Award Abstract # 0640892
Urbanization and macroparasite infection of amphibians


Overview: A two-year program is proposed during which we will apply a high frequency ultrasound system as a tool for noninvasive diagnosis of macroparasite infection in amphibian hosts. During the proposed research we will evaluate the following hypotheses using a combination of observations and experiments:

Hypothesis I: Urbanization leads to emergence of helminthic disease.
Hypothesis II: Mortality is dependent on host kidney development.
Hypothesis III: Echinostome infection increases larval mortality rates in natural populations.
Hypothesis IV: Mortality is greater in urbanized settings:
    a. Because echinostome exposure rates at critical development periods are greater.
    b. Because host immune function is compromised in urbanized settings.

    c. Because of increased first intermediate host snail density.

Intellectual Merit: Understanding the relationship between parasites and their hosts is a longstanding goal for ecologists. This interest in infection and its consequences has been heightened by emerging disease phenomena. One particular focus of study is the relationship between anthropogenic alteration of landscapes and its implications for hostparasite interactions. As an example, diseases of host animals may emerge when humans urbanize landscapes. We propose to use new methods to evaluate urbanization and disease emergence in a system, amphibians and their trematode parasites, for which we have abundant prior data. Our previous findings, based on contemporary sampling across a gradient of human density and development, suggest that infection by echinostomes is increased as environments become urbanized. Here, we propose the use of a new high resolution ultrasound system to mine information from museum specimens collected during the last two centuries. Temporal trends uncovered in this historical analysis will be interpreted in light of proposed research (observations and experiments) allowing us to examine host responses and the impact of infection in relation to the degree of urbanization.

Broader Impacts: Funding of this proposal will contribute to the education of the graduate student investigator, a doctoral student, and facilitate pursuit of her career goal of becoming an academic ecologist. We will involve undergraduate students in each phase of the research. Their research experiences will form the basis of senior theses. Finally, we will develop an exhibit featuring this research at the Yale Peabody Museum of Natural History. This exhibit will reach a large audience of nonscientists. We will further enhance the impact of this activity by involving a group of six New Haven high school students in understanding how urbanization influences the ecosystems in which they live.