Discipline: Biological Sciences
Subcategory: Microbiology/Immunology/Virology
Session: 2
Makeda Mills - University of the Virgin Islands
Co-Author(s): D'Shaunique Walters, University of the Virgin Islands ; Shakilah Liburd, University of the Virgin Islands ; Antonae Anthony, University of the Virgin Islands ; PhD Jennilee Robinson, University of the Virgin Islands ; PhD Andrew Campbell, Brown University PhD Paul Sikkel, Arkansas State University
Apicomplexa are intracellular protozoan parasites that infect a wide array of host animals including; birds, reptiles, fish, invertebrates, humans, and other mammals. Apicomplexa are responsible for severe human diseases such as cryptosporidiosis, toxoplasmosis and malaria. However, little is known about other natural apicomplexan infections. In the Caribbean, some of the most abundant coral reef fish, Stegastes adustus (dusky damselfish) are infected with apicomplexans in their red blood cells. In order to characterize the host range, life cycle, and route of transmission of these parasites, our goal is to develop methods to isolate and detect them in infected fish blood samples. Unfortunately, as This study was conducted on the island of St. Thomas, U.S Virgin Islands which suffered the impacts of two hurricanes in September of 2017, we believe it may affect the infection rate of this apicomplexa. Thus, we hypothesize that the number of apicomplexan infections in the dusky damselfish will be distinct from the previous years (2015-2017). In order to test our hypothesis, we captured 10-15 dusky damselfish from their natural reef habitat at twelve different sites, collected blood, and released them. At each site, a 25m line transect was used to record the density of all six Stegastes species, as well as Stegastes adustus. We developed several detection and isolation methods which include screening of 3% Giemsa-stained thin blood smears by microscopy. Overall, the infection pattern resembled a Poisson distribution with some sites having high prevalence, and others with none. The average prevalence of infected fish decreased from 49.9%?23.6% for fish collected in 20515-2017 (n=80) to 26.1?29.6% after the hurricanes (n=130)
This data leads into further research to discover whether or not this decline in the infection affects the population of dusky damselfish and other animals on the reef. We would imagine that noted behavioral observations in competition and overall performance would give some insights to how the parasite affects the declared infected fish vs uninfected fish. More so, as there is no record of the life cycle of this parasite, we look forward to using Percoll density-step gradients and western blot analysis in order to gather additional data to accurately classify this parasite. From this point, we would be able to culture and monitor the parasites to get a better understanding of their life cycle and why the infection rate declined after the hurricanes.
Funder Acknowledgement(s): NSF HBCU-UP Scholars #1137472Emerging Caribbean Scientists Program
Faculty Advisor: Dr. Jennilee Robinson, jrobins@uvi.edu
Role: I participated in every aspect of this research. Myself, along with the co-authors went out on the water to catch the fish for this study, bled them then released them back to their home reefs. Then, we stained the thin blood smears with 3% Giemsa stain then proceed to microscopy.