Toxocara Canis Infection Research Articles

Clinical and laboratory characteristics of Toxocara canis infection among children in Ho Chi Minh City, Vietnam.

This study determines the clinical and paraclinical characteristics of children with Toxocara canis infection and serum eosinophil cut-off values for predicting toxocariasis in the group displaying symptoms of itching, urticaria and erythema. A cross-sectional study was conducted during March and April 2023 with a sample size of 986 children aged 3-15 y. In total, 140 (14.2%) of the 986 participants had anti-T canis antibodies. The most frequently experienced symptoms in this group were itching (10.1%), abdominal pain (8.2%) and urticaria (3.3%). The rate of IgE increased (37%), and the rates of mild and high eosinophilia were 38% and 2.2%, respectively. There were significant differences in IgE concentration and eosinophil count, and for both IgE concentration and eosinophil count between the two groups with and without toxocariasis. The optimal threshold for eosinophil to predict toxocariasis was 0.38 K/µL, with itching, urticaria and erythema resulting in a sensitivity of 61.5%, a specificity of 82.1% and a receiver operating characteristic curve (area under the curve) of 0.71. This study confirmed a positive association between IgE concentration, eosinophil count and positive serology for T. canis. A general blood count, including eosinophils, is a simple test that can be performed in hospitals. Clinicians should target and screen for T.oxocara canis infection when children display clinical symptoms of itching, urticaria, erythema and eosinophilia. NCT05208333.

Multifactorial case of ascites and anemia in a Golden Retriever involving Babesia sp. and Toxocara canis infections

A seven-year-old male Golden Retriever presented with lethargy, anorexia, abdominal enlargement, and weakness. Hematology tests revealed lymphocytosis, microcytic hypochromic anemia with anisocytosis, hypoalbuminemia, hyperglobulinemia, and elevated levels of alkaline phosphatase (ALP), blood urea nitrogen (BUN), and creatinine. Radiographic examination showed pneumonia, an abnormal heart shape resembling an inverted "D," and fluid accumulation in the abdominal cavity. Blood smears indicated a Babesia sp. infection. Additionally, the dog expelled a worm identified as Toxocara canis. The complex interaction between T. canis infection, multiple organ dysfunction, Babesia sp. infection, and malnutrition contributed to the development of ascites and anemia in this case. Treatment included abdominocentesis and fluid therapy. The dog was also prescribed furosemide, methylprednisolone, digoxin, Hematodin®, VipAlbumin®, and Drontal® for the worm infection. Unfortunately, the dog died on the 5th day of treatment due to dehydration and worsening anemia.

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

BackgroundToxocara 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.MethodsProteomic 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).ResultsA 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.ConclusionsThe 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.Graphical

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 2months. 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 2000T. canis eggs and gerbils infected with 1000, 2000 and 4000T. canis eggs showing obvious ocular lesions and lower mortality rates could provide a basis for long-term observation.

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.

Clinical variability of Toxocara canis infection in children

Toxocariasis maintains significant relevance at present. This study focuses on presenting the diversity of clinical symptoms and the specific clinical course of toxocariasis in children. Early diagnosis becomes crucial for initiating effective antiparasitic treatment, thereby contributing to reducing the risk of recurrence and chronicity of the condition.

Toxocara canis-induced changes in host intestinal microbial communities

BackgroundToxocara canis is a roundworm that resides in the gastrointestinal tract of dogs and causes various pathological changes. The dog’s intestinal system consists of a diverse and dynamic bacterial community that has extensive effects on intestinal physiology, immunity and metabolics. In the case of intestinal parasites, interactions with the host intestinal flora are inevitable during the process of parasitism.MethodsWe studied the role of T. canis in regulating the composition and diversity of the intestinal flora of the host by high-throughput sequencing of the 16S ribosomal RNA gene and various bioinformatics analyses.Results The α-diversity analysis showed that Toxocara canis infection resulted in a significant decrease in the abundance and diversity of host intestinal flora. The β-diversity analysis showed that the intestinal flora of infected dogs was similar to that carried by T. canis. Analysis of the microflora composition and differences at the phylum level showed that the ratio of Firmicutes to Bacteroidetes (F/B ratio) increased with T. canis infection. Analysis of species composition and differences at the genus level revealed that the proportion of some of the pathogenic bacteria, such as Clostridium sensu stricto and Staphylococcus, increased after T. canis infection.ConclusionsToxocara canis infection affected the composition and diversity of the flora in the host intestinal tract. These results not only shed light on the potential mechanism of T. canis invasion and long-term survival in the intestinal tract, but also provide a new basis for the development of anthelmintic drugs.Graphical

Update on the role of genetic factors, environmental factors and allergens in canine atopic dermatitis.

