Atypical Toxocara canis-Induced Hepatic Visceral Larva Migrans: Diagnostic Challenges and Literature Review

Toxocariasis, a zoonotic infection transmitted by Toxocara canis (from dogs) and Toxocara cati (from cats) larvae, poses rare but severe risks to humans. We present a case of hepatic visceral larva migrans (VLM) caused by Toxocara canis in a 21-year-old male with a history of close contact with a pet dog. Initial symptoms and imaging findings mimicked a pyogenic liver abscess. The initial laboratory investigations revealed neutrophilia and elevated levels of IgE. Despite broad-spectrum antibiotics, persistent fever prompted further investigation. Subsequent serological testing for Toxocara antibodies and histopathological analysis of liver tissue demonstrating eosinophil infiltrates and Charcot-Leyden crystals led to a confirmed diagnosis of a liver abscess caused by Toxocara canis. Serological testing for Toxocara antibodies and histopathological analysis of liver tissue confirmed a Toxocara canis-induced liver abscess. Albendazole treatment yielded significant clinical improvement. This case highlights the necessity of considering toxocariasis in liver abscess differentials, particularly in high-seroprevalence regions like Vietnam. Relying solely on serological tests may be insufficient, emphasizing the need for corroborative evidence, including invasive procedures like liver biopsy, for accurate hepatic toxocariasis diagnosis.

[Atypical ocular toxocariasis in a child: A case report]

INTRODUCTION

Ocular toxocariasis is a rare disease, predominantly affecting children and young adolescents, and usually presenting as unilateral posterior uveitis. We report the case of a child with toxocariasis associated with serous retinal detachment.

OBSERVATION

A 8-year-old child with no previous history of toxocariasis was referred for a 1-year decline in visual acuity, unimproved by optical correction, with vitreous condensation on examination, without central or peripheral granulomas, and serous retinal detachment on OCT. The diagnosis was made after extensive questioning, with evidence of contact with dogs and positive serology. Medical treatment combining corticosteroid therapy and antiparasitic therapy was initiated, and the clinical picture improved.

DISCUSSION

Ocular toxocariasis is a rare infection, unilateral in 90% of cases. Its clinical manifestation in children is pars planitis, posterior uveitis with a posterior pole chorioretinal focus associated with vitreoretinal traction and/or peripheral granuloma. In our case, the patient presented with vitreous condensation only, with OCT serous retinal detachment and no peripheral or central granulomas. Positive plasma serology or ocular samples confirmed the diagnosis.

CONCLUSION

Ocular toxocariasis should not be ruled out in the absence of a typical clinical picture, and seropositivity enables confirmation of the diagnosis when clinical suspicion arises.

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.

Causes of infectious pediatric uveitis: A review

Infectious pediatric uveitis is a rare disease that can cause severe ocular damage if not detected rapidly and treated properly. Additionally, early identification of an infection can protect the child from life-threatening systemic infection. Infectious uveitis can be congenital or acquired and may manifest as a primary ocular infection or as a reactivation. Nevertheless, publications on infectious paediatric uveitis are usually limited to a small number of patients or a case report. So far, most studies on uveitis in children have focused primarily on noninfectious uveitis, and a systematic study on infectious uveitis is lacking. In this review, we summarize the literature on infectious uveitis in pediatric populations and report on the epidemiology, pathophysiology, clinical signs, diagnostic tests, and treatment. We will describe the different possible pathogens causing uveitis in childhood by microbiological group (i.e. parasites, viruses, bacteria, and fungi). We aim to contribute to early diagnosis and management of infectious pediatric uveitis, which in turn might improve not only visual outcome, but also the general health outcome.

Coinfection of Ocular Toxoplasmosis and Ocular Toxocariasis in the Same Patient

PURPOSE

To report a rare case of a toxoplasma chorioretinitis in one eye and peripheral ocular toxocariasis granuloma in the fellow eye of the same patient.

MATERIALS AND METHODS

Retrospective case report.

RESULTS

A 44-year-old male presented with gradual loss of vision over the past weeks. The patient was diagnosed with ocular toxoplasma chorioretinitis recurrence in his right eye and an inactive peripheral granuloma of ocular toxocariasis was found in the left eye. The patient was a farmer who had been involved in animal husbandry throughout his life. The patient was treated with antibiotics for toxoplasma chorioretinitis and kept under follow-up for ocular toxocariasis.

CONCLUSION

Coinfections of zoonoses are related to socioeconomic environment and individual characteristics of the host. Ocular toxoplasmosis and ocular toxocariasis may present with different scenarios. To our knowledge, this is the first case of a coinfection of ocular toxoplasmosis and ocular toxocariasis in the same patient. A thorough ophthalmological examination and detailed anamnesis are important for diagnosis.

Migratory pattern of zoonotic Toxocara cati and T. canis in experimentally infected pigs

BACKGROUND

Over a billion people are infected with Toxocara canis or T. cati, the roundworms of dogs and cats. Historically, T. canis has been considered the main species responsible for human toxocarosis, but as serodiagnosis cannot discriminate between the two species, this remains unresolved. We used pigs as a relevant large animal model for human infection to assess the migratory pattern of T. cati and T. canis.

METHODS

Pigs were inoculated with T. cati or T. canis eggs or PBS (negative controls) and necropsied 14 or 31 days later. Different organs and tissues were examined for parasites and pathological changes.

RESULTS

Overall, the two parasite species had a similar migration pattern reaching multiple organs and tissues, including the mesenteric lymph nodes, liver, lungs, and diaphragm. We recovered larvae of both species in the brain, suggesting that T. cati also can cause neurological toxocarosis in humans. Both species induced systemic eosinophilia and histopathological changes in the lungs, livers, and mesenteric lymph nodes.

CONCLUSION

This study emphasises the importance of T. cati as a zoonotic agent and the need to develop diagnostic methods that can differentiate between sources of infection in humans.

Toxocara canis infection in multiple types of animals: ophthalmological and pathological observations

Human ocular toxocariasis (OT), caused by pet roundworm Toxocara canis (Nematoda Ascaridoidea), is a worldwide ocular parasitic infection that poses a severe threat to eyesight, especially in school-aged children. However, the infection process and pathological mechanism of Toxocara are difficult to study in the human body. This study was designed to explore long-term ocular manifestations in different rodents infected with Toxocara canis, uncovering the specific pathological mechanism and migration pathway of larvae after infection. The three types of experimental animals we selected were C57BL/6 mice, Mongolian gerbils and Brown Norway rats. Mice were randomly divided into five groups and infected orally with 1000, 2000, 4000, 8000 and 10,000 T. canis eggs; gerbils were randomly divided into four groups and infected orally with 1000, 2000, 4000 and 10,000 T. canis eggs; rats were randomly divided into three groups and infected orally with 2000, 6000 and 10,000 T. canis eggs. Their ocular changes were closely observed and recorded for at least 2 months. We also enucleated the eyeballs of some animals to perform pathological sectioning and hematoxylin-eosin staining. After 3 dpi (days post-infection), hemorrhagic lesions, mechanical injury of the retina and larval migration could be observed in some infected animals. The ocular infection and mortality rates tended to be stable at 7 dpi. Larval tissue, structure disorder and inflammation could be observed in the pathological sections. In conclusion, the mice infected with 2000 T. canis eggs and gerbils infected with 1000, 2000 and 4000 T. canis eggs showing obvious ocular lesions and lower mortality rates could provide a basis for long-term observation.

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.

