Hepatitis E virus in swine and effluent samples from slaughterhouses in Brazil

Hepatitis E is an infectious disease which virus (HEV) is highly disseminated in swine herd populations. Sporadic acute human hepatitis E cases have been associated to genotype 3 and 4 strains of HEV also reported in swine populations of endemic and non-endemic areas. With the aim to evaluate the incidence of animals with current infection of HEV, 115 bile samples were collected from three slaughterhouses under inspection by Animal Sanitary Protection Agency of Rio de Janeiro, Brazil. In parallel, effluent samples were collected from six sewage pipe exit sites of two slaughterhouses. HEV RNA was detected in 11 out of 115 (9.6%) bile samples collected and three waste samples from one slaughterhouse. Viral loads observed for bile samples varied from 10(1)-10(5) genome copies/mL and for effluent samples mean load was 10(2) genome copies/mL. Sequencing and phylogenetic analysis classified samples within genotype 3 subtype 3b closely related to the sample obtained from the first reported autochthonous human case and samples from swine of commercial herds in Brazil. Our data demonstrates that although most animals achieve slaughter age (around 20 weeks old) already immune to HEV, a significant number of animals are with current infection at commercial age. Further studies should be addressed to consider risk analysis and possible evaluation of inspection regulations considering food safety measures regarding hepatitis E zoonotic aspect in Brazil.     

江西部分地区猪粪便戊型肝炎病毒核酸检测及序列分析

采集江西省A猪场2～3月龄猪粪便40份,B猪场2～3月龄猪粪便40份,利用反转录套式聚合酶链方法(RT-nPCR),检测戊型肝炎病毒(hepatitis E virus,HEV)RNA,结果表明,A猪场7份样品为阳性,阳性率17.5%.B猪场10份样品为阳性,阳性率25.0%.总阳性率21.3%.对4份PCR扩增阳性产物进行纯化并测序,利用生物学软件进行序列分析和进化树绘制,4个分离株ORF2 348 bp同源性为92.1%～97.5%,为同一基因型,与HEV1、HEV2、HEV3同源性分别为70.7%～77.4%、72.5%~75.7%和71.6%～76.8%,与HEV4型的同源性79.2%～83.9%.4个分离株与HEV4型的代表株T1在同一分支上,属基因4型.与中国大陆6株猪源HEV比较,同源性为79.0%～87.3%,提示中国大陆猪源HEV的基因型比较一致,同属HEV 4型.     

广东省部分地区规模化猪场猪流感病毒感染的血清学调查与分析

为了解广东省规模化猪场猪流感病毒(SIV)感染情况,本研究采用ELISA方法和血凝抑制试验(HI),对2011年～2012年采集的1 050份血清样品进行SIV血清学检测.两种检测方法结果显示1 050份血清样品中SIV抗体阳性率分别为50.4％(ELISA)和50.2％(HI).其中珠三角地区和粤东地区的感染率高于粤西地区.SIV亚型调查结果显示该地区流行的SIV主要为H1和H3亚型,抗体阳性率分别为39.2％和18.2％(ELISA).部分猪场存在H9亚型SIV抗体.部分猪群中同时存在H1和H3两种亚型SIV抗体,表明猪群中存在不同亚型SIV混合感染.本研究为广东省猪流感的预防提供参考依据.     

Hepatitis E virus infection in swine workers: A meta‐analysis

Hepatitis E virus (HEV) infects both humans and animals. Swine has been confirmed to be the principal natural reservoir, which raises a concern that HEV infection would be substantially increasing among swine workers. The present study calculated the pooled prevalence of IgG antibodies against HEV among swine workers and the general population in previous cross‐sectional studies. We conducted a meta‐analysis comparing the prevalence of HEV infection between swine workers and the general population, including local residents, blood donors and non‐swine workers. Through searches in three databases (PubMed and OVID in English, and CNKI in Chinese) and after study selection, a total of 32 studies from 16 countries (from 1999 through 2018) were included in the meta‐analysis. A random‐effect model was employed in the study; an I ² statistic assessed heterogeneity, and the Egger's test detected publication bias. The comparative prevalence of anti‐HEV IgG was pooled from the studies. Compared to the general population, the prevalence ratio (PR) for swine workers was estimated to be 1.52 (95% CI 1.38–1.76) with the I ² being 71%. No publication bias was detected (p = 0.40). A subgroup analysis further indicated increased prevalence of anti‐HEV IgG in the swine workers in Asia (PR = 1.49, 95% CI: 1.35–1.64), in Europe (PR = 1.93, 95% CI: 1.49–2.50) and in all five swine‐related occupations, including swine farmers, butchers, meat processors, pork retailers and veterinarians (PR ranged between 1.19 and 1.75). In summary, swine workers have a relatively higher prevalence of past HEV infection, and this finding is true across swine‐related occupations, which confirms zoonotic transmission between swine and swine workers.     

