scholarly journals Inactivation of Classical Swine Fever Virus in Porcine Serum Samples Intended for Antibody Detection

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 286 ◽  
Author(s):  
Denise Meyer ◽  
Anja Petrov ◽  
Paul Becher
Keyword(s):  
Neutralization Test ◽  
Classical Swine Fever ◽  
Antibody Detection ◽  
Economic Losses ◽  
Pragmatic Approach ◽  
Valuable Contribution ◽  
Serum Samples ◽  
Diagnostic Assays ◽  
Porcine Serum ◽  
Phosphate Buffered Saline

Shipping of serum samples that were taken from pigs infected with classical swine fever (CSF) virus is frequently requested with the objective of serological analyses, not only for diagnostic purposes but also for exchange of reference materials that are used as control material of diagnostic assays. On the basis of the fact that an outbreak with CSF is associated with enormous economic losses, biological safety during the exchange of reference material is of great importance. The present study aimed to establish a pragmatic approach for reliable CSF virus (CSFV) inactivation in serum without impairing antibody detection. Considering the fact that complement inactivation through heating is routinely applied, the basic idea was to combine heat treatment with the dilution of serum in a detergent containing buffer in order to facilitate the inactivation process. The results show that treatment of serum samples with phosphate buffered saline-Tween20 (final concentration = 0.15%) along with incubation at 56 °C for 30 min inactivated CSFV and such treatment with ≤ 0.25% PBS-Tween20 does not impair subsequent antibody detection by ELISA or virus neutralization test. This minimizes the risk of virus contamination and represents a valuable contribution to a safer CSF diagnosis on a national and international level.

Epidemiological survey of classical swine fever in Tibetan pigs in Nyingchi, Tibet China

2016 ◽  
Author(s):  
Jia-Kui Li ◽  
Hui Zhang ◽  
Peng Shang ◽  
Yangzom Chamba
Keyword(s):  
Classical Swine Fever ◽  
Epidemiological Survey ◽  
Economic Losses ◽  
Serum Samples ◽  
Immune Effect ◽  
Tibetan Pigs ◽  
Significant Difference ◽  
Long Time ◽  
The Government

Classical swine fever (CSF) is a major hazardous disease to the pigs and as a dangerous epidemic; it causes a serious economic losses to the pig industry. Though, a national compulsory immunization of CSF vaccines had been carried out for a long time, scarce information can be got about the immune effect of CSF in Tibetan pigs. The present study was to investigate the seroprevalence of CSF in Tibetan pigs in Nyingchi area of Tibet, China. A total 454 samples were collected from November 2014 to January 2015 and were investigated through enzyme-linked immuno sorbent assay (ELISA). The results showed that 241 (53.1%, 95% CI 48.4-57.8) pigs were found to be positive for CSF with the further distribution of 53.3% (95% CI 46.8–59.6), 49.5% (95% CI 42.2-56.8) and 93.8% (95% CI 69.8-99.8) in Tibetan counties of Nyingchi, Mainling and Gongbo'gyamda, respectively. There was no significant difference in male (52.8%, 95% CI 46.4-59.1) and female pigs (50.0%, 95% CI 42.6-57.4). Though, 53.1% of the serum samples were tested out positive to CSF, only the seroprevalence of CSF in Tibetan pigs in Gongbo'gyamda were higher than 70% which was ruled by the government. The low seroprevalence of CSF in Tibetan pigs should arise a serious concern and effective methods should be taken, in order to prevent CSF infection effectively.

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

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.

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

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 427 ◽  
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.

Development and application of an indirect enzyme-linked immunosorbent assay using recombinant S1 for serological testing of porcine epidemic diarrhea virus

2019 ◽  
Vol 65 (5) ◽  
pp. 343-352
Author(s):  
Ying Shan ◽  
Yajie Liu ◽  
Ziqi Liu ◽  
Guowei Li ◽  
Cong Chen ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Porcine Epidemic Diarrhea Virus ◽  
Fluorescent Antibody ◽  
Area Under The Curve ◽  
Antibody Detection ◽  
Economic Losses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Diarrhea Virus ◽  
Porcine Epidemic Diarrhea

