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Parvovirus B19 Infection Contributes to Severe Anemia in Young Children in Papua New Guinea

  1. James Wildig1,a,
  2. Pascal Michon2,a,
  3. Peter Siba3,
  4. Mata Mellombo2,
  5. Alice Ura2,
  6. Ivo Mueller2,3 and
  7. Yvonne Cossart1
  1. 1Department of Infectious Diseases and Immunology, University of Sydney, Australia;
  2. 2Papua New Guinea Institute of Medical Research, Madang, and
  3. 3Papua New Guinea Institute of Medical Research, Goroka
  1. Reprints or correspondence: Dr. Yvonne Cossart, Dept. of Infectious Diseases and Immunology, University of Sydney, D06, Sydney NSW 2006, Australia (ycossart{at}infdis.usyd.edu.au)
 
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Abstract

BackgroundSevere anemia (hemoglobin level, <50 g/L) is a major cause of death among young children, and it arises from multiple factors, including malaria and iron deficiency. We sought to determine whether infection with parvovirus B19 (B19), which causes the cessation of erythropoiesis for 3–7 days, might precipitate some cases of severe anemia

MethodsArchival blood samples collected in the Wosera District of Papua New Guinea, from 169 children 6 months–5 years old with severe anemia and from 169 control subjects matched for age, sex, and time were tested for B19 immunoglobulin M (IgM) by enzyme immunoassay and for B19 DNA by nested polymerase chain reaction (PCR). A total of 168 separate samples from children in the Wosera District were tested for B19 IgG

ResultsA strong association between acute B19 infection (positive by both IgM and PCR) and severe anemia was found (adjusted odds ratio, 5.61 [95% confidence interval, 1.93–16.3]). The prevalence of parvovirus B19 IgG reached >90% in 6-year-olds

ConclusionsB19 infections play a significant role in the etiology of severe anemia in this area of malarial endemicity. Given the high levels of morbidity and mortality associated with severe anemia in such regions, the prevention of B19 infection with a vaccine might be a highly effective public health intervention

Severe anemia (hemoglobin level, <50 g/L) is very common among young children in regions where malaria is endemic [1], accounting for an estimated 1 million child deaths per year [2]. The etiology of severe anemia in these children is complex, with a variety of factors—including malaria and iron deficiency—contributing [3]

Parvovirus B19 (B19) is common worldwide; antibody studies have indicated that >50% of people are infected during childhood. Higher rates have been reported among children in some tropical areas [4, 5]. Outbreaks occurring at 3–6-year intervals have been described [5, 6]

B19 is tropic for red blood cell precursors in the bone marrow, with acute infection causing impaired erythropoiesis for 7–10 days and complete cessation for 3–7 days. The effect of this on hemoglobin level varies by individual. In healthy adults, a decrease in hemoglobin level of ∼20 g/L will occur [7, 8], whereas larger decreases have been described in persons with iron deficiency [9] and malaria [10, 11]. In persons with sickle-cell disease [12] and other hemolytic disorders, a precipitous decrease in hemoglobin levels can be induced through the combination of a high rate of red blood cell destruction and complete cessation of red blood cell production caused by B19. This has been termed “transient aplastic crisis.”

After initial contact with B19, viral replication leads to a dense viremia that starts to decline once specific IgM is produced on day ∼9 [8]. Virus-induced bone-marrow suppression begins to recover on day ∼16, and the lowest hemoglobin level occurs soon after (figure 1) [7, 13, 14]. Thus, the simultaneous detection of B19 IgM and DNA is strongly indicative of acute infection. B19 IgM usually becomes undetectable after 2–4 months, depending on the initial level of response [15], although persistence for up to 9 months has been reported [16]. The rate of decrease in viremia is less predictable. The half-life of B19 in blood is not known, but, even though the virus may become undetectable soon after infection, clinical studies using highly sensitive nested or real-time polymerase chain reaction (PCR) methods have shown that B19 DNA can often be detected 6 months or even longer after the onset of illness in patients who have become IgM negative [17]. After infection, IgG persists; thus, a person usually is infected only once in a lifetime

Figure 1
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Figure 1

Timing of changes in clinical and virological parameters during acute parvovirus B19 infection in the immunocompetent individual. Data are from various sources [7, 12–15]. RBC, red blood cell

