Seroprevalence of Toxoplasma gondii infection in pet dogs in Lanzhou, Northwest China

Detection of antibodies to Toxoplasma gondii among owned dogs in Cambodia

Toxoplasma gondii is a protozoan parasite belonging to the phylum Apicomplexa, which has a two-host life cycle and an extensive global distribution. The presence of antibodies to T. gondii was examined in owned dogs in Cambodia. In total, 103 dog serum samples from 37 households in northern Cambodia were collected and examined for evidence of T. gondii infection using an indirect immunofluorescent antibody test. In total, 52 of 103 (50.5%) samples were serologically positive for T. gondii in this study. No significant risk factor associated with T. gondii infection was found. To the best of our knowledge, this is the first report of the seroprevalence of T. gondii in dogs from Cambodia, which revealed a considerable risk of infection for humans. Therefore, consuming undercooked dog meat or contacting feces with contaminated cat feces should be restricted to avoid the possibility of zoonosis. Further studies are needed to determine the epidemiology of T. gondii in populations of larger dogs and other animals to improve our understanding of the situation of the pathogen in this country.

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First report of T. gondii infection in dogs from Cambodia

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Adult dogs are more likely to be infected with the pathogen (T. gondii) at higher antibody concentration.

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Consumption of undercooked dog meat or contact with cat feces maybe potential risks for human T. gondii infection in Cambodia.

Seroprevalence of Toxoplasma gondii Infection in Pet Dogs in Anhui Province, China

Background:

Toxoplasma gondii is an obligate intracellular parasite, which can infect all nucleated cells in a variety of vertebrate animals, including human, causing toxoplasmosis. Although a number of studies have reported on the seroprevalence of T. gondii infection in dogs in China, however, information about T. gondii infection in pet dogs in Anhui, China is not available.

Methods:

The modified agglutination test (MAT) was used to detect antibodies in sera samples from 468 pet dogs at Anhui Province in China from November 2013 to April 2017.

Results:

18.6% animals were T. gondii seropositive, indicating a slightly higher prevalence of T. gondii infection in pet dogs in Anhui, China in comparison with other provinces in China.

Conclusion:

Our present study provided epidemiological data on T. gondii seroprevalence in pet dogs in Anhui, China for the effective prevention and control of the parasite prevalence in this area.

Prevalence of Toxoplasma gondii Antibodies in Stray Dogs from Various Locations in West and East Malaysia

Toxoplasmosis is caused by an obligate intracellular protozoan parasite; Toxoplasma gondii, which is one of the most important zoonotic parasite worldwide. In dogs, the sexual reproductive cycle of T. gondii is lacking, and the animals are not widely consumed as food, but they are vital in the mechanical transmission of the parasite. However, there is no present data on the exposure of stray dogs to T. gondii in Malaysia. The objective of this serological survey was to determine the prevalence of T. gondii antibodies (IgG) and associated factors in stray dogs in East and West Malaysia. Antibodies to T. gondii were determined in serum samples from 222 stray dogs from 6 different states in East and West Malaysia (Peninsular Malaysia) using an Indirect ELISA. The seroprevalence for T. gondii was 23.4% (Confidence interval: CI 17.8-29.2%). Stray dogs from Selangor and Kuala Lumpur had the highest seroprevalence (32.4%; CI 13.2-45.5%) and lowest in those from Penang and Kedah (12.5%; CI 1.3-23.5%). Gender and breed were not associated with T. gondii seropositivity. However, adult dogs were more likely to be seropositive for T. gondii (OR=2.89; CI 1.1-7.7) compared with younger dogs. These results revealed that T. gondii is prevalent in stray dogs in the studied areas in Malaysia, and indicative of the level of environmental contamination of this parasite especially in urban areas.

Toxoplasma gondii infections in dogs: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, and genetic diversity of T. gondii in dogs (Canis familiaris) from 2009-2020. Seroprevalence estimates of T. gondii worldwide were tabulated. Reports of high seroprevalence in canine population and high congenital transmission of T. gondii in dogs in Brazil are reviewed. Most reports from China were published in Chinese, and these reports are now summarized here. Dogs have an additional importance in some countries such as China, Vietnam, and Nigeria; whereas in many cities dog meat is sold commercially for human consumption and given to felids, and transmission of T. gondii could occur if meat is not cooked properly. Dogs can ingest T. gondii-infected cat feces and these oocysts remain viable after passage through the digestive tract of the dog; T. gondii DNA was found in feces of dogs from New York City parks in USA. Most clinical canine cases of toxoplasmosis were in immunosuppressed dogs, and ulcerative dermatitis was one of the main presentations. Genetic diversity based on PCR-RFLP markers using DNA derived from 133 viable T. gondii isolates from dogs from several countries is discussed. T. gondii strains from Asia and Americas were more genetically diverse than those from Africa. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Risk factors associated to Toxoplasma gondii infection in dairy farms in Hamedan suburb, Iran

Toxoplasmosis is a zoonotic food-borne disease with global distribution. The principal aim of this research was to detect the seroprevalence of T. gondii infection in cattle, dogs and cats in dairy farms with high incidence of abortion, as well as to identify associated risk factors in Hamedan, Iran. A number of four large dairy farms with high history of abortion were selected and evaluated for risk factors associated to T. gondii infection. Blood samples were taken from 400 of pregnant cattle, 85 of dogs and 35 of cats (all of the dogs and cats population from interring and around of farms were sampled). The samples were examined for presence of antibodies to T. gondii infection using ELISA technique. Seroprevalence of T. gondii infection were detected 13% in cattle, 47.1% in dogs and 40% in cats. With regard to cattle seropositivity and associated risk factors, significant differences were found regarding abortion history (P = 0.026), race (P = 0.035), rodents' presence in farm (P = 0.006) and age groups (P = 0.011). Also, there were no significant differences between seroprevalence rate and stage of gestation (P = 0.998), type of breeding service (P = 0.561), stillbirth history (P = 0.302), dog contact with herd (P = 0.302) as well as poultry presence in the farm (P = 0.302). In both dogs and cats, the seroprevalence rate for females was higher than males (P < 0.05); also, no significant differences were seen in age groups (P > 0.05). This is the comprehensive evaluation of risk factors associated to toxoplasmosis in Iranian dairy farms at the first time. Our finding indicated that toxoplasmosis may partly be responsible for transmission to humans and also abortion and economic losses in dairy farms. Improve the sanitary strategies for reducing the risk factors in animals' husbandry and launching control programs are recommended.

