Reply To: TMID608-6 Development of malaria diagnosis

[HTOO WAI AUNG]

If the resources are available, I will use the molecular techniques for malaria detection in mosquitoes as the first priority. Although midgut dissection for finding oocyst and sporozoites is recognized as gold standard, it requires skilled personnel, time consuming and cannot specify the species yet. In concerning with immunoassay such as Slot blot immunoassay: ECL SB and CSP ELISA, although CSP ElISA has many advantages such as robustness and cheapness, and recognized as most widely used methods, there are several reports that CSP ELISA overestimates the true salivary gland infection rate. Furthermore, it is relatively insensitive to low-level infection.
Molecular techniques such as nested PCR,PCR-RFLP, MALDI-TOF MS, and COX-I PCR have higher sensitivity than the other techniques (can detect in less than 10 sporozoites per µL), less time consuming, require least expert among the available techniques, and can determine the specific species. As the drawbacks, it has the limited Plasmodium life-stage specificity in comparing with mosquito dissection and CP ELISA methods. Among the PCR methods, COX-I PCR is is more sensitive, less expensive, and faster than other PCR methods.
In brief, it will be best if the conjunction use of these three methods depending on the situation. As an example, PCR method and CSP ELISA can use in combination for the detection of low-density infections within a mosquito and confirmation of positive infectious mosquitoes.