Lateral Flow Assay For Diagnosis Research Articles

SEROEPIDEMIOLOGY AND RISK FACTORS OF HUMAN TOXOPLASMOSIS IN ERBIL, KURDISTAN REGION, IRAQ

Introduction: This study aimed at the detection of anti-Toxoplasma. gondii antibodies in human blood samples using immunological tests and to investigate the potential risk factors. Methods: Five hundred and twenty samples were collected from individuals aged between 10 to 71 years old. All samples were tested by latex, lateral flow assay, and Enzyme-linked immunosorbent assay (ELISA). Personal data which may be potential risk factors were collected. Results: Out of the 520 Blood samples tested, 23.3%, 25.4%, 20.2%, and 9.8% had positive results for latex, lateral flow assay, ELISA IgG, and ELISA IgM, respectively. The prevalence of T. gondii antibody was high in the elderly age group that had a seropositive result of 26.1%,27.5%, and 23.2% for latex, lateral flow assay, and ELISA IgG, respectively. Conclusion:The two major risk factors associated with the infection are contact with raw meats and consumption of raw vegetables.Latex and lateral flow assay for diagnosis of T. gondii in routine screening might be a cost-effective testing strategy. Consumers are recommended to heat the food of animal origin, and wash all vegetables and fruit carefully before consumption.

Combining isothermal recombinase polymerase amplification with lateral flow assay for diagnosis of P. cynomolgi malaria infection.

Plasmodium cynomolgi is a nonhuman primate parasite that causes malaria in humans and is transmitted by the Anopheles mosquito. Macaques, the natural hosts of P. cynomolgi, are widely distributed in Asia, especially in Southeast Asia. Anthropogenic land-use changes and wildlife habitat reduction due to local environmental changes, deforestation, urban expansion, and construction increased the frequency of human-macaque-vector interactions and facilitated the emergence of zoonotic malaria, causing an exponential increase in the infection rates in this area. Although microscopic tools are the gold standard for malaria diagnosis, they have very low sensitivity. Therefore, disease control and prevention require rapid, sensitive and accurate diagnostic tests. This study aims to develop a diagnostic method using a recombinase polymerase amplification (RPA) combined with a lateral flow (LF) strip method to specifically diagnose P. cynomolgi. Laboratory validation determined the method's sensitivity and specificity compared to the nested PCR method. The lower limit of detection was 22.14 copies/μl of recombinant plasmid per reaction. The combination method represented 81.82% sensitivity and 94.74% specificity compared to the nested PCR. The diagnostic testing developed in this study combines a recombinase polymerase amplification (RPA) and a lateral flow (LF) strip, offering rapid high sensitivity and specificity. Further development of this technique could make it a promising method for detecting P. cynomolgi.

Comparative evaluation of blood based lateral flow assay for diagnosis of brucellosis in livestock species

Brucellosis is a zoonotic and economically important disease of livestock. Pen side diagnostics are the need of the hour for the rapid diagnosis of brucellosis. The present study aimed to evaluate blood based lateral flow assay (LFA) with serum based LFA and rose bengal plate test (RBPT) for diagnosis of brucellosis. Sera/blood samples [792: cattle, 153; buffalo, 55; sheep, 140; goats, 219; and pigs, 225] were collected from Karnataka, India with history of repeat breeding, retention of placenta and abortion.The seropositivity of brucellosis in cattle, buffalo, sheep, goats and pigs was 7.84, 3.63, 12.85, 2.73 and 39.11% by RBPT; 5.88, 3.63, 8.57, 2.73 and 31.1% by blood-LFA; and 7.18, 3.63, 10.71, 3.19 and 32.88% by serum-LFA. Relative specificity of blood based LFA was between 98.97 to 99.53% and 97.42 to 100% in comparison to serum-LFA and RBPT, respectively in all the species. The relative sensitivity for all the species ranged from 64.29 to 83.33% by blood-LFA and 57.14 to 84.09% by serum-LFA. The diagnostic accuracy of blood-LFA to RBPT and serum- LFA ranged from 91 to 99% among the species studied. It is opined that blood based LFA can serve as diagnostic test in place of serum based LFA for brucellosis screening in multiple livestock species and suggested for adaptation on-farm, slaughter, market, clinical and prepurchase surveillance of brucellosis in the country.

A robust dry reagent lateral flow assay for diagnosis of active schistosomiasis by detection of Schistosoma circulating anodic antigen

An earlier reported laboratory assay, performed in The Netherlands, to diagnose Schistosoma infections by detection of the parasite antigen CAA in serum was converted to a more user-friendly format with dry reagents. The improved assay requires less equipment and allows storage and worldwide shipping at ambient temperature. Evaluation of the new assay format was carried out by local staff at Ampath Laboratories, South Africa. The lateral flow (LF) based assay utilized fluorescent ultrasensitive up-converting phosphor (UCP) reporter particles, to be read by a portable reader (UPlink) that was also provided to the laboratory. Over a period of 18months, about 2000 clinical samples were analyzed prospectively in parallel with a routinely carried out CAA–ELISA. LF test results and ELISA data correlated very well at CAA concentrations above 300pg/mL serum. At lower concentrations the UCP–LF test indicates a better performance than the ELISA. The UCP–LF strips can be stored as a permanent record as the UCP label does not fade. At the end of the 18months testing period, LF strips were shipped back to The Netherlands where scan results obtained in South Africa were validated with different UCP scanning equipment including a novel, custom developed, small lightweight UCP strip reader (UCP-Quant), well suited for testing in low resource settings. ConclusionThe dry format UCP–LF assay was shown to provide a robust and easy to use format for rapid testing of CAA antigen in serum. It performed at least as good as the ELISA with respect to sensitivity and specificity, and was found to be superior with respect to speed and simplicity of use. Worldwide shipping at ambient temperature of the assay reagents, and the availability of small scanners to analyze the CAA UCP–LF strip, are two major steps towards point-of-care (POC) applications in remote and resource poor environments to accurately identify low (30pg CAA/mL serum; equivalent to about 10 worm pairs) to heavy Schistosoma infections.