First molecular detection of Toxoplasma gondii in vegetable samples in China using qualitative, quantitative real-time PCR and multilocus genotyping

Toxoplasma gondii infection is becoming increasing problem in China but there is no data concerning contamination of vegetables intended for consumption with this parasite. The aim of the present study was to investigate fresh vegetables originated from open markets located in the Xining City, the Qinghai-Tibet Plateau (QTP), P.R. China for their contamination with T. gondii. A total of 279 fresh vegetable samples were collected and analysed using real-time PCR assay targeting B1 gene and multilocus genotyping. T. gondii DNA was found in 10 (3.6%) samples tested; eight of them represented T. gondii type I and remaining two T. gondii type II. The approximate level of contamination of positive vegetables samples, estimated based on quantitative real-time PCR (qPCR), ranged between less than one and 27000 T. gondii oocysts per sample, with majority not exceeding several oocysts per sample. The results of the study confirmed that T. gondii is present in vegetables offered in open markets in the Qinghai province, P.R. China; eating them unwashed and raw may therefore pose a threat to consumers. This is the first investigation describing T. gondii detection in fresh vegetables intended for consumption collected from the territory of P.R. China using sensitive molecular tools.

Seroprevalence and risk factors of Toxoplasma gondii infection in rabbit of local Algerian population

AIM

The objective of this investigation was to determine the seroprevalence and identify the risk factors of Toxoplasma gondii infection in the rabbit of the local Algerian population from five districts of Northern Algeria.

MATERIALS AND METHODS

Blood samples of 350 rabbits were collected and analyzed for the presence of anti-T. gondii immunoglobulin G antibodies using the indirect enzyme-linked immunosorbent assay. Additional data concerning the farms and management practices were obtained through a questionnaire used in surveys and interviews.

RESULTS

The overall seroprevalence was 14.6% (51/350). The seroprevalence was significantly higher in outdoor rearing farms and was linked to the presence of animals from other species on the farm. A higher seroprevalence was found in older animals compared to younger ones. No difference in seroprevalence was noted with respect to the origin or gender of animals, type of cage, feed and water sources, presence of cats in the vicinity, hygiene status, or season.

CONCLUSION

This study has shown that T. gondii prevalence in rabbits of the local population is relevant and may have important implications for public health in rural areas.

The Seroprevalence and Risk Factors of Toxoplasmosis Among Female Undergraduate University Students in Saudi Arabia

Objectives

Toxoplasma gondii (T. gondii) is a serious public health issue, but limited data has been published to date on the seroprevalence of T. gondii infection in Saudi Arabia. Therefore, this study aimed to establish the seroprevalence and risk factors of T. gondii infection using a sample of females enrolled at a university in Northern Saudi Arabia.

Methods

Using a cross-sectional research approach, we recruited a convenience sample of 180 healthy females studying at the University of Tabuk between February and June 2016. We used a questionnaire to gather sociodemographic data on the participants to establish the risk factors leading to exposure to toxoplasma. Blood samples were taken from the participants and analyzed to detect T. gondii antibodies (immunoglobulin M and immunoglobulin G) via the enzyme-linked immunosorbent assay technique. Multivariate logistic regression modeling was employed to establish the potential predictor variables for T. gondii infection.

Results

Of the 180 participants, 17 (9.4%) were seropositive for T. gondii IgG. None tested positive for IgM antibodies exclusively. The sole variable positively associated with seropositive T. gondii IgG was the participants' consumption of raw, unwashed fruit or vegetables (odds ratio = 3.36, 95% confidence interval: 1.11-10.22).

Conclusions

Our findings emphasize the need for higher awareness of toxoplasmosis in Saudi Arabia, specifically knowledge of the way toxoplasma infection occurs so that women can more easily avoid it. Large-scale research is therefore required to inform the design of future public health interventions.

Sixty Years (1957-2017) of Research on Toxoplasmosis in China-An Overview

Toxoplasma gondii is a ubiquitous zoonotic pathogen belonging to apicomplexan parasites. Infection in humans and animals may cause abortion and other severe symptoms under certain circumstances, leading to great economical losses and public health problems. T. gondii was first discovered in China in 1955 and the corresponding work was published in 1957. Since then, a lot of work has been done on this parasite and the diseases it causes. This review summarizes the major progress made by Chinese scientists over the last 60 years, and gives our perspectives on what should be done in the near future. A wide variety of diagnostic approaches were designed, including the ones to detect T. gondii specific antibodies in host sera, and T. gondii specific antigens or DNA in tissue and environmental samples. Further work will be needed to translate some of the laboratory assays into reliable products for clinic uses. Epidemiological studies were extensively done in China and the sero-prevalence in humans increased over the years, but is still below the world average, likely due to the unique eating and cooking habits. Infection rates were shown to be fairly high in meat producing animals such as, pigs, sheep, and chickens, as well as in the definitive host cats. Numerous subunit vaccines in the form of recombinant proteins or DNA vaccines were developed, but none of them is satisfactory in the current form. Live attenuated parasites using genetically modified strains may be a better option for vaccine design. The strains isolated from China are dominated by the ToxoDB #9 genotype, but it likely contains multiple subtypes since different ToxoDB #9 strains exhibited phenotypic differences. Further studies are needed to understand the general biology, as well as the unique features of strains prevalent in China.

