Seropositivity for Toxocara spp. in Individuals with Animal Hoarding Disorder in Southern Brazil: An Alarm for Public Health.

PURPOSE: Animal hoarding has been associated with unhealthy human, animal and environmental conditions that predispose such individuals to serious life-threatening risks such as arson, malnutrition, cruelty and zoonosis. The study aimed to evaluate the presence of anti-Toxocara spp. antibodies among individuals with animal hoarding disorder in Curitiba, Brazil. METHODS: 65 residences with register of animal hoarder behavior were visited and 11 residences were included in the study, with a total of 19 individuals consenting participation. A short questionnaire was applied to gather information regarding hoarders and their dogs/cats, and serum samples were screened to detect antibodies (IgG) against antigens of Toxocara spp. RESULTS: Overall, 14/19 individuals (73.7%) presented anti-Toxocara spp. antibodies. In 8/11 (72.7%) households at least one person was seropositive. Seropositivity was higher among women (10/13; 76.9%) than men (4/6; 66.7%). A total of 442 dogs (14-30 dogs; average = 23.3 per household) and 31 cats (1-20 cats; average = 4.8 per household) were observed. To the authors' knowledge, this was the first study to survey occurrences of toxocariasis among animal hoarders. The high population densities of dogs observed during visits, in conjunction with absence of veterinary care and unsanitary conditions, may indicate that situations of high levels of animal infection and soil contamination were present. CONCLUSION: In summary, the seroprevalence observed in this study indicated that there was a high risk of Toxocara spp. infection among individuals with animal hoarding disorder. Provision of educational programs to reduce the risk of infection in this population is warranted.

Serosurvey of Toxoplasma gondii and Toxocara spp. co-infection in pregnant women in low-income areas of Brazil.

Introduction: Despite human toxoplasmosis and toxocariasis having been listed among the top six most neglected parasitic zoonoses worldwide, presenting similar associated risk factors and transmission routes, few studies have been conducted in pregnant women and the consequences of concurrent infection remain to be fully established. Accordingly, the present study has serologically assessed the co-infection and associated risk factors for Toxoplasma gondii and Toxocara spp. in pregnant women, assisted by the public Unified National Health System (SUS) in southeastern Brazil. Materials and Methods: Blood samples were collected and tested for IgG antibodies against Toxoplasma gondii by chemiluminescence immunoassay and against Toxocara spp. by enzyme-linked immunosorbent assay (ELISA). An epidemiological questionnaire was applied to gather socioeconomic information to assess the risk factors associated with seropositivity to toxocariasis/toxoplasmosis by univariate analysis followed by logistic regression. Results: Overall, seropositivity was 69/280 (24.6, 95% CI: 19.96-30.01) for T. gondii and 56/280 (20.0, 95% CI: 15.73-25.08) for Toxocara spp. Co-infection was observed in 25/280 (8.9, 95% CI: 6.12-12.85) pregnant women, with increased odds (OR: 3.3, CI 95%: 1.77-6.14, p = 0.0002). Logistic regression revealed that a higher educational level (high school or college) significantly reduced the likelihood of co-infection seropositivity, owning cats increased the odds of toxocariasis, and older pregnant women presented significantly higher T. gondii seropositivity. Conclusion: Co-infection herein highlights the importance of educational programs in the prevention of toxocariasis and toxoplasmosis in pregnant women and other high-risk populations.

Risk factors for toxocariasis during incarceration: the One Health intervention approach.

