Toxoplasmosis In Pigs Research Articles

Literature Study Of The Incidence Of Toxoplasmosis In Pigs

Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii. Cats are the main or definitive host of T. gondii. This study was conducted with the aim of looking at the level of Toxoplasmosis incidence in pigs in several regions in Indonesia and to see the relationship between risk factors and the incidence of Toxoplasmosis in pigs. The prevalence of Toxoplasmosis in pigs in several regions in Indonesia varies. The highest prevalence is in the Baliem Valley with a prevalence of 75.9%, while the lowest prevalence of pigs infected with T. gondii was in Manado, which was 0%. Risk factors that affect the incidence of toxoplasmosis in pigs are the presence of cats as the definitive host, maintenance, temperature and humidity, meanwhile, age has no effect on the incidence of toxoplasmosis in pigs.

Outbreak of toxoplasmosis associated with muscular lesions in finishing pigs caused by an atypical Toxoplasma gondii genotype.

Toxoplasma gondii infections are usually asymptomatic in pigs, and an acute clinical disease is rare in this host. This study aimed to determine the pathological and molecular aspects of an outbreak of fatal systemic toxoplasmosis in finishing pigs in Brazil. The outbreak occurred on a commercial finishing pig farm in the state of Santa Catarina in southern Brazil. The farm had 1500 pigs and 3.8% of mortality rate during the outbreak. The pigs had fever, anorexia, apathy, and locomotor deficits. Seven pigs were necropsied. Gross findings included multifocal to coalescent pale areas in skeletal muscles, lymphadenomegaly, hepatosplenomegaly, and non-colapsed lungs. The histological findings included granulomatous lymphadenitis, hepatitis and splenitis, necrotizing myositis, and lymphoplasmacytic interstitial pneumonia. Lung and liver lesions were occasionally accompanied by T. gondii parasitic structures. Positive immunolabeling for T. gondii tachyzoites and encysted bradyzoites was detected in all examined pigs. PCR-RFLP (11 markers) and microsatellite analysis (15 markers) identified the non-archetypal genotype #278 in pigs. This is the first report of systemic toxoplasmosis in pigs with muscle lesions and additionally shows the diversity of disease-causing T. gondii genotypes circulating in animals in Brazil.

Molecular detection and genetic characterization of Toxoplasma gondii in pork from Chongqing, southwest China

Raw or undercooked meat is an important source of Toxoplasma gondii infection in China, but there is little research data on these infections in Chongqing. This study determined the prevalence of T. gondii, and its genotypes, in pork. A total of 1,223 diaphragm muscle samples were collected from eight slaughterhouses and 79 markets and detected by PCR amplification of the ITS gene. All of the positive samples were used for genotype identification by PCR-RFLP with 11 genetic markers. The total positive rate of T. gondii in Chongqing pork was 8.7%, and differences in T. gondii infection rates were found between different districts (0%–23.3%), seasons (e.g., 4.3% from Spring, 7.3% from Summer, 11.4% from Autumn, 12.0% from Winter) and years (2.7%–14.3%). Six samples were successfully genotyped, of which one was identified as ToxoDB#9 and five were ToxoDB#9-like. This was the first continuous study about the prevalence of T. gondii in pork in Chongqing for several years. Slaughterhouses in different districts, pork source, farm scale, season and year were potential risk factors for T. gondii contamination by the univariate logistic regression, and using multivariate logistic regression districts, pork source and year were the independent risk factor. These data may help reducing the levels of toxoplasmosis in pigs and humans in Chongqing.

High level of infection by Toxoplasma gondii in pigs slaughtered in the city of São Luís, Maranhão.

A serological, molecular and histopathological study was carried out in order to investigate occurrences of Toxoplasma gondii in pigs slaughtered with and without inspection service. Serum samples were collected from 60 pigs to detect anti-T. gondii antibody by indirect fluorescent antibody (IFAT). Tongue, masseter and diaphragm fragments were also collected for parasite DNA detection by means of the polymerase chain reaction (PCR) and histopathological analysis. The serological results showed that 77% (44/60) of the pigs were positive. Regarding PCR, 66.67% (40/60) were positive for T. gondii. Among the tissues evaluated, the diaphragm was the one with the highest frequency of positivity (40%; 24/60), followed by the masseter (38.33%; 23/60) and tongue (33.3%; 20/60). Histopathological changes were only observed in the diaphragm, which presented inflammatory infiltrates of lymphohistiocytic and neutrophilic types. These results not only show the potential threat of T. gondii to human health, but also demonstrate the dynamic epidemiological situation of toxoplasmosis in pigs in the city of São Luís, providing support for food security regarding pigs and for T. gondii control programs in Brazil.