Risk factors of Toxoplasma gondii infection in hunting, pet and watchdogs from southern Spain and northern Africa

Dogs can act as reservoirs of Toxoplasma gondii infections for humans and other hosts. Here we determined seroprevalence and risk factors of T. gondii infection in dogs from Andalusia (Southern Spain) and Ceuta (Northern Africa). Antibodies to T. gondii were detected in 235 out of 769 dogs (30.6%; CI95%: 27.3-33.8) by the modified agglutination test (MAT, cut-off of 1:25) with titers of 1:25 in 91, 1:50 in 43, 1:100 in 84, and ≥1:500 in 17 dogs. The main risk factors associated with T. gondii infection in dogs were age (higher seroprevalence in older dogs), hunter activity and size (higher seroprevalence in larger and medium dogs). This is the first study on T. gondii infection in pet dogs from Spain and Ceuta. The results indicate that T. gondii is widespread in dogs in mainland Spain and Ceuta, which might have important implications for public health.

Pseudomonas sp. LZ-Q continuously degrades phenanthrene under hypersaline and hyperalkaline condition in a membrane bioreactor system

Graphical Abstract

Abstract

Phenanthrene is one of the most recalcitrant components of crude oil-contaminated wastewater. An efficient phenanthrene-degrading bacterium Pseudomonas sp. strain named LZ-Q was isolated from oil-contaminated soil near the sewage outlet of a petrochemical company. Pseudomonas sp. LZ-Q is able to degrade 1000 mg/L phenanthrene in Bushnell-Hass mineral salt medium. It also degrades other polycyclic aromatic hydrocarbons such as naphthalene, anthracene, pyrene, petrol, and diesel at broad ranges of salinities of 5 g/L to 75 g/L, pHs of 5.0–10.0, and temperatures of 10–42 °C. Therefore, Pseudomonas sp. LZ-Q could be a good candidate for remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated wastewater. A membrane bioreactor (MBR) was applied to investigate the remediation ability of the strain LZ-Q. Wastewater containing phenanthrene with pH of 8, salinity of 35 g/L, and COD of 500 mg/L was continuously added to the system (HRT = 3 h). Results showed that Pseudomonas sp. LZ-Q is capable of degrading 96% of 20 mg/L phenanthrene and 94% of 500 mg/L COD for 60 days in a continuous mode. These results showed that the MBR system with strain LZ-Q might be a good approach for PAHs’ remediation in industrial wastewaters.

Seroprevalence and associated risk factors of Toxoplasma gondii infection in the Korean, Manchu, Mongol and Han ethnic groups in eastern and northeastern China

A cross-sectional study was conducted from June 2013 to August 2015 to determine the seroprevalence and possible risk factors for humanToxoplasma gondiiinfection in Korean, Manchu, Mongol and Han ethnic groups in eastern and northeastern China. A total of 1842 serum samples, including Han (n= 802), Korean (n= 520), Manchu (n= 303) and Mongol (n= 217) groups, were analysed using enzyme-linked immunoassays to detect IgG and IgMT. gondiiantibodies. The overallT. gondiiIgG and IgM seroprevalences were 13·79% and 1·25%, respectively. Of these groups, Mongol ethnicity had the highestT. gondiiseroprevalence (20·74%, 45/217), followed by Korean ethnicity (16·54%, 86/520), Manchu ethnicity (13·86%, 42/303) and Han ethnicity (11·35%, 98/802). Multiple analysis showed that the consumption of raw vegetables and fruits, the consumption of raw/undercooked meat and the source of drinking water were significantly associated withT. gondiiinfection in the Han group. Likewise, having a cat at home was identified as being associated withT. gondiiinfection in the Korean, Manchu and Mongol groups. Moreover, the consumption of raw/undercooked meat was identified as another predictor ofT. gondiiseropositivity in the Mongol group. The results of this survey indicate thatT. gondiiinfection is prevalent in Korean, Manchu, Mongol and Han ethnic groups in the study region. Therefore, it is essential to implement integrated strategies with efficient management measures to prevent and controlT. gondiiinfection in this region of China. Moreover, this is the first report ofT. gondiiinfection in Korean, Manchu, and Mongol ethnic groups in eastern and northeastern China.

Toxoplasma gondii Infection in Pregnant Women: A Seroprevalence and Case-Control Study in Eastern China

Very limited information is available concerning the epidemiology of T. gondii infection in pregnant women in eastern China. Therefore, a case-control study was conducted to estimate the seroprevalence of toxoplasmosis in this population group and to identify risk factors and possible routes of contamination. Serum samples were collected from 965 pregnant women and 965 age-matched nonpregnant control subjects in Qingdao and Weihai between October 2011 and July 2013. These were screened with enzyme linked immunoassays for the presence of anti-Toxoplasma IgG and anti-Toxoplasma IgM antibodies. 147 (15.2%) pregnant women and 167 (17.3%) control subjects were positive for anti-T. gondii IgG antibodies, while 28 (2.9%) pregnant women and 37 (3.8%) controls were positive for anti-T. gondii IgM antibodies (P = 0.256). There was no significant difference between pregnant women and nonpregnant controls with regard to the seroprevalence of either anti-T. gondii IgG or IgM antibodies. Multivariate analysis showed that T. gondii infection was associated with location, cats in home, contact with cats and dogs, and exposure to soil. The results indicated that the seroprevalence of T. gondii infection in pregnant women is high compared to most other regions of China and other East Asian countries with similar climatic conditions.

Prevalence of Toxoplasma gondii in Dogs in Zhanjiang, Southern China

Toxoplasmosis, caused by Toxoplasma gondii, is a parasitic zoonosis with worldwide distribution. The present study investigated the prevalence of T. gondii in dogs in Zhanjiang city, southern China, using both serological and molecular detection. A total of 364 serum samples and 432 liver tissue samples were collected from the slaughter house between December 2012 and January 2013 and were examined for T. gondii IgG antibody by ELISA and T. gondii DNA by semi-nested PCR based on B1 gene, respectively. The overall seroprevalence of T. gondii IgG antibody was 51.9%, and T. gondii DNA was detected in 37 of 432 (8.6%) liver tissue samples. These positive DNA samples were analyzed by PCR-RFLP at 3'- and 5'-SAG2. Only 8 samples gave the PCR-RFLP data, and they were all classified as type I, which may suggest that the T. gondii isolates from dogs in Zhanjiang city may represent type I or type I variant. This study revealed the high prevalence of T. gondii infection in dogs in Zhanjiang city, southern China. Integrated measures should be taken to prevent and control toxoplasmosis in dogs in this area for public health concern.

