الفهرس 
Chapter1: Parvovirus B19Only 14 pages are availabe for public view
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Abstract
Human parvovirus B19 is a small non-enveloped DNA virus belonging to the genus Erythrovirus (family Parvoviridae). Although, it generally causes self-limiting conditions in healthy people, B19V infections may have a different outcome in patients with inherited hemolytic anemia. In such high-risk individuals, the high-titer replication may result in bone marrow suppression, triggering a life threatening DROP of hemoglobin values (profound anemia, aplastic crisis).There is avicious circle between parvovirus B19 infections and occurance of aplastic crisis. The present study was conducted in Microbiology and Immunology Department, Faculty of Medicine, Menoufia University.The objective of this study was to determine the prevalence of human parvovirus B19 infection in children with a variety of hematological disorders and in healthy children through the detection of parvovirus B19 IgG antibodies in their sera.Forty children with chronic hemolytic anemia without a history of aplastic crisis (group I), twenty children with chronic hemolytic anemia with a history of aplastic crisis (group II) and twenty apparently healthy children (group III) were selected from Pediatrics Department in Menoufia University Hospitals.Clinical examinations and laboratory investigations (CBC, serum ferretin and Hb electrophoresis) were done to all the patients and control groups,then detection of parvovirus B19 IgG antibodies in the sera of all the studied groups by using anti-parvovirus B19 ELISA kit (EUROIMMUN).The present study found that; males with chronic hemolytic anemia without history of aplastic crisis (60%) and with a history of aplastic crisis (70%) were more than in females in both groups. The highest mean age was found in chronic anemia patients with a history of aplastic crisis 11.95 ±3.02. In the present study, children with splenectomy were (52.5 % in group I and 85% in group II) more than those with splenomegaly in both groups.According to the current study, the prevalence of anti-parvovirus B19 IgG in children with chronic hemolytic anemia without history of aplastic crisis was 62.5% and the prevelance in children with chronic hemolytic anemia with a history of aplastic crisis was 100%. 20% in apparently healthy children in this study had anti-parvovirus B19 IgG antibodies. In the present study, 50 patients out of 60 (83.3%) in all chronic hemolytic anemia patients with or without aplastic crisis were categorized as β-thalassemia major. 39 patients out of 50 β-thalassemia major patients (78%) had detectable level of anti-parvovirus B19 virus IgG antibodies.There was statistical significant difference between thalassemia major among group I and II regarding anti-parvovirus B19 IgG, were seropositivity in thalassemia major among group I and group II were 68.6% and 100% respectively. In the present study; there was significant positive correlation between the age of all children with chronic hemolytic anemia with or without aplastic crisis and the level of anti-parvovirus B19 IgG (r=0.424) (P value = 0.001). Also, there was a significant positive correlation between frequency of blood transfusion and the prevalence of anti-parvovirus B19 IgG. The results obtained in this study revealed that there was a marked decreasing in mean of hemoglobin of positive anti-parvovirus B19 IgG children with chronic hemolytic anemia with or without ahistory of aplastic crisis. On contrary, there were leukocytosis and thrombocytosis among IgG sero-positive children than in IgG sero-negative in chronic hemolytic anemia but without significant difference. In this study, 25% of chronic hemolytic anemia children with aplastic crisis were diagnosed as sickle cell anemia and all of them (100%) had anti-parvovirus B19 IgG.