Seroprevalences of classical swine fever virus and porcine reproductive and respiratory syndrome virus in pigs in Hunan Province, China

Abstract Background: Classical swine fever (CSF) and porcine reproductive and respiratory syndrome (PRRS) are responsible for major economic losses and represent a threat to the swine industry worldwide. Routine surveillance serology for CSF and PRRS will be critical to maintain the health status of sow farms in Hunan Province, which is one of the top pig production provinces in China.The objective of our study was to investigate the seroprevalence of CSF virus (CSFV) and PRRS virus (PRRSV) in Hunan Province from 2017 to 2019 using ELISA. The cohort pig serum samples were collected from vaccinated and unvaccinated sow farms in eight cities in Hunan Province. Results: CSFV and PRRSV seropositivity showed significant differences among parts of Hunan Province in China. Interestingly, our findings show that the level of CSFV antibody in piglet sera decreases gradually with increasing piglet age, whereas PRRSV-specific antibodies may appear in various growth stages in unvaccinated animals. Meanwhile, the average rate of CSFV antibody seropositivity was 82.2%, while the rate of PRRSV antibody seropositivity was slightly higher (84.4%) in the immunized group.Conclusions: The results from this study suggest that a serological investigation of these two major infectious diseases (CSF and PRRS) among pigs at various growth stages will provide a basis for the further development of more effective prevention and control measures.

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Seroprevalences of Classical Swine Fever Virus and Porcine Reproductive and Respiratory Syndrome Virus in Pigs in Hunan Province, China

10.21203/rs.3.rs-41387/v1 ◽

2020 ◽

Author(s):

Haoyang Yu ◽

Luhua Zhang ◽

Yunfeng Cai ◽

Tao Peng ◽

Lei Liu ◽

...

Keyword(s):

Infectious Diseases ◽

Classical Swine Fever Virus ◽

Classical Swine Fever ◽

Fever Virus ◽

Central China ◽

Hunan Province ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Growth Stages

Abstract Background: Several infectious diseases including classical swine fever (CSF) and porcine reproductive and respiratory syndrome (PRRS) are responsible for major economic losses and represent a threat to the swine industry worldwide. Hunan is a province in south-central China, serological statistics will have certain effect on local breeding industry.The present study investigated the seroprevalences of classical swine fever virus (CSFV) and porcine reproductive and respiratory syndrome virus (PRRSV) in pigs from eight cities of Hunan province from 2017 to 2019. The samples were divided into two groups based on whether the hosts were immunized or not, and analysed by enzyme-linked immunosorbent assay (ELISA).Results: The seropositivity of CSFV and PRRSV between different parts of Hunan province in China was statistically significant. In unvaccinated group, our findings showed CSFV antibody in piglets' sera decreases gradually with increase of piglets' age whereas PRRSV-specific antibodies may appear in various growth stages. In immunized group, the average seropositive rate of CSFV antibody was 82.2%, while the rate of PRRSV antibody was relatively higher (84.4%).Conclusions: Results from this study suggested that a serological investigation on these two major infectious diseases (CSF and PRRS) among various growth stages of pigs will provide a basis for further development of more effective preventions and control measures.

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Major Vault Protein Inhibits Porcine Reproductive and Respiratory Syndrome Virus Infection in CRL2843CD163 Cell Lines and Primary Porcine Alveolar Macrophages

Viruses ◽

10.3390/v13112267 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2267

Author(s):

Xiaoping Wu ◽

Junyang Fang ◽

Qiuping Huang ◽

Xu Chen ◽

Zhongyi Guo ◽

...

