Toxocariasis in waste pickers: a case control seroprevalence study

Seroprevalence of human toxocariasis in Latin America and the Caribbean: a systematic review and meta-analysis

Introduction

The current study aimed to quantitatively synthesize available evidence regarding the seroprevalence of human toxocariasis in Latin America and the Caribbean.

Methods

A systematic research involving six electronic databases was conducted using a research strategy that combined MeSH terms with free terms. Article selection and information extraction were performed using a double and independent approach. The Newcastle-Ottawa tool was used to assess the risk of bias in the included articles. The meta-analysis used the random-effects approach, with subgroup analysis and sensitivity analysis for risk of bias also being performed.

Results

We included 101 articles with a total of 31,123 participants. The studies were conducted between 1990 and 2022, with Brazil accounting for the largest number of studies (n = 37). The overall seroprevalence of human toxocariasis was 31.0% (95% CI: 27.0-35.0%, I2 = 99%). The prevalence of the main characteristics observed in seropositive patients were as follows: ocular toxocariasis (30.0%), asymptomatic (26.0%), and presence of dogs at home (68.0%). In addition, the seroprevalence was lower in studies including only adults than in those including children or both. In contrast, no differences in seroprevalences were found between studies conducted in the community and hospital.

Conclusion

The overall seroprevalence of human toxocariasis in Latin America and the Caribbean was high. Notably, our findings showed that the seroprevalence was increased among populations who kept a dog at home but was decreased in populations comprising only adults. Our findings can be used to establish epidemiological surveillance strategies for the prevention and early identification of toxocariasis.

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.

A systematic review on informal waste picking: Occupational hazards and health outcomes

Informal waste picking is a common way for people to earn an income, especially in low-income countries; unfortunately, there are various occupational hazards and health outcomes associated with waste picking. This study focused on comprehensively identifying and exploring occupational hazards and health outcomes associated with informal waste picking. A systematic review of available relevant and peer-reviewed literature was completed to exhaustively analyze the full scope of these hazards and outcomes associated with informal waste picking; 58 papers were included. The results from this study provided insight and information related to the most common occupational hazards and negative health outcomes associated with informal waste pickers outlined in available literature. The most common reported occupational hazards were physical (77.6%), social (70.7%), biological (65.5%), chemical and safety (53.4%), ergonomic (34.5%) and mechanic (25.9%). Health outcomes appeared to include epidermal (50.0%), communicable disease (46.6%), musculoskeletal (44.8%), respiratory disease (41.4%), non-communicable diseases (39.7%), physiological (34.5%), gastrointestinal (31.0%) and waterborne diseases (17.2%). Physical hazards were often associated with slips, trips, and falls, which makes sense because of the unstable environment where waste pickers work. Health outcomes related to these hazards included bruises, cuts, and lacerations. This information also aligns with health outcomes, as epidermal outcomes were most reported in waste pickers (50.0% of data). It is clear that moving forward, additional research related to these occupational hazards and health outcomes associated with informal waste picking is needed to help create change in this affected population, as well as finding effective solutions to mitigate these hazards and outcomes. These hazards can be mitigated by simple, common control measures, like providing safety equipment, reducing hazards from the outside environment (e.g., less time in sun, breaks, etc.), and placing barriers between waste pickers and the hazards (e.g., covered stations, flat ground, etc.) or more complex engineering, administrative or work controls. Because of the breadth of health problems faced by workers, more research is needed to correctly assess health outcomes (e.g. use of health practitioners) in waste pickers across time to ensure accurate data and a focused answer to the far-reaching problem.

