Identifi cation of Plasmodium species from outdated blood samples by nested-PCR compared with microscopy diagnosis in Jazan region, Saudi Arabia

Precise diagnosis of plasmodium species is essential for accurate and prompt malaria control and elimination.The present study was conducted to assess the effi ciency of malaria parasites' diagnosis by microscopy and nested-PCR techniques in Jazan region.Eight hundred eighty four samples were collected from hospitals and malaria control centers of the eleven Governates of Jazan region to confi rm their microscopy diagnosis for Plasmodium species.One hundred thirty eight (15.6%)samples were randomly selected from the saved positive microscopy confi rmed samples.The samples were re-diagnosed by microscopy for plasmodium species and found positive for two plasmodium species (128 for P. falciparum [92.8%] and 10 for P. vivax [7.2%]).But no other plasmodium species or mixed-infections were detected.On other hand, the diagnosis by nested-PCR indicated 119 (86.23%) and 6 (4.35%) mono infection by P. falciparum and P. vivax, respectively.In addition, the method detected also 13 (9.42%)mixed-infections with both P. falciparum and P. vivax.Considerable numbers of species mismatch and under-reporting of mixed infections had been noticed in the diagnosis of malaria by microscopy alone in Jazan region.The nested-PCR is valuable technique as a confi rmatory test and should be considered by reference laboratories in the region and other malaria endemic regions of the Kingdom of Saudi Arabia.