Toxocara (Nematoda: Ascaridida) and other soil-transmitted helminth eggs contaminating soils in selected urban and rural areas in the Philippines

Climate influences the gut eukaryome of wild rodents in the Great Rift Valley of Jordan

BACKGROUND

The mammalian gut microbiome includes a community of eukaryotes with significant taxonomic and functional diversity termed the eukaryome. The molecular analysis of eukaryotic diversity in microbiomes of wild mammals is still in its early stages due to the recent emergence of interest in this field. This study aimed to fill this knowledge gap by collecting data on eukaryotic species found in the intestines of wild rodents. Because little is known about the influence of climate on the gut eukaryome, we compared the composition of the gut eukaryotes in two rodent species, Mus musculus domesticus and Acomys cahirinus, which inhabit a transect crossing a temperate and tropical zone on the Jordanian side of the Great Rift Valley (GRV).

METHODS

We used high-throughput amplicon sequencing targeting the 18S rRNA gene in fecal samples from rodents to identify eukaryotic organisms, their relative abundance, and their potential for pathogenicity.

RESULTS

Nematodes and protozoa were the most prevalent species in the eukaryome communities, whereas fungi made up 6.5% of the total. Sixty percent of the eukaryotic ASVs belonged to taxa that included known pathogens. Eighty percent of the rodents were infected with pinworms, specifically Syphacia obvelata. Eukaryotic species diversity differed significantly between bioclimatic zones (p = 0.001). Nippostrongylus brasiliensis and Aspiculuris tetraptera were found to be present exclusively in the Sudanian zone rodents. This area has not reported any cases of Trichuris infections. Yet, Capillaria infestations were unique to the Mediterranean region, while Trichuris vulpis infestations were also prevalent in the Mediterranean and Irano-Turanian regions.

CONCLUSIONS

This study highlights the importance of considering host species diversity and environmental factors when studying eukaryome composition in wild mammals. These data will be valuable as a reference to eukaryome study.

Molecular Determination of Toxocara spp. Eggs Isolated from Public Parks and Playgrounds in Zahedan, Southeast Iran

Background

Human toxocariasis (HT) is a zoonotic disease with a global expansion. Contaminated soil with Toxocara spp. eggs is the main source of human infection, which may lead to severe complications depending on the organs invaded by migrating larvae.

Aim

This study is aimed at eliciting the prevalence of Toxocara spp. eggs in public parks in Zahedan, southeast Iran, and providing new insight into the soil contamination rate in this area using microscopic and molecular methods.

Methods

Based on five municipal districts, 240 soil samples were collected from public parks and playgrounds in Zahedan. The modified Sheather's flotation technique was employed to isolate Toxocara spp. eggs from the soil, followed by microscopic assessment and molecular evaluation of internal transcribed spacer 1 and 2 ribosomal deoxyribonucleic acid (ITS1 and 2 rDNA) using nested polymerase chain reaction (nested PCR) to identify the presence of Toxocara spp. eggs. The Sanger sequence was used to differentiate the Toxocara species. Subsequently, all the sequenced data were blasted and compared with other sequences available in the GenBank.

Results

Out of 240 soil samples collected, 7 (2.9%) samples were identified to contain Toxocara spp. eggs using Sheather's flotation and microscopic techniques. Meanwhile, 19 (7.9%) samples were positive using nested PCR. According to the Sanger sequencing analysis findings, all positive samples were contaminated with Toxocara cati.

Conclusion

As evidenced by the obtained results, only T. cati species were detected in public parks and playgrounds in Zahedan; therefore, control and prevention programs against this species should be considered in human and animal communities.