In 1990, it was suggested that B19 infection might be a causative factor in some cases of severe anemia among young children in areas where malaria is endemic [4]. In that study, which was conducted in the Republic of Niger and apparently coincided with a B19 infection outbreak, 54% of children with severe anemia (hematocrit level, <20%) showed evidence of recent B19 infection. No control group was assessed, so rates of B19 infection in children with and without anemia could not be compared. Two subsequent studies, from Malawi [18] and Kenya [3], found little evidence of acute B19 infection in any children (anemic or control) over the course of 1 year of testing. In the present article, we present the results of a retrospective case-control study linking B19 infection to severe anemia in a highly malarious area [19] of Papua New Guinea (PNG)

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Patients, Materials, and Methods

Both case patients and control subjects were selected from archival blood samples collected between 1996 and 2002 from children 6 months–6 years old who presented with presumptive malaria (measured fever or reported febrile illness with no obvious respiratory cause) at 2 health centers in Wosera District, East Sepik Province, PNG. These samples had been collected as part of ongoing routine malaria morbidity surveillance at the PNG Institute of Medical Research malaria vaccine trial site. Hemoglobin was measured at the time of sample collection using the HemoCue system (HemoCue). Malarial infection was defined as the detection of malarial parasites by microscopic examination of the blood film; the different species of malaria parasite were distinguished and examined individually in the statistical analyses. All children were treated in accordance with PNG national guidelines for malaria infection and severe anemia (antimalarial treatment and oral or intramuscular iron supplementation)

After samples lacking hemoglobin readings were excluded, there were 11,441 samples with age, sex, blood-slide readings, and hemoglobin measurement data available. Children with hemoglobin levels of ⩽50 g/L (the World Health Organization [WHO]–recommended cutoff for severe anemia]) were selected as case patients. A control group of children with hemoglobin levels of >50 g/L was selected and matched for age (83% within 1 month), sex, and time (most within 3 months and all within 1 year). When spoiled or lost samples were excluded, 169 matched pairs of samples were available for testing. The mean age of case patients and control subjects was 2.87 and 2.84 years, respectively, and 47.9% of children in both groups were male (table 1). These pairs were tested for the presence of both B19 IgM and DNA, because either can be a unique marker of recent B19 infection, and the finding of both in the same specimen is strongly indicative of acute infection. A total of 168 separate consecutive samples from children 6 months–10 years old who presented to the same health centers in late 2000 with presumptive malaria were subsequently selected for testing for B19 IgG

Stored plasma from the selected samples was tested for B19 IgM or IgG using the Biotrin Parvovirus B19 IgM or IgG EIA kit (Biotrin International). The reaction wells were washed with 200–220 μL of wash solution per use, depending on the available equipment. Plasma samples that were stained with red blood cells during the collection or storage process were included. Otherwise, specimens were tested in accordance with the manufacturer’s instructions. The IgM EIA kit has a reported sensitivity of 86% and a specificity of 95% [20], and the IgG EIA kit has a reported sensitivity and specificity of 100% [21]. These kits have been shown to have good specificity when they are tested on serum samples from people with other infections [22] and in comparison with other kits [23]. All case-control samples were tested for IgM in duplicate (or in triplicate, if the first 2 results differed). Case and control specimens were tested side by side in 96-well plates. Because the samples were stored at a remote field location, a portable Axiom M6 Miniphotometer with a 450-nm filter (Axiom) was used to measure the optical density of the test reactions. To allow for the measured precision of the reading device, the equivocal range was extended to 0.8–1.2 times the cutoff optical density

