Seroepidemiology of Toxoplasma gondii infection in general population in a northern Mexican city

There is a lack of information about the seroepidemiology of T. gondii infection in the general population of Durango City, Mexico. Anti- Toxoplasma gondii IgG and IgM antibodies were sought in 974 inhabitants in Durango City, Mexico with the use of enzyme-linked immunoassays. in total, 59 (6.1%) of 974 participants (mean age 37 ± 16.1 yr) had IgG anti- T. gondii antibodies. Twenty (2.1%) of them also had IgM anti- T. gondii antibodies. IgG levels of 13-99, 100-150, and >150 International Units (IU)/ml were found in 14 (23.7%), 3 (5.1%), and 42 (71.2%) anti- T. gondii IgG-positive participants, respectively. Prevalence of infection increased with age (P < 0.05), and was significantly lower in participants born in Durango State than those born in other Mexican states (P < 0.01). Toxoplasma gondii infection was significantly associated with consumption of boar meat (adjusted odds ratio [OR] = 3.02; 95% confidence interval [CI]: 1.49-6.13), and squirrel meat (adjusted OR = 2.18; 95% CI: 1.17-4.09). in addition, infection was negatively associated with travel abroad (adjusted OR = 0.42; 95% CI: 0.23-0.77), and salami consumption (adjusted OR = 0.57; 95% CI: 0.32-0.99). This is the first report of seroprevalence and contributing factors for T. gondii infection in general population in Durango City, and of an association of the consumption of boar meat with T. gondii infection. This study provides a basis for the design of successful preventive measures against T. gondii infection.     

Seroepidemiology of Toxoplasma gondii infection in pregnant women in rural Durango, Mexico

The epidemiology of Toxoplasma gondii infection in pregnant women in rural Mexico is largely unknown. The seroepidemiology of T. gondii infection in 439 pregnant women from 9 communities in rural Durango State, Mexico was investigated. Using commercial enzyme-linked immunoassays, sera were tested for T. gondii IgG, IgM, and avidity antibodies. Prevalences of T. gondii IgG antibodies in the communities varied from 0% to 20%. Overall, 36 (8.2%) of the 439 women had IgG T. gondii antibodies. Ten (2.3%) women had also T. gondii IgM antibodies; IgG avidity was high in all IgM-positive women, suggesting chronic infection. None of the women, however, had delivered a known T. gondii-infected child. The seroprevalence was significantly higher (P < 0.05) in women from low socio-economic conditions (14%) than in those with higher socio-economic status (6.6%). Multivariate analysis showed that T. gondii infection was associated with soil floors at home (adjusted OR = 2.89; 95% CI: 1.12-7.49). This is the first epidemiological study of T. gondii infection in pregnant women in rural Mexico.     

Seroepidemiology of infection with Toxoplasma gondii in workers occupationally exposed to water, sewage, and soil in Durango, Mexico

Water, sewage, and soil are potential sources of infection for Toxoplasma gondii. Therefore, we sought to determine the prevalence of T. gondii infection and associated characteristics in 61 plumbers, 203 construction workers, and 168 gardeners in Durango City, Mexico. Participants were tested for T. gondii IgG and IgM antibodies with the use of enzyme-linked immunoassays. In addition, sociodemographic, clinical, and behavioral characteristics from each participant were obtained. IgG T. gondii antibodies were found in 4 (6.6%) plumbers, 17 (8.4%) construction workers, and 10 (6.0%) gardeners; T. gondii IgM antibodies were found in 3 (1.5%) construction workers and 4 (2.4%) gardeners, but in none of the plumbers. In the total population, the prevalence of T. gondii infection was significantly higher in workers living in suburban areas, without education, workers that consumed chorizo, and those who suffered from any disease (P < 0.05). In gardeners, prevalence of infection was significantly higher in those with blood transfusion, and memory impairment (P < 0.05). Multivariate analysis showed that T. gondii infection was positively associated with consumption of unwashed fruits (adjusted odds ratio [OR] = 2.41; 95% confidence interval [CI]: 1.13-5.13), and with raising animals (adjusted OR = 2.53; 95% CI: 1.00-6.37). This is the first report of contributing factors for T. gondii infection in workers occupationally exposed to water, sewage, and soil in a Mexican city, and results will contribute to the design of optimal preventive measures.     

