Seroprevalence and risk factors for Toxocara infection in children from an urban large setting in Northeast Brazil

Epidemiological profile of human toxocariasis in patients examined at Evandro Chagas Institute (IEC/SVSA/MS) between 2014 and 2019

INTRODUCTION

Toxocariasis is caused by nematodes of Toxocara genus, which infest dogs and cats, with humans serving as paratenic hosts.

METHODS

The epidemiological profile of patients examined for toxocariasis between October 2014 and October 2019 at Evandro Chagas Institute (IEC) was outlined. The frequency of anti-T. canis IgG antibodies were evaluated using the Enzyme Linked Immunosorbent Assay (ELISA) method.

RESULTS

From a total of 734 samples, 56% were from male (p < 0.05). Regarding age, the group with the most solicitations were from ≤11 years old individuals (p < 0.05). Pará state had the highest number of exams requested (92%), with the majority from residents of urban areas, accounting for 81.5% of samples (p < 0.05). The overall toxocariasis seroprevalence was 41.8%, the male sex being the most frequent with 60.9% (p < 0.05). The most affected age group was ≤11 years old, with a total of 67.8% of positive samples (p < 0.05).

CONCLUSION

The high rates obtained emphasize the need for complementary studies on toxocariasis in Brazil, especially in Pará state, contributing to epidemiological surveillance actions in the control of this infection. Besides, health campaigns for domestic and stray animals, also can contribute to a more effective surveillance in controlling parasitic infections and encourages the One Health approach.

Toxocariasis: potential association with bronchial asthma, and pneumonia among pediatric children

Toxocariasis is an underestimated geohelminthic infection which shows respiratory changes concurrent with larval migration. The purpose of the present study was to detect Toxocara seropositivity in asthmatic and pneumonic children, and in turn to evaluate its association with the children clinical manifestations, laboratory test results, and sociodemographic risk factors. A total of 50 asthmatic, 50 pneumonic children and 50 healthy controls were subjected to stool analysis by direct wet mount and concentration techniques to exclude possible cross reactivity. Blood samples were collected for complete blood count and assessment of eosinophil count. Sera were examined for anti-Toxocara IgG antibodies, and measurement of total IgE level. Anti Toxocara IgG was detected in 27.3% (41/150) of the studied children. It was significantly higher in asthmatic group compared to controls (26%. p value = 0.033) and significantly highest in pneumonia group compared to both bronchial asthma group (46%. p value = 0.030) and control group (10%. p value = 0.001). There was a significant association between anti Toxocara IgG seroprevalence and each of eosinophilia, total IgE and both combined. Anti Toxocara IgG showed significant higher percentage in asthmatic children who recorded history of soil contact and pets contact as compared to control and pneumonic groups. Toxocara IgG seropositivity was highly associated with fever, cough, wheezes and dyspnea with statistical significance. Toxocara seropositivity has to be considered as a vital associated factor for asthmatic and pneumonic children, and eventually better to be considered in differential diagnosis by pediatricians. Further studies are still needed to explore the correlation between toxocariasis and different patient categories.

Immunomodulation in the intestinal mucosa of mice supplemented with Lactobacillus rhamnosus (ATCC 7469) and infected with Toxocara canis

Toxocariasis is an anthropozoonosis caused by the helminth Toxocara canis that shows different clinical manifestations as visceral, ocular, or neurological toxocariasis forms. Probiotics have been studied as alternatives to prevent and treat this parasitosis. Lactobacillus rhamnosus is a prospect that presents immunomodulatory activity that acts to strengthen the intestinal barrier. In this context, the main objective of this study was to evaluate the protective capacity and immunomodulatory action of the probiotic Lactobacillus rhamnosus at the level of the intestinal mucosa in different stages of T. canis infection (acute and chronic). Mice were supplemented by oral gavage with 1 × 10⁷ UFC/mL L. rhamnosus for 15 days before inoculation with 100 embryonated eggs of T. canis. Euthanasia of mice was conducted at three different time points: 2, 15 and 30 days post-inoculation (PI). The brain, lungs and liver were collected to evaluate the intensity of infection. The small intestines were removed, and mucosal cells of the duodenum were collected to perform gene analysis of IFN-γ, IL-10, IL-4 and IL-13 by real-time polymerase chain reaction (qPCR). Jejunum and ileum segments were analysed by histological techniques. A reduction of 51% in infection intensity was observed in the tissue of supplemented animals evaluated 2 days PI; however, analysis of groups 15 and 30 days PI did not show a protective effect. The intestinal mucosa of supplemented animals presented an inflammatory process that initiated at 2 days PI, persisted at 15 days PI and had regressed at 30 days PI. IL-13 transcription was increased in the probiotic group 2 days after supplementation ended; however, the same increase was not observed in the group that was supplemented and infected. Toxocara canis modulated the local immune system, with suppression of IFN-γ at 2 days PI and increased levels of IL-4 and IL-10 at 15 days PI. These results indicate that, under the studied conditions, the protective effect of Lactobacillus rhamnosus against infection caused by T. canis is not related to IL-4, IL-10 or IFN-γ but could be influenced by IL-13 action at 2 days PI. The probiotic stimulated immune cell recruitment to the intestinal mucosa, which can be involved in the diminished capacity of larval penetration in the mucosa, resulting in the reduced infection intensity observed during acute infection.

A survey on the seroprevalence of toxocariasis and related risk factors in Eosinophilic children of Northwest Iran

Background

Toxocariasis is a serious zoonotic helminthic disease caused by the nematodes; Toxocara species.

Aim

A cross-sectional study was conducted to determine the seroprevalence of toxocariasis and related risk factors in eosinophilic children referred to the pediatrics hospital of Qazvin province northwest Iran during 2019-2020.

Methods

A total of 200 blood samples were collected from eosinophilic children referred to the Qods Pediatrics Hospital. Demographic data, clinical symptoms, and dogs- and soil-contact history were collected. The presence of anti-Toxocara IgG antibody was evaluated by T. canis IgG ELISA kit.

Results

Anti-Toxocara IgG antibodies were detected in 14 (7%) of the total eosinophilic children. The seropositive rate of toxocariasis in hyper-eosinophilic children (>1000/mm3) was 15.1%, while the seropositivity was 4.1% in children with eosinophilia status (500-999/mm3). There was a significant association between the eosinophilia rate and seropositivity (P<0.05). Also, seroprevalence in asymptomatic eosinophilic children was 4.4%, while in children with clinical symptoms it was 17.1%. Accordingly, a statistically significant difference was found between clinical symptoms and Toxocara infection (P<0.05).

