Evaluation of Somatic Antigens of Adult Toxocara helminthes for Detection of Human Toxocariasis.

We aimed to develop an indirect enzyme-linked immunosorbent assay (ELISA) to evaluate the presence of specific IgG against Toxocara canis and Toxocara cati somatic antigens on the serum of patients with toxocariasis. The sensitivity, specificity, positive and negative predictive values for indirect-ELISA were calculated by receiver operating characteristic curve (ROC) analysis and Youden's J using Likelihood ratio. All statistics were analysed and graphs are plotted using GraphPad Prism version 8.4.3 (Graph Pad Software, La Jolla, CA, USA), with 95% confidence interval (CI). The sensitivity, specificity, positive and negative predictive values for T. canis were 100%, 82%, 79% and 100%, respectively. The mentioned variables for T. cati were 97%, 82%, 78% and 98%, respectively. Five immune reactive bands of 38, 40, 72, 100 and 250 kDa were common in both species. Toxocara crude antigens were highly immunogenic in human sera. Immunoreactive bands against T. canis compared to T. cati somatic antigen were about two times more. Unlike Toxocara excretory-secretory antigen, that was homologue in two species, somatic antigens of T. canis and T. cati showed different immunoreactive bands in our western blot.

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.

Relapse of toxocariasis after completion of four-week treatment with albendazole.

Food-borne toxocariasis caused by the consumption of raw meat or liver has occasionally been reported from East Asia. We treated a 38-year-old Japanese man who was infected with Toxocara in China and underwent a four-week treatment with albendazole. The liver and lung lesions disappeared after the treatment, suggesting that the treatment was successful. One month after the end of the treatment, the patient relapsed, and albendazole was administered again for eight weeks. The patient has remained relapse-free for one year. Although toxocariasis can heal spontaneously, in some cases, such as the present case, the disease relapses even after long-term treatment. In conclusion, different durations of treatment are recommended by various guidelines, and the duration of treatment needs to be modified with each case, considering the response to the treatment.

The larvicidal effect of the supernatant of Lactobacillus acidophilus ATCC 4356 on Toxocara canis.

Human toxocariasis is a parasitic anthropozoonosis that is difficult to treat and control. A previous study carried out with Lactobacillus acidophilus ATCC 4356 revealed that the cell free supernatant (CFS) of this probiotic killed 100% of Toxocara canis larvae in vitro. The present study aimed to investigate the characteristics of the CFS of L. acidophilus ATCC 4356, which may be involved in its larvicidal effects on T. canis. L. acidophilus ATCC 4356 was cultured, and lactic and acetic acids present in the CFS were quantified by high performance liquid chromatography (HPLC). The levels of pH and H2O2 were also analyzed. To assess the larvicidal effect of the CFS, this was tested pure and diluted (1:2 to 1:128) on T. canis larvae. High concentrations of lactic and acetic acids were detected in the CFS. The acidity of the pure CFS was observed at pH 3.8, remaining acidic at dilutions of 1:2 to 1:16. Regarding the in vitro larvicidal effect, 100% death of T. canis larvae was observed using the pure CFS and 1:2 dilution. Based on these results, it can be inferred that the presence of higher concentrations of organic acids and low pH of the medium contributed to the larvicidal activity of the CFS of L. acidophilus ATCC 4356. In addition, the maintenance of the larvicidal effect, even after dilution, suggests a greater chance of the larvicidal effect of this CFS against T. canis in vivo.

Synergistic effects of using sodium hypochlorite (bleach) and desiccation in surface inactivation for Toxocara spp.

