A NEW DENSOVIRUS ISOLATED FROM TX. SPLENDENS Vol 38 No. 2 March 2007 283 Correspondence: Dr Sa-nga Pattanakitsakul, Divi- sion of Medical Molecular Biology, 12 th Fl Adulyadej Vikrom Building, Faculty of Medicine Siriraj Hospi- tal, Mahidol University, Prannok Road, Bangkok Noi, Bangkok 10700, Thailand. Tel/Fax: 66 (0) 2418-4793 E-mail: sispn@mahidol.ac.th or sipml@mahidol.ac.th A NEW DENSOVIRUS ISOLATED FROM THE MOSQUITO TOXORHYNCHITES SPLENDENS (WIEDEMANN) (DIPTERA:CULICIDAE) Sa-nga Pattanakitsakul 1,4 , Kobporn Boonnak 1,2 , Kusuma Auethavornanan 1,2 , Aroonroong Jairungsri 1 , Thaneeya Duangjinda 4 , Punjaporn Puttatesk 1 , Supatra Thongrungkiat 3 and Prida Malasit 1,4 1 Division of Medical Molecular Biology, Office for Research and Development, 2 Department of Immunology and Immunology Graduate Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand; 3 Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; 4 Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand Abstract. A new densovirus was isolated and characterized in laboratory strains of Toxorhynchites splendens. The virus was detected by polymerase chain reaction (PCR) from mosquitoes reared in our laboratory. PCR fragments from each mosquito were compared by single strand conformation polymorphism (SSCP) assay and found to be indistinguishable. Thus, it is likely the densoviruses from these mosquitoes contain homologous nucleotide se- quences. The PCR fragment corresponding to a 451 bp densovirus structural gene segment from each of 5 mosquitoes had 100% identical nucleotide sequences. Phylogenetic analysis of the structural gene sequence suggests the newly isolated densovirus is more closely related to Aedes aegypti densovirus ( AaeDNV) than to Aedes albopictus densovirus ( AalDNV). Analy- sis of offspring and predated larvae suggests that vertical and horizontal transmission are responsible for chronic infections in this laboratory strain of Toxorhynchites splendens. The virion DNA is 4.2 kb in size, is closely related to, but distinct from, known densoviruses in the genera Brevidensovirus and Contravirus . The virus is tentatively named Toxorhynchites splendens densovirus ( TsDNV). The GenBank accession number of the sequence reported in this paper is AF395903 INTRODUCTION Densoviruses (DNV) are small non-envel- oped, single-stranded DNA viruses that be- long to the family Parvoviridae (Kurstak, 1972; Bachmann et al, 1975; Tijssen et al, 1976; Siegl et al, 1985). This family is currently sub- divided into two subfamilies, the Parvovirinae and the Densovirinae. Viruses in the former subfamily infect vertebrates while the latter infects invertebrates (mainly insects). All densoviruses have narrow host ranges, infect- ing only closely related insects and causing fatal disease in their host larvae. Within the Densovirinae, three genera are known: Densovirus (infecting cockroaches), Iteravirus (infecting silk worms) and Brevidensovirus or Contravirus (infecting mosquitoes). The mem- bers of the genus Densovirus, Junonia coenia densovirus ( Jc DNV) and Galleria mellonella densovirus ( GmDNV), have a genome size of