Toxoplasma gondii infection and schizophrenia: a case control study in a low Toxoplasma seroprevalence Mexican population

There are conflicting reports concerning the association of Toxoplasma gondii infection and schizophrenia in humans. Therefore, we determined such association in a Mexican population of Mestizo ethnicity. Through a case-control study design, 50 schizophrenic patients and 150 control subjects matched by gender, age, residence place, and ethnicity were examined with enzyme-linked immunoassays for the presence and levels of T. gondii IgG antibodies and for the presence of T. gondii IgM antibodies. Schizophrenic patients attended a public psychiatric hospital in Durango City, Mexico, and the control group consisted of individuals of the general population of the same city. Socio-demographic, clinical and behavioral characteristics from the study subjects were also obtained. Both the seroprevalence and the level of T.gondii IgG antibodies were higher in schizophrenic patients (10/50; 20%) than in control subjects (8/150; 5.3%) (OR=4.44; 95% CI: 1.49-13.37; P=0.003). The IgG T. gondii levels higher than 150 IU/ml were more frequently observed in patients than in controls (10% versus 2%, respectively; P=0.02). One (50%) of the two patients with recently diagnosed schizophrenia and none of the controls had T. gondii IgM antibodies (P=0.01). T. gondii seropositivity was significantly higher in patients with a history of cleaning cat excrement (P=0.005), and suffering from simple schizophrenia (ICD-10 classification: F20.6) (P=0.03) than patients without these characteristics. Toxoplasma seroprevalence was also significantly higher in patients with simple schizophrenia (F20.6) than in those with paranoid schizophrenia (F20.0) (P=0.02). This study provides elements to clarify the controversial information on the association of T. gondii infection and schizophrenia.     

Oocyst ingestion as an important transmission route of Toxoplasma gondii in Brazilian urban children

Toxoplasmosis is a cosmopolitan protozoan infection. Data regarding risk factors for the post-natal acquisition of Toxoplasma gondii infection in childhood are limited. We conducted a serological survey for T. gondii IgG antibodies and associated risk factors in 1,217 children 4-11-yr-old from Salvador, Brazil, using a commercial ELISA kit; antibodies were found in 17.5% of the children. Age (OR = 2.18; 95% CI: 1.50-3.17) and maternal schooling level (OR = 0.62; 95% CI: 0.42-0.92) were negatively associated with infection. A greater number of siblings (OR = 1.53; 95% CI: 1.12-2.09), cat at home (OR = 1.54; 95% CI: 1.06-2.24), house with non-treated piped water (OR = 2.54; 95% CI: 1.22-5.31), and the absence of a flush toilet at home (OR = 1.45; 95% CI: 1.04-2.01) were positively associated with T. gondii infection. Our data suggest that low socioeconomic levels and poor hygiene habits are important factors in favoring T. gondii infection.     

Performance of a Western immunoblot assay to detect specific anti-Toxoplasma gondii IgG antibodies in human saliva

Toxoplasma gondii represents the most prominent infectious parasitic organism found in humans. While normally asymptomatic in healthy individuals, toxoplasmosis can cause abortion in patients during pregnancy, or can be fatal in immunosupressed individuals such as persons suffering from acquired immunodeficiency syndrom (AIDS). Toxoplasma gondii infection in humans is routinely assesssed by serological means. Here, we show that detection of anti-T. gondii IgG is also possible using a non-invasive methodology employing saliva. Sera and saliva of 201 healthy volunteers were investigated for the presence of anti-T. gondii-IgG antibodies by immunoblotting. The sera of 59 (29.4%) individuals showed IgG antibodies against T. gondii by ELISA, Vidas, and immunoblotting; 58 (98.3%) of these were also positive for anti-T. gondii IgG in the saliva immunoblot, with diagnostic relevant bands of Mr of 32-35 kDa and 40-45 kDa. The saliva immunoblot test exhibits a specificity of 100% and a sensitivity of 98.5%. Thus, saliva could be used as an alternative, non-invasive means for the detection of specific anti-T. gondii IgG in humans.     