Conclusion

The prevalence of toxocariasis in eosinophilic children is a serious health problem in the study area. Therefore, serologic evaluation for the diagnosis of Toxocara infection is recommended for eosinophilic children.

T oxocara canis prevalence in soil, dog stool, and human serum samples from a rural village in Los Baños, Laguna, Philippines

Toxocariasis is a zoonotic disease caused by Toxocara spp. from dogs and cats. The Philippines is among the countries recorded to have abundant stray cats and dogs; however, few studies have been done to elucidate the transmission dynamics and the potential risks associated with toxocariasis. This study was conducted in a rural village in Los Baños, Laguna, Philippines to determine the prevalence of toxocariasis among selected public schoolchildren and identify some risk factors that can contribute to the transmission dynamics of toxocariasis in the study site. To elucidate this, serum samples from 50 public school children (ages 8-13) were tested using a Toxocara canis IgG ELISA kit, while 60 randomly selected households were chosen for collection of soil and dog samples. Sixty soil and dog fecal samples were collected and processed through modified sucrose flotation technique and formalin-ethyl acetate concentration technique, respectively. Knowledge, attitudes and practices (KAP) survey was conducted per household to determine potential risk factors. Results revealed that 60% of the public-school children examined were positive for anti-Toxocara canis antibodies, while 38.3% of the soil samples and 28% of the dog fecal samples were found positive for contamination with Toxocara ova. Deworming of pets was found to be significantly correlated to risk factors of infection (p < 0.05). This study highlights the potential risks of toxocariasis infection of residents in rural communities. Strict implementation of ordinances related to responsible pet ownership as well as promotion of sanitation and hygiene should be employed.

Toxocara canis extract fractions promote mainly the production of Th1 and regulatory cytokines by human leukocytes in vitro

Helminths possibly down-modulate immune responses to airborne allergens through the induction of a regulatory network. The identification of helminths bioactive molecules is highly desirable, given their immunomodulatory potential which could be used in immunotherapies for allergy and autoimmune diseases. To investigate the immunoregulatory potential of the adult Toxocara canis crude extract and ten protein fractions of its extract, human peripheral blood mononuclear cells (PBMC) from 10 allergic and 9 non-allergic individuals were cultivated, in vitro, in the presence or absence of these antigens, and their supernatants were evaluated for cytokine production (TGF-β, IL-10, IL-12, TNF-α, IL-6, IL-5, IL13, and IL-17). To determine the cell viability, the PBMC were cultivated for 24 h in the presence of the antigens and, following, they were subjected to a cytotoxicity assay. The viability of the PBMC was not affected by incubation with the T. canis antigens. As some fractions stimulated the production of immunoregulatory (TGF-β and/or IL-10), IL-12 and Th1 (TNF-α) cytokines, without stimulating Th2 cytokines (IL-5 and IL13) and IL-17, it was proposed that they would be potential candidates for further studies, especially involving the purification and characterization of specific proteins, which could be tested separately to evaluate their specific role as adjuvants in immunotherapy for inflammatory diseases.

Proteomics and immunoblotting analyses reveal antigens that optimize the immunodiagnosis of the infection by Toxocara spp

BACKGROUND

Toxocariasis is an infection caused by the round worms Toxocara canis and Toxocara cati. It occurs worldwide though it is more prevalent in developing countries. For the diagnosis of toxocariasis, the most used method is the indirect enzyme-linked immunosorbent assay (indirect ELISA), based on the detection of specific antibodies using the excreted/secreted products from T. canis larvae (TES) as antigens, but it cross-reacts with several helminth infections. For this reason, there is a need to investigate species-specific immunoreactive proteins, which can be used for the development of a more sensitive and specific diagnosis.

OBJECTIVE

To investigate immunoreactive protein candidates to be used for the development of a more sensitive and specific diagnosis of Toxocara spp. infection in humans.

METHODS

We have used immunoblotting and mass spectrometry to select four Toxocara canis immunoreactive proteins that were recombinantly expressed in bacteria and evaluated as potential new diagnostic antigens (rMUC3, rTES 26, rTES32 and rCTL4). The recognition of these recombinant proteins by total serum IgG and IgG4 was assayed using the purified proteins in an isolated manner or in combination.

RESULTS

The IgG ELISAs performed with individual recombinant antigens reached values of sensitivity and specificity that ranged from 91.7% to 97.3% and 94.0% to 97.9%, respectively. Among the analyses, the IgG4 immunoassay was proven to be more effective, revealing a sensitivity that ranged from 88.8% to 98.3% and a specificity of 97.8% to 97.9%. The IgG4 ELISA was shown to be more effective and presented no cross-reactivity when using combinations of the rTES 26 and rCTL4 recombinant proteins. The combination of these two molecules achieved 100% sensitivity and specificity.

CONCLUSIONS

The use of only two recombinant proteins can contribute to improve the current panorama of toxocariasis immunodiagnosis for, with a better optimization and reduced cost. This article is protected by copyright. All rights reserved.

Soil contamination by Ancylostoma spp. and Toxocara spp. eggs in elementary school playgrounds in the extreme south of Brazil

Millions of people worldwide, and especially schoolchildren, may be infected by geohelminths due to their exposure to a contaminated environment. The aim of this study was to evaluate soil contamination by Ancylostoma spp. and Toxocara spp. eggs in recreation areas at elementary schools in Pelotas, state of Rio Grande do Sul, Brazil. Sand samples were collected from 22 schools and were processed using the centrifugal flotation method. Helminth eggs with zoonotic potential were found in 12 out of the 22 schools (54.5%). Contamination by Ancylostoma spp. and Toxocara spp. was observed in 36.4% (8/22) and 27.3% (6/22) of the soil samples collected at these schools, respectively. These findings of eggs show that the school communities are exposed to risks of zoonotic transmission.

The global prevalence of Toxocara spp. in pediatrics: a systematic review and meta-analysis

BACKGROUND

Toxocariasis is a zoonotic parasitic disease caused by Toxocara canis and Toxocara cati in humans. Various types of T. canis are important.

PURPOSE

The current study aimed to investigate the prevalence of Toxocara spp. in pediatrics in the context of a systematic review and meta-analysis.

METHODS

The MEDLINE (PubMed), Web of Sciences, Embase, Google Scholar, Scopus, and Cumulative Index of Nursing and Allied Health databases were searched to identify peer-reviewed studies published between January 2000 and December 2019 that report the prevalence of Toxocara spp. in pediatrics. The evaluation of articles based on the inclusion and exclusion criteria was performed by 2 researchers individually.

RESULTS

The results of 31 relevant studies indicated that the prevalence of Toxocara spp. was 3%-79% in 10,676 cases. The pooled estimate of global prevalence of Toxocara spp. in pediatrics was 30 (95% confidence interval, 22%-37%; I2=99.11%; P=0.00). The prevalence was higher in Asian populations than in European, American, and African populations.

