different doses used were insufficient to inactivate the viruses. Indeed, Aslim et al. (2025)observed the in vitro antiviral activity of neem bark extract on bovine herpes virus-1 (BHV-1) at 0.87 mg/ml. But also, Mahmood (2018)found that at 1:2 dilution of Neem bark extract, antiviral activity on NDV was exhibited during in vitro evaluation, with higher dilution (1:8) showing non-significant antiviral activity. Viscotropic velogenic NDV infection leads to severe clinical manifestations in chickens, including dehydration, emaciation of carcasses, hemorrhagic lesions, and necrotic ulcerations at the tips of the proventricular glands, as well as in the intestine, cecal tonsils, and spleen parenchyma (Moustapha et al., 2023).

These results contradict the observations of Olorungbohunmi (2022)who reported that chickens not consuming neem leaf meal exhibited significantly higher mortality rates than those consuming neem leaf meal. ND is a very severe disease for poultry farmers, and it is important that they receive appropriate advice. Large-scale commercial flocks, such as layers and broilers, are predominantly treated with modern veterinary drugs (Lagu and Kayanja, 2010). Our study found that T39 presents a moderate mortality rate, but further studies are required for its use.

At this stage, vaccination is recommended even in small-scale poultry production. However, cost and availability are constraints for farmers to use this approach. It is difficult for an individual farmer to vaccinate the flock due to the start-up cost; therefore, it is best organized at the village level. Studies from Nigeria found a value-cost ratio of 2 for vaccination against the ND (Nwanta et al., 2005). The cost of vaccination of one chicken is below 0.1 US$ in the Republic of Niger.

Limitations

The strain characteristics of NDV and the chemical neem preparation were not verified before experimentation. In addition to these parameters, controlled challenge trials with Reverse Transcription Polymerase Chain Reaction confirmation and phytochemical standardization are needed for further study.

---

Conclusion

This study found that T39 showed a therapeutic benefit with a survival rate of 50%. The other treatments had a survival rate of 10%–20%. Despite the use of neem extract, the zootechnical performance of the chickens declined over time, the disease continued to progress, and the mortality rates remained high. On average, mortality across the treatment groups reached 70%.

Repeating the experiment is necessary, especially with a lower T39 dose than the T39 dose at more than two sites. This should be accompanied by the characterization of the virus strain and the neem bark’s physicochemical composition. In the meantime, vaccination remains a preventive measure against ND. Given the low cost of vaccination, it is strongly recommended as the main strategy for disease prevention, even in rural areas of Niger. Vaccination campaigns should be organized to ensure that small-scale poultry producers have reliable and affordable access to vaccines.

---

Acknowledgment

The authors are grateful to all the contributors to this study, particularly NORAD, the National Institute for Agricultural Research of Niger (INRAN), and Care International in Niger.

Conflicts of interest

The authors have no conflicts of interest to declare for this article.

Funding

This work was supported by the research-development project for food security and climate change adaptation (REDSAACC). Implemented in Niger through a consortium composed of the National Institute for Agricultural Research of Niger (INRAN), Care International in Niger, and NMBU, the Norwegian Agency for Development Cooperation (NORAD) is the prime sponsor.

Author contributions

Nouri Brah, Issa Hamadou, and Mamman Mani designed the study methodology and wrote the research protocol. Nouri Brah and Issa Hamadou supervised data collection. Aune played a significant role in data analysis and manuscript redaction. The authorship team worked together to ensure the quality and coherence of the manuscript regarding the draft preparation and subsequent revision. All authors have checked and approved the final version of this manuscript.

Data availability

All data supporting this study’s findings are available within the manuscript. For inquiries, please contact the corresponding author/s.

