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Wisetmora A, Artchayasawat A, Laummaunwai P, Pitaksakulrat O, Wattanawong O, Boonmars T. Formalin-fixed stool improves the performance of the Kato-Katz method. Vet World 2024; 17:99-107. [PMID: 38406352 PMCID: PMC10884569 DOI: 10.14202/vetworld.2024.99-107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/14/2023] [Indexed: 02/27/2024] Open
Abstract
Background and Aim Parasitic infections are a public health problem worldwide, including in Thailand. An epidemiological survey for helminthiasis based on stool examination uses the Kato-Katz method as recommended by the World Health Organization. Limitations of this method include the need for fresh stool, time requirement, and lack of quality control. The aim of this study was to enhance the efficiency of the Kato-Katz technique using formalin and glycerol solutions and to implement specimen preparation in fieldwork. Materials and Methods For the Kato-Katz method, stool samples were divided into formalin-fixed and unfixed groups at various time points and processes. Fresh echinostome eggs were added to each stool group. Incubation with glycerol increased the clearing process. Each group was observed and photographed using a light microscope. Parasite eggs were imaged and compared using the standard Kato-Katz method. Results Visualization of echinostome eggs from formalin-fixed stool slides was significantly better than that from unfixed stool slides (p < 0.01). Stool samples fixed for 7 days retained normal echinostome eggs morphology. Incubation with glycerol for 1 h resulted in increased Kato-Katz performance by digesting the stool content and enhancing egg observation. Moreover, the results of the Kato-Katz method using fixed and fixed stool plus glycerol for natural helminth infection showed good quality of Opisthorchis viverrini and Taenia egg visualization and normal morphology with a clear background of slides. Conclusion Formalin-fixed stool could be more suitable than fresh stool for the Kato-Katz method.
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Affiliation(s)
- Ampas Wisetmora
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
- Division of General Communicable Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, 11000, Thailand
| | - Atchara Artchayasawat
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Porntip Laummaunwai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Opal Pitaksakulrat
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Oranard Wattanawong
- Office of Diseases Prevention and Control 4 Saraburi, Ministry of Public Health, Saraburi, 18120, Thailand
| | - Thidarut Boonmars
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
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Fernández-Soto P, Fernández-Medina C, Cruz-Fernández S, Crego-Vicente B, Febrer-Sendra B, García-Bernalt Diego J, Gorgojo-Galindo Ó, López-Abán J, Vicente Santiago B, Muro Álvarez A. Whip-LAMP: a novel LAMP assay for the detection of Trichuris muris-derived DNA in stool and urine samples in a murine experimental infection model. Parasit Vectors 2020; 13:552. [PMID: 33160406 PMCID: PMC7648965 DOI: 10.1186/s13071-020-04435-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/29/2020] [Indexed: 01/25/2023] Open
Abstract
Background Trichuris trichiura (human whipworm) infects an estimated 477 million individuals worldwide. In addition to T. trichiura, other Trichuris species can cause an uncommon zoonosis and a number of human cases have been reported. The diagnosis of trichuriasis has relied traditionally on microscopy. Recently, there is an effort to use molecular diagnostic methods, mainly qPCR. LAMP technology could be an alternative for qPCR especially in low-income endemic areas. Trichuris muris, the causative agent of trichuriasis in mice, is of great importance as a model for human trichuriasis. Here, we evaluate the diagnostic utility of a new LAMP assay in an active experimental mouse trichuriasis in parallel with parasitological method by using stool and, for the first time, urine samples. Methods Stool and urine samples were collected from mice infected with eggs of T. muris. The dynamics of infection was determined by counting the number of eggs per gram of faeces. A LAMP based on the 18S rRNA gene from T. muris was designed. Sensitivity and specificity of LAMP was tested and compared with PCR. Stool and urine samples were analysed by both LAMP and PCR techniques. Results Trichuris muris eggs were detected for the first time in faeces 35 days post-infection. LAMP resulted specific and no cross-reactions were found when using 18 DNA samples from different parasites. The detection limit of the LAMP assay was 2 pg of T. muris DNA. When testing stool samples by LAMP we obtained positive results on day 35 p.i. and urine samples showed amplification results on day 20 p.i., i.e. 15 days before the onset of T. muris eggs in faeces. Conclusions To the best of our knowledge, we report, for the first time, a novel LAMP assay (Whip-LAMP) for sensitive detection of T. muris DNA in both stool and urine samples in a well-established mice experimental infection model. Considering the advantages of urine in molecular diagnosis in comparison to stool samples, should make us consider the possibility of starting the use urine specimens in molecular diagnosis and for field-based studies of human trichuriasis where possible. Further studies with clinical samples are still needed.![]()
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Affiliation(s)
- Pedro Fernández-Soto
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain.