Cerebro-Ocular Toxocariasis Revealed by Bilateral Cystoid Macular Edema

DESIGN

Case Report Case description: This report describes the case of a female patient diagnosed with oculo-cerebral toxocariasis manifesting initially in the form of isolated bilateral cystoid macular edema. Diagnosis was made by means of positive anterior chamber and lumbar puncture western blots. The unusual presentation, ancillary findings and treatment are discussed. The control of intraocular inflammation that was only partially responsive to steroids was eventually achieved with pegylated interferon alfa-2a.

CONCLUSION

Isolated macular edema is a rare presentation of ocular toxocariasis. Interferon alfa-2a may prove useful in case of insufficient control of inflammation.

Toxocara Canis Increases the Potential of Breast Cancer by Reducing the Expression of the P53 Protein

INTRODUCTION

Breast cancer is considered the most frequent type of cancer in women with high mortality worldwide, and most importantly, it is the second most common cancer. However, some breast cancer-related risk factors remain unknown. So, the current study was designed to evaluate the effect of Toxocara canis on the biomarkers correlated with proliferation, apoptosis, inflammation, and angiogenesis in 4T1 tumor-bearing mice infected with Toxocara canis for the first time.

METHODS

Mice were categorized into four groups: A) control, B) treated with 4T1+ Toxocara canis, C) treated with Toxocara canis, and D) treated with 4T1. The expression of Ki-67 and P53 was then evaluated by using the immunohistochemical technique. In addition, the levels of transforming growth factor-β, Interferon gamma-γ, Interleukin 10, tumor necrosis factor-α and vascular endothelial growth factor as well as anti- Toxocara canis IgG were determined using the enzyme-linked immunosorbent assay method.

RESULTS

The expression of Ki-67 was significantly increased in the 4T1+ Toxocara canis group than control and Toxocara canis groups (P < 0.001 and P < 0.001, respectively). Moreover, a significant decrease in P53 was found in the 4T1+ Toxocara canis group than in the control and Toxocara canis groups (P < 0.001 and P < 0.001, respectively). Also, the 4T1+ Toxocara canis group significantly reduced the expression of P53 more than 4T1 tumor-bearing mice (P = 0.005). In addition, the 4T1+ Toxocara canis group had an increasing tumor necrosis factor-α and vascular endothelial growth factor than controls (P = 0.004 and P = 0.002, respectively). Furthermore, a significant reduction in Interleukin 10 was found in the 4T1+ Toxocara canis group than in the control group (P = 0.004).

CONCLUSION

Our findings showed that Toxocara canis could probably increase the potential of breast cancer by reducing P53 in 4T1 tumor-bearing mice infected with Toxocara canis more than other groups.

Who Let the Dogs Out? Unmasking the Neglected: A Semi-Systematic Review on the Enduring Impact of Toxocariasis, a Prevalent Zoonotic Infection

Toxocariasis remains an important neglected parasitic infection representing one of the most common zoonotic infections caused by the parasite Toxocara canis or, less frequently, by Toxocara cati. The epidemiology of the disease is complex due to its transmission route by accidental ingestion of embryonated Toxocara eggs or larvae from tissues from domestic or wild paratenic hosts. Even though the World Health Organization and Centers for Disease Control classified toxocariasis amongst the top six parasitic infections of priority to public health, global epidemiological data regarding the relationship between seropositivity and toxocariasis is limited. Although the vast majority of the infected individuals remain asymptomatic or experience a mild disease, the infection is associated with important health and socioeconomic consequences, particularly in underprivileged, tropical, and subtropical areas. Toxocariasis is a disease with multiple clinical presentations, which are classified into five distinct forms: the classical visceral larva migrans, ocular toxocariasis, common toxocariasis, covert toxocariasis, and cerebral toxocariasis or neurotoxocariasis. Anthelmintic agents, for example, albendazole or mebendazole, are the recommended treatment, whereas a combination with topical or systemic corticosteroids for specific forms is suggested. Prevention strategies include educational programs, behavioral and hygienic changes, enhancement of the role of veterinarians, and anthelmintic regimens to control active infections.

Toxoplasma and Toxocara seropositivity in juvenile idiopathic arthritis and its relation to disease activity and type of therapies

Juvenile idiopathic arthritis (JIA) is the most frequently encountered autoimmune rheumatic disease in children. To our knowledge, this is the first study aimed to estimate the frequency of Toxoplasma gondii (T. gondii) and Toxocara seropositivity in JIA and assess its relation to the disease activity, IL-10 levels, and type of the received therapies. This study was conducted on 43 JIA patients and 50 cases as a control group. All participants were evaluated by disease activity score (JADAS-27), and the presence of specific IgG and IgM antibodies against T. gondii and IgG against Toxocara species using an enzyme-linked immunosorbent assay. IL-10 serum levels were measured using an ELISA kit. The results show that JIA patients have significantly higher seropositivity for anti-T. gondii IgG compared to control subjects (p = 0.02) and a non-significant difference for Toxocara seropositivity (p = 0.41). All participants were negative for IgM anti-Toxoplasma gondii. Demographic parameters did not significantly affect these seroprevalence frequencies (p > 0.05). IL-10 was significantly higher among JIA patients compared to controls (p = 0.007) and seropositive anti-T. gondii JIA exhibited significantly higher IL-10 levels compared to seronegative ones (p = 0.03). Seropositive anti-T. gondii IgG JIA patients had a significantly higher disease activity score (JADAS-27) than seronegative anti-T. gondii IgG cases (p = 0.02). There was a significant positive correlation between anti-T. gondii IgG and JADAS-27 score (p = 0.009). A significant association was detected between T. gondii infection and DMARDs including the biological therapies (p < 0.05). Overall, this study supports a possible association between T. gondii infection and JIA, IL-10, disease activity score, and DMARDs therapies. It is possible that IL-10 plays a role in the development of JIA and contributes to persistent asymptomatic infection with T. gondii in JIA patients. As a result, a recommendation for screening tests for T. gondii infection among JIA patients is crucial before and during commencing DMARDs therapies and closely monitoring early signs of infection.

Toxocara canis seropositivity in different exposure groups in the Khyber Pakhtunkhwa province of Northwest Pakistan

Human toxocariasis is a highly prevalent zoonosis worldwide but is underreported in most countries. This study was conducted to evaluate Toxocara canis seropositivity in different exposure sub-groups located in the Mardan, Swabi, and Nowshera districts of the Khyber Pakhtunkhwa province of Northwest Pakistan. A total of 400 blood samples were collected from males 15 years of age and older with no animals, with livestock, with dogs and/or cats living in the house, and from butchers and veterinarians or para-veterinarians. Serum was tested using a commercial ELISA kit for detection of IgG antibodies against T. canis. Proportion seropositive was presented for each group and differences between groups were evaluated using the chi-square or Fisher's exact test as appropriate. Possible risk factors obtained through administration of a questionnaire were also evaluated for each sub-population. Overall T. canis seroprevalence was 14.2%, with a significant difference found between the seroprevalence of individuals with no animals (5.0%; 5/100), individuals with dogs and/or cats living in the household (8.0%; 8/100), individuals with livestock (18.0%; 18/100), veterinarians or para-veterinarians (24.0%; 12/50), and butchers (28.0%; 14/50) (p < 0.001). Significant differences in seropositivity by income bracket, education level, and working in the fields were found for some sub-groups. Study findings demonstrate that certain sub-populations, in Northwest Pakistan, may be at greater risk of T. canis infection. Development and implementation of targeted preventive strategies may, therefore, be needed.