Keyword(s):

Cell Lines ◽

Alveolar Macrophages ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Major Vault Protein ◽

Swine Industry ◽

Effective Prevention ◽

Viral Infectious Disease ◽

Sirna Knockdown

Porcine reproductive and respiratory syndrome (PRRS), a significant viral infectious disease that commonly occurs among farmed pigs, leads to considerable economic losses to the swine industry worldwide. Major vault protein (MVP) is a host factor that induces type Ⅰ interferon (IFN) production. In this study, we evaluated the effect of MVP on PRRSV infection in CRL2843CD163 cell lines and porcine alveolar macrophages (PAMs). Our results showed that MVP expression was downregulated by PRRSV infection. Adenoviral overexpression of MVP inhibited PRRSV replication, whereas the siRNA knockdown of MVP promoted PRRSV replication. In addition, MVP knockdown has an adverse effect on the inhibitive role of MVP overexpression on PRRSV replication. Moreover, MVP could induce the expression of type Ⅰ IFNs and IFN-stimulated gene 15 (ISG15) in PRRSV-infected PAMs. Based on these results, MVP may be a potential molecular target of drugs for the effective prevention and treatment of PRRSV infection.

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Prevalence of Porcine Pseudorabies Virus and Its Coinfection Rate in Heilongjiang Province in China from 2013 to 2018

10.21203/rs.2.12447/v1 ◽

2019 ◽

Author(s):

Han Zhou ◽

Yan Pan ◽

Mengda Liu ◽

Zifeng Han

Keyword(s):

Pseudorabies Virus ◽

Classical Swine Fever ◽

Porcine Circovirus ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Heilongjiang Province ◽

Serum Samples ◽

Tissue Samples ◽

Wide Range ◽

Pig Farms

Abstract Background Pseudorabies (PR) is a highly contagious disease affecting a wide range of animals worldwide, which causes great annual economic losses in China. In this study, a total number of 18815 serum samples and 1589 tissue samples were tested by ELISA and PCR, which were collected from 311 intensive pig farms (≥350 sows) located in eight cities in Heilongjiang province. Results Overall, 16.3% and 84.5% serum samples were positive for gE- and gB-specified ELISA, respectively. 17.8% of tissue samples were shown as PCR positive for PRV. The co-infection rates of PRV with porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), and classical swine fever virus (CSFV) were measured. The rate of PRV co-infected with PRRSV was 36.0% followed by 12.9% with PCV2 and 1.8% with CSFV, respectively. Conclusions These results clearly demonstrate PRV prevalence and its coinfection rate in Heilongjiang province indicating high PR endemic in pig farms in this region. This study provides data for further epidemiological investigations and a reference for developing PRV control strategies in this region and in China.

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Serodynamic Analysis of the Piglets Born from Sows Vaccinated with Modified Live Vaccine or E2 Subunit Vaccine for Classical Swine Fever

Pathogens ◽

10.3390/pathogens9060427 ◽

2020 ◽

Vol 9 (6) ◽

pp. 427 ◽

Cited By ~ 2

Author(s):

Yi-Chia Li ◽

Ming-Tang Chiou ◽

Chao-Nan Lin

Keyword(s):

Detection Rate ◽

Time Window ◽

Classical Swine Fever ◽

Significant Negative Correlation ◽

Live Vaccine ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Serum Samples ◽

