Risk factors associated with toxoplasmosis and toxocariasis in populations of children from nine cities in southern Brazil

Serosurvey of Toxoplasma gondii and Toxocara spp. co-infection in pregnant women in low-income areas of Brazil

Introduction

Despite human toxoplasmosis and toxocariasis having been listed among the top six most neglected parasitic zoonoses worldwide, presenting similar associated risk factors and transmission routes, few studies have been conducted in pregnant women and the consequences of concurrent infection remain to be fully established. Accordingly, the present study has serologically assessed the co-infection and associated risk factors for Toxoplasma gondii and Toxocara spp. in pregnant women, assisted by the public Unified National Health System (SUS) in southeastern Brazil.

Materials and Methods

Blood samples were collected and tested for IgG antibodies against Toxoplasma gondii by chemiluminescence immunoassay and against Toxocara spp. by enzyme-linked immunosorbent assay (ELISA). An epidemiological questionnaire was applied to gather socioeconomic information to assess the risk factors associated with seropositivity to toxocariasis/toxoplasmosis by univariate analysis followed by logistic regression.

Results

Overall, seropositivity was 69/280 (24.6, 95% CI: 19.96-30.01) for T. gondii and 56/280 (20.0, 95% CI: 15.73-25.08) for Toxocara spp. Co-infection was observed in 25/280 (8.9, 95% CI: 6.12-12.85) pregnant women, with increased odds (OR: 3.3, CI 95%: 1.77-6.14, p = 0.0002). Logistic regression revealed that a higher educational level (high school or college) significantly reduced the likelihood of co-infection seropositivity, owning cats increased the odds of toxocariasis, and older pregnant women presented significantly higher T. gondii seropositivity.

Conclusion

Co-infection herein highlights the importance of educational programs in the prevention of toxocariasis and toxoplasmosis in pregnant women and other high-risk populations.

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.

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.

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.

Frequency of enteroparasitic infections and serum positivity for Toxocara spp. in children from a public day care center in Southern Brazil

INTRODUCTION

Day care centers play an important social role in children's early education and development. The objective of this study was to investigate the frequency of intestinal parasitic infections and infection with Toxocara spp. in children from a day care center in the city of Rio Grande, Rio Grande do Sul, Brazil. Methods: The study was conducted using fecal samples from 50 children, ages three to six years, using Ritchie, Faust, Rugai, and Kinyoun's techniques. A closed and structured epidemiological questionnaire was used to collect data from the parents/guardians of the children. Serological studies for detection of antibodies to Toxocara spp. by immunoenzymatic assays using Toxocara excretion and secretion antigen (TES) were conducted on sera collected from 41 children. Results: The frequency of enteroparasites was 18%, with 43.9% of the children testing seropositive for Toxocara spp. Low family income and low literacy levels of parents/guardians were common factors between the families of the parasite-positive children. For the children who tested positive for Toxocara spp., most of the parents/guardians reported using only water for sanitizing raw vegetables and fruits. Conclusions: The high seropositivity rates for Toxocara spp. indicate that children were exposed to this parasite, and it is important to reduce the risk of infection. In addition, the seropositivity for enteroparasites and the interviews with the parents/guardians indicate the need to educate the studied population regarding the modes of intestinal parasite transmission and the prophylactic measures needed to prevent their dissemination.

Interaction of Toxoplasma gondii infection and elevated blood lead levels on children's neurobehavior

A chronic infection caused by Toxoplasma gondii was considered asymptomatic in immunologically healthy humans, but results from animal and epidemiological studies led to a reconsideration of this assumption. The objective of this study was to evaluate the seroprevalence of T. gondii infection and its possible effects on the behavior of school-aged children in Bahia, Brazil. Serum anti-body determinations were performed by Enzyme-linked Immunosorbent Assay (ELISA). Blood lead levels (BLL) were measured by graphite furnace atomic absorption spectrometry (GFAAS). The evaluation of a child's behavior was assessed using the Child Behavior Check List (CBCL). Multivariate models applying logistic regression were used to test the association of chronic T. gondii infection and BLL with behavioral outcomes in children. Seroprevalence for anti-T. gondii IgG antibody was 43.7 % (95 %-CI: 35.8-51.9). Significant associations between chronic T. gondii infection and total behavioral problems (OR = 2.50; 95 %-CI: 1.06-5.88), internalizing spectrum problems (OR = 4.35; 95 %-CI: 1.11-17.14) and rule breaking (OR = 2.61; 95 %-CI: 1.12-6.05) were observed. A possible interaction between toxoplasmosis prevalence and lead exposure was detected. Children with above the median BLL and positive for IgG anti-T. gondii showed a 5.51-fold increase (95 %-CI: 1.75-17.38) in the chance of displaying disobedient behavior. The results suggest that T. gondii infection may be contributing to the high indices of behavioral changes. Moreover, these findings are the first evidence for a possible interaction between chronic T. gondii infection and elevated blood lead levels on children's neurobehavior.