Understanding the research and practical needs required to control toxocariasis in Iran

Human toxocariasis (HT) is a widespread zoonotic infection globally, notably prevalent in tropical areas. Enhancing our understanding of toxocariasis can lead to increased attention towards the socioeconomic impact and control of this neglected zoonosis. We conducted a comprehensive review of all available articles and official documents on toxocariasis in Iran to identify research gaps and critical needs for its control. This review highlights that despite numerous studies exploring various aspects of toxocariasis in definitive and paratenic hosts, as well as humans and environmental contamination, significant data deficiencies and gaps persist across different regions in the country. These gaps involve investigating the worm burden and reinfection rates in definitive hosts, developing more sensitive methods to detect and differentiate of Toxocara species, and understanding the behavior of definitive host animals. Additionally, identifying potential paratenic hosts for HT and exploring the organ-specific affinity and survival duration of Toxocara larvae within these hosts are essential areas for exploration. It's also imperative to comprehend the sylvatic and domestic cycles of the parasite in paratenic hosts. Furthermore, assessing egg density in the environment, exploring potential new sources such as water, and identifying regions with optimal climatic conditions for the survival and development of Toxocara eggs are crucial for the formulation of effective prevention and control strategies. Identifying at-risk groups, developing early diagnosis techniques, employing imaging methods, and identifying long-term complications in humans are also crucial. Community health organizations should prioritize health education for the public and professionals. Furthermore, accurately estimating definitive host populations, monitoring and preventing their movements in public places, implementing regular deworming practices for pets and stray hosts, and recognizing the infection's significance as a health priority are critical. This comprehensive understanding advocates for a holistic "one health" approach to control of HT.

Temporal and spatial patterns of Trichuris trichiura eggs: a potential threat to human health in Pakistan

This study investigates the presence of Trichuris trichiura eggs in soil samples collected from urban areas in Lahore, Pakistan. A total of 3600 soil samples were collected over two years from Lahore's urban regions. The detection of helminth eggs in these samples was performed using sodium hypochlorite (NaOCl) as a diagnostic technique. The study reveals an overall prevalence rate of T. trichiura at 0.97 % (35 out of 3600) in the contaminated soil samples from Lahore's slum areas. When analyzing the data by geographical areas, the study found the highest prevalence of T. trichiura in Allama Iqbal Town (1.83 %, 11 out of 600), followed by Samanabad (1.16 %, 7 out of 600), Wapda Town (1.00 %, 6 out of 600), Gulberg (1.00 %, 6 out of 600), and Cantt (0.50 %, 3 out of 600). Conversely, Valencia Town had the lowest prevalence rate at 0.33 % (2 out of 600). However, these variations in prevalence rates were not statistically significant (p = 0.117). Prevalence rates of T. trichiura's eggs varied significantly across different sampling seasons (p>0.001). In autumn, a total of 900 soil samples were collected, with 19 samples (2.11 %) testing positive for T. trichiura. This rate was notably higher compared to the prevalence rates observed in winter, spring, and summer, which were 0.66 %, 0.22 %, and 0.88 %, respectively. Regarding the sampling months, the study observed a significantly higher prevalence during September (3.33 %, 10 out of 300), followed by October (2.33 %, 7 out of 300), and August (1.33 %, 4 out of 300). Prevalence rates gradually decreased in other months, ranging from 1 % to 0.33 % (3 to 1 out of 300), with no parasite detection in March (0 %, 0 out of 300) (p < 0.001). This research underscores soil contamination due to fecal waste and highlights public unawareness of parasite biology, driven by open defecation practices.

Prevalence of Toxocara canis infection in dogs and Toxocara egg environmental contamination in Baybay City, Leyte, Philippines

Toxocara canis is a parasitic gastrointestinal nematode of dogs causing toxocariasis in humans, a neglected tropical disease. This study examined the burden of T. canis infection in dogs and egg contamination in school playgrounds and public parks in Baybay City, Leyte, Philippines. Fecalysis and egg detection in soils were performed to determine the parasite prevalence in dogs and the environment. In addition, pet owner's survey and GIS mapping were employed to identify the risk factors of infection and map the parasite distribution. Fecalysis revealed a T. canis prevalence of 64.44% (95% CI: 48.78-78.13) at the barangay level and 17.96% (95% CI: 14.12-21.80) at the animal level. Rural areas showed a much higher T. canis prevalence than urban. Factors associated with high T. canis infection included dog's age, specifically puppy (2-8 mo) relative to young (> 8-24 mo) [Adjusted Odds Ratio (AOR): 2.282; 95% CI: 1.137-4.579; p = 0.020] and adult (> 24 mo) (AOR: 3.542; 95% CI: 1.714-7.319; p = 0.001), access to dirty water (AOR: 2.749; 95% CI: 1.575-4.798; p < 0.001), and non-deworming (AOR: 2.961; 95%: CI 1.009-8.684; p = 0.048). Furthermore, we observed high Toxocara egg contamination in school playgrounds and public parks, with a prevalence of 51.11% (95% CI: 35.77-66.3) at the barangay level and 15.45% (95% CI: 10.67-20.23) in soil samples. This epidemiological study is the first in the central Philippines to report a high burden of T. canis infection in dogs and the environment, thus providing crucial data that will help understand the epidemiology of toxocariasis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-022-01525-y.

