The prevalence of Toxocara canis ova in soil samples from parks and gardens in the London area

WormWatch: Park soil surveillance reveals extensive Toxocara contamination across the UK and Ireland

BACKGROUND

Toxocarosis is a globally distributed zoonotic disease, but sources of infection are not well documented over large geographical scales. To determine levels of environmental contamination, soil from 142 parks and recreational areas across the UK and Ireland was assessed for the presence of Toxocara.

METHODS

Toxocara ova (eggs) were isolated from soil samples by sieving and flotation and then enumerated. Individual eggs were isolated and imaged, and a subset was characterised by species-specific PCR and Sanger sequencing.

RESULTS

Characteristic Toxocara-type eggs were found in 86.6% of parks, with an average of 2.1 eggs per 50 g of topsoil. Representative eggs were confirmed as Toxocara canis by Sanger sequencing, with many eggs containing developed larvae, hence being viable and potentially infective. Positive samples were more common, and egg density was higher, in parks with greater perceived levels of dog fouling.

LIMITATIONS

Samples were collected at a single timepoint and with limited spatial mapping within parks. Further study is needed to discern spatiotemporal differences within parks and recreational areas.

CONCLUSION

Toxocara is widespread in soil in public parks, indicating a need for further efforts to reduce egg shedding from pet dogs. Standardised methods and large-scale surveys are required to evaluate risk factors for egg presence and the impact of interventions.

Spatial analysis of Toxocara spp. eggs in soil as a potential for serious human infection

Toxocara spp. cause one of the most widespread soil-transmitted helminthic infections worldwide. In both developed and developing countries, soil contamination with Toxocara eggs is considered as a major threat to public health. A total of 515 soil samples from 89 sampling sites were collected from different locations of public health such as Wastelands and Streets, public parks, and marginal areas. The soil samples were examined for Toxocara eggs using a centrifugal-floatation technique utilizing a saturated sodium nitrate solution. centralization of positive soil samples in the province was studied by Spatial Statistics Techniques such as Average Nearest Neighbors and Spatial Autocorrelation and Kernel Density Function Toxocara spp. eggs were found in 94 (18.25 %) out of 515 samples collected from the studied areas. According to the results obtained, marginal areas are often contaminated with eggs of Toxocara. Consequently, preventive measures including health education should be implemented to reduce the potential risk of this parasitic infection.

Ultrasonography for early diagnosis of Toxocara canis infection in puppies

Toxocara canis is one of the most common intestinal parasites in dogs and represents a highly infectious zoonotic parasite worldwide. Adult worms live in the bowel of dogs, and infections in puppies are commonly acquired transplacentally. The biology of the parasite and the commonly used diagnostic method, based on faecal examination, often prevent an early diagnosis of toxocariasis in puppies. Ultrasonographic diagnosis of intestinal ascariasis could be a feasible alternative method to diagnose T. canis infection in puppies during the prepatent period. The present study evaluated the diagnostic accuracy of ultrasonography for the diagnosis of intestinal toxocariasis in new-born puppies during the prepatent period. Fifty-four new-born puppies were prospectively recruited in the study. Each dog underwent intestinal ultrasonography and copro-microscopic examination every 5 days, starting from the 10th day post-birth. Intestinal ultrasonography visualized adult T. canis nematodes in the puppies' small intestine from the 10th day post-birth. On the 15th day after birth, ultrasonography showed 100% specificity and 85.4% sensitivity in diagnosing T. canis infection, despite negative results deriving from the copro-microscopic examination performed at the same time point. Our results showed that ultrasonography can be used as test for early diagnosis of T. canis infection in new-born puppies during the prepatent period. Early ultrasonographic diagnosis of T. canis infection in puppies could help control the disease in dogs and reduce the zoonotic risk for the human population.