Porcine epidemic diarrhea virus (PEDV) causes severe infectious diseases in all ages of swine and leads to serious economic losses. Serologic tests are widely accepted and used to detect anti-PEDV antibodies that could indicate PEDV infection or vaccination. In this study, PEDV recombinant S1 protein (rS1) was expressed with the Bac-to-Bac system and purified by nickel-affinity chromatography. An indirect enzyme-linked immunosorbent assay based on rS1 (rS1-ELISA) was then developed and optimized by checkerboard assays with serial dilutions of antigen and serum. Serum samples from 453 domestic pigs and 42 vaccinated pigs were analyzed by the indirect fluorescent antibody (IFA) test and rS1-ELISA. Taking IFA as a gold standard, rS1-ELISA produced a high sensitivity (90.7%) and specificity (94.6%) by a receiver operating characteristic (ROC) curve. In addition, ROC analysis also revealed that rS1-ELISA was consistent with IFA (area under the curve 0.9583 ± 0.0082). This rS1-ELISA was then applied to antibody detection in inactivated PEDV vaccinated pigs. The antibody could be detected 2–4 weeks after the first inoculation. These results indicated that the rS1-ELISA established in this study provides a promising and reliable tool for serologic detection of anti-PEDV IgG antibodies in infected or vaccinated pigs.

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

2020 ◽  
Author(s):  
Haoyang Yu ◽  
Luhua Zhang ◽  
Yunfeng Cai ◽  
Tao Peng ◽  
Lei Liu ◽  
...  
Keyword(s):  
Average Rate ◽  
Classical Swine Fever ◽  
Control Measures ◽  
Hunan Province ◽  
Economic Losses ◽  
Respiratory Syndrome Virus ◽  
Growth Stages ◽  
Serum Samples ◽  
Swine Industry ◽  
Effective Prevention

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.

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

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

scholarly journals Construction of eGFP-Tagged Senecavirus A for Facilitating Virus Neutralization Test and Antiviral Assay

Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 283 ◽  
Author(s):  
Fuxiao Liu ◽  
Yilan Huang ◽  
Qianqian Wang ◽  
Hu Shan
Keyword(s):  
Reverse Genetics ◽  
Fluorescent Protein ◽  
Neutralization Test ◽  
High Capacity ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Serum Samples ◽  
Neutralization Titer ◽  
Porcine Serum

Senecavirus A (SVA), also known as Seneca Valley virus, is an emerging virus that causes vesicular disease in pigs. This virus belongs to the genus Senecavirus in the family Picornaviridae. The SVA CH-LX-01-2016 was isolated from Guangdong Province of China in 2016. In this study, a recombinant SVA CH-LX-01-2016 was constructed using reverse genetics, and proven to be able to express efficiently an enhanced green fluorescent protein (eGFP) in vitro. This eGFP-tagged recombinant SVA (rSVA-eGFP) exhibited a high capacity for viral replication. Its fluorescence-tracked characteristics greatly facilitated both virus neutralization test (VNT) and antiviral assay. The rSVA-eGFP-based VNT was used to detect eight porcine serum samples, out of which four were determined to be neutralization titer-positive. Subsequently, two antiviral drugs, ribavirin and apigenin, were assayed for evaluating both effects against the rSVA-eGFP in vitro. The result showed that only the ribavirin exhibited an anti-SVA activity.

scholarly journals Delayed neutralizing antibody response in the acute phase correlates with severe progression of COVID-19

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hitoshi Kawasuji ◽  
Yoshitomo Morinaga ◽  
Hideki Tani ◽  
Miyuki Kimura ◽  
Hiroshi Yamada ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Pseudotyped Virus ◽  
Serum Samples ◽  
Neutralization Activity ◽  
Neutralizing Activity ◽  
Time Points ◽  
Moderate Disease ◽  
Activity Dynamics

AbstractAdaptive immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dynamics remain largely unknown. The neutralizing antibody (NAb) levels in patients with coronavirus disease 2019 (COVID-19) are helpful for understanding the pathology. Using SARS-CoV-2 pseudotyped virus, serum sample neutralization values in symptomatic COVID-19 patients were measured using the chemiluminescence reduction neutralization test (CRNT). At least two sequential serum samples collected during hospitalization were analyzed to assess NAbs neutralizing activity dynamics at different time points. Of the 11 patients, four (36.4%), six (54.5%), and one (9.1%) had moderate, severe, and critical disease, respectively. Fifty percent neutralization (N50%-CRNT) was observed upon admission in 90.9% (10/11); all patients acquired neutralizing activity 2–12 days after onset. In patients with moderate disease, neutralization was observed at earliest within two days after symptom onset. In patients with severe-to-critical disease, neutralization activity increased, plateauing 9–16 days after onset. Neutralization activity on admission was significantly higher in patients with moderate disease than in patients with severe-to-critical disease (relative % of infectivity, 6.4% vs. 41.1%; P = .011). Neutralization activity on admission inversely correlated with disease severity. The rapid NAb response may play a crucial role in preventing the progression of COVID-19.