DNA samples were extracted separately from plasma and erythrocyte pellets of the selected samples (when available) using the QIAmp 96 DNA blood kit (Qiagen). Two oligonucleotide primer pairs were designed on the basis of the B19 genomic sequence (GenBank accession number NC_000883) and used in a nested-PCR approach. Briefly, 1 μL of DNA template (or PCR product from first-round PCR) was amplified by PCR with 0.5 U of Taq DNA polymerase (Invitrogen) and supplied buffer, 1.5 mmol/L MgCl2, and 200 μmol/L each dNTP in 2 consecutive 15-μL reactions, using oligonucleotide primers (400 nmol/L each) specific for human erythrovirus genotype 1 (B19), as follows: first-round forward primer B19-1F (5′-CTG TGG TTT TAT GGG CCG CC-3′) and reverse primer B19-1R (5′-AGG TGT GTA GAA GGC TTC TTC CC-3′), followed by nested forward primer B19-2F (5′-GGG AAA AGC TTG GTG GTC TGG G-3′) and reverse primer B19-2R (5′-GCG CGG GGT TTC AGT GTT CC-3′). Both reactions consisted of 2 min at 94°C and 35 cycles of 30 s at 94°C, 30 s at 60°C, and 1 min at 72°C. To ensure specificity, PCR products of the expected sizes for both reactions were originally sequenced and checked with the DNA database, to verify that the appropriate target was amplified. A sample with a positive PCR result in either plasma or the erythrocyte pellet was regarded as positive for statistical analysis

Statistical analysesTo account for matching, the case-control data were analyzed with either McNemar’s χ2 test or with conditional logistic regression. Correspondence between PCR and EIA results and the prevalence of malarial infections was tested using Pearson’s χ2 test. All analyses were done using Stata statistical software (version 7.0; StataCorp). Stata software uses an uncorrected numerator for the McNemar’s test—that is, (n12-n21)2. An age-specific prevalence curve for IgG data was fitted using a generalized additive model for binomial data involving fourth-order splines of the S-PLUS package (version 6.0; Insightful)

Ethics approvalEthics approval for the study was given by the PNG Medical Research Advisory Committee, and that for the IgM testing was given by the University of Sydney Human Ethics Committee

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Results

For each specimen, 2 independent B19 diagnostic results were obtained: the presence or absence of B19 IgM or DNA. Positive results for both in the same specimen were regarded as strongly indicative of an acute B19 infection

Of 169 case patients with hemoglobin levels of <50 g/L, 51 (30.2%) were positive, 95 (56.2%) were negative, and 23 (13.6%) had equivocal results for B19 IgM, whereas, of control subjects, 21 (12.4%) were positive, 126 (74.6%) were negative, and 22 had equivocal results (13.0%). All analyses were done once with equivocal readings considered to be negative and once with all case-control pairs with equivocal IgM values omitted from the analysis. Because the results of both analyses did not differ significantly (data not shown), only results from the former analyses (equivocal = negative) will be presented

Acute B19 infection, defined as both IgM EIA and PCR positivity, showed the strongest association with severe anemia (odds ratio [OR], 5.0). Independently, only IgM positivity (OR, 3.0)—and not PCR positivity (OR, 1.25)—was significantly associated with severe anemia (table 2). If only the samples with the highest optical-density values in IgM testing (i.e., >3 times the cutoff value) were considered, 25 of 26 were from case patients, and 21 of these were also positive by PCR (figure 2). No clear temporal clustering of either IgM- or PCR-positive samples was observed

Figure 2
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Figure 2

Evidence of acute parvovirus B19 infection in case patients and control subjects. Optical density readings for B19 IgM testing (as multiples of the cutoff optical density value) were plotted against hemoglobin (Hb) levels for case patients and control subjects. Gray-shaded area, equivocal range (0.8 < OD < 1.2); black points, polymerase chain reaction (PCR)–positive samples; white points, PCR-negative samples

In the case patients, but not in the control subjects, PCR positivity was significantly associated with IgM positivity (table 3). Among the case patients, 14.8% were positive for IgM only, 11.8% were positive for B19 PCR only, and 15.4% were positive for both, compared with 8.9%, 19.5%, and 3.6%, respectively, in control subjects (χ2=19.5 [df 3]; P<.001). The ORs (vs. double-negative samples) for association with severe anemia were 5.32 for both IgM and PCR–positive results, 1.89 for IgM-positive results only (P=.075), and 0.61 for PCR-positive results only (table 4)

Figure 3
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Figure 3

Age-specific prevalence of parvovirus B19 IgG in 168 children from the study area who were <10 years old. All children were selected from among patients with presumptive malaria attending the Kunjingini health center during the second half of 2002. The age-specific mean (solid line) and binomial SEs (dashed lines) were predicted using fourth-order regression splines. White circles, IgG-negative children; black circles, IgG-positive children

