Diagnosis of Swine Toxoplasmosis by PCR and Genotyping of Toxoplasma gondii from pigs in Henan, Central China

Abstract

Background Toxoplasma gondii, a widely prevalent protozoan parasite, causes serious toxoplasmosis infections in humans and other animals. Among livestock, pigs are susceptible to T. gondii infection. Despite Henan being one of the biggest pig-raising provinces in China, little information exists on the epidemiology of toxoplasmosis in this location. Therefore, we molecularly characterized DNA samples from pigs in Henan. A total of 1647 samples, including 952 from dead piglets, 478 from seriously sick fattening pigs and 217 from abortion sows, were collected from different animal hospitals or pig farms from 10 different cities in Henan (2006–2008). Each pig corresponded to a separate pig farm. DNA was extracted from 3 to 5 g of the most severely affected pig tissue (liver, spleen, lung, hilar lymph nodes and amniotic fluid) after postmortem examination. The presence of the T. gondii B1 gene was detected using nested polymerase chain reactions (PCR). Genotyping was performed directly on DNA from the PCR-positive tissue samples using 11 PCR restriction fragment length polymorphism markers (SAG1, 5′- and 3′-SAG2, alternative SAG2, SAG3, BTUB, GRA6, L358, PK1, c22–8, c29–2, and Apico).ResultsOf all samples, thirty-four were positive for the T. gondii B1 gene (2.06%, 95% CI: 1.86%–2.26%) from four cities, including 31 from NanYang city, one (PgXY 1) from Xinyang City, one (PgZZ 1) from Zhengzhou City and one (PgZK1) from Zhoukou City. The prevalence was found to be highest in piglets than in fattening pigs and sows. And the difference was statistically significant (P<0.01). The following 32 samples were genotyped with complete data: 13 hilar lymph node tissue samples, seven liver tissue samples, seven lung tissue samples, four spleen tissue samples, and one amniotic fluid sample. Only one genotype, belonging to ToxoDB Genotype #9, was identified.ConclusionsThis is the first large-scale survey molecularly characterizing T. gondii from pigs in Henan. The results of the present study revealed that T. gondii infection is present in swine in Henan and is a potential source of foodborne toxoplasmosis in the investigated areas. Implementation of effective control measures for T. gondii to reduce the chance of zoonotic toxoplasmosis spreading from pig farms may be warranted. The results show that the ToxoDB #9 genotype may be the dominant T. gondii lineage in mainland China. These findings strengthen the limited Chinese T. gondii epidemiology database.

Low prevalence of Toxoplasma gondii in pork from slaughter houses in the central of China

“…In this study, isolating T. gondii DNA from the homogenate of a large meat samples (50 gram or 5 gram meat for one swine) rather than using a small sample would increase PCR sensitivity. However, T. gondii DNA was not detected in the pork digestion fluids during this survey (81 tissue homogenate, which came from 2090 swine), which is less than our previously survey (2.06%, 34/1647) from tissue samples in Henan province by T. gondii B1 gene [21]. Our result indicated that the relative low density of T. gondii parasites in pork.…”

Low prevalence of antibodies against Toxoplasma gondii in dairy cattle from China’s central region

“…The dominant T. gondii genotype in China is ToxoDB#9 [ 38 ]. Several studies have identified T. gondii ToxoDB#9 in swine, domestic cats, and sheep in Henan Province [ 21 , 23 , 24 , 39 , 40 ]. However, only ToxoDB#225 T. gondii has been identified in Chinese cattle [ 40 ].…”

Occurrence and genetic characterization of Toxoplasma gondii and Neospora caninum in slaughtered domestic rabbits in central China

“…In this study, only 1 out of 13 T. gondii- positive samples gave complete genotyping results at all 11 gene loci, and was identified to ToxoDB genotype #9, and two samples were genotyped at four and two genetic loci, respectively (Table 2). In China, ToxoDB genotype #9 is a predominant genotype, and has been found previously in a number of hosts in different regions including Henan Province [16, 23]. However, data on the genetic characterization of rabbit-derived T. gondii isolates in China are limited.…”