A case report of spinal toxocariasis with extensive tumor-like involvement

BACKGROUND

Toxocariasis is a common parasitic infection worldwide. Although it can present as several clinical syndromes, neurological manifestation is rare. Only a few reports are available on spinal cord involvement of toxocariasis. We report a case that presented with gait disturbance due to progressive lower limb spasticity. The patient had had visceral toxocariasis infection 8 years before. A spine magnetic resonance image (MRI) showed syringomyelia along the entire thoracic cord with small nodular enhancing lesions in the mid-portion of the syrinx, which led to the suspicion of ependymoma. Surgical mass removal was performed. However, histopathological examination of the mass did not show any malignant cells; instead, there were numerous axonal retraction balls with an eosinophilic granular body-like appearance. The serum antibody titer against toxocariasis was borderline high. Taken together, these observations led to a diagnosis of Toxocara infection, and the patient was treated with albendazole.

CONCLUSION

To the best of our knowledge, this is the first case report of tumor-like spinal toxocariasis involving extensive lesions. A solid enhancing mass with accompanied syrinx and hemorrhage might be a Toxocara infection. It can easily be diagnosed with serologic tests and simply be treated with oral albendazole if suspected.

Potential roles of Toxocara canis larval excretory secretory molecules in immunomodulation and immune evasion

Toxocara canis larvae invade various tissues of different vertebrate species without developing into adults in paratenic host. The long-term survival of the larvae despite exposure to the well-armed immune response is a notable achievement. The larvae modulate the immune response to help the survival of both the host and the larvae. They skew the immune response to type 2/regulatory phenotype. The outstanding ability of the larvae to modulate the host immune response and to evade the immune arms is attributed to the secretion of Toxocara excretory-secretory products (TESPs). TESPs are complex mixture of differing molecules. The present review deals with the molecular composition of the TESPs, their interaction with the host molecules, their effect on the innate immune response, the receptor recognition, the downstream signals the adaptive immunity and the repair of tissues. This review also addresses the role of TESPs molecules in the immune evasion strategy and the potential effect of the induced immunomodulation in some diseases. Identification of parasite components that influence the nematode-host interactions could enhance understanding the molecular basis of nematode pathogenicity. Furthermore, the identification of helminths molecules with immunomodulatory potential could be used in immunotherapies for some diseases.

Retrospective Survey of Dog and Cat Endoparasites in Ireland: Antigen Detection

Endoparasites of dogs and cats, play an important role in both veterinary medicine and public health. Untreated and stray dogs and cats, in particular, play an important role in contaminating the environment with important zoonotic parasites. Thus, the aim of this study was to estimate the prevalence of intestinal parasites in stray dogs and cats using highly sensitive and specific copro-antigen tests. Archive faecal samples from previous surveys conducted between 2016−2019 from dogs (n = 789) and cats (n = 241) were included in this study. The IDEXX Fecal Dx™ antigen panel was used for the detection of Toxocara, hookworms, Trichuris and the SNAP™ Giardia antigen assay was used for the detection of Giardia infection. Giardia duodenalis was the most common parasite (26%, n = 205) detected in the dogs, followed by ascarids (17.6%, n = 139) and hookworms (5.3%, n = 42). Trichuris vulpis was only detected in 1 dog. Ascarids (23.2%, n = 56) was the most common parasite detected in the cats, followed by Giardia (12.9%, n = 31) and hookworms (n = 7, 2.9%). No whipworms were detected in cats. Overall, there was little difference in the positivity between sexes in both dogs and cats. However, in terms of age, adolescent dogs (<3 years) and kittens (<1 year) had the highest parasite prevalence overall, with G. duodenalis and ascarids being the most prevalent. This study shows a high prevalence of parasite infection in untreated and stray dogs and cats in the greater Dublin area in Ireland. Since they live in synanthropic conditions and can roam over vast distances they can contaminate public areas and pose a risk to both humans and owned pets that utilise these spaces. It is therefore important to raise public awareness and increase the knowledge on zoonotic parasites.

Recurrent vitreous opacity caused by intraocular Toxocara larva: a case report and literature review

BACKGROUND

Toxocara larva entity has seldom been reported on the surface of the retina. We report on an unusual case of recurrent vitreous opacity caused by intraocular Toxocara larva after vitrectomy.

CASE PRESENTATION

A 34-year-old male was referred to our clinic with a 6-month history of decreased visual acuity in the right eye characterized as red, painless, and progressive. Optos fundus photograph showed optic disc elevation with granuloma, and proliferative membrane starting from the optic disc and running towards the superior temporal retina due to the movement of a Toxocara larva, which was covered by the proliferative membrane in the superior temporal retina. Since it adhered closely to the retina, the lesion in the superior temporal retina was not removed to avoid induction of an iatrogenic retinal break and the larva was not found during the first diagnostic pars plana vitrectomy. Intraocular Anti-Toxocara IgG was 45.53U (< 3, enzyme-linked immunosorbent assay (ELISA)), and the Goldmann-Witmer coefficient was 8.55, confirming the diagnosis of ocular toxocariasis. After this operation, visual acuity improved to 20/200. However, vitreous opacity worsened again, and the proliferative membrane expanded around the Toxocara larva three weeks after the operation. Toxocara larva was found and removed in the superior temporal region during the second operation. His visual acuity improved to 20/100, vitreous opacity disappeared, and the retina was stable two months after the second operation.

CONCLUSION

It is advisable to remove suspected Toxocara larva to prevent the reoccurrence of ocular toxocariasis.

Seroprevalence of Toxocariasis Among Hypereosinophilic Children: A Single Center Study, Tehran, Iran

Background: Toxocariasis is a parasitic disease causing hypereosinophilia. This study aimed to investigate the serological prevalence of toxocariasis among hypereosinophilic children in Children’s Medical Center, Tehran, Iran, as well as to explore its relationship with epidemiological variables and some blood indices. Methods: This descriptive cross-sectional study was performed in 2020 on children referred to referral children hospital for routine tests. A total of 282 children diagnosed with hypereosinophilia were selected and included in the study, and then, their serum was collected. After obtaining informed consent from their parents, the parents were asked to fill out a questionnaire. The serological ELISA test was used to assess the anti-Toxocara IgG antibody. Data were analyzed using SPSS software 18. Results: Out of 282 hypereosinophilic children, 17 (6%) had serological results positive for anti-Toxocara antibody. The mean age of children with toxocariasis was higher than that of children without toxocariasis (P = 0.312). Furthermore, ESR and CRP variables were significantly higher in infected children than those in non-infected children (P < 0.05). Conclusions: The results of the present study confirmed the relationship between toxocariasis and hypereosinophilia. Since the symptoms of toxocariasis are non-specific and may go undiagnosed, it was found necessary to examine toxocariasis in cases of hypereosinophilic individuals.

Toxocara canis infection worsens the course of experimental autoimmune encephalomyelitis in mice

Toxocara canis, a gastrointestinal parasite of canids, is also highly prevalent in many paratenic hosts, such as mice and humans. As with many other helminths, the infection is associated with immunomodulatory effects, which could affect other inflammatory conditions including autoimmune and allergic diseases. Here, we investigated the effect of T. canis infection on the course of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Mice infected with 2 doses of 100 T. canis L3 larvae 5 weeks prior to EAE induction (the Tc+EAE group) showed higher EAE clinical scores and greater weight loss compared to the non-infected group with induced EAE (the EAE group). Elevated concentrations of all measured serum cytokines (IL-1α, IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ and TNF-α) were observed in the Tc+EAE group compared to the EAE group. In the CNS, the similar number of regulatory T cells (Tregs; CD4+FoxP3+Helios+) but their decreased proportion from total CD4+ cells was found in the Tc+EAE group compared to the EAE group. This could indicate that the group Tc+EAE harboured significantly more CD4+ T cells of non-Treg phenotype within the affected CNS. Altogether, our results demonstrate that infection of mice with T. canis worsens the course of subsequently induced EAE. Further studies are, therefore, urgently needed to reveal the underlying pathological mechanisms and to investigate possible risks for the human population, in which exposure to T. canis is frequent.

