Comparison of Kato Katz, antibody-based ELISA and droplet digital PCR diagnosis of schistosomiasis japonica: Lessons learnt from a setting of low infection intensity (original) (raw)
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Accurate diagnostics for schistosomiasis: a new role for PCR?
Reports in Parasitology, 2015
When it is important to detect schistosome infection with high sensitivity, particularly where local elimination is planned, detection of parasite-specific DNA should be considered as part of the diagnosis. The process of molecular amplification need no longer be considered to be restricted to sophisticated laboratories, but can be used effectively with modern tools in district hospitals or rural clinics and can be adapted for urine if it is used as the DNA source. With schistosomiasis, observation of a typical egg in urine, stool, or biopsy is taken as evidence of infection; point-of-care (POC) tests based on detecting parasite-specific antigens on a simple matrix have made this simpler and effective particularly in rural settings, but like observation of eggs, these methods are liable to give false negative results and thus miss infected cases. These cases are a likely source of parasite eggs to continue the infection cycle. Thus, although convenient, POC tests are unsatisfactory for epidemiological studies and evaluation of mass treatment campaigns. Methods to detect species-specific DNA fragments in fresh urine or in residue after filtration have been described and shown to be more sensitive and specific than specimen-based, serological, or antigen capture diagnosis. Parasite-specific DNA fragments can also be amplified from blood and stool taken from people infected with any of the major schistosomes. However, the use of urine residue after filtering through filter paper as a source of parasite-specific DNA has greatly simplified the process. Urine can be filtered at the POC using disposable plasticware and then paper dried and placed in a plastic sleeve, which is a simple process. If dry, the product is stable and transport is simple and inexpensive, and DNA can be extracted and amplified in a nearby facility set up for the work. If not POC, this is close to POC and quite feasible and processing by PCR or loop-mediated isothermal amplification process will ensure the universal application of this technology.
Journal of microbiological methods, 2016
Schistosomiasis is a chronically debilitating helminth infection with a significant socio-economic and public health impact. Accurate diagnostics play a pivotal role in achieving current schistosomiasis control and elimination goals. However, many of the current diagnostic procedures, which rely on detection of schistosome eggs, have major limitations including lack of accuracy and the inability to detect pre-patent infections. DNA-based detection methods provide a viable alternative to the current tests commonly used for schistosomiasis diagnosis. Here we describe the optimisation of a novel droplet digital PCR (ddPCR) duplex assay for the diagnosis of Schistosoma japonicum infection which provides improved detection sensitivity and specificity. The assay involves the amplification of two specific and abundant target gene sequences in S. japonicum; a retrotransposon (SjR2) and a portion of a mitochondrial gene (nad1). The assay detected target sequences in different sources of schi...
Parasites & Vectors, 2011
Background: The dipstick dye immunoassay (DDIA), recently commercially available in the People's Republic of China (P.R. China), is a rapid and simple test to detect human antibodies against Schistosoma Japonicum. Its performance and utility for screening schistosome infection in low endemic areas is little known. We therefore carried out a cross-sectional survey in seven villages with low endemicity of schistosomiasis in P.R. China and assessed the performance and utility of DDIA for diagnosis of schistosomiasis. Stool samples were collected and examined by the Kato-Katz method and the miracidium hatching technique. Serum samples, separated from whole blood of participants, were tested by DDIA.
Parasites & Vectors, 2011
Background: Schistosomiasis japonica (schistosomiasis) is a zoonosis that can seriously affect human health. At present, the immunodiagnostic assays for schistosomiasis detection are time-consuming and require well-trained personnel and special instruments, which can limit their use in the field. Thus, there is a pressing need for a simple and rapid immunoassay to screen patients on a large scale. In this study, we developed a novel rapid dipstick with latex immunochromatographic assay (DLIA) to detect anti-Schisaosoma japonicum antibodies in human serum. Results: Using latex microspheres as a color probe, DLIA was established to test standard positive and negative sera, in comparison with the classical enzyme-linked immunosorbent assay (ELISA). The sensitivity and specificity of DLIA were 95.10% (97/102) and 94.91% (261/275), respectively. The cross-reaction rates with clonorchiosis, intestinal nematodes, Angiostrongylus cantonensis and paragonimiasis were 0, 0, 0 and 42.11% respectively. All the results showed no significant difference to the ELISA. In field tests, 333 human serum samples from an endemic area were tested with DLIA, and compared with ELISA and Kato-Katz method. There was no significant difference between DLIA and ELISA on positive and negative rates of detection; however, significant differences existed between DLIA and Kato-Katz method, and between ELISA and Kato-Katz method. The kappa value between DLIA and ELISA was 0.90.
PLOS Neglected Tropical Diseases, 2021
Background Elimination and control of Schistosoma japonicum, the most virulent of the schistosomiasis-causing blood flukes, requires the development of sensitive and specific diagnostic tools capable of providing an accurate measurement of the infection prevalence in endemic areas. Typically, detection of S. japonicum has occurred using the Kato-Katz technique, but this methodology, which requires skilled microscopists, has been shown to radically underestimate levels of infection. With the ever-improving capabilities of next-generation sequencing and bioinformatic analysis tools, identification of satellite sequences and other highly repetitive genomic elements for use as real-time PCR diagnostic targets is becoming increasingly common. Assays developed using these targets have the ability to improve the sensitivity and specificity of results for epidemiological studies that can in turn be used to inform mass drug administration and programmatic decision making. Methodology/Princip...
