A comparative study of the TF-Test®, Kato-Katz, Hoffman-Pons-Janer, Willis and Baermann-Moraes coprologic methods for the detection of human parasitosis

Modifications to the parasitological technique of Rugai increase the diagnostic sensitivity for strongyloidiasis

Strongyloidiasis is a neglected tropical disease caused mainly by Strongyloides stercoralis, a nematode that can persist for decades in the human host with a very low parasitic burden and without specific symptoms. Hence, it is difficult to diagnose and control. Larval concentration and culture methods with fecal samples show higher sensitivity for the diagnosis of Strongyloides-infected individuals; however, these techniques are not routinely used, primarily due to the challenges associated with processing a substantial volume of fecal samples. In the current study, we comparatively evaluated the sensitivity and applicability of modifications made to the Rugai parasitological method for the diagnosis of strongyloidiasis in fecal samples of experimentally infected rats and in 68 individuals from an urban community close to Maceió, Brazil. The presence and quantity of parasite larvae in the feces were comparatively evaluated using different parasitological techniques. In the experimental model, we demonstrated that the modified Rugai technique (RMOD) allowed for significantly higher recovery of larvae than the original Rugai technique (RO). Moreover, the sediment was cleaner and easier to evaluate using optical microscopy. Compared to other parasitological techniques, such as agar-plate culture (A-PC) and spontaneous sedimentation (SS), the RMOD technique showed higher sensitivity in the detection of larvae in all infected groups and presented comparatively better performance, especially in rats with a low parasite burden. In the human population, among the 68 stool samples evaluated, Strongyloides larvae were detected in the feces of six individuals with an estimated prevalence of 8.82%. However, the performance of each parasitological method was remarkably different. SS identified Strongyloides larvae in only two individuals and A-PC in three, whereas RMOD was able to identify six infected individuals, resulting in sensitivities of 33.3%, 50%, and 100%, respectively. In conclusion, the modifications introduced to the Rugai technique resulted in improved sensitivity for the detection of Strongyloides spp. infections, especially in stool samples with a low parasite burden, in comparison with other routinely used parasitological techniques.

First identification of Strongyloides stercoralis infection in a pet dog in Argentina, using integrated diagnostic approaches

BACKGROUND

Strongyloides stercoralis is a soil-transmitted intestinal nematode with a complex life cycle that primarily affects humans, non-human primates, dogs, and occasionally cats. This study presents, to the best of our knowledge, the first case of S. stercoralis infection and its genotyping in a domestic dog from Argentina.

METHODS

The patient was a female wired-haired Teckel dog exhibiting recurrent coughing. Coproparasitological analysis using the Baermann technique revealed the presence of rhabditiform larvae morphologically compatible with S. stercoralis. To confirm this finding, molecular diagnosis (18S ribosomal RNA) and analysis of the cox1 gene were performed.

RESULTS

We identified a haplotype (HP20) that has previously only been related to S. stercoralis infection in dogs, but was found in the present study to be highly related to the haplotype (HP16) of a zoonotic variant and divergent from those previously described from human patients in Argentina. Furthermore, unlike in human cases following treatment with ivermectin, the dog was negative after moxidectin treatment according to polymerase chain reaction of the sampled faeces.

CONCLUSIONS

This case report shows the importance of further investigation into potential transmission events and prevalences of S. stercoralis in dogs and humans in South America. The results reported here should also encourage future work that examines different scenarios of infection with S. stercoralis in dogs and humans with the aim of integrating clinical management, diagnosis, treatment and follow-up strategies in the quest for new approaches for the treatment of this disease in animals and humans. The findings support the adoption of a One Health approach, which recognizes the interconnectedness between animal and human health, in addressing parasitic infections such as strongyloidiasis.

[Schistosomiasis, soil-transmitted helminthiases and sanitation in Latin America and the Caribbean: a systematic reviewRelación entre la prevalencia de esquistosomiasis y geohelmintiasis y las condiciones sanitarias en América Latina y el Caribe: una revisión sistemática]

Objective

To investigate the relationship between the prevalence of schistosomiasis and soil-transmitted helminthiasis with variables related to access to water, sanitation and solid waste in Latin American and Caribbean (LAC) countries.

Method

A systematic review was performed in the LILACS, PubMed, Web of Science, and SciELO databases. Studies published between 1950 and August 2021, with an ecological design and a focus on population groups (states, municipalities and/or districts), having the prevalence of infection by Schistosoma mansoni, Ancylostoma sp., Necator americanus, Ascaris lumbricoides or Trichuris trichiura as primary variable and access to water, sewage and/or solid waste as explanatory variables were included. Open access articles with full text available in English, Spanish, or Portuguese were considered. The risk of bias and the quality of the studies were assessed according to the Joanna Briggs Institute manual.

Results

Of 2 714 articles, nine were eligible, published between 1994 and 2021 and covering 22 LAC countries and 14 350 municipalities. All articles had moderate methodological quality. Environmental variables indicated an association between water supply and solid waste collection with schistosomiasis; water supply with ascariasis, trichuriasis and hookworm; and sewage with ascariasis and hookworm. Except for one article, which had regional coverage for LAC, all the others were developed in Brazil.

Conclusion

There is a clear need to expand research on the association between household and collective health conditions and parasitic diseases for all endemic countries in LAC to support environmental strategies to control these diseases.

Effect of environmental factors in reducing the prevalence of schistosomiasis in schoolchildren: An analysis of three extensive national prevalence surveys in Brazil (1950-2018)

BACKGROUND

Over seven decades, Brazil has made admirable progress in controlling schistosomiasis, and a frequent question about the explanation for this reduction refers to the effect of improving environmental factors in the country. This article seeks to identify factors related to the change in the epidemiological situation of schistosomiasis mansoni infection by analyzing three national prevalence surveys conducted since 1950.

METHODOLOGY/PRINCIPAL FINDINGS

This is an ecological study analyzing an unbalanced panel of data based on national surveys and considering the municipality as the unit of analysis. The sample consisted of 1,721 Brazilian municipalities, in which a total of 1,182,339 schoolchildren aged 7-14 were examined during the three periods corresponding to each survey (1947-1953, 1975-1979, and 2010-2015). The percentage of municipalities with zero cases of schistosomiasis was: 45.4%, 54.2% and 73.7%, respectively for those periods. A zero-inflated Poisson regression model, with fixed and random effects, was fitted to assess the association between candidate factors and disease prevalence using a significance level of 5%. There was a significant decrease in disease prevalence between the first and last periods analyzed (RR 0.214, CI 0.184-0.249), with a protective association with access to sanitation (RR 0.996, CI 0.994-0.998), urbanization (RR 0.991, CI 0.989-0.993), and living in own households (RR 0.986, CI 0.983-0.989); and an inverse association with piped water supply (RR 1.010, CI 1.008-1.011).

CONCLUSION

The findings of this study indicate a decrease in the prevalence of schistosomiasis over seven decades in schoolchildren from the analyzed Brazilian municipalities, associated with environmental factors and social conditions. The increased access to piped water in the municipalities apparently triggers other ways of contact with unsafe water bodies, generating new transmission routes and suggesting the need for a systemic approach concerning contact with water.

