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Toxocariasis, caused by Toxocara spp. nematodes, is among the top 5 neglected parasitic diseases worldwide; however, no comprehensive study to date has serologically compared infections in people and their dogs and environmentally contaminated soil or sand of mainland and island locations. Accordingly, this study aimed to assess the seroprevalence of anti-Toxocara antibodies in traditional human seashore populations, the presence of eggs in dogs' feces and hair, and the presence of eggs in environmental samples from islands compared to the adjacent mainland of southern Brazil. Overall, 212/328 (64.6%) people were positive for Toxocara spp. antibodies, including 125/190 (65.8%) island and 87/138 (63.0%) mainland residents. For dog samples, 12/115 (10.43%) were positive for the presence of Toxocara spp. eggs, all from dogs living in islands, and 22/104 (21.15%) dog hair samples contained eggs of Toxocara spp. Environmental contamination with Toxocara spp. eggs was observed in 50/130 (38.46%) samples from all sampled sites. No significant association was found between risk factors (age, sex, educational level, monthly income, owning dogs or cats, ingestion of treated water, and consumption of raw or uncooked meat) and Toxocara spp. seropositivity. The present study is the first concurrent report on people, their dogs, and environmental contamination of Toxocara spp. The high prevalence we observed in the seashore populations of both in island and mainland areas may be caused by exposure to contaminated sand and climatic factors favoring frequent exposure to Toxocara spp. In conclusion, seashore lifestyle and living conditions of both island and mainland areas may have predisposed higher contact with infected pets and contaminated soil, favoring the high prevalence of toxocariasis., Highlights • The first report with a One Health approach towards toxocariasis, with concurrent assessment of human, dog, and soil samples. • The first comparison of adjacent mainland and island areas for human toxocariasis. • Report of the highest Toxocara spp. seropositivity in children and teens to date in Brazil.

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.

Toxocariasis is an important, but neglected, worldwide zoonosis. It is considered a primarily soil-transmitted disease, but food-borne transmission has been associated with the consumption either of raw or undercooked meat of paratenic hosts, including birds. Despite the number of experimental studies carried out to evaluate the behavior of Toxocara spp. larvae in birds, their role in the dispersion of eggs into the environment remains unclear. Thus, this study aimed to evaluate the potential of broiler chickens to release Toxocara canis eggs into the environment, and the infectivity of eggs after passage through the intestine. Forty commercial broiler chickens, aged 60 days, were randomly distributed into three groups. Groups 1 (n = 16) and 2 (n = 16) were orally infected with 5000 embryonated and 5000 unembryonated T. canis eggs, respectively. Group 3 (n = 8) served as a control. Following infection, fecal samples from each chicken were examined using a centrifuge-sedimentation technique. At 24-h, 72-h, and 7-day post-infection (PI), four chickens each from the G1 and G2 groups, and two from the G3 group were killed. After euthanasia, the intestinal content and liver were collected for recovery of T. canis larvae. Results revealed that broiler chickens have the potential to disperse both embryonated and unembryonated T. canis eggs, following 2- to 6-h PI. In addition, the eggs shed into the feces of the G2 birds, after incubation in laboratorial conditions, were infective when they were tested in a bioassay using mice. In conclusion, broiler chickens have the potential of dispersing Toxocara spp. eggs into the environment and the eggs passed through the intestine are infective after being incubated in experimental conditions.

Toxocariasis is one of the most prevalent parasitic zoonoses in the world. The disease is principally caused by the nematode Toxocara canis , whose definitive host is the dog. The transmission of toxocariasis to humans is mainly caused by accidental ingestion of embryonated eggs of the parasite, present in the soil. Studies have shown that dog hair has the capacity to harbor eggs of the parasite and represents a risk for transmission of the zoonosis. The objective of the present study was to evaluate the frequency and factors associated with the contamination of dog hair by Toxocara spp. of animals attended and/or abandoned at a Veterinary-Teaching Hospital in Southeast Brazil. The hair samples were collected from the perineal region, and upper and lower tail regions. For analysis of the samples and recovery of Toxocara spp., the material was washed in Tween 20 and then filtered through sieves of 300 μm, 212 μm, and 38 μm. Hair samples from 165 dogs were analyzed. Of the analyzed samples, 59 (35.8%) were from puppies and 106 (64.2%) from adult animals. In the sample evaluation, 6.7% of the dogs (11/165) were contaminated, with a mean of 12.2 eggs per animal (1–70 eggs/animal) and 57.5 eggs/gram of hair. All the recovered eggs were not embryonated. There was an influence of age (puppies), breed (without defined breed), and origin (stray) of the dogs. On the other hand, deworming was a protective factor. Our results show that the risk of transmission of toxocariasis by direct contact, mainly in well-cared dogs, is low. Thus, prophylactic anthelmintic treatment and correct care regarding the hygiene of animals, especially puppies, should be recommended to reduce any risk of transmission of toxocariasis.

