Introduction

HCV was first discovered in 1989 and the antibody detection assay for screening was introduced in 1990.Prior to this, the risk of acquiring HCV through blood transfusion in the U.S.A. was 1 in 200 units. Following the improvement in HCV antibody testing, including the introduction in 2002 of nucleic acid testing, the risk has fallen dramatically to 1 in 2 million donations^1,2.

In the U.S.A. and Europe, before 1990, majority of cases of HCV infection were acquired through I.V. drug use and transfusions³. Prior to adequate testing techniques for HCV infection, 10% of transfusion recipients, according to some studies, acquired the infection⁴. This made it the commonest cause of transfusion related hepatitis.

The prevalence of hepatitis C and the commonest mode of transmission among Nigerians are unknown, but recent studies across the country among blood donors show a prevalence ranging between 0.4% and 10.4% depending on locality^5-9. However, routine screening for hepatitis C in blood donors is only carried out in major public health institutions in Nigeria today; because of unavailability of screening kits and trained manpower in smaller health institutions. This has obvious grave short and long term health implications on the populace; considering that chronic hepatitis C is a progressive disease which leads to death through liver failure or hepatocellular carcinoma (HCC) and also predisposes to non-Hodgkin’s lymphoma (NHL), multiple myeloma (MM), and renal cell carcinoma (RCC) ^10-12 It is not known whether blood group, age or sex constitute risk factors or are correlated with HCV seropositivity among apparently healthy individuals. Studies have been done which agree with or refute the above^13,14.

This study is intended to look at the prevalence of this potentially morbid illness amongst blood donors in Nnewi and assess its association with the blood group, age, and sex of these donors; bringing to light the possible public health implications to guide government planners and policy makers.

Materials And Methods

Donor Selection

Laboratory analysis

Statistical analysis

Results

Of the 1229 blood donors screened in our center for HCV between 2005 and 2009, 25 were found to be seropositive giving an overall prevalence rate of 2.0%. There were 1001 males and 228 females with a male to female ratio of 4.4:1. The mean age of the blood donors was 30.1±8.5years and the median age was 28years (range, 17-70 years). The prevalence of HCV in males was 2.0% and that in females was 2.2%. This difference was not statistically significant (OR = 0.91, p=0.85) (Table 1).

Figure 1

Table 1: Prevalence Of HCV Positivity According To Gender

OR = Odds ratio, CI = Confidence interval

The blood donors were grouped by age. The numerically largest age group consisted of donors aged 21-30years (662/1229=53.9%). However, the prevalence of HCV was found to be lowest in this group (1.4%). We noted that the prevalence of HCV increased after the age of 30years with the highest prevalence (3.2%) recorded in those 31-40years old and 51-70years old respectively. Nevertheless, this increase was not linear and was not statistically significant (chi sq. = 4.054, p=0.4) (Table 2).

Figure 2

Table 2: HCV Antibody Status Among Different Age Group Of Blood Donors

The prevalence of HCV in relation to donors’ blood group is shown in table 3. Majority of the blood donors were O RhD-positive (66.9%). This was followed in descending order by A RhD- positive (19.4%), B RhD-positive (8%), O RhD- negative (4.3%), A RhD-negative (0.9%), B RhD-negative (0.4%) and AB RhD-positive (0.2%). Most of the blood donors who were HCV positive were O RhD- positive (20 subjects), the others were A RhD-positive (3 subjects), A RhD-negative and O RhD-negative (1 subject each). However, the prevalence of HCV seropositivity was documented to be highest in blood group A RhD-negative donors (1/11=9.1%). HCV sero-positivity was not documented in donors who were B RhD-positive, B RhD-negative, and AB RhD-positive.

Figure 3

Table 3: Blood Group Distribution Of HCV Antibody Status

The results of Pearson’s bi-variate correlation showed no significant statistical association between HCV, gender, age group and blood group of donors (p>0.05) respectively. A significant correlation was observed between gender and age group of blood donors (p<0.05) (Table 4).

Figure 4

Table 4 - Pearson’s Bi-Variate Correlation Between Variables Tested Among The 1229 Participant

*Correlation is significant at the 0.01 level (2-tailed)

As the age group of blood donors increases, the greater the frequency of male donors compared to female donors (Table 5).

