Worldwide absence of canonical benzimidazole resistance-associated mutations within ß-tubulin genes from Ascaris.

BACKGROUND: The giant roundworm Ascaris is an intestinal nematode, causing ascariasis by infecting humans and pigs worldwide. Recent estimates suggest that Ascaris infects over half a billion people, with chronic infections leading to reduced growth and cognitive ability. Ascariasis affects innumerable pigs worldwide and is known to reduce production yields via decreased growth and condemnation of livers. The predominant anthelminthic drugs used to treat ascariasis are the benzimidazoles. Benzimidazoles interact with ß-tubulins and block their function, and several benzimidazole resistance-associated mutations have been described in the ß-tubulins of ruminant nematodes. Recent research on ascarids has shown that these canonical benzimidazole resistance-associated mutations are likely not present in the ß-tubulins of Ascaris, Ascaridia or Parascaris, even in phenotypically resistant populations. METHODS: To further determine the putative absence of key ß-tubulin polymorphisms, we screened two ß-tubulin isotypes of Ascaris, highly expressed in adult worms. Using adult and egg samples of Ascaris obtained from pigs and humans worldwide, we performed deep amplicon sequencing to look for canonical resistance-associated mutations in Ascaris ß-tubulins. Subsequently, we examined these data in closer detail to study the population dynamics of Ascaris and genetic diversity within the two isotypes and tested whether genotypes appeared to partition across human and pig hosts. RESULTS: In the 187 isolates, 69 genotypes were found, made up of eight haplotypes of ß-tubulin isotype A and 20 haplotypes of isotype B. Single nucleotide polymorphisms were seen at 14 and 37 positions for ß-tubulin isotype A and isotype B, respectively. No evidence of any canonical benzimidazole resistance-associated mutations was found in either human- or pig-derived Ascaris isolates. There was, however, a difference in the genetic diversity of each isotype and distribution of ß-tubulin genotypes between human- and pig-derived Ascaris. Statistical tests of population differentiation show significant differences (p < 0.001) between pig- and human-derived worms; however, more diversity was seen between worms from different populations than worms from different hosts. CONCLUSIONS: Our work suggests an absence of canonical ß-tubulin mutations within Ascaris, but alternative modes of anthelminthic resistance may emerge necessitating continued genetic scrutiny alongside monitoring of drug efficacy.

Prevalence and Molecular Characterization of Ascaridoid Parasites of Philippine Decapterus Species.

There are relatively few studies on parasite fauna of marine fishes in Philippine waters. This study aimed to determine the prevalence of marine ascaridoid infection in Decapterus species in Balayan Bay and Tayabas Bay. A total of 371 fishes belonging to three different species of Decapterus (D. tabl [n = 130], D. macrosoma [n = 121], and D. maruadsi [n = 120]) were collected. Ascaridoid parasite larvae were found in all fish host species, with an overall fish infection rate of 22%. The highest infection rate was observed in D. tabl (27.69%), followed by D. macrosoma (19%), and then D. maruadsi (17.50%). Moreover, a higher prevalence of infection was detected in Tayabas Bay (27.57%) than in Balayan Bay (15.59%). Molecular analyses based on the ITS2 and 18S rRNA gene supported the identification of the larvae into two species: Anisakis typica and Raphidascaris (Ichthyascaris) lophii. This is the first report of the genetic identification of these two helminth parasites in Decapterus fish species in the Philippines. Paucity in the database of Philippine marine fish parasites warrants more research efforts, especially concerning economically important fish species with implications to food safety and food security.

T oxocara canis prevalence in soil, dog stool, and human serum samples from a rural village in Los Baños, Laguna, Philippines.

Toxocariasis is a zoonotic disease caused by Toxocara spp. from dogs and cats. The Philippines is among the countries recorded to have abundant stray cats and dogs; however, few studies have been done to elucidate the transmission dynamics and the potential risks associated with toxocariasis. This study was conducted in a rural village in Los Baños, Laguna, Philippines to determine the prevalence of toxocariasis among selected public schoolchildren and identify some risk factors that can contribute to the transmission dynamics of toxocariasis in the study site. To elucidate this, serum samples from 50 public school children (ages 8-13) were tested using a Toxocara canis IgG ELISA kit, while 60 randomly selected households were chosen for collection of soil and dog samples. Sixty soil and dog fecal samples were collected and processed through modified sucrose flotation technique and formalin-ethyl acetate concentration technique, respectively. Knowledge, attitudes and practices (KAP) survey was conducted per household to determine potential risk factors. Results revealed that 60% of the public-school children examined were positive for anti-Toxocara canis antibodies, while 38.3% of the soil samples and 28% of the dog fecal samples were found positive for contamination with Toxocara ova. Deworming of pets was found to be significantly correlated to risk factors of infection (p < 0.05). This study highlights the potential risks of toxocariasis infection of residents in rural communities. Strict implementation of ordinances related to responsible pet ownership as well as promotion of sanitation and hygiene should be employed.

