Seroprevalence of parvovirus B19 and its clinical effect among anaemic SCA patients in Northeastern Nigeria

Abstract

Sickle cell anaemia (SCA) is a globally widespread genetic disorder affecting 5% of the world’s over 6 billion people. Parvovirus infection and the resulting aplastic crisis is a recognised complication in individuals with SCA. Aplastic crisis increases the need for blood transfusion and its attendant risk of Transfusion Transmissible Infection (TTI). Hence there is a vicious cycle in which Parvovirus B19 causes aplastic crisis which in turn causes increased transfusion need; and transfusion increases risk of transfusion transmissible infection in which parvovirus B19 is included in certain parts of the world. Sickle cell anaemia is associated with foetal death and infection with parvovirus B19 increases the risk to early mortality. The objective of this study was to determine the seroprevalence of parvovirus B19 among SCA and compare with that of controls in the study area. Furthermore clinical and laboratory profile of subjects were analysed to identify possible correlation with parvovirus B19 seropositivity and explore the possibility of involvement of white cell and platelets. A total of 90 subjects comprising 45 consecutive SCA case subjects and 45 age- and sex- matched non SCA controls were studied in a cross sectional comparative study. Ten millilitres of blood was drawn from the antecubital fossa of each subject after obtaining informed consent. The 10mls of blood was divided into two aliquots, 4.5 mls was added into EDTA anticoagulated bottle and was used for basic complete blood count (CBC), while the remaining 5mls was added into a plain specimen container allowed to clot and serum obtained to test for anti- parvovirus B19 IgG and IgM using an immunochromatography based technique specifically BIOCARD TM Parvo B19 diagnostic test kit. There was male preponderance in the study. The SCA subjects comprised 26 males and 19 females (male to female ratio = 1.4:1), while the non- SCA controls comprised 25 males and 20 females (male to female ratio 1.3:1).. The analysis of anti- parvovirus B19 IgG antibody revealed a prevalence of 23.3% among SCA cases with 18.9% among controls. The haematological profile is not affected by IgG seropositivity. However pregnancy outcome revealed that the total number of stillbirths is 12 among IgG seropositive SCA cases which is higher than the 6 encountered in IgG seronegative SCA subjects; the difference is statistically significant (p=0.04).