Hi.
What is the status of your parvovirus infection? The B19 parvovirus is the human pathogen. Other types mainly affect animals (dogs, cats). In the first phase of B19 infection, the white blood cell count may decrease, along with a decrease in platelet count. This first phase usually lasts for about a week, which is not compatible with your temporal profile (you had the infection in January 2008). I have not come across metoprolol and aspirin causing decrease in white blood cell count. There may be other cause/s for the decrease in your white blood cell count. Perhaps a peripheral blood smear can be done to check the morphology of the cells. A bone marrow biopsy can also be done to see if the marrow is not producing enough precursors.
Regads.