Seroprevalence and genotype of Toxoplasma gondii in pigs, dogs and cats from Guizhou province, Southwest China

BACKGROUND

Toxoplasma gondii is an obligate, intracellular protozoan that infects almost all warm-blooded animals, including humans, domesticated and wild animals. Recent studies of Toxoplasma gondii isolates from animals in different regions of China have shown a limited genetic diversity with the dominance of the ToxoDB PCR-RFLP genotype #9 named as "Chinese 1". However, there is not much published information regarding its prevalence in domestic animals from Guizhou province, a subtropical region in Southwest China. The objectives of this study were to determine seroprevalence and genetic diversity of T .gondii in pigs, dogs and cats in Guizhou province, Southwest China.

FINDINGS

The anti-T. gondii IgG were detected in 70.0%(49/70) pigs, 20.56%(22/107) dogs and 63.16(12/19) cats. The anti-T. gondii IgM were found in 0.93%(1/107) dogs, 21.53%(4/19) cats, but not in pigs. In addition, the toxoplasma circulating antigen (CAG) were detected in 16.9%18/70)pigs, 13.1% (14/107) dogs and 10.5%(2/19) cats. The T. gondii DNA were detected in 31.5%(22/70) pigs, 3.7%(4/107) dogs and 52.63%(10/19) cats. Five T. gondii isolates were obtained(3 from pigs and 2 from cats). The genotype of these five isolates belonged to the predominant genotype "Chinese 1".

CONCLUSIONS

The high prevalence of T. gondii infection in pigs,cats and dogs indicated that the T. gondii infection is common in Guizhou province. Additionally, the T. gondii genotype "Chinese 1" was dominant in Southwest China.

Prevalence and genetic characterization of Toxoplasma gondii in pet dogs in Central China

The prevalence and genotype of Toxoplasma gondii infection in dogs in Henan Province, Central China was investigated. A total of 125 blood samples were collected from pet dogs during April to June 2013, and all samples were examined by indirect hemagglutination antibody test (IHA) and nested PCR. The overall T. gondii prevalence in pet dogs was 24.0% (30/125), with 20.8% (26/125) in IHA and 10.4% (13/125) in PCR, respectively. No statistical associations were found between animal gender and age and the prevalence of T. gondii infection. Thirteen positive DNA samples were genotyped using 11 PCR-RFLP markers, including SAG1, (3'+5') SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. Of these, only 2 samples were genotyped with complete data for all loci, and a novel genotype (type III at SAG3 and GRA6 loci, and type I at other loci) was identified. This is the first report of genetic characterization of T. gondii infection in dogs in China.

Low prevalence of Neospora caninum and Toxoplasma gondii antibodies in dogs in Jilin, Henan and Anhui Provinces of the People's Republic of China

BACKGROUND

Neospora caninum and Toxoplasma gondii are important pathogens of worldwide distribution. N. caninum is a major cause of abortion in cattle and dogs are main reservoirs because they excrete the environmentally resistant oocysts. Toxoplasmosis is a worldwide zoonosis and dogs are considered as sentinels for this parasite because of their close contact with people and cats; additionally dog meat is also used for human consumption in China. The aim of the present study was to assess the prevalence of N. caninum and T. gondii infection in dogs from China. A total of 425 countryside dog hearts in Jilin, Henan and Anhui provinces of the People's Republic of China were collected from slaughter houses in two batches; the first batch of 96 in October 2013, and the second batch of 329 in April 2014. Serum samples extracted from 96 dog hearts were tested for antibodies to N. caninum and from 425 dog hearts were tested for T. gondii antibodies in the modified agglutination tests (cut-off 1:25 for both), using respective antigens.

RESULTS

Antibodies to N. caninum were 6 of 96 (6.25%) of dogs with titers of 1:25 in 2, 1:50 in 3, and 1:100 in 1. All seropositive dogs were more than 1 year old. Antibodies to T. gondii were found in 35 of 425 (8.24%) dogs with titers of 1:25 in 15, 1:50 in 14; and 1:100 in 6.

CONCLUSION

The results of the present study indicated low prevalence of N. caninum and T. gondii antibodies in dogs of China, compared with Europe and America. Identification of the risk factors that underlie these differences may help prevention of neosporosis and toxoplasmosis. This is the first report of N. caninum infection in dogs from China.

Detection of Toxoplasma gondii oocysts in soils in northwestern China using a new semi-nested PCR assay

BACKGROUND

Toxoplasma gondii is a zoonotic pathogen that can infect a range of animals and humans. Ingestion of T. gondii oocysts in soil is a significant transmission route for humans and animals acquiring toxoplasmosis. In the present study, we developed a new semi-nested PCR method to determine T. gondii oocysts distribution in soils in northwestern China.

RESULTS

The one tube semi-nested PCR assay was developed to detect the oocysts of T. gondii in soil, targeting the repetitive 529 bp fragment of T. gondii genomic DNA. Then a total of 268 soil samples, including 148 samples from Gansu Province and 120 samples from Qinghai Province, northwestern China, were examined by the semi-nested PCR method. One third of the positive samples were sequenced. The sensitivity of the semi-nested PCR assay was 10(2)  T. gondii oocysts in 5 g soil sample. Investigation of soil samples from northwestern China showed that 34 out of 268 soil samples (12.69%) were T. gondii positive. Sequences of the partial 529 bp fragments varied from 0-1.2% among the sequenced samples. The prevalence of T. gondii oocysts in soil from cities (24/163) was slightly higher than that in soils from pasturing areas (10/105) (P = 0.21). Among the different regions in cities, the prevalence of T. gondii oocysts in soils from parks was 14.15%, whereas that in soils from schools was 19.05%.

