Development and evaluation of a rapid diagnostic immunochromatographic device to detect antibodies in sera from intestinal capillariasis cases

Improved diagnostic sensitivity of human strongyloidiasis using point-of-care mixed recombinant antigen-based immunochromatography

Strongyloidiasis is a neglected tropical disease that can cause fatal complications due to hyperinfection and disseminated strongyloidiasis in immunocompromised patients. We used two Strongyloides stercoralis recombinant antigenic proteins, L3NieAg.01 (NIE) and IgG-immunoreactive antigen (SsIR), to develop the recombinant antigen-based immunochromatography test (ICT) kit. We constructed and compared kits using either the NIE (NIE ICT kit) or the SsIR (SsIR ICT kit) antigens and a kit using a mixture of both (NIE-SsIR ICT kit) for detection of anti-Strongyloides IgG antibody in human serum samples. Serum samples from normal healthy individuals (Group I, n = 40), proven strongyloidiasis patients (Group II, n = 100), and those with other parasitic infections (Group III, n = 154) were evaluated. Sensitivity and specificity were 81.0% and 84.0% for the NIE ICT kit, 89.0% and 83.5% for the SsIR ICT kit, and 95.0% and 90.2% for the NIE-SsIR ICT kit, respectively. The NIE-SsIR ICT kit provided the best diagnostic results; it can supplement stool examination for clinical diagnosis and can be used to screen for asymptomatic S. stercoralis infection in people at risk in endemic areas. The NIE-SsIR ICT kit can also be used in large-scale sero-epidemiological investigations in endemic areas without the need for additional facilities or ancillary supplies.

High Prevalence of Intestinal Capillariasis in Chronic Diarrhea Patients in Thailand: Serological Screening Using a Rapid Lateral-Flow Immunochromatographic Assay

Intestinal capillariasis is an emerging fish-borne helminthic disease caused by the round worm Capillaria philippinensis. Chronic infection may lead to death if the disease is misdiagnosed and inappropriate treatment is given. We used a rapid lateral-flow immunochromatographic test for screening of intestinal capillariasis in patients with chronic diarrhea. We screened 292 chronic diarrhea patients who had visited hospitals in Thailand. Sixty-six (22.6%) cases were positive according to the kit. All positive patients received mebendazole at 200 mg twice per day for 30 consecutive days or albendazole at 200 mg twice per day for 10 consecutive days. Later, stool concentration techniques, used to examine stool samples from all serologically positive individuals on three consecutive days, revealed C. philippinensis eggs, larvae, and/or adults. The kit is useful for screening and rapid diagnosis of intestinal capillariasis in chronic diarrhea patients in an endemic area for prevention of serious disease and facilitates treatment.

Development of an immunochromatographic point-of-care test for detection of IgG antibody in serodiagnosis of human trichinellosis

OBJECTIVE

Trichinellosis is a globally distributed food-borne parasitic disease. Initially, diagnosis is usually made based on clinical signs, symptoms, and history of eating raw or undercooked meat. In the present study, an immunochromatographic test (ICT) kit was developed to diagnose trichinellosis by detecting IgG antibodies in sera of infected humans.

METHODS

Somatic extract from Trichinella spiralis larvae was used as the antigen for the ICT kit development. Diagnostic efficacy was evaluated using human serum samples from proven trichinellosis patients, healthy persons, and those with other parasitic infections.

RESULTS

The diagnostic sensitivity, specificity, positive and negative predictive values and accuracy of the ICT kit were 100.0% (95%; CI 88.8 to 100.0%), 92.5% (95% CI; 86.9 to 96.2%), 73.8% (95% CI; 58.0 to 86.1%), 100.0% (95% CI; 97.3 to 100.0%) and 93.8% (95% CI; 89.2 to 96.9%), respectively.

CONCLUSIONS

This ICT diagnostic kit can be used as a testing tool for human trichinellosis. This test should permit rapid detection of infection to enable prompt anthelminthic treatment. It can also be used for retrospective diagnoses and field surveys based at laboratories where sophisticated equipment is lacking.