Table 1
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Table 1

Comparison of age, hemoglobin (Hb) level, and malarial parasitemia in case patients and control subjects

Table 2
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Table 2

Association of parvovirus B19 IgM and polymerase chain reaction (PCR) positivity with severe anemia

Table 3
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Table 3

Prevalence of viremia in case patients and control subjects with and without parvovirus B19–specific IgM antibody

Table 4
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Table 4

Risk of severe anemia associated with parvovirus B19 and Plasmodium infection status

Malarial infections were significantly more frequent in case patients (150/169 [88.8%]) than in control subjects (108/169 [63.9%]) (P<.0001). Significantly more of these were P. falciparum infections (131/150 [87.3%]) than non–P. falciparum infections (76/108 [70.4%]) (P=.001) (table 1). Both P. falciparum and non–P. falciparum infections were associated with an increase in risk of severe anemia, compared with that in uninfected children (OR, 5.75 [95% confidence interval {CI}, 2.93–11.26]; P<.001 for P. falciparum infection and OR, 2.16 [95% CI, 0.94–5.00]; P=.07 for non–P. falciparum infection)

We then investigated the interaction between B19 and malarial infections in detail (table 4). Multivariate analyses showed that the risks of severe anemia associated with Plasmodium and B19 infections were independent of each other (χ2=7.57 [df 6]; P=.27, likelihood-ratio test). Acute B19 infection (i.e., PCR- and IgM-positive results) was associated with an increase in the risk of severe anemia comparable to that associated with P. falciparum infections (multivariate OR, 5.53 vs. 5.84) (table 4)

In the serum samples from 168 children 1–10 years old from the study area, the age-specific prevalence of B19 IgG was found to increase rapidly during the first years of life (figure 3), with 60% of children <2 years old already positive for B19 IgG. Levels continued to increase until age 6 years, when the prevalence of IgG plateaued at ∼90%

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Discussion

The present results demonstrate that acute B19 infection is a major contributor to severe anemia in young children in the study area, where malaria is endemic. Indeed, the association found between acute B19 infection (defined as both B19 IgM and PCR positivity) and severe anemia (multivariate OR, 5.53) is comparable to that found between P. falciparum infection (a leading cause of anemia in areas of endemicity) and anemia (multivariate OR, 5.84)

This finding contrasts the situation in developed countries, where B19-induced severe anemia is rare, except in individuals with hemolytic disorders. A possible reason for this geographical difference is that, in tropical areas of developing countries, an underlying mild-to-moderate level of anemia is very common in young children [3]. Cross-sectional surveys in the Wosera and neighboring populations of PNG found that 5%–11% of children had a hemoglobin levels of <7 g/dL (I.M., unpublished data). This anemia arises from multiple factors, such as malnutrition (including iron deficiency), current and past malaria, and other infections, including hookworm [24]. B19 infection causes a 20-g/L decrease in hemoglobin level, even in previously healthy adult volunteers without hemolytic disease [7]. Thus, when acute B19 infection strikes children in a population where anemia is common, the resulting decrease in hemoglobin level, when superimposed on a preexisting moderate level of anemia, may be the proverbial “last straw” that pushes an already low hemoglobin level below the 50-g/L level that defines severe anemia, even in the absence of hemolysis. By contrast, children in developed countries with normal hemoglobin levels are untroubled by a transient 20-g/dL decrease in hemoglobin level. Clearly, any children in PNG with a hemolytic disorder would have an even larger decrease in hemoglobin levels if they developed B19 infection, and they might be even more prone to B19-induced severe anemia. Although hemoglobin S is not known to occur in PNG, glucose-6-phosphate-dehydrogenase (G6PD) deficiency has been noted to be present in 8.7% of people in a nearby region [25]. It is thus conceivable that at least part of the excess risk of severe anemia after B19 infection is concentrated in children with G6PD deficiency. Other red blood cell polymorphisms that are common in PNG include the Gerbich blood group and α- or β-thalassemia [26]. However, among 306 children with genotypic data available, Gerbich blood group (band 3 deletion) and α-thalassemia were not significantly associated with an increase in the risk of severe anemia associated with B19 infection (P.M., unpublished data)