Gold standards are out and Bayes is in: Implementing the cure for imperfect reference tests in diagnostic accuracy studies

Bayesian mixture models, often termed latent class models, allow users to estimate the diagnostic accuracy of tests and true prevalence in one or more populations when the positive and/or negative reference standards are imperfect. Moreover, they allow the data analyst to show the superiority of a novel test over an old test, even if this old test is the (imperfect) reference standard. We use published data on Toxoplasmosis in pigs to explore the effects of numbers of tests, numbers of populations, and dependence structure among tests to ensure model (local) identifiability. We discuss and make recommendations about use of priors, sensitivity analysis, model identifiability and study design options, and strongly argue for the use of Bayesian mixture models as a logical and coherent approach for estimating the diagnostic accuracy of two or more tests.

Molecular detection and genetic characterization of Toxoplasma gondii in pork in Shanghai, China

Toxoplasma gondii in pork products has become an important public health problem worldwide. However, the prevalence of pork with T. gondii has rarely been reported. In this study, we assessed the prevalence and genotypic characterization of T. gondii in pig meats. Five slaughterhouses and 100 retail stores were surveyed in Shanghai. A total of 750 samples were collected and 63 (8.4%) samples were found to be positive by nested PCR targeting the ITS1 gene. Three of the slaughterhouses and 20 retail stores had positive specimens, and a higher infection rate was seen in the hot season than in the cold season. Similar positive rates were detected in pork from slaughterhouses (8.2%) and from retail stores (8.7%). The prevalence in supermarkets (13.3%) was higher than in farmers markets (4.0%). All positive samples were typed at 11 loci using PCR-RFLP methods. Two samples were completely typed at all loci, and two samples were typed at eight loci, all were identified as ToxoDB#9. To our knowledge, there is no previously published report of T. gondii in pork in Shanghai, and these results will provide data to support food safety and will benefit the control of toxoplasmosis in pigs.

Comparison of commercial ELISA tests for the detection of Toxoplasma antibodies in the meat juice of naturally infected pigs

Toxoplasmosis is a globally distributed protozoal zoonosis. Pigs are considered an important reservoir of Toxoplasma gondii and pork a major infection source of human toxoplasmosis. ELISA methods are commonly used diagnostic tools for detecting Toxoplasma infections. They are also used for slaughterhouse-based serological monitoring of toxoplasmosis in pigs to identify positive farms. The methods used are non-standardised with varying sensitivity and specificity. In our study, four commercial ELISA tests for the detection of Toxoplasma antibodies in the meat juice of slaughter pigs were compared with a modified agglutination test (MAT) as a reference. The cut-off values of the ELISA tests provided by the manufacturer varied between 0.20 and 0.50, and clearly influenced prevalence. The sensitivity of tests I, II and III varied between 96.4 and 78.6. Sensitivity was unacceptably low (3.6) for test IV (cut-off=0.30). Tests I, II and III had the highest accuracy and the best agreement with the reference test when a cut-off of 0.30 was used. Test II and III showed very good agreement (K=0.92 and 0.84, respectively) with the MAT. A very strong correlation (Pearson correlation >0.89) was observed between the S/P values of tests I, II and III. Our results demonstrate that the test and cut-off value used influence the results of the apparent seroprevalence studies.