CONCLUSIONS

The present study firstly reported the prevalence of T. gondii oocysts in soils in northwest China using a novel semi-nested PCR assay, which provided baseline data for the effective prevention and control of toxoplasmosis in this region.

Evaluation of recombinant granule antigens GRA1 and GRA7 for serodiagnosis of Toxoplasma gondii infection in dogs

Background

Toxoplasmosis, caused by the obligate intracellular parasite Toxoplasma gondii, is an important zoonotic disease worldwide. The precise detection of T. gondii infection in dogs has important public health significance. In this study, recombinant granule antigen proteins GRA1 and GRA7 were evaluated as potential diagnostic markers for T. gondii infection in dogs by an indirect enzyme-linked immunosorbent assay (ELISA).

Results

GRA1 and GRA7 were cloned and expressed in Escherichia coli, and the recombinant GRA1, GRA7- and Toxoplasma lysate antigen (TLA)-based ELISAs were developed and evaluated using the canine positive and negative serum samples for anti-T. gondii antibodies determined by modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT), showing a seroprevalence of 15.1% by TLA- and GRA1-ELISA, and 15.8% by GRA7-ELISA, and no significant difference was observed (P > 0.05). When compared with the two reference assays, MAT and IFAT, the GRA7-ELISA showed the highest co-positivity and co-negativity rates. Receiver operating characteristic (ROC) analysis revealed a largest area under curve (AUC) of 0.973 (95% CI, 0.955 to 0.991), and a highest relative sensitivity (93.2%) and specificity (94.0%) for a cut-off value of 0.809 in GRA7-ELISA.

Conclusions

The results of the present study showed that GRA7-ELISA is highly sensitive and specific, and GRA7 is a potential serodiagnostic marker for the detection of T. gondii infection in dogs.

Seroprevalence of Toxoplasma gondii infection in police dogs in Shenyang, Northeastern China

In recent years, worldwide surveys of Toxoplasma gondii infection in dogs have been reported. However, only limited surveys of T. gondii infection in police dogs have been available, including China. In the present study, we report the seroprevalence of T. gondii in police dogs in Shenyang, northeastern China. Sera from 291 police dogs were examined for T. gondii antibodies with the modified agglutination test (MAT), and 30.9% animals were tested seropositive. The results of the present study indicated a relatively high prevalence of T. gondii infection in police dogs in Shenyang, China.

Prevalence and genetic characterization of Toxoplasma gondii in house sparrows (Passer domesticus) in Lanzhou, China

The prevalence of Toxoplasma gondii infection in birds has epidemiological significance because birds are indeed considered as a good indicator of environmental contamination by T. gondii oocysts. In this study, the prevalence of T. gondii in 313 house sparrows in Lanzhou, northwestern China was assayed by the modified agglutination test (MAT). Antibodies to T. gondii were positive in 39 (12.46%) of 313 samples (MAT titer ≥ 1:5). Tissues of heart, brain, and lung from the 39 seropositive house sparrows were tested for T. gondii DNA, 11 of which were found to be positive for the T. gondii B1 gene by PCR amplification. These positive DNA samples were typed at 9 genetic markers, including 8 nuclear loci, i.e., SAG1, 5'- and 3'-SAG2, alternative SAG2, SAG3, GRA6, L358, PK1, c22-8 and an apicoplast locus Apico. Of them, 4 isolates were genotyped with complete data for all loci, and 2 genotypes (Type II variants; ToxoDB #3 and a new genotype) were identified. These results showed that there is a potential risk for human infection with T. gondii in this region. To our knowledge, this is the first report of T. gondii seroprevalence in house sparrows in China.

Seroprevalence of Toxoplasma gondii in slaughtered horses and donkeys in Liaoning province, northeastern China

Background

Toxoplasma gondii is an important zoonotic pathogen infecting humans and almost all warm-blooded animals. The most common sources of human infection are ingestion of tissue cysts in raw or undercooked meat. However, limited information is available about T. gondii infection in horses and donkeys in China. In the present study, we report the seroprevalence of T. gondii infection in horses and donkeys in Liaoning province, northeastern China.

Methods

Serum samples were collected from 711 and 738 slaughtered horses and donkeys, respectively, in 13 regions of Liaoning province. The modified agglutination test (MAT) was used to test the specific antibodies to T. gondii.

Results

In this study, 178 of 711 (25.0%) horses were seropositive for T. gondii with titers of 1:25 in 81, 1:50 in 62, 1:100 in 33, and 1:200 in 2, and seroprevalence of T. gondii infection from 13 regions ranged from 8.2% to 37.0%. Antibodies to T. gondii were found in 174 of 738 (23.6%) donkeys with titers of 1:25 in 66, 1:50 in 54, 1:100 in 49, and 1:200 in 5, and seroprevalence varied in 13 different regions, ranging from 9.1% to 32.6%.

Conclusions

The results of the present study indicated that the rate of infection with T. gondii in horses and donkeys is a little high in Liaoning province, northeastern China in comparison to other surveys in China, which suggests that consumption of horse and donkey meat in this area may represent a potential source for human infection with T. gondii.

Serological evidence of Toxoplasma gondii infection in five species of bats in China

Toxoplasma gondii is an obligate intracellular protozoan parasite that can infect almost all warm-blooded animals and humans with a worldwide distribution. Bats are reservoirs for an increasing number of emerging zoonotic viruses, such as henipaviruses and severe acute respiratory syndrome coronavirus (SARS-CoV). However, little is known of T. gondii infection in bats. The objective of the present study was to determine the seroprevalence of T. gondii infection in bats in China. A total of 217 serum samples from 5 species of bats were collected between April, 2010, and August, 2011, from 4 provinces in China. Antibodies to T. gondii were determined using the modified agglutination test (MAT, 1:25 or higher). Antibodies to T. gondii were found in 26.5% (18/68) Megaderma lyra, 13.6% (12/88) Rousettus leschenaulti, 13.6% (3/22) Cynopterus sphinx, 20% (4/20) Vespertilio superaus, and 15.8% (3/19) Pipistrellus javanicus. Antibody titers ranged from 1:25 to 1:400, with titers of 1:200 detected in 4 of the 5 bat species. The present study suggests the likely occurrence of T. gondii infection in bats in China, and these bats are new putative hosts for T. gondii, which may pose a threat to human health.

