Anti-Toxocara spp. antibodies in an adult healthy population: serosurvey and risk factors in Southeast Brazil

Risk factors for toxocariasis during incarceration: the One Health intervention approach

Despite potential exposure to soil-transmitted helminths, especially when stray dogs and cats are present, toxocariasis in inmate populations remains to be established. Accordingly, the present study assessed the seroprevalence and associated risk factors of toxocariasis at the Women's State Penitentiary of Parana, Brazil. A total of 234/370 (63.2%; 95% CI 58.2-68.0) women inmates and 28/87 (32.2%; 95% CI 23.3-42.6) correctional officers were seropositive for anti-Toxocara spp. IgG by ELISA, with inmates 2.62-fold more likely positive (p = 0.00000026). The univariate model has identified that non-white (OR = 1.58, p = 0.047) and older than 39 years (OR = 1.28, p = 0.032) inmates were associated with mild but significant odds for seropositivity. Elementary or higher educational level was considered a protective factor for seropositivity. The presence of Toxocara spp. eggs was observed in 10/15 (66.7%) collected soil samples by centrifuge-flotation in Zinc Sulfate, and molecular analysis by PCR identified only Toxocara cati in these eggs. An intervention program was established with regular trap-neuter-release, with gradual removal for adoption (donation campaigns), treatment, and euthanasia when necessary (particularly due to advanced sporotrichosis). In addition, an educational awareness agenda was proposed, aiming to reduce soil contamination and accidental intake by the incarcerated population. A total of 40 feral cats were trapped, 20 males and 20 females, mostly adults. After trapping, 36 cats were neutered, treated, and microchipped in the Veterinary Teaching Hospital (VTH) at the Federal University of Paraná. Five trapped feral cats were euthanized, four diagnosed with advanced sporotrichosis, and one already neutered cat (not herein) with complications due to feline immunodeficiency virus (FIV). Female inmates presented higher seroprevalence for Toxocara spp. antibodies when compared to correctional officers, significantly associated with age, self-declared ethnicity (non-white), and lack of formal education. Despite the non-natural scenario of a state penitentiary, the One Health approach of Toxocara spp. has highlighted the interdisciplinary nature of the study and its relevance in understanding the complex interactions between human, animal, and environmental factors, particularly impacting female inmates. Further studies should establish the rate of inmate infection over time while deprived of liberty.

Seroprevalence of human toxocariasis in Latin America and the Caribbean: a systematic review and meta-analysis

Introduction

The current study aimed to quantitatively synthesize available evidence regarding the seroprevalence of human toxocariasis in Latin America and the Caribbean.

Methods

A systematic research involving six electronic databases was conducted using a research strategy that combined MeSH terms with free terms. Article selection and information extraction were performed using a double and independent approach. The Newcastle-Ottawa tool was used to assess the risk of bias in the included articles. The meta-analysis used the random-effects approach, with subgroup analysis and sensitivity analysis for risk of bias also being performed.

Results

We included 101 articles with a total of 31,123 participants. The studies were conducted between 1990 and 2022, with Brazil accounting for the largest number of studies (n = 37). The overall seroprevalence of human toxocariasis was 31.0% (95% CI: 27.0-35.0%, I2 = 99%). The prevalence of the main characteristics observed in seropositive patients were as follows: ocular toxocariasis (30.0%), asymptomatic (26.0%), and presence of dogs at home (68.0%). In addition, the seroprevalence was lower in studies including only adults than in those including children or both. In contrast, no differences in seroprevalences were found between studies conducted in the community and hospital.

Conclusion

The overall seroprevalence of human toxocariasis in Latin America and the Caribbean was high. Notably, our findings showed that the seroprevalence was increased among populations who kept a dog at home but was decreased in populations comprising only adults. Our findings can be used to establish epidemiological surveillance strategies for the prevention and early identification of toxocariasis.

Serosurvey of anti-Toxocara canis antibodies in people experiencing homelessness and shelter workers from São Paulo, Brazil

BACKGROUND

Despite being one of the most prevalent helminth parasitic zoonoses worldwide and particularly in socioeconomically vulnerable populations, toxocariasis remains to be fully investigated in persons experiencing homelessness. Accordingly, the present study has aimed to assess the seroprevalence and associated risk factors of Toxocara spp. exposure in persons experiencing homelessness and shelter workers from a day-shelter in São Paulo city, Brazil.

