COCIRCULATION OF MULTIPLE HANTAVIRUSES IN TEXAS, WITH CHARACTERIZATION OF THE SMALL (S) GENOME OF A PREVIOUSLY UNDESCRIBED VIRUS OF COTTON RATS (SIGMODON HISPIDUS)

An environmental and laboratory investigation was conducted after a fa tal childhood case of hantavirus pulmonary syndrome occurred in Deaf S mith County, Texas in May 1995. A trapping campaign was conducted to i dentify possible rodent carriers. Six species of murid and heteromyid rodents were collected, and at least one hantavirus-seropositive speci men was found in each of the five murid species. Tissues from a select ion of 11 seropositive specimens were examined by the polymerase chain reaction (PCR) and sequencing of viral genetic material. The predomin ant hantavirus was El Moro Canyon virus (ELMCV), which occurred in thr ee of three harvest mice (Reithrodontomys megalotis) and in three of f our deer mice (Peromyscus maniculatus) examined. Sin Nombre virus (SNV ) was found in one deer mouse and one white-footed mouse (P. leucopus) . A seropositive house mouse (Mus musculus) was negative by PCR. Two c otton rats (Sigmodon hispidus) were infected by a virus of novel genot ype (Muleshoe virus [MULEV]) that bears closest resemblance to Bayou h antavirus. The sequence of the complete small genomic segment was dete rmined for one MULEV, and high-level expression of its nucleocapsid pr otein was induced in Escherichia coli. Serologic studies indicated tha t the most likely etiologic agent in the human infection was SNV.