Association of the presence of residual anti-Toxoplasma gondii IgM in pregnant women and their respective family groups in Miracema, Northwest Rio de Janeiro, Brazil

The seroprevalence of toxoplasmosis in 832 pregnant women in Miracema, Rio de Janeiro, was determined and 75.1% (625) and 2.0% (17) were anti-Toxoplasma gondii IgG and IgM positive, respectively. Out of the 17 IgM positive pregnant women, only one had low avidity IgG corresponding to the acute phase of the infection. All the other women presented with high avidity IgG and also presented with residual IgM anti-T. gondii. Of this sample, 106 received home visits (this includes 11 family nuclei of pregnant women with residual IgM anti-T. gondii, 68 nuclei of only IgG positive pregnant women and 27 nuclei of pregnant women with no antibodies to anti-T. gondii), resulting in 267 individuals visited. Out of these 267 individuals, 21 were positive for IgG and IgM anti-T. gondii and were candidates for the IgG avidity test. All of them presented with high avidity IgG and residual IgM. Five of these IgM+ individuals were (5/238; 2.1%) relatives of IgM negative pregnant women. The other 16 (16/29; 55.2%) were relatives of IgM+ pregnant women who were positive for residual IgM anti-T. gondii. This association was statistically significant (p = 0.0000). The analysis presented herein raises questions regarding the presence of residual IgM anti-T. gondii such as genetic determinants or even constant antigenic stimuli for the same family cluster.     

Role of Toxoplasma gondii HSP70 and Toxoplasma gondii HSP30/bag1 in antibody formation and prophylactic immunity in mice experimentally infected with Toxoplasma gondii.

Production of antibodies against Toxoplasma gondii (T. gondii)-derived stress proteins, T. gondii HSP70 (T.g.HSP70) and T.g.HSP30/bagl, in C57BL/6 and BALB/c mice perorally infected with cysts of the avirulent Fukaya strain of T. gondii was analyzed. Production of anti-T.g.HSP70 IgG antibodies was transient, whereas production of anti-T.g.HSP30/bag1 IgG antibodies persisted after infection in both C57BL/6 and BALB/c mice. C57BL/6 mice, a susceptible strain, predominantly produced IgG antibodies specific for T.g.HSP70, whereas BALB/c mice, a resistant strain, predominantly produced IgG antibodies specific for T.g.HSP30/bag1, after T. gondii infection. Immunization with rT.g.HSP30/bag1 enhanced, whereas immunization with rT.g.HSP70 reduced host protective immunity against T. gondii infection with a cyst-forming avirulent strain, Fukaya, and a virulent strain, RH.     

Seroepidemiology of Toxoplasma gondii Infection among Healthy Blood Donors in Taiwan

Toxoplasma gondii is an opportunistic, zoonotic pathogen with a worldwide distribution. There are large variations in the seroprevalence of T. gondii infection in different regions of the world. Although toxoplasmosis became a notifiable communicable disease in Taiwan in 2007, little is known about its epidemiology among the general population. This cross-sectional study aimed to survey the seroprevalence of T. gondii infection and its risk factors among healthy blood donors in Taiwan. Through collaborating with the Taiwan Blood Services Foundation, a total of 1,783 healthy blood donors from all six-branch blood service centers participated in this study. The blood samples were tested for the presence of T. gondii antibodies and DNA using enzyme immunoassays and real-time PCR, respectively. Structured questionnaires were used to gather information on risk factors for T. gondii infection. Of the 1,783 participants, 166 (9.3%) tested positive for anti-Toxoplasma IgG, while 5 (0.28%) tested positive for anti-Toxoplasma IgM. The five IgM positive donors had high avidity antibodies suggestive of past infection. No active parasitemia was detected by real-time PCR assays. Multivariate logistic regression showed that undercooked pork meat consumption (adjusted odds ratio [OR] = 2.9; 95% confidence interval [CI]: 1.3–6.5), raw mussels consumption (adjusted OR = 5.3; 95% CI: 1.5–19.1), having a cat in the household (adjusted OR = 2.0; 95% CI: 1.2–3.2), a lower education level (adjusted OR = 1.6; 95% CI: 1.1–2.3), and donation place in eastern Taiwan (adjusted OR = 2.5; 95% CI: 1.6–3.9) were independent risk factors for Toxoplasma seropositivity. These findings provide information on the seroprevalence and epidemiology of T. gondii infection among healthy blood donors in Taiwan.     

