Snakebites caused by Crotalus genus are the second most frequent in Brazil. Crotoxin is a beta-neurotoxin responsible for the main envenomation effects of Crotalus biting, while crotamine immobilizes the animal hind limbs, contributing to prey immobilization and to envenoming symptoms. As crotoxin and crotamine represent about 90% of Crotalus venom dry weight, these toxins are of great importance for antivenom therapy. In this sense, knowledge regarding the antigenicity/immunogenicity at the molecular level of these toxins can provide valuable information for the improvement of specific antivenoms. Therefore, the aims of this study are the identification of the B-cell epitopes from crotoxin and crotamine; and the characterization of the neutralizing potency of antibodies directed against the corresponding synthetic epitopes defined in the current study. Linear B-cell epitopes were identified using the Spot Synthesis technique probed with specific anti -C. d. terrificus venom horse IgG. One epitope of crotamine (F(12)PKEKICLPPSSDFGKMDCRW(32)) and three of crotoxin (L(10)LVGVEGHLLQFNKMIKFETR(30); Y(43)CGWGGRGRPKDATDRCCFVH(63) and T(118)YKYGYMFYPDSRCRGPSETC(138)) were identified. After synthesis in their soluble form, the peptides mixture correspondent to the mapped epitopes was entrapped in liposomes and used as immunogens for antibody production in rabbits. Anti-synthetic peptide antibodies were able to protect mice from the lethal activity of C. d. terrificus venom. (C) 2020 Elsevier B.V. All rights reserved.

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 >99.5% homology between SEOV sequences in this outbreak, and these were >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.