Hantavirus Infection in Rattus tanezumi in Rural and Peri-urban Habitats in Luzon, Philippines

CAVIA, REGINO; PIRES-MARCZESKI F; SINGLETON, GRANT; PADULA, PAULA

Beigin

Congreso; X International Conference on HFRS, HPS & Hantavirus; 2013

Fieldwork was conducted in Nueva Ecija, Central Luzon, Philippines, in order to assess the presence of hantavirus and the seroprevalence of infection in rodentss that may be a risk to smallholder farmers in rural rice fields and peri-urban habitats. Rodents were collected in October and November of 2011. Trapping and processing were performed according to established safety recommendations. Species identification was done in the field. A total of 164 Rattus tanesumi, one R. norvegicus and one R. exulants were caught. Serum samples dilutions were tested by an indirect IgG enzyme linked immunosorbent assay (ELISA), using a N recombinant protein of SEOV produced in E. coli and a negative control (a protein extract of E. coli, not containing the plasmid encoding the recombinant protein). Total RNA was extracted from kidney tissues of seropositive rodents. Reverse transcription (RT) procedure and hemi-nested polymerase chain reaction (PCR) were performed to amplify a partial fragment from hantavirus genome. The partial M segment sequence of hantavirus genome was recovered using primers designed to amplify the Gn fragment of 437 nt (6 to 442 related to the SEOV Sapporo strain). The PCR products were purified and sequenced. Multiple nucleotide and amino sequence alignments were done using MEGA 5. IgG antibodies were detected in 11 of 166 serum samples analyzed, all of them corresponded to R. tanesumi (two juveniles and seven  males). All seropositive rodents had low or moderate antibody titers. The viral genome was detected in 4 of 11 seropositive animals, all were males. A comparison of the 418 nt generated from the Gn-M segment with those of other representative SEOV showed the highest nucleotide identity (86.6%) with Serang virus strain Jurong TJK/06 from Singapore, with an amino acid identity of 94 %. This hantavirus strain forms a distinct phylogroup with the Serang, Cambodian and Thailand virus.