Toxocara cati and T. canis are parasitic nematodes found in the intestines of cats and dogs respectively, with a cosmopolitan distribution, and the potential for anthropozoonotic transmission, resulting in human toxocariasis. Spread of Toxocara spp. is primarily through the ingestion of embryonated eggs contaminating surfaces or uncooked food, or through the ingestion of a paratenic host containing a third-stage larva. The Toxocara spp. eggshell is composed of a lipid layer providing a permeability barrier, a chitinous layer providing structural strength, and thin vitelline and uterine layers, which combined create a biologically resistant structure, making the Toxocara spp. egg very hardy, and capable of surviving for years in the natural environment. The use of sodium hypochlorite, household bleach, as a disinfectant for Toxocara spp. eggs has been reported, with results varying from ineffective to limited effectiveness depending on parameters including contact time, concentration, and temperature. Desiccation or humidity levels have also been reported to have an impact on larval development and/or survival of Toxocara spp. eggs. However, to date, after a thorough search of the literature, no relevant publications have been found that evaluated the use of sodium hypochlorite and desiccation in combination. These experiments aim to assess the effects of using a combination of desiccation and 10% bleach solution (0.6% sodium hypochlorite) on fertilized or embryonated eggs of T. cati, T. canis, and T. vitulorum. Results of these experiments highlight the synergistic effects of desiccation and bleach, and demonstrate a relatively simple method for surface inactivation, resulting in a decrease in viability or destruction of T. cati, T. canis and T. vitulorum eggs. Implications for these findings may apply to larger scale elimination of ascarid eggs from both research, veterinary, and farming facilities to mitigate transmission.

Comparison of extracellular vesicle isolation methods for the study of exosome cargo within Toxocara canis and Toxocara cati excretory secretory (TES) products.

Toxocara is a genus of nematodes, which infects a variety of hosts, principally dogs and cats, with potential zoonotic risks to humans. Toxocara spp. larvae are capable of migrating throughout the host tissues, eliciting eosinophilic and granulomatous reactions, while surviving for extended periods of time, unchanged, in the host. It is postulated that larvae are capable of altering the host's immune response through the release of excretory-secretory products, containing both proteins and extracellular vesicles (EVs). The study of EVs has increased exponentially in recent years, largely due to their potential use as a diagnostic tool, and in molecular therapy. To this end, there have been multiple isolation methods described for the study of EVs. Here, we use nanoparticle tracking to compare the yield, size distribution, and % labelling of EV samples acquired through various reported methods, from larval cultures of Toxocara canis and T. cati containing Toxocara excretory-secretory products (TES). The methods tested include ultracentrifugation, polymer precipitation, magnetic immunoprecipitation, size exclusion chromatography, and ultrafiltration. Based on these findings, ultrafiltration produces the best results in terms of yield, expected particle size, and % labelling of sample. Transmission electron microscopy confirmed the presence of EVs with characteristic cup-shaped morphology. These findings can serve as a guide for those investigating EVs, particularly those released from multicellular organisms, such as helminths, for which few comparative analyses have been performed.

Anthelmintic efficacy of nitazoxanide in dogs naturally infected with Toxocara canis.

Toxocara canis (T. canis) is a gastrointestinal nematode in dogs, and its larvae also infect humans, causing severe larval migratory disease. Anthelmintic drugs have become the primary means to combat T. canis. In this study, the efficacy of nitazoxanide (NTZ) was tested against all the internal stages of T. canis, including L3 larval stage in vitro experiments and gastrointestinal worm in vivo experiments. In the in vitro experiment, after treatment with NTZ at 7.81 and 62.5 µg/mL for 12 h, the larval mortality efficacy reached 90.0 and 100.0%, respectively. In the in vivo experiments, 100 mg/kg NTZ possessed good anthelmintic efficacy against T. canis, with an egg per gram (EPG) reduction of 99.19%, and 90.00% of dogs cleared with residual worms. These results were comparable to those of the positive control drug. The highest anthelmintic efficacy was observed in the group treated with 150 mg/kg NTZ. Based on faecal egg counts, the number of T. canis eggs decreased by 100.00%, and the percentage of dogs cleared with residual worms achieved 90.00% after 7 days of treatment in the 150-mg/kg NTZ treatment group. In general, NTZ showed great potential to be applied as an anthelmintic against T. canis.

Toxocarosis in a patient with autism spectrum disorder presenting with severe hypereosinophilia and acute respiratory distress: a case report.

