Plasmodium ovale curtisi and Plasmodium ovale wallikeri in North-West Ethiopia

Abstract

BackgroundIn Ethiopia Plasmodium falciparum and Plasmodium vivax are the dominant species accounting for roughly 60 and 40% of malaria cases, respectively. Recently a major shift from P. falciparum to P. vivax has been observed in various parts of the country but the epidemiology of the other human malaria species, Plasmodium ovale spp. and Plasmodium malariae remains poorly understood. The aim of this study was to assess P. ovale curtisi and wallikeri infection in north-west Ethiopia by using microscopy and nested PCR.MethodsA health institution-based survey using non-probability sampling techniques was conducted at Maksegnet, Enfranze and Kola Diba health centres and Metema hospital in North Gondar. Three-hundred patients with signs and symptoms consistent with malaria were included in this study and capillary blood was collected for microscopic examination and molecular analysis of Plasmodium species. Samples were collected on Whatman 903 filter papers, stored in small plastic bags with desiccant and transported to Vienna (Austria) for molecular analysis. Data from study participants were entered and analysed by SPSS 20 software.ResultsOut of 300 study participants (167 males and 133 females), 184 samples were classified positive for malaria (133 P. falciparum and 51 P. vivax) by microscopy. By species-specific PCR 233 Plasmodium spp (95% CI: 72.6-82) were detected and the majority 155 (66.5%, 95% CI: 60.2-72.3) were P. falciparum followed by P. vivax 69 (29.6%, 95% CI; 24.1-35.8) and 9 (3.9%, 95% CI: 2-7.2) samples were positive for P. ovale. Seven of P. ovale parasites were confirmed as P. ovale wallikeri and two were confirmed as P. ovale curtisi. None of the samples tested positive for P. malariae. During microscopic examination there were high (16.3%) false negative reports and all mixed infections and P. ovale cases were missed or misclassified.ConclusionThis study indicates that P. ovale malaria is under-reported in Ethiopia and provides the first known evidence of the sympatric distribution of indigenous P. ovale wallikeri and P. ovale curtisi in Ethiopia. Therefore, further studies assessing the prevalence of the rare species P. ovale and P. malariae are urgently needed to better understand the species distribution and to adapt malaria control strategies.

Performance of loop-mediated isothermal amplification (LAMP) for the diagnosis of malaria among malaria suspected pregnant women in Northwest Ethiopia

“…Malaria is the most prevalent seasonal disease in the area, and is the second most common reportable disease at the health centre. Both seasonal Plasmodium vivax and year-long P. falciparum exist in the area [21, 22]. Peak malaria transmission occurs from October to December.…”

Evidence of non-Plasmodium falciparum malaria infection in Kédougou, Sénégal

“…However, with intensified efforts to control the incidence of these primary species, there is rising concern over the prevalence of additional malaria species including Plasmodium ovale spp. and Plasmodium malariae into the niches previously occupied by P. falciparum and P. vivax [1–3]. Should these other species be undetected by current diagnostic methods, there is the potential that they may make substantive and possibly increasing contributions to overall malaria burden.…”

“…For example, there are increasing reports of P. ovale spp. in various countries across the African continent, including Ethiopia, Uganda, Equatorial Guinea, and Kenya [1–3]. Historically, and recently, there have been ad hoc reports of malaria infections caused by species other than P. falciparum in Sénégal.…”

Diagnostic performance of rapid diagnostic tests for the diagnosis of malaria at public health facilities in north‐west Ethiopia

“…Close to one-third of malaria cases in Ethiopia are caused by P. vivax. P. ovale and P. malariae have only recently been identified as contributing a significant proportion of malaria cases [1,2].…”