Prevalence of Toxoplasma gondii infection in wild birds in Durango, Mexico

There is a lack of information concerning the prevalence of Toxoplasma gondii infection in wild birds in Mexico. In the present study, serum samples and tissues from 653 birds from Durango State, Mexico, were evaluated for T. gondii infection. Antibodies to T. gondii (modified agglutination test, titer 1∶25 or higher) were found in 17 (2.6%) of the 653 birds, including 1 of 2 curve-billed thrashers (Toxostoma curvirostre), 2 (1 Anas platyrhynchos, 1 Anas diazi) of 4 ducks, 1 of 2 eagles (Aquila sp.), 5 (27.8%) of 18 great-tailed grackles (Quiscalus mexicanus), 7 (1.3%) of 521 rock pigeons (Columba livia), and 1 (14.3%) of 7 quail (Coturnix coturnix). The seroprevalence of T. gondii infection in birds captured in a park outside the city zoo (11.6%, 8/69) was significantly higher than that found in birds from other regions (1.5%, 9/584, OR = 8.38; 95% CI: 2.82-24.77; P = 0.0001). Brains and hearts of 23 birds (17 seropositive, 6 seronegative) were bioassayed in mice for the isolation of T. gondii . Viable T. gondii was isolated from 1 of 7 seropositive pigeons. The DNA obtained from the T. gondii isolate from the pigeon was genotyped using the PCR-RFLP typing using 11 markers (B1, SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) and revealed an atypical genotype. This is the first report of T. gondii infection in great-tailed grackles, the Mexican duck, and curved-billed thrashers and the first survey of wild birds in Mexico.     

Seroprevalence of Toxoplasma gondii antibodies in cats from Durango City, Mexico

The prevalence of antibodies to Toxoplasma gondii was determined in sera from 105 domestic cats from Durango City, Mexico. Using a modified agglutination test, antibodies to this parasite were found in 21% of the 105 cats, with titers of 1:25 in 3 cats, 1:50 in 4 cats, 1:200 in 5 cats, 1:400 in 2 cats, 1:800 in 2 cats, 1:1,600 in 4 cats, and 1:3,200 or higher in 2 cats. Cats older than 1 yr had a significantly higher frequency of infection than that found in cats younger than 0.5 yr (41 vs. 13.2%, respectively; odds ratio = 4.55; 95% CI = 1.24-17.18; P = 0.01). Overall, the seroprevalence of T. gondii antibodies in cats in Durango, Mexico, is much lower compared with those reported in other countries.     

National seroprevalence of Toxoplasma gondii in India

This article reports the first national serological prevalence of Toxoplasma gondii in India. In total, 23,094 serum samples were tested for T. gondii IgG and IgM antibodies with the use of a solid-phase immunocapture ELISA. Antibodies (IgG) were found in 24.3%; IgM antibodies were detected in 2% of the samples. The lowest seroprevalences were in the northern parts of India, with the highest in the south. These data probably reflect the effects of significantly drier conditions and, therefore, a negative impact on the survivability of T. gondii oocysts.     

Seroprevalence of acquired toxoplasmosis in HIV-infected and apparently healthy individuals in Jos, Nigeria

Toxoplasma gondii IgG antibody seroprevalence was studied in two different populations of 219 HIV-infected patients and 144 apparently healthy individuals (AHIs). Clinical toxoplasmosis was assessed among the HIV-infected patients. Antibodies to T. gondii were detected in 85 (38.8%, 95% CI: 32.36%-45.26%) of the HIV-infected patients and in 30 (20.8%, 95% CI: 14.20%-27.46%) of the AHIs. Among the AIHs, males represented 22.0% of infections compared to females (20.0%) and individuals within age group 21-30 years accounted for the highest prevalence of 33.3% (95% CI: 11.56%-55.10%). There was no significant difference in the trend (Chi-square, P < or = 0.05). Assessment of epidemiological factors showed higher seroprevalence of Toxoplasma antibodies among those who eat rodents (29.6%) and those who constantly have contact with the soil (21.2%). Among the HIV-infected, individuals 31-40-years-old had the highest T. gondii seroprevalence (36.5%). Evaluation of the clinical findings of patients with concomitant toxoplasmosis and HIV infection greatly implicated fever (63.5%), headache (44.7%), rashes (41.2%) and anorexia (34.1%). This study contributes to the development of guidelines for the prevention and management of toxoplasmosis in HIV-infected patients and in apparently healthy individuals in a resource scarce setting.     