Significant Difference ◽

Modified Live Vaccine

Classical swine fever (CSF) caused by the CSF virus (CSFV) is one of the most important swine diseases, resulting in huge economic losses to the pig industry worldwide. Systematic vaccination is one of the most effective strategies for the prevention and control of this disease. Two main CSFV vaccines, the modified live vaccine (MLV) and the subunit E2 vaccine, are recommended. In Taiwan, CSF cases have not been reported since 2006, although systemic vaccination has been practiced for 70 years. Here, we examined the sero-dynamics of the piglets born from sows that received either the CSFV MLV or the E2 vaccine and investigated in the field the correlation between the porcine reproductive and respiratory syndrome virus (PRRSV) loads and levels of CSFV antibody. A total of 1398 serum samples from 42 PRRSV-positive farms were evaluated to determine the PRRSV loads by real-time PCR and to detect CSFV antibody levels by commercial ELISA. Upon comparing the two sow vaccination protocols (CSFV MLV vaccination at 4 weeks post-farrowing versus E2 vaccination at 4–5 weeks pre-farrowing), the lowest levels of CSFV antibody were found in piglets at 5–8 and 9–12 weeks of age for the MLV and E2 groups, respectively. Meanwhile, the appropriate time window for CSFV vaccination of offspring was at 5–8 and 9–12 weeks of age in the MLV and E2 groups, respectively. There was a very highly significant negative correlation between the PRRSV load and the level of CSFV antibody in the CSFV MLV vaccination group (P < 0.0001). The PRRSV detection rate in the pigs from the MLV group (27.78%) was significantly higher than that in pigs from the E2 group (21.32%) (P = 0.011). In addition, there was a significant difference (P = 0.019) in the PRRSV detection rate at 5–8 weeks of age between the MLV (42.15%) and E2 groups (29.79%). Our findings indicate that the vaccination of CSFV MLV in piglets during the PRRSV susceptibility period at 5–8 weeks of age may be overloading the piglet’s immune system and should be a critical concern for industrial pork production in the field.

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Efficiency Comparison of a Novel E2 Subunit Vaccine and a Classic C-Strain Vaccine against Classical Swine Fever

Veterinary Sciences ◽

10.3390/vetsci8080148 ◽

2021 ◽

Vol 8 (8) ◽

pp. 148

Author(s):

Pei Zhou ◽

Junming Huang ◽

Yanchao Li ◽

Hui Chen ◽

Yidan Wu ◽

...

Keyword(s):

Subunit Vaccine ◽

Classical Swine Fever ◽

Antibody Responses ◽

Control Measures ◽

Economic Losses ◽

Swine Industry ◽

Field Virus ◽

Strain Vaccine ◽

Efficiency Comparison ◽

The Government

Classical swine fever (CSF) is one of the most important viral diseases in swine, causing severe economic losses in the swine industry. In China, CSF is one of the key diseases that needs to be controlled; the government has implemented control measures, and vaccination with C-strain vaccines (C-vacs) has been compulsory since the 1950s. C-vacs do not allow the differentiation of field virus-infected and vaccinated animals (DIVA). In 2012, China proposed a goal of eradicating CSF. Additionally, a baculovirus-expressed E2 subunit vaccine (E2-vac) was licensed in 2018. However, the C-vac and E2-vac characteristics have not been compared. Here, we demonstrate that both the C-vac and E2-vac provide complete protection against CSF in pigs. The E2-vac allows DIVA, and the E2 antibody responses of stimulated pigs are developed earlier and are stronger than the C-vac antibody responses. Therefore, the E2-vac is a new candidate licensed vaccine to completely eradicate CSF on pig farms.

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Surveillance results of communicable swine diseases in breeding pig farms near Ulaanbaatar city

Mongolian Journal of Agricultural Sciences ◽

10.5564/mjas.v29i1.1316 ◽

2020 ◽

Vol 29 (1) ◽

pp. 56-63

Author(s):

Bayarmaa Sukhbaatar ◽

Amartuvshin Tsolmon ◽

Shurenchimeg Badamjav ◽

Gantumur Tsedee ◽

Erdenebat Bulgan ◽

...

Keyword(s):