---

References

Abdisa, T. and Tagesu, T. 2017. Review on newcastle disease of poultry and its public health importance. J. Vet. Sci. Technol. 8, 441; doi:10.4262/2157-7579.1000441

Ahamidou, M., Essodina, T., Adamou, A. and Haladou, G. 2023. Impact and prevalence of Newcastle disease and associated risk factors in village chickens in southern Niger. Online J. Anim. Feed Res. 13(3), 209–216; doi: 10.51227/ojafr.2023.32

Ahmadi, K., Farzanehpour, M., Malekara, E., Aghaie Tabaeezavareh, S.M., Esmaeili, S.M., Gouvarchin., Ghaleh, H. and Mirzaei Nodooshan, M. 2024. Concise review on herbal medicine effects on combating newcastle disease virus as a threat to the poultry industry. J. Appl. Biotechnol. Rep. 11(2), 1282–1288; doi:10.30491/JABR.2022.356753.1557

Ali, E., Islam, S., Hossen, I., Khatun, M. and Islam, A. 2021. Neem extract (Azadirachta indica) leaf exhibits bactericidal effect against multidrug resistant pathogenic bacteria of poultry. Vet. Med. Sci. 7, 1921–1927; doi:10.1002/vms3.511

Ali , J.A., Al-Shammarie, A.M. and Al-Hameed, H.A. 2019. Antiviral activity of limonin against the newcastle disease virus _{in vitro}. J. Biotechnol. 14(Special Issue I).

Aslim, H.P., Palanci, S.H. and Bulut, O. 2025. _{In vitro} antiviral activity of neem (Azadirachta indica L.) bark extract against BCoV, BHV-1, BPIV-3, and BEV. Vet. Arhiv. 95, 75–88; doi:10.24099/vet.arhiv.2521

Bagnol, B., Alders, G.R., Costa, R., Lauchande, C., Monteiro, J., Msami, H., Mgomezulu, R., Zandamela, A. and Young, M. 2013. Contributing factors for successful vaccination campaigns against Newcastle disease. Livest. Res. Rur. Dev. 25(6), Available via http://www.lrrd.org/lrrd25/6/bagn25095.htm

Campbell, Z.A., Otieno, L., Shirima, G.M., Marsh, T.L. and Palmer, G.H. 2019. Drivers of vaccination preferences to protect a low-value livestock resource: willingness to pay for newcastle disease vaccines by smallholder households. Vaccine 37(11), 11–18; doi:10.1016/j.vaccine.2018.11.058

Dimitrov, K.M., Afonso, C.L., Yu, Q. and Miller, P.J. 2017. Newcastle disease vaccines-A solved problem or a continuous challenge?. Vet. Microbiol. 206, 126–136; doi:10.1016/j.vetmic.2016.12.019

Eid, A., Jaradat, N. and Elmarzugi, N. 2017. A review of chemical constituents and traditional usage of neem plant (Azadirachta indica). Pal. Med. Pharm. J. 2(2), 3; doi:10.5904/27900-0231.1060

El Basuni, S., Osman, M., Soliman, R., Magdy, Y., Abdalla, H.E. and Fathy, R. 2023. An alternative antiviral therapy of newcastle disease in broiler chickens: a clinical study of methanolic neem leaf extract. Slov. Vet. Res. 60(Suppl 25), 271–280; doi:10.26873/SVR-1593-2022

Elsherbini, M., Ali, A., Ahmed, F. and Kotb, G. 2025. Antiviral effects of herbal extracts against avian influenza and Newcastle disease viruses. Open. Vet. J. 15(8), 3388–3398; doi:10.5455/OVJ.2025.v15.i8.3

Guèye, E.F. 2002. Newcastle disease in family poultry: prospects for its control through ethno veterinary medicine. Livest. Res. Rur. Dev. 14(5), Available via http://www.lrrd.org/lrrd14/5/guey145a.htm

Islas, J.F., Acosta, E., G-Buentello, Z., Delgado-Gallegos, J.L., Moreno-Trevino, M.G., Escalante, B.E. and Moreno-Cuevas, J. 2020. An overview of neem (Azadirachta indica) and its potential impact on health. J. Func. Foods 74, 104171; doi:10.1016/j.jff.2020.104171

Issa, Y., Mopate, L.Y. and Missohou, A. 2012. Commercialization et consommation de la volaille traditionnelle en Afrique subsaharienne. J. Anim. Plant. Sci. 14(3), 1985–1995.