Where Children Play: Young Child Exposure to Environmental Hazards during Play in Public Areas in a Transitioning Internally Displaced Persons Community in Haiti

Globally, gastrointestinal (GI) infections by enteric pathogens are the second-leading cause of morbidity and mortality in children under five years of age (≤5 years). While GI pathogen exposure in households has been rigorously examined, there is little data about young children's exposure in public domains. Moreover, public areas in low-income settings are often used for other waste disposal practices in addition to human feces, such as trash dumping in areas near households. If young children play in public domains, they might be exposed to interrelated and highly concentrated microbial, chemical, and physical hazards. This study performed structured observations at 36 public areas in an internally displaced persons community that has transitioned into a formal settlement in Haiti. We documented how often young children played in public areas and quantified behaviors that might lead to illness and injury. Children ≤5 years played at all public sites, which included infants who played at 47% of sites. Children touched and mouthed plastic, metal and glass trash, food and other objects from the ground, ate soil (geophagia) and drank surface water. They also touched latrines, animals, animal feces and open drainage canals. Hand-to-mouth contact was one of the most common behaviors observed and the rate of contact significantly differed among developmental stages (infants: 18/h, toddlers: 11/h and young children: 9/h), providing evidence that children could ingest trace amounts of animal/human feces on hands that may contain GI pathogens. These findings demonstrate that water, sanitation and hygiene interventions could be more effective if they consider exposure risks to feces in public domains. Furthermore, this research highlights the need for waste-related interventions to address the broader set of civil conditions that create unsafe, toxic and contaminated public environments where young children play.

Knowledge, practice and associated factors of infection prevention among healthcare workers in Debre Markos referral hospital, Northwest Ethiopia

BACKGROUND

Healthcare-associated infections are a major global public health agenda. Health care workers are front line of protecting themselves and clients from infection. This study examined the knowledge and practice of healthcare workers on infection prevention and its associated factors among health professionals working at Debre Markos Referral Hospital.

METHODS

A Hospital-based cross-sectional study was conducted with a structured pre-tested questionnaire among 150 participants. The healthcare workers were selected through systematic random sampling technique. Multivariate logistic regressions were computed to identify associated factors of knowledge and practice of infection prevention and variables with a p-value < 0.05 were considered statistically significant.

RESULTS

More than two thirds (84.7%) of healthcare workers were found to be knowledgeable but only 86 (57.3%) of respondents demonstrated a good practice on infection prevention. Older age, lengthy work experience and higher educational status were significantly associated with both knowledge and practice of infection prevention. In-service training, availability of infection prevention supplies and adherence to infection prevention guidelines was also associated with the practice of infection prevention.

CONCLUSIONS

The finding of this study revealed a good knowledge of infection prevention on the majority of participants with relatively minimal practice rate. Sociodemographic factors and health facility factors were associated with knowledge and practice of infection prevention. Hospitals and other concerned stakeholders should ensure constant availability of guidelines and the provision of training to health providers. Moreover, developing professionals' educational level, introducing infection prevention standard of practice and continuous mentorship was recommended.

Risk factors for Toxocara spp. seroprevalence and its association with atopy and asthma phenotypes in school-age children in a small town and semi-rural areas of Northeast Brazil

Toxocara canis, Toxocara cati, are roundworms that live in the intestines of dogs and cats, respectively, and are predominantly agents of human toxocariasis. Studies have suggested that Toxocara spp. seroprevalence increases levels of total and aeroallergen-specific IgE (sIgE), asthma prevalence and asthma morbidity. Nevertheless, other work reported a negative association between Toxocara spp. seropositivity with skin hypersensititity and a positive association with sIgE. The objective of the present study was to evaluate risk factors for acquiring Toxocara spp. infection and to investigate possible significant association between its seroprevalence with atopy and asthma. Students from elementary schools, residents in a small town and its surroundings of Northeast Brazil, underwent blood sampling to measure levels of anti-Toxocara spp. IgG, peripheral blood eosinophils, and specific IgE to aeroallergens. We used univariable and multivariable logistic regression analyses to assess possible risk factors for Toxocara spp. seropositivity and its association with atopy, wheeze/asthma with asthma phenotypes, in a sample of 791 elementary school children aged 6-13 years. Toxocara spp. seroprevalence reached 63.6%; 49.9% had sIgE; 7.2% and 3.3% had atopic wheeze/asthma and non-atopic wheeze/asthma respectively. Risk factors associated with Toxocara spp. seropositivity were: contact with dogs (adj. OR 2.33; 95% CI=1.70-3.19) and cats (adj. OR 3.09; 95% CI=2.10-4.55), and male sex (adj. OR 2.21; 95% CI=1.62-3.02). The presence of anti-Toxocara IgG was statistically associated with blood eosinophils >4% and >10% (adj. OR 1.84; 95% CI=1.33-2.55 and adj. OR 2.07; 95% CI=1.45-2.97, respectively), and atopy (adj. OR 2.00; 95% CI=1.49-2.68), but it was not associated with wheeze/asthma. Concluding, the results obtained in this study showing the association of Toxocara spp. seroprevalence with sIgE may suggest a possible immunological cross-reactivity between IgE epitopes from Toxocara spp. and aeroallergens.

