Indian River County Research Articles

First Report of Mixed Infection of Jasmine Mosaic-Associated Virus (JMaV) and Jasmine Virus H (JaVH) in Jasmine Species in Florida, United States

Over the past 24 years, virus-like symptoms have been observed on Jasminum spp. in Florida. In September 2018, symptomatic Angelwing jasmine leaves from a hedge in Alachua, Florida, were tested for jasmine mosaic-associated virus (JMaV) and jasmine virus H (JaVH). Identification of expected size amplicons was confirmed by sequencing (accession numbers MN245037, MT559755). In December 2018, symptomatic samples from two Gold Coast jasmine plants from St. Lucie County, Florida, were similarly tested. Only JaVH tested positive (accession number MN442626). In July 2019, Angelwing jasmine hedge in Orange County, Florida, exhibiting similar symptoms tested positive only for JaVH (GenBank accession number MN442627). In April 2023, samples from a symptomatic Gold Coast jasmine hedge in Indian River County, Florida, also tested positive only for JaVH. In May 2023, a symptomatic Angelwing jasmine sample from Miami-Dade County tested positive for both JMaV and JaVH. This is the first report of JMaV and JaVH in single or mixed infections in jasmine in Florida, adding to the known virus species infecting jasmine in the state. Because jasmine is propagated vegetatively, it is likely that dissemination of cuttings made from infected plants is responsible for widespread distribution of these viruses.

Mosquito Communities Vary across Landscape and Vertical Strata in Indian River County, Florida

Mosquito and arbovirus surveillance is essential to the protection of public health. A majority of surveys are undertaken at ground level. However, mosquitoes shelter, breed, and quest for hosts across vertical strata, thus limiting our ability to fully describe mosquito and arboviral communities. To elucidate patterns of mosquito vertical stratification, canopy traps were constructed to sample mosquitoes at heights of 1.5, 5.0, and 8.7 m across three different landscape types in a Florida coastal conservation area. We assessed trapping efforts using individual-based rarefaction and extrapolation. The effects of height, landscape, site location, and sampling date on mosquito community composition were parsed out using permutational ANOVA on a Hellinger-transformed Bray–Curtis dissimilarity abundance matrix. Lastly, a generalized linear mixed effects model (GLMM) was used to explore species-specific vertical patterns. We observed differences in sampling effort and community composition structure across various heights and landscapes. Our GLMM revealed significant effects of trap height for Aedes taeniorhynchus, Anopheles crucians, Anopheles quadrimaculatus, and Culex coronator, but not for Culex nigripalpus, the ultra-dominant species present in this area. Together these data provide evidence that height and landscape significantly affect mosquito community structures and highlight a need to develop sampling regimes to target specific vector and nuisance species at their preferred height and across different landscape types.

Florida's Strategic Position for Collaborative Automated Telemetry Tracking of Avian Movements Across the Americas

Florida's Strategic Position for Collaborative Automated Telemetry Tracking of Avian Movements Across the Americas

Artificial intelligence based approaches to evaluate actual evapotranspiration in wetlands

Wetlands are extraordinary ecosystems and important climate regulators that also contribute to reduce natural disaster risk. Unfortunately, wetlands are declining much faster than forests. The safeguarding of the wetlands also needs knowledge of the dynamics that control the water balance of these environments. Therefore, an accurate estimation of evapotranspiration in wetlands is an essential task.When adequate experimental data are available, some algorithms deriving from Artificial Intelligence research represent a promising alternative to the most common estimation techniques.In this study, starting from daily measurements of climatic variables such as net solar radiation, depth to water, wind speed, mean relative humidity, maximum temperature, minimum temperature, and mean temperature, using the Random Forest, Additive Regression of Decision Stump, Multilayer Perceptron and k-Nearest Neighbors algorithms, 24 estimation models, different in input variables, have been developed and compared. The data have been provided by USGS. They have been obtained from a measuring site in wetlands of Indian River County, Florida using the eddy-covariance technique.The accuracy of these models based on AI algorithms remains good even if the number of input variables is reduced from 7 to 3. Net solar radiation, mean temperature and mean relative humidity or wind speed measurements allow obtaining a sufficiently accurate estimation model. Random Forest and k-Nearest Neighbors provide slightly better performance than Additive Regression of Decision Stump and Multilayer Perceptron. The analyzed models show in most cases the lowest accuracy in the range 2–4 mm/day, while the highest accuracy is obtained in the ranges 0–2 mm/day and 6–8 mm/day, with the exception of the models based on the Additive Regression, which show similar levels of accuracy in the different considered sub-intervals.