Despite potential exposure to soil-transmitted helminths, especially when stray dogs and cats are present, toxocariasis in inmate populations remains to be established. Accordingly, the present study assessed the seroprevalence and associated risk factors of toxocariasis at the Women's State Penitentiary of Parana, Brazil. A total of 234/370 (63.2%; 95% CI 58.2-68.0) women inmates and 28/87 (32.2%; 95% CI 23.3-42.6) correctional officers were seropositive for anti-Toxocara spp. IgG by ELISA, with inmates 2.62-fold more likely positive (p = 0.00000026). The univariate model has identified that non-white (OR = 1.58, p = 0.047) and older than 39 years (OR = 1.28, p = 0.032) inmates were associated with mild but significant odds for seropositivity. Elementary or higher educational level was considered a protective factor for seropositivity. The presence of Toxocara spp. eggs was observed in 10/15 (66.7%) collected soil samples by centrifuge-flotation in Zinc Sulfate, and molecular analysis by PCR identified only Toxocara cati in these eggs. An intervention program was established with regular trap-neuter-release, with gradual removal for adoption (donation campaigns), treatment, and euthanasia when necessary (particularly due to advanced sporotrichosis). In addition, an educational awareness agenda was proposed, aiming to reduce soil contamination and accidental intake by the incarcerated population. A total of 40 feral cats were trapped, 20 males and 20 females, mostly adults. After trapping, 36 cats were neutered, treated, and microchipped in the Veterinary Teaching Hospital (VTH) at the Federal University of Paraná. Five trapped feral cats were euthanized, four diagnosed with advanced sporotrichosis, and one already neutered cat (not herein) with complications due to feline immunodeficiency virus (FIV). Female inmates presented higher seroprevalence for Toxocara spp. antibodies when compared to correctional officers, significantly associated with age, self-declared ethnicity (non-white), and lack of formal education. Despite the non-natural scenario of a state penitentiary, the One Health approach of Toxocara spp. has highlighted the interdisciplinary nature of the study and its relevance in understanding the complex interactions between human, animal, and environmental factors, particularly impacting female inmates. Further studies should establish the rate of inmate infection over time while deprived of liberty.

One health approach to toxocariasis in quilombola communities of southern Brazil.

BACKGROUND: Toxocariasis has been listed among the most neglected parasitic diseases worldwide, with approximately one fifth of the global population exposed, particularly those living under poverty. In Brazil, communities of descendants of enslaved blacks (quilombola) have historically had some of the highest rates of vulnerability and poverty, characterized by lack of health assistance, poor quality of life, and nutritional insecurity. METHODS: A cross-sectional sampling of quilombola individuals living in four communities of southern Brazil, as well as their dogs and the soil, was carried out from December 2021 to March 2022. Sociodemographic and other information such as water source, alimentary habits, and dog and cat ownership were gathered using a semi-structured questionnaire for assessing toxocariasis risk factors. Human serum samples were tested by ELISA for anti-Toxocara spp. IgG antibody detection was carried out on dog feces and hair, and soil samples were surveyed for presence of Toxocara spp. eggs. RESULTS: Overall, 172/208 individuals (82.7%, 95% CI = 77.0-87.2) were seropositive, the highest seroprevalence rate to date in Brazil. Male gender (P = 0.029), educational level (P = 0.026), and drinking water source (P = 0.043) were associated with seropositivity by univariate analysis. Final logistic regression revealed increased odds (P = 0.017, OR = 7.6, 95% CI = 1.5-42.7) to have seropositivity in individuals > 50 years old (< 10 years old). As expected, individuals with soil contact were more likely seropositive (P = 0.038, OR = 4.4, 95% CI = 1.1-18.8). Although retrieved in only 5/96 (5.2%) dog feces, Toxocara spp. eggs were found in 18/60 (30.0%) soil samples. CONCLUSIONS: The high vulnerability and seroprevalence observed in quilombola communities clearly demand a One Health approach for detection, monitoring, and prevention of infection by Toxocara spp. in both human and dog populations.

One health approach to toxocariasis in Brazilian indigenous populations, their dogs, and soil contamination.

