Seroprevalence of human toxocariasis in Andean communities from the Northeast of Lima, Peru

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.

Status of human toxocariasis, a neglected parasitic zoonosis in Iran: a systematic review from past to current

Although human toxocariasis can lead to serious complications including neurological, ocular and visceral complications, there is a lack of comprehensive epidemiological information about the seroprevalence of Toxocara species in humans. In the present study, we analysed and reviewed the overall seroprevalence of human toxocariasis in Iran. The data collection was systematically undertaken on published articles using the PubMed, Google Scholar, ScienceDirect and Scopus databases. A total of 27 studies from the past two decades reporting seroprevalence of human toxocariasis met our eligibility criteria. The pooled proportion of Toxocara infection was estimated as 6.58% (95% confidence interval = 3.98-9.77). A wide variation between different studies was observed (Q statistic = 799.37, df = 26, P < 0.0001, and I² = 96.7%). The seroprevalence rate of toxocariasis in the Iranian population is relatively high; contamination of the environment by eggs from the host as well as from household dogs and cats should be blamed.

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.

Intestinal Parasites of Pets and Other House-kept Animals in Moscow

A study screening pet animals (dogs, cats, chinchillas, ferrets, guinea pigs, rabbits, primates, reptiles, and hedgehogs) within Moscow city limits for intestinal parasitic diseases has been conducted over a period of 6 years. According to the study, parasitic infections caused by intestinal protozoa are found in pet animals more frequently than by intestinal helminths. Although dogs and cats exhibit the highest level of diversity of intestinal parasite species, in the group of exotic animals, helminth infection are found much less frequently and parasitic fauna is represented mostly by intestinal protozoa with a high percentage of mixed infection. The most widespread helminth infeсtion of dogs and cats is toxocarosis (respectively 2.5 and 5.7 %) and the most widespread protozoan infection is Giardia sp. (9.8 and 4.6 %). Giardia sp. was found in 47.4 % of chinchillas, Cryptosporidium sp. was more frequently found in ferrets (6.55 %), protozoa from the family Trichomonadida was found in guinea pigs (9 %), Eimeria sp. in rabbits (13.9 %), Acanthocephala in primates (15.7 %), and eggs from the generaOxyurida (59 %), along with protozoa from the family Trichomonadida, in reptiles. Capillaria sp. was most prevalent in hedgehogs (33.4 %). Acanthocephala eggs, as well as protozoa from the Giardia and Entamoeba genera, were more frequently found in primates. Parasites common to animals and humans, which may become a source of infection for the latter under certain conditions, have been identified in pet animals.

Production and evaluation of the recombinant antigen TES-30 of Toxocara canis for the immunodiagnosis of toxocariasis

INTRODUCTION

Toxocara canis is a pathogenic nematode of canines which can be accidentally transmitted to humans. Although serology is the most important diagnostic tool for this zoonosis, diagnostic kits use crude excretion/secretion antigens, most of them being glycoproteins which are not species-specific and may cross-react with antibodies generated against other parasites. 

OBJECTIVES

To produce the rTES-30 recombinant antigen of Toxocara canis and evaluate it in the immunodiagnosis of toxocariasis. 

MATERIALS AND METHODS

The gene that codes for TES-30 was cloned in the expression vector pET28a (+) using single-stranded oligonucleotides united by PCR. The protein rTES-30 was purified by Ni2+ affinity chromotography. Seroreactivity of rTES-30 was evaluated by immunoblot. Given that there is no gold standard test, the behaviour of the antigen was compared with the method that is routinely used to immunodiagnose toxocariasis, i.e., the conventional ELISA technique using excretion/secretion antigens. 

RESULTS

The rTES-30 was produced from an Escherichia coli LB culture which yielded 2.25 mg/L of the antigen with a purity of 95%. The results obtained showed 73% (46/63) concordance of reactivity between the rTES-30 immunoblot and the conventional ELISA, and 100% concordance with the nonreactive sera (21). Nineteen of the 21 sera positive for other parasitoses reacted with ELISA, while only seven of these were positive with the rTES-30 immunoblot. Concordance between the ELISA and the immunoblot was moderate (kappa coefficient: 0.575; 95% CI: 0.41- 0.74). 

CONCLUSIONS

The data presented show the potential of the rTES-30 inmunoblot for confirmation of possible ELISA positives, not only in epidemiological studies, but also as a candidate for the development of diagnostic tests for ocular toxocariasis in Colombia.

