The Mink Circovirus Capsid Subunit Expressed by Recombinant Baculovirus Protects Minks against Refractory Diarrhea in Field.

Teng Chen,Ye Liu,Xuefei Sun,Rongliang Hu,Faming Miao,Xintao Zhou,Lidong Wang,Yanyan Zhang,Lijuan Mi,Shoufeng Zhang

doi:10.3390/v13040606

Abstract

Mink refractory diarrhea is a seasonal disease that occurs in many mink farms in China. Mink circovirus (MiCV) has been recognized as the causative agent of the disease. The aim of the study was to develop a subunit vaccine against mink refractory diarrhea. A recombinant baculovirus strain expressing the capsid protein was constructed using the baculovirus expression vector system (BEVS). A subunit vaccine was developed based on the capsid protein with appropriate adjuvant. Then, a field trial was carried out in two districts in order to evaluate the efficiency of the subunit vaccine. The field trial indicated that in total, only 1.8% of the minks developed typical diarrhea in the vaccinated group compared with 74.5% in the control group. The vaccination could significantly reduce the infection rate of MiCV among the mink herds and could restrain the virus’ shedding from feces. Furthermore, the vaccinated group had a higher average litter size in the following year compared to the control group. Collectively, the results indicated that the subunit vaccine based on the capsid protein can provide reliable protection against MiCV infection.

Highlights

Mink refractory diarrhea, called “autumn diarrhea” or “red and grey diarrhea”by local farmers, has appeared in mink farms in China since the mid-1980s
We aimed to utilize the baculovirus expression vector system (BEVS) to express the capsid protein of Mink circovirus (MiCV) and develop a subunit vaccine against mink refractory diarrhea
The recombinant baculoviruses were confirmed by PCR (Figure 1a)

Summary

Introduction

By local farmers, has appeared in mink farms in China since the mid-1980s. Usually 70–80% of minks on a farm develop diarrhea, anorexia, and poor fur quality, and 7−8% die as a result [1]. Due to the considerable economic loss caused by the disease, an autogenous vaccine, which was made using formalin-inactivated gut tissue suspension of the infected minks, was initially put into application. This strategy reduced the morbidity and partially controlled the disease for a period of time around the 2000s. After a few years of application, the vaccinated pedigree breeds appeared to show symptoms of Aleutian mink disease. The autogenous vaccine has been abandoned in recent years, and there is an urgent need for a safe and efficient vaccine to control the disease

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