Seoul Virus Infection and Spread in United States Home-Based Ratteries: Rat and Human Testing Results From a Multistate Outbreak Investigation
Authors: Knust Barbara , Brown Shelley , de St. Maurice Annabelle , Whitmer Shannon , Koske Sarah E , Ervin Elizabeth , Patel Ketan , Graziano James , Morales-Betoulle Maria E , House Jennifer , Cannon Deborah , Kerins Janna , Holzbauer Stacy , Austin Connie , Gibbons-Burgener Suzanne , Colton Leah , Dunn John , Zufan Sara , Choi Mary Joung , Davis William R , Chiang Cheng-Feng , Manning Craig R , Roesch Linda , Shoemaker Trevor , Purpura Lawrence , McQuiston Jennifer , Peterson Dallin , Radcliffe Rachel , Garvey Ann , Christel Ellen , Morgan Laura , Scheftel Joni , Kazmierczak James , Klena John D , Nichol Stuart T , Rollin Pierre E ,   the Multistate Seoul Virus Outbreak Investigation Team, Jones Dee , Weinstein Susan , Buck Peter , Barton Behravesh Casey , Genzer Sarah , Jackson Eddie , M. Harley Jenks , Langham Gregory , Lathrop George , Patel Nishi , Powell Nathaniel , Straily Anne , Ströher Ute , Marzec Natalie , Luong Nhiem , Stanek Danielle , Gabel Julie , Carter Kris , Lovejoy Jodi , Brown Jennifer , Schroeder Betsy , Layden Jennifer , Balsamo Gary , Blythe David , Castillo Caroline , Sidge Jennifer , Grace Stobierski Mary , Hall Victoria , Ireland Malia , Signs Kimberly , Pue Howard , Campbell Colin , Baber Jill , Cronquist Laura , Feist Michelle , Keller Susan , Singh Amber , Gowdy Karen , Middleton Dean , Achenbach Jan , D. Dycus Drew , Smee Aaron , Weltman Andre , Margaret Fill Mary , Henderson Heather , Jones Timothy , Stephen May Andrew , Mullins Heather , Sidwa Tom , Nakashima Allyn , Foelker Dennis , Dieckman Jordan , F. Klos Rachel , Kocharian Anna 
Published: May 2020

Background

During 2017, a multistate outbreak investigation occurred after the confirmation of Seoul virus (SEOV) infections in people and pet rats. A total of 147 humans and 897 rats were tested.

Methods

In addition to immunoglobulin (Ig)G and IgM serology and traditional reverse-transcription polymerase chain reaction (RT-PCR), novel quantitative RT-PCR primers/probe were developed, and whole genome sequencing was performed.

Results

Seventeen people had SEOV IgM, indicating recent infection; 7 reported symptoms and 3 were hospitalized. All patients recovered. Thirty-one facilities in 11 US states had SEOV infection, and among those with ≥10 rats tested, rat IgG prevalence ranged 2%–70% and SEOV RT-PCR positivity ranged 0%–70%. Human laboratory-confirmed cases were significantly associated with rat IgG positivity and RT-PCR positivity (P = .03 and P = .006, respectively). Genomic sequencing identified &gt;99.5% homology between SEOV sequences in this outbreak, and these were &gt;99% identical to SEOV associated with previous pet rat infections in England, the Netherlands, and France. Frequent trade of rats between home-based ratteries contributed to transmission of SEOV between facilities.

Conclusions

Pet rat owners, breeders, and the healthcare and public health community should be aware and take steps to prevent SEOV transmission in pet rats and to humans. Biosecurity measures and diagnostic testing can prevent further infections.