Experimental Toxoplasma gondii infections in pigs: Humoral immune response, estimation of specific IgG avidity and the challenges of reproducing vertical transmission in sows

Ten pregnant sows were experimentally inoculated per os with T. gondii in order to investigate vertical and galactogenic transmission of the parasite and the evolution and maturation of the specific IgG humoral response in the sows and piglets. Five seronegative sows received 104T. gondii (CZ isolate clone H3) sporulated oocysts during late-pregnancy (Exp. 1), three sows received 104 oocysts during mid-pregnancy (Exp. 2) and three sows from Exp. 1 (and two seronegative sows) were re-inoculated with 105 oocysts during a further pregnancy (late-pregnancy) (Exp. 3). Besides, six 4.5 week-old piglets inoculated per os with 5×103 oocysts were also included in the serological investigations. All animals seroconverted (PrioCHECK Toxoplasma Ab porcine ELISA, Prionics, Switzerland) by 2–3 weeks post inoculation (wpi) and remained seropositive for at least 38 weeks or until euthanasia. Four chronically infected sows from Exp. 1 and 2 were serologically monitored during a further pregnancy and no reactivation, but a decrease of the antibody levels was observed at farrowing (Exp. 4). In all experiments, the specific IgG-avidity was initially low, increased during the course of infection and after re-inoculations. An avidity index (AI) ≥40% could be used to rule out recent infections (<8 weeks) in most (15 of 16) animals. In some piglets (18.6% of 70) delivered by inoculated sows (Exp. 1 and 2), maternal antibodies were still detectable at 2 months (but not by 3 months) of age, with constant high avidity values, comparable to those of the dams at farrowing.In all experiments, the sows remained asymptomatic and delivered non-infected offspring at term. A total of 208 normal and 5 stillborn piglets delivered by the inoculated sows (Exp. 1–4) tested serologically negative before colostrum uptake. Placentas (n=88) from all sows and tissues (brain, liver, lung, heart, and masseter muscle) from 56 delivered piglets were analysed histopathologically and by real-time PCR for T. gondii with negative results. Colostrum and milk samples from all sows were negative by real-time PCR for T. gondii DNA. In addition, no seroconversion was observed in 16 piglets from seronegative dams that were transferred to infected dams one day after birth to detect a possible infection through colostrum or milk during the suckling period. Although vertical transmission of T. gondii was demonstrated in naturally infected pigs, many factors involved in the outcome of vertical transmission and congenital toxoplasmosis in pigs are still unknown.

Dextran sulfate inhibits acute Toxoplama gondii infection in pigs.

BackgroundToxoplasma gondii is a highly prevalent protozoan that can infect all warm-blooded animals, including humans. Its definitive hosts are Felidae and its intermediate hosts include various other mammals and birds, including pigs. It is found in the meat of livestock which is a major source of human infection. Hence the control of toxoplasmosis in pigs is important for public health. We previously showed that dextran sulfate (DS), especially DS10 (dextran sulfate MW 10 kDa), is effective against T. gondii infection both in vitro and in mice. In this study, we asked whether DS affects T. gondii infection of pigs, one of the main animal sources of toxoplasmosis transmission to humans.MethodsFourteen-day-old male pigs (n = 10) were infected with T. gondii and then immediately treated with different doses of DS10; clinical, pathological, and immunological analyses were performed 5 days post-infection.ResultsDS10 had an inhibitory effect on toxoplasmosis in pigs. Intravenous injection of DS10 prevented the symptoms of toxoplasmosis and reduced the parasite burden and inflammation induced by T. gondii infection. High-dose DS10 (500 μg per head) caused reversible hepatocellular degeneration of the liver; middle-dose DS10 (50 μg per head) was effective against toxoplasmosis in pigs without causing this side effect.ConclusionsOur data suggest that middle-dose DS10 led to minimal clinical symptoms of T. gondii infection and caused little hepatocellular degeneration in our pig model, thereby demonstrating its potential as a new treatment for toxoplasmosis. These data should be very beneficial to those interested in the control of toxoplasmosis in pigs.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1421-9) contains supplementary material, which is available to authorized users.

