The Risk of Re-Emergence of Plasmodium malariae in South-East of Iran as Detected by Nested Polymerase Chain Reaction

For the exact detection of parasite species, nested polymerase chain reaction based on small subunit ribosomal RNA gene was conducted, using 140 blood samples from symptomatic malaria cases. Microscopic examination of blood smears detected P. vivax, P. falciparum and a number of mixed infections with these two species and no detection of P. malariae. With the molecular based identification technique, in addition to diagnosis of a higher number of mixed infections, two cases of P. malariae was also identified after 22 years. These results point to the need of the development or utilization of a more accurate diagnostic method to distinguish between P. vivax and P. malariae. It is concluded that P. malariae seems to be re-emerged in South-East of Iran and its co-existence with the other two plasmodium species, P. vivax and P. falciparum, needs consideration during human malaria diagnosis to avoid ignorance and misdiagnosis of this parasite species. This is particularly important in view of the fact that the choice of drug for the anti-malarial therapy depends on the parasite species.