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.

Diet, parasites, and other pathogens of Sunda leopard cats (Prionailurus javanensis Desmarest 1816) in Aborlan, Palawan Island, Philippines.

This study is the first investigation of parasites and other pathogens present in Sunda leopard cats (Prionailurus javanensis) in Aborlan, Palawan, Philippines. With the nature of wild carnivore sampling, four (4) wild Sunda leopard cats were captured in Aborlan, Palawan, Philippines for a period of nine (9) months. Of these, three (3) were considered for blood and fecal examination due to the poor condition of one animal. Rapid diagnostic kits were used to detect the presence of selected pathogens in blood samples while fecal samples were examined for parasite fauna and diet contents. Nine (9) parasite species were identified namely: Toxoplasma gondii, Ancylostoma sp., Capillaria hepatica, Echinostoma sp., Hymenolepis nana, Isospora felis, Physaloptera sp., Trichostrongylus sp., and a fasciolid. Chlamydophila felis, a bacterial pathogen was also detected in the blood. No individuals were found to be positive for feline immunodeficiency virus, feline infectious peritonitis virus, and feline leukemia virus antibodies. Six (6) small mammal prey species were identified from the feces of Sunda leopard cats namely: Palawan spiny rat (Maxomys panglima), Asian house rat (Rattus tanezumi), Polynesian rat (Rattus exulans), house mouse (Mus musculus), Southern Palawan tree squirrel (Sundasciurus steerii), and Palawan treeshrew (Tupaia palawanensis). Sunda leopard cats in Aborlan, Palawan, may be highly infected by parasites primarily due to their diet of small mammals such as rodents. Transmission is also possible through environmental contact with contaminated water or soil or direct physical contact with infected domestic animals. This paper contributes to the knowledge on host-parasite systems in wildlife ecosystem in the Philippines which is extremely poorly understood.

Angiostrongylus cantonensis infection of non-native rats in Mount Makiling Forest Reserve, the Philippines.

A number of studies had been conducted on rat species diversity in the Philippines, however, there is a dearth of information on the extent of Angiostrongylus spp. infection in various ecological niches. Collection of non-native rat samples occurred in various sampling sites categorized as residential, agricultural and agro-forest in Philippine Mount Makiling Forest Reserve (MMFR) and its adjacent areas . Three species of non-native rats were captured including Rattus tanezumi, Rattus norvegicus and Rattus exulans. Of the total 90 non-native rats collected, 24.4% were found infected with Angiostrongylus cantonensis. Statistical analysis showed significant difference among rat species with highest prevalence observed in R. exulans (42.9%) followed by R. tanezumi (29.8%) and R. norvegicus (7.7%) (P = 0.047). Angiostrongylus cantonensis infection was significantly higher in adults (29.4%) than in juvenile rats (9.1%) (P = 0.050). However, results showed no significant difference in A. cantonensis infection between male (43.3%) and female (18.3%) rats and between wet (31.6%) and dry seasons (19.2%) (P > 0.05). Moreover, this study also revealed that rats from agricultural and agro-forest areas showed significantly higher prevalence than residential areas. With urbanization and the everchanging landscape of MMFR watersheds and buffer zones, zoonotic transmission can pose health threats to the local people.

Histopathological features and prevalence of Capillaria hepatica infection in Rattus spp. in Philippine Mount Makiling forest reserve and its adjacent areas.

