eggs isolated from public parks and playgrounds in Shiraz, Iran

First Sero-Molecular Diagnosis of Toxoplasma gondii and Toxocara spp. Infections in the Police Dogs and Their Trainers in Iran

PURPOSE

Toxoplasma gondii (T. gondii) and Toxocara spp. are two types of parasites that can infect humans and various animals, including dogs. Police dogs and their trainers have a vital role in law enforcement, and their health and well-being are crucial for them to effectively carry out their duties. No study has yet been conducted on the prevalence of T. gondii and Toxocara spp. infections among police dogs and their trainers in Iran. The objective of this study was to determine the sero-molecular prevalence of T. gondii and Toxocara spp. infections in police dogs and their trainers in Tehran, the capital of Iran.

METHODS

In Tehran province, the anti-narcotics police have nearly 200 well-trained police dogs. Each dog is assigned a dedicated trainer and upon completing missions, is housed separately in a designated area. In the present study, a total of 150 samples were gathered. These included 50 blood samples from randomly selected police dogs, 50 fecal samples from the same dogs, and 50 blood samples from their trainers. The Modified Agglutination Test (MAT) was performed to detect T. gondii antibodies in dog blood samples and the ELISA system was utilized to identify anti-Toxoplasma and anti-Toxocara antibodies in the sera of the dog trainers. A specific segment of the SAG2 and ITS genes were amplified via nested-PCR in order to molecularly detect T. gondii in human blood samples and Toxocara spp. in dog fecal samples.

RESULTS

Regarding serological findings, the prevalence of T. gondii in dog and human blood samples was 4% (2/50) and 10% (5/50), respectively. According to reports, the seroprevalence of Toxocara spp. in human blood samples was 6% (3/50). No statistically significant association was found between the prevalence of the examined parasites and variables (age, sex, and breed) in dogs, as well as the age variable in military personnel. Molecular findings showed that out of the 50 dog fecal samples and 50 human blood samples, there was no presence of Toxocara spp. and T. gondii, respectively.

CONCLUSION

Understanding the prevalence of parasitic infections helps public health officials assess the risk to human and animal populations. This information can guide the development of prevention and control measures to reduce the spread of these infections. Overall, the prevalence of parasitic infections, particularly T. gondii and Toxocara spp., in police dogs and their trainers remains uncertain and necessitates further in-depth research.

Molecular Determination of Toxocara spp. Eggs Isolated from Public Parks and Playgrounds in Zahedan, Southeast Iran

Background

Human toxocariasis (HT) is a zoonotic disease with a global expansion. Contaminated soil with Toxocara spp. eggs is the main source of human infection, which may lead to severe complications depending on the organs invaded by migrating larvae.

Aim

This study is aimed at eliciting the prevalence of Toxocara spp. eggs in public parks in Zahedan, southeast Iran, and providing new insight into the soil contamination rate in this area using microscopic and molecular methods.

Methods

Based on five municipal districts, 240 soil samples were collected from public parks and playgrounds in Zahedan. The modified Sheather's flotation technique was employed to isolate Toxocara spp. eggs from the soil, followed by microscopic assessment and molecular evaluation of internal transcribed spacer 1 and 2 ribosomal deoxyribonucleic acid (ITS1 and 2 rDNA) using nested polymerase chain reaction (nested PCR) to identify the presence of Toxocara spp. eggs. The Sanger sequence was used to differentiate the Toxocara species. Subsequently, all the sequenced data were blasted and compared with other sequences available in the GenBank.

Results

Out of 240 soil samples collected, 7 (2.9%) samples were identified to contain Toxocara spp. eggs using Sheather's flotation and microscopic techniques. Meanwhile, 19 (7.9%) samples were positive using nested PCR. According to the Sanger sequencing analysis findings, all positive samples were contaminated with Toxocara cati.