Data on the prevalence of B19 IgM and DNA in children living in tropical areas is very limited. Although studies of adult blood donors in the United States have indicated a prevalence of B19 IgM of ∼1%, we found a much higher prevalence of B19 IgM, 12%, in the control population. The characteristics of our control group may offer some explanation for this, in that they were children, they had had a recent febrile illness, and they lived in PNG. IgG studies have indicated that B19 infection is much more common in children living in tropical areas. Indeed, our IgG testing showed that 90% of children in the Wosera District had evidence of previous B19 infection by age 6 years. Furthermore, B19 causes a febrile illness, so the febrile children used as control subjects were more likely to have had IgM from an acute infection than were asymptomatic children. These factors help to explain the high prevalence of IgM and, thereby, the high number of equivocal results in our study. With a high rate of positive results, numerous samples will be from children who were recently positive and whose antibody levels are decreasing, passing through the equivocal range as they fall

Some studies have indicated that IgM testing yields more false-positive results in populations with other infections or autoantibodies. It is true that a number of the children sampled in the present study were likely to have had other infections, whereas the rate of autoantibodies in this population was not known. However, although older IgM assays had problems with specificity under these circumstances, the Biotrin B19 IgM and IgG EIA kits that we used have been shown to perform well with regard to specificity in such samples. Moreover, because case patients and control subjects were selected from the same population, the false-positive rates should have been similar in both and should not have had a major influence on the correlation found between B19 infection and severe anemia

The introduction of sensitive PCR tests for B19 in recent years has revealed that many patients retain detectable DNA for weeks or months after specific IgM becomes undetectable, at ∼3 months after infection [13, 27]. This may well explain the high prevalence of B19 DNA that we found in both case patients and control subjects. The average age of the children in our study was a little less than 3 years, when the prevalence of B19 IgG is already 60%. Assuming an added PCR persistence of 3 months the after the loss of IgM, protection for the first 6 months of age by maternal antibody, and an endemic pattern of infection, random testing of 3-year-olds in this environment would be expected to detect B19 DNA in 10% of them. We detected a not-dissimilar rate of 15.6%

Although many of the children with severe anemia tested positive for both B19 IgM and DNA, our study revealed numerous children who tested positive for only 1 of the 2. Given the complex temporal nature of the association between levels of viremia and IgM (figure 1), this is not surprising. At least 2 studies have demonstrated similar discrepancies between PCR and IgM test results in B19 infection, and those researchers recommended that both be used to diagnose of recent infection [14, 28]. The fact that the double-positive specimens showed the strongest correlation with severe anemia is expected, because this pattern of results is most likely to be seen around the time of hemoglobin suppression (figure 1)

Our finding of a significant association between acute B19 infection and severe anemia is reminiscent of the observations in Republic of Niger [4] but contrasts with the results of 2 other studies, from Malawi [18] and Kenya [3]. The fact that no association was found in these latter articles is likely to have stemmed from the short duration of the studies, which seems to have coincided with periods of low B19 transmission in the respective communities. Indeed, in the Malawi study, only 13% of children were B19 IgG positive, whereas, in the Wosera District, 60% of children were IgG positive by age 2 years. B19 often occurs in outbreaks separated by long periods of inactivity in both temperate and tropical areas [5, 29, 30]. The present study, which used archival samples collected over the course of a 6-year period, was able to achieve sufficient sample size to clearly demonstrate the association between B19 and severe anemia. However, the use of archival specimens also meant that the choice of control subjects in this retrospective analysis was limited by the availability of samples. Both case patients and control subjects were obtained from the same population of children presenting to health centers with presumptive malaria (i.e., recent fever with no obvious respiratory cause) between 1996 and 2002. Because acute B19 infection is accompanied by fever [31], it is likely to be more common among these clinical control subjects than among asymptomatic children in the community. The presumably higher prevalence of B19 infection in the available control subjects is likely to affect the estimates of the association of B19 infection with severe anemia in a conservative way, so the association is likely to be less pronounced in the present study than would have been the case if asymptomatic control subjects from the community had been used for comparison