Infectious Diseases ◽

African Swine Fever ◽

Classical Swine Fever ◽

Elisa Test ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Serum Samples ◽

Prophylactic Measures ◽

Pig Farms ◽

Swine Diseases

We have done laboratory-based analyses of highly contagious and infectious swine diseases commonly occurring in household and pig farms on 200 swine serum samples collected from Bayanzurkh, Songinokhairkhan, Nalaikh, Khan-Uul district of Ulaanbaatar city, to establish the rate of infection, to gather information on farming and bio-security, to further detect this infectious diseases, for the purpose of risk assessment and preventive research. According to ELISA test results Classical swine fever 27 (13.5%), Parvovirus 50 (25%), Influenza 16 (8%), Circovirus 112 (56%) samples had shown positive results. Presence of classical swine fever antibody in 27/200 samples are reaction of vaccine immunization. Also antibody presence of Swine parvovirus, Influenza, circovirus in samples indicates necessity of make it clear that whether symptomless cases around farms. But antibody absence of porcine food and mouth disease, porcine reproductive and respiratory syndrome virus, swine mycoplasmosis transmissible gastro-enteritis, coronovirus, leptospirosis, brucellosis indicates such disease free in farms. Antibody absence of African swine fever done by surveillance this time shows no further infection however it was occurred in Mongolia early in 2019. Fundamental surveying is a key tool for monitoring health status of pig farm and formulating eradication program for swine infectious diseases as well as help farmers prevent economic losses by implementing prophylactic measures against sudden cases of such diseases. Thus we suggest that above mentioned surveillance study need to be continued as a tool for monitoring because of it is importance of keep pig farmers sustainable, furthermore crucial for nation`s economy. Улаанбаатар хотын ойролцоо үржүүлж буй гахайд зонхилон тохиолдох халдварт өвчнүүдийг тандан судалсан дүн Улаанбаатар хотын Баянзүрх, Налайх, Сонгинохайрхан, Хан-Уул зэрэг 4 дүүргийн өрхийн болон аж ахуйн гахайд зонхилон тохиолддог гоц болон халдварт өвчнүүдийн лабораторид суурилсан шинжилгээг хийх, халдварлалтын түвшинг тогтоох, аж ахуй эрхлэлт, биоаюулгүй байдлын талаар мэдээлэл цуглуулах, цаашид халдварт өвчнийг эрт илрүүлэх, эрсдэлийг үнэлэх, урьдчилан сэргийлэх судалгааны ажлын зорилгын хүрээнд нийт 200 дээжинд эсрэгбием илрүүлэх ЭЛИЗА урвалаар шинжилгээг хийхэд гахайн сонгомол мялзан 27 (13.5%), парвовирус 50 (25%), томуу 16 (8%), цирковирус 112 (56%) дээж эерэг дүн үзүүлэв. Гахайн сонгомол мялзан өвчний эсрэгбием (27/200) илэрсэн нь урьдчилан сэргийлэх зорилгоор тарьсан вакцины урвал юм. Гахайн парвовирус, гахайн томуу, гахайн цирковирус зэрэг өвчний вирусын эсрэгбием илэрч байгаа нь ил шинж тэмдэггүй, халдварын тархалт байгаа эсэхийг баталгаажуулах шаардлагатайг харуулж байна. Харин гахайн шүлхий, микоплазм, гахайн үржил, амьсгалын замын хам шинж, гахайн ходоод гэдэсний замын халдварт үрэвсэл, коронавирус, лептоспироз, бруцеллёз зэрэг өвчний эсрэгбием илрээгүй нь халдваргүйг харуулж байна. Гахайн африкийн мялзан өвчин Монгол оронд 2019 оны эхээр гарч байсан ч энэ удаагийн тандалтаар эсрэгбием илрээгүй нь өвчлөл дахиж гараагүй болохыг харуулж байна. Тандан судалгаа нь гахайн эрүүл мэндийг хянах, эрүүлжүүлэх хөтөлбөрийг боловсруулах гахайн аж ахуйд тохиолдох эдийн засгийн болзошгүй эрсдэлээс урьдчилан хянахад чухал ач холбогдолтой. Тиймээс энэхүү суурь судалгааг жил бүр тогтмол хийх нь гахайн аж ахуйг тогтвортой байлгах төдийгүй улс орны эдийн засагт чухал ач холбогдолтой тул гахайн эрүүл мэндийг хянах зорилгоор үргэлжлүүлэн хийж байх шаардлагатай байна. Түлхүүр үг: Гахайн халдварт өвчнүүд, ЭЛИЗА, тандан судалгаа, эсрэгбием

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Seroprevalence of porcine reproductive and respiratory syndrome virus on swine farms in a tropical country of the Middle Americas: the case of Costa Rica

Tropical Animal Health and Production ◽

10.1007/s11250-021-02799-9 ◽

2021 ◽

Vol 53 (4) ◽

Author(s):

Ronald Meléndez ◽

Mónica Guzmán ◽

Carlos Jiménez ◽

Marta Piche ◽

Emily Jiménez ◽

...