Conclusion

As evidenced by the obtained results, only T. cati species were detected in public parks and playgrounds in Zahedan; therefore, control and prevention programs against this species should be considered in human and animal communities.

Understanding the research and practical needs required to control toxocariasis in Iran

Human toxocariasis (HT) is a widespread zoonotic infection globally, notably prevalent in tropical areas. Enhancing our understanding of toxocariasis can lead to increased attention towards the socioeconomic impact and control of this neglected zoonosis. We conducted a comprehensive review of all available articles and official documents on toxocariasis in Iran to identify research gaps and critical needs for its control. This review highlights that despite numerous studies exploring various aspects of toxocariasis in definitive and paratenic hosts, as well as humans and environmental contamination, significant data deficiencies and gaps persist across different regions in the country. These gaps involve investigating the worm burden and reinfection rates in definitive hosts, developing more sensitive methods to detect and differentiate of Toxocara species, and understanding the behavior of definitive host animals. Additionally, identifying potential paratenic hosts for HT and exploring the organ-specific affinity and survival duration of Toxocara larvae within these hosts are essential areas for exploration. It's also imperative to comprehend the sylvatic and domestic cycles of the parasite in paratenic hosts. Furthermore, assessing egg density in the environment, exploring potential new sources such as water, and identifying regions with optimal climatic conditions for the survival and development of Toxocara eggs are crucial for the formulation of effective prevention and control strategies. Identifying at-risk groups, developing early diagnosis techniques, employing imaging methods, and identifying long-term complications in humans are also crucial. Community health organizations should prioritize health education for the public and professionals. Furthermore, accurately estimating definitive host populations, monitoring and preventing their movements in public places, implementing regular deworming practices for pets and stray hosts, and recognizing the infection's significance as a health priority are critical. This comprehensive understanding advocates for a holistic "one health" approach to control of HT.

Parasites of Stray Cats in Iran: A Parasitological and Histopathological Study

Many zoonotic parasitic diseases, including Toxocara cati, may be spread by stray cat populations. This study aimed to determine the prevalence of parasites by performing parasitological and histopathological examinations on stray cats in Shiraz, Iran. A total of 106 stray cats from different geographical areas of Shiraz, southern Iran, were examined for the presence of parasites. The overall prevalence was found to be 83.02% (88/106), and eight parasites were found. The parasites included three genera of cestodes [Joyeuxiella echinorhynoides (52.83%), Taenia taeniaeformis (21.70%), and Dipylidium caninum (1.89%)], three nematodes [Physaloptera praeputialis (23.59%), Toxocara cati (15.09%), and Rictularia sp. (1.89%)], one protozoa [Isospora spp. (6.60%)], and one arthropod [Ctenocephalides felis (5.66%)]. The prevalence did not significantly differ between males and females. It did appear, nevertheless, that the age of cats may be regarded as a risk factor for these parasitic infections. Histopathological examination revealed some parasite-induced lesions in the intestine and stomach, including hyperemia, hemorrhage, mucosal destruction and inflammation. The lung tissues showed some histopathological lesions such as hemorrhage, edema, emphysema and mild inflammation, and dormant larvae were found in one tongue sample. The results of the present study showed that parasitic infections and, more importantly, T. cati are relatively prevalent in stray cats, and the people living in this area are at serious risk of this zoonotic disease. The cats in this region need to be monitored, and specific preventive measures should be developed by public health officials.

