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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 30  |  Issue : 1  |  Page : 255-261

Seroprevalence of human parvovirus B19 immunoglobulin G in children with hematological disorders and healthy children


1 Department of Medical Microbiology and Immunology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Ophthalmology Hospital, Shebin El-Kom, Menoufia, Egypt

Date of Submission08-Feb-2016
Date of Acceptance13-Apr-2016
Date of Web Publication25-Jul-2017

Correspondence Address:
Seham A El Shorbagy Eissa
Shebin El-Kom, Menoufia, 32511
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mmj.mmj_74_16

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  Abstract 


Objective
The aim of this study was to determine the serum levels of anti-parvovirus B19 immunoglobulin-G (IgG) and its prevalence in children with hematological disorders and in apparently healthy children in Menoufia University Hospitals.
Background
Parvovirus B19 infections can suppress erythropoiesis and induce acute erythroblastopenia, which is often referred to as transient aplastic crisis in patients with chronic hemolytic anemia such as sickle cell anemia, thalassemia, and hereditary spherocytosis.
Patients and methods
The study was conducted on 60 children with chronic hemolytic anemia (40 children with chronic hemolytic anemia without a history of aplastic crisis and 20 children with chronic hemolytic anemia with a history of aplastic crisis) and 20 age-matched and sex-matched apparently healthy children. All patients were subjected to full history taking, clinical examination, and laboratory investigations. Serum anti-parvovirus B19 IgG levels were measured using anti-parvovirus B19 ELISA kits.
Results
The prevalence of anti-parvovirus B19 IgG antibodies in the sera of chronic hemolytic anemia children with and without a history of aplastic crisis was 62.5 and 100%, respectively. Seropositivity of anti-parvovirus B19 IgG antibodies was 20% in apparently healthy children. Seropositivity of anti-parvovirus B19 IgG antibodies in children with β-thalassemia major and sickle cell anemia was 78 and 100%, respectively. Significant positive correlations were detected between age of the children, frequency of blood transfusion, and the level of anti-parvovirus B19 IgG.
Conclusion
The prevalence of anti-parvovirus B19 IgG antibodies was higher in all chronic hemolytic anemia children, particularly in those with a history of aplastic crisis. Furthermore, all children with β-thalassemia major and sickle cell anemia with a history of aplastic crisis had anti-parvovirus B19 IgG antibodies.

Keywords: chronic hemolytic anemia, parvovirus B19 immunoglobulin-G, transient aplastic crisis


How to cite this article:
Makled AF, Aly Salama AA, Elhawy MA, El Shorbagy Eissa SA. Seroprevalence of human parvovirus B19 immunoglobulin G in children with hematological disorders and healthy children. Menoufia Med J 2017;30:255-61

How to cite this URL:
Makled AF, Aly Salama AA, Elhawy MA, El Shorbagy Eissa SA. Seroprevalence of human parvovirus B19 immunoglobulin G in children with hematological disorders and healthy children. Menoufia Med J [serial online] 2017 [cited 2019 Apr 18];30:255-61. Available from: http://www.mmj.eg.net/text.asp?2017/30/1/255/211529




  Introduction Top


Human parvovirus B19 is a small single-stranded, nonenveloped DNA virus belonging to the genus Erythrovirus [1]. Parvovirus B19 can replicate primarily in erythroblasts in the bone marrow through high molecular weight intermediate linked through hairpin structures because of the presence of genomic palindromes [2]. Parvovirus B19 infections have been reported as a nosocomial infection with transmission through blood products (especially pooled factors VIII and IX) and in healthcare workers from patients and contaminated specimens [3].

Infections with parvovirus B19 are common, particularly in children in whom the pattern of its clinical diseases is influenced by both hematological and immunological status of the infected individuals. In healthy hosts, parvovirus B19 virus causes self-limiting asymptomatic erythroid aplasia [1], followed by erythema infectiosum (slapped-cheek syndrome or the fifth disease), arthritis, leukopenia, vasculitis, spontaneous thrombocytopenia, anemia, abortion, and hydropsfetalis in pregnant women [2]. However, in patients with hematological disorders, especially chronic hemolytic anemia such as sickle cell anemia, thalassemia, and hereditary spherocytosis, erythroid progenitor cell formation is increased to compensate for red blood cell lysis, and B19 virus infections can suppress erythropoiesis and induce acute erythroblastopenia, which is often referred to as transient aplastic crisis [4].

