Reef Sediments Can Act As a Stony Coral Tissue Loss Disease Vector

Stony coral tissue loss disease (SCTLD) was first observed in 2014 near Virginia Key in Miami-Dade County, Florida. Field sampling, lab experiments, and modeling approaches have suggested that reef sediments may play a role in SCTLD transmission, though a positive link has not been tested experimentally. We conducted an ex situ transmission assay using a statistically-independent disease apparatus to test whether reef sediments can transmit SCTLD in the absence of direct contact between diseased and healthy coral tissue. We evaluated two methods of sediment inoculation: batch inoculation of sediments collected from southeast Florida using whole colonies of diseased Montastraea cavernosa, and individual inoculations of sediments following independent, secondary infections of ∼5 cm2 coral fragments. Healthy fragments of the coral species Orbicella faveolata and M. cavernosa were exposed to these diseased sediment treatments, as well as direct disease contact and healthy sediment controls. SCTLD transmission was observed for both batch and individual diseased sediment inoculation treatments, albeit with lower proportions of infected individuals as compared to disease contact controls. The time to onset of lesions was significantly different between species and among disease treatments, with the most striking infections occurring in the individual diseased sediment treatment in under 24 h. Following infection, tissue samples were confirmed for the presence of SCTLD signs via histological examination, and sediment subsamples were analyzed for microbial community variation between treatments, identifying 16 SCTLD indicator taxa in sediments associated with corals experiencing tissue loss. This study demonstrated that reef sediments can indeed transmit SCTLD through indirect exposure between diseased and healthy corals, and adds credence to the assertion that SCTLD transmission occurs via an infectious agent or agents. This study emphasizes the critical need to understand the roles that sediment microbial communities and coastal development activities may have on the persistence of SCTLD throughout the endemic zone, especially in the context of management and conservation strategies in Florida and the wider Caribbean.

Urbanization favors the proliferation of Aedes aegypti and Culex quinquefasciatus in urban areas of Miami-Dade County, Florida

Urbanization processes are increasing globally. Anthropogenic alterations in the environment have profound effects on biodiversity. Decreased biodiversity due to biotic homogenization processes as a consequence of urbanization often result in increased levels of mosquito vector species and vector-borne pathogen transmission. Understanding how anthropogenic alterations in the environment will affect the abundance, richness, and composition of vector mosquito species is crucial for the implementation of effective and targeted mosquito control strategies. We hypothesized that anthropogenic alterations in the environment are responsible for increasing the abundance of mosquito species that are adapted to urban environments such as Aedesaegypti and Culexquinquefasciatus. Therefore, our objective was to survey mosquito relative abundance, richness, and community composition in Miami-Dade County, Florida, in areas with different levels of urbanization. We selected 24 areas, 16 remote areas comprised of natural and rural areas, and 8 urban areas comprised of residential and touristic areas in Miami-Dade County, Florida. Mosquitoes were collected weekly in each area for 24 h for 5 consecutive weeks from August to October 2020 using BG-Sentinel traps baited with dry ice. A total of 36,645 mosquitoes were collected, from which 34,048 were collected in the remote areas and 2,597 in the urban areas. Our results show a clear and well-defined pattern of abundance, richness, and community composition according to anthropogenic modifications in land use and land cover. The more urbanized a given area the fewer species were found and those were primary vectors of arboviruses, Ae.aegypti and Cx.quinquefasciatus.

Strong Population Genetic Structure and Cryptic Diversity in the Florida Bonneted Bat (Eumops Floridanus)

Knowledge of genetic structure is essential for the long-term management and conservation of endangered species. We report the results from a genetic examination of the federally endangered Florida bonneted bat (Eumops floridanus) sampled from its range in southern Florida, USA. Bonneted bats are primarily found in four regions separated by approximately 100 to 250 kms, including three western natural areas (BW, PC, and CC) and one urban population on the east coast [Miami-Dade County (MD)]. We used 22 microsatellite loci and cytochrome b sequences to assess the extent of connectivity and levels of genetic diversity. Regional populations were highly differentiated (FST = 0.178) and model-based and multivariate analyses showed that MD was the most distinct among pairwise comparisons. Regional populations are small (i.e., Ne < 100) but demographically stable. Estimates of contemporary migration and historic gene flow suggest that regional populations do not frequently exchange migrants, but simulations suggest that the divergence among western regions is likely a result of recent genetic drift rather than long-term isolation. Significantly, mitochondrial DNA revealed that haplotypes from MD were similar or shared with those recognized as Eumops ferox from Cuba and Jamaica, and divergent (1.5%) from the remainder of bonneted bats in Florida. Our data support the management of each of the four populations as distinct population segments, and that BW, PC and CC combined are on an independent evolutionary trajectory from bats in MD. Critically, bonneted bats in Florida appear to harbor cryptic diversity that will require a reassessment of their taxonomy.