Seroprevalence of toxocariasis among allergic patients in Kuwait and its association with eosinophilia

Toxocariasis is a worldwide helminthic infection which is transmitted from infected dogs and cats and has been associated with peripheral blood eosinophilia. The Centers for Disease Control and Prevention (CDC) placed toxocariasis among the top 6 parasitic diseases in the USA which are prioritized for public health action. To our knowledge, there are no reports on human toxocariasis in Kuwait or in the other Gulf Cooperation Council (GCC) countries. This study aims at investigating the seroprevalence of toxocariasis among allergic patients in Kuwait and its association with eosinophilia, age, gender, nationality, and history of direct contact with dogs or cats. From September to December 2021, the laboratory records of allergic patients referred to Al-Rashed Allergy Hospital, Kuwait were reviewed and a total of 400 serum samples were selected: 200 samples from patients with normal eosinophil count (< 500 cells/μl) and 200 samples from patients with eosinophilia (> 500 cells/μl). The sera were screened for anti-Toxocara canis IgG antibodies via antibody enzyme-linked immunosorbent assay (Ab-ELISA). The seropositive patients were asked about their history of direct contact with dogs or cats. Statistical analyses were performed using Microsoft Excel® Analysis ToolPak software. Toxocariasis seropositivity was detected in 10 out of 400 (2.5%) allergic patients. Five patients had eosinophilia while 5 had normal eosinophil count. There was no difference in mean age or gender between Toxocara-seropositive and seronegative patients (p > 0.05). The seroprevalence rate was lower-than-expected among Kuwaiti patients (2/307, 0.7%) in comparison with non-Kuwaiti patients (8/57, 14.0%) (χ2 = 33.603, df = 1, p < 0.001) who originated from endemic South/Southeast Asian countries. Seven out of 8 (87.5%) seropositive patients had a history of direct contact with cats, dogs, or both. The seroprevalence rate of toxocariasis among allergic patients in Kuwait was 2.5%. Raising awareness and early deworming treatment/prophylaxis for juvenile dogs and cats remain crucial for toxocariasis prevention.

Environmental contamination with parasites in selected rural farms in the Philippines: impacts of farming practices on leafy greens food safety

Fresh vegetables are an important part of a healthy diet, however, they can also be agents of transmission of intestinal parasites. This study aimed to evaluate the presence of parasite contamination in vegetable farms as a source of transmission in selected rural communities in Laguna, Philippines. A total of 168 vegetable, 55 soil and 15 water samples collected from four selected farms and a reference farm were processed through various standard parasitological techniques. Of these, 17.3% of vegetables, 47.3% soil and 73.3% water samples were found contaminated with parasites’ eggs or cysts. Interestingly, leafy vegetables, such as lettuce, were found to be more contaminated. Results showed that strongylids/hookworms (egg/larva) showed the highest prevalence in farm soil (38.2%) and vegetable (13.1%); other helminth parasite eggs were also recovered such as Toxocara sp., Ascaris sp., Trichiuris, Trichostrongylus sp. and protozoan cysts of Balantidium coli. Cryptosporidium sp. oocysts of and Giardia sp. cysts were observed in all water samples in the farms. Furthermore, results revealed that some farming practices such as the use of improperly treated animals manure as fertilizers, unhygienic practice of farmers and sanitation issues were factors that contribute to parasite contamination in the farms. These findings have implications on food safety in poor-resource communities posing public health risks. Recommendations were discussed in the study for the control and prevention of parasite contamination at the farm level.