Helminth infections in fish in Vietnam: A systematic review

In Vietnam, fisheries play a key role in the national economy. Helminth infections in fish have a major impact on public health and sustainable fish production. A comprehensive summary of the recent knowledge on fish helminths is important to understand the distribution of parasites in the country, and to design effective control measures. Therefore, a systematic review was conducted, collecting available literature published between January 2004 and October 2020. A total of 108 eligible records were retrieved reporting 268 helminth species, among which are digeneans, monogeneans, cestodes, nematodes and acanthocephalans. Some helminths were identified with zoonotic potential, such as, the heterophyids, opisthorchiids, the nematodes Gnathostoma spinigerum, Anisakis sp. and Capillaria spp. and the cestode Hysterothylacium; and with highly pathogenic potential, such as, the monogeneans of Capsalidae, Diplectanidae and Gyrodactylidae, the nematodes Philometra and Camallanidae, the tapeworm Schyzocotyle acheilognathi, the acanthocephalans Neoechinorhynchus and Acanthocephalus. Overall, these studies only covered about nine percent of the more than 2400 fish species occurring in the waters of Vietnam. Considering the expansion of the aquaculture sector as a part of the national economic development strategy, it is important to expand the research to cover the helminth fauna of all fish species, to assess their potential zoonotic and fish health impacts.

Antigen Recognition Patterns of Intestinal Capillariasis Using Immunoblot-Based Serodiagnosis

BACKGROUND

Diagnosis of intestinal capillariasis depending on microscopic detection of parasitic stages is of low sensitivity, especially in cases with low worm burden. There is a necessity to develop sensitive and specific diagnostic tools of capillariasis for early treatment to avoid complications. Western blot (WB) technique showed promising results for antigen recognition patterns in several parasitic infections.

AIM OF THE STUDY

This study is directed to identify and evaluate relevant proteins of intestinal capillariasis crude worm antigens using WB immunodiagnosis.

MATERIALS AND METHODS

Capillaria crude worm antigens were extracted and analyzed using SDS-PAGE. Sixty serum samples belonging to 3 groups (20 individuals each) were included; Group I (shedding Capillaria in feces), Group II (infected with other parasites) and Group III (negative parasitological results). Reactivity of the resulting bands of Capillaria with serum samples was analyzed using WB technique.

RESULTS

Thirty-two immunoreactive bands were detected in WB analysis representing recognition of proteins with molecular weights (MW) varying from 19 to 110 kDa. Immunodominant proteins of 23.5, 31, 36.5, 40.5 and 44 kDa were recognized, respectively, in 35%, 30%, 85%, 95% and 75% of sera from patients with confirmed capillariasis and in 30%, 25%, 35%, 25%, and 20% of sera from those infected with other parasitic infections. One serum sample from group III gave reaction with 31 kDa band.

CONCLUSION

Immunodiagnosis of intestinal capillariasis using WB proved that 23.5, 31, 36.5, 40.5 and 44 kDa bands could be considered useful tools for diagnosis of capillariasis.

Comparison of the diagnostic performance of microscopic examination, Copro-ELISA, and Copro-PCR in the diagnosis of Capillaria philippinensis infections

Intestinal capillariasis is a parasitic zoonosis caused by the tiny nematode parasite Capillaria philippinensis. It is a major health problem that may lead to death if not diagnosed and treated appropriately. The difficulties in the diagnosis of C. philippinensis highlight the importance of developing accurate, sensitive, and specific methods for early diagnosis. This study aimed to detect the presence of C. philippinensis infection among 42 clinically suspected patients with certain criteria that are highly suggestive of capillariasis and to compare the diagnostic yield of microscopy, copro-ELISA, and PCR for the detection of copro-DNA. Sociodemographic characteristics and clinical data were also described for the infected group. Out of 42 patients, 10 were microscopically positive, 40 samples were positive by copro-ELISA, nested PCR detected 35 positive cases, with total detection rates of 23.8%, 95.2%, and 83.3% using direct microscopic examination, copro-ELISA, and PCR, respectively. The majority of positive cases were females, middle-aged people, and people from rural areas. The real number of cases infected with C. philippinensis may far exceed those estimated using microscopy. The diagnosis by copro-ELISA for the detection of C. philippinensis coproantigen and by nested PCR to identify parasite DNA revealed a higher number of positive cases. Using ELISA for the detection of coproantigen is a sensitive test that identifies the infection, yet it is not specific. Copro-DNA offers a satisfactory sensitive and specific method for the detection of infection in clinically suspected patients. The most susceptible individuals to C. philippinensis infection are females, middle-aged people, and people of low social standards. Intestinal capillariasis needs to be considered in patients who present with symptoms of chronic diarrhea and hypoalbuminemia because if these cases are left undiagnosed and untreated, they may suffer from lethal complications.