Introduction: Although socioeconomic vulnerability and lifestyle factors may contribute to the transmission of Toxocara spp., no study has investigated indigenous populations in Brazil using the One Health approach. Methods: Accordingly, this study assessed anti-Toxocara spp. antibodies in Brazilian indigenous people and healthcare professionals by enzyme-linked immunosorbent assay. Presence of Toxocara spp. eggs (feces and hair) in dogs as definitive hosts and in soil samples of the indigenous communities were also recovered and molecularly investigated. Results: Overall, 342/463 (73.9%) indigenous individuals and 46/147 (31.3%) non-indigenous healthcare professionals were seropositive for Toxocara spp. In addition, T. canis eggs were retrieved from 9/194 (4.6%) dog fecal samples and 4/204 (2.0%) dog hair samples, mainly from the Paraná State communities (3/42; 7.1%). Soil contamination was observed only in the Paraná State communities (36/90; 40.0%), with the molecular detection of T. canis. River water consumption was also associated with indigenous seropositivity (Odds ratio, 11.4). Discussion: Indigenous individuals in Paraná State communities were 2.72-fold more likely to be seropositive than those in São Paulo State, likely due to a lack of sanitary infrastructure. In this scenario, a primarily soil-transmitted disease may also have become waterborne, with embryonated eggs probably spread to water supplies by rain. Full-time healthcare professionals in daily contact with indigenous communities were 9.2-fold more likely to be seropositive than professionals who visited sporadically, suggesting exposure to Toxocara spp. during their work and raising health concerns. In addition, the findings herein showed a significantly higher seroprevalence in indigenous people than in healthcare workers (χ2 = 85.5; p < 0.0001), likely due to overtime exposure to Toxocara spp. In conclusion, Brazilian indigenous communities are highly exposed to toxocariasis, with poor infrastructure and contact with contaminated river water as associated risk factors and a higher risk of infection in healthcare professionals working full-time in these communities.

One Health Approach in Serosurvey of Toxoplasma gondii in Former Black Slave (Quilombola) Communities in Southern Brazil and Among Their Dogs.

Brazilian quilombos are rural semi-isolated remnant communities of former black slaves and their descendants who traditionally maintained themselves through archaic subsistence livestock and agriculture practices and historically lacked specific public health policies. Although such individuals and their dogs may be exposed to zoonotic pathogens such as Toxoplasma gondii, no study to date has assessed these human-animal populations together. Populations in four different Brazilian quilombos in southern Brazil were evaluated. Overall, 93/208 people (44.7%) and 63/100 dogs (63.0%) were seropositive for IgG anti-T. gondii antibodies by indirect immunofluorescent antibody test (IFAT), 4/208 (1.9%) human samples seropositive for IgM anti-T. gondii antibodies, with a human-dog seropositivity ratio for IgG of 0.71. Quilombola individuals ingesting game meat were 2.43-fold more likely (95% CI: 1.05-5.9) to be seropositive. No risk factors were associated with seropositivity among dogs, thus suggesting that their exposure to T. gondii was random. Surprisingly, our research group had previously found an inverted human-dog ratio for T. gondii seropositivity of 2.54 in the urban area of a nearby major city. Because consumption of raw/undercooked game meat by quilombola individuals may have contributed to higher exposure, higher overall seroprevalence among dogs may have also indicated interaction with wildlife. Although these dogs may hunt wildlife without their owners' awareness, the higher dog seropositivity may also be related to feeding from discarded food in the community or backyard livestock animals and drinking surface water contaminated with oocysts. Thus, wildlife cannot be singled out as the reason, and future studies should consider sampling water, soil, wildlife, and livestock tissues, to fully establish the source of infection in dogs herein.

Toxoplasma gondii exposure in Brazilian indigenous populations, their dogs, environment, and healthcare professionals.