Rats are recognized as reservoir hosts of several pathogens that pose a threat to human health. Although rats are reported to be hosts of a large number of pathogens, a survey of Capillaria hepatica carried by rats in various settings such as residential, agroforestry, and agricultural areas in the Philippines has not been conducted. A total of 90 rats composed of Rattus norvegicus, Rattus tanezumi, and Rattus exulans were collected through trapping in selected residential, agroforestry, and agricultural areas in Los Baños Laguna, Philippines. The overall prevalence of C. hepatica among rats was 21.11%. Among the rat species collected, R. norvegicus showed the highest prevalence (55.56%), followed by R. exulans (14.29%), then R. tanezumi (5.36%) (differences significant at p < 0.05). Moreover, residential areas had the highest prevalence of C. hepatica infection (50%), followed by agroforestry and agricultural areas at 6.7% each (significant at p < 0.05). However, the difference in C. hepatica infection between male (11.43%; 4/35) and female (27.27%; 15/55) rats was not significant (p > 0.05). Most of the infected rats were moderately infected (68.42%), while few were lightly and severely infected (15.78% each). Lastly, the presence of C. hepatica in liver is suggestive of presence of lymphocytes, amyloid, granuloma, and the occurrence of necrosis, hypertrophy, fibrosis, and cholestasis in the liver of the host. Capillariasis could be occurring in Philippine human populations, hence there is need for screening the population with appropriate means and to create awareness of this emerging disease.

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.

Larval distribution, migratory pattern and histological effects of Toxocara canis in Rattus norvegicus.

The common dog roundworm Toxocara canis can infect other animals and humans which may act as their paratenic and accidental hosts, respectively. Larvae do not further develop to adult worms in these hosts. Instead, they undergo migration to various body organs, causing the neglected parasitic disease known as toxocariasis. Although rats are considered as potential paratenic hosts of the parasite, there are only few studies which utilized Rattus norvegicus (Sprague-Dawley strain) for experimental infections involving toxocariasis. This study aimed to determine whether T. canis could establish in Sprague-Dawley rats artificially infected with 500 T. canis embryonated eggs and if the animals can be used as animal models for toxocariasis. Following squash method and tissue digestion, larvae were recovered from the lungs, liver and brain of the infected rats. Furthermore, gross examination of organs revealed macroscopic lesions and hemorrhages in the lungs and brain. Microscopically, accumulation of inflammatory cells, thickening of alveoli lining and destruction of bronchial walls and hepatic necrosis were observed. This study showed that T. canis has established in Sprague-Dawley rats and could serve as a model for Toxocara infection studies.

Occurrence of Angiostrongylus cantonensis in rodents from the rice granary of the Philippines and associated risk factors for zoonotic transmission.

Rattus tanezumi and Rattus norvegicus are the most common rodent species in the Philippines, with the former mainly inhabiting agricultural land and the latter in urban areas. Generating information on the Angiostrongylus cantonensis harbored by these rodents would be useful for public health. A total of 600 rodents were collected from traps placed each month from July to December 2012 in selected villages of Muñoz, Nueva Ecija; the rice granary of the Philippines. The prevalence of A. cantonensis in R. tanezumi and R. norvegicus was, 100%; all the rodents from the five villages were infected. The study shows that regardless of stages, body weight and length, rodents are vulnerable to infection by Angiostrongylus cantonensis present in the environment. However in terms of sex, results revelead that the male and female in R. tanezumi has no statistically significance while R. norvegicus revealed that male and female has statistically significance. This study also show that, rodents that were caught in the agricultural area has higher mean intensity compared to rodents that were trapped in the residential areas but found to be insignificant. Also through survey interviews the various risk factors with zoonotic implication of A. cantonensis in the area was also discussed.

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.

Study of six patients with complete F9 deletion characterized by cytogenetic microarray: role of the SOX3 gene in intellectual disability.