Public Health Considerations Associated with the Location and Operation of Off-Leash Dog Parks

Off-leash dog parks may enhance human health, but may also lead to health risk through infection or canine aggression. Published evidence was reviewed to examine positive and negative public health impacts of off-leash dog parks, as well as strategies for enhancing benefits and mitigating risks. Evidence suggests that off-leash dog parks can benefit physical and social health, as well as community connectedness. While studies have documented shedding of zoonotic agents in dog parks, the risk of transmission to humans is relatively unknown. Evidence on the risk of dog bites in off-leash dog parks is also limited. Case-examples from North American off-leash dog parks highlight the importance of park location/design, public adherence to safe and hygienic practices, and effective regulatory strategies for mitigating potential risks and maximizing the benefits of off-leash dog parks.

Presence of helminth eggs in domestic wastewater and its removal at low temperature UASB reactors in Peruvian highlands

This work studied the anaerobic sludge filtration capacity for pathogens reduction in a 29 L and 1.65 m height lab-scale UASB reactor treating domestic wastewater at low temperatures in the city of Puno (Peru). The anaerobic sludge filtration capacity was performed applying upflow velocities of 0.12, 0.14, 0.16, 0.20, 0.27 and 0.41 m/h. Results show that the HE removal varied between 89 and 95% and the most common specie was Ascaris lumbricoides. Faecal coliform and Escherichia coli removal varied in the range of 0.9-2.1 and 0.8-1.6 log10 respectively. Likely related to the low operational temperatures, the total COD removal varied between 37 and 62%. The best performance in terms of removal of HE, total COD and turbidity was obtained at the lowest upflow velocity of 0.12 m/h. In order to meet WHO standards for water reuse a post-treatment unit will be required to polish the effluent.

Study on the contamination of Abadan public parks soil with Toxocara spp. eggs

BACKGROUND

Toxocariasis is one of the most important zoonotic diseases caused by Toxocara larva stage in humans. One of the major transmission routes of infection, especially in children is pica. The aim of this topic was study the contamination of Abadan public parks with Toxocara eggs.

MATERIALS AND METHODS

Two hundred and ninety one samples of soil were collected from 31 parks. The samples were examined for Toxocara spp. eggs by modified floatation method using saturated sucrose. The results were analyzed using SPSS version 19 and Chi-square test.

RESULTS

Eighty five (29.2%) out of 291 samples were infected with Toxocara spp. eggs, means19 (61.2%) of the 31 parks were contaminated. There was no significant difference between the urban and suburb parks contamination (p = 0.208) but there was significant relation between contamination with Toxocara spp. eggs and traces of cats and dogs presence in the parks (p = 0.001).

CONCLUSION

As the contamination of Abadan public parks soil with Toxocara spp. eggs is relatively high, the people and specially children might get the contamination during stay in the parks and measures should be taken to control the stray cats and dogs.

Detection of Toxocara eggs in contaminated soil from various public places of Chennai city and detailed correlation with literature

Toxocarosis is one of the most prevalent human helminthosis caused by larvae of Toxocara canis and Toxocara cati, the most widely distributed nematode parasites of dogs and cats respectively. Soil is considered as the principal source of transmission of Toxocara infection to human beings. With increasing population of dogs and cats, soil contamination with ova or eggs of Toxocara can be detected in public and private locations of city backyards, playgrounds, streets, sand pits and so on, regardless of the season of the year. In this context the present study was carried out to estimate the extent of soil contamination with Toxocara eggs in public parks, playgrounds and few kennels situated in different parts of Chennai city. A total of 105 soil samples from 40 public places and 5 kennels were screened for the presence of parasitic eggs. Toxocara eggs were recovered from 5 soil samples indicating an overall prevalence rate of 4.75 %. Out of 80 samples collected from public places, three samples, one each from Mogappair, My lady park (Periamet) and Madras Veterinary College showed the presence of Toxocara spp. eggs indicating an overall prevalence of 3.75 per cent. Out of the 25 samples from 5 kennels, two samples one each from Tambaram and Thorappakkam kennels were positive for Toxocara eggs with prevalence of 8 per cent. Low prevalence of Toxocara eggs in soil samples of these areas can be attributed to the less population of pups, the carriers of adult worms and the active source of soil contamination. The progress made in ABC (animal birth control) programme carried out by both governmental and non-governmental organizations has contributed to reduction of birth rate in dogs and thereby reduced the chances of soil contamination with Toxocara eggs to a certain extent in Chennai city.