Figure 5

Table 5: Relationship Between Gender And Age Group Of Blood Donors

Discussion

Viral hepatitis is one of the common complications of blood transfusion¹⁶. Hepatitis C has been described as a major cause of non- A non-B hepatitis since its characterization in 1989 with parenteral transmission especially through blood transfusion and intravenous drug use^17-18. This study conducted in Nnewi, a highly commercial city in Anambra state, south-east Nigeria, established the sero-prevalence of anti-HCV antibodies in 1229 blood donors evaluated between 2005 and 2009. The overall sero-prevalence of HCV was 2.0%. Parameters such as donor blood group, age and sex were found not to be significantly correlated with HCV status. Gender however, was found to be significantly correlated with age.

This prevalence rate though low, confirmed that HCV infection is prevalent among healthy blood donors in Nnewi, Nigeria. It is higher than the prevalence rate of 0.4% reported in Kano, North central Nigeria¹⁹ but lower than the prevalence rates of 5% and 12% reported in Port-Harcourt and Benin city, both in South-south Nigeria respectively^14,20. These two centers unlike our center depend mostly on commercial blood donors for blood replacement. Donation of blood in our center is mainly by family replacement. These families depend on voluntary blood donation from relations and friends and this may explain the lower prevalence rate documented from our study. Nevertheless, in Nigeria generally, studies have shown that compared to HBV infection, HCV infection is less prevalent and plays a minor role in the pathogenesis of Chronic liver disease^21-22.

In Africa, HCV sero-prevalence rates contrast sharply between West and North Africa. While very low prevalence rates were found among blood donors in Dakar Senegal (0.8%)²³ and Ghana (0.9%)²⁴, very high prevalence rates were reported among blood donors in Egypt (19.2%²⁵, 22.5%²⁶). Indeed, Egypt is reported to have the highest prevalence of HCV (predominantly genotype 4) in the world and this has been attributed to previous public health eradication schemes for Schistosomiasis³. HCV seroprevalence rates from most developed nations are, not surprisingly, very low. The lowest prevalence rate was reported from England (0.1%)²⁷ compared to Spain (0.3%)²⁸, Germany (0.65%)²⁹ and New York (1.8%)³⁰.

The prevalence of HCV increased after the age of 30years with highest rates in those aged 31-40years and 51-70years. This is similar to previous observations that HCV prevalence rate increases with increasing age reaching a peak in persons above 30 years of age ^31-32 but at variance with a peak age prevalence of 21-30years reported by Jeremiah et al ¹⁴.

Although HCV is known to be transmitted by non- percutaneous modes such as sexual activity, transmission by this route is much lower than percutaneous modes through blood and injection drug abuse^33-34. The mean age of blood donors in this study is above 30years and it highlights the need to recruit younger donors even in centers were voluntary donation is the mainstay of blood replacement and to screen all blood donors irrespective of age. This proposal is in line with the new strategy adopted by the international community to recruit blood donors less than 30years of age to ensure provision of safe blood³⁵. The implementation of this policy has been shown to reduce the prevalence of blood transmissible infections such as human immunodeficiency virus (HIV) and hepatitis³⁵.

Blood group O rhesus positive was the most frequently encountered (822/1229, 66.9%). This finding is not unexpected as there is usually a high demand for blood group O which is the most common blood group in the general population¹⁴.

Pearson’s bi-variate correlation showed a negative correlation between HCV sero-prevalence, sex, age and donor blood group, but these were not statistically significant (p>0.05). It seems from these findings that demographic and genetic factors which determine blood group does not influence HCV sero-positivity as was earlier reported by Busch et al³⁶. Interestingly, the relationship between age and gender of blood donors was statistically significant (p<0.05). Age, gender and donor category (not included in this study) had previously been documented by various authors to be important factors in controlling HCV sero-prevalence among blood donors^14,37. Our results agree with this deduction.

In conclusion, the results of this study showed that hepatitis C is prevalent among healthy blood donors in Nnewi though low compared to what has been reported in some regions of Nigeria. All blood donors should be screened for anti-HCV regardless of demographic indices such as age and gender.

Acknowledgement

We are indebted to the donors and staff who presented or work at the Nnamdi Azikiwe University Teaching hospital blood bank; and most of all to God who has made this work possible.