METHODS

Anti-Toxocara IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis.

RESULTS

Overall, anti-Toxocara IgG antibodies were detected in 89/194 (45.9%, 95% CI: 39.0-52.9%) persons experiencing homelessness, twice as high (OR = 2.2; 95% CI = 1.245-3.873; P = 0.0089) than the frequency of 22/79 (27.8%, 95% CI: 19.2-38.6) in shelter workers. College education was the only protective factor for Toxocara spp. exposure (OR: 0.23; P = 0.018) revealed by logistic regression.

CONCLUSIONS

Although indicating a multifactorial origin of toxocariasis, the present study has assessed a highly vulnerable population with high disease risks and premature death. Thus, the living conditions of the homeless population have influenced the high prevalence of anti-Toxocara antibodies verified here compared with domiciled shelter workers. Despite being less exposed, shelter and other outdoor workers may present an occupational risk to toxocariasis. Future studies should establish whether such environmental exposure might occur in persons experiencing homelessness in other regions worldwide.

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.

One Health approach on human seroprevalence of anti-Toxocara antibodies, Toxocara spp. eggs in dogs and sand samples between seashore mainland and island areas of southern Brazil

Toxocariasis, caused by Toxocara spp. nematodes, is among the top 5 neglected parasitic diseases worldwide; however, no comprehensive study to date has serologically compared infections in people and their dogs and environmentally contaminated soil or sand of mainland and island locations. Accordingly, this study aimed to assess the seroprevalence of anti-Toxocara antibodies in traditional human seashore populations, the presence of eggs in dogs' feces and hair, and the presence of eggs in environmental samples from islands compared to the adjacent mainland of southern Brazil. Overall, 212/328 (64.6%) people were positive for Toxocara spp. antibodies, including 125/190 (65.8%) island and 87/138 (63.0%) mainland residents. For dog samples, 12/115 (10.43%) were positive for the presence of Toxocara spp. eggs, all from dogs living in islands, and 22/104 (21.15%) dog hair samples contained eggs of Toxocara spp. Environmental contamination with Toxocara spp. eggs was observed in 50/130 (38.46%) samples from all sampled sites. No significant association was found between risk factors (age, sex, educational level, monthly income, owning dogs or cats, ingestion of treated water, and consumption of raw or uncooked meat) and Toxocara spp. seropositivity. The present study is the first concurrent report on people, their dogs, and environmental contamination of Toxocara spp. The high prevalence we observed in the seashore populations of both in island and mainland areas may be caused by exposure to contaminated sand and climatic factors favoring frequent exposure to Toxocara spp. In conclusion, seashore lifestyle and living conditions of both island and mainland areas may have predisposed higher contact with infected pets and contaminated soil, favoring the high prevalence of toxocariasis.

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.

Seroprevalence of Toxocara Infection in Association with Different Risk Factors among Children of 4-12 Years Old Referred to Some Medical Centers in Aras Free Zone, Northwest Iran

Background:

Toxocariosis is a parasitic disease caused by the larval stage of Toxocara species from dog and cat. It has a worldwide distribution with higher prevalence in children. This study aimed to determine seroprevalence of Toxocara infection and its association with some risk factors among children of Aras Free Zone (Jolfa City) in Northwest of Iran.

Methods:

Sera were collected from 514 children aged 4–12 yr old attending to some medical centers in the study area from May 2018 to Feb 2019. Anti-Toxocara IgG antibodies assay was performed using commercial ELISA kit (Nova Tec, Germany). The seropositivity rate was determined and its association with different demographic criteria and risk factors were statistically analyzed.

Results:

The overall seroprevalence was 2.3% (12/514). Risk factors of children’s age group and contact with either pet animals (dog and cat) and/or soil were significantly associated with seropositivity. However, there was not any relationship between Toxocara infection and gender of children, place of residency (urban or rural) and their mothers’ education level.

Conclusion:

Both girls and boys are at risk of Toxocara infection in the study area. Younger age of childhood and contact with sources of infection were important associated factors. More probably, additional criteria are involved in the initiation of infection.

Prevalence of toxocariasis and its related risk factors in humans, dogs and cats in northeastern Iran: a population-based study

BACKGROUND

Toxocariasis is one of the most common zoonotic infections in dogs and cats. The objectives of this study were to determine the prevalence of anti-Toxocara antibodies and identify the epidemiological and clinical features and related risk factors of toxocariasis in the general population along with the prevalence of this infection in dogs and cats in northeast Iran.