Kinetic and avidity of IgY anti-Toxocara antibodies in experimentally infected chickens

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.

Detection of IgG against Toxocara in Sera of Employees of Meat Industry

Contact with raw meat could represent a risk for Toxocara infection. We assessed the association of Toxocara infection with an occupation of meat worker though a case-control seroprevalence study of 124 meat workers and 248 subjects without this occupation. Sera of participants was analyzed for the presence of anti-Toxocara IgG antibodies. One (0.8%) of the 124 meat workers, and 5 (2.0%) of the 248 controls were positive for anti-Toxocara IgG antibodies (OR=0.39; 95% CI: 0.04-3.41; P=0.66). The seropositive meat worker was a male aged 28 years old, without vision impairment. None of the work characteristics i.e. frequency of contact with raw meat, use of safety practices, history of splashes at face with blood or raw meat, and injuries with sharp material at work was associated with Toxocara exposure. Seroprevalence of Toxocara infection was significantly higher (P=0.04) in meat workers with consumption of boar meat (1/6: 16.7%) than in those without this consumption (0/117: 0%). We conclude that meat workers do not have a higher risk for Toxocara infection than subjects without this occupation do. The 2% seroprevalence of Toxocara infection found in control subjects might suggest a low seroprevalence of this infection among people with other occupations in Durango City. However, additional case-control studies with larger sample sizes to confirm our results are needed.

Zoonotic enteric parasites transmitted from dogs in Egypt with special concern to Toxocara canis infection

AIM

This work aimed to study the role played by dogs in transmitting zoonotic enteric parasites to humans in Egypt and to analyze the risk factors associated with the occurrence of such infection in dogs. Serodiagnosis of anti-Toxocara immunoglobulin G (IgG) antibodies among human beings as well as analyzing risk factors predispose to Toxocara canis infection in human beings are another objectives of this study.

MATERIALS AND METHODS

From June to December 2013, a total of 130 fecal samples from 4 dog populations (Military, nomadic and domiciled dogs from rural and high standard districts) and 150 stool samples of 6 occupational groups were examined for the presence of enteric parasitic infection. Moreover, 150 serum samples were collected from humans from whom stool samples were collected and examined for the presence of anti-T. canis antibodies.