Knowledge of pet-related zoonotic diseases and pet care in Hong Kong, a heavily crowded urban setting

BACKGROUND

With the rapid expansion of pet animal populations worldwide, pet-related zoonotic diseases are becoming an important issue in public health. Hong Kong (HK), located in southern China, is one of the most crowded urban centres in the world. The population of pets, especially exotic pets, in HK has grown significantly in recent decades, potentially elevating the risk of pet-related zoonotic diseases. However, no studies have been conducted to explore the knowledge of HK public towards pet-related zoonotic diseases and animal husbandry practices.

OBJECTIVES

To evaluate the level of awareness among the HK public of pet-related zoonotic diseases and their understanding of proper animal husbandry practices.

METHODS

The study was carried out in HK from June-August 2019 using both online and paper versions of a questionnaire. A total of 362 completed questionnaires (74.3% return rate) were collected and the responses analysed.

RESULTS

Sixty percent of the participants were current or past pet owners or planned on becoming pet owners in the coming 2 years, irrespective of their income or size of their living space. Among the participants, pet owners (including those who planned pet ownership) had a relatively higher level of awareness of pet-related zoonotic disease. However, the overall awareness of zoonotic diseases among both pet and non-pet owners was low with a knowledge score of <50%. A similar trend was observed for knowledge about proper animal husbandry practices.

CONCLUSIONS

This study showed that the HK public was generally not familiar with pet-related zoonotic diseases and proper pet care. These knowledge gaps could potentially increase the risk of disease transmission. Further studies focusing on specific pet species and on people of different social-economic backgrounds are needed to provide future direction of efforts to reduce the risk of pet-related zoonotic diseases and to enhance pet-related animal and human welfare.

Soil Contamination with Toxocara Eggs in Public Schools in Rural Areas of Southern Thailand

Soil is considered the primary source of Toxocara transmission to humans, especially children. The status of soil contamination with Toxocara eggs in southern Thailand is unknown. This study aimed at estimating the soil contamination with Toxocara eggs in public schools in Nakhon Si Thammarat province in southern Thailand. Soil samples were collected from 12 public schools between August and September 2017. At each site, ten soil samples were collected from the following five types of locations: (1) playgrounds, (2) football fields, (3) sidewalks, (4) schoolyards, and (5) areas around cafeterias. In total, 120 samples were examined for Toxocara eggs with a modified flotation method using a sucrose solution. Toxocara eggs were detected in 8 (66.7%) of the 12 studied public schools. Of the 120 soil samples, 22 (18.3%; 95% CI: 11.9, 26.4) were contaminated with Toxocara eggs. The highest levels of Toxocara egg contamination were observed in playgrounds (41.7%; 95% CI: 22.1, 63.4), followed by football fields (20.8%; 95% CI: 7.1, 42.2), sidewalks (12.5%; 95% CI: 2.7, 32.4), and schoolyards (12.5%; 95% CI: 2.7, 32.4). There were significant differences in the distribution of Toxocara eggs across location types (p < 0.05). The findings demonstrated that the soil samples from public schools were contaminated with Toxocara eggs. Playgrounds were the most heavily contaminated locations. Teaching children proper handwashing steps and discouraging geophagia should be implemented to reduce the distribution of Toxocara and limit future Toxocara infections.

Excretory/Secretory Metabolome of the Zoonotic Roundworm Parasite Toxocara canis

Toxocariasis is a zoonotic disease affecting humans that is predominantly caused by Toxocara canis and T. cati, primarily parasites of dogs and cats, respectively. Toxocara generally establishes long-term infections by co-opting its host's physiological processes, while at the same time exploiting the nutritional environment. Adult stage T. canis reside in the gut of the definitive canine host where they employ a suite of strategies to combat intestinal immune responses by actively producing and releasing excretory-secretory products (ESPs). The protein component of T. canis ESPs has been widely studied, but characterisation of the non-protein ESP complement remains neglected. To characterize the secreted metabolome of Toxocara ESPs and to shed light on the parasite's metabolic processes, we profiled the ESPs of T. canis using both gas chromatography (GC) and liquid chromatography (LC) mass spectrometry approaches. We successfully identified 61 small molecules, including 41 polar metabolites, 14 medium-long chain fatty acids (MLCFAs) and six short chain fatty acids (SCFAs). We identified talose, stearic acid and isovalerate as the major compounds belonging to the polar, MLCFA and SCFA chemical classes, respectively. Most of the 61 identified metabolites appear to have been produced by T. canis via three distinct metabolic pathways - fatty acid, amino acid and carbohydrate metabolism. The majority of the identified ESPs have known biological properties, especially as immunomodulators. However, there is limited/no information on the biological roles or applications of 31 ESP biomolecules, suggesting that these may have novel activities that merit further investigation.