METHODS

In this cross-sectional study, anti-Toxocara antibodies from 1150 urban and rural participants were examined using a commercial enzyme-linked immunosorbent assay. In addition, the stool specimens of 538 dogs and 236 cats were tested using the formalin-ether concentration technique. Sociodemographic data and related risk factors were collected using a structured questionnaire and the data on clinical manifestations were obtained from personal health records.

RESULTS

Anti-Toxocara antibodies were detected in 7.2% (83/1150) of the study population. Risk factors for seropositivity based on multivariable analysis were younger age (p=0.019), living in rural areas (p=0.048), occupations with high exposure risk to toxocariasis (p=0.001), contact with dogs or cats (p=0.003), contact with soil (p=0.001), history of geophagy (p=0.001) and the consumption of raw or undercooked liver (p=0.001). The prevalence of symptoms such as asthma, shortness of breath, blurred vision, abdominal pain and epilepsy were significantly higher in seropositive individuals compared with seronegative ones. Toxocara eggs were found in 15.1% (81/538) of dogs and 34.7% (82/236) of cats. A significant relationship was found between infection in dogs and cats and age, type, place of residence and anthelmintic consumption.

CONCLUSIONS

Identification of anti-Toxocara antibodies in the general population and the presence of confirmed infections in dogs and cats indicates exposure to Toxocara infection as a public health problem in northeast Iran.

Urticaria and silent parasitism by Ascaridoidea: Component-resolved diagnosis reinforces the significance of this association

Urticaria remains a major problem in terms of aetiology, investigation, and management, and although parasitic diseases are considered potential causes, the absence of a consistent link between parasitic infections and skin allergy symptoms leads to the need for a deeper study of parameters that support this association. The objectives of this study were to analyse a possible relationship between parasitism by Ascarididae (Toxocara canis and Anisakis simplex) and the clinical expression of urticaria and to identify possible parasitic molecular markers for improving the diagnosis of unknown urticaria aetiology. The prevalence of Toxocara and Anisakis infestations was evaluated by measuring the levels of specific IgG (sIgG) and IgE (sIgE) antibodies against crude extracts and isolated components from whole larvae of Anisakis simplex (Ani s 1, Ani s 3 and Ani s 7) and Toxocara canis (TES-120, TES-70, TES-32 and TES-26) using immunologic and molecular diagnostic methods. A cross-sectional study was performed in a group of 400 individuals. The study group consisted of 95 patients diagnosed with urticaria (55 with chronic urticaria and 40 with acute urticaria). A control group consisted of 305 subjects without urticaria (182 diagnosed with respiratory allergy and 123 without allergy). Statistically significant differences were demonstrated in the seroprevalence of specific IgG and IgE antibodies between the urticaria patients and the healthy general population when isolated ascarid antigens were evaluated. The prevalence of IgG antibodies against Ani s 1, IgE antibodies against TES-120 and IgE antibodies against TES-70 were significantly different between the control individuals (healthy general population) and patients with urticaria. Moreover, the urticaria patient group demonstrated a higher seroprevalence of antibodies (sIgE and sIgG) against Anisakis simplex larva whole extract than the control group but just with statistically diferences when sIgE was evaluated. The presence of IgE and/or IgG antibodies against Ani s 3 (tropomyosin) can help to discriminate between patients with and without urticaria. Both ascarids seem to be associated with urticaria, although in our region, Anisakis seems to have greater involvement than Toxocara in this relationship. Molecular diagnostics can be used to associate urticaria with parasite infestations. Tropomyosin and Ani s 1 were the most relevant markers to demonstrate the association between urticaria and the most relevant Ascarididae parasites in our region.

Toxocara prevalence in dogs and cats in Brazil

I herein review published studies reporting the prevalence of Toxocara infection in dogs and cats in Brazil. Based on data gathered from faecal examinations of approximately 38,940 dogs and 5600 cats from different Brazilian studies, the mean prevalence of Toxocara infection is 11.4% (range: 0.7-48.9%) in dogs and 16.7% (0.3-43.1%) in cats. These mean values based on faecal examinations should be interpreted with cautious, considering the obvious differences in terms of sample size, diagnostic tests and animal populations. Accordingly, necropsy investigations reveal higher mean prevalence values (21.9% for Toxocara canis and 27.6% Toxocara cati in dogs and cats, respectively). The contamination with Toxocara eggs in different environments and the significance of these parasites from a public health perspective in Brazil are briefly discussed.