RESULTS

Enteric parasites were detected in 30% of fecal samples from 4 dog populations in Egypt. High infectivity had been reported in nomadic dogs (63.33%) (Crude odds ratios [COR]=67.36, 95% confidence interval [CI]=8.09-560.8, p<0.000), followed by domiciled dogs from rural areas (40%) (COR=26, 95% CI=3.14-215.54, p=0.003), domiciled dogs from high standard areas (23.33%) (COR=11.87, 95% CI=1.37-102.69, p=0.025) and military dogs (2.5%). Twelve species of enteric parasites were identified, Ancylostomatidae (6.15%), T. canis and Cryptosporidium spp. (5.38%, each), Heterophyes spp. (3.85%), Toxocara leonina and Blastocystis spp. (3.07%), Taenidae eggs (2.31%), Hymenolepis diminuta (1.54%) and Entamoeba canis, Cyclospora cayetanensis, and Paragonimus spp. (0.77%, each). Univariate logestic regression revealed significant association of age (COR=4.73, 95% CI=2.13-10.53, p<0.000), gender (COR=2.63, 95% CI=1.22-5.68, p<0.014), housing system (COR=5.10, 95% CI=2.04-12.75), p<0.000) with enteric parasitic infection in dogs. However, breeds (COR=6.91, 95% CI=0.88-54.52, p=0.067) and type of feeding (COR ranged from 3.5 to 7.62, p>0.05) did not seem to have a significant association among the examined dogs. Enteric parasitic infection was reported in 31/150 human stools (20.67%). Students were the most affected groups (37.14%), followed by nomadic people (24%), house wives (20%), house guarders and military workers (12%, each), and employees (10%). The identified parasites were Cryptosporidium spp. (9.33%), Ascaris lumbercoides (3.33%), Heterophyes spp. and Ancylostoma spp. (2.66%, each) and Paragonimus spp. and Hymenolepis nana (1.33%, each). Toxocara IgG antibodies were detected in 36/150 (24%) serum samples investigated. Toxocara IgG antibodies were more prevalent in males (26.66%) than females (20%). Seroprevalence was highest (17/35, 48.57%) in 7-15 years old (COR=6.93, 95% CI=1.75-27.43, p=0.006). Seroprevalence values for T. canis antibodies were higher in those; raising dogs (29.85%), eating raw vegetables (25.21%) and not washing hands before meals (25.45%). T. canis antibodies were detected in 25% of those contacted with soil compared to 30% of those did not. Students were mostly affected (34.29%), followed by nomadic people (32%), house guarders (28%), housewives (20%), military workers (13%), and employees (10%).

CONCLUSION

Detection of enteric parasites in dogs and humans in Egypt substantiates the role posed by dogs in transmitting zoonotic parasites to humans and knock an alarm for common sources of infection for humans and dogs. Common sources may be infected fish or contaminated vegetables that are consumed by dogs or humans or even infected rodents that may contaminate their feed. This pilot study necessitate the need for similar studies and tracing such infection in fish, vegetables, rodent that may be responsible for infecting humans and dogs in order to understand the epidemiology of zoonotic parasitic infection transmitted from dogs to humans.

Vertical transmission of Toxocara canis in successive generations of mice

Visceral toxocariasis is a neglected zoonosis caused by Toxocara canis larvae in unusual hosts. In dogs, the definitive host, the infection occurs mainly through transplacental and transcolostral transmission. Studies on experimental models have shown that vertical transmission may result from acute infections. Considering that toxocariasis is characterized as a chronic infection, with possible reactivation of larvae present in the brain, this study evaluated the presence of larvae in the brain of female BALB/c mice and their offspring with chronic infection during three successive pregnancies. ELISA-TES was used to evaluate the antibody levels. T. canis larvae were detected in the brain tissue of the mice during the three successive generations evaluated. The offspring's IgG level gradually decreased, and mean absorbance (ABS) above the cutoff point (0.070) was observed only at 30 (0.229) and 50 (0.096) days of age, while IgM was not detected. The infections in the offspring confirmed that vertical transmission of T. canis larvae occurred during chronic toxocariasis in three successive generations of mice.

Seroepidemiology of Toxocara infection in patients with vision impairment and blindness in durango, Mexico

Background

Toxocara infection is a cause of vision impairment and blindness. We aimed to determine the seroprevalence and correlates of Toxocara infection in patients suffering from vision impairment and blindness in Durango City, Mexico.

Methods

Through a cross-sectional seroprevalence study, 204 patients with vision impairment and 19 blind patients were studied for the presence of anti-Toxocara IgG antibodies in Durango City, Mexico. Seroprevalence association with socio-demographic, housing, clinical, and behavioral characteristics of participants was also investigated.

Results

Five (2.5%) of the 204 patients with vision impairment, and none of the 19 patients with blindness were positive for anti-Toxocara IgG antibodies. In total, five of the 223 (2.2%) patients were positive for anti-Toxocara IgG antibodies. Seropositivity to Toxocara was not associated with age, sex, educational level, socio-economic status, presence of underlying diseases or behavioral characteristics of the patients. In contrast, multivariate analysis showed that Toxocara seropositivity was associated with living in a house with soil floor (odds ratio (OR) = 11.14; 95% confidence interval (CI): 1.57 - 78.74; P = 0.01).