Molecular characterization of Japanese encephalitis virus strains prevalent in Chinese swine herds

Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia and domestic pigs serve as the amplifying hosts. In the present study, the full genomic sequences of two JEV strains (HEN0701 and SH0601) isolated from pigs in China were determined and compared with other 12 JEV strains deposited in GenBank. These two strains had an 88.8% nucleotide sequence similarity and 97.9% deduced amino acid sequence homology. HEN0701 had high nucleotide sequence and high amino acid sequence identity with genotype I (GI) strains, while SH0601 had high nucleotide sequence and high amino acid sequence identity with GIII strains at both the gene and full genome levels. Further phylogenetic analysis showed that HEN0701 belonged to the JEV GI group and SH0601 was classified as a GIII strain. Analysis of codon usage showed there were a few differences between the GI and GIII strains in nucleotide composition and codon usage for the open reading frames.     

Psychodemographic profile of stockpeople working on independent and integrated swine breeding farms in Quebec.

As a part of a larger study, the psychodemographic profile of Quebec pig stockpeople was described based on a sample of 48 persons working on independent farms randomly selected in the Richelieu-Saint-Hyacinthe region, and on a convenience sample of 38 others employed by 5 organizations of integrated swine production chosen among the largest ones in Québec. The 2 groups of stockpeople were described separately because of the differences between the 2 types of production. Demographic data (age, sex, level of education, training and experience in swine production, seniority on the farm) were obtained through a face-to-face interview. The personality profile was assessed using a standard personality test (French translation of the Sixteen Personality Factor Questionnaire). Both the stockpersons on independent farms and those employed by the organizations were more reserved, emotionally stable, serious, conscientious, unsentimental, controlled, introverted, and less anxious than the average person in the general population. However, multivariate analyses revealed some differences between these two groups of stock-persons (P = 0.021) as well as between the employees of the different organizations (P = 0.0038). These differences in personality profiles may reflect differences in working conditions, particularly regarding the human relationships, and in corporate cultures of the organizations.     

云南省部分猪场猪戊型肝炎的流行情况调查

为了解云南省猪群戊型肝炎感染情况,从云南省8个猪场采集166份新鲜猪粪便样品,用套式RT-PCR技术对戊型肝炎病毒(HEV)核酸进行检测,结果 21份样品阳性,阳性率为12.7%,感染率较高。通过PCR产物片段的测序分析,去除重复序列后得到11株基因序列。同源性分析结果表明,这11株毒株序列与选定的Gen Bank中基因1型、2型、3型和4型参考序列的核苷酸序列同源性分别为85.6%~87.8%,85.6%~87.8%,85.6%~95.6%和92.8%~98.9%,说明这些株毒株属于基因4型,与中国其他地区分离的毒株同源性最高,证实HEV的流行具有地理分布的特征。     

Hepatitis E virus chronic infection of swine co-infected with Porcine Reproductive and Respiratory Syndrome Virus

In developed countries, most of hepatitis E human cases are of zoonotic origin. Swine is a major hepatitis E virus (HEV) reservoir and foodborne transmissions after pork product consumption have been described. The risk for HEV-containing pig livers at slaughter time is related to the age at infection and to the virus shedding duration. Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is a virus that impairs the immune response; it is highly prevalent in pig production areas and suspected to influence HEV infection dynamics. The impact of PRRSV on the features of HEV infections was studied through an experimental HEV/PRRSV co-infection of specific-pathogen-free (SPF) pigs. The follow-up of the co-infected animals showed that HEV shedding was delayed by a factor of 1.9 in co-infected pigs compared to HEV-only infected pigs and specific immune response was delayed by a factor of 1.6. HEV shedding was significantly increased with co-infection and dramatically extended (48.6 versus 9.7 days for HEV only). The long-term HEV shedding was significantly correlated with the delayed humoral response in co-infected pigs. Direct transmission rate was estimated to be 4.7 times higher in case of co-infection than in HEV only infected pigs (0.70 and 0.15 per day respectively). HEV infection susceptibility was increased by a factor of 3.3, showing the major impact of PRRSV infection on HEV dynamics. Finally, HEV/PRRSV co-infection – frequently observed in pig herds – may lead to chronic HEV infection which may dramatically increase the risk of pig livers containing HEV at slaughter time.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0207-y) contains supplementary material, which is available to authorized users.     