CONCLUSION

Health policymakers should be more attentive to future research and approaches to Toxocara spp. and other zoonotic diseases to improve culture and identify socioeconomically important factors.

Measurement of the IgG Avidity Index in the Diagnosis of Clinical Toxocariasis Patients

Toxocara spp. are parasitic nematodes responsible for human toxocariasis, a common zoonotic helminth infection. The five main features of human toxocariasis are the classical ocular toxocariasis and visceral larva migrans syndrome, followed by covert toxocariasis, common toxocariasis and neurotoxocariasis. The diagnosis of toxocariasis is feasible by considering clinical symptoms, anamnestic history and serology laboratory results; however, serological criteria cannot be used to distinguish active Toxocara infection from past exposure, which is an area of much discussion in clinical practice. In this context, we developed avidity tests (ELISA and immunoblotting) and evaluated their clinical usefulness in distinguishing past from active toxocariasis. Our study involved 46 patients divided into two groups: “active toxocariasis” (n = 14) and “chronic toxocariasis” (n = 32). According to the avidity indices obtained for both the chronic and active toxocariasis groups, we proposed two thresholds: first, an AI lower than 32% supports an active infection; secondly, a threshold above 42% can exclude an active infection. In order to use this assay in routine clinical practice, however, is still requires standardisation with regards to the method and threshold values, which can be established through studies involving larger populations.

Serosurvey of anti-Toxocara antibodies and risk factors in adolescent and adult pregnant women of southeastern Brazil

Toxocariasis is worldwide endemic parasitic anthropozoonosis with high risk to those in in vulnerable populations and particularly during pregnancy and childhood. Although the prevalence of anti-Toxocara spp. antibodies has been extensively studied, risk factors of pregnant women of different ages remains to be established. This study was designed to i) assess the presence of anti-Toxocara spp. antibodies in pregnant women that presented to the public health system in a city of southeastern Brazil, and ii) determine the risk factors for toxocariasis in adolescent and adult pregnant women. This cross-sectional study included 280 pregnant women (71 aged up to and including 17 years [adolescents] and 209 aged 18 years and older [adults]). Pregnant women voluntarily agreed to complete a socioeconomic questionnaire and provide serum samples. Anti-Toxocara IgG antibodies were screened by Enzyme-Linked Immunosorbent Assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis. Overall, 20.7% of pregnant women were seropositive (33.8% of adolescents and 16.3% of adults). Prevalence in pregnant adolescents was 2.6-fold higher than in adults (Odds ration [OR]: 2.63; 95% CI: 1.42-4.86, p = 0.003). Multivariate analysis revealed that contact with soil (p = 0.01; OR = 4.76) and being in the first trimester of pregnancy (p = 0.03; OR = 0.17) had significantly greater risk of toxocariasis for adolescents, and attainment of elementary through middle school education level (p = 0.05; OR = 8.33) was a risk factor in adult pregnant women. Toxocariasis is likely underreported and neglected in adolescent pregnant women; this age group should always be monitored for toxocariasis and correspondent clinical signs, particularly at late pregnancy.

Human Toxocariasis: 2010 to 2020 Contributions from Brazilian Researchers

This is a review of the published contributions made by Brazilian researchers between 2010 and 2020 on the natural history of human toxocariasis and the effects of human toxocariasis on nonhuman paratenic hosts.

A prospective seroepidemiological study of toxocariasis during early childhood in coastal Ecuador: potential for congenital transmission and risk factors for infection

Background

Although Toxocara spp. infection has a worldwide distribution, to our knowledge, no data from birth cohorts have been reported in published studies on the potential for congenital transmission and determinants of infection in early childhood.

Methods

We followed 290 mother-infant pairs from birth to 5 years of age through periodic collection of data and samples at birth, 7 and 13 months and 2, 3 and 5 years of age. Data on potential risk factors and confounders were collected by maternal questionnaire. Blood for plasma was collected from the mother at time of birth and periodically from the child for detection of anti-Toxocara spp. immunoglobulin G (IgG) antibodies using a Toxocara canis larval excretory-secretory antigen-based enzyme-linked immunosorbent assay. Stool samples were collected from the mother around the time of birth and periodically from the child for microscopic detection of soil-transmitted helminths (STH). Associations between potential risk factors and Toxocara spp. seroprevalence and seroconversion were estimated using multivariable logistic regression and generalized estimating equations.

Results

Toxocara spp. seroprevalence was 80.7% in mothers and in children was 0%, 9.3%, 48.4%, 64.9%, and 80.9% at 7 months, 13 months, 2, 3 and 5 years, respectively. Risk factors significantly associated with increases in seroprevalence over the first 5 years of life in multivariable analyses were age [Odds ratio (OR) 2.06, 95% confidence interval (CI) 1.39–2.27, P < 0001], male sex (female vs. male: OR 0.66, 95% CI 0.48–0.89, P = 0.006), maternal ethnicity (non-Afro vs. Afro-Ecuadorian: OR 0.65, 95% CI 0.47–0.91, P = 0.011), lower maternal educational and socioeconomic level, and childhood STH (OR 2.29, 95% CI 1.51–3.47, P < 0.001). Seroconversion rates for infection were greatest at 2 years of age (3.8%/month). Factors associated significantly with seroconversion at 2, 3 or 5 years were childhood STH infection, male sex, and more frequent domestic cat exposure.

Conclusions

Our data, from an area of high Toxocara spp. endemicity, indicate no congenital transmission but high rates of seroconversion after 13 months of age reaching maternal levels of seroprevalence by 5 years of age. Factors associated with seroprevalence and seroconversion included STH infections, domestic cats, maternal ethnicity, male sex, STH infections, and markers of greater poverty.

Seroprevalence of Toxocara canis infection and associated risk factors among primary schoolchildren in rural Southern Thailand

BACKGROUND

Human toxocariasis is a parasitic zoonosis caused by a parasite in the genus Toxocara and is transmitted mainly by the accidental ingestion of embryonated Toxocara canis (dog roundworm) or T. cati (cat roundworm) eggs. Several studies reported that children were the main population at risk for T. canis infection. Currently, no reports on the seroprevalence of T. canis infection in Thailand are available, and its status remains unknown among children who live in rural areas of southern Thailand.

OBJECTIVE

This study aimed to investigate the seroprevalence of T. canis infection and its associated risk factors among primary schoolchildren in rural areas of Nakhon Si Thammarat Province, Thailand.

METHODS

A total of 177 schoolchildren between 6 and 13 years of age were recruited between June and July 2019. Serum anti-T. canis IgG antibodies were detected with a commercial ELISA kit. A questionnaire administered by direct interviews was used to collect demographic and behavioral risk factor data.