Lagu, C. and Kayanja, F.I.B. 2010. Medicinal plant extracts widely used in the control of newcastle disease (NCD) and helminthosis among village chickens of South Western Uganda. Livest. Res. Rur. Dev. 22(11). Available via http://www.lrrd.org/lrrd22/11/lagu22200.htm

Mahmood, M.S. 2018. Evaluation of antiviral activity of Azadirachta indica (Neem) bark extract against newcastle disease virus. Pak. Vet. J. 38(1), 25–28; doi:10.29261/pakvetj/2018.005

Mehmood, S., Abbasi, A.M., Hussain, H., Khan, S.A., Almutairi, H.H., Ismail, A.M., Al Saikhan S.M. and El-Beltagi, H.S. 2024. Phytochemical profile, antioxidant and antibacterial activities analysis of crude extract and essential oil of Pinus roxburghii and Pinus wallichiana: in vitro and in silico analyses. Cogent Food Agrci. 10(1), 2403648; doi: 10.1080/23311932.2024.2403648

Merazi, Y., Hammadi, K. And Fedoul, F.F. 2016. Approche Ethno-Vétérinaire Des Plantes Médicinales Utilisées Dans La Région De Sidi Bel Abbes- Algérie. Eur. Sci. J. 12(18), 218–231; doi: 10.19044/esj.2016.v12n18p218

Megahed, M., Mohamed, W. and Hassanin, O. 2020. A complex genetic diversity of newcastle disease virus (NDV) in Africa continent: an updated review. J. Anim. Health Prod. 9(s1), 97–109; doi:10.17582/journal.jahp/2020/9.s1.97.109

Mohammad, A.A. 2016. Therapeutics role of Azadirachta indica (neem) and their active constituents in diseases prevention and treatment. Evi. Compl. Altern. Med. 7382506,11; doi: 10.1155/2016/7382506

Moussa, H.O., Keambou, T.C., Hima, K., Issa, S., Motsa’A, S.J. and Bakasso, Y. 2019. Indigenous chicken production in Niger. Vet. Anim. Sci. 7, 100040; doi:10.1016/j.vas.2018.11.001

Moustapha, A., Talaki, E., Akourki, A. and Ousseini, M. 2023. Newcastle disease virus in poultry: current status and control prospects. World’s. Vet. J. 13(2), 240–249; doi:10.54203/scil.2023.wvj26

Muhammad, D.M., Ejaz, R., Huma, A., Sana, N., Mehreen, G. and Sajad, H. 2018. Antiviral activity and its prospective mechanism of action on Newcastle disease virus using crude extract of four medicinal plants. World J. Pharm. Res. 7(18), 130–141; doi:10.20959/wjpr201818-13444

Nwanta, J.A., Umoh, J.U., Abdu, P.A., Ajogi, I. and Egege, S.C. 2005. Comparison of the cost of unvaccinated and oral vaccinated local chickens with a Malaysian thermostable Newcastle disease vaccine (NDV4HR) in Kaduna State, Nigeria. Bul. Anim. Health Prod. Afri. 53(3), 203–210; doi:10.4314/bahpa.v53i3.32711

Olorungbohunmi, T.O. 2022. Growth performance and gut health of broilers fed Moringa oleifera and Azardiracta indica as an alternative to antibiotics. Nige. J. Anim. Prod. 49(3), 186–194; doi:10.51791/njap.v49i3.3551

Riise, J.C., Permin, A. and Kryger, K.N. 2005. Strategies for developing family poultry production at village level–experiences from West Africa and Asia. Worlds. Poult. Sci. J. 61; doi:10.1079/WPS200437

Uzzaman, S. 2020. Pharmacological activities of neem (Azadirachta indica): a review. Int. J. Pharmacol. Life. Sci. 1(1), 38–41; doi:10.33545/27072827.2020.v1.i1a.8

World Organization of Animal Health (WOAH). 2022. Manual of diagnostic tests and vaccines for terrestrial animals 2022. Paris, France: World Organisation for Animal Health. Available via https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-manual-online-access/

Zhang, D., Ding, Z. and Xu, X. 2023. Pathologic mechanisms of the newcastle disease virus. Viruses 15, 864; doi:10.3390/v15040864