A boy with known autism spectrum disorder was transferred to our department due to a rapidly worsening respiratory situation. The patient's history revealed previous treatment with albendazole against a Toxocara infection 2 weeks prior in Poland. Blood analysis showed such severe eosinophilia and markedly elevated levels of IgE that, initially, a hematologic malignancy was suspected. However, diagnostic workup including autoimmune diagnostic, molecular genetic testing, fluorescence in situ hybridization (FISH), bone marrow aspiration, and parasitological testing led to the diagnosis of an insufficiently treated Toxocara infection. Treatment with albendazole and prednisone (six cycles for 4 weeks each) was administered. This treatment regime led to prompt improvement of symptoms and normalization of laboratory findings.

Microscopic and molecular prevalence and associated risk factors with Toxocara and Blastocystis infection in dogs and cats in Mitidja, Algeria.

Domestic dogs and cats can serve as a source of environmental contamination with Toxocara spp. and Blastocystis spp., and this represents a neglected public and veterinary health problem. We assessed the microscopic and molecular prevalence of these species in a locality in Algeria and identified the associated risk factors. The faeces of 225 dogs and 78 cats were collected in Mitidja between March and July 2022. The samples were analysed by coproscopy and by polymerase chain reaction (PCR) targeting the Internal Transcribed Spacer 2 (ITS2) and Small Subunit Ribosomal (SSU-RNA) of T. canis and Blastocystis spp. respectively. The overall microscopic prevalence of Toxocara spp. in dogs and cats was 9.78 ± 1.98% and 12.82 ± 7.42%, respectively. The rate of Blastocystis spp. was 15.11 ± 2.39% and 15.38 ± 4.08% in dogs and cats, respectively while the molecular prevalence of T. canis in dogs was 4.89 ± 1.44% and in cats 1.28 ± 1.27%; the prevalence of Blastocystis spp. was 41.78 ± 3.29% and 34.62 ± 5.39% in dogs and cats, respectively. Phylogenetic and phylogeographic analyses identified the presence of the H1 subtype of T. canis in dogs, and the ST1 subtype of Blastocystis in dogs and cats. Dogs with clinical signs were more likely to be infected with T. canis (OR 6.039, P < 0.05) than healthy dogs. This study demonstrates that dogs and cats are carriers of Toxocara spp. and Blastocystis spp. and are therefore a source of environmental contamination. Veterinarians and human health professionals should work together to implement control strategies as part of a "One Health" approach to improving animal health and reducing the risk of transmission to humans.

Larvicidal activity of coumarin derivatives on Toxocara canis larvae, cytotoxicity analysis, and in silico bioavailability studies.

Human toxocariasis is a neglected anthropozoonosis with global distribution. Treatment is based on the administration of anthelmintics; however, their effectiveness at the tissue level is low to moderate, necessitating the discovery of new drug candidates. Several groups of synthetic compounds, including coumarin derivatives, have demonstrated bioactivity against fungi, bacteria, and even parasites, such as Dactylogyrus intermedius, Leishmania major, and Plasmodium falciparum. The aim of this study was to evaluate the effect of ten coumarin-derived compounds against Toxocara canis larvae using in vitro, cytotoxicity, and in silico tests for selecting new drug candidates for preclinical tests aimed at evaluating the treatment of visceral toxocariasis. The compounds were tested in vitro in duplicate at a concentration of 1 mg/mL, and compounds with larvicidal activity were serially diluted to obtain concentrations of 0.5 mg/mL; 0.25 mg/mL; 0.125 mg/mL; and 0.05 mg/mL. The tests were performed in a microculture plate containing 100 T. canis larvae in RPMI-1640 medium. One compound (COU 9) was selected for cytotoxicity analysis using J774.A1 murine macrophages and it was found to be non-cytotoxic at any concentration tested. The in silico analysis was performed using computational models; the compound presented adequate results of oral bioavailability. To confirm the non-viability of the larvae, the contents of the microplate wells of COU 9 were inoculated intraperitoneally (IP) into female Swiss mice at 7-8 weeks of age. This confirmed the larvicidal activity of this compound. These results show that COU 9 exhibited larvicidal activity against T. canis larvae, which, after exposure to the compound, were non-viable, and that COU 9 inhibited infection in a murine model. In addition, COU 9 did not exhibit cytotoxicity and presented adequate bioavailability in silico, similar to albendazole, an anthelmintic, which is the first choice for treatment of human toxocariasis, supporting the potential for future investigations and preclinical tests on COU 9.

