Humans and animals have a close relationship with a large number of various types of microorganisms that colonize the gut and accompany the host throughout the life. An increasing amount of attention is being paid to the deeper exploration of the effect of this association. Symbiotic microorganisms in the gut regulate not only the absorption and metabolism of nutrients ingested by the host but also the formation and development of the host immune system. Many studies have reported that intestinal microorganisms interact with the central nervous system to form a two-way communication system, known as the brain-gut axis. Intestinal microorganisms can affect the occurrence and development of diseases of nervous system. Additionally, they regulate the permeability of the blood-brain barrier and inflammation in the brain by regulating the nervous system. In this mini-review, we describe the effects of intestinal microorganisms on the development and function of the brain and central nervous system-related diseases.

Bovine viral diarrhea virus is divided into two genotypes:genotype 1 (BVDV-1) and genotype 2 (BVDV-2).Previous epidemiological survey showed BVDV-1 isolates distributed more widely.However,the mobidity rate of BVDV-2 is increasing in recent years.In general,BVDV-2 infection can cause more severe disease characterized by acute infection and haemorrhagic syndrome,causing enormous losses to the cattle industry.In this review,we dilate on the following aspects:the establishment of the specific detection and genotyping methods of BVDV-2,the isolation and identification of BVDV-2,complete genomic sequencing and phylogenetic analyzation of BVDV-2 isolates,and the establishment of detection platform to virus and antibody of BVDV-1 and BVDV-2.