Seroepidemiology of Toxoplasma gondii infection among Chinese aboriginal and Han people residing in mountainous areas of northern Thailand

A seroepidemiological survey of Toxoplasma gondii infection among Chinese refugees, including Akka and Yau aborigines and Han people living in mountainous areas at elevations of 1,100-1,400 m in Chiang-Rai Province of northern Thailand, was conducted during January 2003 using the latex agglutination test. The overall seroprevalence of T. gondii infection was 9.1% for Akka aborigines, 37.9% for Yau aborigines, and 7.9% for Han people, respectively. No significant gender difference in seroprevalence was found among any of the groups (P > 0.05). The results of a multiple logistic regression analysis for Yau aborigines and Han people showed that the older the age, the higher the odds ratios (OR) of being seropositive (OR = 3.0, 95% confidence interval [CI] = 0.5 to 16.9, P < 0.001 and OR = 1.5, 95% CI = 0.3 to 8.0, P = 0.06 for the elderly group vs. the child group for the Yau aborigines and Han people, respectively). In contrast, the OR was lower among older Akka aboriginal populations (OR = 0.1, 95% CI = 0.0 to 0.4, P < 0.001). Ethnically, Yau aboriginal populations had a significantly higher seroprevalence than did the Akka aborigines and Han people (P < 0.001).     

Prevalence of Toxoplasma gondii antibodies and the relation to risk factors in cats of Colima, Mexico

The prevalence of Toxoplasma gondii antibodies in 80 domestic cats was studied in the city of Colima, Mexico, using an indirect IgG-ELISA. Antibodies were found in 28.8% of the cats, with significantly higher (P = 0.029) prevalence in southern and central zones (33.8%) than the northern zone (6.6%). Prevalence among cats fed with homemade food was higher than those eating commercial pellets (40.6% [vs.] 20.8%; P = 0.055). Overall, the prevalence of T. gondii antibodies in the cats of Colima was lower than in many other countries.     

Lacrimal secretory IgA in active posterior uveitis induced by Toxoplasma gondii

It is quite difficult to diagnose active toxoplasmosis in patients with ocular toxoplasmosis. Active posterior uveitis presumably due to Toxoplasma gondii infection (APUPT) is seldom produced during a prime-infection; hence most patients do not show high IgM antibodies. High levels of IgA have been described in active toxoplasmosis. The purpose of this study was to investigate possible association between APUPT and the specific anti-parasite sIgA in tears. The study was carried out as case-control. Tears of 25 clinically confirmed APUPT patients and 50 healthy control subjects were analyzed. All were IgG seropositive. Specific sIgA was determined by ELISA assay using T. gondii RH strain crude extract. Anti-T. gondii sIgA was found in 84% of the cases and in 22% of the control subjects. The intensity of the reaction was higher in APUPT cases (P = 0.007). There was strong association between APUPT patients and lacrimal sIgA (odds-ratio 18.61, P = 0.0001). ELISA test sensitivity was 84% and specificity 78%. Our data suggest that anti-T.gondii secretory IgA found in tears may become an important marker for active ocular toxoplasmosis.     

The prevalence of Toxoplasma gondii antibodies in wild and captive cetaceans from Japan

The seroprevalence of Toxoplasma gondii was investigated in wild and captive cetaceans from Japan. Antibodies against T. gondii were examined by both latex agglutination test (LAT) and indirect hemagglutination test (IHAT) for 77 serum or plasma samples obtained from 59 individuals of 6 species, including 2 hybrids. Antibody titers greater than 1:64 in LAT and greater than 1:640 in IHAT, indicative of the presence of T. gondii, were found in 11.9% of 59 individuals. In 7 samples that showed a positive reaction by IHAT, T. gondii titers were examined for each immunoglobulin (Ig) fraction separated by sucrose gradient centrifugation. The antibody peaks in each fraction were divided into 3 types, thought to be a reaction of IgM (type 1), IgG (type 2), and IgM with IgG (type 3). Type 1 was found in serum from a bottle-nosed dolphin (Tursiops truncatus) and a killer whale (Orcinus orca) sampled soon after capture off the Japanese coast in 1988; it was concluded that infection in the wild had occurred less than 15 yr before the study was performed. The prevalence of putative IgM and IgG antibodies from a captive-bred T. truncatus suggested that T. gondii infection also occurred in the aquarium.     

