Acute human cytomegalovirus infection among voluntary blood donors in the Lake Victoria zone blood transfusion centre: should it be considered in screening?

BACKGROUND: Despite blood transfusion being a lifesaving option, it may be associated with blood borne infections including human cytomegalovirus(HCMV). The World Health Organization recommends screening of blood products for HCMV before transfusion to pregnant women, neonates and immunocompromised patients. However, this is not routinely practised in many resource limited countries.
OBJECTIVE: This study aimed at determining seroprevalence of specific HCMV IgM antibodies among volunteered blood donors at the Lake Victoria zone blood transfusion centre.
METHODS: A total of 228 sera from volunteered blood donors were analyzed using HCMV IgM µ capture enzyme linked immunosorbent assay as per manufacturer's instructions. Data were analyzed by STATA version 13.
RESULTS: The median age of the study participants was 19 interquartile range (IQR): 18-23 years. The seroprevalence of specific HCMV IgM antibodies was found to be 23/228 (10.1%, 95% confidence interval (CI): 6-14. None of the factors was found to be associated with HCMV IgM seropositivity among blood donors.
CONCLUSION: One out 10 blood donors in the Lake Victoria zone blood transfusion centre is acutely infected with HCMV. There is a need to consider screening of HCMV before blood transfusion particularly in resource limited countries where HCMV is endemic.

Introduction

Blood transfusion is a medical intervention with an essential role in patient management particularly in emergency cases. Although it is lifesaving, it may be a potential risk for transmitting blood borne infections1. The World Health Organization (WHO) recommends that blood for transfusion should be screened for blood-borne infections such as Hepatitis C Virus, Hepatitis B Virus (HBV), Treponema pallidum, and Human Immunodeficiency Virus (HIV) on routine basis2. In addition, the WHO also recommends that blood to be transfused to neonates, pregnant women and immunocompromised patients should be screened for Human cytomegalovirus (HCMV)3. However, in most of resource limited countries HCMV is not considered in any of these cases. HCMV infection in infants is associated with meningitis, pneumonia and sepsis while infection in pregnant women may lead to congenital infections that may cause life threatening congenital anomalies. Furthermore, HCMV infection in immunocompromised individuals is associated with severe life threatening diseases such as meningitis and sepsis4–76,8–11. It should be noted that, in immunocompetent individuals, acute primary HCMV infection is often self limited followed by latency mostly in CD34+ haemopoietic progenitor cell in bone marrow and CD13+, CD14+ peripheral blood mononuclear cells with potential of reactivation during immunocompromised state12.

Tanzania, like many other resource limited countries, the blood donors are not routinely screened for HCMV. Nonetheless, the donated blood has been also used for the management of pregnancy related anemia, immunocompromised patients as well as neonates in need. This poses a potential risk for transfused individuals which might be associated with life threatening clinical manifestations13,14. Despite HCMV being reported in a significant proportion of blood donors in many of the endemic countries15–17, there is no routine HCMV screening with limited data among blood donors in Tanzania. This has prompted us to investigate the seroprevalence of acute/recent HCMV infection among blood donors to provide appropriate recommendations for policy makers to consider it in screening particularly in case blood units are needed by vulnerable groups.

Methods

Study design, study area, sample size and ethical considerations

A cross-sectional study using 228 achieved sera collected from blood donors aged 18 years collected between March 2016 and July 2017 was conducted in the city of Mwanza. The sample size was calculated using the Kish Leslie formula a prevalence of 12.2% from a previous study in Burkina-Faso was fitted in the formula18. The minimum sample size was 169, however a total of 228 sera were retrieved and include into the study. Sera were conveniently selected until desired sample size was reached. All sera with incomplete information were excluded from the study. Socio-demographic and other relevant information were recorded from preexisting database. The protocol to conduct this study was approved by the joint CUHAS/BMC research ethics and review committee (CREC) with ethical clearance number CREC 340/2017.

Laboratory processing of the specimens

Detection of specific HCMV IgM antibodies was done using commercial IgM µ capture enzyme linked immunosorbent assay (ELISA) according to manufacturer's instructions (PishtazTeb, Tehran, Iran). The assay has sensitivity and specificity of >99%19–22.

Data analysis

Data was analyzed by using STATA version 13. Continous variables were summarized as median with interquartile range while categorical variables were summarized as proportions. Chi square test was used to test association between outcome and independent variables

Results

The median age of the study participants was 19(IQR:18–23) years. Male sex was more predominant 84.65% (193/228) compared to female sex. Most of the participants, 74.12% (169/228) were students (Table 1).

Table 1

Characteristics of 288 blood donors attended at Victoria zone blood transfusion center in Mwanza, Tanzania

Participant characteristics		Number(Frequency)	Median (%)
Age		228	19 (IQR:18–23)
Sex:	Female	35	15.35%
	Male	193	84.65%
Occupation:	Workers	59	25.88%
	Students	169	74.12%
CMV IgM:	Negative	205	89.91%
	Positive	23	10.09%

The overall seroprevalence of specific HCMV IgM antibodies was found to be 23/228 (10.09%, 95% CI: 6–14). Out of 35 females, 2(5.7%) were IgM seropositive compared to 21(10.9%) of 193 males, P=0.35. Regarding occupation, 13.6% of 59 workers were seropositive compared to 8.9% of 169 students, P=0.304. The seroprevalence in age (years) groups; 16–25, 26–45 and 36–45 were 10.1%, 12.9% and 9.1%, respectively. On Wilcoxon ranksum (Man Whitney) test, there was no significant difference in age among positive cases and negative cases (19, IQR: 18–25 vs. 19, IQR: 18–22, P>0.05). Among sociodemographic characteristics assessed, none of them was found to be associated with HCMV IgM seropositivity among blood donors in the Lake Victoria zone blood transfusion center.

Discussion

This is the first study to establish the seroprevalence of specific HCMV IgM antibodies among blood donors in the Lake Victoria zone blood transfusion center. In the current study, a significant proportion of blood donors had specific IgM antibodies which often indicate acute or recent infections. Results from the current study are comparable to a previous report from Ouagadougou Burkina Faso which reported the prevalence of 12.2%18. In comparison to other previous studies, the reported seroprevalence in this study is lower than 85% and 28% reported in North-West Iran and in Nigeria16,23. On the contrary, the reported seroprevalence in this study is indeed high compared to the previous reports in India and Kenya which documented the seroprevalence of 0.07% and 3.6%, respectively15,24. The possible explanation for these variations could be geographical variations, climatic and socio-economic backgrounds which might influence the epidemiology of the HCMV25,26. Another explanation could be sensitivity and specificity of the test used in different studies. In the current study, IgM µ capture ELISA was used with sensitivity and specificity of 100% and 99%, respectively which might be different from other studies. Considering the fact that HCMV is not routinely screened in most of resource limited countries where the prevalence is high, this might increase the risk of transmission to vulnerable groups such as immunocompromised patients, neonates and pregnant women. This underscores the need to consider screening for HCMV in donated blood before transfusion particularly in vulnerable groups.

In the current study, none of the socio-demographic factors assessed was found to be associated with HCMV IgM seropositivity. This could be explained by the fact that the current study used achieved sera which might limit accessibility of other information from the study participants. Further studies to explore more on the risk factors are recommended in this setting.

Conclusion and recommendations

A substantial proportion of blood donors in the Lake Victoria zone blood transfusion centre is acutely infected with HCMV which calls for the need to consider screening for HCMV before the donated blood is transfused to recipients especially vulnerable groups. Further studies to explore more on the risk factors are highly recommended in this setting.