Detection of mixed Plasmodium falciparum & P. vivax infections by nested-PCR in Pakistan, Iran & Afghanistan

Abstract

Background & objectives: Species identification and information on transmission pattern of malaria parasite in any malaria endemic area is key to success for a malaria control programme. In this investigation, malaria diagnosis using molecular method was used to assess the transmission pattern of malaria parasite in three malaria endemic regions: Afghanistan, Iran and Pakistan.

Methods: Blood samples were collected from the patients presenting with vivax malaria from Afghanistan (n=108), Iran (n=200) and Pakistan (n=199). Malaria parasite detection was made by the gold standard (microscopy) and also nested-PCR assay, using 18S small sub-unit ribosomal RNA (ssrRNA) gene.

Results: Based on microscopy method, the level of mixed infection was zero to 2.5 per cent; however, nested-PCR assay detected 6.5, 22 and 23.5 per cent mixed infections in samples collected from Afghanistan, Iran and Pakistan, respectively. The present results showed that the co-infection of P. vivax with P. falciparum was frequent in malaria endemic regions of Iran and Pakistan.

Interpretation & conclusion: The present data suggest the need for improving microscopy diagnosis method and the clinician should also have careful clinical observation, along with the reports on Giemsa- stained thick blood films, particularly in summer time when P. vivax is predominant. Also sharing information on transmission pattern of mixed infection among these countries may help in designing better control strategies for malaria.