A molecular surveillance-guided vector control response to concurrent dengue and West Nile virus outbreaks in a COVID-19 hotspot of Florida

Simultaneous dengue virus (DENV) and West Nile virus (WNV) outbreaks in Florida, USA, in 2020 resulted in 71 dengue virus serotype 1 and 86 WNV human cases. Our outbreak response leveraged a molecular diagnostic screen of mosquito populations for DENV and WNV in Miami-Dade County to quickly employ targeted mosquito abatement efforts. We detected DENV serotypes 2 and 4 in mosquito pools, highlighting the silent circulation of diverse dengue serotypes in mosquitoes. Additionally, we found WNV-positive mosquito pools in areas with no historical reports of WNV transmission. These findings demonstrate the importance of proactive, strategic arbovirus surveillance in mosquito populations to prevent and control outbreaks, particularly when other illnesses (e.g., COVID-19), which present with similar symptoms are circulating concurrently. Growing evidence for substantial infection prevalence of dengue in competent mosquito vectors in the absence of local index cases suggests a higher level of dengue endemicity in Florida than previously thought.

Reconceptualizing disaster phases through a Metis-based approach

PurposeThis paper aims to call for change in disaster research through a metis-based approach that values practical skills and knowledge (vs technical knowledge) derived from responding to ongoing changes in the natural and human environment.Design/methodology/approachThis paper is based on metis from Miami-Dade County that is prone to an array of climate-related disasters. Metis is supplemented by a review of secondary sources (e.g. newspaper articles, government reports).FindingsThere is a need to reconceptualize disaster phases in disaster research—preparedness, response, recovery and mitigation. For many members of marginalized communities of color, this paper depicts preparedness and mitigation as luxuries and response as a time of worry about financial obligations and survival after the disaster. It suggests that even communities that are not on a hurricane's path could have post-disaster experiences. It also highlights ongoing risks to marginalized communities' physical and mental well-being that are in addition to the mental health impacts of the disaster during the recovery phase.Originality/valueThis paper's originality is twofold: (1) underlining the importance of metis, a less studied and understood concept in disaster risk reduction, prevention and management literature and (2) questioning disaster researchers' technical knowledge with respect to each of the four disaster phases in light of metis.

Multi-Variate Analyses of Coral Mortality From the 2014–2015 Stony Coral Tissue Loss Disease Outbreak Off Miami-Dade County, Florida

Environmental compliance monitoring associated with the Port Miami dredging project (2013–2015), designed to assess the impact of project-generated sediments on the local coral community, fortuitously captured a thermal bleaching event and the first reports of an emergent, highly contagious, white-plague-like coral disease outbreak in the fall of 2014. The disease, now termed stony coral tissue loss disease (SCTLD), has decimated reefs throughout Florida and is now spreading across the Caribbean. The high prevalence of disease, the number of affected species, and the high mortality of corals affected suggests SCTLD may be the most lethal coral disease ever recorded. Previous analyses of the dredge monitoring data have reached mixed conclusions about the relative impact of dredging on coral mortality and has often parsed out disease susceptible individuals to isolate the impacts of dredging only. We use multi-variate analyses, including time-based survival analyses, to examine the timing and impacts of dredging, coral bleaching, and disease on local coral mortality. By examining the status of corals monthly from the October 2013 to July 2015 observational period, we found that coral mortality was not significantly affected by a coral’s proximity to the dredge site or sediment burial. Instead, coral mortality was most strongly impacted by disease and the emergence of SCTLD during the monitoring period. During the 2-year monitoring period, 26.3% of the monitored corals died, but the only conditions significantly affected by the dredge were partial burial and partial mortality. The strongest link to mortality was due to disease, which impacted coral species differently depending on their susceptibility to SCTLD. The focus on disturbances associated with dredging created a circumstance where the greater impacts of this emergent disease were downplayed, leading to a false narrative of the resulting mortality on the local coral communities. The results of this study reveal that while local events such as a dredging project do have quantifiable effects and can be harmful to corals, regional and global threats that result in mass coral mortality such as thermal stress and disease represent an existential threat to coral reefs and must be urgently addressed.