Evaluation of Lateral Flow Test for Detection of Cryptosporidium Species in Human Fecal Specimens

Abstract

Cryptosporidium is common cause of waterborne diarrheal disease worldwide, both in developing and developed countries as well as urban and rural areas; due to poor sanitation and urban crowding, Cryptosporidium infections are more prevalent in underdeveloped areas. There is need for a practical point-of-care diagnostic test that is rapid, reliable and feasible for use in the field. Since Cryptosporidium species causing invasive intestinal disease and infection, it is important to detect Cryptosporidium in diarrheal fecal efficiently and instantly. In clinical sites it is necessary to detect Cryptosporidium pathogen using a reliable rapid point of care test over other conventional diagnostic tools like microscopy. A new rapid lateral flow fecal antigen detection test for Cryptosporidium was evaluated using diarrheal stool samples from a cohort of children in Bangladesh. In this study, The Cryptosporidium EZ VUE test (developed and manufactured by TechLab®, Blacksburg, VA) was analyzed to establish it as an alternative method to detect Cryptosporidium-specific oocyst antigens in fecal specimens in clinical areas within 10 minutes and with less skilled personnel. In this study, fecal samples were collected from Mirpur slum area of Dhaka city. A total of 100 diarrheal samples were collected from100 children whose age ranges from 0-24 months. The diagnostic performance of recently released rapid test was compared with Cryptosporidium ІІ Enzyme Linked Immuno-sorbent Assay (ELISA) from TechLab® Cryptosporidium QUIK CHEK™ , real time PCR, and Cryptosporidium QUIK CHEK™. The Cryptosporidium EZ VUE test was exhibited 100% sensitivity and 93.94% specificity and the 89.47% positive predictive value and 100% negative predictive value with compared to the Cryptosporidium ІІ ELISA; were found to be 70% sensitivity and 94% specificity, and 92.1% positive predictive value and 75.81% negative predictive value as compared with RT-PCR; and were found to be 100% sensitivity and 98.41% specificity, accordingly, 97.37% positive predictive value and 100% negative predictive value as compared with Cryptosporidium QUIK CHEK™. Furthermore, Cryptosporidium EZ VUE test was evaluated with E. histolytica positive samples and Giardia positive samples by cross check reactions. All positive samples were exposed as negative by Cryptosporidium EZ VUE test. That means Lateral Flow method had no cross reaction with both E. histolytica and Giardia positive samples. These results indicate that EZ VUE assay can be successfully used for specific and rapid detection of Cryptosporidium oocysts in clinical fecal samples and can also be implemented as an alternative method of conventional microscopy in both research center and in clinical sites.