Identification of Genes Expressed DuringToxoplasma gondiiInfection by in Vivo-Induced Antigen Technology (IVIAT) with Positive Porcine Sera

Infection of pigs with Toxoplasma gondii is a common source of human toxoplasmosis and causes serious economic losses. In vivo-induced antigen technology (IVIAT) is an effective immunological technique to identify the antigens that a pathogen specifically expressed during infection. To discover the genes that are important in T. gondii infection of pigs, we employed IVIAT using sera from infected pigs. Fourteen antigens were identified including microneme protein 11 (MIC11), dense granule protein 5 (GRA5), 18 kDa cyclophilin (C-18), serine proteinase inhibitor (PI), calmodulin (CaM), leucine-rich repeat protein ( LRRP), D-3-phosphoglycerate dehydrogenase (D3PD), elongation factor 1-gamma (EF1), and 6 hypothetical proteins. The increased transcription levels of 5 (MIC11, GRA5, C-18, PI, and CaM) of the 14 molecules identified by IVIAT were confirmed by real-time PCR. The full length or partial proteins encoded by these 5 genes were expressed in Escherichia coli , and their immunogenicity was confirmed by Western blot analysis with positive porcine sera. Further functional studies were conducted with CaM. Suppression of CaM expression by RNA interference decreased T. gondii tachyzoites cell attachment, invasion, and egress but did not influence their replication. The proteins identified in this study are predicted to be involved in cell invasion, ion-protein binding, protein folding, biosynthesis, and metabolism. The results of the functional analysis support the hypothesis that CaM contributes to parasite pathogenesis during infection. These results may have significant implications for the discovery of candidate molecules for the development of potential therapies and preventive measures against toxoplasmosis in pigs.

Detection of Acute Toxoplasmosis in Pigs Using Loop-Mediated Isothermal Amplification and Quantitative PCR

A loop-mediated isothermal amplification (LAMP) assay allows rapid diagnosis of Toxoplasma gondii infection. In the present study, the LAMP assay was evaluated using blood from both naturally and experimentally infected pigs. The sensitivity of the LAMP assay was compared with that of Q-PCR. Both assays detected T. gondii in the blood of experimentally infected pigs, with 100% agreement. In infected blood samples, the parasite was detected as early as 2 days post-infection and reached a peak in 3-5 days. In 216 field serum samples, the detection rates of LAMP and Q-PCR assays were 6.9% and 7.8%, respectively. This result indicates that the sensitivity of the LAMP assay was slightly lower than that of the Q-PCR assay. However, the LAMP may be an attractive diagnostic method in conditions where sophisticated and expensive equipment is unavailable. This assay could be a powerful supplement to current diagnostic methods.

Occurrence and genetic characterization of Toxoplasma gondii in naturally infected pigs

The protozoan Toxoplasma gondii is an obligate intracellular parasite that infects a wide range of warm-blooded vertebrates. The data about the occurrence of toxoplasmosis in slaughter pigs in the Slovak Republic are still missing. The aim of our study was to estimate the prevalence of toxoplasmosis in pigs from Slovakia during the period of 2006-2010 by ELISA and PCR methods. In sera of 970 slaughter pigs, 2.16% seropositivity to T. gondii was detected. In tissue samples of seropositive pigs the presence of T. gondii DNA was confirmed. In six monitored Slovak regions the seropositivity varied between 1.11 and 3.48%. The statistically significant differences were recorded between the Košice and Prešov region. The seroprevalence of toxoplasmosis in sows (4.26%) was two times higher than that in slaughter pigs (2.06%) (OR = 2.12; 95% CI = 0.48-9.36). Presence of Toxoplasma gondii in tissues of seropositive pig isolates was confirmed by TGR1E and B1 genes and analysis of DNA polymorphism at SAG2 and ROP1 genes revealed the presence of virulent strain of genotype I in 85.7% of infected pigs and an avirulent strain (genotype II) in 14.3% of pigs.

