Transmissible Gastroenteritis In Pigs Research Articles

Coronaviruses: modern taxonomy and research chronology

The classification of coronaviruses began in 1968 when five viruses (IBV, MHV, B814, 229E, and OC43) were united into an independent group, “coronaviruses”, based on the characteristic morphology of the virions. In 1971, the genus Coronavirus was formed, and in 1975, the family Coronaviridae, which in 1996 was included in the order Nidovirales. In 2009, the Coronaviridae family was divided into subfamilies. In 2018, new taxa of viruses were created – region, suborder, and subgenus, and in 2019 – kingdom, type, and class. According to the International Committee on Taxonomy of Viruses, issue No. 37 of 07.2021 (ratification of 03.2022), the family Coronaviridae belongs to the region Riboviria, kingdom Orthornavirae, phylum Pisuviricota, class Pisoniviricetes, order Nidovirales, suborder Cornidovirineae. The Coronaviridae family includes 54 viruses, which are grouped into three subfamilies (Letovirinae, Orthocoronavirinae, Pitovirinae), six genera (Alphaletovirus, Alphacoronavirus, Betacoronavirus, Deltacoronavirus, Gammacoronavirus, Alphapironavirus) and 28 subgenera. Representatives of the most numerous subfamily Orthocoronavirinae infect various species of mammals and birds, causing various pathologies: respiratory and intestinal infections, polyserositis, myocarditis, hepatitis, nephritis, neuroinfections, immunopathology. In particular, viruses that cause infectious bronchitis in chickens, transmissible gastroenteritis in pigs, epidemic diarrhea in pigs, encephalomyelitis in pigs, coronavirus infection in cattle, and epizootic catarrhal gastroenteritis in minks are relevant for veterinary practice. The natural reservoirs of coronaviruses from the genera Alphacoronavirus and Betacoronavirus are bats and birds from the genera Gammacoronavirus and Deltacoronavirus. Particularly dangerous human coronaviruses are SARS-CoV, MERS-CoV and SARS-CoV-2, which cause emergent infections. The circulation of SARS-CoV, MERS-CoV, and SARS-CoV-2 among animals is shown. The natural reservoir of these viruses is bats, and the intermediate hosts for SARS-CoV are Himalayan civets, one-humped camels for MERS-CoV, and pangolins for SARS-CoV-2. The circulation of SARS-CoV-2 among different species of domestic and wild animals leads to the accumulation of mutations, which causes the adaptation of the virus to new hosts and ecological niches and its subsequent introduction into the human population.

The N-Terminal Domain of Spike Protein Is Not the Enteric Tropism Determinant for Transmissible Gastroenteritis Virus in Piglets.

Transmissible gastroenteritis virus (TGEV) is the etiologic agent of transmissible gastroenteritis in pigs, and the N-terminal domain of TGEV spike protein is generally recognized as both the virulence determinant and enteric tropism determinant. Here, we assembled a full-length infectious cDNA clone of TGEV in a bacterial artificial chromosome. Using a novel approach, the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) systems efficiently and rapidly rescued another recombinant virus with a 224-amino-acid deletion in the N-terminal domain of the TGEV Spike gene (S_NTD224), which is analogous to the N-terminal domain of porcine respiratory coronavirus. S_NTD224 notably affected the TGEV growth kinetics in PK-15 cells but was not essential for recombinant virus survival. In animal experiments with 13 two-day-old piglets, the TGEV recombinant viruses with/without S_NTD224 deletion induced obvious clinical signs and mortality. Together, our results directly demonstrated that S_NTD224 of TGEV mildly influenced TGEV virulence but was not the enteric tropism determinant and provide new insights for the development of a new attenuated vaccine against TGEV. Importantly, the optimized reverse genetics platform used in this study will simplify the construction of mutant infectious clones and help accelerate progress in coronavirus research.

Патоморфологічні зміни за трансмісивного гастроентериту поросят

Transmisive gastroenteritis of pigs is currently registered in all countries of the world with intensive management of pig production, there are practically no large pig farms in which there is no transmissible gastroenteritis of pigs. Also the disease is widespread in pig farms of Ukraine. Transmissible gastroenteritis sick piglets in the first week after birth. During the initial appearance of the disease in a short time can be spread among pigs of all age groups with almost 100% death in 1 – to 10-day piglets and 4% among weaned piglets. In the literature adequately describes the etiology, pathogenesis, clinical picture and treatment of the disease, but pathological changes described not fully. The purpose of our research was to study the pathological morphology changes in transmissible gastroenteritis of pigs. To achieve this goal were the following objectives: to conduct a postmortem of sick pigs to transmissible gastroenteritis, to study macroscopic and microscopic changes in internal organs of pigs in this disease and to describe changes in the internal organs that were not previously documented. Work completed during 2016–2017 years on the basis of one of the private pig farms of industrial type Kyiv region and of the Department of pathological anatomy, National University of life and environmental Sciences of Ukraine, which was delivered to autopsy the dead animals. Postmortem 12 corpses of piglets that died from transmissible gastroenteritis conducted in the dorsal position by the method of partial evisceration, microscopic studies were performed according to standard techniques. When conducting pathological studies of pigs died from transmissible gastroenteritis we had installed the following changes: the mucous membrane of the stomach in a state of catarrhal inflammation, with hemorrhages and erosions; the mucous membrane of the small intestine has the symptoms of a catarrhal-hemorrhagic inflammation. Blind the colon and the intestines are found the superficial necrosis in the form of a scaly plaque. Microscopic studies found atrophy of the villi of the jejunum and the iliac colon. The pyknosis and lysis of nuclei, necrosis of individual epithelial cells. The destruction of the villi up to a section of the crypts. Smooth muscle cells of the muscle membrane was in a state of granular dystrophy.