scholarly journals Sero-epidemiological survey of bluetongue disease in one-humped camel (Camelus dromedarius) in Kassala State, Eastern Sudan

2021 ◽  
Vol 74 (1) ◽  
Author(s):  
Molhima M. Elmahi ◽  
Mohammed O. Hussien ◽  
Abdel Rahim E. Karrar ◽  
Amira M. Elhassan ◽  
Abdel Rahim M. El Hussein
Keyword(s):  
Risk Factors ◽  
Potential Risk ◽  
Animal Health ◽  
Water Source ◽  
Economic Losses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Cross Sectional ◽  
Potential Risk Factors ◽  
Eastern Sudan

Abstract Background Bluetongue (BT) is a vector-borne viral disease of ruminant and camelid species which is transmitted by Culicoides spp. The causative agent of BT is bluetongue virus (BTV) that belongs to genus Orbivirus of the family Reoviridae. The clinical disease is seen mainly in sheep but mostly sub-clinical infections of BT are seen in cattle, goats and camelids. The clinical reaction of camels to infection is usually not apparent. The disease is notifiable to the World Organization for Animal Health (OIE), causing great economic losses due to decreased trade and high mortality and morbidity rates associated with bluetongue outbreaks. The objective of this study was to investigate the seroprevalence of BTV in camels in Kassala State, Eastern Sudan and to identify the potential risk factors associated with the infection. A cross sectional study using a structured questionnaire survey was conducted during 2015–2016. A total of 210 serum samples were collected randomly from camels from 8 localities of Kassala State. The serum samples were screened for the presence of BTV specific immunoglobulin (IgG) antibodies using a competitive enzyme-linked immunosorbent assay (cELISA). Results Seropositivity to BTV IgG was detected in 165 of 210 camels’ sera accounting for a prevalence of 78.6%. Potential risk factors to BTV infection were associated with sex (OR = 0.061, p-value = 0.001) and seasonal river as water source for drinking (OR = 32.257, p-value = 0.0108). Conclusions Sex and seasonal river as water source for drinking were considered as potential risk factors for seropositivity to BTV in camels. The high prevalence of BTV in camels in Kassala State, Eastern Sudan, necessitates further epidemiological studies of BTV infection in camels and other ruminant species to better be able to control BT disease in this region.

Molecular detection of equine infectious anemia virus in clinically normal, seronegative horses in an endemic area of Mexico

2021 ◽  
pp. 104063872110061
Author(s):  
César I. Romo-Sáenz ◽  
Patricia Tamez-Guerra ◽  
Aymee Olivas-Holguin ◽  
Yareellys Ramos-Zayas ◽  
Nelson Obregón-Macías ◽  
...  
Keyword(s):  
Nested Pcr ◽  
Equine Infectious Anemia Virus ◽  
Antibody Detection ◽  
Economic Losses ◽  
Clinically Normal ◽  
Pcr Product ◽  
Surveillance Programs ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Equine Industry

Equine infectious anemia (EIA) is a highly infectious disease in members of the Equidae family, caused by equine infectious anemia virus (EIAV). The disease severity ranges from subclinical to acute or chronic, and causes significant economic losses in the equine industry worldwide. Serologic tests for detection of EIAV infection have some concerns given the prolonged seroconversion time. Therefore, molecular methods are needed to improve surveillance programs for this disease. We attempted detection of EIAV in 6 clinical and 42 non-clinical horses in Nuevo Leon State, Mexico, using the agar gel immunodiffusion (AGID) test for antibody detection, and nested and hemi-nested PCR for detection of proviral DNA. We found that 6 of 6, 5 of 6, and 6 of 6 clinical horses were positive by AGID, nested PCR, and hemi-nested PCR, respectively, whereas 0 of 42, 1 of 42, and 9 of 42 non-clinical horses were positive by these tests, respectively. BLAST analysis of the 203-bp 5′-LTR/ tat segment of PCR product revealed 83–93% identity with EIAV isolates in GenBank and reference strains from other countries. By phylogenetic analysis, our Mexican samples were grouped in a different clade than other sequences reported worldwide, indicating that the LRT/ tat region represents an important target for the detection of non-clinical horses.

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