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.

Toxoplasma gondii infection in children with lymphoma in Eastern China: seroprevalence, risk factors and case-control studies

Epidemiological data for Toxoplasma gondii regarding malignancy have gained increasing attention; however, the information about T. gondii infection among children with malignant lymphoma (ML) in China is unclear. Therefore, 314 children with lymphoma and 314 healthy children, age- and gender-matched, were recruited to estimate the seroprevalence of T. gondii in the participants and identify the risk factors of infection. Blood samples from all participants were collected and examined for T. gondii IgG and IgM antibodies using ELISA. The results showed that the overall seroprevalence of T. gondii antibodies (including IgG and/or IgM) in ML patients and healthy controls was 19.8% and 9.9%, respectively. Contact with the cats, consumption of oysters and history of chemotherapy were estimated to be the risk factors for T. gondii infection in children with lymphoma by multivariable logistic regression analysis, whereas in healthy children, contact with cats and consumption of oysters were the risk factors. Moreover, among various histological types of lymphoma, individuals with NK/T-cell lymphoma, B-small lymphocytic lymphoma, marginal zone B-lymphoma and Hodgkin's lymphoma had a higher seroprevalence than healthy controls (P < 0.05). These findings indicated the high prevalence of T. gondii infection in children with lymphoma, and hence, efforts should be performed to evaluate the effect of the infection further in lymphoma patients.

Seroprevalence of Toxoplasma gondii among School Children in Pyin Oo Lwin and Naung Cho, Upper Myanmar

Toxoplasma gondii is an apicomplexan parasite that can cause toxoplasmosis in a wide range of warm-blooded animals including humans. In this study, we analyzed seroprevalence of T. gondii among 467 school children living in the rural areas of Pyin Oo Lwin and Naung Cho, Myanmar. The overall seroprevalence of T. gondii among school children was 23.5%; 22.5% of children were positive for T. gondii IgG, 0.4% of children were positive for T. gondii IgM, and 0.6% of children were positive for both T. gondii IgG and IgM. Geographical factors did not significantly affect the seroprevalence frequency between Pyin Oo Lwin and Naung Cho, Myanmar. No significant difference was found between males (22.2%) and females (25.0%). The overall seroprevalence among school children differed by ages (10 years old [13.6%], 11–12 years old [19.8%], 13–14 years old [24.6%], and 15–16 years old [28.0%]), however, the result was not significant. Polymerase chain reaction analysis for T. gondii B1 gene for IgG-positive and IgM-positive blood samples were negative, indicating no direct evidence of active infection. These results collectively suggest that T. gondii infection among school children in Myanmar was relatively high. Integrated and improved strategies including reinforced education on toxoplasmosis should be implemented to prevent and control T. gondii infection among school children in Myanmar.

Seroprevalence and risk factors of Toxoplasma gondii infection in children with leukemia in Shandong Province, Eastern China: a case-control prospective study

Limited information is available concerning the epidemiology of Toxoplasma gondii infection in children with leukemia in Eastern China. Therefore, a case-control study was conducted to estimate the seroprevalence of toxoplasmosis in this patient group and to identify risk factors and possible routes of infection. Serum samples were collected from 339 children with leukemia and 339 age matched health control subjects in Qingdao from September 2014 to March 2018. Enzyme linked immunoassays were used to screen anti- T. gondii IgG and anti- T. gondii IgM antibodies. Forty-eight (14.2%) children with leukemia and 31 (9.1%) control subjects were positive for anti-T. gondii IgG antibodies (P < 0.05), while 13 (3.8%) patients and 14 (4.1%) controls were positive for anti-T. gondii IgM antibodies (P = 0.84). Multivariate analysis showed exposure to soil and a history of blood transfusion were risk factors for T. gondii infection. Compared with IgG, patients with a history of blood transfusion were more likely to present anti- T. gondii IgM (P = 0.003). Moreover, patients with chronic lymphocytic leukemia and acute lymphocytic leukemia had higher T. gondii seroprevalence in comparison to control subjects (P = 0.002 and P = 0.016, respectively). The results indicated that the seroprevalence of T. gondii infection in children with leukemia is higher than that of healthy children in Eastern China. This information may be used to guide future research and clinical management, and further studies are necessary to elucidate the role of T. gondii in children with leukemia.