RESULTS

The overall seroprevalence of T. canis infection was 58.2% (103 of 177). The univariate analysis revealed that schoolchildren who did not practice handwashing before a meal (crude odds ratio (COR) = 3.67, 95% CI 1.93-6.95, P < 0.001), did not practice hand washing after animal contact (COR = 2.89, 95% CI 1.53-5.47, P = 0.001), and drank untreated water (COR = 1.87, 95% CI 1.00-3.48, P = 0.049) had an increased risk of acquiring T. canis infection. However, after adjusting for confounders, only a lack of handwashing before a meal remained a significant risk factor (adjusted odds ratio (AOR) = 2.20, 95% CI 1.11-4.34, P = 0.023). Age, sex, owning a dog, and eating fresh vegetables were not significantly associated with T. canis infection in the current study.

CONCLUSIONS

This is the first serological investigation of T. canis infection among schoolchildren in Thailand. The high rate of Toxocara seropositivity reflected high levels of exposure to T. canis among schoolchildren in rural areas of southern Thailand. The results also provide baseline data regarding modifiable risk behaviors for effective T. canis infection prevention strategies in southern Thailand, especially strengthening hand washing practices among schoolchildren.

High seroprevalence of Toxocara antibodies in pregnant women attending an antenatal clinic at a university hospital in Ile-Ife, Nigeria

BACKGROUND

Human toxocariasis is a neglected zoonotic disease and its impact on human health is underestimated. Studies investigating the occurrence of toxocariasis in pregnancy are very scarce in Nigeria. This study investigated the seroprevalence of Toxocara spp. antibodies as well as the possible risk factors in pregnant women who routinely attended an antenatal clinic in a university hospital in Ile-Ife, Osun state.

METHODS

Blood samples were collected from 413 participating pregnant women between October 2017 and February 2018. Epidemiological data were obtained through a structured questionnaire. The sera were screened for anti-Toxocara IgG antibodies by western blot technique based on Toxocara canis larval excretory-secretory antigens, targeting low molecular weight bands of 24-35 kDa, specifically for T. canis infection.

RESULTS

The overall seroprevalence was 92.49% (382/413). There was no significant difference in the seroprevalence rate of Toxocara spp. infection between pregnant women aged ≤30 y and those aged >30 y (91.63 vs 93.33%; OR 1.28, 95% CI 0.61 to 2.67, p=0.511). The seroprevalence rate increased with the number of miscarriages but there was no statistical significance (p>0.05). Moreover, no significant associations were found between Toxocara spp. seropositivity and other studied risk factors (p>0.05).

CONCLUSION

The high seroprevalence of Toxocara spp. in pregnant Nigerian women needs comprehensive health education regarding personal hygiene and how to avoid exposure to this parasite infection.

Seroepidemiology, modifiable risk factors and clinical symptoms of Toxocara spp. infection in northern Iran

Toxocariasis is one of the most important and widespread neglected tropical infectious diseases. We designed a cross-sectional study to assess the seroepidemiological aspects of toxocariasis among the general population in northern Iran. A total of 630 rural subjects were enrolled to participate in the study. The presence of anti-Toxocara immunoglobulin G (IgG) was tested using a commercially available enzyme-linked immunosorbent assay. A structured questionnaire was also used to evaluate the potential risk factors and related clinical signs/symptoms. The presence of anti-Toxocara IgG antibodies was detected in 148 of the 630 rural subjects (23.5% [95% confidence interval {CI} 21.8 to 25.1]). By multivariate analysis, age (odds ratio [OR] 2.89 [95% CI 1 to -8.3], p=0.04), eating improperly washed vegetables (OR 4.05 [95% CI 2.47 to 6.64], p<0.001), contact with dogs (OR 3.31 [95% CI 2.13 to 5.12], p<0.001) and exposure to soil (OR 3.56 [95% CI 2.13 to 5.13], p<0.001) were significantly associated with the seroprevalence of Toxocara. The clinical study also demonstrated that the seroprevalence of Toxocara infection was significantly associated with asthma (OR 3.78 [95% CI 1.63 to 8.75], p<0.001) and ophthalmic disorder (OR 1.83 [95% CI 1.04 to 3.21], p=0.034). The findings proved that residents of rural communities in tropical regions may be heavily exposed to Toxocara spp. We highly recommend more investigations in high-risk groups.

Serodiagnostic methods for diagnosing larval toxocariasis

Toxocariasis is a human infection primarily caused by larvae of Toxocara canis from dogs, and also by T. cati from cats. Children have a more significant risk of acquiring the infection due to their closer contact with pets, and greater chances of ingesting soil. Diagnosis of toxocariasis is based on clinical, epidemiological, and serological data. Indirect IgG ELISA is a widely used serodiagnostic method for toxocariasis, with native T. canis TES most commonly used as the antigen. Western blots, using the same antigen, can be used to confirm positive ELISA findings to reduce false-positive results. Improvements in Toxocara serodiagnosis include the use of recombinant TES antigens, simpler and more rapid assay formats, and IgG4 subclass detection. Also, incorporation of recombinant T. cati TES protein increases the diagnostic sensitivity. Development of antigen detection tests using polyclonal and monoclonal antibodies, nanobodies, or aptamers can complement the antibody detection assays, and enhance the effectiveness of the serodiagnosis.

Helminth eggs with zoonotic potential in the vicinity of public schools in southern Brazil

The aim of this study was to evaluate environmental contamination by helminth eggs with zoonotic potential that were found in dog feces in the vicinity of elementary schools. Seventy-nine samples of dog feces were collected from 28 municipal schools located in five neighborhoods in Pelotas, Rio Grande do Sul (RS), Brazil. The samples were processed using the Willis-Mollay technique and analyzed using an optical microscope (40X), to identify any parasite eggs present. All neighborhoods were positive and 74.7% of the samples exhibited one or more helminth genera. The agent with the highest prevalence was Ancylostoma spp. (93.2%), followed by Trichuris spp. (18.6%), Toxocara spp. (11.9%) and Toxascaris (1.7%). These data show that there is a need for greater care towards controlling these helminths with zoonotic potential, including responsible pet ownership and daily activities to clean and collect dog feces in the vicinity of schools, because these are places where children play and study.

Análise epistemológica dos conhecimentos científicos sobre Toxocara sp. com ênfase na infecção humana

Resumo Este artigo objetivou analisar a evolução do conhecimento sobre Toxocara sp. em seu aspecto zoonótico por meio de dados científicos entre os anos de 1996 a 2015 utilizando a epistemologia como ferramenta. A análise epistemológica da evolução do conhecimento sobre o aspecto zoonótico de Toxocara sp. no Brasil demonstrou que, de uma maneira geral, foram agregadas poucas novas informações as quais tiveram, ao longo do período estudado, absorção lenta, descontínua, e não foram inseridas na realidade social do ponto de vista de Saúde Pública.