TroCCAP recommendations for the diagnosis, prevention and treatment of parasitic infections in dogs and cats in the tropics

The Tropical Council for Companion Animal Parasites Ltd. (TroCCAP) is a not-for-profit organisation whose mission is to independently inform, guide and make best-practice recommendations for the diagnosis, treatment and control of companion animal parasites in the tropics and sub-tropics, with the aim of protecting animal and human health. In line with this primary mission, TroCCAP recently developed guidelines for the diagnosis, treatment and control of feline and canine parasites in the tropics. The development of these guidelines required unique and complex considerations to be addressed, often inapplicable to developed nations. Much of the tropics encompass middle-to-low income countries in which poor standards of environmental hygiene and large populations of stray dogs and cats coexist. In these regions, a range of parasites pose a high risk to companion animals, which ultimately may place their owners at risk of acquiring parasitic zoonoses. These considerations led to the development of unique recommendations with regard, for example, to deworming and endoparasite testing intervals for the control of both global and 'region-specific' parasites in the tropics. Moreover, the 'off-' or 'extra'-label use of drugs for the treatment and control of parasitic infections is common practice in many tropical countries and many generic products lack manufacturers' information on efficacy, safety, and quality control. Recommendations and advice concerning the use of such drugs and protocols are also addressed in these guidelines. The formation of these guidelines is an important first step towards improving the education of veterinarians specifically regarding best-practice for the diagnosis, treatment and control of canine and feline parasites in the tropics.

Zoonotic transmission of intestinal helminths in southeast Asia: Implications for control and elimination

Intestinal helminths are extremely widespread and highly prevalent infections of humans, particularly in rural and poor urban areas of low and middle-income countries. These parasites have chronic and often insidious effects on human health and child development including abdominal problems, anaemia, stunting and wasting. Certain animals play a fundamental role in the transmission of many intestinal helminths to humans. However, the contribution of zoonotic transmission to the overall burden of human intestinal helminth infection and the relative importance of different animal reservoirs remains incomplete. Moreover, control programmes and transmission models for intestinal helminths often do not consider the role of zoonotic reservoirs of infection. Such reservoirs will become increasingly important as control is scaled up and there is a move towards interruption and even elimination of parasite transmission. With a focus on southeast Asia, and the Philippines in particular, this review summarises the major zoonotic intestinal helminths, risk factors for infection and highlights knowledge gaps related to their epidemiology and transmission. Various methodologies are discussed, including parasite genomics, mathematical modelling and socio-economic analysis, that could be employed to improve understanding of intestinal helminth spread, reservoir attribution and the burden associated with infection, as well as assess effectiveness of interventions. For sustainable control and ultimately elimination of intestinal helminths, there is a need to move beyond scheduled mass deworming and to consider animal and environmental reservoirs. A One Health approach to control of intestinal helminths is proposed, integrating interventions targeting humans, animals and the environment, including improved access to water, hygiene and sanitation. This will require coordination and collaboration across different sectors to achieve best health outcomes for all.

Soil-transmitted helminth (STH) eggs contaminating soils in selected organic and conventional farms in the Philippines

Soils from selected organic and conventional farms in the Philippines were examined for parasite contamination. A total of 600 soil samples from twenty organic and conventional farms were collected and processed through modified sucrose floatation technique. Results revealed that 248 out of 600 (41.33%) soil samples were contaminated with parasite eggs. Parasites recovered were Ascaris spp. (39.0%), Trichuris spp. (26.0%), hookworm/strongylid (22.0%), Toxocara spp. (4.0%), Taenia spp. (3.0%), and some unidentified eggs (6.0%). Contamination rate was found higher in organic (48.30%) than in conventional farms (37.67%) (p = 0.834; not significant); and significantly higher in Southern (64.40%) than in Northern Luzon region (31.40%) (p = 0.015). In addition, contamination rate between soil depths was not statistically significant (p = 0.24), with depth 1 (0-5 cm) at 43% and depth 2 (6-10 cm) at 39.67%. Furthermore, some farming practices were recorded through survey and results revealed that the use of manure as fertilizer (p = 0.017) and wash water (p = 0.014) showed significant positive relationship with parasite contamination in soil. These findings have implications on food safety and could be used to help the agriculture sector and other stakeholders in their efforts to improve food safety policies.