IGM and IGG response to 29-35-kDa Toxoplasma gondii protein fractions in experimentally infected goats

The evolution of the humoral responses of IgG and IgM against 29-35-kDa Toxoplasma gondii fractions from experimentally infected goats were studied and compared by ELISA with the use of whole T. gondii soluble extracts and 29-35-kDa electroeluted proteins as antigens. The IgM response to electroeluted proteins was detected from wk 1 to wk 3 postinfection, showing a similar evolution to that observed when T. gondii crude extracts were used as antigens. These results suggest that this group of proteins could be used for a more specific detection of anti-T. gondii IgM. In the same way, the IgG response was equivalent in both cases, although when 29-35-kDa T. gondii fractions were used as antigens, the level of specific IgGs reached a peak 2 wk before than when T. gondii crude extract was used. The detection by ELISA of anti-T. gondii IgM in goats does not seem to be affected by the presence of specific IgG in serum samples when 29-35-kDa protein fractions were used as antigens.     

Age-related Toxoplasma gondii seroprevalence in Dutch wild boar inconsistent with lifelong persistence of antibodies

Toxoplasma gondii is an important zoonotic pathogen that is best known as a cause of abortion or abnormalities in the newborn after primary infection during pregnancy. Our aim was to determine the prevalence of T. gondii in wild boar to investigate the possible role of their meat in human infection and to get an indication of the environmental contamination with T. gondii. The presence of anti-T. gondii antibodies was determined by in-house ELISA in 509 wild boar shot in 2002/2003 and 464 wild boar shot in 2007. Most of the boar originated from the "Roerstreek" (n = 673) or the "Veluwe" (n = 241). A binormal mixture model was fitted to the log-transformed optical density values for wild boar up to 20 months old to estimate the optimal cut-off value (-0.685) and accompanying sensitivity (90.6%) and specificity (93.6%). The overall seroprevalence was estimated at 24.4% (95% CI: 21.1-27.7%). The prevalence did not show variation between sampling years or regions, indicating a stable and homogeneous infection pressure from the environment. The relation between age and seroprevalence was studied in two stages. Firstly, seroprevalence by age group was determined by fitting the binary mixture model to 200 animals per age category. The prevalence showed a steep increase until approximately 10 months of age but stabilized at approximately 35% thereafter. Secondly, we fitted the age-dependent seroprevalence data to several SIR-type models, with seropositives as infected (I) and seronegatives as either susceptible (S) or resistant (R). A model with a recovery rate (SIS) was superior to a model without a recovery rate (SI). This finding is not consistent with the traditional view of lifelong persistence of T. gondii infections. The high seroprevalence suggests that eating undercooked wild boar meat may pose a risk of infection with T. gondii.     

Amplification of the secretory IgA response to Toxoplasma gondii using cholera toxin

Our study demonstrates that cholera toxin (CT) markedly enhances the intestinal anti-T. gondii antibody response following oral immunisation of mice with a T. gondii sonicate (TSo) and CT. The antibodies induced were mostly IgA and secretory IgA but a small quantity of IgG was also produced. In contrast, no intestinal anti-T. gondii IgM antibodies were detected. Anti-CT IgA antibodies were also present in intestinal secretions but in much lower quantities than the T. gondii-specific IgA. No anti-CT IgG nor IgM antibodies were detected. Western blot analysis showed that CT induced not only an increase of the intensity of the intestinal IgA antibody response to the 30-kDa band but also induced intestinal IgA antibodies against other major T. gondii proteins (p22, and the 28-kDa antigen) as recognised by specific monoclonal antibodies. The amplification of the anti-T. gondii secretory IgA response by means of an appropriate adjuvant may be one major step leading towards an orally induced immune protection against toxoplasmosis.