The aim of this study was to evaluate the presence of anti-Toxocara antibodies in naturally infected broiler chickens (n = 189) from the state of Paraná, southern Brazil. The chickens were reared in a semi-intensive system by small family farmers (n = 7). An enzyme-linked immunosorbent assay (ELISA) was performed to detect the presence of anti- Toxocara spp. IgY after serum adsorption with Ascaridia galli antigens. An overall seroprevalence of 67.7% (128/189; 95% CI = 61.1-74.4) was observed. The frequency of positive animals by farm ranged from 29.6% to 100%. The optical density and reactivity index values observed in ELISA test indicated the possible chronicity of infection of the evaluated chickens. Associations between the presence of antibodies and the area where the chickens were reared (p = 0.382) or the population density of dogs on the farm (p = 0.785) were not observed. This study shows a high prevalence of Toxocara spp. antibodies in broiler chickens reared in semi-intensive systems and provides evidence that chickens are a good indicator of environmental contamination by larva migrans agents. Further studies are necessary to assess the risk factors associated with poultry infection and the likelihood of toxocariasis transmission to humans via the ingestion of free-range chicken meat. Resumo A finalidade do presente estudo foi avaliar a presença de anticorpos anti- Toxocara, em frangos de corte naturalmente infectados (n = 189), no Norte do Paraná, Sul do Brasil. Os frangos foram criados em sistema semi-intensivo, em pequenas propriedades rurais (n = 7). Os testes sorológicos foram realizados pela técnica de ELISA, para detecção de anticorpos IgY (IgG), com pré-adsorção do soro com antígenos de Ascaridia galli. Foi observada uma prevalência de 67,7% (128/189; IC 95% = 61,1-74,4). A frequência de animais soropositivos por propriedade variou de 29,6% a 100%. Os valores da Densidade Ótica e do Índice de Reatividade observados no teste de ELISA indicaram uma possível cronicidade de infecção dos frangos avaliados. Não foi observada correlação entre a positividade dos animais, quando comparada a área (p = 0,382) e a densidade populacional de cães por propriedade (p = 0,785). O presente estudo verificou uma alta prevalência de anticorpos anti-Toxocara em frangos de corte criados em sistema semi-intensivo e oferece dados que apontam esses animais como bons indicadores de contaminação ambiental por agentes de larva migrans . Estudos futuros são necessários para avaliar os fatores de risco associados e a possibilidade da transmissão de toxocaríase ao ser humano pela ingestão de carne de frango.

Toxocariasis is a geohelminth zoonosis with worldwide distribution, mainly transmitted through the ingestion of embryonated eggs of nematodes of the Toxocara genus. The disease can also be transmitted to humans as a result of eating raw or undercooked meat of paratenic hosts, such as chickens. Here, we standardized an enzyme-linked immunosorbent assay (ELISA) for evaluating experimentally the kinetic and avidity index (AI) of IgY in broiler chickens infected with different doses of Toxocara canis eggs (G1:100; G2: 1000; and G3: 5000; n = 12 per group). The test showed 91.7% sensitivity (CI 95%: 77.5–98.3) and 100% specificity (CI 95%: 92.6–100), and highest efficiency (97.0%) at 60 days post infection. Infection was characterized by the presence of high avidity antibodies in the chronic phase. Our results support that the ELISA can be a highly useful tool for the detection of anti- Toxocara antibodies in chickens.

O objetivo do estudo foi avaliar o limite de detecção de larvas de Toxocara canis em leite bovino comercial contaminado experimentalmente, a partir de uma técnica de centrifugo-sedimentação. Primeiramente, amostras de leite bovino comercial (integral e desnatado) foram contaminadas com 50 larvas de T. canis, para avaliação da interferência da gordura sobre a recuperação das larvas. Em uma segunda etapa, foi avaliada a ação de formalina 10% (100 ?L), éter (100 ?L) e combinação das soluções. A terceira etapa consistiu da verificação do limite de detecção de larvas, com uso da melhor solução desengordurante (etapa 2), em amostras de leite (1,0 mL) contendo 1; 5; 10; 25 e 50 larvas. Para cada análise de detecção do leite (1,0 mL), foram realizadas 15 repetições. Foi observado que o percentual de recuperação de larvas no leite desnatado foi significativamente maior (p= 0,0031) que o observado no leite integral. Na comparação das soluções, não houve diferença significativa (p= 0,5681) no percentual de larvas recuperadas. Entretanto, houve uma maior recuperação quando do emprego da combinação de formol-éter (73,1%) em relação ao éter (71,9%), ao formol (67,6%) e ao leite integral puro (70,0%). Em relação ao limite de detecção, com uso de formalina-éter, todas as alíquotas apresentaram resultado positivo (mínimo de 62,7% de larvas recuperadas), para as amostras com 5, 10, 25 e 50 larvas. Nas amostras contaminadas com uma larva, 66,7% das alíquotas foram positivas. A técnica apresentada poderá servir para recuperação de larvas de Toxocara spp. em amostras de leite de várias espécies animais, contaminados naturalmente ou experimentalmente.