ЗАРАЖЕННОСТЬ ТОКСОКАРОЗОМ (TOXOCARA CANIS, WERNER, 1782) ДОМАШНИХ СОБАК В ОДНОМ ИЗ ОКРУГОВ Г. МОСКВЫ

Treatment of larva migrans syndrome with long-term administration of albendazole.

Toxocariasis is a helminthic zoonosis caused by the presence and migration of animal nematode larvae in human tissue – mostly Toxocara canis and Toxocara cati. The term visceral larva migrans syndrome was used for the first time in 1952 by Beaver et al. who described the typical clinical presentation. There are difficulties in the diagnosis of toxocariasis because of the variety of symptoms depending on the larva localisation in different tissues and organs. Currently, the most commonly used serological methods are ELISA and Western blot. The disease is characterised by diverse clinical picture and thus toxocariasis is very rarely identified and most patients remain undiagnosed, which requires in-depth study of this widespread but still problematic zoonosis.

Introduction: According to the World Health Organization, Toxocara canis, a nematode in the order Ascarididia, is an epidemic and epizootic risk factor for humans and animals around the world and in the Russian Federation. Human toxocariasis is one of the commonest parasitic zoonoses with up to 900 million incident cases registered annually in different age and social groups of the population and a global public health problem of our time. Objective: To study the nematode Toxocara canis (Werner, 1782) as a health risk factor for the population of southern regions the Russian Federation. Materials and methods: We estimated the incidence of larval toxocariasis in the population of 10 districts and two cities of Karachay-Cherkessia based on the results of enzyme immunoassay of blood samples of 6,000 people in 2019–2022. The Tiascar diagnostic test kit (2017) was applied showing toxocariasis for the antibody titer ≥ 1:800 and infestation with Toxocara larvae for those of 1:200 and 1:400. The stool ova and parasite test was used to study 600 dog stool samples from the study areas. In addition, 1,200 soil samples were tested for the presence of Toxocara canis eggs. Results: We established that the incidence rate of larval toxocariasis in the population of 10 districts and two cities of Karachay-Cherkessia varied from 2.00 to 5.40 %. Toxocara canis larvae were not found in human feces, since humans are a biological dead end for this species of worms. Toxocara canis infestation rates in feces of dogs ranged from 2.7 ± 0.4 to 6.9 ± 0.8 eggs/g, potentially accounting for a high level of soil contamination with eggs. The current epidemic situation of human toxocariasis in the Karachay-Cherkess Republic is relatively favorable owing to planned preventive measures. Yet, this constituent entity is at risk of the disease in the future since the number of children, adults and migrants with larval toxocariasis shows a dynamic growth throughout the year. Conclusion: Incidence rates of larval toxocariasis in the child population and migrants demonstrate a 2.74–2.78-fold increase during the year. Toxocara canis eggs contaminate 46 to 94 % of soils in different areas of the republic posing high risks of larval toxocariasis for the local population. In terms of canine toxocariasis, the Karachay-Cherkess Republic can be attributed to disadvantaged territories of the North Caucasian Federal District.

Toxocariasis is a zoonotic disease that affects humans and animals alike. Although recombinant proteins are widely used for its diagnosis in humans, their performance in companion and production animals remains unknown. This study aimed to investigate the serodiagnostic potential of the recombinant proteins rTES–30 and rTES–120 from Toxocara canis in an indirect ELISA for cattle, horses, and sheep. Serum samples collected from the animals were tested with indirect ELISA and Western Blotting using T. canis TES–30 and TES–120 recombinant proteins produced in Escherichia coli, as well as native-TES. In the ELISA, rTES–30 showed high serodiagnostic potential in sheep and horses (92.6% and 85.2%, respectively), while the sensitivity of rTES–120 was higher in cattle and horses (97.2% and 92.6%, respectively). Furthermore, a highly positive association was observed between native and recombinant proteins in seropositive samples, while a moderately positive association was observed in seronegative samples, probably due to the lower specificity of native TES. In conclusion, our study indicates that the use of recombinant proteins in an indirect ELISA is an effective tool for the serodiagnosis of toxocariasis in animals, with the choice of protein being species-dependent.