Essentials Some hemophilia B (HB) patients with complete F9 deletion present with intellectual disability (ID). We delineate six F9 complete deletions and investigate genotype/phenotype correlation. We identify SOX3 as a candidate gene for ID, acting through haploinsufficiency, in HB patients. All complete F9 deletions in ID patients should be explored with cytogenetic microarrays. SUMMARY: Background Large deletions encompassing both the complete F9 gene and contiguous genes have been detected in patients with severe hemophilia B (HB). Some of these patients present other clinical features, such as intellectual disability (ID). Objectives/Methods In this study, we characterized six unrelated large deletions encompassing F9, by cytogenetic microarray analysis (CMA), to investigate genotype/phenotype correlation. Results Five of the six patients included in this study presented with ID associated with HB. CMA showed that the six large deletions, ranging in size from approximately 933 kb to 9.19 Mb, were located within the Xq26.3 to Xq28 bands. In all cases, the complete deletion of F9 was associated with the loss of various neighboring genes (5-28 other genes). The smallest region of overlap for ID was a 1.26-Mb region encompassing seven OMIM genes (LOC389895, SOX3, LINC00632, CDR1, SPANXF1, LDOC1, SPANXC). SOX3, our candidate gene for ID, encodes an early transcription factor involved in pituitary development. All of the patients studied who had both HB and ID had deletion of the SOX3 gene. Conclusions All HB patients with an atypical phenotype, especially if complete deletion of F9 is suspected, should be referred to a geneticist for possible pangenomic assessment, because haploinsufficiency of genes flanking F9, such as SOX3 in particular, may result in a broader phenotype, including ID. Such assessment would be of particular value for the genetic counseling of female carriers with F9 deletions, as it would facilitate analysis of the risk of transmitting HB associated with ID.

Vectors and Spatial Patterns of Angiostrongylus cantonensis in Selected Rice-Farming Villages of Muñoz, Nueva Ecija, Philippines.

In the Philippines, rats and snails abound in agricultural areas as pests and source of food for some of the local people which poses risks of parasite transmission to humans such as Angiostrongylus cantonensis. This study was conducted to determine the extent of A. cantonensis infection among rats and snails collected from rice-farming villages of Muñoz, Nueva Ecija. A total of 209 rats, 781 freshwater snails, and 120 terrestrial snails were collected for the study. Heart and lungs of rats and snail tissues were examined and subjected to artificial digestion for parasite collection. Adult worms from rats were identified using SSU rDNA gene. Seven nematode sequences obtained matched A. cantonensis. Results revealed that 31% of the rats examined were positive with A. cantonensis. Rattus norvegicus and R. tanezumi showed prevalence of 46% and 29%, respectively. Furthermore, only Pomacea canaliculata (2%) and Melanoides maculata (1%) were found to be positive for A. cantonensis among the snails collected. Analysis of host distribution showed overlapping habitats of rats and snails as well as residential and agricultural areas indicating risks to public health. This study presents a possible route of human infection for A. cantonensis through handling and consumption of P. canaliculata and M. maculata or crops contaminated by these snails.

Acanthocephalan Parasites (Acanthogyrus sp.) of Nile Tilapia (Oreochromis niloticus) as Biosink of Lead (Pb) Contamination in a Philippine Freshwater Lake.

The potential use of acanthocephalans as bioindicators of Lead (Pb) pollution in Sampaloc Lake, Laguna, Philippines was investigated. Nile tilapias (Oreochromis niloticus) were collected and Pb concentrations were determined in fish tissues and in their acanthocephalan parasites, Acanthogyrus sp. Significantly higher levels of Pb were detected in the parasites relative to the fish host tissues (p = 0.001). Bioaccumulation capacity of the parasites against fish tissues were 102, 119, and 147 times higher than the fish intestine, liver, and muscles, respectively. Pb sensitivity of the parasites was quantified by exact logistic analysis showing higher odds of Pb detection ranging from 18 to 45 folds (p = 0.001-0.009). Interestingly, infected fish showed significantly lower Pb concentration in their tissues compared to uninfected fish (p = 0.001), suggesting parasites were able to sequester Pb and served as active biosinks. The Pb levels in the parasites were also hundred folds higher (988 times) relative to the ambient waters, indicating a potential role of fish parasites as metal biosinks in aquatic ecosystems.

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

The extent of contamination of soils with soil transmitted helminthes (STH) eggs, particularly Toxocara, was determined in selected urban and rural towns of Laguna, Philippines. Soil samples were collected from public schools, house yards, and empty lots. Results revealed that, of the 1480 soil samples collected, 460 (31%) were positive for STH eggs. Toxocara sp. was the most prevalent (77%), followed by Ascaris sp. (11%), hookworms/strongyles/free-living nematodes (7%), and Trichuris sp. (5%). Some soil physicochemical parameters were also determined and associated with Toxocara eggs prevalence and density in soil. Results revealed that Toxocara sp. eggs were most prevalent in less acidic, relatively high temperature and high moisture soil conditions. They were also prevalent in sandy, silty, and loamy soil textures but less prevalent in clayey. No significant differences were found between depth 1 (0-5 cm) and depth 2 (6-10 cm). This study revealed that Toxocara sp. eggs are ubiquitous and the extent of contamination in soils from the selected towns of Laguna is relatively high. Hence, the data generated in this study can be used in promoting public awareness, particularly for pet owners and local health officials, for effective prevention and control of this parasitosis.