ВЫДЕЛЕНИЕ И ИДЕНТИФИКАЦИЯ ВИРУСА ЭПИЗООТИЧЕСКОЙ ДИАРЕИ СВИНЕЙ ПРИ ВСПЫШКЕ В КРУПНОМ СВИНОВОДЧЕСКОМ ХОЗЯЙСТВЕ

Epizootic diarrhea fever (EDF), characterized by acute enteritis and hard intestinal disorders, is caused by the virus of the same group of С oronavirus ( Coronaviridae ) as the virus of transmissible gastroenteritis of pigs, coronavirus of cats and dogs, and human 229E strain. From 2005, at the territory of the Russian Federation the outbreaks of the disease were recorded, clinically similar to pig transmissible gastroenteritis. The infections caused a loss of piglets, in some cases up to 80 %. However, the sows in such farms have been vaccinated against the transmissible gastroenteritis of pigs. The aim of our study was to isolate in cell culture and identify an infectious agent that causes the outbreaks with diarrheal syndrome in pigs. From the pathological material of 3-5-day-old piglets with the pathology a RNA virus was isolated and identified as the virus of epizootic diseases of pigs. Virus infectivity in the fifth passage in Vero cell culture was 10 3,50 ТCID 50/sm 3. The isolate was named as BS-08. To date, there are 25 successive passages of the virus in cell culture. A citopatic effect is registered in 24-48 hours, and the infectious titer (titer of citopatic effect — TCE) makes 10 4,75-10 5,50 TCID 50/sm 3.

Desarrollo de una prueba de reacción en cadena de la polimerasa anidada para el diagnóstico de la gastroenteritis transmisible del cerdo

The aim of this study was to develop a nested polymerase chain reaction (nested PCR) for the rapid detection of transmissible gastroenteritis virus (TGEV) of pigs. The primers were designed on the basis of highly conserved regions of several TGEV sequences included in the analysis. External primers were used to amplify a fragment of the expected size (441 bp) in all the samples evaluated using reverse transcriptase polymerase chain reaction (RT-PCR), but with very low intensity. In the second amplification (nested PCR), internal primers were used to amplify a fragment of the expected size (168 bp), with good concentration. The performance of the test based on virus isolates in tissue culture and in clinical samples was judged good for the virological diagnosis of transmissible gastroenteritis of pigs.

Rapid detection of porcine circovirus type 2 using a TaqMan-based real-time PCR

Porcine circovirus type 2 (PCV2) and the associated disease postweaning multisystemic wasting syndrome (PMWS) have caused heavy losses in global agriculture in recent decades. Rapid detection of PCV2 is very important for the effective prophylaxis and treatment of PMWS. To establish a sensitive, specific assay for the detection and quantitation of PCV2, we designed and synthesized specific primers and a probe in the open reading frame 2. The assay had a wide dynamic range with excellent linearity and reliable reproducibility, and detected between 102 and 1010 copies of the genomic DNA per reaction. The coefficient of variation for Ct values varied from 0.59% to 1.05% in the same assay and from 1.9% to 4.2% in 10 different assays. The assay did not cross-react with porcine circovirus type 1, porcine reproductive and respiratory, porcine epidemic diarrhea, transmissible gastroenteritis of pigs and rotavirus. The limits of detection and quantitation were 10 and 100 copies, respectively. Using the established real-time PCR system, 39 of the 40 samples we tested were detected as positive.

Potential animal health hazards of pork and pork products.

The animal health hazards associated with the importation of pork and pork products include four viral agents: foot and mouth disease, classical swine fever (hog cholera), African swine fever, and swine vesicular disease viruses. The safety of importing pork from a zone infected with one or more of these diseases can be adequately determined only through risk assessment. This also applies for the safety of importing pork products which have undergone some form of processing (fully cooked pork products are not counted here). For each disease, the agent (pH and temperature lability), target organs, agent survival in pork and pork products, and agent quantification are discussed. Agent quantification is an input of the risk assessment which measures the viral titres in waste pork and pork products in relation to the oral infective dose estimated for each disease. Two other viral diseases, transmissible gastroenteritis of pigs and porcine reproductive and respiratory syndrome, are presented to illustrate why these two diseases are not hazards when associated with pork and pork products.

Elimination of transmissible gastroenteritis virus from a pig farm by culling and serological surveillance.