Therapeutic battle against larval toxocariasis: Are we still far behind?

Larva migrans syndrome (LMS) caused by Toxocara and Ascaris roundworms is generally believed to be more common in children, while a report from Japan suggests that it is more common in adults. We conducted a large-scale retrospective study to confirm these findings and to clarify what caused the difference between Japan and other countries, to reveal overlooked aspects of this disease. The clinical information of 911 cases which we diagnosed as Toxocara or Ascaris LMS during 2001 and 2015 was analysed. Information used included age, sex, address (city or county), chief complaint, present history, dietary history, overseas travelling history, medical imaging findings and laboratory data (white blood cell count, peripheral blood eosinophil number and total IgE). The sex ratio of the disease was 2.37 (male/female = 641/270). The number of patients not younger than 20 years old were 97.8 and 95.1 % among males and females, respectively. Major disease types were visceral, ocular, neural and asymptomatic. The visceral type was more prevalent in older patients, while younger patients were more vulnerable to ocular symptoms. More than two-thirds of the patients whose dietary habits were recorded had a history of ingesting raw or undercooked animal meat. LMS caused by Toxocara or Ascaris is primarily a disease of adult males in Japan, who probably acquired infections by eating raw or undercooked animal meat/liver. Healthcare specialists should draw public attention to the risk of raw or undercooked animal meat in Europe as well.

In connection with the increasing incidence of patients with skin manifestations of helminth infections after visiting endemic zones, dermatovenereologists need to know the skin manifestation of tropical countries diseases. At present, serpeginating dermatitis often causes difficulties in the diagnosis and choice of treatment tactics. Tissue helminthiasis is a skin disease caused by the parasitization of migratory zohelminth larvae, for which a person is an intermediate host. Infection is most often affected by people who come into contact with warm, moist, sandy soil contaminated by dog and cat feces. This article presents a clinical case of a patient with a diagnosis of the skin form of “larva migrans syndrome” treated with two courses of the anthelmintic drug of the benzimidazole group in a daily dose of 800 mg with regressing the dermatological manifestations of the disease within 2 weeks from the start of specific therapy.

Visceral larva migrans (VLM) syndrome caused by Toxocara canis larvae was first described in the 1950s. The role of other nematode larvae, i.e. the pig roundworm Ascaris suum as a causative agent of visceral larva migrans-associated symptoms like general malaise, cough, liver dysfunction, hypereosinophilia with hepatomegaly and/or pneumonia, was discussed controversially during the last decades. Recent serological screening studies for specific A. suum antibodies carried out in the Netherlands and Sweden yielded remarkable high seroprevalences, while a number of case reports from Japan report pulmonal, hepatic and cerebral symptoms caused by A. suum larvae after ingestion of infected raw meat (liver) or contaminated vegetables. We present here a sensitive and specific larval excretory-secretory (E/S) antigen-based immunoblot (As-IB) for the serodiagnosis of A. suum-infected patients suffering from symptoms associated to the VLM syndrome. In total, 34 sera from patients with hypereosinophilia and other clinical symptoms associated to the VLM syndrome tested negative for Toxocara sp. antibodies but positive in our newly established As-IB, 30 sera from healthy volunteers, 53 sera from patients with clinically and serologically confirmed toxocarosis and other helminthoses as well as 3 sera from patients with intestinal ascariosis due to Ascaris lumbricoides were included in the study. When evaluated with 30 sera from healthy volunteers and 53 sera from patients suffering from different helminthoses, the calculated specificity of our new As-IB is 95%. Problems hampering the establishment of simple serological screening tests for specific A. suum antibodies, like extensive antigenic similarities between the nematodes Ascaris and Toxocara or the absence of suitable experimental animals, are discussed. We assume that specific serological testing for antibodies of A. suum is very important for the treatment of individual patients on one hand and seroepidemiological investigations will help to clarify routes of transmission on the other hand. Further studies will be necessary to learn more about the extent of A. suum as a causative agent of the VLM syndrome and the role of pigs and their manure as the main source of human Ascaris infections in Austria and other industrialized countries.