Toxoplasmosis and Polygenic Disease Susceptibility Genes: Extensive Toxoplasma gondii Host/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders

Toxoplasma gondii is not only implicated in schizophrenia and related disorders, but also in Alzheimer's or Parkinson's disease, cancer, cardiac myopathies, and autoimmune disorders. During its life cycle, the pathogen interacts with ~3000 host genes or proteins. Susceptibility genes for multiple sclerosis, Alzheimer's disease, schizophrenia, bipolar disorder, depression, childhood obesity, Parkinson's disease, attention deficit hyperactivity disorder (P  from  8.01E - 05  (ADHD)  to  1.22E - 71) (multiple sclerosis), and autism (P = 0.013), but not anorexia or chronic fatigue are highly enriched in the human arm of this interactome and 18 (ADHD) to 33% (MS) of the susceptibility genes relate to it. The signalling pathways involved in the susceptibility gene/interactome overlaps are relatively specific and relevant to each disease suggesting a means whereby susceptibility genes could orient the attentions of a single pathogen towards disruption of the specific pathways that together contribute (positively or negatively) to the endophenotypes of different diseases. Conditional protein knockdown, orchestrated by T. gondii proteins or antibodies binding to those of the host (pathogen derived autoimmunity) and metabolite exchange, may contribute to this disruption. Susceptibility genes may thus be related to the causes and influencers of disease, rather than (and as well as) to the disease itself.

Seroprevalence of Toxoplasma gondii infection in slaughtered chickens, ducks, and geese in Shenyang, northeastern China

Background

In recent years, investigations of Toxoplasma gondii infection in poultry (chickens, ducks, and geese) have been reported worldwide, including China. However, little is known about the prevalence of T. gondii infection in poultry in northeastern China. Therefore, the present study was performed to determine the prevalence of T. gondii infection in slaughtered chickens, ducks, and geese in Shenyang, northeastern China.

Methods

In the present study, the seroprevalence of T. gondii in 502 adult chickens, 268 adult ducks, and 128 adult geese was surveyed using the modified agglutination test (MAT).

Results

The seroprevalences of T. gondii were 5.8%, 7.8%, and 4.7% in chickens, ducks, and geese, respectively. Prevalence was higher in free-range groups (11.2%, 12.3%, and 8.9%) than caged groups (4.7%, 7.5%, and 6.0%), and there was a statistically significant difference only between free-range chickens and caged chickens, but no significant difference was found between free-range ducks, geese and caged ducks, geese.

Conclusions

The present study shows the prescence of T. gondii infection in slaughtered chickens, ducks, and geese in Shenyang, northeastern China, which suggests that consumption of poultry meat in Shenyang may pose a potential threat to human health and should be given attention.

Frontiers of parasitology research in the People's Republic of China: infection, diagnosis, protection and surveillance

Control and eventual elimination of human parasitic diseases in the People's Republic of China (P.R. China) requires novel approaches, particularly in the areas of diagnostics, mathematical modelling, monitoring, evaluation, surveillance and public health response. A comprehensive effort, involving the collaboration of 188 scientists (>85% from P.R. China) from 48 different institutions and universities (80% from P.R. China), covers this collection of 29 articles published in Parasites & Vectors. The research mainly stems from a research project entitled “Surveillance and diagnostic tools for major parasitic diseases in P.R. China” (grant no. 2008ZX10004-011) and highlights the frontiers of research in parasitology. The majority of articles in this thematic series deals with the most important parasitic diseases in P.R. China, emphasizing Schistosoma japonicum, Plasmodium vivax and Clonorchis sinensis plus some parasites of emerging importance such as Angiostrongylus cantonensis. Significant achievements have been made through the collaborative research programme in the following three fields: (i) development of strategies for the national control programme; (ii) updating the surveillance data of parasitic infections both in human and animals; and (iii) improvement of existing, and development of novel, diagnostic tools to detect parasitic infections. The progress is considerable and warrants broad validation efforts. Combined with the development of improved tools for diagnosis and surveillance, integrated and multi-pronged control strategies should now pave the way for elimination of parasitic diseases in P.R. China. Experiences and lessons learned can stimulate control and elimination efforts of parasitic diseases in other parts of the world.

First report of Toxoplasma gondii seroprevalence in peafowls in Yunnan Province, Southwestern China

Background

Toxoplasma gondii is an intracellular protozoan parasite infecting almost all warm-blooded animals, including birds, with a worldwide distribution. Surveys of T. gondii infection in wild birds have been reported extensively in the world, but little is known of T. gondii infection in peafowls worldwide. This study was performed to determine the seroprevalence of T. gondii infection in peafowls in Yunnan Province, southwestern China.

Methods

Sera from 277 peafowls, including 272 blue peafowls (Pavo cristatus) and 5 green peafowls (Pavo muticus) originated from two geographic areas in Yunnan Province were assayed for T. gondii antibodies using the modified agglutination test (MAT).

Results

Specific T. gondii antibodies were detected in 35 of 277 (12.64%) peafowls (MAT titer ≥ 1:5). Seropositive birds were found in both species, 33 in 272 blue peafowls and 2 in 5 green peafowls. There was no significant difference in T. gondii seroprevalence between the adolescent birds (6.74%) and the adult birds (6.67%) (P > 0.05). The geographical origins of peafowls was found to be highly associated with T. gondii infection in the present study, a statistically significant difference in T. gondii seropositivity was observed between peafowls from Kunming (31.08%) and those from Xishuangbanna Dai Autonomous Prefecture (5.91%) (OR = 10.956, 95% CI = 1.632-73.545, P = 0.014). Statistical analyses showed that there were no significant interactions between ages and geographical origins of peafowls (P > 0.05).