Although Toxoplasma gondii exposure has been reported in indigenous populations worldwide, a One Health approach has not been applied to date. This study concurrently assessed T. gondii exposure in indigenous populations, and their dogs, environment, and indigenous or non-indigenous healthcare professionals (HPs). Human and dog serum samples from 9 indigenous communities in Brazil were assessed by indirect immunofluorescence antibody test for anti-T. gondii antibodies. Soil samples (30 per community) were processed with PCR to amplify T. gondii DNA. Associated risk factors and seroprevalence were analyzed using logistic regression models. Human seropositivity and type of water source were assessed by generalized linear mixed model (GLMM) with binomial error distribution, and game meat consumption with chi-squared test. Overall, 225/463 (49%) indigenous persons were seropositive for anti-T. gondii antibodies. Of all the HPs, 67/168 (40%) were positive, and included 54/147 (37%) positive non-indigenous HPs. Indigenous persons more likely to be seropositive compared with non-indigenous HPs (OR: 1.63; 95% CI: 1.11-2.39). A total of 97/253 (38%) dogs were seropositive and highly associated with seropositive owners (p < 0.001). Based on univariate analysis for indigenous individuals, state location of community (p < 0.001), ethnicity (p < 0.001), consumption of game meat (p < 0.001), type of water source (p < 0.001), and educational level (p = 0.026) were associated with seropositivity. Logistic regression showed that indigenous seropositivity was associated with eating game meat (p = 0.002), drinking water from rivers (p < 0.001), and inversely proportional to the educational level. According to univariate analysis for non-indigenous HP, age (p = 0.005), frequency of visits to the indigenous populations (p < 0.001), consumption of water at the indigenous communities (p < 0.001), and ingestion of raw meat (p = 0.023) were associated with T. gondii seropositivity. Logistic regression revealed living outdoors (p = 0.042), habit of hunting (p = 0.008), and drinking river water (p = 0.007) as risk factors associated to seropositivity in dogs. In addition, indigenous communities lacking water treatment had higher seroprevalence for all groups including indigenous persons (GLMM; z = -7.153; p < 0.001), their dogs (GLMM; z = -2.405; p = 0.0162), and all HPs (GLMM; z = -2.420; p = 0.0155). Human seropositivity was associated with that of their dogs (p < 0.001). A single soil sample, out of 270 (0.37%), was positive for T. gondii by PCR. Our results indicate water source is a risk for human and dog toxoplasmosis in indigenous communities; both share similar exposure. Moreover, quality water access was shown to be crucial to prevent toxoplasmosis in both total and non-indigenous HPs who work in these indigenous communities.

Spatial Owner-Dog Seroprevalence of Leptospira spp. Antibodies in Oceanic Islands and Costal Mainland of Southern Brazil.

Leptospirosis has been described as a disease neglected worldwide. Affecting humans and animals, the disease is often related to poor environmental conditions such as lack of sanitation and presence of synanthropic rodents. Despite being considered as a One Health issue, no study has focused on comparing owner-dog seroprevalence between islands and seashore mainland. Accordingly, the present study assessed anti-Leptospira spp. antibodies by applying microscopic agglutination test (MAT) methods to Leptospira and assessing associated risk factors via univariate and multivariate logistic regression analysis of owners and their dogs in islands and seashore mainland of southern Brazil. No anti-Leptospira spp. Seropositivity was found in 330 owner serum samples, while dogs presented an overall seroprevalence of 5.9%. All seropositive dogs reacted to serogroups of Leptospira interrogans, including 66.7% of Pyrogenes, 44.4% Canicola, 22.2% Icterohaemorrhagiae, 16.7% Australis; six reacted to more than one serogroup. No association was found among seropositivity and epidemiological variables, except that neighborhood dogs were less likely to be seropositive. Although no seropositivity was observed in owners, seropositivity in dogs had the potential to indicate such species as being sentinels for environmental exposure and potential human risk of infection.

Seroprevalence and associated risk factors of strongyloidiasis in indigenous communities and healthcare professionals from Brazil.