The transmission of parvovirus B19 occurs through respiratory droplets, contaminated blood, organ transplantation, and vertical transmission from mother to fetus. The small size of parvovirus B19 makes its removal by means of filtration with virus-removal membranes impossible [5]. The prevalence of immunity to parvovirus B19, indicative of prior infection, has been shown to rise with age. This prevalence was demonstrated to rise from ~40% in children and adolescents, to 60% in adults, to 75% in adults older than 40 years [6].

Hemolytic anemia is a type of anemia that refers to a condition in which the blood has a lower than normal number of red blood cells [7]. Thalassemia is a hereditary anemia resulting from genetic disorders of hemoglobin synthesis [8].

Children with chronic hemolytic anemia usually are on a hypertransfusion regimen and hence are at high risk of acquiring transfusion-transmitted parvovirus B19. A sudden worsening of anemia, reticulocytopenia, and cessation of erythropoiesis in the bone marrow characterize the transient aplastic crisis. It is possible that parvovirus B19-induced aplastic crisis may often be wrongly diagnosed as a complication of the underlying disease [9].


  Patients and Methods Top


The protocol was approved by the ethical committee in Menoufia university. An informed written consent was obtained all the participants.

Study population and selection of patients

This study was conducted at the Microbiology and Immunology Department, Faculty of Medicine, Menoufia University, in collaboration with the Pediatric Department, Faculty of Medicine, Menoufia University, during the period from November 2014 to June 2015. It involved three groups: group I included 40 children with chronic hemolytic anemia without a history of aplastic crisis, group II included 20 children with chronic hemolytic anemia with a history of aplastic crisis, and group III included 20 age-matched and sex-matched apparently healthy children.

Inclusion criteria were as follows: age between 1 and 15 years; clinically diagnosed chronic hemolytic anemia, documented by hemoglobin electrophoresis; and previously received blood transfusion.

Permission of the patients' parents and approval from the local ethics committee were obtained for the use of the specimens.

The patients were subjected to the following:

  1. History taking including history of present illness such as pallor and jaundice, blood transfusion, and drug intake and past history of first blood transfusion and frequency of blood transfusion
  2. Clinical examination (abdominal examination to detect hepatosplenomegaly, scar of splenectomy, and any septic focus or acute inflammatory disease) and anthropometric measurements
  3. Laboratory investigations:

    1. Complete blood count using AC 920 auto counter (Becton Dickinson, Meyland Cedex, France) to estimate hemoglobin level and blood parameters [mean corpuscular volume (MCV), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width (RDW), white blood cells (WBCs), and platelets]
    2. Hemoglobin electrophoresis.


Collection of blood samples

About 5 ml of venous blood was aseptically drawn from all studied groups and centrifuged at ~1000g for 15 min to separate the serum, which was stored at −20°C. Repeated freeze–thaw cycles were avoided.

Quantification of the serum levels of anti-parvovirus B19 immunoglobulin-G antibodies

The serum levels of anti-parvovirus B19 immunoglobulin-G (IgG) antibodies were quantified using Euroimmun human anti-parvovirus B19 IgG ELISA kits according to the manufacturer's instructions (Euroimmun, Lübeck, Germany). Euroimmun ELISA kits provided a quantitative in-vitro assay for human anti-parvovirus B19 IgG antibodies in serum. The test kit contained microtiter strips, each with eight break-off reagent wells coated with parvovirus antigens. In the first reaction step, diluted patient samples were incubated in the wells. In the case of positive samples, specific IgG antibodies bound to the antigens. To detect the bound antibodies, a second incubation was carried out using enzyme conjugate catalyzing a color reaction. 'Point-to-point' plotting was used for the calculation of the standard curve using computer.

Statistical analysis

The data collected were tabulated and analyzed using statistical (SPSS Inc., Chicago, Il, USA) package for the social sciences, version 22.0 on IBM compatible computer. Two types of statistics were performed: descriptive statistics (e.g., percentage, mean and SD) and analytic statistics [e.g., χ2-test, Fisher's exact test, Student's t-test, Mann–Whitney test, analysis of variance (F) test, Kruskal–Wallis test, and post-hoc test]. A P value less than 0.05 was considered to be significant.