From past to present: opportunities and trends in the molecular detection and diagnosis of Strongyloides stercoralis

Strongyloides stercoralis is a soil-transmitted helminth that is mainly found in the tropical and subtropical regions and affects approximately 600 million people globally. The medical importance of strongyloidiasis lies in its capacity to remain asymptomatic and chronically unnoticed until the host is immunocompromised. Additionally, in severe strongyloidiasis, hyperinfection syndrome and larva dissemination to various organs can occur. Parasitological techniques such as Baermann-Moraes and agar plate culture to detect larvae in stool samples are the current gold standard. However, the sensitivity might be inadequate, especially with reduced worm burden. Complementing parasitological techniques, immunological techniques including immunoblot and immunosorbent assays are employed, with higher sensitivity. However, cross-reactivity to other parasites may occur, hampering the assay's specificity. Recently, advances in molecular techniques such as polymerase chain reaction and next-generation sequencing technology have provided the opportunity to detect parasite DNA in stool, blood, and environmental samples. Molecular techniques, known for their high sensitivity and specificity, have the potential to circumvent some of the challenges associated with chronicity and intermittent larval output for increased detection. Here, as S. stercoralis was recently included by the World Health Organization as another soil-transmitted helminth targeted for control from 2021 to 2030, we aimed to present a review of the current molecular techniques for detecting and diagnosing S. stercoralis in a bid to consolidate the molecular studies that have been performed. Upcoming molecular trends, especially next-generation sequencing technologies, are also discussed to increase the awareness of its potential for diagnosis and detection. Improved and novel detection methods can aid in making accurate and informed choices, especially in this era where infectious and non-infectious diseases are increasingly commonplace.

Effects of hypertonic solutions on two species of human intestinal parasites during fecal examination

Aim: Ova and parasite examination by flotation requires hypertonic solutions, which can damage the egg and cyst membranes, leading to false negatives. The authors investigated the harmful effects of ZnSO₄ and C₁₂H₂₂O₁₁ solutions on the ova and parasite examination. Materials & methods: The authors processed samples using the Three Fecal Test technique. Aliquots were floated in different pH levels, temperatures and solution densities. Results: Densities above 1.12 g/ml led structures to collapse after 6-10 min. pH neutralization of the ZnSO₄ solution did not prevent the parasites from changing. Conclusion: All structures were altered when standard methods were performed. To delay collapse, the parasite floating under 5 °C is highly desirable.

Advantages and Limitations of Microscopy and Molecular Detections for Diagnosis of Soil-transmitted Helminths: An Overview

World Health Organization (WHO) reported that over 1.5 billion people are infected by soil-transmitted helminths (STH) worldwide in sub-Saharan Africa, the United States of America, China, and East Asia. Heavy infections and polyparasitism are associated with higher morbidity rates, and the patients are exposed to increased vulnerability to other diseases. Therefore, accurate diagnosis followed by mass treatment for morbidity control is necessary.STH diagnosis commonly involves the microscopic observation of the presence of the STH eggs and larvae in the faecal samples. Furthermore, molecular approaches are increasingly utilised in monitoring and surveillance as they show higher sensitivity. Their capability to differentiate hookworm species is an advantage over the Kato-Katz technique. This review discusses the advantages and limitations of microscopy and various molecular tools used for STH detection.

The application of the FLOTAC technique for detection of helminth eggs of medical and veterinary importance in soil samples

The FLOTAC technique was initially developed to detected infective stages of parasites in animal and human feces. Recently, its applicability has been extended by the use in pastures and vegetables for human consumption. However, its use for the detection of parasites in the soil has never been investigated. In this study, we assessed the performance of the FLOTAC and compared with centrifugal flotation (CFT) and spontaneous sedimentation (SST) techniques. A total of 50 soil samples were collected from the Metropolitan region of Recife, Northeastern Brazil. Initially, samples were standardized, and then assessed in duplicate by the FLOTAC, CFT and SST. Cohen's kappa coefficient, sensitivity, specificity, positive and negative predictive values, and accuracy of the FLOTAC, CFT and SST were assessed using the results of the combination of all three techniques as gold standard. Out of all analyses performed, in 96% (48/50), helminth eggs of parasites were detected. In particular, 96% (48/50) of samples analysed through the FLOTAC technique, 76% (38/50) for CFT and 28% (14/50) for SST were positive. Nematode eggs of the Ancylostomatidae and Ascarididae families were those mostly detected in this study. Overall, the FLOTAC presented high values of sensitivity, demonstrating that this method may also be employed for detection of parasites in soil samples. This study opens new possibilities for the use of the FLOTAC technique, highlighting its role as a potential tool for detecting environmental contamination by parasites of medical and veterinary importance.

The diagnosis of human and companion animal Strongyloides stercoralis infection: Challenges and solutions. A scoping review

Strongyloidiasis is the infection caused by soil-transmitted nematodes of Strongyloides species, infecting humans and some animals. Strongyloides stercoralis is the species with most clinical and epidemiological relevance in humans and dogs, due to its high prevalence and its capacity of inducing a life-threatening hyperinfection. Diagnosis of strongyloidiasis is challenging, due to the absence of a single reference standard test with high sensitivity and specificity, which also hampers the estimation of the accuracy of other diagnostic tests. In this chapter, we review the deployment and performance of the parasitological, immunological, molecular tests for the diagnosis of strongyloidiasis in humans and in dogs. Further, we comment the available evidence from genotyping studies that have addressed the zoonotic potential of S. stercoralis. Finally, we discuss the use of different diagnostic methods in relation to the purpose (i.e., screening, individual diagnosis, inclusion in a clinical trial) and the setting (endemic/non-endemic areas) and report the accuracy figures reported by systematic reviews on either parasitological, serological or molecular techniques published in literature.

Small islands as potential model ecosystems for parasitology: climatic influence on parasites of feral cats

The influence of climate on parasite distribution has been demonstrated in different regions worldwide. Despite its small size, Gran Canaria (Canary Islands, Spain) constitutes a 'biodiversity laboratory' due to the huge climatic differences between municipalities. Feral cats may represent a threat to biodiversity due to their predatory behaviour. In addition, they may be a source of pathogens zoonotic to humans. To study the climatic/seasonal influence and prevalence of feral cat parasites throughout the island, a total of 290 stool samples from 29 feral cat colonies were analysed following standard concentration protocols (sodium chloride, formol-ether and zinc sulphate). In total, 13 feline parasitic taxa were found, with the most common species being Ancylostoma spp., which, together with Toxocara spp., Toxoplasma gondii and Giardia spp., are considered a concern for human health. Nematodes were the most common parasites in all areas. Nematodes and protozoans were significantly more prevalent in temperate mild (75.0% and 30.0%) than in dry desert areas (29.3% and 18.7%). In contrast, cestodes were significantly more prevalent in dry desert than in temperate mild areas (26.0% and 13.3%). Only protozoans exhibited statistically significant seasonal patterns, mostly in the wet season. Data reported in this study endorse the usage of small and diverse islands such as Gran Canaria to study the climatic influence on parasitic communities in wild/feral animals. Cat colonies require better management to reduce their threat to endemic wildlife, domestic animals and public health, being invasive species that harbour zoonotic parasites.

Ineffectiveness of TF-Test® and Coproplus® Methods in Strongyloides stercoralis Infection Diagnosis

PURPOSE

S. stercoralis diagnosis is currently performed by parasitological methods, mainly by Baermann-Moraes (BM), although Agar Plate Culture (APC) presents a higher sensitivity. New techniques, such as TF-Test® and Coproplus® have been suggested as more practical alternatives. The aim of this study was to evaluate the sensitivity of TF-Test® and Coproplus®, compared with APC, BM and Spontaneous Sedimentation (SS) methods.

METHODS

One-hundred and forty male alcoholic patients, who provided three stools samples collected on alternate days, were included in this study. The most frequently found parasite was S. stercoralis, 20% (28/140), and the most sensitive method was APC, 96.4% (27/28), followed by BM, 89.3% (25/28) and SS, 57.1% (16/28). TF-Test® and Coproplus® presented a sensitivity of 46.4 (13/28) and 39.3% (11/28), respectively. In samples with a parasitic load of 1-10 larvae/g of feces, which occurred in 39.3% (11/28) of the infected patients, both the TF-Test® and Coproplus® methods demonstrated sensitivities of 18.2% (2/11), while APC and BM methods reached a sensitivity of 100% (11/11) (p < 0.05). For other intestinal helminth infections, TF-Test® and Coproplus® sensitivities were 22.2 (4/18) and 11.1% (2/18), respectively, this being lower than the SS, 66.7% (12/18) (p < 0.05). On the other hand, for protozoa infection diagnosis, TF-Test® and Coproplus® presented the highest sensitivities, 62.2 (46/74) and 43.2% (32/74), respectively.