Canine atopic dermatitis (cAD) is a common, complex and multifactorial disease involving, among others, genetic predisposition, environmental factors and allergic sensitisation. This review summarises the current evidence on the role of genetic and environmental factors and allergic sensitisation in the pathogenesis of cAD since the last review by ICADA in 2015. Online citation databases and proceedings from international meetings on genetic factors, environmental factors and allergens relevant to cAD that had been published between 2015 and 2022 were reviewed. Despite intensive research efforts, the detailed genetic background predisposing to cAD and the effect of a wide range of environmental factors still need more clarification. Genome-wide association studies and investigations on genetic biomarkers, such as microRNAs, have provided some new information. Environmental factors appear to play a major role. Lifestyle, especially during puppyhood, appears to have an important impact on the developing immune system. Factors such as growing up in a rural environment, large size of family, contact with other animals, and a nonprocessed meat-based diet may reduce the risk for subsequent development of cAD. It appears that Toxocara canis infection may have a protective effect against Dermatophagoides farinae-induced cAD. House dust mites (D. farinae and D. pteronyssinus) remain the most common allergen group to which atopic dogs react. Currently, the major allergens related to D. farinae in dogs include Der f 2, Der f 15, Der f 18 and Zen 1. Canine atopic dermatitis remains a complex, genetically heterogeneous disease that is influenced by multiple environmental factors. Further, well-designed studies are necessary to shed more light on the role of genetics, environmental factors and major allergens in the pathogenesis of cAD.

Prevalence and risk factors associated with Toxocara canis in dogs and humans in Egypt: A comparative approach.

Dogs are the most popular pet animals worldwide, and their frequent and close contact with humans poses an increased risk of zoonotic parasite transmission. Toxocara canis infection is a highly pervasive and economically significant zoonotic infection transmitted by dogs worldwide, commonly in tropical and subtropical regions, particularly in developing countries. This study evaluates the epidemiological profile and associated risk factors of T. canis exposure among humans and T. canis infection in domestic dogs in two climatically different governorates in Egypt. Faecal samples from 360 domiciled dogs were examined using the flotation technique to detect T. canis eggs. In addition, 276 human serum samples were evaluated by enzyme-linked immunosorbent assay over a period of 10 months from May 2021 to February 2022 in the Alexandria and Qena Governorates, Egypt. Shedding of T. canis was identified in 33.33% (120/360) of dogs and the overall seroprevalence in the human population was 20.65% (57/276). Lower Egypt, represented by the Alexandria Governorate, had higher canine infection (39.47%) and human seropositivity (29.87%) rates than those of Upper Egypt, represented by Qena Governorate (26.47% and 9.02% in dogs and humans, respectively). Statistical analysis of the sociodemographic characteristics of the participants revealed that handwashing, washing of vegetables and fruits and sex were associated with human T. canis exposure. The prevalence rates of confirmed T. canis infection in the Egyptian dogs population and the associated human seropositivity rates reflect its importance as a public health concern and support the call to increase public awareness of this issue. The risk factors identified in this study can contribute to the development of more effective control and prevention strategies.

