Seroepidemiological study for toxocariasis among children in Zanjan-northwest of Iran

Prevalence, Infection, and Risk to Human Beings of Toxocara canis in Domestic Food-Producing Animals

Toxocariasis is a significant food-borne zoonotic parasitic disease, and a range of birds and mammals are the paratenic hosts of Toxocara canis. The consumption of raw or undercooked meat and viscera of these paratenic hosts frequently leads to T. canis infection and the development of human toxocariasis. In this review, we will perform an analysis of relevant papers published in the National Center for Biotechnology Infrastructure database on the parasitism, migration, and infection of T. canis in chickens, pigeons, quail, pigs, cattle, sheep, and other food-producing animals, so as to make the public aware of the risk factors of human toxocariasis, improve the public's understanding of T. canis infection, and provide evidence for targeted prevention and control measures.

Toxocara Infection in Dogs and Cats in Isfahan Province of Iran in 2021

Background

Toxocariasis is an acute or chronic disease caused by parasites of the Ascaridae family, especially Toxocara of dogs and cats. Eggs are excreted out by feces of these animals on soil. Infective eggs develop on soil which can be infective to human. In this study, infection rate of Toxocara spp. in dogs and cats of urban and rural areas of Isfahan province of Iran has been investigated.

Materials and Methods

Three hundred and seventy-five stray dog feces and 230 stray cat feces were collected from the public environment (slaughterhouses, parks, children's playgrounds, student dormitories, university environment, streets and squares) in Isfahan province of Iran. At first, dogs' and cats' feces were examined for the presence of Toxocara spp. eggs using formalin ether method. In the second stage, by using molecular methods, Toxocara eggs spp. (Toxocara canis or Toxocara cati) were identified.

Results

From 375 dog fecal samples, 39 (10.40%) and from 230 cat fecal samples, 38 (16.52%) were positive for presence of the Toxocara eggs.

Conclusion

Dogs and cats in Isfahan province of Iran were infected with Toxocara parasite. These infections can be potential risk for human toxocariasis.

Detection of Toxocara species larvae in four Iranian free-range broiler farms

BACKGROUND

The epidemiology of Toxocara canis and Toxocara cati in food animals, associated products, and their zoonotic potential are poorly understood. A cross sectional study was designed to determine the prevalence of Toxocara spp. larvae from free-range broiler chickens in traditional farms using conventional techniques and molecular method. Eight-hundred tissue samples including liver, gizzard, lungs and heart were collected from 200 chickens belonging to different regions of Zanjan Province, Iran and were processed by conventional and molecular methods.

RESULTS

Out of 800 chicken tissues, 49 samples (6.1%) were positive for nematode larvae. Polymerase chain reaction was performed to identify species-specific of Toxocara larvae. The findings showed that 10.5% (21 out of 200) chickens were infected with Toxocara species, so that 57.1% (12 out of 21) of the samples were positive for Toxocara canis and 42.9% (9 out of 21) of the samples were positive for Toxocara cati.

CONCLUSION

Considering the significant contamination/infection of free-range broiler chickens with Toxocara larvae, the consumption of chicken meat and viscera, especially liver and gizzards, can play an important role in the transmission of infection to humans. Prevention and control measures focused on regular deworming of dogs and cats, increasing public awareness of Toxocara infection are recommended.

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.

Seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran

The World Health Organization has categorized toxocarosis as a neglected tropical disease despite its significant impact on high-risk groups such as children. This study aimed to investigate the seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran. A total of 386 children were enrolled in the study. All serum samples were tested for the presence of IgG antibodies against Toxocara spp. infection using an enzyme-linked immunosorbent assay. Moreover, relevant risk factors and clinical symptom data were obtained using questionnaires. Data analysis was performed using the SPSS software version 24. The overall seroprevalence of Toxocara spp. infection was found 2.85 % (11/386). However, Toxocara spp. infection was high for some risk factors, including eating soil (14.3 %), contacting cats (6.7 %), and consuming raw vegetables (3.7 %). However, there were no statistically significant differences regarding the risk factors and socio-demographic characteristics. Considering the clinical symptoms, Toxocara spp. infection was different in children with eosinophilia (20 %), ocular disorders (8.3 %), skin disorders (7.7 %), liver disorders (4.5 %), and stomach ache (4.2 %), although not statistically significant. The results revealed that the seroprevalence of Toxocara spp. infection was relatively low in children in northern Iran. It is suggested to conduct more studies in different parts of Iran to gain a deeper understanding of the toxocarosis seroprevalence and its status in high-risk groups such as children with asthma, hypereosinophilic syndrome, allergic skin disorders, and epilepsy.