Genetic and population diversity of Toxocara cati (Schrank, 1788) Brumpt, 1927, on the basis of the internal transcribed spacer (ITS) region

The present investigation was aimed to study the sequence, phylogenetic and haplotype analyses of Toxocara cati based on the ITS region, along with the genetic diversity, demographic history and population-genetic structure. The maximum likelihood tree based on Kimura 2-parameter model was constructed using the complete ITS region of all the nucleotide sequences (n = 57) of Toxocara spp. and other related ascarid worms available in the GenBank™. It placed all the sequences of T. cati into four major clades designated as T. cati genotypes 1-4 (TcG1-G4). A total of 66 signature nucleotides were identified in the ITS region between genotypes. The median-joining haplotype network displayed a total of 24 haplotypes, with China exhibiting the highest number of haplotypes (h = 20) followed by India (h = 4), and Japan and Russia (h = 1). It indicated a clear distinction between all the four genotypes. The pairwise F_ST values between all the genotypes indicated huge genetic differentiation (> 0.25) between different T. cati genotypes. Moreover, the gene flow (Nm) between T. cati genotypes was very low. Results of AMOVA revealed higher genetic variation between genotypes (92.82%) as compared to the variation within genotypes (7.18%). The neutrality indices and mismatch distributions for the G1-G4 genotypes, Indian isolates and the overall dataset of T. cati indicated either a constant population size or a slight population increase. The geographical distribution of all the genotypes of T. cati is also reported. This is the first report of genotyping of T. cati on the basis of the ITS region.

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.

Brain food: rethinking food-borne toxocariasis

Human toxocariasis is a neglected tropical disease, which is actually global in distribution and has a significant impact on global public health. The infection can lead to several serious conditions in humans, including allergic, ophthalmic and neurological disorders such as epilepsy. It is caused by the common roundworm species Toxocara canis and Toxocara cati, with humans becoming accidentally infected via the ingestion of eggs or larvae. Toxocara eggs are deposited on the ground when infected dogs, cats and foxes defecate, with the eggs contaminating crops, grazing pastures, and subsequently food animals. However, transmission of Toxocara to humans via food consumption has received relatively little attention in the literature. To establish the risks that contaminated food poses to the public, a renewed research focus is required. This review discusses what is currently known about food-borne Toxocara transmission, highlighting the gaps in our understanding that require further attention, and outlining some potential preventative strategies which could be employed to safeguard consumer health.

Seroprevalence and associated risk factors of toxocariasis among nomads in Boyer-Ahmad County, southwest Iran

BACKGROUND

Human toxocariasis is caused by the larval stage of Toxocara canis and Toxocara cati. This cross-sectional study was conducted to evaluate the seroprevalence and the risk factors associated with Toxocara infection in nomads of Boyer-Ahmad County in the southwest of Iran.

METHODS

A total of 968 blood samples were collected from nomads. A structured questionnaire, containing sociodemographic data, was completed for each participant. Sera were evaluated for anti-Toxocara antibodies, using the T. canis excretory-secretory antigens prepared from the second stage larvae, in an ELISA system.

RESULTS

Among the 968 participants, 220 (22.7%) were males and 748 (77.3%) were females; the mean age was 40.71 y. Anti-Toxocara IgG antibodies were detected in 14 (1.4%) of the 968 nomads. The association between Toxocara infection and gender, age, contact with dogs, residential area and level of education were not statistically significant (p>0.05).

CONCLUSIONS

The findings of the study revealed a low prevalence rate of toxocariasis in nomadic communities in southwest Iran. Geographic location and climatic conditions as well as the lifestyle and sociodemographic features of the participants may contribute to the low prevalence rate of Toxocara infection.

Comparison of the Detection of Toxocara Spp. in the Soils of Public Parks of Ahvaz (Southwest of Iran) by PCR and Loop-Mediated Isothermal Amplification (LAMP)

INTRODUCTION

The infections caused by Toxocara spp. are considered as one of the most important zoonotic diseases in the world, especially in developing countries. Human toxocariasis, particularly in children, is acquired by playing in public parks. Hence, the aim of the current study was to detect Toxocara spp. in the soils of public parks of the city of Ahvaz, southwest of Iran, using the PCR and loop-mediated isothermal amplification (LAMP) methods.

METHODS

In this descriptive cross-sectional study, 260 soil samples were randomly collected from the different public parks of the city of Ahvaz. After performing zinc sulfate (ZnSO₄) flotation technique, the DNA samples were extracted from the isolated Toxocara spp. eggs. Lastly, the extracted DNA was used for PCR and LAMP-based molecular detection.