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.

Risk factors and prevalence of toxocariasis in pregnant women and diabetic patients compared to healthy adults in Ilam province, western Iran

Toxocara is one of the common intestinal nematodes in dogs and cats and is the agent of tissue migratory larvae in humans. Customarily, the prevalence of human toxocariasis hovers around 15.8 % in Iran. Furthermore, other research outcomes demonstrated a tendency for an outbreak of toxocariasis in Iran. Therefore, we carried out a cross-sectional study and assessed the seroprevalence of toxocariasis humans in Ilam Province, western of Iran. A total of 539 serum samples were collected between September 2017 and March 2018 from patients referred to the Health Centers of Ilam province, Iran. Serum samples were investigated for the presence of Toxocara using IgG antibodies, ELISA (Enzyme-Linked Immunosorbent Assay) kit. Risk factors such as contact with cats and dogs, living in rural areas were investigated among the study population. Out of 539 total samples collected, 97 cases (17.99 %) were positive for anti-toxocara IgG antibodies. These antibodies were recovered from serum samples of otherwise healthy adults (15.54 %, 49/296), pregnant women (21.16 %, 40/189) and diabetic patients (14.81 %, 8/54). This study showed significant relationship between toxocariasis and contact with animal pets in all studied groups (P value ≤ 0.05) and a significant relationship between toxocariasis and living in rural areas among pregnant women (P value ≤ 0.05).

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.

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.

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.

Human Toxocariasis: Prevalence and Factors Associated with Biosafety in Research Laboratories

Human toxocariasis is a neglected parasitic disease worldwide. Researchers studying this disease use infectious strains of Toxocara for experiments. Health workers are at risk in the course of their daily routine and must adhere to biosafety standards while carrying out the activities. Researchers on biosafety concerning working with these parasites are insufficient. The aim of this study was to determine the rate of seroprevalence of Toxocara species among health-care research laboratory workers (professors, technicians, and students), and to investigate the risk factors of Toxocara infection associated with laboratory practices. This cross-sectional study involved 74 researchers at two federal universities in southern Brazil from February 2014 to February 2015; 29 researchers manipulated infective strains of Toxocara canis (test group) and 45 did not (control group). Serum samples were examined using enzyme-linked immunosorbent assay. Epidemiological data were obtained via a questionnaire containing information about laboratory routine, eating behavior, and contact with dogs. The seroprevalence of anti-T. canis IgG was 14.9% (11/74; 13.8% [4/29] in the test group and 15.6% [7/45] in the control group). Most individuals in the test group correctly understood the primary mode of infection; however, 13.8% did not use gloves while manipulating T. canis eggs. Knowledge of biosafety must be well understood by health-care professionals doing laboratory work with biological agents. To our knowledge, this is the first study to investigate the rate of seroprevalence of IgG against Toxocara spp. among professionals and students who handle infective forms of the nematode T. canis.

FREQUENCY OF ANTI- Toxocara spp. ANTIBODIES IN INDIVIDUALS ATTENDED BY THE CENTRO DE SALUD FAMILIAR AND ENVIRONMENTAL CONTAMINATION WITH Toxocara canis EGGS IN DOG FECES, IN THE COASTAL NIEBLA TOWN, CHILE

The frequency of anti-Toxocara spp. antibodies in individuals attended by the Centro de Salud Familiar in the coastal Niebla town, Chile, was related to the host and to environmental factors. IgG anti- Toxocara antibodies were detected with a commercial ELISA kit (SCIMEDX Corporation, USA). Samples with undetermined absorbance values were subjected to an additional ELISA standardized by the Instituto de Salud Pública, Chilean Health Ministry, a commercial ELISA (NOVATEC, Germany), and a commercial Western blot kit (LDBio Diagnostics, France). Hematological exams were performed using an automated blood counter and blood smears. Dog feces were collected from the ground along the main road in Niebla, including rural and urban locations. Ninety (25.4%) of the 355 examined individuals were positive by the ELISA test. The frequency of anti-Toxocara antibodies and the infection risk were significantly higher (p < 0.05) among those individuals ≥ 40 years old with respect to the 20-39 years old group, in individuals from rural locations, those who did not have a safe drinking water supply in the house or who presented blood eosinophilia. The proportion of positive samples of dog feces and the mean number of Toxocara canis eggs/g of feces in urban and rural areas were similar (p > 0.05).