Soil contamination of Toxoplasma gondii oocysts in pig farms in central China

Toxoplasmosis in pigs is a large threat to pig industry as well as pork consumers. Most pigs become infected by ingestion of oocysts from contaminated environment (soil, water and feed) or infected animal tissues postnatally. In the present study, field studies were conducted to evaluate the relationship between soil contamination status of Toxoplasma gondii oocysts and T. gondii infection in pigs in 12 pig farms with different density of cats in central China. The presence of T. gondii oocysts in soil were determined by PCR and loop-mediated isothermal amplification (LAMP). T. gondii DNA was found in 11 farms with different cat density excepting one farm exposed to low cat density. Twenty (21.1%) and 36 (37.9%) of 95 soil samples were T. gondii positive by PCR and LAMP, respectively (0.01<P<0.05). Soil contamination was found with significant difference in statistics between farms with high and low cat density by PCR (0.01<P<0.05), and highly significant differences by LAMP (P<0.01). Additionally, a total of 2277 sera were collected to determine the presence of IgG antibodies against T. gondii using AG-ELISA. Antibodies were found in 453 of 1238 (36.6%) samples from pig farms with high cat density and 220 of 1039 (21.2%) samples from pig farms with low cat density (P<0.01). The results indicated that a high seroprevalence of T. gondii in pigs was found in the pig farms with high soil contamination by T. gondii oocysts in Hubei Province. The soil contamination status of pig farms was significantly influenced by cat density and may be an indicator of T. gondii infection in pigs.

Seroprevalence of Toxoplasma gondii antibodies from slaughter pigs in Chongqing, China

Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii which infects most genera of warm-blooded animals, including humans. The objective of this investigation is to evaluate the seroprevalence of toxoplasmosis in pigs in Chongqing Municipality, southwest China. Slaughterhouse pigs' serum samples collected from six different regions in Chongqing were assayed for T. gondii antibodies by an indirect hemagglutination test. The average seroprevalence of T. gondii were found in 30.6% (278/908) in slaughter pigs, ranging from 21.6% to 40.9% among different sampling sites. The results indicated that toxoplasmosis in swine of Chongqing Municipality was relatively serious, and the pork may be an important source for human infection with T. gondii. Comprehensive measures are needed to strengthen further prevention and control of the disease in Chongqing.

Seroprevalence of Toxoplasma Gondii in Pigs From Southern China

The seroprevalence of toxoplasmosis in pigs was examined in China's southern Guangdong Province from March 2008 through May 2009. A total of 1,022 serum samples was collected from 12 administrative cities and assayed for Toxoplasma gondii antibodies by enzyme-linked immunosorbent assay test. The seroprevalence ranged from 0 to 58.1% and the average T. gondii antibody-positive prevalence was 27.0% (276/1,022), with breeding boars having the highest level at 39.6% (38/96) followed by breeding sows at 36.9% (52/141). The results of the present survey indicate that T. gondii infection is a significant health problem in pigs and represents a public health concern in southern China.

An Outbreak of Lethal Toxoplasmosis in Pigs in the Gansu Province of China

In October 2004, a swine farm in Jinchang, Gansu Province, China, experienced an outbreak of toxoplasmosis. Most of the affected pigs had a rectal temperature greater than 40 degrees C and gradually lost their appetite. Morbidity reached 57%, and mortality was approximately 2%. Analysis of blood samples from affected pigs using hemagglutination inhibition (HI) assay, immunoglobulin G-enzyme-linked immunosorbent assay (IgG-ELISA), and IgM-ELISA tests showed high titers of anti-Toxoplasma gondii antibody. Tachyzoites of T. gondii were found in body fluids of mice inoculated intraperitoneally with ground samples from the heart, liver, spleen, and brain of 2 sick pigs. In addition, the inoculation of 5 pigs with T. gondii tachyzoites caused death in 2 of the pigs. The origin of this outbreak was concluded to be food-borne T. gondii infection.

Seroprevalence of Toxoplasma gondii in pigs in Southwestern China

The seroprevalence of toxoplasmosis in pigs was investigated in Yunnan province, Southwestern China between March 2008 and January 2009. A total of 831 serum samples were collected from 9 counties and assayed for Toxoplasma gondii antibodies by indirect haemagglutination (IHA) test. Antibodies to T. gondii were found in 16.97% (141/831) with slaughter pigs having the highest rate (22.28%), followed by breeding sows (16.59%). The results of the present survey indicated that infection with T. gondii in pigs is widely spread in China, including the Yunnan province, and is of public health concern.