Seroepidemiology of Toxocara canis in Children under 14 Years Referring to Laboratories of Sistan and Baluchestan Province in Southeast of Iran

BACKGROUND

The aim of the present survey was to assess thr seroepidemiologic and parasitological aspects of Toxocara canis infection in children under 14 yr old.

METHODS

Overall, 963 sera were collected from children in the Sistan and Baluchistan Province, Southeast of Iran during the period from Sep 2015 to Jun 2016. IgG antibody against T. canis in the subjects' sera was evaluated using the commercial ELISA kit.

RESULTS

Anti-Toxocara IgG were detected in the serum of 17 (1.7%) of the participants. In the examined children, the highest presence of anti-Toxocara antibodies was 2.1% (9/418) in 6-10-yr olds, which was higher than other age groups (P<0.05). Anti-Toxocara antibodies were significantly higher in males (2.4% or 12/492) than in females (1.1% or 5/471) (P<0.03). Highest serological prevalence of T. canis occurred in tribes (5.5% or 4/69), followed by rural areas (0.9% or 7/757), while in the urban area it was 0.1% (6/163) (P<0.01). A significant association was seen between the serological prevalence of T. canis and laboratory findings such as eosinophilia (P=0.001) and red blood cell count (P=0.02).

CONCLUSION

Seroprevalence of Toxocara infection is high among children living in the poor regions of southeast Iran.

Seroprevalence of Toxocara in Children from Urban and Rural Areas of Ilam Province, West Iran

Objectives

The present study was performed to determine the seroprevalence of Toxocara in children ≤ 10 years old, from rural and urban areas of Ilam.

Methods

Serum samples from 383 children ≤ 10 years old, were selected randomly from rural and urban areas of Ilam province and surveyed using enzyme-linked immunosorbent assays.

Results

The total rate of infection with Toxocara was 22% (31% with a history of contact with dogs and cats, and 14% without a history of contact). Of those infected, 23% were male and 18% were female, 36% lived a rural life and 20% had an urban life. A significant correlation was found between the incidence of disease, and urban and rural life, as well as exposure to dogs and cats. There was no correlation between prevalence and gender or age.

Conclusion

Given the high prevalence of infection with Toxocara amongst children in Ilam province, preventive work in the community such as education in risk management and periodic treatment with anti-parasitic drugs and elimination of stray dogs and cats is an appropriate measure.

Lactobacillus rhamnosus reduces parasite load on Toxocara canis experimental infection in mice, but has no effect on the parasite in vitro

Human toxocariasis is a neglected global parasitic zoonosis. The efficacy of drug treatment for this disease has been hindered by the biological complexity of the main etiological agent, the nematode Toxocara canis. Experimental studies have shown the potential of probiotics to promote a reduction in the parasite load of T. canis larvae. This study aimed to evaluate the effect of probiotic Lactobacillus rhamnosus ATCC 7469 on the parasite load of BALB/c mice with acute toxocariasis and evaluate the direct effect of this probiotic on T. canis larvae in vitro. In vivo administration of probiotics reduced the parasite load of T. canis larvae by 53.3% (p = 0.0018) during the early stage of infection in mice. However, when analyzed in vitro, it was observed that the probiotic did not present a deleterious effect on the larvae, as approximately 90% of these remained viable. These results demonstrate the potential of the probiotic L. rhamnosus in the reduction of T. canis larvae in BALB/c mice and suggest it could be used as an alternative means for the controlling of visceral toxocariasis. However, further studies are required to elucidate the mechanisms of action promoted by this probiotic.

Risk factors for Toxocara spp. seroprevalence and its association with atopy and asthma phenotypes in school-age children in a small town and semi-rural areas of Northeast Brazil

Toxocara canis, Toxocara cati, are roundworms that live in the intestines of dogs and cats, respectively, and are predominantly agents of human toxocariasis. Studies have suggested that Toxocara spp. seroprevalence increases levels of total and aeroallergen-specific IgE (sIgE), asthma prevalence and asthma morbidity. Nevertheless, other work reported a negative association between Toxocara spp. seropositivity with skin hypersensititity and a positive association with sIgE. The objective of the present study was to evaluate risk factors for acquiring Toxocara spp. infection and to investigate possible significant association between its seroprevalence with atopy and asthma. Students from elementary schools, residents in a small town and its surroundings of Northeast Brazil, underwent blood sampling to measure levels of anti-Toxocara spp. IgG, peripheral blood eosinophils, and specific IgE to aeroallergens. We used univariable and multivariable logistic regression analyses to assess possible risk factors for Toxocara spp. seropositivity and its association with atopy, wheeze/asthma with asthma phenotypes, in a sample of 791 elementary school children aged 6-13 years. Toxocara spp. seroprevalence reached 63.6%; 49.9% had sIgE; 7.2% and 3.3% had atopic wheeze/asthma and non-atopic wheeze/asthma respectively. Risk factors associated with Toxocara spp. seropositivity were: contact with dogs (adj. OR 2.33; 95% CI=1.70-3.19) and cats (adj. OR 3.09; 95% CI=2.10-4.55), and male sex (adj. OR 2.21; 95% CI=1.62-3.02). The presence of anti-Toxocara IgG was statistically associated with blood eosinophils >4% and >10% (adj. OR 1.84; 95% CI=1.33-2.55 and adj. OR 2.07; 95% CI=1.45-2.97, respectively), and atopy (adj. OR 2.00; 95% CI=1.49-2.68), but it was not associated with wheeze/asthma. Concluding, the results obtained in this study showing the association of Toxocara spp. seroprevalence with sIgE may suggest a possible immunological cross-reactivity between IgE epitopes from Toxocara spp. and aeroallergens.

Clinical usefulness of Western blotting and ELISA avidity for the diagnosis of human toxocariasis

The serodiagnosis of human toxocariasis is difficult. Specific IgGs detected routinely with ELISA based on Toxocara excretory-secretory (TES) antigens often persist for years at an elevated level, which does not allow either the differentiation between an active and persistent infection or monitoring of the effect of treatment. Additionally, false-positive results may occur in co-infections with other helminths due to cross-reactions. We evaluated the usefulness of an IgG avidity index (AI) and a Western blotting (WB) IgG in the diagnosis of patients suspected of Toxocara infection. We studied 138 subjects who were submitted to serological testing two or more times. Confirmation of an infection by WB was achieved in 73.2% of patients. A high AI was obtained in 89.1% of patients, and low AI and borderline AI were found in only 10.9%. Low and borderline values of AI remained at similar levels in subsequent studies over 2-3 years. The results showed the necessity of obligatory verification of all ELISA IgG positive and questionable results by WB. The index of IgG avidity may be helpful in excluding recent infection, but its usefulness in detecting an active phase of invasion requires further research.