| | - Carlos Fernández-Medina
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Susana Cruz-Fernández
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Beatriz Crego-Vicente
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Begoña Febrer-Sendra
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Juan García-Bernalt Diego
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Óscar Gorgojo-Galindo
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Julio López-Abán
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Belén Vicente Santiago
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Antonio Muro Álvarez
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain.
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[Profiles of intestinal polyparasitism in a community of the Colombian Amazon region]. BIOMEDICA 2017; 37:368-377. [PMID: 28968014 DOI: 10.7705/biomedica.v37i3.3395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Intestinal parasite infections and polyparasitism are highly prevalent in the most vulnerable populations of developing countries due to environmental, biological and social determinants common in the transmission of parasites. Children between 1 and 15 years of age are the most affected population. OBJECTIVE To describe the prevalence and profiles of intestinal polyparasitism in 1 to 15 year-old children from native communities in the Colombian Amazon region. MATERIALS AND METHODS We used a non-probability sampling of 300 children between 1 and 15 years of age from several rural settlements and the main urban area of Puerto Nariño, Amazonas, Colombia, who participated voluntarily in the study. We obtained fecal samples that were analyzed by the direct method (0.85% saline solution-lugol) and the Kato-Katz technique. The most prevalent polyparasitism profiles were identified using Cohen's kappa coefficient with a 95% confidence interval. RESULTS The prevalence of polyparasitism, defined as the presence of at least two intestinal pathogenic parasites, was 84% (95 % CI: 79.35-87.96). Polyparasitism by two or three of the following parasites: Ascaris lumbricoides, Trichuris trichiura, Blastocystis sp., Ancylostoma duodenale and Necator americanus from the Ancylostomatidae family, and Entamoeba histolytica, E. dispar and E. moshkovskii of the Entamoeba complex, had the highest prevalence. CONCLUSION Several intestinal polyparasitism profiles were found, although in most cases fewer than six parasites were involved. Better prevalence estimations and identification of determinant factors will allow to priorize and direct resources to control these infections.
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Knudson-Ospina A, Skantria-Salazar Á, Hember Tabares J, Restrepo CA, Ruiz MÁ, López MC. Preservación de huevos de Necator americanus con acetato de sodio-ácido acético-formalina (SAF). Estudio de caso. REVISTA DE LA FACULTAD DE MEDICINA 2017. [DOI: 10.15446/revfacmed.v65n2.58693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Introducción. La técnica de Kato Katz es el método recomendado para realizar el recuento de huevos en materia fecal y determinar la intensidad parasitaria por helmintos. La calidad de los resultados se ve afectada por la tardanza en el procesamiento de la muestra, por lo que se requiere de preservantes que faciliten la lectura posterior a las 24 horas de recolección de la muestra.Objetivo. Demostrar validez de la solución con acetato de sodio-ácido acético-formalina (SAF) como preservante de huevos de Necator americanus por medio del estudio de un caso clínico.Materiales y métodos. Descripción de caso clínico con diagnóstico de parásitos intestinales por coprológico, intensidad de la infección por la técnica de Kato Katz, evaluación de la presencia de huevos N. americanus por la técnica de Kato Katz durante 10 meses en muestra preservada en SAF y determinación de especie de Uncinaria sp.por qPCR.Resultados. Los huevos de N. americanus se conservan de manera adecuada en morfología durante los primeros cinco meses.Conclusiones. A fin de ejecutar la técnica de Kato Katz, la fijación con SAF demostró ser adecuada para el mantenimiento de la intensidad parasitaria y morfología de los huevos de N. americanus en un período de hasta cinco meses.
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Abstract
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.
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