Parvovirus B19 infection and severe anaemia in Kenyan children: a retrospective case control study

Abstract

BackgroundDuring acute Human parvovirus B19 (B19) infection a transient reduction in blood haemoglobin concentration is induced, due to a 5-7 day cessation of red cell production. This can precipitate severe anaemia in subjects with a range of pre-existing conditions. Of the disease markers that occur during B19 infection, high IgM levels occur closest in time to the maximum reduction in haemoglobin concentration. Previous studies of the contribution of B19 to severe anaemia among young children in Africa have yielded varied results. This retrospective case/control study seeks to ascertain the proportion of severe anaemia cases precipitated by B19 among young children admitted to a Kenyan district hospital.MethodsArchival blood samples from 264 children under 6 years with severe anaemia admitted to a Kenyan District Hospital, between 1999 and 2004, and 264 matched controls, were tested for B19 IgM by Enzyme Immunosorbent Assay and 198 of these pairs were tested for B19 DNA by PCR. 536 samples were also tested for the presence of B19 IgG.Results7 (2.7%) cases and 0 (0%) controls had high B19 IgM levels (Optical Density > 5 × cut-off value) (McNemar's exact test p = 0.01563), indicating a significant association with severe anaemia. The majority of strongly IgM positive cases occurred in 2003.10/264 (3.7%) cases compared to 5/264 (1.9%) controls tested positive for B19 IgM. This difference was not statistically significant, odds ratio (OR) = 2.00 (CI95 [0.62, 6.06], McNemar's exact test p = 0.3018. There was no significant difference between cases and controls in the B19 IgG (35 (14.8%) vs 32 (13.6%)), OR = 1.103 (CI95 [0.66, 1.89], McNemar's exact test, p = 0.7982), or the detection of the B19 DNA (6 (3.0%) vs 5 (2.5%)), OR = 1.2 (CI95 [0.33, 4.01], McNemar's exact test p = 1).ConclusionsHigh B19 IgM levels were significantly associated with severe anaemia, being found only among the cases. This suggests that 7/264 (2.7%) of cases of severe anaemia in the population of children admitted to KDH were precipitated by B19. While this is a relatively small proportion, this has to be evaluated in the light of the IgG data that shows that less than 15% of children in the study were exposed to B19, a figure much lower than reported in other tropical areas.

The effects of co-infection with human parvovirus B19 and Plasmodium falciparum on type and degree of anaemia in Ghanaian children

“…The association of B19V with aplastic crisis is extensively reported but its role in malaria remains a controversy. This study confirms studies conducted in Nigeria [41] , Papua New Guinea [43] , and Kenya [42] , where B19V co-infection with malaria was found to contribute significantly to anaemia. This observation could be explained by the changes in the climatic conditions as well as absence of underlying conditions to exacerbate severe anaemia.…”

“…The approach used in this study was designed to systematically determine within different cross-sections of children with varying degrees of anaemia the potential of B19V and/or co-infection with B19V and malaria to cause a rather more severe form of anaemia. This study is in contrast to other B19V studies in which investigations were structured to prove that co-infection with B19V and malaria had a similar potential by investigating only cross-sections of children with severe anaemia and those without severe anaemia [41][42][43][44] . This study is the first to evaluate B19V's contribution to anaemia in a malaria endemic area in this manner.…”

“…In another study, the prevalence of B19V DNA among Ghanaian children hospitalized for severe anaemia was 11.5% [45] . Similar studies from Papua New Guinea and Kenya have reported that B19V contributes to severe anaemia among children in malaria endemic areas [42,43] . However, studies conducted among Malawian children report that B19V may not be a significant contributor to severe anaemia [12,70] .…”

“…It has been hypothesized that, since erythroid precursor cells represent a common target for both B19V and P. falciparum, a predisposing factor to viral invasion and infection could be a depression of cellular immunity induced by P. falciparum [40] . A high incidence of co-infection with malaria and B19V and an association with anaemia has been reported in malaria endemic areas [41][42][43][44][45] . In addition, some case studies have also reported of B19V induced severe anaemia following malaria infection and successful treatment with antimalarials [46][47][48][49][50] .…”

Safety and immunogenicity of a candidate parvovirus B19 vaccine

“…In individuals with underlying hemolytic disorders, parvovirus B19 infection results in transient aplastic crisis (TAC), a temporary cessation of red blood cell production with severe worsening of anemia, which is occasionally fatal [1, 4]. Similarly, parvovirus B19 infections play a significant role in the etiology of severe anemia in areas where malarial is endemic and contributes to the morbidity and mortality associated with severe anemia in such regions [5, 6]. In immunosuppressed individuals, parvovirus B19 can persist and cause severe anemia and pure red cell aplasia.…”