Evaluation of new Toxocara canis chimeric antigens as an alternative to conventional TES-Ag for anti-Toxocara antibodies detection

Human toxocariasis is one of the neglected helminthiases and it is caused by the zoonotic roundworm species Toxocara canis and Toxocara cati. Diagnosis of human toxocariasis is based on the combination of clinical, parasitological, and epidemiological criteria, as well as serology tests that detect anti-Toxocara antibodies. Notwithstanding, due to the absence of pathognomonic symptoms and signs of the disease, serology is the key evidence to support a conclusive diagnosis. TES-ELISA is the most widely used serological test for diagnosis. However, cross-reaction of TES antigens with antibodies produced to other helminth antigens is a major drawback for its application in countries with high parasitic prevalence. T. canis recombinant antigens have been described as an alternative to native TES for diagnosis. Nevertheless, the selection of antigenic proteins is a complex process that requires validation. In this paper, we developed an eGFP carrier-based system to express and purify blocks of recombinant polypeptides of T. canis antigenic proteins. Intense cross-reaction polypeptides were detected by Immunoblot and avoided to finally produce a chimeric prototype protein. Additionally, a control chimeric protein that harbors the complete tested proteins was produced. Purified chimeric antigens were tested in ELISA and Immunoblot assays with 310 sera samples of negative and positive control individuals. Our results showed that chimeric rCHITC0 and rCHITC1 antigens (with sensitivities of 62% 58%, 38% and 16% in IB-rCHITC0, ELISA-rCHITC0, ELISA-rCHITC1 and IB-rCHITC1 respectively for OLMS) can perform better in terms of specificity (being 91%, 89%, 87% and 76% for ELISA-rCHITC1, IB-rCHITC1, ELISA-rCHITC0 and IB-rCHITC0 respectively for OLMS) than T. canis TES-ELISA (with 61% specificity), giving a higher signal with serum samples of infected individuals as well the possibility to discriminate false positive cases with other parasitic infections. Our data suggest that T. canis chimeric proteins, represent candidate antigens for phase II studies.

Allergic asthma manifestations in human and seropositivity to Toxocara, a soil-transmitted helminth of carnivores: A case-control study and scoping review of the literature

Asthma is a common respiratory disease affecting humans. Helminth parasites, including Toxocara species, have been implicated as predisposing factors of asthma. However, various studies present different findings on asthma-Toxocara association. Herein, we investigated the association of asthma manifestations with Toxocara seropositivity in a case-control setting on 248 participants (147 women and 101 men), with 124 healthy individuals as the control group and 124 patients known to have asthma based on the medical records of asthma clinics of Kerman University of Medical Sciences. Consequently, we presented a scoping review of all previous studies carried out on this topic, summarizing current findings and existing knowledge on this issue. Of 248 participants, 31 (12.5%) were Toxocara-seropositive, of which 19 (15.3%) were in the patient group and 12 (9.7%) in the control group. A significant relationship was found between asthma severity and age in Toxocara-seropositive individuals (P < 0.04). We found no significant relationship between asthma and Toxocara seropositivity. We identified 7,724 related records in three major scientific databases, NCBI PubMed, Scopus, and Google Scholar. The review of the literature showed that there are 80 published articles on asthma-Toxocara relationship with contradictory findings. More than half of the studies were performed in only four countries, namely, Brazil, the Netherlands, the United States, and Iran. The study population in 70% of the studies were children, and few studies investigated asthma-Toxocara association in adults. The most common study designs for investigating the association of asthma and Toxocara seropositivity were cross-sectional (35.0%), case-control (27.5%), and animal experimental (12.5%) studies. This study found no significant relationship between asthma manifestations and toxocariasis in a case-control setting. However, a scoping review of the current literature suggests that further experimental and field longitudinal cohort studies are required to elucidate the nature of asthma-Toxocara interaction in humans.

In vitro anti-gastrointestinal cancer activity of Toxocara canis-derived peptide: Analyzing the expression level of factors related to cell proliferation and tumor growth

Background: Recently, a hypothesis about the negative relationship between cancers and parasites has been proposed and investigated; some parasitic worms and their products can affect the cancer cell proliferation. Due to the potential anti-cancer effect of helminthic parasites, in the present study, the excretory–secretory protein of Toxocara canis (T. canis) parasite was used to evaluate the possible anti-cancer properties and their effect on gastrointestinal and liver cancer cell proliferation-related genes in laboratory conditions.

Methods and materials: The selected synthesized peptide fraction from the T. canis excretory–secretory Troponin protein peptide (ES TPP) was exposed at 32, 64, 128, and 256 μg/ml concentrations to three gastrointestinal cancer cell lines AGS, HT-29, and Caco 2, as well as HDF cells as normal cell lines. We used the MTT assay to evaluate cellular changes and cell viability (CV). Variations in gene (Bcl-2, APAF1, ZEB1, VEGF, cyclin-D1, and caspase-3) expression were analyzed by real-time RT-PCR.

Results: After 24 h of exposure to pept1ides and cell lines, a decrease in CV was observed at a concentration of 64 μg/ml and compared to the control group. Then, after 48 h, a significant decrease in the CV of Caco 2 cells was observed at a concentration of 32 μg/ml; in the other cancer cell lines, concentrations above 32 μg/ml were effective. The peptide was able to significantly alter the expression of the studied genes at a concentration of 100 μg/ml.

Conclusion: Although the studied peptide at high concentrations could have a statistically significant effect on cancer cells, it is still far from the standard drug and can be optimized and promising in future studies.

The role of helminths in the development of non-communicable diseases

Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.

Prevalence and Molecular Characterization of Toxoplasma gondii and Toxocara cati Among Stray and Household Cats and Cat Owners in Tehran, Iran

Toxoplasma gondii and Toxocara spp. are the most critical parasites common between humans and cats. The close association of cats with humans in urban areas persuaded us to investigate the prevalence of these parasites in stray and household cats and their possible role in the owners' infection. Herein, 132 and 33 fecal samples of stray and household cats, respectively, and 33 blood samples of their owners were collected in Tehran, Iran. The prevalence of T. gondii was determined by targeting the B1 gene in the feces of stray and household cats and the blood of cat owners. Furthermore, genotypes of T. gondii were identified based on the multilocus genotyping of BTUB, GRA6, SAG3, and APICO loci. Toxocara spp. were detected by targeting the second internal transcribed spacer (ITS-2) of the ribosomal DNA of these parasites in the cats' feces and the humans' blood. Also, Toxocara IgG was assessed in the human serum samples. The B1 gene amplification showed that 15.2% of stray cats, 18.2% of household cats, and 51.5% of cat owners were infected with T. gondii. The multilocus sequence analysis revealed the predominance of genotype I of T. gondii in stray cats and genotype II of T. gondii in household cats and cat owners. The amplifying of ITS-2 revealed a high prevalence of T. cati infection (47.0%) in stray cats, whereas no infection was found in the feces of household cats or the serum of cat owners. Likewise, Toxocara IgG was not detected in the serum of humans. The lower prevalence of T. gondii in stray/household cats than in the cat owners indicates the limited impact of close contact with infected cats in human toxoplasmosis. However, the high prevalence of T. cati infection in stray cats can cause contamination of the environment by excreting eggs that may lead to infecting humans through soil or water. Therefore, public health education in urban management planning is necessary for routine urban cat deworming programs and for training the healthcare workers to prevent, control, and treat these infections.

