Veterinary Vaccine最新文献

Vaccines are all biological substances produced from living things, administered to trigger the host's body defense system to develop immunity against a specific pathogen from which they are produced. They are produced either from the whole organism or parts of it. There are several types of vaccines like live virulent, live attenuated, inactivated (killed), subunit, toxoid, sero-vaccine, and autogenous vaccine. Vaccines work by stimulating either humoral or cell-mediated immunity or both to differentiate. Even though vaccination is the powerful and cost-effective weapon of disease prevention and control of infectious and non infectious diseases, there are factors those, hinder its effectiveness (constraints of vaccine effectiveness). These factors are technical constraints, pathogen-related constraints, vaccine-related factors, host-related and environmental and management-related constraints. While planning a vaccination regimen, it is important to test the potency of the vaccine, whether it much with circulating serotype, availability of cold chain, skilled manpower, the status of the target group and weather condition. Vaccine epidemiology, the study of vaccine interactions and impacts on the epidemiology of vaccine-preventable diseases also has an impact on vaccine effectiveness. it includes basic reproductive number, the force of infection, herd immunity, and epidemiologic shift. Some review papers mostly deal with constraints of specific vaccines and species of animals and with a specific constraint of the vaccine. However, the papers which review all common constraints of vaccine are limited. Therefore, this review paper is to address the most common constraints on the effectiveness of vaccines in all animal species and to highlight on evaluation of vaccine effectiveness and epidemiology.

Coccidiosis is an intestinal disease of poultry that endangers animal health and causes economic loss to poultry production. For decades, the control of the coccidiosis relies mainly on anticoccidial drugs and live vaccines. However, problems such as widespread of drug resistance, public health pressure after mass administration of anticoccidial drugs, and the risk of expansion of coccidia after administration of live avian coccidiosis vaccine make new anticoccidial alternatives urgent for health development of avian industry. A number of new vaccines have emerged recently, including recombinant vaccines, DNA vaccines and genetically engineered live vaccines. Additionally, various adjuvants, such as DNA adjuvants, recombinant adjuvants, plant-derived adjuvants, probiotics and prebiotics have been evaluated in animal trials. In this article, an overview of the host immune response to avian coccidia is presented, and current vaccine and adjuvant control strategies are outlined as well. It is hoped that this review will contribute to a deeper understanding of avian coccidiosis prevention and control strategies and lay a theoretical foundation in the field.

Outbreaks caused by Goose/Guangdong H5 highly pathogenic avian influenza (HPAI)-lineage viruses continue to occur in unprecedented numbers throughout Eurasia, the Middle East and Africa, causing billions of dollars in economic losses and the deaths or destruction of hundreds of millions of poultry, and pose a zoonotic threat. Here, a recombinant virus-like particle (VLP) displaying the hemagglutinin protein of a clade 2.3.4.4b H5N8 HPAI strain was produced in tobacco plants (Nicotiana benthamiana) and its immunogenicity with four commercial adjuvants was compared in layer hens. After two immunizations with 250 hemagglutinating unit doses, hens that received intramuscular injections of H5 VLPs formulated with Emulsigen D, Emulsigen P or Montanide ISA 71VG seroconverted with hemagglutination inhibition geometric mean titres (GMTs) of 7.3 log₂ (± 1.17), 8 log₂ (± 1.08) and 7.9 log₂ (±1.07), respectively, but the GMT of hens inoculated by eye drop with VLPs plus Carbigen only reached 2.05 log₂ (± 1.64). The H5 VLP plus Emulsigen-P vaccinated hens and a sham-vaccinated group were then challenged with a high dose of the homologous H5N8 HPAI virus. Vaccinated hens were completely protected and showed no clinical signs, whereas the sham-vaccinated birds all died within 3–4 days. The average oropharyngeal shedding in vaccinated hens was reduced by 3,487-fold and 472-fold on days 2 and 3 post challenge, respectively, whereas average cloacal shedding was reduced by 2,360,098-fold and 15,608-fold on days 2 and 3, respectively, compared to the sham-vaccinated controls. No virus was detected in the vaccinated hens after day 8 post challenge, and the plant-produced H5 VLP vaccine completely prevented H5N8 HPAI virus transmission to eggs. This highly efficacious, safe and non-toxic plant-produced H5 VLP vaccine with DIVA (differentiation of infected from vaccinated animals) capability could be rapidly produced with a yield of at least 85,000 doses per Kg of plant leaf material.

Newcastle disease (ND) is an infectious and economically important disease of poultry caused by virulent avian Paramyxovirus 1 (APMV-1). For decades, live and inactivated vaccines have been used as conventional therapy in poultry, even then failure is reported due to mismatch antigenicity, presence of maternal antibodies, cold chain disruption, and uneven vaccine applications. Many experimental vaccines have been in trial for many years, but the disease is still rampant in many parts of the world. From acute onset with high mortality to mild disease in birds, Newcastle disease virus potential as a vector has been exploited for the treatment of different cancers and vaccination of humans. The objective of this review is to understand the Newcastle disease virus, immune mechanism, prevention and control strategies adapted for the Newcastle disease in poultry, and its beneficial use as a candidate vector for human vaccines and cancer therapy.