Asymptomatic Human Paragonimiasis among the Karen People in Tak Province, Thailand: A Case Report

During the mobile clinic activities in Tak Province, Thailand, Paragonimus sp. eggs were found in a fecal sample of a 72-year-old Karen resident. Paragonimus DNA was amplified from the stool sample and identified to P. heterotremus. The patient did not have any symptoms. Apparent pulmonary lesion was not found on the chest X-ray. The patient admitted habitual consumption of semi-cooked or roasted waterfall crabs for several years. The waterfall crabs collected from stream near the village were found negative for Paragonimus metacercariae. In northern Thailand, paragonimiasis remains as one of the public health concerns and should be ruled out for asymptomatic pulmonary patients.

Development of point-of-care testing tool using immunochromatography for rapid diagnosis of human paragonimiasis

Paragonimiasis, an important food-borne zoonosis, is caused by lung flukes of the genus Paragonimus. Several million people are actually infected or at risk. Paragonimiasis is a re-emerging disease in developing countries. Diagnosis of pulmonary paragonimiasis is made by finding eggs in sputa and/or fecal samples. Eggs are typically not found in ectopic paragonimiasis cases, so diagnosis depends on supportive information, such as a history of eating fresh water crabs or crayfishes, radiographic findings and immunological tests. Here, a new point-of-care-testing (POCT) tool is presented. It uses immunochromatography for serodiagnosis of human paragonimiasis using excretory-secretory antigen from Paragonimus heterotremus. It proved effective in diagnosing infections due to P. heterotremus, and was also successfully diagnosed with sera from infections with P. westermani and P. miyazakii. The diagnostic sensitivity, specificity, positive and negative predictive values and accuracy were 97.9%, 87.6%, 78%, 98.9%, and 90.8%, respectively. The developed POCT tool is rapid and simple to use not only for clinical diagnosis of paragonimiasis at the bedside or at well-equipped laboratories, but also at local and remote hospitals with limited facilities. Moreover, the POCT tool could be applied for epidemiological surveys of paragonimaisis in Asia where P. heterotremus, P. westermani and P. miyazakii are endemic.

Rapid diagnosis of parasitic diseases: current scenario and future needs

BACKGROUND

Parasitic diseases are one of the world's most devastating and prevalent infections, causing millions of morbidities and mortalities annually. In the past, many of these infections have been linked predominantly to tropical or subtropical areas. Nowadays, however, climatic and vector ecology changes, a significant increase in international travel, armed conflicts, and migration of humans and animals have influenced the transmission of some parasitic diseases from 'book pages' to reality in developed countries. It has also been noted that many patients who have never travelled to endemic areas suffer from blood-borne infections caused by protozoa. In the light of existing knowledge, this new trend can be explained by the fact that in the process of migration a large number of asymptomatic carriers become a part of the blood bank donor and transplant donor populations. Accurate and rapid diagnosis represents the crucial weapon in the fight against parasitic infections.

AIMS

To review old and new approaches for rapid diagnosis of parasitic infections.

SOURCES

Data for this review were obtained through searches of PubMed using combinations of the following terms: parasitological diagnostics, microscopy, lateral flow assays, immunochromatographic assays, multiplex-PCR, and transplantation.

CONTENT

In this review, we provide a brief account of the advantages and limitations of rapid methods for diagnosis of parasitic diseases and focus our attention on current and future research in this area. The approximate costs associated with the use of different techniques and their applicability in endemic and non-endemic areas are also discussed.

IMPLICATIONS

Microscopy remains the cornerstone of parasitological diagnostics, especially in the field and low-resource settings, and provides epidemiological assessment of parasite burden. However, increased use and availability of point-of-care tests and molecular assays in modern era allow more rapid and accurate diagnoses and increased sensitivity in the identification of parasitic infections.