Our study was based in the Wosera District, an area where malaria is highly endemic [19], and P. falciparum infection is an important risk factor for severe anemia. Interestingly, analysis of the results showed that the association of B19 infection with severe anemia is not altered by malarial infections and that the effects of both are additive. However, longitudinal studies in young African children have shown that hemoglobin levels are more closely related to average parasitemia during the preceding 90 days than to concurrent infections [32]. In addition, hematological responses after symptomatic malarial infections are often characterized by an initial decrease in hemoglobin levels, followed by an eventual recovery through increased erythropoiesis [33]. The interaction of B19 and acute malaria infections may thus be strongest when B19-induced erythropoietic suppression coincides with the period of increased erythropoiesis during the 1–4 weeks after treatment rather than with the acute malarial episode. The interactions between the 2 infections can thus only be properly investigated in longitudinal studies. The present results nevertheless indicate that controlling B19 infection is likely to lower the risk of severe anemia in all children, irrespective of their malaria status

Severe anemia is a major cause of morbidity and mortality in young children in areas where malaria is endemic [2]. Treatment with blood transfusion is limited in availability, is costly to patients and health-care facilities, and carries the risk of transmission of bloodborne pathogens, including HIV (even when anti-HIV screening is performed) [34]. Clearly, the prevention of severe anemia should be a major priority [35]. Further studies are needed to estimate the effects of B19 infection in other regions where malaria is endemic. However, the strength of the association between B19 and severe anemia observed in the present study indicates that the prevention of B19 infections is likely to result in a significant reduction in the burden of severe anemia in young children in these regions. Efforts to develop a safe and effective vaccine [36] against B19, which are already under way, should be strengthened, with the view of its possible use in the prevention of severe anemia among young children, alongside other measures, including malaria control and nutritional supplementation

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Acknowledgments

We thank the staff of the Papua New Guinea Institute of Medical Research in Goroka, Madang, and Maprik; the staff of the Department of Infectious Diseases, University of Sydney; Lawrence Rare and the health center surveillance nurses, for the collection of the samples; Thomas Adiguma, for managing the databases and helping with the selection of control subjects; and Livingstone Tavul, for helping with DNA extraction

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Footnotes

  • ↵(See the editorial commentary by Pasvol, on pages 141–2.)

  • ↵Potential conflicts of interest: none reported

    Financial support: Biotrin International, Ireland (parvovirus IgM and IgG test kits); PanBio Limited (Australia; assistance with shipping); University of Sydney, Faculty of Medicine Postgraduate Research Support Scheme; and Daphne Goulston Scholarship (travel assistance to J.W.)

  • ↵J.W. and P.M. contributed equally to the study

  • Received December 20, 2005.
  • Accepted February 16, 2006.
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References

