Epidemiological Investigation and Analysis of Major Viral Diseases of Pig Farms in Guangxi from 2019 to 2022

In order to understand the epidemic characteristics of major viral infectious diseases of pig farms in Guangxi from 2019 to 2022,the PCR and RT-PCR methods were applied to detect the pathogens of 1046 samples suspected CSFV(swine fever virus),PRRSV(porcine reproductive and respiratory syndrome virus),PCV-2(porcine circovirus virus type 2),PCV-3(porcine circovirus virus type 3),PRV(pseudorabies virus),TGEV(transmissible gastroeneritis of pigs virus),PEDV(porcine epidemic diarrhea virus)and PoRV(porcine rotavirus)infections in recent four years,and epidemiological analysis was carried out.The results showed that positive rates of CSFV,PRRSV,PCV-2,PCV-3,PRV,TGEV,PEDV and PoRV were 3.91%(21/537),20.46%(143/699),29.90%(116/388),16.10%(81/503),27.75%(121/436),2.10%(8/381),28.50%(61/214)and 13.74%(18/131).The infection rates of PCV-2 and PEDV were decreasing year by year,while the infection rate of TGEV was increasing year by year.In single infection,the infection rates of PRV and PEDV were higher,with an average infection rate of 13.53%and 18.22%.In the mixed infection,the infection rate of PRRSV and PCV-2 was the highest,with an average infection rate of 11.34%.The second mixed infection rate was PEDV and PoRV,and the average infection rate was 8.05%.The infection rate of PCV-3 and PEDV was higher in spring,with 18.80%and 40.00%respectively.The infection rate of PRRSV,PCV-2,PRV,TGEV and PoRV was higher in winter,with 24.40%,40.57%,37.30%,3.23%and 19.44%respectively.The results showed that PRRSV,PCV-2,PRV and PEDV were the main viral diseases with serious damage to pig farms in Guangxi.It was necessary to strengthen pathogen monitoring and improve comprehensive prevention and control ability,in order to reduce the incidence of disease and economic losses.

Phylogenetic Analysis of HN Gene of Eight Pigeon NDV Isolates in Guangxi

[Objective] The paper was to provide a basis for scientific prevention and control of pigeon Newcastle disease（ND）.[Method] The HN gene of eight pigeon NDV strains isolated from different pigeon farms in Guangxi were amplified by RT-PCR,sequenced and analyzed.The molecular evolution characteristics of HN gene of pigeon NDV isolates in Guangxi was discussed.[Result] The nucleotide sequence length of HN gene of the eight NDV isolates was 1 716 bp,encoding 571 amino acids.They belonged to virulent group C,and the gene length characteristic of HN gene accorded with virulent strain.Analysis of nucleotide homologies indicated that the eight NDV isolates shared higher homology with genotype VIb,ranging from 90.4% to 99.5%.Phylogenetic tree analysis demonstrated that the genetic relationship between the eight NDV strains in Gangxi and the NDV isolates from Guangxi,Guangdong,Jilin,Liaoning,Yunnan and Heilongjiang during 2011 and 2013 was close.They were located in the same cladogram branch.[Conclusion] We assume that the eight pigeon NDV isolates in Guangxi all belong to the gene class II genotype VI b NDV.