Seroprevalence of Toxocara spp. in Pregnant Women: A Systematic Review and Meta-Analysis.

Background: Toxocariasis is an important health problem caused by the parasitic species Toxocara canis (T. canis) and Toxocara cati (T. cati). Prevalence of toxocariasis in pregnant women as a vulnerable population is doubly important, and the aim of this study is to estimate the overall prevalence of toxocariasis infection in pregnant women according to the available reports. Methods: The present study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklists. A systematic search was carried out in international scientific databases (Google Scholar, Web of Science, ScienceDirect, Scopus, and PubMed) between 1990 and 2023. The overall prevalence of parasitic infection was estimated with a random-effects model. All analyses (overall prevalence, heterogeneity, publication bias, and sensitivity analysis) were performed with comprehensive meta-analysis (V2.2, Bio stat) software. Results: Amid the final eleven included studies, based on the random-effects model, the estimation of the pooled prevalence of Toxocara spp. was 20.8% (95% CI, 9.8-38.7%). The association between the risk factors of toxocariasis and the prevalence of the disease was not statistically significant. Conclusions: In the present study, significant prevalence was reported; however, considering the limited number of studies, it seems that the actual prevalence of the disease is higher. Therefore, it seems necessary to monitor this health problem in pregnant women.

Sexual Dimorphism in the Physiopathology and Immune Response during Acute Toxocara canis Infection.

BACKGROUND: Toxocara canis (T. canis) is a helminth parasite of zoonotic and veterinary health significance that causes the disease known as Toxocariasis. This disease has been associated with conditions of poverty, especially in tropical climate zones throughout the world. Although it rarely causes important clinical manifestations, T. canis can lead to blindness, meningoencephalitis, or other nervous manifestations in humans. Moreover, some studies show its importance in the development of tumor growth, which have been associated with the parasite's ability to modulate the host's immune response. While different studies have evaluated the immune response during this disease, currently, there are no studies where the infection is analyzed from the perspective of sexual dimorphism. METHODS: To evaluate sex differences in susceptibility, we analyzed lesions and parasite loads in lung and liver at 7 days post-infection. In addition, immune cell subpopulations were analyzed in spleen, mesenteric and peripheral lymph nodes. Finally, the production of cytokines and specific antibodies were determined in the serum. Statical analyses were performed using a Two-way ANOVA and a post-hoc Bonferroni multiple comparison test. RESULTS: Female rats had a higher number of larvae in the liver, while male rats had them in the lungs. The percentages of immune cells were evaluated, and in most cases, no significant differences were observed. Regarding the cytokines production, infection can generate a decrease in Th1 such as IL-1ß in both sexes and IL-6 only in females. In the case of Th2, IL-4 increases only in infected males and IL-5 increases in males while decreasing in females due to the effect of infection. IL-10 also decreases in both sexes as a consequence of the infection, and TGF-ß only in females. Finally, the infection generates the production of antibodies against the parasite, however, their quantity is lower in females. CONCLUSIONS: This study demonstrates that T. canis infection is dimorphic and affects females more than males. This is due to a polarization of the inadequate immune response, which is reflected as a higher parasite load in this sex.

Case Report: Toxocariasis Manifesting as Eosinophilic Pleural Effusion.

Toxocariasis is a prevalent zoonosis caused by infection with the larvae of Toxocara canis or Toxocara cati. It ranges in severity from mundane to life-threatening, depending on organ involvement. The lungs are often affected, manifesting as coughing, wheezing, and chest pain. However, pleural effusions rarely occur in patients with pulmonary toxocariasis. We report the case of a 74-year-old man with highly suspected toxocariasis who presented with an eosinophilic pleural effusion and eosinophilia. He developed dyspnea and a right-sided pleural effusion. Thoracentesis revealed an exudative effusion containing numerous eosinophils. The pleural effusion continued to increase, and the eosinophilia rapidly progressed. Although the patient had not recently had contact with animals or known exposure to contaminated food, water, or soil, toxocariasis was confirmed by positive serological test results for anti-Toxocara antibodies in the serum and pleural effusion. The patient was cured with albendazole treatment for 28 days. The pleural effusion and eosinophilia resolved and did not recur. Clinicians should consider toxocariasis in the differential diagnosis of patients presenting with eosinophilic pleural effusions.