Seroprevalence of Toxocara spp. in children (3-13 years old) in Zahedan, Southeast of Iran

Child Toxocariasis (CT) is one of the most important helminthic parasitic diseases in Iran. The current study was aimed to determine the seroprevalence of toxocariasis in children in Zahedan, southeast of Iran. In this cross-sectional study, serum samples of 373 children aged 3-13 years old referred to health centers in Zahedan were collected randomly with criteria based on the parameters that were used in earlier studies and examined for anti-Toxocara antibody using a commercial ELISA kit. Of the 373 recruited subjects, 206 (55.2%) were male and 167 (44.8%) were female. Most of the subjects (36.5%) were in the age group 3-4 years old. Anti-Toxocara antibodies were detected in the sera of five out of 373 individuals, corresponding to a seroprevalence rate of 1.3%. A significant correlation was found between the incidence of disease and eosinophilia, a history of contact with dogs or cats, as well as the consumption of raw vegetables and drinking of contaminated water. There was no significant correlation between prevalence and gender or age. The finding of this study revealed that the prevalent CT is relatively low in Zahedan region. The rate of CT infection in the southeast of Iran was lower than the rate in other parts of Iran.

Seroepidemiological Study of Toxocariasis in Children Aged 6-14 Year Old in Sanandaj, Western Iran

Background:

Toxocariasis is a disease caused by Toxocara nematodes and occurs from consuming their eggs. The main hosts of these worms are dogs and cats. The disease in humans becomes a visceral larva migrans (VLM). This descriptive cross-sectional study was conducted to determine the prevalence of toxocariasis in children aged 6–14 years.

Methods:

This cross-sectional descriptive study was conducted from Jun 1 2016 to Dec 1 2017 in Sanandaj, west of Iran. A total of 182 serum samples were collected from children age 6 to14 yr referred to medical diagnostic laboratories. Demographic data (age, sex, and parents’ literacy status), clinical signs (cough, headache, fever, abdominal pain), and the history of contact with dogs and cats was collected by a questionnaire. The presence of anti-Toxocara IgG antibody was detected by T. canis IgG ELISA (IBL, Germany) kit.

Results:

Of 182 subjects, 97 (53.3%) were male and 85 (46.7%) female. The average age was 9.2 years. Antibodies against T. canis were positive in three cases (1.65%) of all the studied subjects.

Conclusions:

The results showed a low prevalence of toxocariasis in children studied.

A Systematic Review and Meta-analysis of Toxocariasis in Iran: Is it Time to Take it Seriously?

BACKGROUND

Toxocariasis is one of the neglected zoonosis with considerable public health importance around the world. The current study aimed to elucidate the overall prevalence of Toxocara infection in human and definitive hosts and also the contamination of soil and raw vegetables with the ova of these parasites, in Iran, using systematic review and meta-analysis.

METHODS

Six English and Persian databases were explored from 2000 to 2017 using the terms toxocariasis, Toxocara spp., visceral larva migrans, Iran, epidemiology, and prevalence. This meta-analysis conducted using STATA, and for all statistical tests, a p value less than 0.05 was considered significant. The random-effects model was used to the report of the pooled prevalence with a 95% confidence interval (CI).

RESULTS

The pooled prevalence of toxocariasis in human was calculated as 11% (95% CI 8-13%). In terms of definitive hosts, the pooled prevalence of Toxocara infection in dogs and cats were calculated as 17% (95% CI 14-20%) and 37% (95% CI 26-48%), respectively. Also, the pooled prevalence of Toxocara spp. eggs in the soil and raw vegetable samples were calculated as 18% (95% CI 13-23%) and 2% (95% CI 1-3%), respectively.

CONCLUSIONS

The results of current study demonstrate that toxocariasis should be taken more seriously by health authorities. Implementing an appropriate control program is necessary to reduce the incidence of this disease in Iran.

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.

Seroprevalence of ToxocaraCanis in Asthmatic Children and its Relation to the Severity of Diseases - a Case-Control Study

Background

Toxocariasis is a common parasitic infectionworldwide even in developed countries. Through this health problem, the immune system is triggered and the antibody is produced, leading to some hypersensitive situations like asthma. In the present study, we tried to show a correlation between Toxocara Canis (T. canis) seropositivityand asthma in Isfahan city.

Methods

This research is a cross-sectional study involving 40 asthmatics and 46 non-asthmatic cases aged 2-18 years. In all cases, T. canis IgG level was measured using enzyme-linked immunosorbent assay (ELISA) and compared between two groups.

Results

The seroprevalence of IgG anti-T. canis antibodies were 45%in the asthmatic patients and 21.7% in thecontrols (P= 0.022). The more severe asthmatic patients had significantly more risk for T. canis seropositivity (P= 0.019). In the asthmatic patients, there was a significant correlation between Toxocara seropositivity and goingto park or playground (P= 0.001).

