Transfusion-transmitted malaria: donor prevalence of parasitaemia and a survey of healthcare workers knowledge and practices in a district hospital in Ghana

The global burden of malaria has been considerably reduced over recent years [1]. However malaria still remains a major cause of morbidity and mortality [2]. In 2015, the estimated number of malaria cases in Africa was 218 million out of which were 395,000 deaths [3]. The gains made in malaria may in part be attributed to the coherent way in which scientists and public health workers have cooperated together. This has been done by developing integrated control and elimination programmes tailored for specific endemic settings and an active engagement in the research and development agenda required for malaria eradication [4].

Since the first reported case of transfusion-transmitted malaria (TTM) in 1911 [5], transfusion has been recognized as a well known source for malaria transmission. In non-endemic countries, TTM has been well described and can cause serious illness in non-immune recipients so measures have been put in place to prevent its occurrence. Potential blood donors who have visited malaria endemic regions are not allowed to donate blood for a specific period depending on the policy of that country and this can range from 6 months to several years. However in malaria endemic countries, the burden of TTM and its contribution to the overall burden of malaria is unknown. The prevalence of Plasmodium parasitaemia in blood donors varies depending on the endemicity of malaria in the region they live. In Africa, prevalence was found to range between 0.7–55 % [6]. These blood donors are a potential risk for TTM. From the few published studies on the incidence of TTM in malaria endemic countries it is clear that not all recipients of malaria-positive blood develop TTM and, because of the high endemicity some may develop malaria post-transfusion unrelated to the transfusion [7, 8].

Screening healthy donors for malaria in endemic countries poses a diagnostic challenge. This is because currently there is no screening test that is practical, affordable and suitably sensitive for blood banks [9]. Microscopy, which is the gold standard and is most frequently used, is not a sufficiently sensitive test especially when parasite density is low. Microscopy is time consuming and cannot realistically be used on a large scale as a screening tool in blood banks. Malaria rapid diagnostic tests (RDTs) are increasingly being used in malaria endemic settings and are useful for complying with the WHO strategy of confirming diagnosis before treatment. RDTS are simple to use, and may now be superior or equal in diagnostic sensitivity for uncomplicated Plasmodium falciparum malaria [10]. They have not been widely evaluated as a screening tool in blood donors.

The knowledge of health workers about TTM has not been previously evaluated. There is very little published data relating to practices and attitudes of health workers to TTM. A study found that practices in a teaching hospital are related to particular departments where doctors worked [11].

The aim of this study was to determine the prevalence of malaria in blood donors by RDT, compared to controls. In addition the knowledge, attitudes and practices of health workers in the district hospital in relation to transfusion malaria was determined.

Donor and control groups were comparable in gender and age distribution. Males made up the majority in both groups; 55.0 % of donors and 57.0 % of controls respectively (Table 1). Those aged 15–25 years made up the majority and those above 46 years were the least in both groups (Table 1). The prevalence of P. falciparum was found to be 10 % in both donors and controls (Table 1). All those with positive malaria RDT malaria were aged 15–25 years. Males had a higher prevalence (10.9 %, 95 % CI 2.7–19.1 %) than females (8.9 %, 95 % CI 0.6–17.2 %) in donors. Similarly among controls, prevalence in males (14.0 %, 95 % CI 5.0–23.1 %) was higher than in females (4.7 %, 95 % CI 2.7–19.1 %) although the differences between males and females were not significant.

TTM in malaria endemic countries is attracting increasing attention with the current drive to reduce all avenues of transmission. TTM had been a neglected area of transfusion but since a meeting in Mombasa, Kenya identified TTM as a key gap in transfusion research in 2008 [14], there have been at least three major review articles and several other publications on different aspects of TTM.

