猪流感病因及防治浅析

猪流感（S1）是电正粘病毒科猪流感病毒（SIV）引起的猪的一种急性、高度接触传染性的呼吸道疾病，以突发、咳嗽、呼吸困难、发热、衰竭、迅速康复或死亡为特征。该病多发生在冬季或春季，气候变化是主要诱因。可发生于各年龄和各品种猪，一年四季均可流行，发病率高达100％。只有了解猪流感病的病因之后才好实施相对应的防治措施。

浅谈新型猪流感病防治

新型猪流感病毒变化多、攻击性强,一旦感染,潜伏期较长,不易发现,是一种难以预防的人畜共患病,不仅对养猪业生产危害大,而且对人类健康也有潜在威胁。

猪疫病防控及具体治疗措施

本文旨在探讨猪疫病的防控及治疗措施。文中对常见的猪疫病进行了简要分析,诸如猪瘟、猪流行性腹泻、猪流感病和猪繁殖与呼吸综合征等。在此基础上讨论了猪疫病防控的具体措施,如控制病原进入猪场、定时保健预防、猪栏的卫生消毒,同时也针对这些常见疾病提出了具体的治疗方案。

如何预防和治疗猪口蹄疫、流感猪病

在现代大规模养殖产业中，猪的养殖是非常普遍的，其原因是由于猪的需求非常大。由于现在一般都是大面积和规模化养殖，这就容易造成疾病的产生和传染，特别是猪口蹄疫、猪流感等疾病的发生，这种疾病的发生一般都是大面积产生，而且传染性比较强，容易令养殖户产生较大的经济损失。在本文，笔者就对如何预防以及治疗猪口蹄疫、流感猪病等疾病提出自己的一些看法。

A Review on 2009 Influenza A Virus

[Objective] The paper was to introduce the research progress of 2009 influenza A virus. [Method] 2009 influenza A virus was introduced from the aspects of classification and host, virology, molecular characteristics and vaccine. [Result] A novel influenza A/H1N1 virus emerged in early April 2009 quickly spread worldwide through human-to-human transmission. The virus contained a group of novel gene segments, the nearest known precursor was the virus found in swine. The virus appeared to retain the potential to infect swine again and thus continued reassort with swine viruses. All registered 2009 influenza A vaccines were tested for safety and immunogenicity in clinical trials on human volunteers, and all vaccines were found to be safe, single dose of vaccine could cause protective antibody responses. [Conclusion] The paper provided basis for further study on 2009 influenza A virus.

Molecular Characterization of Avian-like H1N1 Swine Influenza A Viruses Isolated in Eastern China, 2011

Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide： H1N1, H3N2, and H1N2. European avian-Hke H1N1 viruses, which were initially detected in European pig populations in 1979, have been circulating in pigs in eastern China since 2007. In this study, six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China. Based on whole genome sequencing, molecular characteristics of two isolates were determined. Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations, especially similar to those found in China. Four potential glycosylation sites were observed at positions 13, 26, 198, 277 in the HA1 proteins of the two isolates. Due to the presence of a stop codon at codon 12, the isolates contained truncated PB1-F2 proteins. In this study, the isolates contained 591Q, 627E and 701N in the polymerase subunit PB2, which had been shown to be determinants of virulence and host adaptation. The isolates also had a D rather than E at position 92 of the NS1, a marker of mammalian adaptation. Both isolates contained the GPKV motif at the PDZ ligand domain of the 3＇ end of the NS1, a characteristic marker of the European avian-like swine viruses since about 1999, which is distinct from those of avian, human and classical swine viruses. The M2 proteins of the isolates have the mutation （S31N）, a characteristic marker of the European avian-like swine viruses since about 1987, which may confer resistance to amantadine and rimantadine antivirals. Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs, and raise more concerns about the occurrence of cross-species transmission events.

Association of swine influenza H1N1 pandemic virus(SIV-H1N1p) with porcine respiratory disease complex in sows from commercial pig farms in Colombia

Porcine respiratory disease complex （PRDC） is a serious health problem that mainly affects growing and finishing pigs. PRDC is caused by a combination of viral and bacterial agents, such as porcine reproductive and respiratory syndrome virus （PRRSV）, swine influenza virus （SIV）, Mycoplasma hyopneumoniae （Myh）, Actinobacillus pleuropneumoniae （APP）, Pasteurella multocida and Porcine circovirus 2 （PCV2）. To characterize the specific role of swine influenza virus in PRDC presentation in Colombia, 11 farms from three major production regions in Colombia were examined in this study. Nasal swabs, bronchial lavage and lung tissue samples were obtained from animals displaying symptoms compatible with SIV. Isolation of SIV was performed in 9-day embryonated chicken eggs or Madin-Darby Canine Kidney （MDCK） cells. Positive isolates, identified via the hemagglutination inhibition test, were further analyzed using PCR. Overall, 7 of the 11 farms were positive for SIV. Notably, sequencing of the gene encoding the hemagglutinin （HA） protein led to grouping of strains into circulating viruses identified during the human outbreak of 2009, classified as pandemic H1N1-2009. Serum samples from 198 gilts and multiparous sows between 2008 and 2009 were obtained to determine antibody presence of APP, Myh, PCV2 and PRRSV in both SIV-H1Nlp-negative and -positive farms, but higher levels were recorded for SIV- HI Nlp-positive farms. Odds ratio （OR） and P values revealed statistically significant differences （p〈0.05） in PRDC presentation in gilts and multiparous sows of farms positive for SIV-HINlp. Our findings indicate that positive farms have increased risk of PRDC presentation, in particular, PCV2, APP and Myh.

Close Relationship between the 2009 H1N1 Virus and South Dakota AIV Strains

Although previous publications suggest the 2009 pandemic influenza A (H1N1) virus was reassorted from swine viruses of North America and Eurasia,the immediate ancestry still remains elusive due to the big evolutionary distance between the 2009 H1N1 virus and the previously isolated strains. Since the unveiling of the 2009 H1N1 influenza,great deal of interest has been drawn to influenza,consequently a large number of influenza virus sequences have been deposited into the public sequence databases. Blast analysis demonstrated that the recently submitted 2007 South Dakota avian influenza virus strains and other North American avian strains contained genetic segments very closely related to the 2009 H1N1 virus,which suggests these avian influenza viruses are very close relatives of the 2009 H1N1 virus. Phylogenetic analyses also indicate that the 2009 H1N1 viruses are associated with both avian and swine influenza viruses circulating in North America. Since the migrating wild birds are preferable to pigs as the carrier to spread the influenza viruses across vast distances,it is very likely that birds played an important role in the inter-continental evolution of the 2009 H1N1 virus. It is essential to understand the evolutionary route of the emerging influenza virus in order to find a way to prevent further emerging cases. This study suggests the close relationship between 2009 pandemic virus and the North America avian viruses and underscores enhanced surveillance of influenza in birds for understanding the evolution of the 2009 pandemic influenza.