Contamination of public parks and squares from Guarulhos (São Paulo State, Brazil ) by Toxocara spp. and Ancylostoma spp

The contaminated soil with mammal feces is an important factor of risk to infection with zoonotic diseases. Amongst these zoonoses are visceral larva migrans and cutaneous larva migrans caused by Toxocara spp. and Ancylostoma spp., respectively. The aim of this study was to assess the environmental contamination by Toxocara spp. eggs and hookworms (Ancylostoma spp.) in public parks and squares in the city of Guarulhos, a metropolitan area of São Paulo, São Paulo State, Brazil. Soil samples were collected, between September and December 2010, and examined using the centrifugal flotation technique with sodium dichromate and zinc sulphate as well as the modified Baermann method. Notably, 35 (74.5%) of the 47 districts surveyed in Guarulhos possessed samples contaminated with Toxocara spp. and/or eggs or larvae of Ancylostoma spp. The frequency of Toxocara spp. and Ancylostoma spp. in the samples from public areas was 68.1% and 46.8%, respectively. Overall, the eastern side of Guarulhos is the region with the highest occurrence of causative agents of larva migrans. In all collection sites, the presence of feces from dogs and cats accompanied by their owners and stray animals were observed. Notably, it is important to adopt measures to control dog and cat breeding, to treat infected animals, and provide health education to the population.

Seasonal contamination of public squares and lawns by parasites with zoonotic potential in southern Brazil

The presence of helminths and protozoans in public squares and lawns of the city of Maringá, southern Brazil, during winter and summer was assessed in order to evaluate their seasonal fluctuations in relation to edaphic and climatic factors. Samples were collected from January 2003 through June 2004 in 90% (13) of all public squares covered by sand, and in 30% (4) of all lawns used as leisure areas. The samples were analysed quantitatively by modified centrifugal-flotation and sedimentation in water techniques, and qualitatively by a method based on positive larval thermo-hydrotropism. Meteorological data were recorded, and physical, chemical and structural characteristics of the soil were analysed. One hundred and thirty samples of sand from squares, 65 in summer and 65 in winter, and 40 samples of grass from lawns, 20 in each season, were collected. All samples from lawns, 62 (95.38%) from squares in winter and 45 (69.23%) in summer, contained protozoans and/or helminths. Eggs of Toxocara spp. were the most frequently observed parasites in both winter and summer in squares (P < 0.0001) and in lawns (P = 0.6142), being equally distributed among the different locations (P = 0.2038). Species diversity was lower in winter; fewer parasites were found in summer. This region, with a tropical climate and a mild winter dry season, has favourable edaphic and climatic conditions for soil contaminants to persist year-round. In addition, the high frequency of animals such as dogs and cats and the poor sanitary measures in force made it possible for zoonoses to be transmitted in the public spaces.

Contamination of soil with Toxocara eggs in urban (Prague) and rural areas in the Czech Republic

Contamination of soil with feline and canine ascarid eggs in public parks, backyards and sand pits in Prague, Czech Republic was investigated in this work. Soil samples from shelters and rural areas were also collected. The comparison of soil from different areas (urban, rural, backyards and shelters) exhibited significant difference (chi(2)=32.16, d.f.=3 and p<0.0001). The highest rate of contamination (45%) was found in backyards inhabited by feral cats. The eggs of Toxocara spp. were found in 20.4% of parks, 10% of shelters and 5% of rural samples. Mean egg density per sample from Prague parks was 6.2 eggs/100g of soil. In 126 composite samples from children's and pits, the prevalence of Toxocara eggs was 11.90%. The number of eggs in positive samples varied from 2 to 22 (per 100g). A high proportion (46.9%) of eggs was fully embryonated. There was no difference between the sand pits with or without formal exclusion of dogs (chi(2)=0.6, d.f.=1 and p<0.0001).