The relation between the prevalence of soil transmitted parasites in the soil and among school children in Zagazig district, Sharkyia Governorate, Egypt

Soil transmitted helminths are highly prevalent throughout the developing countries of the world and Egypt is categorized as one of the developing countries. This study aimed to detect the relation between the presence and prevalence of STH in the soil and their reflection on the prevalence among school-children living in rural and urban areas in Zagazig district, Egypt. The present study was carried out on (859) school-children aged 6-13 years in Zagazig district all over the year 2013. They were subjected to stool examination. Out of them 100 suspected children were serotested for anti-TES IgG antibodies Toxocara spp. Soil samples also were collected from their places and regions. The results showed overall prevalence of parasitic infections was 21.07 % for helminthic infection and 39.46 % for protozoa. The prevalence of parasitic infections was more among children in rural areas (28, 49.2, 11.1 %) than those who live in urban areas (6.4, 18, 2.2 %) for helminths, protozoa and Toxocara as the most prevalent helminth respectively. Highly significant association was found between soil-transmitted helminthic infections detected by stool examination of the studied children group and the prevalence of geohelminthes in the examined soil samples, taken from residency areas of those children. This association was missed regarding protozoal infections. According to the results, low level of education and consequently poor socio-economic and hygienic conditions of families appear to be powerful determinants of infection. Thus, improving environmental sanitation is imperative for the control of soil-transmitted helminths.

Toxocariasis in waste pickers: a case control seroprevalence study

BACKGROUND

The epidemiology of Toxocara infection in humans in Mexico has been poorly explored. There is a lack of information about Toxocara infection in waste pickers.

AIMS

Determine the seroepidemiology of Toxocara infection in waste pickers.

METHODS

Through a case control study design, the presence of anti-Toxocara IgG antibodies was determined in 90 waste pickers and 90 age- and gender-matched controls using an enzyme-linked immunoassay. Associations of Toxocara exposure with socio-demographic, work, clinical, and behavioral data of the waste pickers were also evaluated.

RESULTS

The seroprevalence of anti-Toxocara IgG antibodies was significantly higher in waste pickers (12/90: 13%) than in control subjects (1/90: 1%) (OR = 14; 95% CI: 2-288). The seroprevalence was not influenced by socio-demographic or work characteristics. In contrast, increased seroprevalence was found in waste pickers suffering from gastritis, and reflex and visual impairments. Multivariate analysis showed that Toxocara exposure was associated with a low frequency of eating out of home (OR = 26; 95% CI: 2-363) and negatively associated with consumption of chicken meat (OR = 0.03; 95% CI: 0.003-0.59). Other behavioral characteristics such as animal contacts or exposure to soil were not associated with Toxocara seropositivity.

CONCLUSIONS

1) Waste pickers are a risk group for Toxocara infection. 2) Toxocara is impacting the health of waste pickers. This is the first report of Toxocara exposure in waste pickers and of associations of gastritis and reflex impairment with Toxocara seropositivity. Results warrant for further research.

Seroepidemiology of toxocariasis in a rural Tepehuanos population from Durango, Mexico

The epidemiology of toxocariasis in humans in Mexico has been poorly explored. There is a lack of information about toxocariasis in Tepehuanos, an indigenous ethnic group in Durango State in northern Mexico. Therefore, the presence of anti-Toxocara immunoglobulin (Ig) G antibodies was determined in 126 rural Tepehuanos using an enzyme-linked immunoassay. Socio-demographic, clinical and behavioural data of the participants were also obtained. Of the 126 Tepehuanos assessed (mean age 32.46 ± 17.36 years), 33 (26.2%) had anti-Toxocara IgG antibodies. Multivariate analysis showed that Toxocara seropositivity was associated with unemployment (students and housewives) (odds ratio (OR) = 3.1; 95% confidence interval (CI) 1.25–7.47). Other socio-demographic and behavioural characteristics, including age, educational level, contact with animals or soil, consumption of unwashed raw fruits and vegetables or untreated water, were not associated with Toxocara seropositivity. Clinical data were similar in seropositive and seronegative Tepehuanos. These results indicate that Toxocara exposure is common among Tepehuanos but Toxocara does not appear to impact on the health of the population. This is the first report of toxocaral infection in Tepehuanos, and of an association of toxocariasis in adults with unemployment. Further research is needed to elucidate the routes of transmission of Toxocara in Tepehuanos, including the role of hygiene practices, canine and feline contacts, paratenic hosts and soil contamination with infective Toxocara eggs.

A case report of ocular toxocariasis

Ocular toxocariasis is prevalent among children. The symptoms and signs may mimic other ocular pathologies such as malignancies and other infectious diseases (such as toxoplasmosis and syphilis). We presented a case of progressive blurring of vision in a single eye of a 9-year-old boy. The presence of anti-toxocara antibody in serum samples helps to confirmation the diagnosis in our patient. Despite of treatment, the boy had lost his vision on the affected eye.