Malaria is the major cause of morbidity and mortality in adults and children worldwide. According to the World Health Organization (WHO), there were an estimated 198 million cases of malaria in 2013, of which approximately 82 % were in the African Region, followed by South-East Asia (12 %), and eastern Mediterranean regions (5 %). About 8 % of the globally estimated cases are due to Plasmodium vivax and this ratio increases to 47 % outside the African continent [1].
Accurate diagnosis is an important tool in the fight against malaria and universal access to a parasitological test is part of the WHO objectives [1]. Microscopy depending on Giemsa-stained blood smears has been considered as the reference gold standard [2–6] for the diagnosis of malaria for more than a century. On the other hand, microscopy techniques fail to detect mixed infections, when one of the Plasmodium species is present at low levels (100 parasites/mL), or modified by anti-malarial drug treatment [6, 7] and it is also a labour-intensive procedure and requires well-trained personnel [4]. However, molecular techniques have been capable for the detection and identification of malaria parasites with low and mixed parasitaemia [8]. According to the WHO, PCR was determined as more sensitive and specific than all other techniques. It does, however, require specialized and costly equipment and reagents, as well as laboratory conditions that are often not available in the field [5, 9].
The Southeastern Anatolia Region (GAP) is the most malaria-endemic region, where one of the two largest malaria epidemics of Turkey was occurred in 1994 with 84,345 cases [10]. According to Health Ministry data, it was estimated that 89 % of 36,842 malaria cases were detected in the GAP of Turkey [11].
In the GAP of Turkey, malaria transmission is seasonal, generally occurring between March and October, and shows a marked local distribution [12]. Plasmodium vivax is the only agent of indigenous malaria cases and only imported Plasmodium falciparum cases are seen in Turkey [13–16]. The GAP is one of the relatively less developed regions of the country, comprising nine administrative provinces (Adiyaman, Batman, Diyarbak?r, Gaziantep, Kilis, Mardin, Siirt, Sanliurfa, and Sirnak) in the basins of the Euphrates and Tigris, and in Upper Mesopotamia. In this region, improper or excessive use of irrigation channels and deficiency in irrigation water management lead to puddles and standing water near fields. These puddles, standing water, and swamps contribute to the development of parasite larvae and breeding of Anopheles mosquitoes. As reported by the WHO, Anopheles mosquitoes breed in water and each species has its own breeding preference; for example, some prefer shallow collections of fresh water, such as puddles, rice fields, and hoof prints [17]. The GAP has been converted into an appropriate environment including temperature and climate changes for mosquito breeding and the development of parasites. Farm workers living close to puddles, standing water, and swamps have become a risk group for malaria. Many seasonal farmworkers come to Sanliurfa from different parts of Turkey to work in agriculture and many of them move from their home towns to other provinces of Turkey. The seasonal workers raised serious concerns that malaria acquired in Sanliurfa would be disseminated to other regions of Turkey. Sanliurfa is located on the board with Syria where a large influx of displaced persons from neighbouring countries.
These environmental conditions and migration from neighbouring countries result in Sanliurfa being a malaria-endemic province. Generally, the diagnosis of malaria depends on microscopical examination of thick and thin Giemsa-stained blood smears in this study area. There were no data about the diagnosis of malaria using nested PCR (nPCR) in Sanliurfa. This was the first study to compare nPCR and microscopy in Sanliurfa, in Turkey.
In light of these data, the aim of this study was to detect Plasmodium and a subspecies of Plasmodium using filter paper and compare the results of nested PCR (nPCR) with microscopy for accurate malaria diagnosis and present the epidemiological data in Sanliurfa, southeastern Turkey.