Seroepidemiological study and associated risk factors of Toxocara canis infection among preschool children in Osun State, Nigeria

Human toxocariasis is caused by the nematode, Toxocara canis and it is a poorly understood phenomenon in Nigeria. Seroepidemiological studies have not been previously carried out among the preschool aged children in Nigeria. A cross-sectional study was conducted in pre-school children in four communities from Osun State, Nigeria between January and July 2016. A total of 308 children Aged 9 months and 5 years were studied comprising 53.2% (164/308) male and 46.8% (144/308) female. Blood samples were collected and screened for the presence of anti-Toxocara IgG antibodies by Western blot analysis based on the excretory-secretory antigens of larva T. canis (TcES), targeting low molecular weight bands of 24 - 35kDa specific for T. canis. Questionnaires were given to parents/guardians of the studied children to collect information regarding relationship between infection and host factors. The overall seroprevalence of Toxocara infection was 37.3%. The seroprevalence in the studied preschool children ranged from 18.2% in children less than one year old to a max of 57.6% in children aged 3 years and above. The logistic regression analysis of risk factors showed that children's age (odds ratio (OR)=6.12, 95% confidence interval (CI)=1.25-29.90, p=0.02), contact with dogs (OR=3.17, 95% CI=1.40-7.20, p=0.01) and parent's religion (OR=0.54, 95% CI=0.32-0.91, p=0.02) were the risk factors associated with Toxocara infection. However, after adjustment by multivariate logistic regression analysis, contact with dogs (p=0.02) remained the only statistically significant risk factor. Preschool children were exposed early in life to T. canis infection as 18.18% of children less than one year old were infected. This is the first serological investigation of T. canis infection among preschool children in Nigeria. The results show high levels of exposure to T. canis infection among the studied group and contact with the dog plays the predominant risk factor. It indicates high transmission with the consequent of visceral or ocular larva migrans and neurologic disorder in these children. The results also provide baseline data for effective prevention strategies of toxocariasis in Southwest Nigeria and the study recommends prompt interventional measures, particularly health education on personal hygiene.

Identification of Toxocara spp. eggs in dog hair and associated risk factors

AIM

The aim of the study was to identify the presence of eggs of Toxocaraspp. in dog hair and to identify any risk factors associated with this.

MATERIALS AND METHODS

A total of 96 dogs were sampled collecting hair from the head, perianal and hindquarters. Epidemiologic data from each animal were recorded to identify risk factors. The samples of hair were washed with solutions of distilled water, phosphate-buffered saline and Tween 20 detergent. Microscopic analysis was subsequently performed for the identification of eggs.

RESULTS

Out of the total dogs, 41.7% were positive for the presence of parasite egg in their hair. Toxocara eggs were found in hair from the head (14.5%), tail (20.8%), and limbs (10.4%). Dogs, younger than 12 months old, showed higher values (4.7%) of egg presence in the perianal area (p<0.05). The principal risk factors for the presence of eggs in hair were not deworming (odds ratio [OR]=3.60, p<0.004) and not brushing (OR=2.26, p<0.12).

CONCLUSION

These results show that in the state of Mexico there is a high percentage of dogs contaminated with Toxocara spp. eggs in their hair. This should be seriously considered due to the potential problems of toxocariasis and the risk to public health.

Frequency of Toxocara spp. antibodies in umbilical cords of newborns attended atthe University Hospital in Southern Brazil and factors associated with infection

Toxocariasis is a neglected and geographically widespread parasitic disease. The detection of specific antibodies associated with this disease is required to confirm its clinical diagnosis and to aid in prevention. Although helminth infection during pregnancy can promote foetal immune responses with long-term effects, specific information regarding the risk of Toxocara spp. infection to the human foetus during pregnancy is lacking. Therefore, the present study aimed to investigate the frequency of antibodies against Toxocara spp. in umbilical cord serum samples to determine the neonatal risk factors associated with Toxocara spp. infection. A cross-sectional study of the frequency of specific antibodies against Toxocara spp. was performed on umbilical cord samples of 280 neonates. A cord blood sample was obtained from each newborn after parturition, and serum samples were examined by enzyme-linked immunoassay. Epidemiological data were obtained through a questionnaire regarding obstetric history (abortion history, premature birthhistory, and pregnancy and birth numbers), general aspects (animal contact anddiet) and socio-economic factors. The frequency of anti-Toxocara spp. IgG antibodies in the umbilical cords of neonates was 20% in serum pre-adsorbed with Ascaris spp. antigen. Family income and dog ownership were considered risk factors associated with infection. No association was found between reproductive disorders and Toxocara seropositivity. The 20% frequency rate of anti-Toxocara spp. IgG antibodies in sera from umbilical cords of newborns can be related to IgG binding at the maternal-foetal interface, requiring greater care during pregnancy. Anti-Toxocara IgM and IgE antibodies no were found in umbilical cord serum samples, indicating that no vertical transmission of these parasites occurred in this population. Studies regarding antibodies against Toxocara spp. in umbilical cord sera are important for determining neonatal exposure to these parasites.

Effect of polymorphisms on TGFB1 on allergic asthma and helminth infection in an African admixed population

BACKGROUND

Allergic asthma is a complex disorder that results from a combination of genetic and environmental factors. Studies suggest that helminth infections can activate a regulatory network characterized by the production of regulatory cytokines, such as interleukin 10 and transforming growth factor β1 (TGF-β1) and subsequently protect against immune-mediated diseases, such as asthma. On the other hand, TGF-β1 is increased in the lungs of individuals with asthma and may modulate airway inflammation. The role of TGF- β 1 single-nucleotide polymorphisms (SNPs) in allergic disease remains inconclusive.

OBJECTIVE

To evaluate the effects of genetic variations in the TGF-β1 on allergy and helminths infections in children.

METHODS

We tested for association among 4 TGF-β1 SNPs and allergic asthma, specific IgE, skin prick test result, and IL-10 production in 1,335 Brazilians. In addition, we analyzed the association with markers of helminth infection (parasite burden, anti-Ascaris IgE, and worm specific IgG4). The polymorphisms were genotyped using Taq Man probes.