Strongyloides stercoralis, a pathogenic roundworm, is considered endemic in several tropical and subtropical areas worldwide. Indigenous populations have the highest soil-transmitted helminthiases-related mortality rates, but the prevalence and risk factors associated with S. stercoralis in Brazilian indigenous populations have not been established. Thus, the present study aimed to assess the seroprevalence and associated risk factors for S. stercoralis in indigenous communities and the healthcare professionals serving them in Brazil. Indigenous populations living in nine communities and healthcare professionals were tested for anti- S. stercoralis antibodies by ELISA. A questionnaire was used to assess socio-epidemiological information. Associated risk factors for seropositivity were tested by chi-square or Fisher's exact tests, using univariate analyses and multivariate logistic regression. Overall, 174/463 (37.6%; CI 95%: 33.3-42.1) indigenous persons and 77/147 (52.4%; 95% CI: 44.3-60.3) healthcare professionals were seropositive for anti- S. stercoralis antibodies. Seropositivity among the two groups was statistically significant (p = 0.0016; OR = 0.547; 95% CI: 0.376-0.796) and revealed that healthcare professionals were 1.83 times more likely to be seropositive. The multivariate analysis showed that being male or being adult were also risk factors, while having a septic tank as a sanitary facility represented a protective factor for S. stercoralis exposure in indigenous persons. None of the variables evaluated were associated with S. stercoralis exposure in the professional group. The study herein has reported a high seroprevalence to Strongyloides stercoralis in indigenous communities of Brazil and healthcare professionals, warning for potential public health concerns of strongyloidiasis in such populations.

Seropositivity of Anti-Toxoplasma gondii Antibodies in Owners and Their Dogs Living on Island and Mainland Seashore Areas of Southern Brazil.

Although toxoplasmosis has been considered among the most neglected zoonoses worldwide, no study has focused on the frequency and associated risk factors of owners and their dogs living on an island and mainland seashore areas. Accordingly, anti-Toxoplasma gondii IgG antibodies were screened by indirect fluorescent antibody test (IFAT) in owners and dogs from three oceanic islands and two nearby mainland harbor areas, with associated risk factors for toxoplasmosis assessed by univariable and multivariable logistic regression models. Overall, anti-T. gondii seropositivity was observed in 59/328 (18.0%) owners and 66/283 (23.3%) dogs, with no statistical difference between owners (p = 0.360) and dogs (p = 0.655) from islands and mainland areas. Consumption of local water springs (p = 0.016; OR = 2.11) was an associated risk factor for T. gondii seropositivity, and owners with the habit of spring water intake were twice more likely seropositive (p = 0.014; OR = 2.14). Presence of anti-T. gondii antibodies in dogs was associated with seropositive owners (p = 0.008; OR = 2.81), household consumption of beef meat (p = 0.042; OR = 1.7) and chicken (p = 0.026; OR = 2.9). Despite being lower than the worldwide prevalence, toxoplasmosis seropositivity in owners and their dogs in southern Brazil was influenced by the positive owner, water source, and meat consumption, and not by inhabiting islands or seashore mainland areas, presence of dogs, cats, or both. In addition, drinking water quality should always be considered a critical risk factor for toxoplasmosis on islands.

Serosurvey of anti-Toxocara canis antibodies in people experiencing homelessness and shelter workers from São Paulo, Brazil.

BACKGROUND: Despite being one of the most prevalent helminth parasitic zoonoses worldwide and particularly in socioeconomically vulnerable populations, toxocariasis remains to be fully investigated in persons experiencing homelessness. Accordingly, the present study has aimed to assess the seroprevalence and associated risk factors of Toxocara spp. exposure in persons experiencing homelessness and shelter workers from a day-shelter in São Paulo city, Brazil. METHODS: Anti-Toxocara IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis. RESULTS: Overall, anti-Toxocara IgG antibodies were detected in 89/194 (45.9%, 95% CI: 39.0-52.9%) persons experiencing homelessness, twice as high (OR = 2.2; 95% CI = 1.245-3.873; P = 0.0089) than the frequency of 22/79 (27.8%, 95% CI: 19.2-38.6) in shelter workers. College education was the only protective factor for Toxocara spp. exposure (OR: 0.23; P = 0.018) revealed by logistic regression. CONCLUSIONS: Although indicating a multifactorial origin of toxocariasis, the present study has assessed a highly vulnerable population with high disease risks and premature death. Thus, the living conditions of the homeless population have influenced the high prevalence of anti-Toxocara antibodies verified here compared with domiciled shelter workers. Despite being less exposed, shelter and other outdoor workers may present an occupational risk to toxocariasis. Future studies should establish whether such environmental exposure might occur in persons experiencing homelessness in other regions worldwide.