Background In Mexico, human toxocariasis is not subject to continuous epidemiological surveillance. However, some studies that report seroprevalence show a significant association between larva migrans (LM) and pediatric cases (OR 3.2; IC95 2.541-4.279). Data is scarce about infection in animal reservoirs, more specifically dogs, in which there are reports of a 12-18% positivity rate. As for the role of the environment there is evidence to support high contamination levels. Most symptomatic pediatric patients develop ocular presentations that can lead to permanent vision loss, and diagnosis becomes a challenge because serological markers and peripheral eosinophilia can be absent. Method A retrospective, transverse, descriptive study including 17 patients with diagnosis of toxocariasis according to electronic medical records. For categoric variables, frequencies and percentages were analyzed and for discrete variables median and ranges were calculated. Results Nine patients (52.9%) presented with ocular LM of which, 55.6% were female with a median age of 5 years at diagnosis (IQR=9). 44.4% came from the coastal state of Veracruz and 88.9% had close contact with either dogs or cats. Two patients presented with eosinophilia and only one had positive anti-Toxocara antibodies at 2.12 OD. Under suspicion of retinoblastoma, two patients underwent enucleation and diagnosis was made with pathology findings. Eight patients (47.1%) presented with visceral LM of which, 62.5% were female with a median age of 7.5 years at diagnosis (IQR=12). 62.5% of them had close contact with either dogs or cats. In this case, all patients had history of peripheral eosinophilia but it was only in 75% that it was corroborated during initial workup at our institution ranging between 500-9400 cells/mm3 and all of them had positive antibodies that ranged between 1.02-3.2 OD. Five patients received oral treatment with albendazole for 3-7 days. Conclusion Human toxocariasis is a neglected parasitic disease with scarce published data. Pediatric patients are an important vulnerable group specially for ocular presentations. The differential diagnosis of leukochoria should always include retinoblastoma, but as shown in this study, also ocular LM. As new approaches to global health move towards prevention, our study can set a precedent in order to standardize patient care and resource allocation.

Toxocariasis is a helminthozoonosis due to the infection of humans with larvae belonging to the Toxocara genus. Humans become infected as a result of accidental consumption of infected eggs containing third stage larvae (L3) nematodes from Toxocara canis or Toxocara cati species. Toxocariasis was recognized for the first time in the early 1950s, and the first cases of toxocariasis in Poland were described a few years later. Toxocariasis is clinically classified into several types: classic and incomplete visceral larva migrans (VLM) syndrome, ocular larva migrans (OLM) syndrome, neurological toxocariasis (NLM), covert toxocariasis and asymptomatic toxocariasis. In 1994-2005, 18,367 sera of people suspected of being infected with Toxocara were analysed, 1.8-76% had anti- Toxocara antibodies. In the period 1978-2009, 1,022 clinical cases of toxocariasis were recognized in Poland. In the opinion of the authors, in order to reduce the frequency of toxocariasis in human populations, some prophylaxis should undertaken, e.g. public education of zoonotic diseases, systematic control of animal, deworming of pets, cleaning pets' faeces by the owners.

Introduction: Toxocariasis is a parasitic disease that affects people all over the word. In case of infection, there is a significant increase in the number of leukocytes in the blood, which are a key element of the body's immune response. Among leukocytes, the number of eosinophils increases the most, and they play the main defensive role in the case of parasitic infections. As a consequence of parasitic stimulation a number of cytokines and immunoglobulins are produced, mainly IgG and IgE. Immunoglobulins are involved in recognizing foreign antigens, forming complexes with them, and then eliminating them from the body.Aim: The aim of the study was to assess the level of anti-Toxocariasis IgG, total protein including the γ fraction, IgG and IgE immunoglobulins and peripheral blood morphology (including leukocyte and eosinophil counts) in children with suspected Toxocara spp. infection.Material and methods: The study group included 31 children aged 2 to 17 years who tested positive for IgG antibodies against Toxocara canis/cati. Antibodies were obtained by ELISA. The concentration of IgE antibodies was assessed by electrochemiluminescence method and IgG antibodies by immunoturbidimetry. Blood count was determined using the Sysmex XT-4000i analyzer and capillary electrophoresis was used to separate proteins.Results: In children suspected of having toxocariasis, there was a statistically significant higher number of eosinophils and IgE concentrations compared to healthy individuals. Furthermore, the correlation assessment between the tested parameters revealed a statistically significant correlation in the study group between eosinophil count and IgG concentration, eosinophil count and total protein concentration, and eosinophil count and the gamma fraction protein concentration.Conclusions: Increased concentration of IgE immunoglobulin and eosinophils counts in the blood of patients may be an useful parameter in the diagnosis of toxocariasis in children. The demonstration of correlation in the study group between eosinophilia and IgG concentration, eosinophilia and total protein concentration, and eosinophilia and the gamma protein concentration confirms the possibility of measuring these parameters to determine infection of T. canis/cati in children.