RESULTS

We found an association between rs1800470 (C allele) and atopic wheezing (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.37-0.95) and markers of allergy (OR, 0.41; 95% CI, 0.22-0.79). In contrast, a positive association was observed between the haplotype ACCA and Trichuris trichiura infection (OR, 1.85; P = .003) and Ascaris lumbricoides infection (OR, 2.01; P < .001). This haplotype was also associated with increased IL-10 production (β = 50.7; P < .001).

CONCLUSION

Individuals with TGF-β1 polymorphisms have an increased susceptibility to helminth infections and a lower risk of developing allergy. These studies suggest that immune modulation of allergic disease results not only from environmental factors but also from genetic susceptibility and IL-10 production.

Epidemiological Study of Toxocar canis in Children under 14-Years-Old and Dogs in Zabol and Chabahar Districts, Southeast of Iran

BACKGROUND

The purpose of this study was seroepidemiological and parasitological assessment of Toxocara canis infection in children and dogs in Zabol and Chabahar, Iran.

METHODS

This study was a descriptive-analytic study with a simple random sampling of children under 14 yr old, referring to urban, rural, and tribal laboratories of Zabol and Chabahar, Sistan and Baluchestan Province, Iran in 2016. Demographic data, clinical, and laboratory conditions of patients were collected through interviews, questionnaires, and blood count measuring. The prevalence of IgG antibodies against T. canis was assessed by ELISA. T. canis eggs in dogs (as the original host) were also assessed by examining animal feces. Then the data were analyzed using SPSS 19 software and descriptive statistics, chi-square and ANOVA statistical tests.

RESULTS

Totally, 364 patients were enrolled, of which 51.6% were female and mean±SD age of participants was 7.2 (±3.7) yr. IgG antibodies against T. canis was observed in 3.8% of cases. A significant association was found between the seroprevalence of T. canis and eosinophil (P=0.003) and red blood cell count (P=0.04). We also found a significant association between serological prevalence of T. canis and demographic parameters, such as city of residence (P=0.003), gender (P=0.04), consumption of vegetables (P=0.01), and the living place (P=0.04). Mean antibody titration was 2.2 ±1.1, with statistically significant difference among age groups (P=0.001). In addition, T. canis infection was positive in 27.5% of dogs living in the study areas.

CONCLUSION

High risk of infection represented in patients referring to laboratories of Zabol and Chabahar. In addition, given the fact that dogs are the final hosts to transfer Toxocara infection to humans, this study emphasizes the need to control the population of stray dogs in the region to prevent the development of disease in the human society.

Seroprevalence and associated risk factors of Toxocara infection in Korean, Manchu, Mongol, and Han ethnic groups in northern China

Toxocariasis is a very prevalent zoonotic disease worldwide. Recently, investigators have focused more on Toxocara spp. seroprevalence in humans. Information regarding Toxocara seroprevalence in people from different ethnic backgrounds in China is limited. For this study, blood samples were collected from a total of 802 Han, 520 Korean, 303 Manchu, and 217 Mongol subjects from Jilin and Shandong provinces. The overall Toxocara seroprevalence was 16·07% (14·21% Han, 20·58% Korean, 11·22% Manchu, 18·89% Mongol). Living in suburban or rural areas, having dogs at home, exposure to soil, and consumption of raw/undercooked meat were risk factors for Toxocara infection. Exposure to soil was identified as the major risk factor for Toxocara seropositivity in all of the tested ethnicities. To the best of our knowledge, this is the first report concerning Toxocara infection in Manchus and Mongols in China. The present study provided baseline data for effective prevention strategies of toxocariasis in northeast China and recommends improvements in personal hygiene standards to achieve this goal.

A Systematic Review of Toxocariasis: A Neglected But High-Prevalence Disease in Brazil

Toxocariasis is an anthropozoonosis that occurs in all parts of the world. In particular, this disease can often be found in developing countries and in regions, where basic sanitation conditions are poor. However, industrialized countries have reported seroprevalence rates as high as 14.2% in humans. The definitive hosts of the disease are dogs and cats, whereas humans are a paratenic host. To determine the burden of toxocariasis in Brazil, we followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to conduct a systematic review of the literature. Using keywords and applying the established criteria, we identified 160 publications and selected 22 articles for further analysis. The seroprevalence of toxocariasis in various regions of the country ranged from 4.2% to 65.4%. The highest prevalence was found in the northeast region, although the majority of the studies identified were from the southeast region. The findings suggest the importance of raising awareness among health professionals and public authorities about the fact that toxocariasis is a health problem.

Seroprevalence and risk factors of Toxocara infection among children in Shandong and Jilin provinces, China

This cross-sectional study was aimed to investigate the Toxocara serology in children in Shandong and Jilin provinces, China using an enzyme-linked immunosorbent assay (ELISA). The overall Toxocara seroprevalence among the study population (n=1458) was 19.3%, sick children (26.4%) had significantly higher seroprevalence than clinically healthy children (14.4%) (P<0.05), and the highest Toxocara seroprevalence was found in children suffering from chronic cough (40.6%), followed by recurrent abdominal pain (40.0%), recurrent headache (38.1%), slight fever (36.2%), and recurrent vomiting (31.6%). Place of residence, education level, type of school, keeping dogs at home, contact with dogs and cats and exposure with soil were found to be associated with Toxocara infection. Our findings show that children infection with Toxocara is common in Shandong and Jilin provinces, eastern and northeastern China, indicating an immediate need for implementing strategies and measures to prevent and control Toxocara infection in children in China.

The Seropositivity of Toxocara spp. Antibodies in Pregnant Women Attented at the University Hospital in Southern Brazil and the Factors Associated with Infection

BACKGROUND

Human toxocariasis is a parasitic zoonosis with a worldwide distribution but is underdiagnosed with an underestimated impact on human health. The ingestion of embryonated eggs of Toxocara spp. present on the hands or in contaminated food or water is the main mode of infection. The only record of Toxocara congenital infection in humans occurred in a premature infant. Helminth infections during pregnancy may be associated with reproductive disorders. Studies investigating the occurrence of toxocariasis in pregnancy are scarce, as is research on the possible implications of these parasites in reproductive health. The aim of this study was to determine the seroprevalence of antibodies to Toxocara spp. in pregnant women and to identify risk factors associated with its infection.

METHODOLOGY/PRINCIPAL FINDINGS

The cross-sectional study of the seropositivity of specific antibodies for Toxocara spp. was performed on 280 pregnant women. Serum samples were examined with enzyme-linked immunoassay. Epidemiological data were obtained through a questionnaire containing information about obstetric history, general life style choices, and the social and economic status of the women. The prevalence of Toxocara spp. IgG in pregnant women was 6.4%. Some of the risk factors associated with the infection were owning dogs (p = 0.003), living in the city centre (p = 0.028), living at the city beach (p = 0.003), and having a family income at or below minimum wage (p < 0.001). There was no association between reproductive disorders and Toxocara seropositivity.