  1. ↵
    1. Menendez C,
    2. Kahigwa E,
    3. Hirt R,
    4. et al
    . Randomised placebo-controlled trial of iron supplementation and malaria chemoprophylaxis for prevention of severe anaemia and malaria in Tanzanian infants. Lancet 1997;350:844-50.
    CrossRefMedlineWeb of Science
  2. ↵
    1. Murphy SC,
    2. Breman JG
    . Gaps in the childhood malaria burden in Africa: cerebral malaria, neurological sequelae, anemia, respiratory distress, hypoglycemia, and complications of pregnancy. Am J Trop Med Hyg 2001;64:57-67.
    Abstract/FREE Full Text
  3. ↵
    1. Newton CR,
    2. Warn PA,
    3. Winstanley PA,
    4. et al
    . Severe anaemia in children living in a malaria endemic area of Kenya. Trop Med Int Health 1997;2:165-78.
    CrossRefMedlineWeb of Science
  4. ↵
    1. Jones PH,
    2. Pickett LC,
    3. Anderson MJ,
    4. Pasvol G
    . Human parvovirus infection in children and severe anaemia seen in an area endemic for malaria. J Trop Med Hyg 1990;93:67-70.
    MedlineWeb of Science
  5. ↵
    1. Kelly HA,
    2. Siebert D,
    3. Hammond R,
    4. Leydon J,
    5. Kiely P
    . The age-specific prevalence of human parvovirus immunity in Victoria, Australia compared with other parts of the world. Epidemiol Infect 2000;124:449-57.
    CrossRefMedline
  6. ↵
    1. Serjeant GR,
    2. Topley JM,
    3. Mason K,
    4. et al
    . Outbreak of aplastic crises in sickle cell anaemia associated with parvovirus-like agent. Lancet 1981;2:595-7.
    CrossRefMedlineWeb of Science
  7. ↵
    1. Potter CG,
    2. Potter AC,
    3. Hatton CS,
    4. et al
    . Variation of erythroid and myeloid precursors in the marrow and peripheral blood of volunteer subjects infected with human parvovirus (B19). J Clin Invest 1987;79:1486-92.
    MedlineWeb of Science
  8. ↵
    1. Anderson MJ,
    2. Higgins PG,
    3. Davis LR,
    4. et al
    . Experimental parvoviral infection in humans. J Infect Dis 1985;152:257-65.
    Abstract/FREE Full Text
  9. ↵
    1. Kudoh T,
    2. Yoto Y,
    3. Suzuki N,
    4. et al
    . Human parvovirus B19-induced aplastic crisis in iron deficiency anemia. Acta Paediatr Jpn 1994;36:448-9.
    Medline
  10. ↵
    1. Lortholary O,
    2. Eliaszewicz M,
    3. Dupont B,
    4. Courouce AM
    . Parvovirus B19 infection during acute Plasmodium falciparum malaria. Eur J Haematol 1992;49:219.
    CrossRefMedlineWeb of Science
  11. ↵
    1. Urganci N,
    2. Arapoglu M,
    3. Kayaalp N
    . Plasmodium falciparum malaria with coexisting parvovirus B19 infection. Indian Pediatr 2003;40:369-70.
    Medline
  12. ↵
    1. Jones SE,
    2. Hodgson J,
    3. et al
    . Parvovirus infections and hypoplastic crisis in sickle-cell anaemia. Lancet 1981;1:664-5.
    MedlineWeb of Science
  13. ↵
    1. Patou G,
    2. Pillay D,
    3. Myint S,
    4. Pattison J
    . Characterization of a nested polymerase chain reaction assay for detection of parvovirus B19. J Clin Microbiol 1993;31:540-6.
    Abstract/FREE Full Text
  14. ↵
    1. Gallinella G,
    2. Zuffi E,
    3. Gentilomi G,
    4. et al
    . Relevance of B19 markers in serum samples for a diagnosis of parvovirus B19-correlated diseases. J Med Virol 2003;71:135-9.
    CrossRefMedlineWeb of Science
  15. ↵
    1. Clewley JP
    . Polymerase chain reaction assay of parvovirus B19 DNA in clinical specimens. J Clin Microbiol 1989;27:2647-51.
    Abstract/FREE Full Text
  16. ↵
    1. Searle K,
    2. Guilliard C,
    3. Wallat S,
    4. Schalasta G,
    5. Enders G
    . Acute parvovirus B19 infection in pregnant women—an analysis of serial samples by serological and semi-quantitative PCR techniques. Infection 1998;26:139-43.
    CrossRefMedlineWeb of Science
  17. ↵
    1. Lindblom A,
    2. Isa A,
    3. Norbeck A,
    4. et al
    . Slow clearance of human parvovirus B19 viremia following acute infection. Clin Infect Dis 2005;41:1201-3.
    Abstract/FREE Full Text
  18. ↵
    1. Yeats J,
    2. Daley H,
    3. Hardie D
    . Parvovirus B19 infection does not contribute significantly to severe anaemia in children with malaria in Malawi. Eur J Haematol 1999;63:276-7.
    MedlineWeb of Science
  19. ↵
    1. Genton B,
    2. al-Yaman F,
    3. Beck HP,
    4. et al