Unveiling the Zoonotic Significance of Toxocariasis in Humans: The Role of Toxocara canis

Toxocariasis is a zoonotic disease caused by the parasite Toxocara canis, with significant effects on human health. This article provided a comprehensive overview of the importance of complications of Toxocara canis infection. The introduction highlighted the relevance of zoonotic diseases and introduced toxocariasis as a specific example. The subsequent sections delved into toxocariasis, covering its transmission, lifecycle, host specificity, and primary sources of human infection. The epidemiology section presented the global prevalence and distribution of toxocariasis at 11.1% (95% CI: 10.6–11.7%), emphasizing high-risk groups and geographical factors contributing to illness. Detailed information was provided regarding the clinical manifestations of toxocariasis, including variations in disease severity and potential complications. Symptoms of visceral toxocariasis include fever, fatigue, coughing, wheezing, or abdominal pain. The diagnostic methods include laboratory methods (serological testing and western blot) and molecular techniques (PCR), and clinical methods (chest X-ray and CT scan). The prevention and control section outlined strategies for prevention, highlighting the significance of public health measures and awareness campaigns. The One Health approach has recognized the interconnections between human, animal, and environmental health. It has highlighted the necessity of cooperative actions to prevent the spread of diseases that can be transmitted between animals and humans. Future directions need to highlight ongoing research and advancements, including improved diagnostic tools, targeted therapies, risk assessment, and international collaboration. The conclusion reinforces the importance of understanding and addressing Toxocara canis infection on human health. Adopting a One Health approach and implementing effective prevention, diagnosis, and treatment strategies can reduce the burden of toxocariasis, leading to improved health outcomes for humans and animals.

Clinical and therapeutic management of erratic movement of parasites in young dogs

Parasitic infection (both ecto – endo parasites) causes greater economic losses to Live Stock and Poultry. Young puppies suffered with Toxocara canis infection. Totally 32 numbers of puppies at the age group of 2-5 months showed symptomatic worm infestation with bot belly appearance and few of them showed adult ascaris worms in vomit and few of the showed unilateral nasal sneezing. Presence of worms in vomitus may be associated with their erratic movements, some round worms may enter in to stomach and may be vomited and some worms may enter the bile ducts and produce obstructive jaundice and cholangitis. Prenatal and trans mammary route of infection play a major role for transmission of infection.

Modulation of long noncoding RNA (lncRNA) and messenger RNA (mRNA) expression in the liver of Beagle dogs by Toxocara canis infection

BackgroundLong non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) play crucial roles in regulating various physiological and pathological processes. However, the role of lncRNAs and mRNAs in mediating the liver response during Toxocara canis infection remains incompletely understood.MethodsIn the present study, the expression profile of lncRNAs and mRNAs was investigated in the liver of Beagle dogs infected by T. canis using high-throughput RNA sequencing.ResultsCompared with the control groups, 876 differentially expressed (DE) lncRNAs and 288 DEmRNAs were identified at 12 h post-infection (hpi), 906 DElncRNAs and 261 DEmRNAs were identified at 24 hpi, and 876 DElncRNAs and 302 DEmRNAs were identified at 36 days post-infection (dpi). A total of 16 DEmRNAs (e.g. dpp4, crp and gnas) were commonly identified at the three infection stages. Enrichment and co-localization analyses identified several pathways involved in immune and inflammatory responses during T. canis infection. Some novel DElncRNAs, such as LNC_015756, LNC_011050 and LNC_011052, were also associated with immune and inflammatory responses. Also, LNC_005105 and LNC_005401 were associated with the secretion of anti-inflammatory cytokines, which may play a role in the healing of liver pathology at the late stage of infection.ConclusionsOur data provided new insight into the regulatory roles of lncRNAs and mRNAs in the pathogenesis of T. canis and improved our understanding of the contribution of lncRNAs and mRNAs to the immune and inflammatory response of the liver during T. canis infection.Graphical

Vicarious excretion of contrast medium to small intestine in a dog with Toxocara canis infection

A male mixed-breed dog of unknown age was presented with a history of bloody diarrhea and cachexia. Toxocara canis in vomitus was identified by a parasitologist. Hematology revealed low hematocrit, eosinophilia, and low albumin. Computed tomography (CT) revealed an enlarged pulmonary artery with an irregular wall, micronodules in the lung, and vicarious excretion of contrast medium to small intestine. CT scan was helpful for identifying lung lesions and the central organs of larval migration and also show vicarious excretion of contrast medium to the small intestine in T. canis infection.

