Charelisse Guevara Reyes
Charelisse Guevara Reyes is a rising senior studying Biology with a minor in Medical Humanities and Health at the University of Puerto Rico RÃo Piedras Campus
Since the 1990s, the avian influenza virus, specifically strain H5N1, has primarily affected wild birds. However, it has recently caused multistate outbreaks in US dairy cattle.
This strain has spread from cows to other mammals, including sporadic transmission to humans and pets. It marks the first observed cow-to-human transmission of H5N1. BSRP 2024 was a transformative, challenging, and life-changing experience. The Scientific Communication course, BLD sessions, Faculty Breakfast, and workshops helped us develop into better versions of ourselves and scientists. Surrounded by a community of passionate and driven individuals, I grew alongside new friends who quickly became like family. Their dedication, enthusiasm for science, love, and support made this experience unique. Working alongside prestigious scientists and learning from incredible mentors broadened my scientific understanding and fueled my aspiration to transform realities and improve society through research. I am deeply grateful for the support and guidance from all the BSRP staff, mentors, and lab members. Lastly, BSRP is about science, leadership, community, and, most importantly, change. I cannot wait to see all the changes we will make in the world and how we will use all the lessons to transform the science community.The close interaction between cattle, their products, and humans increases the risk of a significant outbreak. This study aimed to detect the presence of H5N1 in pasteurized commercial milk to understand if this is a useful surveillance method. We hypothesized the high amount of H5N1 receptors in bovine mammary glands would allow H5N1 to be shed in high concentrations in milk, allowing for easy detection in milk from infected cattle. Over six weeks, we surveyed pasteurized commercial milk samples collected from multiple states using both qPCR and dPCR diagnostic techniques. We used a Taqman PCR assay targeting the HA gene of the H5N1 genome to evaluate the pathogen concentration in the samples and an RNase P EvaGreen assay specific to bovines as a positive extraction process control. We performed an inhibition check of milk samples on H5N1 dPCR and found that concentrated milk showed no evidence of PCR inhibition. We also recovered genomes from 23 H5N1virus–positive milk samples. Despite the milk processing, including ultra-pasteurization, near-complete genomes were recovered from all samples. Our results revealed non-infectious H5N1 RNA in 27% of 214 milk samples tested across 20 states. We concluded testing pasteurized milk is a useful diagnostic method for detecting H5N1 in cattle. Ultimately, establishing this screening method will allow to develop rapid and reliable data that will enable proper diagnosis and surveillance of this viral outbreak.
Project: Detection of H5N1 virus in pasteurized commercial milk and surveillance in
response to outbreaks in US dairy cattle
Mentors: Elyse Stachler, Ph.D. and Kyle McMahon, Sabeti Lab, Infectious Diseases and
Microbiome Program