Dynamics of ex vivo cytokine transcription during experimental Toxocara canis infection in Balb/c mice.

The cytokine microenvironment is crucial in generating and polarizing the immune response. A means of monitoring this environment would be of great value for better understanding Toxocara canis immune modulation. The aim of this study was to analyze the dynamics of cytokine transcription ex vivo, during early (24-48 hours) and late (15-30 days) times post-infection, in the mesenteric lymph nodes, spleen and intestinal mucosa of Balb/c mice experimentally infected with T. canis larvae. Mice in the treated group were infected with 100 third-stage larvae (L3), whereas mice in the control group were not infected. Analyses were performed at different times: 24-48 hours post-infection (HPI), 15-30 days post-infection (DPI). IL4, IL10, IL12 and Ym1 mRNA transcriptions were analyzed through qPCR. This study showed cytokine transcription mediated by migrating larvae in the mesenteric lymph nodes and spleen at 24-48 HPI, whereas cytokine transcription in the intestinal mucosa was observed only at late times (15-30 DPI). These results suggest that the T. canis larvae migration during infection might play a role in cytokine dynamics. Since the cytokine microenvironment is crucial in modulating immune response, knowledge of cytokine dynamics during T. canis infections pave the way to better understand its interaction with the host.

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.

Global Seroprevalence of Toxocara spp. in Children: A Systematic Review and Meta-analysis.

BACKGROUND: In the present study, we performed a systematic review and meta-analysis to assess the global and regional seroprevalence of Toxocara spp. and associated risk factors among children. METHODS: The present systematic review and meta-analysis was followed based on the Preferred Reporting. Items for Systematic Reviews and Meta-analyses (PRISMA) protocol. We searched the online databases (PubMed, Scopus, and Web of Science) and Google Scholar search engine for studies that measured seroprevalence of Toxocara spp. among children, published between 1 January 2000 and 15 January 2022. Accordingly, the pooled seroprevalence and 95% confidence intervals (CI) were estimated using a random-effects meta-analysis model. RESULTS: A total of 65 articles from 22 countries met the inclusion criteria. The global seroprevalence of Toxocara spp. infection among children was estimated as 25% (95% CI 22-29). Meta-regression analysis showed that the type of population studied (p = 0.002) and year of publication (p = 0.044) it may be the source of heterogeneity. The highest and lowest pooled seroprevalence of Toxocara spp. infection were estimated in Thailand and Colombia as 58.2% (95% CI 50.9-65.5) and 7.04% (95% CI 3.05-11.3), respectively. Male gender was associated with a higher risk of Toxocara spp. compared to females, and this association was statistically significant (OR = 1.24; 95% CI 1.09-1.41, p = 0.001). However, residing in rural areas did not show a statistically significant increase in risk compared to living in urban areas (OR = 1.39; 95% CI 0.88-2.21, p = 0.143). CONCLUSION: Toxocariasis is common among children, hence, prevention and control scheme of this helminth in children should be considered by health officials and health policymakers, especially in developing countries, where seroprevalence is highest.

Proteomic change in the upper lobe of the left lung of Beagle dogs at the lung migration stage of Toxocara canis infection.

