Valerie Cortez, PhD MS

Activity in Julie Overbaugh's lab at FHCRC

Nominated From: University of Washington

Research Site: Peru

Research Area: Infectious Disease

Primary Mentor: Daniel Bausch

Research Project

Emerging Infectious Diseases in the Peruvian Amazon: Using Detection of Leptospirosis in Rodents and Humans as a Measure of Habitat Disruption

Bacterial pathogens from the genus Leptospira, have recently gained attention from the research community as an emerging public health problem. Interestingly, leptospirosis has been endemic to Peru as far back as 1917, but climate and habitat change appear to be associated with the recent increase in outbreaks. Leptospirosis ranks number three in the list of the top infectious hazards in the Americas reported in the Event Management System that supports the International Health Regulations. The true prevalence of leptospirosis is likely higher than current estimates, as the disease is often underdiagnosed and therefore underreported. Underdiagnosis is partially due to the non-specific symptoms of the disease that can range from mild flu-like illness to organ failure. The WHO estimates that the annual incidence ranges from 0.1 per 100,000 individuals in temperate climates to greater than 10 per 100,000 individuals in tropical climates, which translates to over a million severe cases each year, 10-40% of which are fatal. Recent reports highlight an urgent need for point-of-care diagnostics, regular surveillance, and appropriate control measures to prevent future epidemics.

With the support of Dr. Bausch and team members, I aim to survey the rodent reservoir of leptospirosis and environmental exposures in communities near the Trans-Oceanic Highway in Madre de Dios, Peru. To accomplish this, I propose the following aims:

1. To determine the change in prevalence of leptospirosis in rodent populations from the dry and rainy seasons in Madre de Dios, Peru.
2. To identify environmental sources of Leptospira to which humans living in the surrounding communities are exposed.
3. To assess whether circulating Leptospira in rodent populations are closely related to species from environmental sources by phylogenetic analysis.


Research Significance

The Amazon Rainforest has sustained considerable habitat perturbation as a result of land use changes for economic purposes including agriculture, logging, and mining. As these changes continue, there is an urgent need to assess the potential risk of zoonotic transmissions to humans in the local communities. The recent completion of the Trans-Oceanic Highway though the southern Amazon in Peru, represents the latest shift in ecology within the region. Researchers at NAMRU-6 and collaborators seek to survey the effects of the new highway by monitoring the rodent population dynamics and rodent-borne disease prevalence in this region over the next 5 years. This team of researchers, led by Dr. Daniel Bausch, aims to collect samples from trapped rodents and test them for a variety of bacterial and viral pathogens.

While the scope of this proposal is focused on a single bacterial pathogen, results from this study will yield insights to the impact of climate and global change on biodiversity of small mammal populations and their associated microbial communities. The consequences of habitat perturbation on human and animal health cannot be overstated, and additional surveillance and risk assessment will be essential for future public health policy and prevention.




View on PubMed