Conclusion

In this study, we found a significantly positive serology of T. canis in asthmatic children especially in more severe disease. To verify the etiologic role of Toxocara in asthma, more advanced studies are needed.

Molecular characterization of Toxocara spp. eggs isolated from public parks and playgrounds in Shiraz, Iran

Human toxocariasis, a worldwide parasitic disease, is caused by the larval stage of intestinal nematodes of dogs and cats, namely Toxocara canis and Toxocara cati. Human infection occurs by the accidental ingestion of embryonated eggs present in the soil, vegetables or on other contaminated surfaces, as well as via consumption of uncooked paratenic hosts, such as bird meat and giblets. The objective of this study was to evaluate the contamination of soil in public parks and playgrounds in Shiraz using microscopy and molecular methods. A total of 150 soil samples were collected from public parks and playgrounds in various areas of Shiraz, southern Iran. The samples were treated with saturated zinc sulphate solution, and Toxocara spp. eggs were detected by microscopic observation followed by nested polymerase chain reaction (PCR). To differentiate T. canis and T. cati eggs from each other, PCR restriction fragment length polymorphism (RFLP) of the internal transcribed spacer (ITS)-rDNA region by SalI endonuclease enzyme was used. PCR-sequencing was performed to confirm the results of the PCR-RFLP method. Based on the flotation results of the 150 soil samples, six (4%) were found to be positive for Toxocara spp. eggs, whereas nested-PCR showed 24 samples to be positive (16%). Based on the PCR-RFLP method and the sequence of the ITS-rDNA region, a total of 23 out of 24 isolates were confirmed as T. cati and one out of 24 as T. canis. The results showed a higher number of soil samples to be positive for Toxocara by the molecular method than microscopy, and higher T. cati infection in soil samples, which could have an important role in human infection with toxocariasis in this region.

Dogs' Gastrointestinal Parasites and their Association with Public Health in Iran

INTRODUCTION

Dogs harbour zoonotic parasites that cause serious infections in humans, such as visceral larva migrans, ocular larva migrans, cystic echinococcosis, and alveolar echinococcosis. Studies on dogs' gastrointestinal parasites in different geographical locations are required to increase knowledge of the risk of canine zoonoses in human populations.

MATERIAL AND METHODS

The presence of parasites was examined in 450 faecal samples collected from eight zones of Zanjan province, northwest Iran from June to November 2015. The samples were examined using the sedimentation concentration method and modified Ziehl-Neelsen staining.

RESULTS

Gastrointestinal parasites were found in 86 (19.1%) faecal samples. Sarcocystis spp. (7.3%), Taenia/Echinococcus spp. (5.6%), Toxocara spp. (1.8%), and Cystoisospora spp. (1.6%) were the most common parasites observed. The other detected parasites consisted of Dicrocoelium dendriticum (0.7%), Eimeria spp. (0.7%), Cryptosporidium spp. (0.4%), Physaloptera spp. (0.4%), Giardia spp. (1.3%), and Spirocerca lupi (1.3%). The lowest parasite infection rates belonged to Trichuris vulpis and Acanthocephalans (0.2% each).

CONCLUSION

This study provides current information on the infection rates in dog populations in Zanjan Province. Furthermore, the study shows a high prevalence of gastrointestinal parasitic infections, including zoonotic ones and particularly Taenia/Echinococcus spp., potentially transmissible to humans and thus relevant to public health.

Latent and Asymptomatic Toxocara Infection among Young Population in Northwest Iran: The Necessity of Informing People as a Potential Health Risk

Objectives. This study was designed to determine the frequency of anti-Toxocara antibodies in youngsters aging from 2 to 20 years in northwest Iran. Materials and Methods. 397 samples were taken randomly almost equally from four locations in Urmia, west Azerbaijan, during August 2014 to September 2015. Anti-Toxocara IgG antibody assays were done on sera by using ELISA kit (IBL, Germany). In order to prevent cross-reaction, the samples of the patients who are infected with other parasites in stool exam, especially Ascarididae family, were also excluded. SPSS 16.0 software was used for statistical analysis. Results. 12 (3%) of the serum samples were positive for anti-Toxocara IgG. According to the Chi-square analysis, risk factors such as mother's educational level, keeping dogs or cats as pets, and history of coughing were related to Toxocara infection (P < 0.05). There was no relationship between toxocariasis and gender, history of onychophagy, pica, fever, abdominal pain, and anorexia; however, we found a significant relationship between Toxocara infection and chronic coughing (P = 0.045). Conclusion. Toxocariasis in northwest Iran can be considered as a public health problem. This study may also help to increase the awareness about this infection.