This study showed that the prevalence of P. falciparum malaria in donors by RDT method was 10 %. This was similar to the findings from a study carried out in Kumasi, Ghana where P. falciparum prevalence was 13.7 % in donors by RDT [8]. Other African studies have found malaria prevalence in blood donors to be as high as 50 % [6]. The presence of parasitaemia in blood donors represents a potential risk to transfusion recipients and can result in TTM occurring in up to 28 % of recipients [7]. Certain factors such as refrigeration of blood at 4 °C and the immunity of the recipient may affect the susceptibility of individual recipients. Currently most blood banks in malaria-endemic African countries are not routinely screening blood for malaria. Ethical questions have been raised concerning whether it is appropriate to reject parasitaemic blood donors in malaria endemic countries where blood supplies are inadequate and the risks of clinically important TTM have not been well documented. Rejecting such donors will exacerbate already critical blood shortages and have the potential to increase mortality. Malaria RDTs may have a high rate of false positives test because of the presence of circulating antigens even after treatment. In recent times however, the role of malaria RDT testing cannot be disputed. RDT use has expanded greatly due to the WHO treatment guidelines which recommend the confirmation of parasitaemia prior to treatment with ACT [15]. The sensitivity of the RDTs has also been greatly improved and together with microscopy, they represent the best hope for accurate diagnosis as a key component of successful malaria control [16]. This study found the prevalence of P. falciparum malaria in donors and their controls to be the same (10 %). This is not surprising and is an indication that the blood donors are a true representation of the healthy adult population in the district. In many African countries the donor population is usually male dominated. However in this study, females were almost half of all donors. In this study, it is unclear why the prevalence of parasitaemia in males was more than double that of females in the control group. Some studies have established that parasitaemia is not significantly associated with the gender of donors. Ukaga et al. [17] found prevalence rates of 22.5 and 25.4 % for males and females respectively in Owerri, Nigeria.

The survey results showed that only 9 % of the respondents had attended any workshop on blood transfusion in the past 12 months. In Ghana, professional bodies require continuous professional development while health institutions encourage service training in all aspect of medicine. In many high-income countries, regular training on blood transfusion is mandatory, reflecting the importance of transfusion for patient safety and treatment. Much more advocacy is needed by the health professions and blood services in Ghana to ensure that transfusion is included in undergraduate curricula and in-service training programmes.

Knowledge about TTM was generally low among health workers in Akatsi. Almost half of the health workers had not heard about TTM. Malaria has been neglected a transfusion-transmitted infection, having been substantially overshadowed predominantly by a focus on HIV. Almost all respondents wrongly assumed that screening for malaria was being performed in Ghana. It is likely that the workers assumed that because routine screening takes place for HIV and hepatitis, malaria screening also takes place. It is unclear why a quarter of respondents admitted they were not sure if screening was done in their hospital but did not say so when questioned about screening across Ghana. If this level of misinformation occurs across Ghana then there is a clear need to provide education on TTM and particularly around strategies that can be used to reduce transmission through transfusion and to correct some assumptions that may negatively affect practice. It is interesting to observe that many health workers were unwilling to transfuse hepatitis B or syphilis positive blood but many were willing to transfuse malaria positive blood. Further investigations to determine the rationale for this will be useful.

Nearly all respondents (89.1 %) knew the most effective way of preventing TTM. This high level of knowledge could be possibly due to the effective malaria campaigns going on across the country. However, a third of health workers did not think that routine use of anti-malarials in transfusion will ultimately contribute to the spread of drug resistance. Current World Health Organization policies and treatment guidelines recommend that parasitological confirmation of malaria should be done before initiating the treatment [18]. However this advice is difficult to interpret in the context of blood transfusion and contradicts other guidelines [19] which advise that all transfusion recipients should receive anti-malarials. It is not surprising that this confusing guidance translates into lack of consistency in the prevention of TTM in clinical practice [11].

TTM is a ‘hidden’, neglected and under researched reservoir of ongoing malaria transmission. The recent announcement of a new one billion dollar fund to eliminate malaria means that renewed efforts are needed to understand and reduce the risks of malaria [20] transmission through blood transfusion.