Non-Inferiority Field Study Comparing the Administrations by Conventional Needle-Syringe and Needle-Free Injectors of a Trivalent Vaccine Containing Porcine Circovirus Types 2a/2b and Mycoplasma hyopneumoniae.

Hyejean Cho,Taehwan Oh,Chanhee Chae,Yongjun Ahn,Jeongmin Suh

doi:10.3390/vaccines10030358

Abstract

The objective of this study was to assess the clinical, immunological, microbiological, and pathological evaluation of trivalent vaccine containing porcine circovirus types 2a/b (PCV2a/b) and Mycoplasma hyopneumoniae given by two different needle-free injection devices compared with conventional needle-syringe injection in a herd with subclinical PCV2d infection and enzootic pneumonia. A total of 240 21-day-old pigs, which weighed between 5 to 6 kg, were randomly divided into four groups (60 pigs per group, 30 = male and 30 = female per group). Injection site reactions in the pigs were minimal for the two needle-free injection devices and needle-syringe injection. Trivalent vaccination of pigs with two needle-free injection devices was not inferior to conventional needle-syringe injection for growth performance. Trivalent vaccination of pigs with two different needle-free injection devices reduced levels of PCV2d loads in serum and M. hyopneumoniae loads in the larynx equally compared to the conventional needle-syringe injection. The amount of PCV2d load in serum from the needle-free Pulse FX injection device at 49 days post vaccination showed non-inferiority to conventional needle-syringe injection. The immune response against PCV2 and M. hyopneumoniae to trivalent vaccine given with the needle-free Pulse FX injection device was non-inferior to conventional needle-syringe injection. The pigs from the two needle-free injection device and conventional needle-syringe injection had significantly (p < 0.05) lower macroscopic and microscopic lung lesion scores, and microscopic lymphoid lesions than from unvaccinated. The results of this study demonstrated that vaccination of trivalent vaccine by the two needle-free Pulse injection devices used in the study was non-inferior to that by conventional needle-syringe injection for growth performance, immune response against PCV2 and M. hyopneumoniae, and reduction of PCV2 viremia.

Highlights

Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae are two major economically important pathogens in global pork industry
PCV2 is the principal causative agent of porcine circovirus-associated disease (PCVAD), which was originally described as postweaning multisystemic wasting syndrome [1,2]
Subclinical PCV2 infection is currently the most common form of PCVAD [3]. Additional disease manifestations such as porcine respiratory disease complex (PRDC), and reproductive failure have been found in all ages of swine [1]

Summary

Introduction

Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae are two major economically important pathogens in global pork industry. Subclinical PCV2 infection is currently the most common form of PCVAD [3]. Additional disease manifestations such as porcine respiratory disease complex (PRDC), and reproductive failure have been found in all ages of swine [1]. As a primary contributor to PRDC, M. hyopneumoniae is the etiological agent of enzootic pneumonia [4]. It is not a new pathogen, for these reasons, it is one of the most economically devastating pathogens to the swine industry

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