CONCLUSIONS/SIGNIFICANCE

The seroprevalence of 6.4% for Toxocara spp. in pregnant women shows that there was exposure to the parasite. The study demonstrates the need for attention for the completion of clinical diagnosis parameters, as well as the expansion of highly specific serological studies in different regions to understand the impact of toxocariasis in pregnancy.

Seroprevalence, disease awareness, and risk factors for Toxocara canis infection among primary schoolchildren in Makoko, an urban slum community in Nigeria

In this study, we investigated the seroprevalence of Toxocara canis infection in southern Nigeria, which previously was unknown, in addition to evaluating disease awareness and potential risk factors for schoolchildren in an urban slum community. In total, 366 primary schoolchildren were investigated for the presence of anti-Toxocara IgG antibodies. Blood was collected and screened by a Western blot analysis based on the excretory-secretory antigens of larval T. canis (TcES), targeting low molecular weight bands of 24-35kDa specific for T. canis. Children were considered seropositive if their serum reacted with TcES when diluted to a titer of 1:32. Questionnaires concerning possible risk factors were given to the schoolchildren to acquire data on this infection. The overall seroprevalence of Toxocara infection was 86.1% (315/366). The logistic regression analysis of risk factors showed that children's age (odds ratio (OR)=2.88, 95% confidence interval (CI)=1.08-7.66, p=0.03), contact with dogs (OR=0.51, 95% CI=0.28-0.94, p=0.03), the age of the dog (OR=0.34, 95% CI=0.18-0.68, p=0.002), the feeding location of the dog (OR=0.31, 95% CI=0.12-0.79, p=0.01), the consumption of raw vegetables (OR=0.89, 95% CI=0.54-1.48, p=0.004), and the drinking of unboiled water (OR=0.48, 95% CI=0.26-0.90, p=0.02) were risk factors associated with Toxocara infection. Although there was a high awareness of dogs being hosts of some parasites in this study, not much was known about T. canis. This is the first serological investigation of T. canis infection among primary schoolchildren in southern Nigeria. The high seroprevalence recorded is an indication of high transmission with the consequent risk of visceral or ocular larval migrans and neurologic toxocariasis in these children. Our findings suggest the need for prompt interventional measures, particularly health education on personal hygiene.

Seroepidemiology of Toxocariasis and Its Clinical Implications in Gwangju and Jeonnam-province, Korea

We investigated the seroepidemiological, clinical, and laboratory characteristics of patients suspected to have toxocariasis in Gwangju and Jeonnam-province, Korea. In total, 228 specimens were analyzed for anti-Toxocara canis IgG at two university hospitals from 2010 to 2012. The overall seropositive rate was 67.1%, and the seropositive rates among the eosinophilic and non-eosinophilic groups were 76.1% (105/138) and 53.3% (48/90), respectively. Risk factors for eosinophilia and toxocariasis were male sex (odds ratios [OR]=2.632 and 3.477, respectively) and a history of ingesting raw meat (OR=2.884 and 3.274, respectively), especially raw cow liver (OR=2.089 and 10.038, respectively). T. canis seropositivity (OR=5.807, P=0.004) and a history of consuming raw cow liver (OR=2.766, P=0.052) were risk factors for organ involvement. The anti-T. canis IgG level showed weakly positive correlations with eosinophil counts (r=0.234, P<0.001) and the duration of eosinophilia (r=0.155, P=0.019). Although limited to the regions of Gwangju and Jeonnam-province, this study supports the opinion that toxocariasis is a reasonable focus as a cause of eosinophilia and that it is also associated with organ involvement.

Toxocara seroprevalence among clinically healthy individuals, pregnant women and psychiatric patients and associated risk factors in Shandong Province, Eastern China

BACKGROUND

Toxocarosis is a widespread zoonosis caused by the ascarid nematodes Toxocara canis and Toxocara cati, which primarily infect dogs and cats, respectively. Most human infections with Toxocara are asymptomatic; however, some infected individuals may develop a serious illness and even death. Nevertheless, epidemiological knowledge regarding the prevalence and risks associated with Toxocara infection is limited in China. Therefore, we performed a cross-sectional pilot study and estimated the seroprevalence of Toxocara infection in humans in Shandong Province, eastern China for the first time, from June 2011 to July 2013, involving clinically healthy individuals, pregnant women and psychiatric patients, aiming to attract public attention to Toxocara infection.

METHODOLOGY/PRINCIPLE FINDINGS

Seroprevalence of Toxocara was determined using an enzyme-linked immunosorbent assay based on a cross-sectional study conducted in Qingdao and Weihai, Shandong Province, eastern China. Factors potentially associated with Toxocara infection were identified by logistic regression analysis. The overall Toxocara seroprevalence among the study population (n = 2866) was 12.25%, and a significantly higher seroprevalence in psychiatric patients (16.40%, 73/445) than that in clinically healthy individuals (13.07%, 187/1431) and pregnant women (9.19%, 91/990) was revealed. Univariate analyses suggested that keeping dogs at home (OR = 0.06, 95% CI 0.05-0.08, P<0.001), contact with cats and dogs (OR = 0.42, 95% CI 0.33-0.53, P<0.001) and exposure with soil (OR = 0.37, 95% CI 0.28-0.49, P<0.001) were risk factors associated with Toxocara infection.

CONCLUSIONS/SIGNIFICANCE

The present study revealed, for the first time, that human infection with Toxocara is common in eastern China, posing a significant public health concern. Increasing human and dog populations, population movements and climate change all will serve to increase the importance of this zoonosis. Further studies under controlled conditions are necessary to define potential morbidity associated with Toxocara infection.

Epidemiology and control of child toxocariasis in the western Brazilian Amazon - a population-based study

Toxocara spp. infection and the seroconversion rate in the Amazon have been poorly investigated. This study analyzed individual and household-level risk factors for the presence of IgG antibodies to Toxocara spp. in urban Amazonian children over a period of 7 years and evaluated the seroconversion rates over a 1-year follow-up. In children < 59 months of age, the overall prevalence rate was 28.08% in 2003 and 23.35% in 2010. The 2010-2011 seroconversion rates were 13.90% for children 6-59 months of age and 12.30% for children 84-143 months of age. Multilevel logistic regression analysis identified child age, previous wheezing, and current infection with hookworm as significant associated factors for Toxocara spp. seropositivity in 2003. In 2010, age, previous helminthiasis, and having a dog were associated with seropositivity, whereas having piped water inside the household was a protective factor. Control programs mainly need to target at-risk children, water quality control, and animal deworming strategies.