    . The epidemiology of malaria in the Wosera area, East Sepik Province, Papua New Guinea, in preparation for vaccine trials. I: Malariometric indices and immunity. Ann Trop Med Parasitol 1995;89:359-76.
    MedlineWeb of Science
  20. ↵
    1. Doyle S,
    2. Kerr S,
    3. O’Keeffe G,
    4. O’Carroll D,
    5. Daly P
    . Detection of parvovirus B19 IgM by antibody capture enzyme immunoassay: receiver operating characteristic analysis. J Virol Methods 2000;90:143-52.
    CrossRefMedlineWeb of Science
  21. ↵
    Parvovirus B19 IgG enzyme immunoassay package insert. Dublin, Ireland: Biotrin International; 2003.
  22. ↵
    Parvovirus B19 IgM enzyme immunoassay package insert. Dublin, Ireland: Biotrin International; 2003.
  23. ↵
    1. Butchko A
    . Comparison of three commercially available serologic assays used to detect human parvovirus B19-specific immunoglobulin M (IgM) and IgG antibodies in sera of pregnant women. J Clin Microbiol 2004;42:3191-5.
    Abstract/FREE Full Text
  24. ↵
    1. Stoltzfus RJ,
    2. Chwaya HM,
    3. Montresor A,
    4. Albonico M,
    5. Savioli L
    . Malaria, hookworms and recent fever are related to anemia and iron status indicators in 0- to 5-y old Zanzibari children and these relationships change with age. J Nutr 2000;130:1724-33.
    Abstract/FREE Full Text
  25. ↵
    1. Young GP,
    2. Smith MB,
    3. Woodfield DG
    . Glucose-6-phosphate dehydrogenase deficiency in Papua New Guinea using a simple methylene blue reduction test. Med J Australia 1974;1:876-8.
    Medline
  26. ↵
    1. Muller I,
    2. Bockarie M,
    3. Alpers M,
    4. Smith T
    . The epidemiology of malaria in Papua New Guinea. Trends Parasitol 2003;19:253-9.
    CrossRefMedlineWeb of Science
  27. ↵
    1. Candotti D,
    2. Etiz N,
    3. Parsyan A,
    4. Allain JP
    . Identification and characterization of persistent human erythrovirus infection in blood donor samples. J Virol 2004;78:12169-78.
    Abstract/FREE Full Text
  28. ↵
    1. Hoebe CJ,
    2. Claas EC,
    3. Steenbergen JE,
    4. Kroes AC
    . Confirmation of an outbreak of parvovirus B19 in a primary school using IgM ELISA and PCR on thumb prick blood samples. J Clin Virol 2002;25:303-7.
    CrossRefMedlineWeb of Science
  29. ↵
    1. Mallouh AA,
    2. Qudah A
    . An epidemic of aplastic crisis caused by human parvovirus B19. Pediatr Infect Dis J 1995;14:31-4.
    MedlineWeb of Science
  30. ↵
    1. Oliveira SA,
    2. Camacho LA,
    3. Pereira AC,
    4. Faillace TF,
    5. Setubal S
    . Clinical and epidemiological aspects of human parvovirus B19 infection in an urban area in Brazil (Niteroi city area, State of Rio de Janeiro, Brazil). Mem Inst Oswaldo Cruz 2002;97:965-70.
    MedlineWeb of Science
  31. ↵
    1. Heegaard ED,
    2. Brown KE
    . Human parvovirus B19. Clin Microbiol Rev 2002;15:485-505.
    Abstract/FREE Full Text
  32. ↵
    1. McElroy PD,
    2. ter Kuile FO,
    3. Lal AA,
    4. et al
    . Effect of Plasmodium falciparum parasitemia density on hemoglobin concentrations among full-term, normal birth weight children in western Kenya, IV. The Asembo Bay Cohort Project. Am J Trop Med Hyg 2000;62:504-12.
    Abstract
  33. ↵
    1. Price RN,
    2. Simpson JA,
    3. Nosten F,
    4. et al
    . Factors contributing to anemia after uncomplicated falciparum malaria. Am J Trop Med Hyg 2001;65:614-22.
    Abstract
  34. ↵
    1. Shaffer N,
    2. Hedberg K,
    3. Davachi F,
    4. et al
    . Trends and risk factors for HIV-1 seropositivity among outpatient children, Kinshasa, Zaire. AIDS 1990;4:1231-6.
    MedlineWeb of Science
  35. ↵
    1. Breman JG
    . The ears of the hippopotamus: manifestations, determinants, and estimates of the malaria burden. Am J Trop Med Hyg 2001;64:1-11.
    Abstract/FREE Full Text
  36. ↵
    1. Ballou WR,
    2. Reed JL,
    3. Noble W,
    4. Young NS,
    5. Koenig S
    . Safety and immunogenicity of a recombinant parvovirus B19 vaccine formulated with MF59C.1. J Infect Dis 2003;187:675-8.
    Abstract/FREE Full Text
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  1. J Infect Dis. (2006) 194 (2): 146-153. doi: 10.1086/505082
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