Introduction: Toxocariasis, also known as Visceral Larva Migrans (VLM) syndrome, is a parasitic disease caused by the ascaris larva migrans of dogs and cats, especially Toxocaracanis. The eggs of this parasite enter the human body through contaminated food, water, and soil. Aim: To determine the prevalence of Toxocara spp. eggs in the soil of public parks in Ilam city, Iran. Materials and Methods: In this descriptive cross-sectional study, 40 soil samples (100 grams per sample from the depth of 3 to 5 cm) were randomly collected from 10 public parks of Ilam city in the summer season of 2018. After washing, grinding, and separating large particles from the samples, parasitic eggs were isolated using 150-micron filters and sucrose flotation method. The data was analysed using SPSS 20 software. Results: Five of ten parks (50) were contaminated with Toxocara spp. eggs. From 40 soil samples collected from the public parks, 16 (40) were contaminated with Toxocara spp. eggs. Most of the contaminated samples were collected from walking and flowering areas in all the parks. Microscopic studies showed an average of 1-4 Toxocara spp. eggs per microscopic field in each sample indicating 4 to16 eggs per 100 grams of soil in each contaminated park. Conclusion: Due to the high level of contamination with Toxocara spp, eggs in Ilam city parks, it is necessary to prevent dogs and cats from entering to lawns and playgrounds in public parks by fencing.

Ascariasis is frequently diagnosed in the dog population, and Toxocara canis is the main agent that causes larva migrans syndrome in humans. In big cities, the number of pets is constantly increasing, especially canids. In Romania, in addition to dogs with owners, a large number of dogs without owners are found in public green spaces. Timisoara is one of the largest cities in Romania, with a population of approximately 306.462 people. In the present study, the seroprevalence of anti-T. canis antibodies was investigated in different age groups using the ELISA method. The samples were taken and analyzed in a private laboratory. The results indicated a major deficiency in the control of ascariasis in animals. The overall seroprevalence recorded in 371 individuals who were referred to the laboratory during 2017-2020 was 22.64%. The elderly were the most affected (39.39%) and children were the least affected (7.4%) groups.

Precipitin reactions in monkeys ( Macaca sinica) experimentally infected with Toxocara canis and in children with visceral larva migrans syndrome

Toxocara spp. are parasitic nematodes responsible for human toxocariasis, a common zoonotic helminth infection. The five main features of human toxocariasis are the classical ocular toxocariasis and visceral larva migrans syndrome, followed by covert toxocariasis, common toxocariasis and neurotoxocariasis. The diagnosis of toxocariasis is feasible by considering clinical symptoms, anamnestic history and serology laboratory results; however, serological criteria cannot be used to distinguish active Toxocara infection from past exposure, which is an area of much discussion in clinical practice. In this context, we developed avidity tests (ELISA and immunoblotting) and evaluated their clinical usefulness in distinguishing past from active toxocariasis. Our study involved 46 patients divided into two groups: “active toxocariasis” (n = 14) and “chronic toxocariasis” (n = 32). According to the avidity indices obtained for both the chronic and active toxocariasis groups, we proposed two thresholds: first, an AI lower than 32% supports an active infection; secondly, a threshold above 42% can exclude an active infection. In order to use this assay in routine clinical practice, however, is still requires standardisation with regards to the method and threshold values, which can be established through studies involving larger populations.