BACKGROUND: Toxocara canis is considered one of the most neglected parasitic zoonoses and threatens the health of millions of people worldwide with a predilection for pediatric and adolescent populations in impoverished communities. Exploring the invasion and developmental mechanisms associated with T. canis infection in its definitive canine hosts will help to better control zoonotic toxocariasis. METHODS: Proteomic changes in samples from the upper lobe of the left lung of Beagle puppies were systematically analyzed by quantitative proteomic technology of data-independent acquisition (DIA) at 96 h post-infection (hpi) with T. canis. Proteins with P-values < 0.05 and fold change > 1.5 or < 0.67 were considered proteins with differential abundance (PDAs). RESULTS: A total of 28 downregulated PDAs and 407 upregulated PDAs were identified at 96 hpi, including RhoC, TM4SFs and LPCAT1, which could be associated with the maintenance and repair of lung homeostasis. GO annotation and KEGG pathway enrichment analyses of all identified proteins and PDAs revealed that many lung proteins have correlation to signal transduction, lipid metabolism and immune system. CONCLUSIONS: The present study revealed lung proteomic alterations in Beagle dogs at the lung migration stage of T. canis infection and identified many PDAs of Beagle dog lung, which may play important roles in the pathogenesis of toxocariasis, warranting further experimental validation.

Epidemiological profile of human toxocariasis in patients examined at Evandro Chagas Institute (IEC/SVSA/MS) between 2014 and 2019.

INTRODUCTION: Toxocariasis is caused by nematodes of Toxocara genus, which infest dogs and cats, with humans serving as paratenic hosts. METHODS: The epidemiological profile of patients examined for toxocariasis between October 2014 and October 2019 at Evandro Chagas Institute (IEC) was outlined. The frequency of anti-T. canis IgG antibodies were evaluated using the Enzyme Linked Immunosorbent Assay (ELISA) method. RESULTS: From a total of 734 samples, 56% were from male (p < 0.05). Regarding age, the group with the most solicitations were from ≤11 years old individuals (p < 0.05). Pará state had the highest number of exams requested (92%), with the majority from residents of urban areas, accounting for 81.5% of samples (p < 0.05). The overall toxocariasis seroprevalence was 41.8%, the male sex being the most frequent with 60.9% (p < 0.05). The most affected age group was ≤11 years old, with a total of 67.8% of positive samples (p < 0.05). CONCLUSION: The high rates obtained emphasize the need for complementary studies on toxocariasis in Brazil, especially in Pará state, contributing to epidemiological surveillance actions in the control of this infection. Besides, health campaigns for domestic and stray animals, also can contribute to a more effective surveillance in controlling parasitic infections and encourages the One Health approach.

Intestine proteomic and metabolomic alterations in dogs infected with Toxocara canis.

Toxocariasis is an important zoonotic parasitic disease. Toxocaris canis adults live and reproduce in the intestinal tract of dogs and other canine hosts, and the infectious eggs are continuously excreted in feces, which causes environmental contamination and has an important public health significance. In this study, TMT proteomic and untargeted metabolomic methods were used to explore the physiological and pathological effects on the intestinal tract of dogs which infected with T. canis, and a series of bioinformatics analyses were conducted to identify differentially expressed proteins (DEPs) and differentially expressed metabolites (DEMs). The proteomics results showed that 198 DEPs were mainly enriched in the immune system and signal transduction pathway, and involved in the regulation of the occurrence and development of cancer and infectious diseases. T. canis could disrupt intestinal permeability by increasing the expression of proteins such as zinc finger protein DZIP1L and myosin heavy chain 10. Additionally, T. canis infection could also inhibit the host immune response by decreasing the expression of MHC-II, NF-κB, DLA and other immune-related molecules. While, the metabolomics results revealed that the expression of oxoglutaric acid, glutamate, d-aspartate, arginine, taurochenodeoxycholic acid and taurocholic acid which participated in tricarboxylic acid (TCA) cycle, glycolysis/gluconeogenesis, bile secretion, biosynthesis of amino acids pathway were significantly decreased. The correlation results of proteomics and metabolomics showed that DEPs and DEMs were mainly co-enriched in bile secretion pathway to regulate intestinal peristalsis. Analyzing DEPs and DEMs will not only provide insights into the mechanisms of host parasite interaction, but also aid in identifying potential targets for therapy and diagnosis, thus setting the groundwork for effectively preventing and managing toxocariasis.

[Atypical ocular toxocariasis in a child: A case report]. / Toxocarose oculaire atypique chez un enfant : à propos d'un cas.

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.