Spearman's correlation coefficient (r) was used to measure the association between two quantitative variables not normally distributed.


  Results Top


This study included two patient groups: group I, which included 40 children with chronic hemolytic anemia without a history of aplastic crisis (87.5% with β-thalassemia major, 10% with thalassemia intermedia, and 2.5% with hereditary spherocytosis), and group II, which included 20 children with chronic hemolytic anemia with a history of aplastic crisis (75% with β-thalassemia major and 25% with sickle cell anemia), as shown in [Figure 1]. Highly statistically significant differences were detected between group I and controls and group II and controls with P value less than 0.001 as regards status of the spleen, as shown in [Table 1].
Table 1 Demographic and clinical data of studied groups

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Figure 1: Types of chronic hemolytic anemia in group I and group II.

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Anti-parvovirus B19 IgG antibodies were detected in 62.5 and 100% of patients in group I and group II, respectively. Only 20% in the control group had a detectable level of anti-parvovirus B19 IgG. There were statistically significant differences between group I and group II and group I and controls, and there was a highly statistically significant difference between group II and controls as regards the prevalence of anti-parvovirus B19 IgG, as shown in [Table 2].
Table 2 Prevalence and values of anti-parvovirus B19 immunoglobulin-G among the studied groups

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There was a significant positive correlation between age of the patients in both groups and the level of anti-parvovirus B19 IgG. Moreover, there was a significant positive correlation between frequency of transfusion and level of anti-parvovirus B19 IgG, as shown in [Table 3].
Table 3 Spearman correlation between level of anti-parvovirus B19 immunoglobulin-G and age, age of start blood transfusion, frequency of transfusion, and different complete blood count parameters among cases (groups I and II)

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A highly statistically significant difference was detected in positive anti-parvovirus B19 IgG among patient groups and controls as regards hemoglobin. There were statistically significant differences in positive anti-parvovirus B19 IgG between group II and controls as regards MCV, red cell distribution width, WBCs, and platelets, as shown in [Table 4].
Table 4 Comparison between positive anti-parvovirus B19 immunoglobulin-G among three groups as regards different complete blood count parameters

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Totally, 39 children with β-thalassemia major out of 50 (78%) had detectable levels of anti-parvovirus B19 IgG. Seropositivity of parvovirus B19 IgG antibody in children with β-thalassemia major in group I and group II was 68.6 and 100%, respectively, with a statistically significant difference, as shown in [Figure 2]. Anti-parvovirus B19 IgG antibodies were detected in 25% of children with thalassemia intermedia. Moreover, anti-parvovirus B19 IgG antibodies were detected in all children with sickle cell anemia (100%). There were statistically significant differences between β-thalassemia major and thalassemia intermedia, thalassemia intermedia and sickle cell anemia, and hereditary spherocytosis and sickle cell anemia as regards the prevalence of anti-parvovirus B19 IgG, as shown in [Table 5].
Figure 2: Comparison between thalassemia major in group I and group II as regards anti-parvovirus B19 immunoglobulin-G.

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Table 5 Prevalence of anti-parvovirus B19 immunoglobulin-G among different types of anemia

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  Discussion Top


Human parvovirus B19 is a small nonenveloped DNA virus belonging to the genus Erythrovirus (family Parvoviridae). Although it generally causes self-limiting conditions in healthy people, B19V infection may have a different outcome in patients with inherited hemolytic anemias [1].

The present study found that the percentage of male patients with chronic hemolytic anemia without history of aplastic crisis (60%) and with a history of aplastic crisis (70%) was higher compared with the percentage of female patients in both groups. This is in agreement with the results reported by Palit et al. [10] in Bangladesh.

In the present study, the highest mean age was found in chronic anemia patients with a history of aplastic crisis (11.95 ± 3.02), as the incidence of aplastic crisis increases with age [11]. Bukar et al. [12] found that aplastic crisis increases the need for blood transfusion.

In the present study, the proportion of children with splenectomy was higher than those with splenomegaly in patient groups. This result is in accordance with that reported by Porecha et al. [13] in India. In chronic hemolytic anemia, the patient's hemoglobin levels may drop causing the body to try to create more red blood cells in the bone marrow and some other organs such as spleen (extramedullary erythropoiesis) leading to hypersplenism, which is enlarged and hyperactive spleen; it is one of the major indications of splenectomy [13].