Soil contamination with ascarid eggs in playgrounds in Kirikkale, Turkey

Contamination of soil with feline and canine ascarid eggs in eight playgrounds in Kirikkale, Turkey was investigated monthly from February 2003 to January 2004. Dog faeces were also collected and all samples were examined using the zinc sulphate centrifugal flotation method. Eggs of Toxocara were observed in 5 of 8 (62.5%) of playgrounds examined and in 15.6% of 480 soil samples. The number of eggs varied from 1 to 11. Eggs were observed in soil samples collected in February, March to June, August and November, with embryonated eggs appearing in June and August. Eggs of Toxascaris leonina and Taenia spp. and oocysts of Isospora spp. were also found in 1.5%, 1.0% and 0.2% of soil samples, respectively. Of 26 samples of dog faeces collected, 7.7% were contaminated with Toxocara spp. and 11.5% with Taenia spp. The presence of Toxocara eggs in the city playgrounds and dog populations suggests a potential human health hazard due to toxocariasis.

Visceral larva migrans associated with earthworm ingestion: clinical evolution in an adolescent patient

A 16-year-old girl developed a cough, hypereosinophilia (absolute eosinophil count: 32000/mm3), hypergammaglobulinemia, and multiple noncavitary pulmonary nodules 1 month after having ingested an earthworm on a dare. Spirometry revealed moderate restriction and reduced gas diffusion. Parabronchial biopsy demonstrated eosinophilic organizing pneumonitis with multiple eosinophilic microabscesses, and Toxocara titers were elevated (>1:4096). Ophthalmologic examination ruled out ocular larva migrans. The patient received a 10-day course of albendazole (400 mg orally twice daily) and demonstrated significant clinical improvement with resolution of cough and pulmonary function abnormalities. Her white blood cell count and hypergammaglobulinemia normalized within 20 days, yet eosinophils (absolute eosinophil count: 1780/mm3) and Toxocara serologies (>1:4096) remained elevated 3 months after completing antihelminthic therapy. In this instance, the ingested earthworm served as the paratenic carrier of Toxocara larvae from the soil to the patient. This case highlights the clinical evolution of pulmonary visceral larva migrans infection caused by Toxocara spp. associated with a discrete ingestion in an adolescent patient. In addition, it provides a rare opportunity to define the incubation period of visceral larva migrans and emphasizes the importance of education regarding sources of Toxocara infection.

The frequency rate of Toxocara species contamination in soil samples from public yards in a urban area "Payathai", Bangkok, Thailand

Toxocara species are most common roundworms of Canidae and Felidae. Human toxocariasis develops by ingesting of embryonated eggs in contaminated soil. There is no previous report of Toxocara contamination in the soil samples from the public areas in Bangkok. For this reason our study have been carried out to examine the frequency of Toxocara eggs in public yards in Bangkok, Thailand. A total of 175 sand and clay samples were collected and examined for parasite eggs. According to this study, Toxocara eggs were detected from 10 (5.71%) of 175 soil samples. The high rate of contamination in this study implies the importance of the control of this possible zoonotic disease: control of abandon of dogs and cats, is still necessary.

De la perrera municipal al centro de acogida de animales de compañía de Barcelona

This article aims to present changes in public health policy and services related to pet dogs and cats in the city of Barcelona from 1983 to 2001. Initially the center's activity was limited to the custody and euthanasia of stray animals, serving not only the city but also the rest of the province. With the formulation of a city Plan for Pet Animals, the activities were redirected, concentrating on services within the city limits and stimulating adoption. Participation of both professional and humane organizations was sought, premises were renovated, responsible ownership of animals was promoted, controlled urban colonies of cats were established, and adoptions become the cornerstone of policy, centering the activity of the shelter toward its clients. Changes in the shelter's activity since 1998 reflects a clear decrease in the number of animals retained, as well as in the proportion subjected to euthanasia. This decrease may reflect an improvement in the problem of stray animals. These developments have also resulted in a positive change in the relationship with the media and animal welfare organizations.