Risk factors for toxoplasmosis in pigs bred in Sicily, Southern Italy

The aim of the study was to determine the seroprevalence of Toxoplasma gondii infection in pigs raised and slaughtered in Sicily, Southern Italy, and to evaluate the risk factors associated with the infection. Samples were collected in seven slaughterhouses and on-site on 274 raising farms across Sicily, in the period from January 2006 until March 2007. For each sampled pig born and raised in Sicily, information was obtained on gender, age, origin, final destination of meat and farm management. Data on the farm included: farming type, presence of cats and dogs, rodent control by rodenticides, cleaning methods, water supply, altitude and herd size. T. gondii-specific antibodies were detected using a commercial Enzyme-Linked Immunosorbent Assay (Institut Pourquier, France).Antibodies against T. gondii were found in 16.3% of Sicilian pigs. The lowest seroprevalence, 7%, was found in the age group 5–7 months (market pig) and the highest, 19%, in the age group >24 months. Risk factors for seropositivity were: age 11–24 months compared to younger (OR 5.62; CI 1.52–20.8); farrow-to-finish farming type (OR 6.85; CI 1.87–25.01) compared to finishing and farrow-to-breed type; less than 50 pigs on the farm (OR 6.8; CI 1.76–26.2); no use of rodenticides (OR 2.71; CI 1.10–6.64), use of water coming from private sources (especially wells; OR 2.8; CI 1.03–7.72).Pigs raised in Sicily shows a high prevalence of antibodies against T. gondii. Pre-harvesting interventions to lower the risk of locally produced meat consumption for consumers should point as soon as possible to increase hygienic condition on the farm, by carefully removing waste with automatic cleaning and reducing biohazard by rodent control. Consumers must receive information on the correct handling and cooking locally produced pork meat derivatives.

Endemic Toxoplasmosis in Pigs on a Farm in Maryland: Isolation and Genetic Characterization of Toxoplasma gondii

The prevalence of Toxoplasma gondii was investigated on a poorly managed pig farm in Maryland. Serum and tissue samples from 48 of the 100 pigs on the farm were available for T. gondii evaluation. Serological testing was performed using both ELISA and the modified agglutination test (MAT). Antibodies to T. gondii were detected by ELISA in 12 of 48 animals, while antibodies were detected in 34 of 48 pigs by MAT with titers of 1:10 in 1, 1:20 in 4, 1:40 in 7, 1:80 in 3, 1:160 in 8, 1:320 in 3, 1:640 in 4, and 1:1,280 in 4. Hearts of 16 pigs with MAT titers of 1:10 or higher were bioassayed for T. gondii in cats; 11 cats shed T. gondii oocysts. Hearts of 22 pigs were autolyzed and bioassayed only in mice; T. gondii was isolated from 3 of these 22 pigs. Genetic typing of the 14 T. gondii isolates using the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico loci revealed 4 genotypes; 10 isolates belonged to type II lineage (genotypes 1 and 2), 3 belonged to genotype 3, and 1 belonged to genotype 4. Genotype 1 and 2 have type II alleles at all genetic loci, except the former has type II allele and the latter has a type I allele at locus Apico. Both genotypes 1 and 2 are considered to belong to the clonal type II lineages. Genotype 3 and 4 are nonclonal isolates. Results document high prevalence of T. gondii in pigs on a farm in Maryland.

Toxoplasma gondii: estudo soro-epidemiológico de suínos da região Sudoeste do Estado do Paraná

Avaliou-se a soroprevalência da toxoplasmose em suínos criados e abatidos para consumo humano, por meio da freqüência de anticorpos da classe IgG anti-Toxoplasma gondii em 408 animais provenientes de plantéis de 25 municípios da região Sudoeste do Estado do Paraná, Brasil. As amostras de soro foram examinadas por meio da reação de imunofluorescência indireta (RIFI). Foi encontrada a freqüência de 25,5% de soros positivos, com diluições iguais ou superiores a 1:64. Não foram observadas diferenças estatisticamente significativas quanto a sexo e a idade dos animais. O maior título observado foi de 4.096 (3,0%) e o mais freqüente foi 64 (74%) sugerindo que uma infecção crônica estava ocorrendo na população. A alta prevalência da infecção encontrada nos rebanhos suínos estudados sugere que estes possam servir de fonte de infecção para os consumidores que têm o hábito de consumir carne suína crua ou mal cozida.