Infectious Diseases of Poverty
Background: Interventions are currently being used against 'infectious diseases of poverty', which remain highly debilitating and deadly in most endemic countries, especially malaria, schistosomiasis, echinococcosis and African sleeping sickness. However, major limitations of current 'traditional' methods for diagnosis are neither simple nor convenient for population surveillance, and showed low sensitivity and specificity. Access to novel technologies for the development of adequate and reliable tools are expressly needed. A collaborative project between African Network for Drugs and Diagnostics Innovation and partner institutions in Africa and China aims to screen suitable serological biomarkers for diagnostic pipelines against these 'diseases of the poor'. Methods: Parasite-specific exposed versus unexposed individuals were screened and sera or urine/stools were collected through case-control studies in China and African countries. Target genes/open reading frames were selected, then will be cloned and cell-free expressed, quantified and immuno-detected. Target antigens/epitopes will be probed and screened with sera from exposed or unexposed individuals using a high-throughput antigen screening platform as the study progresses. The specificity and sensitivity of highly immunoreactive biomarkers will be evaluated as well, using enzyme-linked immunosorbent assays or dipsticks. Discussion: This roadmap explicitly unfolds the integrated operating procedures with focus on malaria and schistosomiasis, for the identification of suitable biomarkers that will aid the prioritization of diagnostics for population use. However, there is need to further validate any new diagnostic through comparison with standard methods in field deployable tests for each region. Our expectations for the future are to seek regulatory approval and promote the use of diagnostics in endemic areas.
Pathogens, 2022
Schistosomiasis japonica caused by the trematode flukes of Schistosoma japonicum was one of the most grievous infectious diseases in China in the mid-20th century, while its elimination has been placed on the agenda of the national strategic plan of healthy China 2030 after 70 years of continuous control campaigns. Diagnostic tools play a pivotal role in warfare against schistosomiasis but must adapt to the endemic status and objectives of activities. With the decrease of prevalence and infection intensity of schistosomiasis in human beings and livestock, optimal methodologies with high sensitivity and absolute specificity are needed for the detection of asymptomatic cases or light infections, as well as disease surveillance to verify elimination. In comparison with the parasitological methods with relatively low sensitivity and serological techniques lacking specificity, which both had been widely used in previous control stages, the molecular detection methods based on the amplifi...
Research Square, 2024
Background Schistosomiasis, a neglected tropical disease, is a major helminth disease in terms of morbidity and mortality that affects more than 200 million people worldwide. This study aimed to use real-time PCR (RT‒PCR) for the detection of Schistosoma sp. DNA in both urine and faeces samples before and after praziquantel (PZQ) treatment, and the results were compared with those of conventional PCR and microscopic detection of schistosome eggs to evaluate treatment efficacy. Methods Both urine and stool samples were collected from three hundred and eighty seven (387) study participants aged between 3 and 25 years before and after (3 weeks and 8 weeks) treatment with PZQ in Dumbi communities, Nigeria. On the treatment day, all participants who tested positive after microscopic examination (29) in the community were treated with a single dose of 40 mg/kg PZQ. DNA was isolated from 50 samples (urine) that tested positive using microscopy in preparation for molecular analysis. Microsoft Excel 2016 and SPSS version 20.0 statistical software were used for data analysis. Results Utilising diagnostic methods, microscopy detected Schistosoma haematobium eggs in 7.5% (29) of the urine samples collected before treatment, whereas RT‒PCR amplified DNA in 39.8% (154) of the same samples, and no eggs were detected in the stool samples analysed. Among the diagnostic methods for 50 samples that were used for comparative analysis, RT‒PCR had the highest positive detection of 80%, followed by conventional PCR (72%), haematuria (64%) and microscopy (58%). Compared with microscopy, RT‒PCR and conventional PCR both provided lower estimates of cure rates. Conclusions The results of this study revealed that RT‒PCR and conventional PCR are significantly more sensitive than microscopy for detecting and evaluating infection incidence, which is an important aspect of epidemiological studies. The RT‒PCR-based detection technique can be especially useful in circumstances of lower intensity or prevalence of infection, a condition for which the parasitological diagnosis shows a well-proven limitation of its sensitivity.
Infectious Diseases of Poverty
Background Zoonotic schistosomiasis, caused by Schistosoma japonicum, remains a major public health problem in the Philippines. This study aimed to evaluate the commercially available rapid diagnostic point-of-care circulating cathodic antigen (POC-CCA) test in detecting individuals infected with S. japonicum in a human cohort from an endemic area for schistosomiasis japonica in the Philippines. Methods Clinical samples were collectedin 18 barangays endemic for S. japonicum infection in Laoang and Palapag municipalities, Northern Samar, the Philippines, in 2015. The presence of CCA in filter-concentrated urine samples (n = 412) was evaluated using the commercial kits and the results were converted to images, which were further analyzed by ImageJ software to calculate R values. The diagnostic performance of the immunochromatographic POC-CCA test was compared using the Kato-Katz (KK) procedure, in-house enzyme-linked immunosorbent assays (ELISAs) and droplet digital (dd) PCR assays as...
Real-time PCR diagnosis of Schistosoma japonicum in low transmission areas of China
Infectious diseases of poverty, 2018
Schistosomiasis in the People's Republic of China (PRC) can be traced back to antiquity. In the past 60 years, the Chinese government has made great efforts to control this persistent disease with elimination slated by 2020 through the implementation of a comprehensive control strategy. This strategy aims to reduce the role of bovines and humans as sources of infection as a pre-requisite for elimination through transmission interruption. The goal of elimination will be achievable only by the implementation of a sustainable surveillance and control system, with sensitive diagnosis a key feature so that the true disease burden is not underestimated. Currently used diagnostics lack the necessary sensitivity to accurately determine the prevalence of Schistosoma japonicum infection in areas with low infection intensities. It is of critical importance to find and treat people and to identify animals with low-level infections if the National Control Programme for China is to achieve sc...