Environmental and serological evidence for the presence of toxocariasis in the urban area of Ancona, Italy

To evaluate the Toxocara spp. eggs environmental contamination of the soil of the urban or suburban area Ancona (Italy), 22 public playgrounds were selected and several cores of soil were taken from any selected areas. To study the Toxocara seroprevalence in the inhabitants of Ancona, blood samples were collected from selected groups of individuals. One hundred and sixty-three blood samples were tested using an enzyme linked immunosorbent assay (ELISA) technique (Lofarma Lab, Milan, Italy) for the detection of IgG-specific antibodies to T. canis excretory-secretory antigens. Toxocara spp. eggs were found in the soil samples from 14 (63.6%) playgrounds. Toxocara seroprevalence was detected in blood specimens from six (8.1%) out of 74 symptomatic individuals and from one (1.1%) out of 89 asymptomatic controls. Among symptomatic individuals, the association between Toxocara seroprevalence and eosinophilia resulted statistically significant (p = 0.029). The high environmental contamination frequency found make necessary to prompt preventive public health measures, such as control of stray animals, treatment of infected pets and hygiene education of the population.

Improved methods for recovering eggs of Toxocara canis from soil

The ingestion of soil in parks and public places containing eggs of Toxocara may constitute a significant health risk, particularly to children. To determine the most efficient method for extracting eggs from experimentally contaminated soil, two consecutive studies were undertaken. Four techniques, including washing, sieving, vacuum, and the one recommended by the World Health Organization, were evaluated. Recovery rates of over 85% were recorded with both washing and sieving methods. Using the washing technique, all combinations of the four pre-treatment solutions, distilled water, acetoacetic solution pH 5, 0.1 n sodium hydroxide and 1% Tween 20, and seven flotation fluids with different specific gravities (S.G.) ranging from 1.20 to 1.35 were assayed. The association of distilled water and saccharose solution with an S.G. of 1.27 showed the best results, with a recovery rate of 99.91%.

Comparison of methods of sampling for Toxocara species and fecal coliforms in an outdoor day care environment

OBJECTIVE

To compare three sampling methods and to pretest methods for the determination of fecal coliform (FC) counts and Toxocara species from sand in the day care outdoor environment.

DESIGN

The sand samples were obtained from the play area and the sandbox of a day care centre and examined for the presence of FC and Toxocara species, the common roundworm of dogs and cats. The sampling methods included random selection and two types of judgement methods. The latter included one method where domestic animals were judged to be likely to defecate and the other where children would be likely to be playing. In addition, to obtain a global estimate of contamination, the entire areas of both the sandbox and the play area were sampled on the last day.

SETTING

Outdoor day care environment.

MAIN RESULTS

The most representative levels of bacterial contamination and Toxocara species originated from the combined sample of the entire surface areas rather than from any separate random or judgement method of sampling. FCs were found in all sampled areas of the sandbox (median 910 FCs/g of sand) and of the play area (median 350 FCs/g of sand). Toxocara species were recovered from a number of areas in both the sandbox and the play area.

CONCLUSIONS

Research on environmental microbial contamination of outdoor day care settings would benefit from the application of standardized and validated sampling and laboratory methods.

Seroprevalence of Toxocara infection in middle-class and disadvantaged children in northern Spain (Gipuzkoa, Basque Country)

The prevalence of human toxocarosis in disadvantaged socioeconomic population in Europe is unknown. In Gipuzkoa the seroprevalence in middle-class children 2- to 5-years-old, and 6- to 16-year-olds, was zero (n = 135) and 4.4% (n = 320), respectively. In contrast, among socially and economically disadvantaged children the figures were 37% (n = 27) and 65.7% (n = 64). This high prevalence obliges us to consider toxocarosis as a public health problem.

Prevalence of Toxocara canis ova in public playgrounds in the Dublin area of Ireland

A total of nine playground sites in Dublin city and county were surveyed from which 228 samples were removed. Of these samples, 15% were positive for Toxocara canis ova and a mean egg density of 1.4 ova/100 g was calculated. Two types of playground sites were identified and that the level of toxocaral contamination was found to be greater in 'neighbourhood playgrounds' than in 'adventure playgrounds'. There was no significant difference in the number of positive samples taken from sites both inside and outside these playgrounds. No evidence of Toxocara cati ova was found. Only one sample was positive for Toxascaris leonina ova. Over 50% of the T. canis ova identified were infective. The findings in this study suggest that the sample's moisture content contributes to the long term survival of infective Toxocara ova in the environment. A recovery rate of 69.8% was achieved with a modified version of the flotation method.