Knowledge, attitude and practice with respect to soil contamination by Soil-Transmitted Helminths in Ibadan, Southwestern Nigeria

Ancylostoma duodenale, Necator americanus, Ascaris lumbricoides and Trichuris trichiura, the four major Soil-transmitted helminths (STHs) and also Strongyloides stercoralis infect humans worldwide. Most studies on Soil-transmitted helminths (STHs) carried out in Ibadan were faecal examination based while relatively few soil examination based studies were carried out mostly around school premises using limited number of sampling locations. This study was therefore designed to assess the level of soil contamination with STH and associated risk factors in the eleven local government areas of Ibadan. A total of 1980 soil samples were purposively collected monthly, between January and December 2017, from toilet areas, refuse dump sites, house vicinities, playgrounds, roadsides/walk ways, and examined for the presence of parasite eggs or larvae using automated analysis of light microscopy images by computer. Well-structured questionnaires were administered to 620 consenting participants to obtain information on the Knowledge of STH infections, Attitudes and Practices towards the infections. Data were analyzed using SPSS version 21, Chi-square and ANOVA were used in the analysis at p < 0.05. Out of soil samples examined, 1087 (54.9%) had at least one species of parasite. The prevalence of hookworm was 74.5% followed by 50.2% and 37.2% for Strongyloides species larvae and adult respectively, and 25.1% for Ascaris species. The highest prevalence was observed in the refuse dump (74.2%) followed by toilet area (36.5%) while the lowest was at house vicinities (1.6%). Fifty-seven percent of the respondents use pit latrine while 20.6% still practice open defecation. A high transmission risk was observed as large percentage (66.8%) of the respondents showed inadequate knowledge of how to avoid STH infections. Moreover, 64.0% and 25.2% reported that they often walk barefooted and suck fingers respectively. The high prevalence of parasitic contamination of soil observed in the present study and the high proportion of respondent with inadequate knowledge of how to prevent transmission of STH pose a high risk of re-infections in the study area even after treatment. Therefore there is a need for proper education on parasite transmission in the area.

Molecular characterization of Toxocara spp. eggs isolated from public parks and playgrounds in Shiraz, Iran

Human toxocariasis, a worldwide parasitic disease, is caused by the larval stage of intestinal nematodes of dogs and cats, namely Toxocara canis and Toxocara cati. Human infection occurs by the accidental ingestion of embryonated eggs present in the soil, vegetables or on other contaminated surfaces, as well as via consumption of uncooked paratenic hosts, such as bird meat and giblets. The objective of this study was to evaluate the contamination of soil in public parks and playgrounds in Shiraz using microscopy and molecular methods. A total of 150 soil samples were collected from public parks and playgrounds in various areas of Shiraz, southern Iran. The samples were treated with saturated zinc sulphate solution, and Toxocara spp. eggs were detected by microscopic observation followed by nested polymerase chain reaction (PCR). To differentiate T. canis and T. cati eggs from each other, PCR restriction fragment length polymorphism (RFLP) of the internal transcribed spacer (ITS)-rDNA region by SalI endonuclease enzyme was used. PCR-sequencing was performed to confirm the results of the PCR-RFLP method. Based on the flotation results of the 150 soil samples, six (4%) were found to be positive for Toxocara spp. eggs, whereas nested-PCR showed 24 samples to be positive (16%). Based on the PCR-RFLP method and the sequence of the ITS-rDNA region, a total of 23 out of 24 isolates were confirmed as T. cati and one out of 24 as T. canis. The results showed a higher number of soil samples to be positive for Toxocara by the molecular method than microscopy, and higher T. cati infection in soil samples, which could have an important role in human infection with toxocariasis in this region.