CONCLUSION

TF-Test® and Coproplus® methods presented the lowest sensitivities for S. stercoralis and other helminth infection diagnosis; therefore, they can be indicated for use in parasitological diagnosis, only when associated with other more effective methods of helminth identification.

Veterinary monitoring of gastrointestinal parasites in European bison, Bison bonasus designated for translocation: Comparison of two coprological methods

It is important to monitor the level of parasitic loads in herds of European bison and to identify threats early enough to prevent their spread to other populations or species. The aim of the present study was to compare the detection sensitivity of two fecal flotation techniques, viz. the modified Willis method (WM) with centrifugation and modified McMaster flotation technique (MM), in the diagnostics of gastrointestinal parasites of European bison before the translocation of animals.

Out of 166 feces samples, Eimeria spp. oocysts (84.3% in WM and 71.1% in MM) and Trichostrongylidae eggs (82.5% in WM and 53.6% in MM) predominated. These were accompanied by eggs from Capillaria spp. (prevalence: 13.9% in WM and 3.61% in MM), Nematodirus spp. (prevalence: 18.1% in WM and 4.8% in MM) and Trichuris spp. (prevalence: 12.7% in WM and MM) were identified. The lowest prevalence was noted for cestode eggs of Moniezia spp. (5.4% in WM and 3.0% in MM).

The Willis method yielded a higher prevalence of eggs and oocysts than the modified McMaster method, and hence has a higher probability of detecting parasitic structures than the modified McMaster method, especially in cases of very low levels of invasion.

As the two methods yield consistent results, it is recommended to use the Willis method for diagnosis of internal parasite infection in European bison. This test offers more sensitive method than McMaster technique of detecting the presence of low levels of a variety of parasite eggs and oocysts in feces, while also being inexpensive and adaptable to field work.

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Methods yield similar relative prevalence.

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Higher prevalence of eggs/oocysts in Willis than McMaster.

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Very low prevalence may not be detected by the McMaster method.

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Proposed formulas are provided for converting prevalence between methods.

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The Willis method is recommended over the McMaster method.

Automated Diagnostics: Advances in the Diagnosis of Intestinal Parasitic Infections in Humans and Animals

The increasingly close proximity between people and animals is of great concern for public health, given the risk of exposure to infectious diseases transmitted through animals, which are carriers of more than 60 zoonotic agents. These diseases, which are included in the list of Neglected Tropical Diseases, cause losses in countries with tropical and subtropical climates, and in regions with temperate climates. Indeed, they affect more than a billion people around the world, a large proportion of which are infected by one or more parasitic helminths, causing annual losses of billions of dollars. Several studies are being conducted in search for differentiated, more sensitive diagnostics with fewer errors. These studies, which involve the automated examination of intestinal parasites, still face challenges that must be overcome in order to ensure the proper identification of parasites. This includes a protocol that allows for elimination of most of the debris in samples, satisfactory staining of parasite structures, and a robust image database. Our objective here is therefore to offer a critical description of the techniques currently in use for the automated diagnosis of intestinal parasites in fecal samples, as well as advances in these techniques.

Comparison of diagnostic performance of single and multiple fecal sampling in the detection of soil-transmitted helminths in school-aged children

Soil-transmitted helminths (STHs) are widely distributed globally and India is a significant contributor to the overall global burden of the disease. Microscopic methods like Kato-Katz (K-K) thick smear and direct smear microscopy by wet mount (DSM) are widely used for STH diagnosis due to their ease in performance. Still, low sensitivity proves to be a significant limitation of these methods. This study explores the diagnostic performance of two and three consecutive-day stool samples compared to the common practice of single stool sample examination. We observed that the three consecutive-day stool examination technique increased overall helminth positivity from 12% to 16.3% in K-K and 11.5-15.9% in DSM, indicating that multiple sampling can diagnose intestinal helminthiasis more accurately. A significant increase in the intensities of hookworms (by 37.5%; p value: 0.001) and Trichuris trichiura (by 47.8%; p value: 0.037) (measured in terms of fecal egg count) was also observed. The methods undertaken in the current study are comparable in detecting the helminths as the marginal increase in positivity by K-K (16.32% vs. 15.86%) was statistically insignificant.

Diversity, geographical distribution, and prevalence of Entamoeba spp. in Brazil: a systematic review and meta-analysis

The genus Entamoeba includes a variety of widely distributed species adapted to live in the digestive tracts of humans and a large variety of animals of different classes. The objective of this study was to investigate the prevalence, distribution, and molecular epidemiology of Entamoeba spp. in different classes of hosts in Brazil. Studies that analyzed hosts from several classes, including humans and domestic, wild, or captive animals, were considered. The pooled prevalence of Entamoeba spp. was calculated using the random-effects model. A total of 166 studies on humans and 16 on animals were included. The prevalence of Entamoeba spp. in the Brazilian population was 22% (95% CI: 21–24). The state with the highest prevalence was Paraiba with 72%, followed by Federal District with 53%, and Rondonia with 50%. In immunocompromized patients, the prevalence was 18%, and cancer (36%) was the most prevalent cause of immunosuppression. The prevalence of Entamoeba spp. in animal hosts was 12% (95% CI: 7–17). Captive wild animals and domestic farm animals showed the highest prevalence, with 16% and 15%, respectively. The species found more often were E. coli (86.5%), E. dispar (7.9%), and E. histolytica (3.1%). In conclusion, a high prevalence (22%) of Entamoeba spp. was found in the Brazilian population, with a prevalence of up to 50% mainly in the northern, northeastern, and central-western regions. The pathogenic species E. histolytica is distributed in most Brazilian regions, with significant prevalence percentages. Among animals, unidentified Entamoeba species were most prevalent in mammals.

The Prevalence of Soil-Transmitted Helminths and Associated Risk Factors among School Children at Sekela Primary School, Western Ethiopia

Soil-transmitted helminth (STH) infections are a major public health problem in tropical and developing countries in relation to poverty, inadequate hygiene, and sanitation. This study was aimed at assessing the status of STH and associated risk factors among school children in the case of Sekela primary school. Cross-sectional descriptive studies were conducted in May 2019 and from 384 children, both males and females of equal proportion were used. A stool sample was collected randomly and examined in the laboratory under a microscope. The quantitative data were analyzed using SPSS version 20. The difference was considered statistically significant at p value = 0.05. The overall STH infections observed in the study area were about 25.78% and were moderate transmission. The predominant helminth was A. lumbricoides (9.86%) followed by hookworm 6.25%, T. trichiura 5%, H. nana 3.10%, and H. diminuta 1.56%. Infections were generally more in males than females, in which 15.36% males and 10.41% females. In the case of age group, age groups between 7-8 years were more infected (13.28%). Infection rate decreases with increasing ages. Multivariate logistic regression analysis result indicated that wearing shoes, hand washing practice, family member, and residence were found to be associated risk factors for STH infections. Being urban dwellers and having family members with less than 2 children were found to be preventive. Lack of latrine, playing barefoot, untrimmed fingernail, eating raw vegetables, and absence of hand washing were major risk factors. In conclusion, the study showed that there was moderate transmission of infection among the study participants. Community-based health education using media, morbidity control through deworming, and improving sanitation should be strengthened as a measurement to control the transmission rate.

Prevalence of soil transmitted helminths in school-aged children, Colombia, 2012-2013

Background

This study aims to establish the prevalence of soil-transmitted helminth (STH) intestinal infections, nutritional status, and anemia in school children aged 7 to 10 years old in the biogeographic provinces of Colombia in 2012–2013. STH prevalence in the country has not been described within the last 30 years and it is needed in order to establish policies its control in the country.