猪戊型肝炎病毒大庆株DQ1全基因序列分析

本试验采用RT．-PCR的方法对戊型肝炎病毒大庆株（DQ1HEV株）的全基因进行分片段扩增，并对其两个末端采用末端快速扩增法（RACE）进行扩增、克隆，测序。与已报道的人的14株HEV的4个基因型的核苷酸和氨基酸进行比较，与IV型HEV的同源性最高。ORF1区与IV型HEV核苷酸的同源性为82．6％～83．6％．氨基酸同源性为93．5％，ORF2区与IV型HEV核苷酸的同源性为87．0％～88.4％，氨基酸同源性为95．8％～97．4％。ORF3区与IV型HEV核苷酸的同源性为94．4％～96．5％，氨基酸同源性为90.3％～96．5％。其结果表明DQ1 HEV株为IV型HEv。     

H9N2亚型猪流感病毒对小鼠的致病性及其分子特性研究

本实验从河北地区疑似流感发病猪体内分离到一株病毒,经鉴定为H9N2亚型猪流感(SIV)病毒.将该分离株经滴鼻、点眼途径感染小鼠,观察临床症状和病理变化,同时对血凝素(HA)、神经氨酸酶(NA)、核蛋白(NP)和基质蛋白基因(M)进行克隆和序列测定,与GenBank中登录的相关序列进行比对并绘制系统发育进化树.致病性结果显示:感染小鼠出现精神不振,体重下降,并引起以弥漫性肺泡损伤为主的临床症状和病理变化.序列分析结果显示:该分离株与禽流感病毒(AW) A/chicken/Hebei/4/2008 (H9N2)(简称CK/HB/4/08)参考株的HA、NA、NP和M基因的核苷酸序列和推导的氨基酸序列的同源性最高.HA蛋白的裂解位点序列为PARSSR↓GLF,属于低致病性流感病毒的裂解位点.HA、NP、NA和M基因的遗传进化分析均显示该分离株与AIV的CK/HB/4/08株位于同一分支,具有较近的亲缘关系;由此推测该分离株可能是由CK/HB/4/08演化而来,并在跨物种传播的过程中发生了部分变异.     

Serological evidence of pig-to-human influenza virus transmission on Thai swine farms

We investigated influenza interspecies transmission in two commercial swine farms in Thailand. Sera from swine-exposed workers (n=78), age-matched non-swine-exposed healthy people (n=60) and swine populations in both farms (n=85) were studied. Hemagglutination-inhibition (HI) assay was performed on Thai swine H1 viruses (swH1N1 and swH1N2) isolated from both farms. Thai human H1N1 (huH1N1) and pandemic H1N1 2009 (pH1N1) were also used as test antigens. The hemagglutinin (HA) 1 genes of swH1N1 and swH1N2 viruses were sequenced and shown to be genetically distinct from the Thai huH1N1 and pH1N1 viruses. Evidence of pig-to-human influenza virus transmission was found in farm workers with increased odds of elevated antibody titers to both swH1N1 (OR 42.63, 95% CI, 14.65-124) and swH1N2 (OR 58, 95% CI, 13.12-256.3) viruses. No evidence of human-to-pig influenza virus transmission was detected in this study.     

猪场看不见的浪费

猪场的浪费现象太多了，如白天着灯是浪费，饲料洒在地上是浪费，长流水是浪费等，这些都是能看见的浪费，我今天谈一些看不见的但却很严重的浪费。     

杭州地区规模化猪场猪伪狂犬病和猪繁殖与呼吸综合征的血清学调查

为配合杭州地区无规定疫病区的建设,查清本地区猪伪狂犬病(PR)、猪繁殖与呼吸综合征(P RRS)现状,我站采用ELISA方法对本地区主要规模场进行了PR和PRRS普查.     