Dog and Cat Contact as Risk Factor for Human Toxocariasis: Systematic Review and Meta-Analysis.

Toxocariasis, a neglected parasitic zoonosis with worldwide distribution, has been reportedly associated to different risk factors in several epidemiological and meta-analysis studies. However, dog and cat contact (environmental and animal exposure) as isolated associated risk factor for children and adults remains to be fully established. Accordingly, the present meta-analysis has aimed to directly assess dog and cat contact for toxocariasis seropositivity in under-18 and adult persons, using a survey strategy of PubMed/Medline, Embase, Scopus and Scielo Databases, from January 2009 to December 2021. A meta-analysis model of random effects was applied to estimate odds ratio (OR) with 95% Confidence Interval (CI). The statistical heterogeneity was evaluated by the Cochran Q-Test and I2 values. A total of 41 transversal studies (n = 20.515 individuals) from different geographic regions (classified by the World Health Organization) were included herein. In overall, 1,882/13,496 (13.95%; 95% IC = 13.4-14.5) youngers and 513/7.019 (7.3%; 95% CI = 6.7-7.9) adults in contact with dogs or cats were serologically reagent for anti-Toxocara antibodies. Association of dog and cat contact was observed only in youngers, with both dogs (OR = 1.53; p < 0.0001) and cats (OR = 1.64; p = 0.0001). In addition, association of dog and contact and serology was statistically significant in populations of Americas (OR = 1.37; 95% CI = 1.1-1.7), Middle East (OR = 2.9; 95% CI = 1.6-5.1) and West Pacific (OR = 1.6; 95% IC = 1.3-1.9). In conclusion, contact with dogs and cats, particularly by younger individuals and in regions such as Americas, Middle East, and West Pacific, should be always a public health concern for toxocariasis. Moreover, dogs and cats should be periodically dewormed, washed and hair cleaned prior to contact with youngers. Finally, robust statistical results herein may serve as basis for future strategies and preventive measures for safer dog and cat contact.

One Health approach on human seroprevalence of anti-Toxocara antibodies, Toxocara spp. eggs in dogs and sand samples between seashore mainland and island areas of southern Brazil.

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.

Serosurvey of anti-Toxocara antibodies and risk factors in adolescent and adult pregnant women of southeastern Brazil.

Toxocariasis is worldwide endemic parasitic anthropozoonosis with high risk to those in in vulnerable populations and particularly during pregnancy and childhood. Although the prevalence of anti-Toxocara spp. antibodies has been extensively studied, risk factors of pregnant women of different ages remains to be established. This study was designed to i) assess the presence of anti-Toxocara spp. antibodies in pregnant women that presented to the public health system in a city of southeastern Brazil, and ii) determine the risk factors for toxocariasis in adolescent and adult pregnant women. This cross-sectional study included 280 pregnant women (71 aged up to and including 17 years [adolescents] and 209 aged 18 years and older [adults]). Pregnant women voluntarily agreed to complete a socioeconomic questionnaire and provide serum samples. Anti-Toxocara IgG antibodies were screened by Enzyme-Linked Immunosorbent Assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis. Overall, 20.7% of pregnant women were seropositive (33.8% of adolescents and 16.3% of adults). Prevalence in pregnant adolescents was 2.6-fold higher than in adults (Odds ration [OR]: 2.63; 95% CI: 1.42-4.86, p = 0.003). Multivariate analysis revealed that contact with soil (p = 0.01; OR = 4.76) and being in the first trimester of pregnancy (p = 0.03; OR = 0.17) had significantly greater risk of toxocariasis for adolescents, and attainment of elementary through middle school education level (p = 0.05; OR = 8.33) was a risk factor in adult pregnant women. Toxocariasis is likely underreported and neglected in adolescent pregnant women; this age group should always be monitored for toxocariasis and correspondent clinical signs, particularly at late pregnancy.