Seroprevalence of anti-Toxocara canis antibodies and associated risk factors among dog owners in the rural community of Nakhon Si Thammarat province, southern Thailand

Background

Human toxocariasis is a zoonotic parasitic disease caused by the Toxocara canis and T. cati nematodes larvae. Dog owners are at a higher risk of acquiring T. canis infection, and there is no available evidence regarding the seroprevalence of T. canis infection among dog owners in Thailand. Therefore, this study aimed to investigate the seroprevalence of T. canis infection and associated risk factors among dog owners in rural areas of Thailand.

Methods

A total of 132 dog owners, including 25 men and 107 women, were recruited for this study. Serum anti-T. canis IgG antibodies were detected using a commercial enzyme-linked immunosorbent assay (ELISA) kit, and information on risk factors was collected using a questionnaire. In addition, hematological parameters were analyzed by the auto hematology analyzer. Risk variables associated with T. canis infection were investigated using univariate and multivariate logistic regression models.

Results

The overall seroprevalence of T. canis was 76.5% (101/132). Men were more likely to be infected with T. canis than women. Univariate analysis revealed that dog owners who did not practice handwashing before meals (p = 0.005) or after contact with soil (p = 0.035) or dogs (p = 0.049) had a substantially higher risk of acquiring T. canis infection. After adjusting for confounders, not practicing handwashing before meals remained a significant risk factor for T. canis infection (p = 0.038). The mean number of eosinophils was significantly higher in the seropositive group than in the seronegative group.

Conclusions

This is the first serological report of T. canis infection among dog owners reflecting the high rate of T. canis seropositivity in rural areas of southern Thailand. This study also provides group-specific data concerning modifiable risk behaviors for more effective T. canis infection control and prevention strategies in Thailand.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41182-022-00425-4.

Cytokine Profile in Aqueous Humor of Patients With Ocular Toxocariasis

Purpose

Ocular toxocariasis (OT) is a vision-threatening disease with a largely unknown intraocular pathogenesis. Herein, we determined the cytokine expression profile in aqueous humor (AH) of patients with OT.

Methods

This is a retrospective case-control study of cytokine levels in AH of patients with OT and uveitis and control subjects. Thirty samples from eyes with OT, 23 from eyes with non-OT uveitis, and 25 from eyes with age-related cataract were analyzed using a multiplexed magnetic bead immunoassay. Thirty-one cytokines were detected and classified into 5 categories: T-helper type 1 (Th1) -associated cytokines, Th2-associated cytokines, Th17 cytokine, proinflammatory mediators, and growth factors.

Results

In the 31 cytokines, 9 cytokines were undetectable, including IL-1a, IL-1b, IL-2, IL-3, IL-12p70, IL-17A, TGF-a, TNF-β, and IFN-g. From the 22 cytokines, 13 exhibited significantly increased expression in the OT group than in the control group, including TNF-a, IFN-a2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, sCD40L, PDGF-AA, PDGF-AB/BB, FLT3l, and EGF. There were 5 cytokines exhibited significantly increased expression in the OT group than in non-OT group, including IL-5, IL-9, IL-10, IL-13, and PDGF-AA. There was no significantly decreased expression in any cytokines in the OT group when compared with control or non-OT groups. To the 5 cytokines that showed significant difference in OT group alone, IL-10 and IL-13 exhibited more than 13-fold increase, and IL-5 showed the most obvious as 27-fold increase in OT patients, when compared with that in control group.

Conclusion

The cytokine profile expression in aqueous humor from patients with ocular toxocariasis was investigated, and our findings suggest that Th1 and Th17 cytokine responses are not enhanced, whereas the cytokine status was polarized toward a Th2 response. Our findings also suggest the involvement of IL-5, IL-10, and IL-13 in the immunopathogenesis of ocular toxocariasis.

Detection of Toxocara cati Larvae in a Common Buzzard (Buteo buteo) and in a Red Kite (Milvus milvus) in Basilicata Region, Italy

Toxocara cati is a common parasite of wild and domestic felines,and presents a cosmopolitan distribution. Adult parasites localize in the gut of the definitive host giving rise to the infection, which usually runs asymptomatic. These worms produce eggs that are excreted with feces into the environment, where they become a source of infection for paratenic hosts, such as mammals, birds, and invertebrates. In this brief communication, we report the detection of T. cati larvae in a common buzzard (Buteo buteo) and a red kite (Milvus milvus), in the Basilicata Region of Italy. This result may be important to define new pathways of spread and survival of T. cati in the wild.

Hypopyon and White Cataract Due to an Intraocular Helminth

We describe a case of a 29-year-old man with a history of intravenous drug use and vague history of eye trauma who presented with a hypopyon and white cataract in the right eye. He underwent pars plana vitrectomy and lensectomy; his anterior chamber aspirate revealed a single helminth on calcofluor stain. We suspect that his helminth infection may be secondary to unsanitary eating and drinking practices. As overall hygiene and dietary habits have improved during the years, parasitic helminth infections are relatively rare in nonendemic areas, especially in the nonpediatric population. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:168-171.].

Toxocara canis- and Toxocara cati-Induced Neurotoxocarosis Is Associated with Comprehensive Brain Transcriptomic Alterations

Toxocara canis and Toxocara cati are globally occurring zoonotic roundworms of dogs and cats. Migration and persistence of Toxocara larvae in the central nervous system of paratenic hosts including humans may cause clinical signs of neurotoxocarosis (NT). As pathomechanisms of NT and host responses against Toxocara larvae are mostly unknown, whole-genome microarray transcription analysis was performed in cerebra and cerebella of experimentally infected C57Bl/6J mice as paratenic host model at days 14, 28, 70, 98, and 120 post-infection. Neuroinvasion of T. cati evoked 220 cerebral and 215 cerebellar differentially transcribed genes (DTGs), but no particular PANTHER (Protein ANalysis THrough Evolutionary Relationships) pathway was affected. In T. canis-infected mice, 1039 cerebral and 2073 cerebellar DTGs were identified. Statistically significant dysregulations occurred in various pathways, including cholesterol biosynthesis, apoptosis signaling, and the Slit/Robo mediated axon guidance as well as different pathways associated with the immune and defense response. Observed dysregulations of the cholesterol biosynthesis, as well as the Alzheimer disease-amyloid secretase pathway in conjunction with previous histopathological neurodegenerative findings, may promote the discussion of T. canis as a causative agent for dementia and/or Alzheimer’s disease. Furthermore, results contribute to a deeper understanding of the largely unknown pathogenesis and host-parasite interactions during NT, and may provide the basis for prospective investigations evaluating pathogenic mechanisms or designing novel diagnostic and therapeutic approaches.