RESULTS

Out of 260 specimens, 57 (21.9%) samples were found positive for Toxocara spp., using the PCR method, out of that 38 (14.6%) samples were positive for T. canis and 19 (7.3%) samples were positive for T. cati. Also, out of 260 specimens, 81 (31.1%) cases were positive for Toxocara species, using the LAMP method, among them 51 (19.6%) samples were found positive for T. canis and 30 (11.5%) samples were positive for T. cati. Kappa (κ) coefficient between PCR and LAMP showed a strong agreement (0.766, P-value=0.002).

CONCLUSION

The obtained data showed a relatively high outbreak of Toxocara spp. in the public parks' soils of the city, using the PCR and LAMP methods. Since the parasite can cause human toxocariasis, particularly in children; thus, the health authorities of the city of Ahvaz and other similar cities, especially in developing countries, must pay more attention to the hygiene of the public parks' soils.

The Role of Nile Tilapia (Oreochromis niloticus) in the Life Cycle of Toxocara spp

The present study aimed to experimentally assess Nile tilapia as potential paratenic host of Toxocara spp. A total of 15 Nile tilapia (Oreochromis niloticus) were fed with 300 embryonated Toxocara canis eggs by oral gavage, while five others of the control group received distilled water. The fish were individually analyzed at 16, 24, 48, 72, and 240 h after inoculation. Water contamination was assessed, and tissue migration by liver, gastrointestinal tract (GIT), eyes, and central nervous system. A murine model was used as the paratenic host for egg infectivity assessment. Eggs and larvae were found in plastic tank water and fish GIT, ranging from 23 to 86% per fish. Eggs and larvae were recovered from the tank water (76.3%) and fish GIT (23.7%). The counting of eggs and larvae observed was negatively correlated with number of eggs and larvae in the water tank (rho = -0.698, p = 0.003). Shedding of embryonated eggs was first detected at 16 and up to 240 h, with significant egg and larvae yield decrease on water-shedding (p = 0.001) and in the GIT (p = 0.007). Although no T. canis larva was recovered in fish tissues, egg infectivity after fish GIT transit was experimentally confirmed by mice assessment. In conclusion, despite shedding viable embryonated eggs through the gastrointestinal tract, tilapias may not play a role as a suitable paratenic hosts for Toxocara spp., posing low risk of zoonotic transmission by fish meat consumption.

Molecular characterization of ascaridoid parasites from captive wild carnivores in China using ribosomal and mitochondrial sequences

BACKGROUND

Despite the public health importance of toxocariasis/toxascariasis, only a few species of these ascaridoid parasites from wild canine and feline carnivores have been studied at the molecular level so far. Poor understanding of diversity, host distribution and the potential (zoonotic) transmission of the ascaridoid species among wild animals negatively affects their surveillance and control in natural settings. In this study, we updated previous knowledge by profiling the genetic diversity and phylogenetic relationships of ascaridoid species among eleven wild canine and feline animals on the basis of a combined analysis of the ribosomal internal transcribed spacer region (ITS) gene and the partial mitochondrial cytochrome c oxidase subunit 2 (cox2) and NADH dehydrogenase subunit 1 (nad1) genes.

RESULTS

In total, three genetically distinct ascaridoid lineages were determined to be present among these wild carnivores sampled, including Toxocara canis in Alopex lagopus and Vulpes vulpes, Toxocara cati in Felis chaus, Prionailurus bengalensis and Catopuma temmincki and Toxascaris leonina in Canis lupus, Panthera tigris altaica, Panthera tigris amoyensis, Panthera tigris tigris, Panthera leo and Lynx lynx. Furthermore, it was evident that T. leonina lineage split into three well-supported subclades depending on their host species, i.e. wild felids, dogs and wolves and foxes, based on integrated genetic and phylogenetic evidence, supporting that a complex of T. leonina other than one species infecting these hosts.