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.

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.

Presence of anti-Toxocara canis antibodies and risk factors in children from the Amecameca and Chalco regions of México

BACKGROUND

Toxocariasis is a zoonotic disease that poses a threat to public health worldwide. This disease primarily affects children and is caused by the presence in the digestive tract of a common roundworm of dogs, Toxocara canis, or cats, Toxocara cati. Toxocara is responsible for the presentation of various syndromes in humans depending on the affected organs.

METHODS

In this study, the prevalence of anti-T. canis antibodies was investigated in children aged 3-16 years from semirural populations in the municipalities of Amecameca and Chalco in México. An ELISA was used to determine the presence of anti-T. canis antibodies in blood samples.

RESULTS

Of the 183 sera obtained for this study, 22 were positive for anti-T. canis antibodies (12.02%). Of these, 6.50% were from males and 5.4% were from females. Risk factors were investigated and it was found that living near a cattle operation had a statistically significant association with (Chi(2) = 5.51 and p = 0.01) and was a risk factor for (OR = 4.25, p = 0.02) seropositivity to T. canis. Keeping dogs with short hair (Chi(2) = 3.24 and p = 0.07) showed a tendency toward seropositivity for T. canis, as did the habit of sleeping with pets (Chi(2) = 3.46 and p = 0.06).

CONCLUSIONS

Seropositivity to T. canis was confirmed in children in the Amecameca and Chalco regions of México and the risk factors were identified. These findings provide important insight into the prevalence and spread of this zoonotic parasite.

Seroepidemiology of Toxocara infection in patients with vision impairment and blindness in durango, Mexico

Background

Toxocara infection is a cause of vision impairment and blindness. We aimed to determine the seroprevalence and correlates of Toxocara infection in patients suffering from vision impairment and blindness in Durango City, Mexico.

Methods

Through a cross-sectional seroprevalence study, 204 patients with vision impairment and 19 blind patients were studied for the presence of anti-Toxocara IgG antibodies in Durango City, Mexico. Seroprevalence association with socio-demographic, housing, clinical, and behavioral characteristics of participants was also investigated.

Results

Five (2.5%) of the 204 patients with vision impairment, and none of the 19 patients with blindness were positive for anti-Toxocara IgG antibodies. In total, five of the 223 (2.2%) patients were positive for anti-Toxocara IgG antibodies. Seropositivity to Toxocara was not associated with age, sex, educational level, socio-economic status, presence of underlying diseases or behavioral characteristics of the patients. In contrast, multivariate analysis showed that Toxocara seropositivity was associated with living in a house with soil floor (odds ratio (OR) = 11.14; 95% confidence interval (CI): 1.57 - 78.74; P = 0.01).

Conclusions

This is the first report of Toxocara exposure in patients with vision impairment and blindness in Mexico, and of an association of Toxocara exposure with living in a house with soil floors. Results suggest a low Toxocara exposure in these patients in Durango, Mexico. The risk factor associated with Toxocara exposure identified in this study warrants for further investigation.

Exposure and risk factors to coxiella burnetii, spotted fever group and typhus group Rickettsiae, and Bartonella henselae among volunteer blood donors in Namibia

BACKGROUND

The role of pathogen-mediated febrile illness in sub-Saharan Africa is receiving more attention, especially in Southern Africa where four countries (including Namibia) are actively working to eliminate malaria. With a high concentration of livestock and high rates of companion animal ownership, the influence of zoonotic bacterial diseases as causes of febrile illness in Namibia remains unknown.

METHODOLOGY/PRINCIPAL FINDINGS

The aim of the study was to evaluate exposure to Coxiella burnetii, spotted fever and typhus group rickettsiae, and Bartonella henselae using IFA and ELISA (IgG) in serum collected from 319 volunteer blood donors identified by the Blood Transfusion Service of Namibia (NAMBTS). Serum samples were linked to a basic questionnaire to identify possible risk factors. The majority of the participants (64.8%) had extensive exposure to rural areas or farms. Results indicated a C. burnetii prevalence of 26.1% (screening titre 1∶16), and prevalence rates of 11.9% and 14.9% (screening titre 1∶100) for spotted fever group and typhus group rickettsiae, respectively. There was a significant spatial association between C. burnetii exposure and place of residence in southern Namibia (P<0.021). Donors with occupations involving animals (P>0.012), especially cattle (P>0.006), were also significantly associated with C. burnetii exposure. Males were significantly more likely than females to have been exposed to spotted fever (P<0.013) and typhus (P<0.011) group rickettsiae. Three (2.9%) samples were positive for B. henselae possibly indicating low levels of exposure to a pathogen never reported in Namibia.