Conclusions

The results of the present survey indicated that infection of peafowls with T. gondii is widespread in Yunnan Province, which has significant public health concerns and implications for prevention and control of toxoplamosis in this province. To our knowledge, this is the first seroprevalence report of T. gondii infection in China’s southwestern Yunnan Province.

Canine and feline parasitic zoonoses in China

Canine and feline parasitic zoonoses have not been given high priority in China, although the role of companion animals as reservoirs for zoonotic parasitic diseases has been recognized worldwide. With an increasing number of dogs and cats under unregulated conditions in China, the canine and feline parasitic zoonoses are showing a trend towards being gradually uncontrolled. Currently, canine and feline parasitic zoonoses threaten human health, and cause death and serious diseases in China. This article comprehensively reviews the current status of major canine and feline parasitic zoonoses in mainland China, discusses the risks dogs and cats pose with regard to zoonotic transmission of canine and feline parasites, and proposes control strategies and measures.

Seroprevalence of Toxoplasma gondii infection in pet dogs in Shenyang, northeastern China

In recent years, surveys of Toxoplasma gondii infection in dogs have been reported throughout the world, including China. However, information is lacking regarding the prevalence of T. gondii infection in pet dogs in northeastern China. In the present study, we report the seroprevalence of T. gondii in pet dogs in Shenyang, northeastern China. Sera samples from 328 pet dogs in 5 districts were examined for T. gondii antibodies with an indirect hemagglutination antibody (IHA) test; 10.0% tested seropositive. There were no significant differences in terms of sex, age, and locality (P > 0.05). The results indicate that infection by T. gondii is widely prevalent in pet dogs in Shenyang, northeastern China, which has potential implications for public health in this area.

Seroprevalence of Toxoplasma gondii infection in pet dogs in Kunming, Southwest China

Background

Toxoplasmosis is a zoonotic parasitic disease caused by the protozoan Toxoplasma gondii, which infects almost all warm-blooded animals, including humans, with a worldwide distribution. However, little is known of T. gondii seroprevalence in pet dogs in Kunming, the capital of Yunnan Province, southwest China. The objective of this investigation was to estimate the seroprevalence of T. gondii infection in pet dogs in this area.

Methods

A total of 611 serum samples were collected from 7 pet hospitals in Kunming, and assayed for T. gondii antibodies by the indirect haemagglutination (IHA) using a commercially-marked kit.

Results

132 (21.6%) pet dogs were positive for T. gondii antibodies, and the seroprevalence ranged from 17.3% to 34.7% among different sampling regions, the difference was statistically significant (P < 0.05). The T. gondii seroprevalence in female and male dogs were 20.8% and 22.4%, respectively, the difference was not statistically significant (P > 0.05). The seroprevalence ranged from 17.5% to 23.6% among different age groups, but the difference was not statistically significant (P > 0.05), and there were no interactions in statistics (P > 0.05) between gender and age of pet dogs in the region.

Conclusions

The findings of the present survey indicate high T. gondii seroprevalance in pet dogs in Kunming, southwest China, posing significant public health concern. It is necessary to enhance integrated strategies and measures to prevent and control T. gondii infection in pet dogs in this area.

First report of Toxoplasma gondii infection in market-sold adult chickens, ducks and pigeons in northwest China

BACKGROUND

Toxoplasma gondii infection is a global concern, affecting a wide range of warm-blooded animals and humans worldwide, including poultry. Domestic and companion birds are considered to play an important role in the transmission of T. gondii to humans and other animals. However, little information on T. gondii infection in domestic birds in Lanzhou, northwest China was available. Therefore, this study was performed to determine the seroprevalence of T. gondii infection in domestic birds in Lanzhou, northwest China.

METHODS

In the present study, the seroprevalence of T. gondii antibodies in 413 (305 caged and 108 free-range) adult chickens, 334 (111 caged and 223 free-range) adult ducks and 312 adult pigeons in Lanzhou, northwest China, were examined using the modified agglutination test (MAT).

RESULTS

30 (7.26%) chickens, 38 (11.38%) ducks and 37 (11.86%) pigeons were found to be positive for T. gondii antibodies at the cut-off of 1:5. The prevalences in caged and free-range chickens were 6.23% and 10.19% respectively, however, statistical analysis showed that the difference was not significant (P > 0.05). The seroprevalences in caged and free-range ducks were 6.31% and 13.90% respectively, but the difference was not statistically significant (P > 0.05).

CONCLUSIONS

The results of the present survey indicated the presence of T. gondii infection in adult chickens, ducks and pigeons sold for meat in poultry markets in Lanzhou, northwest China, which poses a potential risk for T. gondii infection in humans and other animals in this region. This is the first seroprevalence study of T. gondii infection in domestic birds in this region.

First report of Toxoplasma gondii prevalence in Tibetan pigs in Tibet, China

Toxoplasma gondii infection is widely prevalent in humans and animals, including pigs throughout the world. In this study, the seroprevalence of T. gondii infection in Tibetan pigs in China was investigated for the first time. A total of 427 serum samples were collected from Tibetan pigs in Nyingchi prefecture, Tibet, between April and December 2010, and were assayed for antibodies to T. gondii using the modified agglutination test (MAT). Ninety-seven (22.72%) pigs were found to be positive with MAT titers of 1:25 or higher. Slaughter pigs had the highest seroprevalence, compared with seroprevalence in fattening pigs, growing pigs, or piglets, although the difference was not statistically significant (p≥0.05). The results of the present survey indicate that T. gondii is highly prevalent in Tibetan pigs in Tibet, which poses a significant public health concern in this unique region of the world.

Serological survey of Toxoplasma gondii in Tibetan mastiffs (Canis lupus familiaris) and yaks (Bos grunniens) in Qinghai, China

Background

Toxoplasma gondii is an amphixenosis which has extensive hosts. In recent years, the prevalence of T. gondii in China has been reported, while little is known on the survey of T. gondii infection in northwest China, especially in yaks (Bos grunniens) and Tibetan mastiffs (Canis lupus familiaris). The current study survey the infection of T. gondii in Tibetan mastiffs and yaks in Qinghai Province, China.