The first and only outbreak of transmissible gastroenteritis in pigs in Ireland occurred in 1984 in a 650-sow unit which was one of three such units owned by one enterprise which supplied pigs to a 12,000 head fattening unit in the same ownership. The depopulation of the clinically infected unit and extensive serological monitoring of pigs in the other units and in pig farms throughout the country has proved successful in the elimination of transmissible gastroenteritis infections from pigs in Ireland.

Transmissible gastroenteritis in pigs in south east Spain: prevalence and factors associated with infection.

In the Murcia region of south east Spain, epidemics of transmissible gastroenteritis-like disease have occurred in pigs every three years since 1980. In 1987 a sero-epidemiological survey was conducted to estimate the prevalence and spread of transmissible gastroenteritis virus (TGEV) infection among breeding pigs and farms, and to determine any association between the infection and herd size and geographical zone. The Murcia region was divided into four geographical zones and the farms were classified by size into four categories. The random sample was statistically representative of both the breeding stock and the farms in each geographical zone, and the analyses involved 6000 breeding pigs from 480 farms. The immunological techniques employed were the indirect ELISA and the blocking ELISA. The prevalence of seropositive breeding pigs was 1.27 +/- 0.28 per cent and the prevalence of infected farms was 5 +/- 1.94 per cent. On the infected farms, the prevalence of seropositive pigs ranged from 5 to 60 per cent. The infection occurred throughout the Murcia region, but a significant association (P < 0.01) was observed between the geographical zone and the prevalence of TGEV infection. Herds with > or = 50 breeding pigs had a greater prevalence (P < 0.01) of TGEV infection.

Solid phase immune electron microscopy for diagnosis of transmissible gastroenteritis in pigs

A serological trapping technique is described for detecting transmissible gastroenteritis (tge) virus in faeces. The technique involves the coating of electron microscope grids with protein A and specific tge virus antiserum. Optimal conditions for performing this solid phase immune electron microscopy technique were a concentration 250 µg ml−1 of protein A; 1:100 diluted rabbit anti-tge virus hyperimmune serum for coating the grids and overnight incubation with virus samples. The possibility of detecting coronavirus in crude faeces was highly improved with solid phase immune electron microscopy, compared with conventional negative staining electron microscopy, by specific trapping of virus and prevention of adsorption of contaminants. The sensitivity of the method was evaluated by coded investigation of a dilution series of stock virus mixed with different pools of faeces. The improvement of virus detection in faeces by solid phase immune electron microscopy, compared with standard electron microscopy was at least 100-fold. Faecal shedding of coronavirus by pigs infected with virulent and attenuated strains of tge virus was studied. Virus detection in faeces by a standard electron microscopy technique was not practical, since the virus was obscured by a large quantity of debris in the faeces. By using solid phase immune electron microscopy, however, the aspect of the specimens on the grids improved so much that, in addition to more common immunofluorescence, the technique might be useful as a diagnostic test for tge. Virus was detected in daily faecal samples from one or two days after experimental infection with virulent tge virus, until death in five out of eight animals. Unlike immunofluorescence, solid phase immune electron microscopy may be used for diagnosis in living animals.

Non specific defenses against transmissible gastroenteritis in pigs. Study of virus-lymphocyte interactions

Non specific defenses against transmissible gastroenteritis in pigs. Study of virus-lymphocyte interactions

Transmissible gastroenteritis in pigs : use of an inactivated oil emulsion vaccine for boosting the immunity in previously infected sows

Transmissible gastroenteritis in pigs : use of an inactivated oil emulsion vaccine for boosting the immunity in previously infected sows

Transmissible gastroenteritis in pigs : selection in tissue culture (RP.TG cells) of TGE virus strains resistant at pH 2.0 to digestive enzymes and attenuated for the new-born piglet

Transmissible gastroenteritis in pigs : selection in tissue culture (RP.TG cells) of TGE virus strains resistant at pH 2.0 to digestive enzymes and attenuated for the new-born piglet

Transmissible gastroenteritis in pigs: some observations on laboratory aids to diagnosis.

Thirty seven piglets with transmissible gastroenteritis (TGE) and 41 with other enteric diseases were examined for evidence of villous atrophy and reduced lactase activity. Widespread villous atrophy appeared indicative of TGE whereas normal lactase activity tended to exclude this possibility. However, both tests are far from specific and neither is recommended to practitioners as an aid to clinical diagnosis.

Transmissible gastroenteritis in pigs: an epidemiological study of outbreaks in East Anglia.

Transmissible gastroenteritis in pigs: an epidemiological study of outbreaks in East Anglia.

A Survey of the Viruses of Farm Animals in Northern Ireland

SUMMARY Continuing surveillance of the viral infections of farm animals in Northern Ireland since 1962, using virus isolation procedures, serological tests, direct electron microscopic examination of clinical material and clinical and histopathological investigations show that a wide range of viruses are present in Northern Ireland. The agents detected are recorded. There is evidence for the absence of several agents, viz foot and mouth disease virus; swine fever virus; and transmissible gastroenteritis of pigs. Newcastle disease virus was recovered but the disease is not now present in Northern Ireland, at least in a clinically recognizable form.

On the mechanism of immunity of transmissible gastroenteritis in pigs

On the mechanism of immunity of transmissible gastroenteritis in pigs