OROSCO, FREDMOORE L., Virology and Vaccine Institute of the Philippines Program, Industrial Technology Development Institute, Department of Science and Technology, Bicutan-1634, Taguig City, Philippines. S and T Fellows Program, Department of Science and Technology, Bicutan-1634, Taguig City, Philippines. Department of Biology, College of Arts and Sciences, University of the Philippines Manila, Ermita, Manila, Philippines, Philippines