Differential miRNA expression profiles in the bone marrow of Beagle dogs at different stages of Toxocara canis infection

BackgroundToxocara canis is distributed worldwide, posing a serious threat to both human and dog health; however, the pathogenesis of T. canis infection in dogs remains unclear. In this study, the changes in microRNA (miRNA) expression profiles in the bone marrow of Beagle dogs were investigated by RNA-seq and bioinformatics analysis.ResultsThirty-nine differentially expressed (DE) miRNAs (DEmiRNAs) were identified in this study. Among these, four DEmiRNAs were identified at 24 h post-infection (hpi) and all were up-regulated; eight DEmiRNAs were identified with two up-regulated miRNAs and six down-regulated miRNAs at 96 hpi; 27 DEmiRNAs were identified with 13 up-regulated miRNAs and 14 down-regulated miRNAs at 36 days post-infection (dpi). Among these DEmiRNAs, cfa-miR-193b participates in the immune response by regulating the target gene cd22 at 24 hpi. The novel_328 could participate in the inflammatory and immune responses through regulating the target genes tgfb1 and tespa1, enhancing the immune response of the host and inhibiting the infection of T. canis at 96 hpi. In addition, cfa-miR-331 and novel_129 were associated with immune response and self-protection mechanisms at 36 dpi. 20 pathways were significantly enriched by KEGG pathway analysis, most of which were related to inflammatory response, immune response and cell differentiation, such as Cell adhesion molecules (CAMs), ECM-receptor interaction and Focal adhesion.ConclusionsThese findings suggested that miRNAs of Beagle dog bone marrow play important roles in the pathogenesis of T. canis infection in dogs and provided useful resources to better understand the interaction between T. canis and the hosts.

Toxocariasis in children with digestive system diseases

Toxocariasis is common among children and causes digestive diseases. The aim of the work was to study the development of toxocariasis in children with digestive diseases. The serum levels of specific IgG to Toxocara canis and Ascaris, levels of IL-4 and TNF-α were determined in 63 children. In addition, tests for parasites and a retrospective survey in order to assess sanitation and hygiene practices were conducted. All children were divided into two groups: group I includes 19 (30.2%) patients seropositive for toxocariasis, and group II – 44 (69.8%) children without any parasites. The level of IL-4 was higher in group I (18.0 ± 6.4 pg/ml) than in group II (7.2 ± 2.0 pg/ml) (P &lt; 0.001. While the level of TNF-α did not differ significantly between groups I (4.5 ± 2.1 pg/ml) and II (3.6 ± 1.1 pg/ml) (P &gt; 0.05). A higher incidence of Toxocara was observed among rural residents (78.9%). Children with toxocariasis more often had soil-pica (42.1%), played with dogs (100%), and did not wash their hands (84.2%) compared to the group of uninfected children. It was noted that hygienic habits and place of living contribute to Toxocara canis infection. IL-4 levels were considerably higher in group I than in group II that can be accounted for the host immune response activation, at the same time, the levels of TNF-α did not differ. Children without toxocariasis had also increased levels of IL-4, which may be related to past helminthic infection. Keywords: children., digestive diseases, interleukin-4, toxocariasis, tumor necrosis factor - α

Eosinophilia caused by Toxocara canis infection

Eosinophilia is defined as an absolute peripheral blood eosinophil count &gt; 0.5 GL. Most often, its intensity is mild. Eosinophilia usually accompanies other diseases such as allergic, rheumatological, infectious, or oncological. The signs depend on the underlying diseases. After starting treatment of the underlying disease, the eosinophil count returns to the reference range. The diagnosis of eosinophilia starts by excluding the secondary causes. Clonal eosinophilia is a rare disease in which eosinophils are part of a tumor clone. The clonality is confirmed by molecular biology methods. The most common eosinophilic infiltration includes skin, lungs, and heart. The symptoms are not connected with a count of eosinophils in blood or bone marrow. The manifestation can be mild but also severe, life-threatening like venous thromboembolism. This article presents a case of 36-year-old man with eosinophilia caused by Toxocara canis infection manifested by systemic symptoms, erythroderma, and liver failure.