Methods

The indirect hemagglutination test (IHAT) was used to examine T. gondii antibodies in 1 795 serums, including 192 Tibetan mastiffs and 1603 yaks in Qinghai Province, China.

Results

In this study, the seroprevalence of T. gondii infection was 8.52%. Twenty (10.42%) of 192 serums of Tibetan mastiffs and 133 (8.30%) of 1603 serums of yaks were seropositive. The seroprevalence of T.gondii infection in Tibetan mastiffs in breeding farm (1.08%) was lower than that in the field (19.19%), and the difference was statistically significant (P <0.05). The seroprevalence of antibodies to T.gondii in yaks ranged from 5.45% to 13.28% among the four different areas. The seroprevalence in different age groups were determined with apparent association.

Conclusions

The results indicated that T.gondii infection was prevalent in Tibetan mastiffs and yaks, which have implications for public health in this region. To our knowledge, this is the first seroprevalence survey of Tibetan mastiffs infected by T. gondii in The People’s Republic of China.

Stray dogs as indicators of Toxoplasma gondii distributed in the environment: the first report across an urban-rural gradient in China

Background

Toxoplasmosis is an important parasitic zoonosis caused by the protozoan Toxoplasma gondii that is distributed world-wide and infects a variety of hosts. However, the prevalence of T. gondii in the environment (such as soil, water and food) is largely unknown. Due to the technical difficulty in oocyst counting directly, an alternative assay using the serologic status of T. gondii in free-living animals, such as stray or free-living dogs, as an indicator, can be used to evaluate environmental contamination indirectly, as they are exposed to the same risk of infection as humans and other animals.

Results

In the present study, 231 stray or free-living dogs across an urban-rural gradient were examined to assess the frequency of T. gondii in the environment. Specific antibodies to T. gondii were found in 93 dogs (40.3%) by enzyme-linked immunosorbent assay (ELISA), and no statistically significant differences were observed in seroprevalences of T. gondii between urban dogs (38.7%) and rural dogs (41%) (p > 0.05).

Conclusions

A high seroprevalence of T. gondii in stray or free-living dogs in the present study indicates that there would be a wide distribution and a constant infection pressure of T. gondii across an urban-rural gradient, and the oocysts of T. gondii in the environment would be an important source of infection for humans and other animals both in urban and rural areas in China.

Comparison of a Commercial ELISA with the Modified Agglutination Test for Detection of Toxoplasma gondii Antibodies in Sera of Naturally Infected Dogs and Cats

BACKGROUND

Toxoplasma gondii can infect all warm-blooded animals. Modified agglutination test (MAT) and ELISA are widely used for the detection of T. gondii antibodies. However, there is little information on their acceptability for detecting antibodies in companion animals.

METHODS

This study compared ELISA and MAT for their ability to detect T. gondii infection in naturally infected dogs and cats. Blood samples were collected from dogs and cats in different areas of Beijing, China and analyzed by ELISA and MAT. The χ(2) test and κ analysis were used to evaluate their efficiency and agreement.

RESULTS

For dogs, the seroprevalence of T. gondii antibodies detected by ELISA was 34.7%, which was significantly higher than that detected by MAT (P<0.05). There was no significant difference between ELISA and MAT for detecting T. gondii antibodies in cats. Good agreements between MAT and ELISA were seen in both dogs and cats; however, inconsistent results were demonstrated by κ analysis and in MAT titer assay.

CONCLUSION

Serum-based ELISA may be more satisfactory for screening test of T. gondii infection in dogs, whereas both methods could be acceptable in cats.

Seroprevalence of Toxoplasma gondii infection in household and stray cats in Lanzhou, northwest China

Background

Toxoplasma gondii is an important protozoan parasite infecting humans and almost all warm-blooded animals. As the only definitive host, cats play a crucial role in the transmission of T. gondii infection by shedding parasite oocysts in their feces. However, little information on T. gondii infection in cats was available in Lanzhou, northwest China. This study was performed to determine the seroprevalence of T. gondii infection in household and stray cats in Lanzhou, northwest China.

Results

A total of 221 (179 households and 42 strays) blood samples were collected from clinically healthy cats admitted to several pet hospitals located in Lanzhou City, between November 2010 and July 2011 for the serological detection of T. gondii infection. The majority (207) of these cats represented Chinese Lihua cats. 47 of 221 (21.3%) examined cats were seropositive for T. gondii infection using the modified agglutination test (MAT) at the cut-off of 1:25. The seroprevalence in household and stray cats was assessed to be 15.6% and 45.2%, respectively, and the difference was statistically significant (P <0.05). The seroprevalence ranged from 15.1% to 25.8% among different age groups, but the differences were not statistically significant (P >0.05). Studies showed that there was no relationship between seroprevalence and the gender (P >0.05).

Conclusions

The present survey indicated the high seroprevalence of T. gondii in cats in Lanzhou, northwest China, which poses a threat to animal and human health. Therefore, measures should be taken to control and prevent toxoplasmosis of cats in this area.

Toxoplasma gondii infection in pregnant women in China

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common parasitic infections in humans. Primary infection in pregnant women can be transmitted to the fetus leading to miscarriage or congenital toxoplasmosis. Carefully designed nationwide seroprevalence surveys and case-control studies of risk factors conducted primarily in Europe and America, have shaped our view of the global status of maternal and congenital infection, directing approaches to disease prevention. However, despite encompassing 1 in 5 of the world's population, information is limited on the status of toxoplasmosis in China, partly due to the linguistic inaccessibility of the Chinese literature to the global scientific community. By selection and analysis of studies and data, reported within the last 2 decades in China, this review summarizes and renders accessible a large body of Chinese and other literature and aims to estimate the seroprevalence in Chinese pregnant women. It also reviews the prevalence trends, risk factors, and clinical manifestations. The key findings are (1) the majority of studies show that the overall seroprevalence in Chinese pregnant women is less than 10%, considerably lower than a recently published global analysis; and (2) the few available appropriate studies on maternal acute infection suggested an incidence of 0·3% which is broadly comparable to studies from other countries.