Two trichinellosis outbreaks in Serbia – challenging diagnosis due to a potential co-infection with Toxocara spp

In Serbia, in most cases, small family outbreaks of trichinellosis occur due to the consumption of untested infected meat from domestic pigs that are raised and slaughtered in the backyards of small individual farms. The aim of this study is to present data regarding 24 patients involved in two outbreaks that occurred in two neighbouring districts in Serbia during a closely related period of time in August 2014. The source of infection in the first outbreak was undercooked pork, while raw pork sausages caused the second outbreak. Meat samples and sausages were Trichinella spp. positive by artificial digestion. With the aim to obtain a second opinion and validate the serological findings discovered at the Public Health Institute Nis, all samples were sent to the National Reference Laboratory for Trichinellosis, INEP. Serodiagnosis showed that 21 persons were positive (87.5%) and three (12.5%) were negative for anti-Trichinella antibodies, while 15 patients fulfilled the trichinellosis case definition. Western blot analysis (using an epitope unique for the muscle larvae stage of the Trichinella genus) confirmed the diagnosis of trichinellosis in five patients. Six patients also had specific antibodies against Toxocara canis (T. canis). Due to the fact that in endemic foci in Serbia there is the presence of Trichinella spiralis and T. canis and that these two infections could be asymptomatic, we consider that trichinellosis cases were irrefutably proven. The dilemma about the existence of co-infection with T. canis remained open due to the lack of clinical findings.

Acute and chronic immunomodulatory response mechanisms against Toxocara canis larvae infection in mice

Abstract The objective of this work was to evaluate the early and late immunological modulation of an experimental infection of T. canis larvae in mice. Mice were infected with 100 infective larvae and euthanized at different period: 24, 48 hours post infection (HPI), 15- and 30 days post infection (DPI). The humoral response was evaluated by indirect ELISA. Quantitative RT–PCR (qPCR) was used to quantify the mRNA transcription of cytokines IL4, IL10, IL12 and Ym1 in the early and late infection periods. Infection with T. canis was able to generate specific total IgG at 15- and 30- DPI. Analyzing the IgG isotype revealed a significant differentiation for IgG1 compared with IgG2a, IgG2b and IgG3, characterizing a Th-2 response. Evaluating the gene transcription at the early phase of infection, higher transcription levels of IL10, IL4 and Ym1 and a downregulation of IL12 were observed. By the late phase, increased transcription levels of IL4, Ym1 and IL12 were observed, and downregulation of IL-10 transcription was observed. The data obtained suggest that during experimental infection with T. canis, the participation of the IL4, IL10, IL12 cytokines and Ym1 can play an important role in T. canis immunomodulation.

Detection of Toxocara cati Larvae from Ostrich and Wild Boar Meat Intended for Human Consumption

Toxocara cati is a common roundworm of cats and wild felids and, together with T. canis, it is the main causative agent of human toxocariasis. Humans may become infected by ingestion of embryonated eggs via contaminated soil, food, or water, or by ingestion of raw or undercooked meat of paratenic hosts that are infected by Toxocara larvae. In this study, we report the detection of T. cati larvae from meat samples of ostriches and wild boars. These samples were inspected by enzymatic digestion, as part of the trichinellosis surveillance. As ostrich meat is intended for “carpaccio” preparation, a traditional Italian raw meat preparation, there is the need to make the consumption of this meat safe. For this purpose, it is recommended to freeze the meat before preparation. Our findings confirmed that T. cati larvae can contaminate muscle tissues of paratenic hosts, increasing the risk of infection due to the consumption of raw or undercooked meat.

Frequency of Toxocara Antibodies in Patients Clinically Suspected to Ocular Toxocariasis, Northeast of Iran

Background:

Human toxocariasis is a neglected parasitic disease in most countries including Iran. Among different clinical forms of toxocariasis, ocular toxocariasis (OT) is an important disease resulting in severe vision loss. However, the prevalence and incidence of OT are currently unclear in Iran. This study aimed to determine the prevalence of ocular toxocariasis among patients with uveitis in the Northeast of Iran.

Methods:

From 2015 to 2017, 510 patients with uveitis referred to Khatam-al-Anbia, a tertiary eye hospital at Mashhad, Iran were examined for OT. Serum samples of the suspected patients were obtained and evaluated for IgG against Toxocara canis using ELISA test. Anti-Toxocara IgG positive serums were further investigated using confirmatory Western blotting (WB) analysis.

Results:

Twenty patients had pathologic changes and clinical presentations in the anterior and posterior segments of their eyes and they were clinically diagnosed ocular toxocariasis. Among the 20 patients, 2 (10%) patients showed IgG antibody against Toxocara canis on ELISA as well as on WB test. The calculated prevalence of ocular toxocariasis was about 0.4%.

Conclusion:

Ocular toxocariasis can be diagnosed both clinically and serologically in Mashhad, northeastern Iran. Although OT is a rare pathologic eye disease, it should be considered as one of the important cause of infectious posterior uveitis.

Toxocara Species Infection in Pet Dogs and Cats Ensured by Loop-Mediated Isothermal Amplification Assay

Background: Toxocariasis is a parasitic disease with global distribution. Many paratenic or transport hosts have been identified as the sources of infection, including vertebrates such as birds and humans. The definitive hosts of Toxocara are dogs and cats whose parasites live in their guts. Hence, the diagnosis of the disease in these animals is important. Objective: The present study was performed using the loop-mediated isothermal amplification (LAMP) method to diagnose toxocariasis. Materials and Methods: In the present study, 60 samples of pet feces were collected and subsequently evaluated by direct smear, formalin-ether, and LAMP. Results: Toxocara infection in dogs by microscopic and formal ether methods and LAMP method was 10% and 13.3%, respectively, while feline infection with this parasite was not observed either microscopically or molecularly. Conclusion: The present findings revealed that pet dogs can be considered as a source of infection for humans. Therefore, it is recommended that animal owners receive the necessary training to prevent the risks of transmitting zoonotic diseases.

Toxocara Seroprevalence and Risk Factor Analysis in Four Communities of the Wiwa, an Indigenous Tribe in Colombia

The life of the indigenous Wiwa tribe in northeast Colombia is characterized by lacking access to clean drinking water and sanitary installations. Furthermore, free-roaming domestic animals and use of yucca and/or manioc as a primary food source favor the transmission of soil-transmitted helminths, e.g., Toxocara&nbsp;canis and Toxocara&nbsp;cati, the roundworms of dogs and cats. Infection may result in the clinical picture of toxocarosis, one of the most common zoonotic helminthoses worldwide. To estimate the Toxocara seroprevalence in four different villages of the Wiwa community, serum samples from 483 inhabitants were analyzed for anti-Toxocara-antibodies. Overall, 79.3% (383/483) of analyzed samples were seropositive. Statistically significant differences were observed between the four villages, as well as age groups (adults > adolescents > children), while sex had no effect. The high seropositivity rate demonstrates the risk of zoonotic roundworm infections and potential clinical disease in vulnerable indigenous inhabitants.

Insights into geohelminth contamination in Bangladesh: feasibility of a modified diagnostic method and prevalence study

INTRODUCTION

The objectives of this study were to evaluate a modified method for isolating geohelminth eggs and to assess the geohelminth contamination in Bangladesh.

METHODS

The efficacy of the modified method was evaluated using naturally contaminated and experimentally seeded soil samples. In total, 240 samples were assessed from four different sites in three geographic contexts. A questionnaire survey with 50 professionals was conducted.

RESULTS

The modified method showed considerable efficacy in isolating parasitic eggs from naturally contaminated soil (54.0%) and experimentally seeded soils (63.0% for Toxocara eggs and 52.0% for Ascaris eggs). The modified method was described as convenient by the majority of participants. Overall prevalence was 52.5%, with several species of helminth observed, including Toxocara sp., Ascaridia galli/Heterakis gallinarum, Ascaris sp., hookworms/strongyles, Capillaria sp., Trichuris sp., and taeniids). The contamination rate was found to be higher around livestock farms (76.7%), followed by latrines (63.3%), households (41.6%), and schools (28.3%).