Methodology

National Survey of STH in school-aged children with a multistage stratified probability sampling was conducted. The overall prevalence and intensity of STH infection, as well as for each parasite, (A. lumbricoides, T. trichiura and hookworms) were calculated for the country and for each of the nine biogeographic provinces.

Principal findings

Stool samples were collected from 6045 children in eight out of nine biogeographic provinces. The combined prevalence of STH in the country was 29.6%. T. trichiura was the most prevalent helminth (18.4%), followed by A. lumbricoides (11.3%), and hookworms (6.4%). For A. lumbricoides and hookworms, the highest prevalence values were found in the Amazonía province (58.0% and 35.7%, respectively). Regarding STH intensity, most cases showed moderate intensity (41.3%) for A. lumbricoides, and light intensity, for T. trichiura and hookworms. The national prevalence of anemia in school-aged children was 14.2%, lowest in the Nor-Andina province (3.5%), and highest in the Territorios Insulares oceánicos del Caribe province (45.1%).

Significance

Colombia has a moderate risk of STH infection in school-aged populations, with considerable variation in the prevalence values among the biogeographic provinces. Like any public health issue, this problem should be handled with a comprehensive approach that involves deworming programs and strategies for STH control according to the specific epidemiological and socioeconomic conditions and sanitation service coverage in each biogeographic province. The program should be further supported by intersectoral action to improve living conditions, particularly the excreta disposal, promoted at municipality levels.

STH infection (infection by A. lumbricoides, T. trichiura, and hookworms) are endemic in Colombia; however, its prevalence in the country has not been described within the last 30 years. This study determines the prevalence and intensity of STH infections, nutritional status, and anemia in children, using multistage stratified probability sampling. The prevalence result of all STH at national level was 29.6%. T. trichiura was the most prevalent (18.4%), followed by A. lumbricoides (11.3%), and hookworms (6.4%). Comparing the biogeographic provinces (eco-epidemiological zones), Amazonía had the highest STH prevalence. A large spatial variation was found in STH prevalence by province. The study shows that STH infection remains a national public health problem, which requires intervention through nationwide strategies using a comprehensive inter-programmatic approach and prioritizing high-risk areas. These strategies should aim at improving the living conditions associated with the infection while being supported by large-scale anthelmintic chemotherapy.

Enteric parasitic infections in children and dogs in resource-poor communities in northeastern Brazil: Identifying priority prevention and control areas

The aim of this study was to determine the prevalence and risk factors of the main enteric parasitic infections that affect children and dogs in the municipality of Ilhéus, Bahia, Brazil; and to identify the geopolitical areas that should receive priority interventions to combat them. Between March and November 2016, fecal samples of 143 dogs and 193 children aged 1 month to 5 years were collected in 40 rural and semirural communities using a systematic sampling approach, stratified by district. Samples were collected by legal guardians of the children and / or dog owners. Eggs, larvae, cysts and oocysts of parasites were concentrated by centrifugal-flotation and centrifugal-sedimentation, and acid-resistant staining was used to visualize parasites. One hundred and thirty-two children (68.4%), 111 dogs (77.6%) and 199 (73.7%) dog fecal samples collected from streets were parasitized. Giardiasis, cryptosporidiosis, amoeba infections and hookworm were the most frequent infections in all studied populations, in addition to trichuriasis in dogs and ascaridiasis in children. A predominance of Giardia and hookworms was observed in children and dogs, respectively. The coastal districts of Aritaguá, Olivença and the main district had a higher parasitic diversity and overlapping of important potential zoonotic infections. Age over one year (p<0.001), adjusted OR = 3.65; 95% CI = 1.86-7.16) and income below the minimum monthly salary (p = 0.02, adjusted OR = 2.78, 95% CI = 1.17-6.59) were the main factors associated with intestinal parasitic infections in children and dogs, respectively. The coastal districts of Aritaguá and Olivença and the main district should be prioritized through enteric disease control programs, and the factors associated with infections must be considered in the design of health interventions in these districts. The integration between affirmative income actions and investments to improve the health infrastructure of these communities may work more effectively than current preventive measures to combat enteric parasites.

A historical review of the techniques of recovery of parasites for their detection in human stools

Since the early 20th century, the detection of intestinal parasites has improved with the development of several techniques for parasitic structures recovery and identification, which differ in sensitivity, specificity, practicality, cost, and infrastructure demand. This study aims to review, in chronological order, the stool examination techniques and discuss their advantages, limitations, and perspectives, and to provide professionals and specialists in this field with data that lays a foundation for critical analysis on the use of such procedures. The concentration procedures that constitute the main techniques applied in routine research and in parasitological kits are a) spontaneous sedimentation; b) centrifugation-sedimentation with formalin-ethyl acetate; and c) flotation with zinc sulfate solution. While selecting a technique, one should consider the purpose of its application and the technical-operational, biological, and physicochemical factors inherent in the procedures used in stool processing, which may restrict its use. These intrinsic limitations may have undergone procedural changes driven by scientific and technological development and by development of alternative methods, which now contribute to the improvement of diagnostic accuracy.

Epidemiology of human giardiasis in Romania: A 14 years survey

Giardia spp. is the most common intestinal protozoan (causing gastrointestinal illness) and the most frequent cause of parasitic gastroenteritis in humans and animals worldwide. The aim of this study was to highlight new data in a specific area regarding clinical presentation and epidemiological prevalence over a long period of time. Patients (a total number of 54,623 patients) admitted in a tertiary center for infectious diseases serving a county for a period of 14 years were tested for infection with Giardia. Positive cases were recorded through analyzing the clinical complaints, the month of incidence and the demographic area from which the patients came from. Longitudinal trends have been evaluated. The incidence of giardiasis among the tested patients was 4.47%. A decreasing trend was observed regarding the annual incidence. Patients between the ages of 15 and 44 presented most commonly giardiasis, especially those from urban areas and women. The most common symptoms are loss of appetite (71.24%) and abdominal pain (69.07%). The highest monthly incidence was quoted in July (10.65%), August (10.49%) and June (10.20%). This epidemiological study allows a better knowledge of the infection with Giardia spp. It gives the long-term changes in demographic characteristics of the infected patients in a specific area and the monthly incidence.

Automated Diagnosis of Canine Gastrointestinal Parasites Using Image Analysis

Because canine intestinal parasites are considered cosmopolitan, they carry significant zoonotic potential to public health. These etiological agents are routinely diagnosed using microscopic examination commonly used because of its low cost, simple execution, and direct evidence. However, there are reports in the literature on the poor performance of this test due to low to moderate sensitivity resulting from frequent errors, procedures and interpretation. Therefore, to improve the diagnostic efficiency of microscopic examination in veterinary medicine, we developed and evaluated a unique new protocol. This system was tested in a study involving four genera of highly prevalent canine intestinal parasites in an endemic region in São Paulo state, Brazil. Fecal samples from 104 animals were collected for this research. The new protocol had a significantly higher (p < 0.0001) number of positive cases on image data, including parasites and impurities, and was elaborate to test them with the TF-GII/Dog technique, with a moderate agreement and Kappa index of 0.7636. We concluded that the new Prototic Coproparasitological Test for Dogs (PC-Test Dog) allowed a better visualization of the parasitic structures and showed a favorable result for the diagnosis of intestinal parasites in dogs.