In the present study, there was a significant increase in MCV in children with chronic hemolytic anemia with aplastic crisis. This result is in accordance with that of Mallouh [14], who found the occurrence of macrocytosis (large red blood cells) in patients with aplastic crisis.

According to the current study, the prevalence of anti-parvovirus B19 IgG in children with chronic hemolytic anemia without a history of aplastic crisis was 62.5%. This finding is similar to that reported by many authors such as Azzazy et al. [15] in Egypt, Badr [16]in Saudi Arabia, and Regaya et al. [17] in Tunis, who demonstrated that the prevalence of anti-parvovirus B19 IgG in this group of patients was 52, 56.5, and 61%, respectively.

In the present study, the prevalence of anti-parvovirus B19 IgG in children with chronic hemolytic anemia with a history of aplastic crisis was 100%. Zaki et al. [18] and Azzazy et al. [15] found that parvovirus B19 IgG positivity was lower (50 and 34%, respectively). The high prevalence in the present study may due to the presence of transient aplastic crisis caused by parvovirus B19 IgG [12].

The present study showed that the prevalence of anti-parvovirus B19 IgG antibodies in apparently healthy children was 20%. A similar result was observed by Kishore [9], who found that IgG positivity in the control group was 21%. High prevalence of anti-parvovirus B19 IgG antibodies in the control group was reported by Obeid [4], in Saudi Arabia (39%), Azzazy et al. [15] in Egypt (40%), and Musa [19] in Nigeria (42%). This difference may be attributed to the fact that the mean age of apparently healthy children in this study was younger than the mean age in apparently healthy children in the previous studies. Green and Fraire [20]found that the prevalence of anti-parvovirus B19 IgG increases with age.

In the present study, there was a significant positive correlation between the age of all patients with chronic hemolytic anemia and the level of anti-parvovirus B19 IgG (r = 0.424) (P = 0.001). This result is in agreement with those reported by Cennimo [21]in New Jersey, Eidand Chen [22], and Green and Fraire [20], who found that seropositivity rates were 5–10% among young children (age: 2–5 years), increasing to 50% by the age of 15 years. In contrast to the present study, Obeid [4], in Saudi Arabia, Kishore et al. [9] in India, andMusa et al. [19]in Nigeria found that there was no correlation between viral-specific antibody positivity and age.

Increased seropositive rates of parvovirus infections associated with blood transfusion were reported in Taiwan and Hong Kong [1]. This observation was supported by the data in the present study, as there was a significant positive correlation between frequency of blood transfusion and prevalence of anti-B19 virus IgG. This is in agreement with the result of Kishore et al. [9] in India, who found that the seropositivity of anti-B19 virus IgG increased with an increase in the number of blood transfusions, as the transfused anemic patients may receive packed red cells containing parvovirus B19. However, Siritantikorn et al. [23] in Thailand found that the prevalence of anti-parvovirus B19 IgG in multitransfused thalassemia patients was not higher than that in the nontransfused patients. This might be due to the low prevalence of parvovirus B19 infection in the blood donor group.

In the present study, there was marked decrease in mean hemoglobin in positive anti-parvovirus B19 IgG children with chronic hemolytic anemia. This result is in agreement with that noticed by Zaki et al. [18], Cennimo [21], and Azzazy et al. [15], who reported a decrease in hemoglobin levels of 2–6 g/dl in chronic hemolytic anemia patients with positive anti-parvovirus B19 IgG. However, Bukar et al. [12]in Nigeria found that there was no strong association between the hematologic parameters and parvovirus B19 seropositivity.

The present study revealed a higher mean total leukocyte count among IgG seropositive children than among IgG seronegative children with chronic hemolytic anemia, but this difference was not statistically significant. This result is in agreement with that reported by Girei et al. [24]and Bukar et al. [12], who found an increase in WBC count with anti-B19 IgG seropositivity in chronic hemolytic anemia patients due to multiple bacterial infections, which is associated with repeated blood transfusions.

The present study found an increase in the mean of platelets in positive anti-parvovirus B19 IgG patients with chronic hemolytic anemia. However, Zaki et al. [18], Cennimo [21], Azzazy et al. [15], and Bukar et al. [12] reported that thrombocytopenia is considered as a constant feature in patients with hematologic disorders who were recently infected with parvovirus B19. This difference can be attributed to the presence of bone marrow compensation (medullary and extramedullary hematopoiesis) leading to thrombocytosis [25].