CONCLUSIONS

The modified method was shown to be feasible in terms of field applicability and egg recovery rate, and could be adopted in low-resource settings. A substantial prevalence of geohelminths was observed, with some of the species associated with zoonoses. These findings highlight the urgent need for widespread mapping of geohelminths to avoid spillovers to animals and humans.

Diagnosis of Ocular Toxocariasis by Serum and Aqueous Humor IgG ELISA

Purpose

Ocular toxocariasis (OT) is a worldwide ocular parasitic infection and is especially sight-threatening in children. Because of the clinical manifestation diversity, OT has frequently been misdiagnosed. The purpose of this study was to evaluate the diagnostic value of anti-toxocara immunoglobulin G (IgG) in intraocular fluid (IF) and serum in OT.

Methods

IF and serum were collected from patients with clinically diagnosed OT and non-OT uveitis. The level of anti-toxocara IgG was detected by enzyme-linked immunosorbent assay. The data were statistically analyzed in anti-toxocara IgG and the Goldmann–Witmer coefficient (GWC) between groups. The area under the receiver operating characteristic curve (AUC ROC) was performed to assess the diagnostic value of serum and IF anti-toxocara IgG and the GWC.

Results

A total of 290 participants, 128 (44.1%) with OT and 162 (55.9%) with non-OT uveitis, were included in this study. The default serum anti-toxocara IgG cutoff value of 11 U had 72.1% sensitivity and 95.5% specificity. With the optimized cutoff value of 8.2 U, the AUC was 0.886 (95% confidence interval [CI] = 0.830–0.929, P < 0.0001), sensitivity increased to 80.2%, and specificity was 94.0%. With an IF anti-toxocara IgG cutoff value of 1.8 U, the AUC was 0.934 (95% CI = 0.892–0.963, P < 0.0001), sensitivity was as high as 88.4%, and specificity was 96.4%.

Conclusions

Our study proposes novel diagnostic cutoff values of serum and IF anti-toxocara IgG for OT, which are 8.2 U and 1.8 U, respectively.

Translational Relevance

This study will improve the accuracy of diagnosis in patients with OT.

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.

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.

Serosurvey and associated risk factors of anti-Toxocara spp. antibodies in bovines from slaughterhouses of southeastern Brazil

BACKGROUND

Toxocariasis, caused by a nematode species of the genus Toxocara, has been described as one of the most prevalent zoonotic helminthiases worldwide. Human transmission may occur by ingesting Toxocara spp. larvae from raw or undercooked meat or organs; however, no comprehensive serosurvey study has been conducted to date investigating the role of cattle as paratenic hosts. The aim of the study reported here was to assess the prevalence of anti-Toxocara spp. antibodies and associated risk factors in bovines from two slaughterhouses located in Presidente Prudente, southeastern Brazil.

METHODS

Blood samples were collected and tested by indirect enzyme-linked immunosorbent assay (ELISA). Cattle farmers voluntarily responded to an epidemiologic questionnaire.

RESULTS

Overall, 213 of the 553 (38.5%) bovine samples were assessed as seropositive for anti-Toxocara spp. antibodies by indirect ELISA. Multivariate analysis revealed that the source of beef cattle and the presence of dogs or cats at the farm were associated with seropositivity. The use of feedlot systems was associated with lower likelihood of seropositivity.

CONCLUSIONS

These results indicate a high level of anti-Toxocara seropositivity in slaughterhouse cattle, with potentially contaminated meat posing an infection risk to humans. In addition, the presence of dogs and cats where the slaughtered beef cattle were raised was statistically associated with bovine seropositivity, probably due to the overlapping environment at the farm and the lack of pet deworming. The use of feedlot systems was a protective factor likely due to the absence of dog and cat contact, elevated feeding troughs that avoid contact with contaminated soil or grass, and younger age at slaughter of feedlot cattle. In summary, bovines may be used as environmental sentinels of Toxocara spp. contamination, and high seropositivity of slaughterhouse cattle may indicate a potential risk of human toxocariasis through the ingestion of raw or undercooked contaminated meat.

Molecular evaluation of Toxocara species in stray cats using loop-mediated isothermal amplification (lamp) technique as a rapid, sensitive and simple screening assay

Toxocara species are parasitic nematodes of dogs and cats with a worldwide distribution. The adult worm lives in the intestine, and horizontal transmission of the infection occurs through eating paratenic host or embryonated eggs. This study aimed to estimate the molecular prevalence of Toxocara species in stray cats using the loop-mediated isothermal amplification (LAMP) technique. A total of 95 stool samples were randomly collected from stray cats in Khorramabad city in western Iran. Microscopic examination was performed after the separation and extraction of supernatants. The LAMP reaction was performed using the internal transcribed spacer 2 (ITS2) gene primers of Toxocara species and the appropriate master mix. The overall prevalence of Toxocara spp. in stray cats was 20% (19/95, CI 95%: 0.2 ± 0.08) by parasitological and molecular assessments. The microscopic examination of stool samples revealed that 19 samples were positive for Toxocara. The same 19 positive samples were also positive by the LAMP technique. Interestingly, based on the results of the LAMP assay, out of 95 studied samples, 18 (18.94%; CI 95%: 0.19 ± 0.08) specimens were Toxocara canis, while only 1 (1.05%; CI 95%: 0.005 ± 0.01) sample was diagnosed as Toxocara cati. The relatively high prevalence of Toxocara species in the studied cats shows the role of this species in spreading the parasite and the role of the cats in transmitting this zoonotic parasite. Preventive measures including the control of stray cat's population by castration and protection of public gardens where children play are recommended. The easy, highly sensitive and specific LAMP method is proposed for the differential detection of Toxocara species in animals and humans.

Socioeconomic factors associated with infection by Toxoplasma gondii and Toxocara canis in children

The intense contact of children with domestic animals or environments contaminated with faeces of these animals, together with habits related to lack of hygiene, can facilitate infection by zoonoses. The study evaluated the seroprevalence and risk factors associated with toxoplasmosis and toxocariasis in schoolchildren in the city of Jataizinho, Paraná. Of the 412 children aged 4-15 years, 56.8% (234/412) presented antibodies reactive to Toxoplasma gondii, 42.5% (175/412) presented antibodies reactive to Toxocara canis, and 27.4% (113/412) were reactive for the two species. The analysis of risk factors showed that prevalence of toxoplasmosis and toxocariasis was associated with the level of education of the child's mother (less than eight years of schooling), age range (10-15 years) and the presence of cats in the residence. In addition, family income (up to a minimum wage), presence of a dog, the habit of playing in soil/sand and eosinophilia were associated with Toxocara canis infection. There was an association between the two zoonoses (p < .01), indicating the existence of coinfection. The results show high prevalence of these two important zoonoses, alerting to the need of implementing control measures in order to reduce the incidence and risks of sequelae in children.

Toxocara Awareness Among Medical Practitioners in Saudi Arabia

Human toxocariasis is a zoonotic infection with global and regional impacts. Worldwide it is underestimated and clinically overlooked. Medical practitioners are generally unaware of the extent of the resulting disease spectrum. The objective of the study was to assess knowledge and disease awareness among medical practitioners in Aseer, south-western Saudi Arabia. A questionnaire addressing knowledge about the parasite, its visceral larva migrans and the disease spectrum generated was used to interview participants. The study included 285 participants. In answer to the question what is toxocara, only 27%, answered correctly that it is a nematode, paediatricians being the majority. With regard to years of experience among participants, 56.8% of those who answered correctly had less than 5-year experience, as opposed to 35.4% for those with more than 10-year experience. The cumulative awareness about the disease manifestations and spectrum, i.e. those who knew, was less than 30% across specialties and years of experiences. Lack of awareness regarding Toxocara infection and the disease spectrum it can generate is evident. The consequence for such lack of knowledge within our practising medical community is simply unacceptable as it might translate into misdiagnosis and consequently misguided treatment.