Coprological detection of Toxocariosis in domicile and stray dogs and cats in Sulaimani province, Iraq

Toxocara canis and Toxocara cati are ascarid nematodes, belong to the Toxocaridae family and genus Toxocara, causing toxocariosis in dogs and cats. The disease is mainly transmitted between animals and humans through ingestion of contaminated food with the embryonated eggs of the parasite. In addition, vertical transmission of the Toxocara larvae from pregnant bitches to their offspring through placenta and milk has been reported. Nowadays, stray dogs and cats, which are unvaccinated or not treated against the parasites, play a significant role in introducing the disease and seem to be a common public health concern. The study aimed to identify the rate of Toxocara canis and Toxocara cati infection among the domiciliary and stray dogs and cats that presented to the veterinary clinics, using direct fecal smear and fecal floatation techniques. The results showed that stray cats were highly infected 47.62% in comparison to domiciled cats 5.56%. In contrast, the T. canis infection among domiciled and stray dogs was about 11.11% and 11.76%, respectively. Adult cats and dogs were found to have a higher infectious rate cat; 30%, dogs; 14.81% than younger age groups cats; 27.58%, dogs; 8%. There was a moderate and highly significant positive correlation between the lifestyle and infectious rate in cats. In conclusion, stray cats and dogs are the leading risk factor for transmitting the disease.

Lipidomic changes in the liver of beagle dogs associated with Toxocara canis infection.

A global lipidomic analysis using liquid chromatography–tandem mass spectrometry was performed on the liver of beagle dogs infected with Toxocara canis to profile hepatic lipid species at 12 h post-infection (hpi), 24 hpi, and 36 days post-infection (dpi). This analysis identified six categories and 42 subclasses of lipids, including 173, 64, and 116 differentially abundant lipid species at 12 hpi, 24 hpi, and 36 dpi, respectively. Many of the identified lysophospholipids, such as lysophosphatidylglycerol, lysophosphatidylserine, and lysophosphatidylcholine, may contribute to the migration and development of T. canis during the early infection stage. Pathway analysis revealed significant alterations of several immune-inflammatory pathways, such as the B-cell receptor signaling pathway, the NF-kappa B signaling pathway, and the C-type lectin receptor signaling pathway at 12 and 24 hpi. These findings demonstrate the value of lipidomic profiling in revealing the extent of changes in the composition and abundance of hepatic lipidome caused by T. canis infection and their relevance to the pathophysiology of toxocariasis in beagle dogs.

Prevalence of Toxocara canis infection in dogs and Toxocara egg environmental contamination in Baybay City, Leyte, Philippines.

The online version contains supplementary material available at 10.1007/s12639-022-01525-y.

IL-17RA receptor signaling contributes to lung inflammation and parasite burden during Toxocara canis infection in mice.

IL-17 is a cytokine produced by innate and acquired immunity cells that have an action against fungi and bacteria. However, its action in helminth infections is unclear, including in Toxocara canis infection. Toxocariasis is a neglected zoonosis representing a significant public health problem with an estimated seroprevalence of 19% worldwide. In the present study, we describe the immunopathological action of IL-17RA in acute T. canis infection. C57BL/6j (WT) and IL-17RA receptor knockout (IL-17RA-/-) mice were infected with 1000 T. canis eggs. Mice were evaluated 3 days post-infection for parasite load and white blood cell count. Lung tissue was harvested for histopathology and cytokine expression. In addition, we performed multiparametric flow cytometry in the BAL and peripheral blood, evaluating phenotypic and functional changes in myeloid and lymphoid populations. We showed that IL-17RA is essential to control larvae load in the lung; however, IL-17RA contributed to pulmonary inflammation, inducing inflammatory nodular aggregates formation and presented higher pulmonary IL-6 levels. The absence of IL-17RA was associated with a higher frequency of neutrophils as a source of IL-4 in BAL, while in the presence of IL-17RA, mice display a higher frequency of alveolar macrophages expressing the same cytokine. Taken together, this study indicates that neutrophils may be an important source of IL-4 in the lungs during T. canis infection. Furthermore, IL-17/IL-17RA axis is important to control parasite load, however, its presence triggers lung inflammation that can lead to tissue damage.