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Dengue surveillance in Florida, 1997-98, is discussed with the conclusion that the risk for local dengue transmission may be increasing. Outbreaks in the Caribbean and nearby areas have increased the probability of future autochthonous transmission in that state. A laboratory-based active surveillance program found 18 cases involving the four dengue serotypes, 4/97-3/98, and all patients had traveled to countries with indigenous dengue transmission., Recent dengue outbreaks in the Caribbean and Central and South America and the presence of competent mosquito vectors increase the likelihood of future autochthonous transmission in Florida. During April 1997 [...]

In North America, before the introduction of West Nile virus (WNV; Flavivirus, Flaviviridae) in 1999, St. Louis encephalitis virus (SLEV; Flavivirus, Flaviviridae) was the most important agent of epidemic viral [...]

Abstract Background Eastern Equine Encephalitis virus (EEEV) is an alphavirus with high pathogenicity in both humans and horses. Florida continues to have the highest occurrence of human cases in the USA, with four fatalities recorded in 2010. Unlike other states, Florida supports year-round EEEV transmission. This research uses GIS to examine spatial patterns of documented horse cases during 2005–2010 in order to understand the relationships between habitat and transmission intensity of EEEV in Florida. Methods Cumulative incidence rates of EEE in horses were calculated for each county. Two cluster analyses were performed using density-based spatial clustering of applications with noise (DBSCAN). The first analysis was based on regional clustering while the second focused on local clustering. Ecological associations of EEEV were examined using compositional analysis and Euclidean distance analysis to determine if the proportion or proximity of certain habitats played a role in transmission. Results The DBSCAN algorithm identified five distinct regional spatial clusters that contained 360 of the 438 horse cases. The local clustering resulted in 18 separate clusters containing 105 of the 438 cases. Both the compositional analysis and Euclidean distance analysis indicated that the top five habitats positively associated with horse cases were rural residential areas, crop and pastureland, upland hardwood forests, vegetated non-forested wetlands, and tree plantations. Conclusions This study demonstrates that in Florida tree plantations are a focus for epizootic transmission of EEEV. It appears both the abundance and proximity of tree plantations are factors associated with increased risk of EEE in horses and therefore humans. This association helps to explain why there is are spatially distinct differences in the amount of EEE horse cases across Florida.

Hamimeda is a prominent part of the calcifying algae in the coral-reef lagoon ecosystems in the Caribbean. Experiments were performed on the Cayo Enrique Reef off Puerto Rico and in the laboratories of the University of Maryland to study factors influencing the calcification processes. Halimeda opuntia has a higher percentage of calcium carbonate than does Halimeda discoidea and a faster rate of incorporation. Halimeda Opuntia and Halimeda discoidea show a slimulation of incorporation by light as well as a diurnal rhythm under identical conditions of illumination. Both Phenomena parallel the rhythm of chloroplast migration within the plant. Calcification is also slimulated by the addition of carbon dioxide. Such evidence clearly indicated a light-linked mechanism which could involve photosynthesis. However other metabolic processes, such as respiration, are also implicated. Acration alone accelerates calcium incorporation. Nitrogen sources inhibit the incorporation of calcium during the day, indicating that cellular ammonia production is probably not responsible for precipitation. The dif- [ABSTRACT FROM AUTHOR]

Wild caught rock pigeons (Columba livia) with antibodies to West Nile virus were monitored for 15 months to determine antibody persistence and compare results of three serologic techniques. Antibodies persisted for the entire study as detected by epitope-blocking enzyme-linked immunosorbent assay and plaque reduction neutralization test. Maternal antibodies in squabs derived from seropositive birds persisted for an average of 27 days.