Identification and Immunological Characterization of Somatic Proteins from Adults of Toxocara cati by Proteomics Technique

Background:

Toxocara cati is considered as one of the main etiological agents of toxocariasis with global and regional importance. As there is no information on proteomics of T. cati, herein, we reported the results obtained by proteomic analysis of somatic proteins extract, using a mass spectrometry (LC–MS/MS) approach.

Methods:

Somatic extract fractions were separated by two-dimensional SDS-PAGE and were electro blotted on to PVDF membranes for immunoblot analysis, then collected the immunogenic spots which response of antibodies of the paratenic hosts (mice) to the antigens (Mashhad, 2017), and analyzed by LC–MS/MS. The LC-MS/MS data were analyzed by Mascot database, Taxonomy Toxocara, and common contaminants, in Omics Center, Biotechnology Medical University of Graz (Austria, 2018).

Result:

The protein spots were isolated between 15–140 kDa ranges using 3–10 non-linear IPG strips and Brilliant Blue Coomassie. Ten proteins were characterized as immunogenic proteins, seven of them were identified and three of them were unknown proteins.

Conclusion:

This study provided additional information about the somatic antigens of T. cati, which can lead to the development of new strategies for novel immuno-modulators, drug targets, subunit vaccines and immunodiagnostic kits for toxocariasis.

The first two cases of neurotoxocariasis in Taiwan

Toxocariasis is a zoonosis disease with high sero-prevalence in Southeast Asian. Neurotoxocariasis has never been reported in Taiwan. Herein, we presented 2 cases of neurotoxocariasis. The first case is a 48-year-old man with febrile headache, rapid progressive cognitive problems and later thoracic myelitis. Meningeal enhancements on the corresponding sites were found on magnetic resonance imaging (MRI). Eosinophilic pleocytosis was present in peripheral blood and cerebrospinal fluid (CSF). A positive Toxocara canis larval excretory-secretory antigen (TcES)-based immunoblotting test for CSF confirmed the diagnosis. The second case is a 42-year-old woman of progressive headache with features of increased intracranial pressure. CSF analysis showed lymphocytic pleocytosis initially and eosinophilic pleocytosis later. Her brain MRI was normal. The diagnosis was confirmed by the presence of anti-TcES IgG in CSF. The two cases were soonly cured by mebendazole. Neurotoxocariasis presented a broad spectrum of neurological symptoms and the CSF profile can be non-eosinophilic pleocytosis. The prevalence of neurotoxocariasis may be seriously underestimated due to low awareness of physicians and lack of standard conventional diagnostic test in Taiwan. The two cases of neurotoxocariasis firstly reported in Taiwan will raise physician's awareness in recognizing this curable disease particularly in managing patients with aseptic meningitis or meningoencephalitis of undetermined pathogen.

Multimodality Image Analysis in a Cohort of Patients with Atypical Juvenile Ocular Toxocariasis

Purpose

To analysis the multimodal imaging of a group of patients diagnosed clinically with atypical juvenile ocular toxocariasis (OT).

Methods

In this case series study, we examined 9 young patients diagnosed with atypical OT. Routine ophthalmological examinations, fundus photography, optical-coherence tomography (OCT), fluorescein angiography (FFA), and B-mode ultrasound were performed. A questionnaire was used to record whether the patients were newly diagnosed and whether they had a history of exposure to a cat and dog. Aqueous humor and serum samples were taken for serological tests.

Results

In all the patients, yellow-and-white dot-shaped lesions and perivascular white sheath were seen in the fundus. Heterogeneous changes including hyper-reflection in the disrupted neuroretina, hyper-reflection in the outer retinal layer, high-reflection mass on the surface of the neuroretina accompanied with reflective attenuation, and high-reflection mass involving the entire neuroretina or high-reflection mass in the vitreous body were noticed in OCT images. On FFA, seven of these patients (77.8%) showed leakage of fluorescein in the small- and medium-branch veins of the retina, and a “bristle-like” change indicated increased permeability of the vessels. B-mode ultrasound showed proliferative membranes and proliferative bands (33.3%), as well as spotted opacity in the vitreous (66.7%). The antibodies to Toxocara canis in the aqueous humor and serum were positive, and the Goldmann–Witmer coefficient was significantly increased in 6 out of 7 patients.

Conclusions

Multimodality images are useful in the diagnosis of atypical juvenile OT, which could be easily overlooked and misdiagnosed.

Predators in northern Germany are reservoirs for parasites of One Health concern

Urbanisation and invasion of wildlife into urban areas as well as human leisure activities create diverse wildlife-domestic animal-human interfaces, increasing the risk of (zoonotic) parasite spillover from sylvatic to domestic and synanthropic cycles. This study investigated the endo- and ectoparasite fauna, emphasising on parasites of One Health Concern, of the most common predators in northern Germany between November 2013 and January 2016. Eighty red foxes (Vulpes vulpes), 18 stone martens (Martes foina) and nine raccoon dogs (Nyctereutes procyonoides) were available for the study. Overall, 79 (73.8%) of the examined predators (n=107) harboured at least one endoparasite. The most frequently detected endoparasites in red foxes were Toxocara canis (43.8% positive individuals), Capillaria spp. (36.3%), Alaria alata (25.0%), Echinococcus multilocularis (26.3%) and Uncinaria stenocephala (25.0%). Furthermore, Toxascaris leonina, Trichuris vulpis, Taenia ssp., Mesocestoides spp. and coccidian oocysts were observed. The endoparasite species richness in raccoon dogs was comparable to red foxes, while in stone martens, only Capillaria spp. were found. Muscle digestion for detection of Trichinella spp. and antigen testing for Giardia spp. did not show positive results. Ectoparasite analyses revealed infestations with ticks species of the genus Ixodes as well as Dermacentor reticulatus. Scabies mites were not present in digested skin samples, while Demodex spp. mites were observed by faecal flotation in one red fox. Furthermore, fleas (Archaeopsylla erinacei and Chaetopsylla globiceps) were observed in the fur of red foxes, while lice were not present in any predator species. However, infestation frequency with ectoparasites was with 19.2% generally low in available predator skins (n=99). Overall, the present study showed that predators in northern Germany serve as reservoirs for parasites of One Health concern, with four of the five most frequent endoparasites being zoonotic, highlighting the need of parasite surveillance in wildlife predators in order to implement measures avoiding spillovers to domestic animals and humans.

Role of cats in human toxocarosis

Toxocara cati, the feline ascarid, is ubiquitous in domestic cats globally and is increasingly recognised as an important zoonotic species. In the definitive host, infections with the adult ascarid usually do not present any clinical signs; if clinical signs do appear, it is usually in kittens infected with T. cati, especially by the transmammary route. Diseases may include cachexia, a pot-bellied appearance, respiratory disorders, diarrhoea, vomiting, among other signs, and these may present as early as 3 weeks of age. However, infections with Toxocara spp. larvae in paratenic hosts (including humans and many other animals), can result in serious complications from the migration of larvae. Historically, there has been an assumption that Toxocara canis was the most likely cause of Toxocara spp.-related disease; while it is probably true that T. canis is responsible for the majority of infections, it is important that those caused by T. cati are accurately identified so that the contribution of this parasite to human disease can be established and then handled appropriately. Overall, the detection of infections in cats and the control of parasite stages in the environment are essential to minimise the infection risk to other animals or humans.