Conclusions

This is the first report of Toxocara exposure in patients with vision impairment and blindness in Mexico, and of an association of Toxocara exposure with living in a house with soil floors. Results suggest a low Toxocara exposure in these patients in Durango, Mexico. The risk factor associated with Toxocara exposure identified in this study warrants for further investigation.

Low seroprevalence of Toxocara infection in schizophrenic inpatients in durango, Mexico: a case control study

Psychiatric patients have a higher seroprevalence of toxocariasis than general population. However, there is poor knowledge about any specific psychiatric diagnosis associated with toxocariasis. The aim of the study was to determine whether seropositivity to Toxocara was associated with schizophrenia. Through an age and gender-matched case-control seroprevalence study in Durango City, Mexico, 50 schizophrenic inpatients in a public psychiatric hospital and 100 control subjects of the general population were compared for the presence of anti-Toxocara IgG antibodies. One of the 50 (2%) schizophrenic inpatients, and 3 (3%) of the 100 controls were positive for anti-Toxocara IgG antibodies. No statistically significant difference in Toxocara seroprevalence among cases and controls was found (P=0.59). The Toxocara positive schizophrenic patient suffered from paranoid schizophrenia (F20.0) and had a number of putative risk factors for Toxocara exposure including contact with cats, dogs and other animals, worked in agriculture, and consumed undercooked meat, unwashed fruits and vegetables, and untreated water. Results suggest that seroprevalence of Toxocara infection was low and not associated with schizophrenia in psychiatric inpatients in Durango, Mexico. However, further studies to elucidate the association of toxocariasis with schizophrenia are needed.

Toxocariasis in North America: a systematic review

Toxocariasis is an important neglected tropical disease that can manifest as visceral or ocular larva migrans, or covert toxocariasis. All three forms pose a public health problem and cause significant morbidity in areas of high prevalence. To determine the burden of toxocariasis in North America, we conducted a systematic review of the literature following PRISMA guidelines. We found 18 articles with original prevalence, incidence, or case data for toxocariasis. Prevalence estimates ranged from 0.6% in a Canadian Inuit community to 30.8% in Mexican children with asthma. Commonly cited risk factors included: African-American race, poverty, male sex, and pet ownership or environmental contamination by animal feces. Increased prevalence of Toxocara spp. infection was linked in a group of case control studies conducted in Mexico to several high risk groups including waste pickers, asthmatic children, and inpatient psychiatry patients. Further research is needed to determine the true current burden of toxocariasis in North America; however the prevalence estimates gathered in this review suggest that the burden of disease is significant.

Toxocara infection in psychiatric inpatients: a case control seroprevalence study

BACKGROUND

There is poor knowledge about the epidemiology of toxocariasis in psychiatric patients.

AIMS

Determine the seroepidemiology of Toxocara infection in psychiatric patients.

METHODS

Through a case-control seroprevalence study, 128 psychiatric inpatients and 276 control subjects were compared for the presence of anti-Toxocara IgG antibodies in Durango, Mexico. Socio-demographic, clinical, and behavioral characteristics of inpatients associated with toxocariasis were also investigated.

RESULTS

Six of the 128 (4.7%) psychiatric inpatients, and 3 (1.1%) of the 276 controls were positive for anti-Toxocara IgG antibodies (P = 0.03). Stratification by age showed that Toxocara seroprevalence was significantly (P = 0.02) higher in patients aged ≤50 years old (6/90∶6.7%) than controls of the same age (2/163∶1.2%). While Toxocara seroprevalence was similar in patients and controls aged >50 years old. Stratification by gender showed that Toxocara seroprevalence was significantly (P = 0.03) higher in female patients (2/37∶5.4%) than in female controls (0/166∶0%). No statistically significant associations between Toxocara seropositivity and clinical characteristics were found. In contrast, Toxocara seropositivity was associated with consumption of goat meat and raw sea snail.

CONCLUSIONS

This is the first report of toxocariasis in psychiatric inpatients in Mexico. Further studies with larger sample sizes are needed to elucidate the association of toxocariasis with psychiatric diseases. The role of the consumption of goat meat and raw sea snail in the transmission of Toxocara deserve further investigation.