Keyword(s):

Costa Rica ◽

Pilot Study ◽

Costa Rican ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Second Phase ◽

Serum Samples ◽

Swine Industry ◽

Tropical Country ◽

Cross Sectional

AbstractPorcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses to the swine industry worldwide. Little is known regarding the epidemiology of this infection in tropical countries. To address this problem in Costa Rica, a seroepidemiological study was carried out in two phases. In the first phase, a pilot study was conducted in nine farms with the clinical diagnosis of PRRSV. In total, 265 pig serum samples were collected from animals ranging in age from 1 to 15 weeks of age. This study aimed to establish the duration of maternal immunity in piglets, to identify the period of viremia, and to determine when seroconversion occurs. In the second phase, a cross-sectional serology study was performed on a representative sample of the Costa Rican national herds in the second phase. The twenty-five selected farms represent all provinces and were classified according to herd size (100 to 2000 sows). In each farm, pigs aged 8, 10, and 12 weeks were sampled, as well as gilts based on the pilot study. In total 1281 pigs were sampled across all 25 farms. The aim of the cross-sectional study was to quantify the seroprevalence of PRRSV in Costa Rican pig farms and to describe its geographical distribution in this tropical country. The prevalence of positive farms was 44% (11/25), and these farms were located in six of the seven provinces of Costa Rica. Overall, 58% (344/596) of the pigs were seropositive to PRRSV. The age of the pigs and the ecozone where farms were located were significantly related with PRRSV seroprevalence in animals and herds, respectively.

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The Function of the PRRSV–Host Interactions and Their Effects on Viral Replication and Propagation in Antiviral Strategies

Vaccines ◽

10.3390/vaccines9040364 ◽

2021 ◽

Vol 9 (4) ◽

pp. 364

Author(s):

Jun Ma ◽

Lulu Ma ◽

Meiting Yang ◽

Wei Wu ◽

Wenhai Feng ◽

...

Keyword(s):

Immune Response ◽

Molecular Mechanisms ◽

Immune Escape ◽

Rna Virus ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Swine Industry ◽

Live Virus ◽

Virus Challenge ◽

Host Interactions

Porcine reproductive and respiratory syndrome virus (PRRSV) affects the global swine industry and causes disastrous economic losses each year. The genome of PRRSV is an enveloped single-stranded positive-sense RNA of approximately 15 kb. The PRRSV replicates primarily in alveolar macrophages of pig lungs and lymphatic organs and causes reproductive problems in sows and respiratory symptoms in piglets. To date, studies on how PRRSV survives in the host, the host immune response against viral infections, and pathogenesis, have been reported. PRRSV vaccines have been developed, including inactive virus, modified live virus, attenuated live vaccine, DNA vaccine, and immune adjuvant vaccines. However, there are certain problems with the durability and effectiveness of the licensed vaccines. Moreover, the high variability and fast-evolving populations of this RNA virus challenge the design of PRRSV vaccines, and thus effective vaccines against PRRSV have not been developed successfully. As is well known, viruses interact with the host to escape the host’s immune response and then replicate and propagate in the host, which is the key to virus survival. Here, we review the complex network and the mechanism of PRRSV–host interactions in the processes of virus infection. It is critical to develop novel antiviral strategies against PRRSV by studying these host–virus interactions and structures to better understand the molecular mechanisms of PRRSV immune escape.