Intestinal Parasites, Anemia and Nutritional Status in Young Children from Transitioning Western Amazon

Young children are particularly vulnerable to the chronic sequelae of anemia, including poor nutritional status. The aim of this study was to assess intestinal parasitic-infections and nutritional status (anemia and linear growth) in preschool children living in contemporary Amazonian communities. A cross-sectional study measured children’s intestinal parasites and hair-Hg (HHg)—biomarkers of fish consumption, hemoglobin levels, and growth (anthropometric Z-scores). Children came from traditional-living families (Itapuã), and tin-mining settlements (Bom Futuro) representing current transitioning populations. It covered 937 pre-school children (from 1 to 59 months of age) from traditional (247) and immigrant tin-mining families (688). There was a high prevalence of intestinal polyparasitic-infection in children from both communities, but mild anemia (hemoglobin concentrations) and moderate (chronic) malnutrition were more frequent in children from traditional families than in children from tin-mining settlers. Children from traditional families ate significantly more fish (HHg mean of 4.3 µg/g) than children from tin-mining families (HHg mean of 2.3 µg/g). Among traditional villagers, children showed a significant correlation (r = 0.2318; p = 0.0005) between hemoglobin concentrations and HHg concentrations. High rates of parasitic infection underlie the poverty and attendant health issues of young children in the Brazilian Amazon. The intestinal parasite burden affecting poor Amazonian children resulting from unsafe water, lack of sanitation and poor hygiene is the most urgent environmental health issue.

Socioeconomic and parasitological aspects in Quilombola communities in two of the oldest municipalities in Brazil

Objective To carry out a socioeconomic, demographic and parasitological evaluation of quilombola communities in two of the oldest municipalities in Brazil.Material and Methods Between December 2015 and June 2016, of the total of 231 residents of the communities, socioeconomic questionnaires were applied and fecal samples collected from 150 individuals were analyzed by spontaneous sedimentation method and the Kato-Katz method.Results It was observed that 95.3% (n=143) of the interviewees had piped water at their residence, and 76% (n=114) came from wells or springs; 85.3% (n=128) reported that the toilet drain was made in a rudimentary septic tank and 59.3% (n=89) reported having litter buried or burned, showing precarious conditions in basic sanitation. Still on socioeconomic aspects, 80.7% (n=121) of the individuals reported having access to the public health service. Parasitological tests were positive for 48% (n=72) of the analyzed samples, and 25% (n=18) had two or more parasites. The most frequent organism in the study population was the commensal Entamoeba coli (55.6%, n=40), followed by Ascaris lumbricoides (19.4%, n=14) and the commensal Endolimax nana (16.7%, n=12). The Poisson regression showed an increase of 1.59 in the prevalence of parasites for individuals who do not have access to the public health service, when compared to those who have access to these services.Conclusions The results indicate the need to implement public health measures in order to reduce, prevent and treat the parasitological condition of the population to obtain better conditions and quality of life.

Use of the aqueous biphasic system as an alternative for concentration of Ascaris lumbricoides eggs, with non-toxic separation of faecal residues and fats

OBJECTIVES

Human enteroparasites are considered a serious public health problem in underdeveloped countries located in world regions with tropical, subtropical and equatorial climates. These parasites are commonly diagnosed by the Parasitological Examination of Faeces (PEF), performed by conventional techniques and/or commercial kits that result in tests with low-to-moderate sensitivity, due to the use of destructive chemical solvents to parasite structures, and to present excess adipose substance and digestive residues in their microscopic slides. In order to improve the efficacy of these tests/examinations, this study aimed to investigate a new alternative for the PEF, with the use of Aqueous Biphasic System (ABS).

METHODS

For this, four ABSs containing poly (ethylene glycol), PEG (PEG-4000 and PEG-6000), dipotassium phosphate and sodium citrate at different concentrations in the biphasic systems were evaluated with faecal samples containing eggs of Ascaris lumbricoides.

RESULTS

The ABS consisting of PEG-4000 and dipotassium phosphate, at concentrations of 55% w/w and 20% w/w, respectively, achieved 100% satisfactory results compared to the conventional TF-Test technique in terms of preservation and concentration of A. lumbricoides eggs, with adequate separation of digestive residues, without using a centrifuge or chemical solvents that may cause harm to the parasites.

CONCLUSIONS

This study presents ABS as a new low-cost technical principle for the detection of parasite eggs in PEF. The new technique is simple, fast, non-toxic, not harmful to the parasite and does not require a centrifuge.

Prevalence and potential risk factors for gastrointestinal parasitic infections in children in urban Bissau, Guinea-Bissau

BACKGROUND

Gastrointestinal (GI) parasitic infections cause significant morbidity and mortality in tropical and subtropical countries. We aimed to investigate the prevalence of GI parasitic infections in children from Bissau, Guinea-Bissau and to identify the possible risk factors for these infections.

METHODS

We performed an observational study on two comparable cohorts of children 2-15 y of age: one study covering health care-seeking children (n=748) and one study covering children from the background population (n=851). A total of 1274 faecal samples from the two cohorts were investigated for parasites by microscopy and the risk factors for infection were identified by logistic regression.

RESULTS

Intestinal parasitic infections were found in 54.8% of health care-seeking children and 55.5% of children from the background population. Helminth infections were more common among health care-seeking children and were mainly due to hookworms. Pathogenic protozoa included Entamoeba histolytica/dispar and Giardia lamblia. The risk factors for infections included increasing age, household crowding and poor sanitation and water supply.

CONCLUSIONS

We found a high prevalence of intestinal parasites among both health care-seeking children and children from the background population. Compared with previous studies, we found a decreasing prevalence of intestinal helminths. This study further identifies potential risk factors for infections, including inadequate sanitation and water supply.

Highly specific and sensitive anti-Strongyloides venezuelensis IgY antibodies applied to the human strongyloidiasis immunodiagnosis

Due to the epidemiological problem of the neglected condition of human strongyloidiasis, rapid and effective diagnosis is extremely important, with the development of new diagnostic tools being essential to reduce infections and chronic cases. Avian immunoglobulin Y (IgY) technology is an alternative for antibody production that has high specificity and profitability. This study aimed to produce and fractionate IgY antibodies from the egg yolks of hens that were immunized with the total antigenic extracts of Strongyloides venezuelensis infectious filariform larvae (iL3) and parthenogenetic females (pF). IgY antibodies were then evaluated by their recognition of antigenic proteins, evolutive helminth forms, and serological diagnosis of human strongyloidiasis by the detection of immune complexes in serum samples. Egg yolks were fractionated to obtain IgY antibodies by thiophilic interaction chromatography. Immune complex detection in serum samples showed diagnostic values for anti-iL3 IgY and anti-pF IgY antibodies at 95.56% and 88.89% sensitivity and 95.56% and 91.11% specificity, respectively. Therefore, IgY technology is a promising tool for the detection of blood circulating Strongyloides antigens, with possible application as a serological diagnostic method.

Prevalence of schistosomiasis mansoni in indigenous Maxakali villages, Minas Gerais, Brazil

Intestinal parasitic infections are a common health problem among Amerindian populations and schistosomiasis represents one of the most prevalent diseases in Maxakali people. The Kato-Katz is the diagnostic method recommended by WHO for epidemiological studies; however, one of the technique's limitations is the failure to detect parasites in individuals with low parasite load. The aim of this study was to establish the prevalence of Schistosoma mansoni in indigenous Maxakali villages, evaluating the TF-Test® performance for diagnosis compared to the Kato-Katz technique. Stool samples from 545 individuals were processed by the TF-Test® (1 sample) and Kato-Katz (1 slide). The positivity rate for S. mansoni by Kato-Katz was 45.7%. The rate by the TF-Test® was 33.2%, and 51.9% by the combined parasitological techniques. The amplitude of parasite load was 24 to 4,056 eggs per gram of feces (epg), with a geometric mean of 139 epg. The co-positivity, co-negativity, and accuracy values by TF-Test® in relation to Kato-Katz were 59.0%, 88.5%, and 75.0%, respectively. The agreement between these techniques was moderate (k=0.486) as determined by the kappa index. Thus, the results of this study demonstrated that the performance of Kato-Katz was superior (p <0.05) to that of TF-Test® in the detection of S. mansoni. The combination of TF-Test® and Kato-Katz resulted in an increased positivity rate of S. mansoni, demonstrating the high risk of infection to which indigenous populations are exposed and the importance of the implementation of control strategies in Maxakali villages.

