A rapid test for detecting taeniasis cases will provide a key tool needed for cysticercosis control programs. The MICT developed here represents the first report of a rapid test for taeniasis and establishes proof of principle that a rapid MICT using recombinant proteins for serodetection of taeniasis and cysticercosis is possible. The ES33-MICT performed with characteristics similar to those of the ES33 EITB (14
) but required less time to perform (45 min versus 3.5 h) and little technical expertise. This would make the MICT suitable as a point-of-care test.
The ES33- and T24-MICTs, as developed, are quantitative and reproducible. Generating quantitative results allows the use of a cutoff value, thus improving sensitivity compared to that of visual reading. The best performance of the ES33-MICT was achieved with a cutoff point of the MAR ratio value at 1.1, which resulted in a sensitivity of 94.5% and a specificity of 96%. However, even better sensitivity is desirable for taeniasis screening. When the cutoff point was adjusted in this evaluation to increase sensitivity (to ~97%), the specificity decreased (to 94%), as expected. However, this concomitant decrease in specificity may not be a problem, since treatment of taeniasis is both safe and inexpensive. Unfortunately, the sensitivity of the ES33-MICT could not be improved further without a drastic decrease in specificity.
One clear advantage of this method is the use of magnetic particles as the detection system in conjunction with the MAR system. The magnetic particle conjugate does not bleach across the time, as is the case with other reporters, such as gold and fluorescence (12
), and the assay performances conducted seven days later were similar to those calculated from the data generated at the time of testing (Table ).
Two disadvantages of the current version of ES33- or T24-MICTs were recognized. First is the requirement for a liquid conjugate. Drying the conjugate onto the pad will improve the usefulness of the test because it will reduce the number of steps needed to carry out the assay and possibly eliminate the need to maintain a cold chain. This is only a matter of process development and can be achieved by industrial manufacturers in proper manufacturing environments. Second, optimal sensitivity and specificity are dependent on the benchtop magnetic assay reader. This hinders the portability of the tests. Although it was possible to identify taeniasis cases based on visual observation, the sensitivity of the test decreased (Table ). A possible solution is use of a hand-held reader—a prototype, which is already constructed by the proprietary company MagnaBioSciences but is not commercially available yet. If quantification is needed, as was the case in this study, after reading visually in the field, the devices can be brought back to a centralized station, where a benchtop reader is available. As demonstrated in this study, the time interval from testing to reading should not exceed 7 days.
We also developed a MICT to detect human cysticercosis antibodies; the performance of the T24-MICT was comparable to the performance of other methods using rT24H. Like other serological methods for detection of neurocysticercosis, such as the LLGP-EITB (the current standard assay of reference) (24
), a cysticercosis antigen specific EITB (9
), and ELISAs (3
), the T24-MICT has reduced sensitivity for detection of cases with a single viable cyst. Although this T24-MICT assay was evaluated using human sera, in principle, the test could be used for screening pig sera, as this method is species independent. Rapid assessment of human cysticercosis may not be needed in control programs, but pen-side testing for porcine cysticercosis may be useful to monitor control (6
In conclusion, we have shown that rapid test methods using recombinant proteins are feasible for immunodetection of taeniasis and human cysticercosis. Extensions of this work should focus on improved sensitivity for taeniasis detection that will allow determination of all true-positive cases in the field. Additionally, adaptation of this method for the immunodetection of porcine cysticercosis is needed.