In the present study, 50 of 60 (83.3%) chronic hemolytic anemia children were categorized as β-thalassemia major. Totally, 39 children of 50 (78%) β-thalassemia major patients had a detectable level of anti-parvovirus B19 virus IgG antibodies. This result is in agreement with the findings of Lee et al. [26] in Taiwan and Kishore et al. [9] in India, who reported that 81 and 71.9%, respectively, of β-thalassemia major patients were positive for anti-parvovirus B19 virus IgG antibodies. Multitransfused β-thalassemia major patients are the most susceptible population to acquire transfusion-related infections, including B19 virus [27].

In the present study, patients with sickle cell anemia who presented with chronic hemolytic anemia with aplastic crisis constituted only 25% (five patients) and all of them had anti-parvovirus B19 IgG. This result could be attributed to the fact that sickle cell anemia children in the present study had a history of aplastic crisis. There is a vicious circle; parvovirus B19 causes aplastic crisis, which in turn causes increased transfusion need, and blood transfusion increases the risk for transfusion transmissible infection in which parvovirus B19 is included [12]. Moreover, Cennimo [21] found that parvovirus B19 was the only infectious cause of transient aplastic crisis known and has been shown to be the cause of aplastic crisis in over 80% of patients with sickle cell disease.


  Conclusion Top


From this study we can conclude that the prevalence of anti-parvovirus B19 IgG antibodies was higher in all chronic hemolytic anemia children, particularly in those with a history of aplastic crisis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Slavov SN, Kashima S, Pinto AC, Covas DT. Human parvovirus B19: general considerations and impact on patients with sickle-cell disease and thalassemia and on blood transfusions. FEMS Immunol Med Microbiol 2011; 62:247–262.  Back to cited text no. 1
    
2.
Kerr JR. A review of blood diseases and cytopenias associated with human parvovirus B19 infection. Rev Med Virol 2015; 25:224–240.  Back to cited text no. 2
    
3.
Kooistra K, Mesman HJ, de Waal M, Koppelman MH, Zaaijer HL. Epidemiology of high-level parvovirus B19 viraemia among Dutch blood donors, 2003 2009. Vox Sang 2011; 100:261–266.  Back to cited text no. 3
    
4.
Obeid OE. Molecular and serological assessment of parvovirus B19 infections among sickle cell anemia patients. J Infect Dev Ctries 2011; 5:535–539.  Back to cited text no. 4
    
5.
Yunoki M, Urayama T, Tsujikawa M, Sasaki Y, Abe S, Takechi K, Ikuta K. Inactivation of B19 by liquid heating incorporated in the manufacturing process of human intravenous immunoglobulin preparations. Br J Haematol 2005; 128:401–404.  Back to cited text no. 5
    
6.
Kelly HA, Siebert D, Hammond R, Leydon J, Kiely P, Maskill W. The age specific prevalence of human parvovirus immunity in Victoria, Australia compared with other parts of the world. Epidemiol Infect 2000; 124:449–457.  Back to cited text no. 6
    
7.
El-Beshlawy A, Kaddah N, Moustafa A, Mouktar G, Youssry I. Screening for ß-thalassemia carriers in Egypt: significance of the osmotic fragility test. East Mediterr Health J 2007; 13:780–786.  Back to cited text no. 7
    
8.
Ragab SM, Safan MA, Asmaa S Sherif: lipid profiles in β-thalassemic children. Menoufia Med J 2014; 27:66–72.  Back to cited text no. 8
    
9.
Kishore J, Srivastava M, Choudhury N. Serological study on parvovirus B19 infection in multitransfused thalassemia major patients and its transmission through donor units. Asian J Transfus Sci 2011; 5:140–143.  Back to cited text no. 9
[PUBMED]  [Full text]  
10.
Palit S, Bhuiyan RH, Aklima J, Emran TB, Dash R. A study of the prevalence of thalassemia and its correlation with liver function test in different age and sex group in the Chittagong district of Bangladesh. J Basic Clin Pharm 2012; 3:352–357.  Back to cited text no. 10
    