High prevalence of enteroparasites in children from Ribeirão Preto, São Paulo, Brazil

Objective:

To determine the prevalence of intestinal parasites and possible associated factors.

Method:

Cross-sectional epidemiological study of 962 children (3-12-years) from an area within the scope of a basic health unit in Ribeirão Preto, São Paulo, Brazil. Data were collected by home interviews and three-sample stool analysis and evaluated with the chi-square and Fisher's exact tests (p<0.05).

Results:

The prevalence of intestinal parasites was significantly high (57.5%). Giardia lamblia was the most prevalent (50.8%), followed by Ascaris lumbricoides (17.8%), Entamoeba histolytica, Hymenolepis nana, Entamoeba coli and Enterobius vermiculares (5.6-7.3%) and other parasites of lower prevalence, such as Schistosoma japonicum (1%) and Schistosoma mansoni (0.5%). No statistically significant associations were detected between prevalence and the risk factors analyzed.

Conclusion:

Since the area presents good conditions of environmental sanitation, health education programs should be implemented that emphasize hygiene procedures for the hands and for food and water to be consumed by the population.

Immunomodulation of allergic response in children and adolescents: What we can learn from lymphatic filarial infection

BACKGROUND

Although it is well known that allergic diseases involve a strong Th2 immune response, with production of high levels of specific IgE allergen, knowledge on the association between filarial infection and allergies, among paediatric patients is scarce.

OBJECTIVE

To evaluate the allergic response patterns in cases of filarial infection by comparing peripheral eosinophils, total IgE levels, immediate hypersensitivity and cytokine levels in children and adolescents in Brazil.

METHODS

This was an exploratory study with three groups: (I) with filarial infection and without allergic diseases; (II) without filarial infection and with allergic diseases; and (III) without filarial infection and without allergic diseases. The prick test and specific IgE tests for aeroallergens were performed using five antigens. Peripheral eosinophils and total IgE were also evaluated. IL-4 and IL-5 were determined using whole-blood culture stimulated by three antigens.

RESULTS

Eosinophilia and elevated levels of total IgE (≥400IU/dl) were observed in all groups. The prick test was positive in 56.6% of the cases. Group I presented hypersensitive responses similar to the allergic disease groups. In the whole-blood culture stimulated by Dermatophagoides pteronyssinus, average IL-4 production did not differ significantly among the groups, but IL5 production resulting from stimulation was greater in the allergic disease groups (p<0.05).

CONCLUSIONS

The allergic response pattern in group with filarial infection was similar to that of the groups with and without allergic diseases, but the response to IL-5 in the culture stimulated by D. pteronyssinus was an exclusive characteristic of the allergic group.

Combination of five diagnostic tests to estimate the prevalence of hookworm infection among school-aged children from a rural area of colombia

BACKGROUND

Public health programs for the control of soil-transmitted helminthiases require valid diagnostic tests for surveillance and parasitic control evaluation. However, there is currently no agreement about what test should be used as a gold standard for the diagnosis of hookworm infection. Still, in presence of concurrent data for multiple tests it is possible to use statistical models to estimate measures of test performance and prevalence. The aim of this study was to estimate the diagnostic accuracy of five parallel tests (direct microscopic examination, Kato-Katz, Harada-Mori, modified Ritchie-Frick, and culture in agar plate) to detect hookworm infections in a sample of school-aged children from a rural area in Colombia.

METHODS AND RESULTS

We used both, a frequentist approach, and Bayesian latent class models to estimate the sensitivity and specificity of five tests for hookworm detection, and to estimate the prevalence of hookworm infection in absence of a Gold Standard. The Kato-Katz and agar plate methods had an overall agreement of 95% and kappa coefficient of 0.76. Different models estimated a sensitivity between 76% and 92% for the agar plate technique, and 52% to 87% for the Kato-Katz technique. The other tests had lower sensitivity. All tests had specificity between 95% and 98%. The prevalence estimated by the Kato-Katz and Agar plate methods for different subpopulations varied between 10% and 14%, and was consistent with the prevalence estimated from the combination of all tests. The Harada-Mori, Ritchie-Frick and direct examination techniques resulted in lower and disparate prevalence estimates. Bayesian approaches assuming imperfect specificity resulted in lower prevalence estimates than the frequentist approach.

Comparison of parasitological techniques for the diagnosis of intestinal parasitic infections in patients with presumptive malabsorption

Intestinal parasitic infections still remain a public health problem, overall in tropical and subtropical regions. Frequently, patients with malabsorption syndrome can be infected with intestinal parasites, independent that they could be the etiological agents. To compare three coproparasitological techniques Paratest^®, Ritchie and direct wet mount for the diagnosis of intestinal parasitic infections in patients with suspected malabsorption syndrome. A descriptive cross sectional survey was carried out in 82 patients with presumptive symptoms of intestinal malabsorption. Three consecutive stool samples were collected from every patient and they were analyzed by three coproparasitological techniques. The degree of agreement was almost perfect when all parasitological techniques were compared for all protozoan infections. Nevertheless, the agreement between Paratest^® and Ritchie's methods was slightly lower because this last method was superior for intestinal infections with commensals. The technique of Ritchie showed 100% of sensitivity for protozoa infections in general. However, the direct wet mount and the Paratest^®, showed lower sensitivity. When all techniques were compared only for infections with no pathogenic protozoa, the Paratest^® had the lowest sensitivity, and less predictive value for negatives. Ritchie's method showed a higher superiority than Paratest^® for the diagnosis of intestinal protozoa infections in this group of patients. We would recommend the evaluation of new techniques in local conditions before to decide the introduction in the public health network of laboratories.

Comparative study of five techniques for the diagnosis of canine gastrointestinal parasites

Differences in the efficacy of diagnostic techniques employed in the parasitological examination of feces are a limiting factor of this laboratory procedure in the field of Veterinary Parasitology. To verify advances in this type of examination in dogs, we conducted a study using a new technique (TFGII/Dog). Fifty naturally infected dogs were housed in individual stalls, and their feces were evaluated comparatively using this technique and four other conventional techniques. The TFGII/Dog showed high levels of sensitivity and efficiency, surpassing the diagnostic accuracy of the other techniques with a kappa concordance index of 0.739 (Substantial), as opposed to 0.546 (Moderate), 0.485 (Moderate), 0.467 (Moderate), and 0.325 (Fair) of the Spontaneous-Sedimentation, Centrifugal-Flotation in Saturated Zinc Sulfate Solution, Centrifugal-Flotation in Saturated Sugar Solution, and Spontaneous-Flotation in Saturated Sodium Chloride Solution techniques, respectively. The combination of positive results of all techniques comprises eight genera of parasites, with Ancylostoma spp. predominating among helminths, and Cystoisospora spp. among protozoa. The TFGII/Dog technique showed better diagnostic performance, and can therefore be considered an important tool for optimizing the results of laboratory routines and for the control of canine gastrointestinal parasites.

Validation of a new technique to detect Cryptosporidium spp. oocysts in bovine feces

Due to its important zoonotic potential, cryptosporidiosis arouses strong interest in the scientific community, because, it was initially considered a rare and opportunistic disease. The parasitological diagnosis of the causative agent of this disease, the protozoan Cryptosporidium spp., requires the use of specific techniques of concentration and permanent staining, which are laborious and costly, and are difficult to use in routine laboratory tests. In view of the above, we conducted the feasibility, development, evaluation and intralaboratory validation of a new parasitological technique for analysis in optical microscopy of Cryptosporidium spp. oocysts, called TF-Test Coccidia, using fecal samples from calves from the city of Araçatuba, São Paulo. To confirm the aforementioned parasite and prove the diagnostic efficiency of the new technique, we used two established methodologies in the scientific literature: parasite concentration by centrifugal sedimentation and negative staining with malachite green (CSN-Malachite) and Nested-PCR. We observed good effectiveness of the TF-Test Coccidia technique, being statistically equivalent to CSN-Malachite. Thus, we verified the effectiveness of the TF-Test Coccidia parasitological technique for the detection of Cryptosporidium spp. oocysts and observed good concentration and morphology of the parasite, with a low amount of debris in the fecal smear.