Dynamics of Centrocestus armatus Transmission in Endemic River in Hyogo Prefecture, Japan.

Centrocestus armatus is an intestinal parasite belonging to the family Heterophyidae. We developed an apparatus for recovering cercariae and clarified the infection dynamics of this parasite. To clarify the circadian rhythm of cercarial shedding in the summer season, we filtrated 30 l of river water every 2 h for 24 h. Cercariae were first detected between 06:00 and 08:00 h, increased over time to reach peak at 16:00 h and decreased thereafter, thus showing a single-peak pattern. In a survey of seasonal change, approximately 200 cercariae were contained in 1 l of river water during the summer season, while none were found during the winter. This cercarial shedding pattern appeared to be related to sunrise/sunset and water/atmosphere temperature. Therefore, we examined whether cercarial shedding was affected by light or temperature changes under laboratory conditions, and confirmed that both light and temperature were important factors for cercarial shedding. Light was a stronger factor than water temperature. Cercarial shedding of C. armatus occurred in response to temperature and light. The change in the number of juvenile metacercariae detected in fish brain corresponded with monthly detection rates of cercariae; however, the incidence of new infections decreased in August. This suggests that Nipponocypris temminkii contains a defense mechanism against new infections that may have hindered the increase in parasite infectivity. These results clarified the smooth infection from the first to the second intermediate host of C. armatus in the endemic river. Throughout the study period, fecal samples were collected from 19 kites, 114 herons, and three unidentified species. However, our results using C. armatus showed a low value of 1% in herons and 5% in kites. The infection dynamics of final host to first intermediate host need to be further investigated.

Soil contamination by parasite eggs in rural village in the Philippines.

Infectious diseases caused by soil-transmitted helminths (STHs) are important diseases of humans, which affect about one third of the world's population. Examination of soil can be used to estimate the risk of STH infection in humans. We carried out this survey to clarify the current status of soil contamination by parasite eggs and to assess the risk of STH infection. During survey periods, we examined soil, faeces, and the lifestyle of residents. Six genera and eight species of parasite eggs including Ascaris lumbricoides, Toxocara cati, Toxocara canis, and Trichuris trichiura were recovered from 85 out of 120 soil samples (71%). Contamination of soil by parasite eggs had spread widely throughout the village, and 50% of eggs recovered had already developed into fertilized eggs. It is remarkable that Ascaris eggs were recovered from inside the houses. Prevalence of STH in school children was 63%. This may indicate that school or preschool children cause soil contamination. Some of the eggs recovered were not only from humans but also from dogs and cats. From the results obtained, the need for health education with regards to zoonoses was revealed because 77% of fertilized Toxocara spp. eggs were detected. We conclude that the risk of STH infection in residents was extremely high, because the soil in this village was highly contaminated by infective parasite eggs.

Toxocara egg soil contamination and its seroprevalence among public school children in Los Baños, Laguna, Philippines.

The soil-transmitted nematode Toxocara sp has little epidemiological information in the Philippines. In this study, we studied the extent of soil contamination with Toxocara eggs and the seroprevalence of Toxocara infection among public school children in Los Baños, Laguna, Philippines. Soil samples were obtained from public schools, backyards, and empty lots in Los Baños to examine for the presence of Toxocara eggs using the modified sucrose flotation technique. Serum samples were obtained from public school children in Los Baños and examined for Toxocara infection using an ELISA test. Of the 200 soil samples, 85 (43%) were positive for Toxocara eggs at a concentration of 1 egg/g of soil. Forty-two percent of soil samples obtained from the public school, 45% of backyard samples, and 40% of empty lot samples were positive. Of the 75 serum samples from children, 37 (49%) were positive for Toxocara infection. There was a positive correlation between Toxocara egg concentration and seroprevalence of Toxocara infection. Results showed a high prevalence of soil contamination and a high seroprevalence of Toxocara infection among children in Los Baños, Laguna, Philippines.