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Current Research

Surveillance and Monitoring of Chronic Wasting Disease in Florida’s Deer

The Fish and Wildlife Health Team continues to monitor for Chronic Wasting Disease (CWD), a nervous system disease that is fatal to deer. The data obtained in an assessment study has helped detect the first positive case of CWD in Florida. 

More information on CWD in Florida.

Investigation Of Cutaneous Ulcers Affecting Invasive Lionfish Pterois spp. In The Gulf Of Mexico

Epizootic, cutaneous ulcerative skin lesions in a complex of invasive lionfish (Pterois volitans, P. miles and the hybrid P. volitans x P. miles) were first observed in the Gulf of Mexico in mid-August 2017. Typical lesions exhibited exposed skeletal muscle and were bordered by pale or reddened areas often with some degree of scale loss. Gross and histopathological examination of tissues showed most fish (86%; n = 50) were healing based on the presence of granulation tissues. Neither bacterial culture nor histopathology indicated a primary bacterial pathogen. Unbiased metagenomic next generation sequencing on a subsample of ulcerated fish did not reveal a viral pathogen. Results suggest a potential role for opportunistic bacteria, though our suite of diagnostics did not reveal an intralesional infectious agent. A comparison of general health indicators between clinically healthy and ulcerated fish (condition factor, splenosomatic and hepatosomatic index) showed that fish with ulcers had a significantly lower condition factor and a higher splenosomatic index. Fish with ulcers tended to be older than those without, but sex was not an apparent risk factor. Continuous monitoring of sites to track the prevalence of the disease shows it is still detectable today but at much lower levels.

Read the full article in the Journal of Aquatic Animal Health.

Characterization of Antibiotic-Resistant Bacteria in Marine Sport Fish

Antibiotic-resistant, disease-causing bacteria have posed serious issues for human and domestic animal health over the last few decades. Misuse and overuse of antibiotics by humans, their general use as additives for disease prevention in livestock feed, use in veterinary medicine, and aquaculture practices have all contributed to generating antibiotic-resistant bacteria by mutation through selective pressures. The antibiotic-resistant bacteria are excreted as waste from humans and animals, and they eventually reach the aquatic environment through effluent from wastewater treatment plants, sewage spills, urban surface water run-off, or agricultural activities. Researchers have found antibiotic-resistant bacteria in the digestive tracts of marine mammals, sea turtles, and fish indicating that these aquatic animals function as reservoirs of antibiotic-resistant bacteria. Monitoring the antibiotic resistance of indicator bacteria like Enterococcus species in aquatic organisms helps us to understand the biological mechanisms involved in the distribution of antibiotic-resistant bacteria and how antibiotic resistance genes are transferred. Enterococcus spp. are used as indicators for water quality, but very little is known about their interactions with marine and estuarine fish and whether these animals serve as reservoirs and vectors for antibiotic resistant bacteria. Therefore, the aim of this study was to collect information about the prevalence of the fecal indicator bacteria, Enterococcus spp. in the intestinal contents of several marine sport fish species and to characterize antibiotic resistance patterns among the fish species.