Distribution and risk factors of Ascarididae and other geohelminths in the soil of Uberlandia, Minas Gerais, Brazil

Among the geohelminths, parasites from the Ascarididae family have a significant role in the human and animal health. This research aims to determine the prevalence of Ascarididae species in the soil in different areas located in a city of Minas Gerais State, Brazil (South America). The study was developed in squares, parks, sports clubs, orchards and municipal children's schools. Samples of sand/soil/grass were collected from January to August 2014. The optical microscope screening was performed through formal-ether and spontaneous sedimentation techniques. Out of the 183 collected samples, eight (4.4%) belonged to parks, 16 (8.7%) to sports clubs, 76 (41.5%) to squares, 23 (12.6%) to orchards, and 60 (32.8%) to schools. Out of the total, 28 (15.3%) contained Ascarididae eggs. Higher levels of positivity were demonstrated in the raining season (25.0%), in samples collected in the southern region of the town (25.1%), on ground soils (27.3%). Twenty-three (12.6%) were detected by the formal-ether sedimentation technique and 10 (5.5%) by spontaneous sedimentation technique. Therefore, it was concluded that the soils in the city of Uberlandia are contaminated with eggs and larvae of geohelminths, enabling dissemination of illnesses among animals and human beings.

Dot enzyme-linked immunosorbent assay (ELISA) for the detection of Toxocara infection using a rat model

Toxocariasis is a zoonotic disease usually caused by dog and cat roundworms, Toxocara canis and T. cati. Detection and diagnosis is difficult in paratenic and accidental hosts, including humans, as they cannot be detected through conventional methods such as fecal examination. Diagnosis therefore relies on immunological methods and molecular methods such as enzyme-linked immunosorbent assay (ELISA) and Western Blot, which are both time-consuming and requires sophisticated equipment. In the Philippines, only a few studies are available on Toxocara seroprevalence. Therefore, there is a need to adapt methods for serodiagnosis of Toxocara infection in humans for the Philippine setting. A dot enzyme linked immunosorbent assay (dot-ELISA) was standardized using T. canis excretory-secretory antigens. Test sera were collected from laboratory rats (Sprague-Dawley strain) experimentally infected with embryonated eggs of T. canis and Ascaris suum as well as rice field rats naturally infected with Taenia taeniaeformis and Nippostrongylus sp. Optimum conditions used were 20 µg/ml antigen concentration and 1:10 serum dilution. The sensitivity, specificity, positive, and negative predictive values were 90% (95% CI 55.5-99.7%), 100% (95% CI 69.2-100.0%), 100% (95% CI 66.4-100%), and 90.9% (95% CI 58.7-99.8%), respectively. Dot-ELISA has the potential to be developed as a cheaper, simpler, and more practical method for detection of anti-Toxocara antibodies on accidental hosts. This is a preliminary study conducted on experimental animals before optimization and standardization for human serum samples.

Toxocara canis: anthelmintic activity of quinone derivatives in murine toxocarosis

Human toxocarosis is a chronic tissue parasitosis most often caused by Toxocara canis. The seroprevalence can reach up to 50%, especially among children and adolescents. The anthelmintics used in the treatment have moderate efficacy. The aim of this study was to evaluate the in vitro and in vivo anthelmintic activity of quinones and their derivatives against T. canis larvae and the cytotoxicity of the larvicidal compounds. The compounds were evaluated at 1 mg mL(-1) concentration in microculture plates containing third stage larvae in an Roswell Park Memorial Institute (RPMI) 1640 environment, incubated at 37 °C in 5% CO2 tension for 48 h. Five naphthoxiranes were selected for the cytotoxicity analysis. The cell viability evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays using murine peritoneal macrophages isolated from C57BL/6 mice revealed that the naphthoxiranes (1 and 3) were less cytotoxic at a concentration of 0.05 mg mL(-1). The efficacy of naphthoxiranes (1 and 3) was examined in murine toxocarosis also. The anthelmintic activity was examined by evaluating the number of larvae in the brain, carcass, liver, lungs, heart, kidneys and eyes. Compound (3) demonstrated anthelmintic activity similar to that of albendazole by decreasing the number of larvae in the organs of mice and thus could form the basis of the development of a new anthelmintic drug.