The Role of Nile Tilapia (Oreochromis niloticus) in the Life Cycle of Toxocara spp.

The present study aimed to experimentally assess Nile tilapia as potential paratenic host of Toxocara spp. A total of 15 Nile tilapia (Oreochromis niloticus) were fed with 300 embryonated Toxocara canis eggs by oral gavage, while five others of the control group received distilled water. The fish were individually analyzed at 16, 24, 48, 72, and 240 h after inoculation. Water contamination was assessed, and tissue migration by liver, gastrointestinal tract (GIT), eyes, and central nervous system. A murine model was used as the paratenic host for egg infectivity assessment. Eggs and larvae were found in plastic tank water and fish GIT, ranging from 23 to 86% per fish. Eggs and larvae were recovered from the tank water (76.3%) and fish GIT (23.7%). The counting of eggs and larvae observed was negatively correlated with number of eggs and larvae in the water tank (rho = -0.698, p = 0.003). Shedding of embryonated eggs was first detected at 16 and up to 240 h, with significant egg and larvae yield decrease on water-shedding (p = 0.001) and in the GIT (p = 0.007). Although no T. canis larva was recovered in fish tissues, egg infectivity after fish GIT transit was experimentally confirmed by mice assessment. In conclusion, despite shedding viable embryonated eggs through the gastrointestinal tract, tilapias may not play a role as a suitable paratenic hosts for Toxocara spp., posing low risk of zoonotic transmission by fish meat consumption.

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

BACKGROUND: Toxocariasis, caused by a nematode species of the genus Toxocara, has been described as one of the most prevalent zoonotic helminthiases worldwide. Human transmission may occur by ingesting Toxocara spp. larvae from raw or undercooked meat or organs; however, no comprehensive serosurvey study has been conducted to date investigating the role of cattle as paratenic hosts. The aim of the study reported here was to assess the prevalence of anti-Toxocara spp. antibodies and associated risk factors in bovines from two slaughterhouses located in Presidente Prudente, southeastern Brazil. METHODS: Blood samples were collected and tested by indirect enzyme-linked immunosorbent assay (ELISA). Cattle farmers voluntarily responded to an epidemiologic questionnaire. RESULTS: Overall, 213 of the 553 (38.5%) bovine samples were assessed as seropositive for anti-Toxocara spp. antibodies by indirect ELISA. Multivariate analysis revealed that the source of beef cattle and the presence of dogs or cats at the farm were associated with seropositivity. The use of feedlot systems was associated with lower likelihood of seropositivity. CONCLUSIONS: These results indicate a high level of anti-Toxocara seropositivity in slaughterhouse cattle, with potentially contaminated meat posing an infection risk to humans. In addition, the presence of dogs and cats where the slaughtered beef cattle were raised was statistically associated with bovine seropositivity, probably due to the overlapping environment at the farm and the lack of pet deworming. The use of feedlot systems was a protective factor likely due to the absence of dog and cat contact, elevated feeding troughs that avoid contact with contaminated soil or grass, and younger age at slaughter of feedlot cattle. In summary, bovines may be used as environmental sentinels of Toxocara spp. contamination, and high seropositivity of slaughterhouse cattle may indicate a potential risk of human toxocariasis through the ingestion of raw or undercooked contaminated meat.

Dispersion and infectivity of Toxocara canis eggs after passage through chicken intestine.

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.

Frequency of anti-Toxocara antibodies in broiler chickens in southern Brazil / Frequência de anticorpos anti-Toxocara em frangos de corte no Sul do Brasil

Abstract 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.

Frequency of anti-Toxocara antibodies in broiler chickens in southern Brazil.

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.

Protective and risk factors associated with the presence of Toxocara spp. eggs in dog hair.

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 300µm, 212µm, and 38µm. 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.