CONCLUSIONS/SIGNIFICANCE

These results indicate that Namibians are exposed to pathogenic fever-causing bacteria, most of which have flea or tick vectors/reservoirs. The epidemiology of febrile illnesses in Namibia needs further evaluation in order to develop comprehensive local diagnostic and treatment algorithms.

Risk assessment of flavivirus transmission in Namibia

The role of arboviruses causing acute febrile illness in sub-Saharan Africa is receiving more attention. Reports of dengue in tourists were published nearly 10 years ago in Namibia, but the current epidemiology of arboviruses is unknown and surveys of mosquito vectors have not been carried out since the 1950s. To begin addressing this knowledge gap, a prospective cross-sectional study was conducted using samples from volunteer blood donors linked to questionnaire. Serum samples were tested using a Dengue IgG Indirect ELISA which measured exposure to dengue virus/flaviviruses. Entomological samples were collected from tires during the rainy season (February-March 2012) in six locations across Namibia's capital city, Windhoek. Among 312 blood donors tested, 25 (8.0%) were positive for dengue virus/flavivirus exposure. The only significant risk factor was age group with high exposure rates among those older than 50 (29%) compared with those below 40 years old (between 2.9% and 8.3%) (P<0.002). Larvae and pupae of Aedes aegypti and Culex pipiens complex accounted for 100% of the 2751 samples collected, of which only 12.2% (n=336) were Ae. aegypti. Each site demonstrated high variability of species composition between sampling times. While the significant dengue virus/flavivirus exposure rate among those above 50 years old is likely indicative of the West Nile epidemic in the 70s and 80s, the low exposure among those under 50 suggests that flaviviruses are still circulating in Namibia. While Ae. aegypti and C. pipiens sp. may play a role in future epidemics, the significance of presence may be reduced due to short rain periods, dry, arid, cold winters and policies and social understandings that limit non-structured storage and use of tires in low income areas. Future studies should further characterize the circulating arboviruses and investigate mosquito ecology nationally to map areas at higher risk for future arbovirus outbreaks.

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.

Seroprevalence and modifiable risk factors for Toxocara spp. in Brazilian schoolchildren

BACKGROUND

Toxocariasis is a worldwide helminthic zoonosis caused by infection with the larvae of the ascarid worms that comprise the Toxocara spp. Children are particularly prone to infection because they are exposed to the eggs in sandboxes and playgrounds contaminated with dog and cat feces. Certain behaviors, such as a geophagy habit, poor personal hygiene, a lack of parental supervision, close contact with young dogs, and ingestion of raw meat, as well as gender, age, and socioeconomic status, affect the prevalence of the disease. However, previous studies of the risk factors for toxocariasis have generally produced inconsistent results. An epidemiological cross-sectional study was conducted to evaluate the seroprevalence of IgG anti-Toxocara spp. antibodies and associated factors in schoolchildren from a region in the southeast of Brazil.

METHODOLOGY/PRINCIPAL FINDINGS

A total of 252 schoolchildren aged 1 to 12 years (120 males and 132 females) were assessed. An enzyme-linked immunosorbent assay based on Toxocara canis larval excretory-secretory antigens was used to determine outcomes. A questionnaire was used to collect information on children, family, and home characteristics. Clinical and laboratory data completed the dataset investigated in this study. Seroprevalence was 15.5% (95%CI 11.5-19.8). Geophagy (aPR 2.38 [95%CI 1.36-4.18], p-value 0.029) and the habit of hand washing before meals (aPR 0.04 [95%CI 0.01-0.11], p-value ≤ 0.001) were factors associated with increased and decreased seroprevalence, respectively. The income factor and its related variables lost statistical significance after adjustment with a multiple Poisson regression model.

CONCLUSIONS/SIGNIFICANCE

The current study confirms that toxocariasis is a public health problem in the evaluated area; modifiable factors such as soil contact and personal hygiene appear to have a greater influence on the acquisition of infection than sociodemographic attributes, thus representing direct targets for disease prevention and control.