Parasite species of the endangered Iberian wolf (Canis lupus signatus) and a sympatric widespread carnivore

Parasites have a profound impact on wildlife population dynamics. However, until some years ago, studies on the occurrence and prevalence of wildlife parasites were neglected comparatively with the studies on humans and domestic animals. In this study, we determined the parasite prevalence of two sympatric wild canids: the endangered Iberian wolf (Canis lupus signatus) and the widespread red fox (Vulpes vulpes), in central Portugal. From November 2014 to July 2015, fresh fecal samples from both species were collected monthly in several transects distributed throughout the study area. All samples were submitted to several coprological techniques. In total, 6 helminth parasites (Crenosoma vulpis, Angiostrongylus vasorum, Toxocara canis, Trichuris vulpis, Ancylostomatidae, Toxascaris leonina), and a protozoa (Balantidium coli) were identified based on size and morphology. The red fox was infected by seven different parasites while the Iberian wolf was infected by four. All parasites present in wolf were also present in the red fox. C. vulpis had the higher prevalence in red fox, while Ancylostomatidae were the most prevalent parasites in wolf. To our knowledge, this is the first study in this isolated subpopulation of the Iberian wolf. Our results show that both carnivores carry parasites that are of concern as they are pathogenic to humans and other wild and domestic animals. We suggest that surveillance programs must also include monitoring protocols of wildlife; particularly endangered species.

HIGH PREVALENCE OF Blastocystis spp. INFECTION IN CHILDREN AND STAFF MEMBERS ATTENDING PUBLIC URBAN SCHOOLS IN SÃO PAULO STATE, BRAZIL

After a gastroenteritis outbreak of unknown etiology in the municipality of Sebastião da Grama, SãoPaulo, Brazil, we conducted a parasitological survey to establish the epidemiological profile of enteroparasitosis in children and staff members attending the public urban schools in operation in town. The cross-sectional study evaluated 172 children aged 11 months to 6 years old and 33 staff members aged 19 to 58 years old. Overall, 96 (55.81%) children and 20 (60.61%) staff members were mono-parasitized, while 58 (33.72%) children and 4 (12.12%) workers were poly-parasitized. Protozoa (88.37%; 72.73%) was more prevalent than helminthes (3.48%; 0%) in children and staff members respectively.Blastocystis spp. was the most prevalent parasite in children (86.63%) and staff members (66.67%). The age of 1 year old or less was found to be associated with increased prevalence of giardiasis [OR = 13.04; 95%CI 2.89-58.91; p = 0.00] and public garbage collection was identified as a protective factor against intestinal helminth infections [OR = 0.06; 95%CI 0.00-0.79; p = 0.03]. Although most of the children tested positive for Blastocystis spp. and also presented clinical signs/symptoms (62.2%), this association was not statistically significant [OR = 1.35; 95%CI 0.53-3.44; p = 0.51]. Intestinal parasites still represent a public health concern and this study underscores the importance of further investigations to better understand the pathogenic role of Blastocystis spp.

Intestinal helminth coinfection is associated with mucosal lesions and poor response to therapy in American tegumentary leishmaniasis

The most severe clinical form of American tegumentary leishmaniasis (ATL) due to Leishmania braziliensis is mucosal leishmaniasis (ML), characterized by destructive lesions in the facial mucosa. We performed a retrospective cohort study of 109 ATL patients from Rio de Janeiro State, Brazil, where ATL is caused by L. braziliensis, to evaluate the influence of intestinal parasite coinfections in the clinical course of ATL. Parasitological stool examination (PSE) was performed with samples from all patients by the sedimentation, Kato-Katz and Baermann-Moraes methods. The diagnosis of ATL was made from lesion biopsies by direct observation of amastigotes in Giemsa-stained imprints, isolation of Leishmania promastigotes or histopathological examination. All patients were treated with meglumine antimoniate. Patients with positive PSE had a frequency of mucosal lesions significantly higher than those with negative PSE (p<0.005). The same was observed for infections with helminths in general (p<0.05), with nematodes (p<0.05) and with Ascaris lumbricoides (p<0.05), but not for protozoan infections. Patients with intestinal parasites had poor response to therapy (therapeutic failure or relapse) significantly more frequently than the patients with negative stool examination (p<0.005). A similar difference (p<0.005) was observed between patients with positive and negative results for intestinal helminths, but not for intestinal protozoa. Patients with positive PSE took significantly longer to heal than those with negative PSE (p<0.005). A similar difference was observed for intestinal helminth infections (p<0.005), but not for protozoan infections. Our results indicate a deleterious influence of intestinal helminth infections in the clinical course of ATL and evidence for the first time an association between ML and these coinfections, particularly with nematodes and A. lumbricoides.

Human Ascariasis: Diagnostics Update

Soil-transmitted helminths (STHs) infect over one billion people worldwide. Ascariasis may mimic a number of conditions, and individual clinical diagnosis often requires a thorough work-up. Kato-Katz thick smears are the standard detection method for Ascaris and, despite low sensitivity, are often used for mapping and monitoring and evaluation of national control programmes. Although increased sampling (number of stools) and diagnostic (number of examinations per stool) efforts can improve sensitivity, Kato-Katz is less sensitive than other microscopy methods such as FLOTAC®. Antibody-based diagnostics may be a sensitive diagnostic tool; however, their usefulness is limited to assessing transmission in areas aiming for elimination. Molecular diagnostics are highly sensitive and specific, but high costs limit their use to individual diagnosis, drug - efficacy studies and identification of Ascaris suum. Increased investments in research on Ascaris and other STHs are urgently required for the development of diagnostic assays to support efforts to reduce human suffering caused by these infections.

TF-Test Modified: New Diagnostic Tool for Human Enteroparasitosis

Intestinal parasitosis is highly prevalent worldwide, being among the main causes of illness and death in humans. Currently, laboratory diagnosis of the intestinal parasites is accomplished through manual technical procedures, mostly developed decades ago, which justifies the development of more sensitive and practical techniques. Therefore, the main objective of this study was to develop, evaluate, and validate a new parasitological technique referred to as TF-Test Modified, in comparison to three conventional parasitological techniques: TF-Test Conventional; Rugai, Mattos & Brisola; and Helm Test/Kato-Katz. For this realization, we collected stool samples from 457 volunteers located in endemic areas of Campinas, São Paulo, Brazil, and statistically compared the techniques. Intestinal protozoa and helminths were detected qualitatively in 42.23% (193/457) of the volunteers by TF-Test Modified technique, against 36.76% (168/457) by TF-Test Conventional, 5.03% (23/457) by Helm Test/Kato-Katz, and 4.16% (19/457) by Rugai, Mattos & Brisola. Furthermore, the new technique presented "almost perfect kappa" agreement in all evaluated parameters with 95% (P < 0.05) of estimation. The current study showed that the TF-Test Modified technique can be comprehensively used in the diagnosis of intestinal protozoa and helminths, and its greater diagnostic sensitivity should help improving the quality of laboratory diagnosis, population surveys, and control of intestinal parasites.

A rapid diagnostic test for Schistosomiasis mansoni

This article presents an improvement to the Kato-Katz (KK) method, making it faster and more efficient for the visualisation of fertile eggs in stool samples. This modified KK method uses sodium acetate formalin as a fixative and reveals the intensity of infection in less than 1 h, reducing the diagnostic time without increasing the cost. This modified method may contribute to future epidemiological studies in both hospitals and the field due to its rapid and precise diagnostic, which allow for immediate treatment.