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Serological Investigation of Peste Des Petits Ruminants in East Shewa and Arsi Zones, Oromia Region, Ethiopia

Veterinary Medicine International ◽

10.1155/2017/9769071 ◽

2017 ◽

Vol 2017 ◽

pp. 1-5 ◽

Cited By ~ 5

Author(s):

Getachew Gari ◽

Biressaw Serda ◽

Dejene Negesa ◽

Fethu Lemma ◽

Hagos Asgedom

Keyword(s):

Significant Variation ◽

Small Ruminants ◽

Control Measures ◽

Economic Losses ◽

Enzyme Linked Immunosorbent Assay ◽

High Seroprevalence ◽

Serum Samples ◽

Male And Female ◽

Significant Difference ◽

Important Disease

Peste des petits ruminant (PPR) is an economically important disease of small ruminants with a rapidly expanding geographical distribution. There are fragmented reports to the occurrence and distribution of the disease in Ethiopia. A total of 700 serum samples were collected from goats and sheep to detect the presence of antibody against PPR virus using Competitive Enzyme-Linked Immunosorbent Assay (C-ELISA). An overall PPR seropositivity was reported to be 48.43% in the area. There is no statistically significant difference in the seroprevalence of the disease between sheep and goats (50.85% and 46.68%), respectively. However, there was statistically significant variation (P<0.05) in the seroprevalence of the disease in young (33.9%) and adult (55.8%) age categories. The seroprevalence in male and female was 42.07% and 50.09%, respectively, where the variation was statistically not significant (P>0.05). High seroprevalence of Peste des petites ruminants in the study area indicated the virus circulation and endemicity of the disease. The disease causes substantial economic losses by affecting the livelihood of the farmers. Therefore, control measures should be put in place to minimize the loss associated with the disease.

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Identification of E2 with improved secretion and immunogenicity against CSFV in piglets

10.21203/rs.2.18234/v2 ◽

2020 ◽

Author(s):

Huiling Xu ◽

Yanli Wang ◽

Guangwei Han ◽

Weihuan Fang ◽

fang he

Keyword(s):

Single Dose ◽

Signal Peptide ◽

Classical Swine Fever Virus ◽

Subunit Vaccine ◽

Classical Swine Fever ◽

Cost Effective ◽

Fever Virus ◽

Economic Losses ◽

Swine Industry ◽

Virus Challenge

Abstract Background: Outbreaks of Classical swine fever virus (CSFV) cause significant economic losses in the swine industry. Vaccination is the major method to prevent and control the disease. As live attenuated vaccines fail to elicit differentiable immunity between infected and vaccinated animals, subunit vaccine was considered as an alternative candidate to prevent and eradicate CSFV. Subunit vaccines present advantages in DIVA immunogenicity and safety. The technology was limited due to the low yield and the high cost with multiple and large doses. The native E2 signal peptide has not been well defined before. Here, the aim of this study is to develop a cost-effective and efficacious E2 vaccine candidate against CSFV with signal peptide and E2 sequence selection. Results: A novel CSFV E2 sequence (E2ZJ) was identified from an epidemic strain of Zhejiang for outstanding secretion in baculovirus and enhanced immunogenicity. E2 secretion induced with the selected signal peptide, SPZJ (SP23), increase at least 50% as compared to any other signal peptides tested. Besides, unique antigenic features were identified in E2ZJ. E2ZJ elicited CSFV antibodies at the earlier stage than other E2 types tested in mice. Moreover, higher level of neutralization antibodies against both genotypes 1 and 2 CSFV with E2ZJ was detected than other E2s with the same dosage. Further, in piglets, E2ZJ successfully elicited neutralizing immunity. A single dose of 5 μg of E2ZJ was sufficient to induce protective antibodies against CSFV in piglets and provided 100% protection against lethal virus challenge. Conclusions: Our studies provide evidence that E2ZJ guided by a novel E2 signal peptide (SPZJ) was efficiently secreted and presented significantly improved immunogenicity than conventional E2 vaccines. Moreover, a single dose of 5 μg E2ZJ is efficacious against CSFV in piglets. Keywords: Classical swine fever virus; novel signal peptide; SPZJ-E2ZJ; subunit vaccine; protective immunity

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