Seroprevalence of Toxoplasma gondii and Toxocara canis in a human rural population of Southern Rio Grande do Sul

Due to the growing population of pets, especially homeless dogs and cats, zoonoses still represent a significant public health problem. Toxoplasma gondii and Toxocara spp. are epidemiologically important zoonotic agents as they are etiological factors of human toxoplasmosis and toxocariasis, respectively. These parasites remain neglected even though they are substantially prevalent in rural areas. The aim of this study was to investigate T. gondii and T. canis seroprevalence and risk factors of seropositivity in a rural population in Pelotas municipality, Brazil. The study participants (n=344) were patients of a Basic Healthcare Unit (BHU) located in Cerrito Alegre. Blood samples were collected and tested for T. gondii antibodies by indirect immunofluorescence and T. canis antibodies by an indirect ELISA that targets an excreted-secreted antigen (TES). T. gondii seropositivity was 53.2%, with higher titers (1:256 - 1:1,024) in individuals who habitually eat pork, beef, or chicken, while T. canis seropositivity was 71.8% and concomitant T. gondii and T. canis seropositivity was 38.3%. Among the seropositivity risk factors assessed, only habitual undercooked meat consumption was significant (p = 0.046; OR = 3.7) for T. gondii and none of them were associated with T. canis seropositivity. Both parasites have a high prevalence in rural areas, which reinforces the need to invest in rural community education and health.

Risk and other factors associated with toxoplasmosis and toxocariasis in pregnant women from southern Brazil

Toxoplasmosis causes complications during pregnancy that have serious effects on fetal development. Thus far, toxocariasis has been reported to spread only via vertical transmission. Nonetheless, the population of pregnant women is also exposed to this infection. Co-infection with both Toxoplasma gondii and Toxocara spp. has been reported in children, but there are no reports of co-infection in the population of pregnant women. The aim of this study was to determine the prevalence of co-infection with T. gondii and Toxocara spp. in pregnant women at a university hospital in southern Brazil, and to identify the risk factors associated with infection by both parasites. Two hundred pregnant women were tested for the presence of anti-T. gondii and anti-Toxocara spp. antibodies and were asked to complete an epidemiological questionnaire. In this study, the co-infection rate observed in the total population of pregnant women was 8%. In addition, women with a positive result for a serology test for Toxocara spp. were at increased risk of infection by T. gondii (P = 0.019). Co-infection with both parasites in pregnant women was associated with low birth weights in neonates. The similar modes of transmission of both parasites could explain the co-infection. Only a few previous studies have investigated this phenomenon. The findings of the present study emphasize the importance of serological diagnosis during prenatal care and further research in this area to identify risk factors associated with this co-infection, and the possible implications of this co-infection during pregnancy and on the health of newborns.

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.

Malaria endemicity and co-infection with tissue-dwelling parasites in Sub-Saharan Africa: a review

Mechanisms and outcomes of host-parasite interactions during malaria co-infections with gastrointestinal helminths are reasonably understood. In contrast, very little is known about such mechanisms in cases of malaria co-infections with tissue-dwelling parasites. This is lack of knowledge is exacerbated by misdiagnosis, lack of pathognomonic clinical signs and the chronic nature of tissue-dwelling helminthic infections. A good understanding of the implications of tissue-dwelling parasitic co-infections with malaria will contribute towards the improvement of the control and management of such co-infections in endemic areas. This review summarises and discusses current information available and gaps in research on malaria co-infection with gastro-intestinal helminths and tissue-dwelling parasites with emphasis on helminthic infections, in terms of the effects of migrating larval stages and intra and extracellular localisations of protozoan parasites and helminths in organs, tissues, and vascular and lymphatic circulations.