Diagnosis of the pinworm Syphacia muris in the Wistar rat Rattus norvegicus

This study aimed to compare three qualitative parasitological methods for the diagnosis of Syphacia muris infection in 30 Wistar rats (Rattus norvegicus) infected naturally. Methods of spontaneous sedimentation (Hoffman, Pons and Janer, or HPJ) and spontaneous flotation (Willis) for faecal samples and a method of taping (Graham) were performed and compared. The Graham and Willis methods were more sensitive than the HPJ method (P< 0.05). The Graham method was able to detect S. muris eggs in 100% of the samples. Eggs were detected in 83% and 60% of the samples using the Willis and HPJ methods, respectively. Method choice is important for screening for parasites of rats kept under laboratory conditions, as accurate diagnosis helps prevent future environmental contamination and infection. We concluded that the Graham method was the most efficient of those tested in this study for detection of S. muris infection in rats. This method is also rapid, inexpensive and practical, and should be implemented as a necessary measure for infection control.

Reducing occurrence of Giardia duodenalis in children living in semiarid regions: impact of a large scale rainwater harvesting initiative

Background

In Brazil, about two million people living in rural semiarid regions were benefited with the construction of rainwater cement cisterns, as an initiative from the program “One Million Cisterns” (P1MC). Nevertheless, few epidemiological studies have been conducted to assess health risks or protection effects associated with consumption of this water source. The aim of this study was to evaluate whether access to rainwater harvesting cisterns is associated with the decrease in the occurrence of Giardia duodenalis infections in children, compared to other children living in households supplied by other water sources.

Methodology/Principal Findings

A quasi-experimental study with two concurrent cohorts was developed in two rural municipalities of the semiarid region of Brazil. A sample of 664 children, aged between 4 months and 5 years old, was followed up, of which 332 had access to rainwater cisterns (cistern group) and 332 did not, having water supplied from alternative sources (comparison group). In a period of approximately one year (2010) intestinal parasites were investigated in feces three times. The prevalence of G. duodenalis in children from the cistern group ranged from 4.8 to 10.5%, while the prevalence in the comparison group ranged from 7.6 to 16.7%. Multivariate analysis (GEE) showed a higher risk of G. duodenalis infection in children who did not have access to rainwater cisterns, when compared to children who did (OR 1.72; 95% CI 1.14–2.59). The other variables associated with G. duodenalis infection were: number of rooms per house (OR 0.89; 95% CI 0.80–0.99); family income (OR0.48; 95% CI 0.26–0.88); birth order (OR 1.72; 95% CI 1.17–2.51); preterm children (OR 1.70; 95% CI 1.19–2.43); and improper hand hygiene prior to food preparation (OR 4.78; 95% CI 1.95–11.76).

Conclusions/Significance

Ownership of a rainwater cistern is associated with a lower prevalence of G. duodenalis infection in children after adjustment for environmental and family-related factors. Nevertheless, the study suggests the necessity to complement physical interventions with actions related to personal and domestic hygiene to enable further reductions in parasite infections affecting mainly the underprivileged populations.

Currently, rainwater harvesting cisterns built up through the “One Million Cisterns” Program, coordinated by the Brazilian Government, represents the most important public policy for water supply in the rural semiarid region of Brazil. Despite the extensive use of this water provision, few studies have been performed to assess the associated health impact. To assess such impact, this study investigated factors associated with the occurrence of Giardia duodenalis (protozoan closely related to the ingestion of contaminated water) in children aged between 4 months and five years old. Two distinct groups of children, one with access to rainwater cisterns (cistern group) and the other without cisterns, with water supplied from alternative sources, including rivers, springs or dams (comparison group) were followed up for approximately one year. It was observed that the risk occurrence of G. duodenalis prevalence was greater in children from the comparison group, when compared with those from the cistern group, indicating that the odds of infection by this parasite were 1.72 times greater for comparison group children. In conclusion, the study showed health benefits related to rainwater cisterns, but also identified that other complementary sanitation interventions are needed to minimize the risk of disease in populations with limited access to drinking water.

Comparison of the performance of two spontaneous sedimentation techniques for the diagnosis of human intestinal parasites in the absence of a gold standard

Performance evaluation of diagnostic tests is critical in the search for accurate diagnoses. A gold standard test is usually absent in parasitology, thus rendering satisfactory assessment of diagnostic accuracy difficult. Moreover, reliability (assessed by the study of repeatability) is a rarely studied characteristic of diagnostic tests. This study compared and evaluated the performance (repeatability, concordance and accuracy) of the spontaneous sedimentation technique (SST) and the Paratest for the diagnosis of Giardia lamblia, Entamoeba histolytica complex, Blastocystis spp., Ascaris lumbricoides, hookworm, Trichuris trichiura and Calodium hepaticum. Fecal samples of 143 individuals were separated into three replicates for each test. Concordance and homogeneity of the results between replicates of each test and between tests were evaluated. Proportions of positives, sensitivity and specificity were estimated using a Bayesian Latent Class Model. High repeatability of both tests was found for the detection of intestinal parasites, except for Blastocystis spp. and hookworm. Concordance between tests was generally high (concordance correlation coefficient, 0.72-0.88), except for Blastocystis spp., hookworm and T. trichiura. The Paratest detected more cases of Blastocystis spp. and fewer of hookworm than the SST. The tests were quite discordant in the detection of T. trichiura. A low sensitivity (39.4-49.2% for SST, 35.8-53.8% for Paratest) and a high specificity (93.2-97.2%) were found for both tests. The Paratest presented a slightly higher sensitivity for the diagnosis of Blastocystis spp. (53.8%), and SST did so for hookworm (49.2%). This is the first study on repeatability and accuracy (using a Bayesian approach) of two spontaneous sedimentation techniques. These results suggest underdiagnosis of little dense parasitic forms due to technical limitations in both tests. We conclude that the combined study of repeatability, concordance and accuracy is a key strategy for better evaluation of the performance of tests and is also useful for the identification of technical limitations.

Diagnosis of human nematode infections

Many hundreds of millions of people throughout the world are infected by nematodes found in the intestine or tissues with a high prevalence in developing countries. Despite their frequency and morbidity, these infections, which may affect migrants and travelers, remain difficult to diagnosis even in developed countries. This is primarily due to the variety of clinical signs often associated with a lack of highly sensitive and specific diagnostic tools. Parasitological diagnosis is often difficult to achieve and can neither be applied during the pre-patent period nor for parasitic impasses. Serological diagnosis is frequently hampered by a lack of specificity due to cross-reaction with others helminthes. Molecular biology methods still require optimization. The diagnostic approach applied by a clinician of a suspected nematode infection is based on a vast set of data including patient history and way of life, clinical examination, non-specific biological tests and, when available, specific diagnostic tests.

Ion-exchange protocol to obtain antigenic fractions with potential for serodiagnosis of strongyloidiasis

The aim of this study was to fractionate and partially characterize the antigenic extract of filariform larvae of Strongyloides venezuelensis in ion-exchange resin diethylaminoethyl sepharose (DEAE), to obtain antigenic fractions potentially applicable in immunoassays. Somatic antigen (SA) and its fractions DEAE S1 and DEAE S2 - which interacted with the resin - were evaluated by 1-dimensional electrophoresis to obtain protein profiles. SA and its fractions were tested in serum samples for IgG detection by ELISA. Serum samples (n = 155) were analysed: 50 from strongyloidiasis patients (G1), 55 from patients with other parasitic infections (G2) and 50 from healthy volunteers. Sensitivity (Se), specificity (Sp), area under curve (AUC) and likelihood ratios (LR) were calculated. The DEAE S2 fraction provided a high diagnostic value for IgG detection (Se 92·0%, Sp 91·4%, AUC 0·981, LR+ 10·75, LR − 0·09). In conclusion, the DEAE S2 fraction would probably be a source of immunodominant polypeptides for IgG detection in human strongyloidiasis serodiagnosis.