广西猪伪狂犬病毒感染状况调查报告

为了解广西猪伪狂犬病毒的感染状况,应用PCR技术对来自广西46个种猪场的1940份公猪精液进行了猪伪狂犬病毒(PRV)的检测,阳性率为0;同时对广西25个已使用猪伪狂犬病病毒gE基因缺失疫苗猪场的1455份送检血清,采用了猪伪狂犬病基因缺失鉴别ELISA方法进行了血清学抗体监测,结果检出猪伪狂犬gE抗体阳性11份,阳性率为0.76%。结果表明,广西猪群中存在猪伪狂犬病野毒感染,但感染率较低。     

Outbreaks in Quebec pig farms of respiratory and reproductive problems associated with encephalomyocarditis virus.

Encephalomyocarditis virus (EMCV) was isolated from tissues of aborted fetuses and weaned and suckling piglets from 4 different pig farms in Quebec. The farms were experiencing reproductive failure in sows of different parities concomitant to respiratory problems in suckling and postweaning piglets. At necropsy, gross lesions were confined to the lung and consisted of pulmonary congestion and edema of various degrees. Lesions of multifocal interstitial to proliferative pneumonia were found in the lungs of these piglets. Bacteriologic examination of various tissues from necropsied pigs yielded no pathogens in most cases. No significant antibody titers against 3 swine viruses (transmissible gastroenteritis virus, porcine parvovirus, and swine influenza virus) and two bovine viruses (bovine viral diarrhea and infectious bovine rhinotracheitis viruses) were detected in the sera of convalescent pigs. The Quebec EMCV isolates were antigenically related to the reference ATCC-VR129 strain of EMCV, as demonstrated by indirect immunofluorescence, serum neutralization (SN), and Western immunoblotting. However, one of the Quebec isolates could be distinguish by SN. EMCV-specific SN antibody titers up to 1:12,800 were detected in thoracic and ascitis fluids of aborted fetuses and in sera of convalescent pigs. A possible pneumotropic EMCV variant in swine may exist.     

山东省规模化猪场PRRSV NSP2变异株的感染情况调查

为了解山东省规模化猪场猪繁殖与呼吸障碍综合征病毒(PRRSV) NSP2变异株的感染情况,2010～2011年本研究从山东省未免猪繁殖与呼吸障碍综合征(PRRS)疫苗猪场、免疫进口PRRS弱毒苗猪场和免疫国产PRRS弱毒苗猪场选择20个临床表观健康的规模化猪场,采集830份血清,利用RT-PCR方法对其进行PRRSV NSP2变异株病原学检测.结果表明山东省规模化猪场普遍存在PRRSV NSP2变异株感染,而且临床表观健康的未免疫PRRS疫苗猪场、免疫进口PRRS弱毒苗猪场及免疫国产PRRS弱毒苗猪场中PRRSV NSP2变异株的检出率由高到低,同一猪群中存在PRRSV NSP2变异株野毒和疫苗毒.     

猪流感病毒分子生物学研究进展

猪流感（Swine influenza，SI）是由猪流感病毒（SIV）引起的一种急性高度接触传染性的群发性呼吸道疾病，其特征为突发咳嗽、呼吸困难、发热、衰竭及迅速康复，猪不分年龄、品种和性别均能感染，是规模化猪场普遍存在难以根治的群发性疾病之一。     

猪源多重耐药大肠杆菌中整合子的检测

为了解猪源多重耐药大肠杆菌中整合子的流行状况和分子特性,分析整合子在细菌多重耐药中的作用,采用PCR方法检测75株多重耐药大肠杆菌中整合酶基因和整合子基因盒。结果显示,猪源大肠杆菌Ⅰ型整合子流行普遍,75株猪源大肠杆菌中检出Ⅰ类整合子56株,检出率为74.7%;检出Ⅱ类整合子4株,检出率5.3%;未检出Ⅲ类整合子。共检出5种Ⅰ型整合子,各种Ⅰ型整合子整合不同种类、不同数目的耐药基因盒。这表明Ⅰ型整合子对细菌多重抗药性的产生和传播起着重要作用,整合子是介导细菌多重耐药性的重要分子机制。