Research ProjectEcology of Marine Parasites and Diseases

Diversity, Distribution, and Host Specificity of Marine Parasites and Disease

  • Kristy and Katrina collect oysters at Punta Chame, Panama.

    Dr. Katrina Lohan and Kristina Hill-Spanik collecting oysters off rocks at Punta Chame, Panama. Photo credit: Carmen Schlöder

  • Kristy, Greg, and Mark looking for oysters in Panama

    Kristina Hill-Spanik and Drs. Greg Ruiz and Mark Torchin collecting oysters from mangroves at Punta Caracol, Panama. Photo credit: Katrina Lohan

  • Ruth DiMaria sampling diseased portions of seagrass leaves from the Indian River Lagoon, Florida.

    Ruth DiMaria sampling diseased leaves from seagrasses collected from the Indian River Lagoon, Florida. Photo credit: Katrina Lohan

Project Goal

We are examining patterns of marine parasite diversity, the host and habitat specificity of different parasites, the ecology of multi-host systems, including potential environmental reservoirs, and the genomic and genetic population diversity of different species and strains of marine parasites.


Parasites are generally much smaller than their hosts, making them notoriously difficult to identify. Some of the larger metazoan parasites* can be viewed using a microscope. However, even most of these larger parasites require additional research tools for species-level identification. Thus, we primarily use DNA markers to identify parasites and examine their population genetic diversity* and structure. Some of the DNA tools we use include Sanger and genomic high throughput sequencing* (454 and Illumina platforms), metabarcoding*, and phylogenetics*.

Our work is examining the diversity and biogeography of parasites along both coasts of North and Central America. While conducting this research, we discovered an invasive oyster in the Caribbean and many parasite species not previously known in Panamanian waters. We continue to explore how bivalve parasite diversity changes with latitude and across coasts. In addition to bivalves, we are also examining the species and population genetic diversity of parasites associated with seagrasses across North America, assessing the host specificity of these parasites in Florida waters and diversity of these parasites associated with the dominant seagrass in temperate and subtropical waters (Zostera marina and Thalassia testudinum). For both of these disease systems, we are also examining the ecology and epidemiology* of the infectious diseases caused by these parasites, which can range dramatically in severity across geographic locations and hosts.

Feature Stories

Parasite Hunting Articles on Shorelines Blog:
Molecular Data Leads to Surprising Discoveries about Oysters in Panamanian Waters. By Katrina Lohan and Monaca Noble. May 2015
A Bite of Bitter Crab. By Katrina Lohan. March 2013
Marine Parasites: Crazy…and Really Cool! By Katrina Lohan. December 2012


Katrina Lohan

Term Definition
Metazoan parasites  Multicellular eukaryotic parasites   
Population genetic diversity  The total number of genetic characteristics in the genetic makeup of a species population.
High throughput sequencing  Faster and less expensive methods of sequencing and analyzing large genomes.
Metabarcoding A method of DNA barcoding that uses universal PCR primers to identify DNA from a mixture of organisms 
Microsatellites A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from 2–5 base pairs) are repeated, typically 5-50 times.
Phylogenetics Phylogenetics is the branch of life science concerned with the analysis of molecular sequencing data to study evolutionary relationships among groups of organisms.