Molecular diagnostic of cytomegalovirus, Epstein Barr virus and Herpes virus 6 infections among blood donors by multiplex real-time PCR in Ouagadougou, Burkina Faso

Introduction In most developing countries, Cytomegalovirus (CMV), Epstein Barr virus (EBV) and Herpes virus 6 (HHV-6) are not diagnosed in blood donors. The aim of this study is to determine the prevalence of these viruses in blood donors from the city of Ouagadougou, Burkina Faso. Methods The study included 198 blood donors of the Regional Blood Transfusion Centre of Ouagadougou. Multiplex real time PCR was used to diagnose the three viruses. Statistical analysis was performed with the software EpiInfo version 6 and SPSS version 17. P values ≤ 0.05 were considered significant. Results Of 198 samples tested, 18 (9.1%) were positive to at least one of the three viruses. In fact, 10 (5.1%) were positive for EBV, 10 (5.1%) positive for CMV and 12 (6.1%) positive for HHV-6. Viral infections were higher in women than in men, EBV (8,6% versus 4.3%), CMV (8.6% versus 3.7%) and HHV-6 (11.4% versus 4.9%). EBV / CMV / HHV-6 co-infection was found in 3.5% (7/198) of blood donors. Conclusion The prevalence recorded in this study is low compared to those found in previous studies from the sub-region among blood donors. The molecular diagnostic test used in our study could explain the differences with previous studies.


Introduction
In Burkina Faso, as in most developing countries, Cytomegalovirus (CMV), Epstein Barr virus (EBV) and Herpes virus 6 (HHV-6) are not diagnosed in blood donors [1]. CMV, EBV and HHV-6 infections are transmitted through blood and remain a significant cause of mortality and morbidity, especially in immunocompromised persons [2,3]. Gastrointestinal CMV infections are extremely common in immunosuppressed patients [4]. CMV infection has been considered an important resistance factor to therapy in patients with intestinal inflammation, taking antiviral therapy [5,6]. CMV infection of the intestine is clinically significant but not always with the classic cytopathic viral changes [7]. Congenital CMV infection is cited as the most important cause of infectious diseases of the central nervous system and hearing loss in children. It also endangers human fetus development; this issue makes the development of new strategies to prevent the acquisition and transmission of CMV a priority [8,9].
EBV is one of the most common human viruses and is found throughout the world. It has been reported that 90% of adults are asymptomatic carriers. In immunocompromised individuals, the virus is activated and becomes an oncogene. EBV early infection has been described in children in Africa but also in developed countries where the primary infection is delayed until adulthood [10][11][12].
HHV6 is a virus similar to CMV; its discovery dates back to1986. It spread on the pandemic mode as CMV and EBV. An estimated of 80 to 90% is the number of people carrying the HHV-6 intermittently in their saliva [13,14]. These three viruses are responsible for asymptomatic infections in immunocompetent individuals. In fact they cause disease especially in patients whose immune systems have been weakened, such as those treated with immunosuppressors, those affected by the human immunodeficiency virus (HIV) [15] and pregnant women. These viruses are responsible for many cancers, including Burkit's lymphoma (BL) observed endemic among African children [16], the nasopharynx lymphoma [17], B and T cells lymphomas [11,18].
These types of cancers called non-Hodgkin represent the third type of cancer in sub-Saharan Africa, after breast and cervical cancers [19]. The objective of this study was to determine the prevalence of these three viruses in blood donors of the Regional Blood

Results
Our study population consisted of 198 blood donors of which 17.7% were women and 82.3% were men. The donors' age ranged between 18 and 56 years with an average of 24.24 ± 6.69 years.
More than three quarters (78.3%) of blood donors were from urban areas. The three herpes viruses: EBV, CMV and HHV-6 were diagnosed among blood donors in this study. Of the 198 blood donors tested 18 (9.1%) were positive for at least one of the three viruses. The prevalence of EBV, HHV-6 and CMV was respectively 5.1%; 6.1% and 5.1% (Table 1). No co-infection between EBV / CMV, EBV / CMV and HHV-6 / HHV-6 was observed in this study.
While the triple infection EBV / CMV / HHV-6 concerned 3.5%  higher, respectively in women compared to men, but the observed difference was not statistically significant (Table 2). We did not observe significant differences by comparing the prevalence of human herpes virus between urban and rural areas. However, the prevalence of EBV and CMV was slightly higher in urban than rural areas respectively (5.8% vs 2.3% and 5.2% vs 4.7%); while that of HHV-6 was slightly higher in rural than in urban areas (7.0% vs 5.8%) ( Table 2).

Discussion
We show in this study that the overall prevalence of human herpes virus in blood donors was 9.1%. The prevalence of EBV, HHV-6 and CMV was respectively 5.1%; 6.1% and 5.1%. The prevalence of infections, CMV and HHV-6 are more common in young individuals [21,25,26]. In our study, we obtained the prevalences of 5.1%; 6.1% and 5.1% respectively for EBV, HHV-6 and CMV, and the EBV infection triple / CMV / HHV-6 concerned 3.5% (7/198)   Herpes Viral infections were higher in women than in men;  Molecular epidemiology is lower compared to the seroprevalence described in previous studies.

Competing interests
The authors declare no conflicts of interest  Table 1: Prevalence of EBV, CMV and HHV-6 in blood donors Table 2: Infection with CMV, EBV and HHV-6 as a function of the age, sex and place of blood donation