About This Project

Leptospirosis is a potentially life-threatening bacterial infection of humans and other mammals which can lead to organ failure and/or meningitis. Rodents abundant in urban and rural environments are the most important reservoirs and sources of Leptospira infection. This study is an investigation of the non-native rodent, Nutria, and their association with an increase in Oregon cases.

Ask the Scientists

What is the context of this research?

Historic cases of Leptospirosis in Oregon have been infrequent and tied to the coast where breakouts cause sudden mortalities in sea lion and seal populations. In the last few years, however, human and animal cases in Oregon have increased dramatically. Rodents are known to be reservoirs for this bacterial parasite worldwide, often having no symptoms and passing their infection to other mammals by shedding the bacteria in their urine and contaminating water sources. For this reason, infections are associated with areas where rainfall and flooding are common. Nutria, Myocastor coypus, a large semi- aquatic rodent introduced to Oregon, have been shown to both carry and spread this bacterial parasite.

What is the significance of this project?

The WHO has estimated that there are 873,000 human cases annually worldwide. Wildlife cases are not always tracked, so the impact of this parasite is not fully understood. Identifying local reservoirs of this disease would greatly inform management practices of wildlife, veterinary vaccination protocols, and reduce the chance of misdiagnosis within human medical practices in Oregon. Although some vaccines for Leptospirosis exist for both humans and animals, administration is optional for livestock and pet owners and no public information is available for human vaccination rates in Oregon. If there is sufficient information about prevalence and risk, interest in promoting or developing more modern vaccines could change treatment worldwide.

What are the goals of the project?

The goal of this project is to investigate whether or not nutria are playing a role in the increased incidence of leptospirosis cases. our goals are: 1, estimate the proportion of nutria in western Oregon that carry the disease, 2, estimate the density of nutria in urban and disturbed wetlands, and 3, investigate methods of detecting Leptospira in water samples. The first goal is going to be completed by directly testing kidney tissue samples from nutria from multiple western Oregon counties. The second and third goals will be completed by using eDNA methods to correlate density of nutria in a waterbody to density of nutria DNA and Leptospira DNA in water samples collected from that waterbody.