CONCLUSIONS

These results provide new molecular insights into classification, phylogenetic relationships and epidemiological importance of ascaridoids from wild canids and felids and also highlight the complex of the taxonomy and genetics of Toxascaris in their wild and domestic carnivorous hosts.

Prevalence of Toxocara and Toxascaris infection among human and animals in Iran with meta-analysis approach

BACKGROUND

Toxocariasis is a worldwide zoonotic parasitic disease caused by species of Toxocara and Toxascaris, common in dogs and cats. Herein, a meta-analysis was contrived to assess the prevalence of Toxocara/Toxascaris in carnivore and human hosts in different regions of Iran from April 1969 to June 2019.

METHODS

The available online articles of English (PubMed, Science Direct, Scopus, and Ovid) and Persian (SID, Iran Medex, Magiran, and Iran Doc) databases and also the articles that presented in held parasitology congresses of Iran were involved.

RESULTS

The weighted prevalence of Toxocara/Toxascaris in dogs (Canis familiaris) and cats (Felis catus) was 24.2% (95% CI: 18.0-31.0%) and 32.6% (95% CI: 22.6-43.4%), respectively. Also, pooled prevalence in jackal (Canis aureus) and red fox (Vulpes vulpes) was 23.3% (95% CI: 7.7-43.2%) and 69.4% (95% CI: 60.3-77.8%), correspondingly. Weighted mean prevalence of human cases with overall 28 records was 9.3% (95% CI: 6.3-13.1%). The weighted prevalence of Toxocara canis, Toxocara cati, and Toxascaris leonina was represented as 13.8% (95% CI: 9.8-18.3%), 28.5% (95% CI: 20-37.7%) and 14.3% (95% CI: 8.1-22.0%), respectively.

CONCLUSION

Our meta-analysis results illustrate a considerable prevalence rate of Toxocara/Toxascaris, particularly in cats and dogs of northern parts of Iran. The presence of suitable animal hosts, optimum climate and close contact of humans and animals would have been the reason for higher seroprevalence rates of human cases in our region. Given the significance clinical outcomes of human Toxocara/Toxascaris, necessary measures should be taken.

Human toxocariasis - A look at a neglected disease through an epidemiological 'prism'

Toxocariasis, a disease caused by infection with larvae of Toxocara canis, T. cati and/or congeners, represents clinical syndromes in humans including visceral and ocular larva migrans, neurotoxocariasis and covert/common toxocariasis. It is reported to be one of the most widespread public health and economically important zoonotic parasitic infections that humans share with dogs, wild canids, including foxes, and possibly other mammals. Humans become infected by accidental ingestion of embryonated Toxocara eggs, or larvae from tissues from domestic or wild paratenic hosts. Most infections are asymptomatic, and human disease may go unnoticed, as clinical investigation is often not pursued and/or diagnostic testing not conducted. Sometimes toxocariasis can be associated with complications, such as allergic and/or neurological disorders, possibly including cognitive or developmental delays in children. There is no anti-toxocariasis vaccine, and chemotherapy in humans varies, depending on symptoms and location of larvae, and may include the administration of albendazole or mebendazole, together with anti-inflammatory corticosteroids. Some recent studies indicate that toxocariasis is having an increased, adverse impact on human health in some, particularly underprivileged, tropical and subtropical communities around the world. Although tens of millions of people, especially children, are expected to be exposed to, or infected with Toxocara species, there is limited precise epidemiological data or information on the relationship between seropositivity and disease (toxocariasis) on a global scale. To gain an improved insight into this area, the present article reviews salient clinical aspects of human toxocariasis and the epidemiology of this disease, with particular reference to seroprevalence, and discusses future research and approaches/measures to understand and prevent/control this socioeconomically important, yet neglected zoonosis.