11.
Borsato ML, Bruniera P, Cusato MP, Spewien KE, Durigon EL, Toporovski J. Aplastic crisis in sickle cell anemia induced by parvovírus B19. J Pediatr (Rio J). 2000; 76:458–460.  Back to cited text no. 11
    
12.
Bukar AA, Abjah UAM, Kagu AI, Ladu MB, Zailani SB, Abba AM, Malah MB, et al. Seroprevalence of parvovirus B19 and its clinical effect among anaemic SCA patients in Northeastern Nigeria. Am J Sci Ind Res 2013; 4:195–200.  Back to cited text no. 12
    
13.
Pecorari L, Savelli A, Guna CD, Fracchia S, Borgna-Pignatti C. The role of splenectomy in thalassemia major. An update. Acta Pediatrica Mediterranea 2008; 24:57–60.  Back to cited text no. 13
    
14.
Mallouh AA. Practical approach to anemia in children. Abdelaziz YE, editor. Textbook of clinical pediatrics. Berlin Heidelberg; Springer-Verlag; 2012. p. 113–121. DOI 10.1007/978-3-642-02202-9_316.  Back to cited text no. 14
    
15.
Azzazy EA, Shaheen AA, Mousaad AA, Abdel Salam MM, Ibrahim RA. The prevalence of human parvovirus B19 infection in children with a variety of hematological disorders. Egypt J Haematol 2013; 38:115–121.  Back to cited text no. 15
  [Full text]  
16.
Badr MA. Human parvovirus B19 infection among patients with chronic blood disorders. Saudi Med J 2002; 23:295–297.  Back to cited text no. 16
    
17.
Regaya F, Oussaief L, Bejaoui M, Karoui M, Zili M, Khelifa R. Parvovirus B19 infection in Tunisian patients with sickle-cell anemia and acute erythroblastopenia. BMC Infect Dis 2007; 7:123–129.  Back to cited text no. 17
    
18.
Zaki ME, Hassan SA, Seleim T, Lateef RA. Parvovirus B19 infection in children with a variety of hematological disorders. Hematology 2006; 11:261–266.  Back to cited text no. 18
    
19.
Musa, SAU, Banwat EB, Zhakom P, Rumji EM, Yakubu RK, Rufai OA. Risk of transfusion-transmitted human parvovirus B19 infection in Anyigba and Lokoja, Kogi State – Nigeria Iosr. J Pharm 2013; 3:66–70.  Back to cited text no. 19
    
20.
Green LK, Fraire AE. Viruses and the lung. Berlin Heidelberg: Springer-Verlag; 2014.  Back to cited text no. 20
    
21.
Cennimo, DJ. Parvovirus B19 infection. Available at: http://emedicine.medscape.com [Last accessed on 2015 Jul 20].  Back to cited text no. 21
    
22.
Eid AJ, Chen SF. AST infectious diseases community of practice: human parvovirus B19 in solid organ transplantation. Am J Transplant 2013; 13 (Suppl 4):201–205.  Back to cited text no. 22
    
23.
Siritantikorn S, Kaewrawang S, Siritanaratkul N, Theamboonlers A, Poovorawan Y, Kantakamalakul W, Wasi C. The prevalence and persistence of human parvovirus B19 infection in thalassemic patients. Asian Pac J Allergy Immunol 2007; 25:169–174.  Back to cited text no. 23
    
24.
Girei AI, Alao OO, Joseph DE, Damulak DO, Orkuma J, Banwat EB. Haematological profile of sickle cell anaemia in children with human parvovirus B19 infection in Jos, North Central Nigeria. J Clin Med Res 2010; 2:152–155.  Back to cited text no. 24
    
25.
Mantadakis E, Tsalkidis A, Chatzimichael A. Thrombocytosis in childhood. Indian Pediatr 2008; 45:669–677.  Back to cited text no. 25
    
26.
Lee YM, Tsai WH, You JY, Ing-TiauKuo B, Liao PT, Ho CK, Hsu HC. Parvovirus B19 infection in Taiwanese patients with hematological disorders. J Med Virol 2003; 71:605–609.  Back to cited text no. 26
    
27.
Alter HJ, Stramer SL, Dodd RY. Emerging infectious diseases that threaten the blood supply. Semin Hematol 2007; 44:32–41.  Back to cited text no. 27
    


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