Vertebrate Hosts ofAedes aegypti,Aedes albopictus, andCulex quinquefasciatus(Diptera: Culicidae) as Potential Vectors of Zika Virus in Florida

Zika virus (ZIKV), once considered an obscure pathogen, spread rapidly from 2014 to 2016 to become an internationally notifiable condition of major public health concern. The relative importance of various Culex and Aedes species mosquitoes (Diptera: Culicidae) in ZIKV transmission is a topic of debate. Quantifying host use is important in determining the vectorial capacity of a mosquito species for transmitting ZIKV in nature. In the United States, few data are available on host use of Aedes aegypti L. (Diptera: Culicidae) and Aedes albopictus (Skuse) (Diptera: Culicidae), confirmed and suspected vectors of ZIKV, respectively. Here, we report results of bloodmeal analysis to quantify host use of confirmed (Ae. aegypti) and suspected (Ae. albopictus and Culex quinquefasciatus Say (Diptera: Culicidae)) vectors of ZIKV in two Florida counties. At an auto salvage yard in Indian River County, Ae. aegypti, Ae. albopictus and Cx. quinquefasciatus fed mainly on humans, taking 90.2, 90.8, and 78.6% of bloodmeals from humans, respectively. At a residential area in Martin County, Ae. aegypti, Ae. albopictus took 61.5 and 66.7% of bloodmeals from humans, higher than Cx. quinquefasciatus (11.1%). Patterns of host use suggest that Ae. aegypti and Ae. albopictus are the most likely vectors of ZIKV in Florida and that Cx. quinquefasciatus would likely play a lesser role in ZIKV transmission in Florida. However, the relative importance of the three species in ZIKV transmission is likely location and population specific. Detailed studies quantifying other parameters of vectorial capacity, including vector competence, are needed in order to determine the actual role for each species in ZIKV transmission.

Rootstock Effects on Fruit Quality among ‘Ray Ruby’ Grapefruit Trees Grown in the Indian River District of Florida

The objective of this experiment was to compare fruit-quality parameters of ‘Ray Ruby’ grapefruit grown on seven rootstocks. Four recent releases from the United States Department of Agriculture (USDA) rootstock breeding program, ‘US-852’, ‘US-897’, ‘US-942’, and ‘US-812’ (all Citrus reticulata × Poncirus trifoliata hybrids), ‘x639’ (C. reticulata × P. trifoliata), along with industry-standard ‘Sour Orange’ and ‘Swingle’ citrumelo were evaluated in a commercial orchard trial in Indian River County, FL. Fruit-quality data were collected in 2011–12 (eight harvests), 2012–13 (five harvests), and 2014 (single harvest). In each season, rootstock effects on fruit size, total solids, and solids acid ratio were significant. ‘Sour orange’ and ‘Swingle’ produced the largest fruit, whereas ‘US-897’ (a semidwarfing rootstock) produced the smallest fruit. Peel thickness (measured only in the 2011–12 season) was greatest in ‘Sour Orange’ early in the season, but not toward the end of the season. Misshapen (“sheep-nosed”) fruit occurred more frequently on ‘Sour Orange’ than on other rootstocks, although the incidence of sheep-nosing was minor. Analysis of variance (ANOVA) for fruit-quality data collected in January of each of the 3 years confirmed that ‘Sour Orange’ and ‘Swingle’ produced the largest fruit and ‘US-897’ produced the smallest fruit. Total solids were the highest in ‘US-897’ and the lowest in ‘x639’ and ‘US-852’. Taken together, our data indicate that ‘US-942’ and ‘US-897’ rootstocks produced fruit with quality characteristics that equaled or exceeded ‘Sour Orange’ and ‘Swingle’, the two most common rootstocks used in the Indian River district.

Testing of Visual and Chemical Attractants in Correlation with the Development and Field Evaluation of an Autodissemination Station for the Suppression of Aedes aegypti and Aedes albopictus in Florida.

Three exotic mosquito-borne pathogens-dengue, chikungunya, and Zika viruses-transmitted by Aedes albopictus and Ae. aegypti have undergone dramatic global expansion in recent years. The control of vector populations and minimizing bites from these vectors are the primary methods of reducing risk of transmission of these viruses to humans. However, Ae. albopictus and Ae. aegypti are notoriously challenging to control through conventional chemical means, due primarily to difficulties in applying pesticides to their cryptic larval habitats. A novel strategy for suppressing populations of these species is the autodissemination of insect growth regulators (IGRs), in which adult female mosquitoes are attracted to a treatment station where they are tainted with small amounts of potent IGR. When the adult females subsequently visit oviposition sites, they inadvertently disseminate the IGR to larval development sites, suppressing their own population. Implementing this technology to control natural vector populations presents substantial logistical challenges. The current manuscript describes laboratory bioassays and field evaluations to design a novel autodissemination station (ADS) and test the methodology at field locations in Florida where Ae. aegypti and Ae. albopictus are abundant and pose a risk for transmission of emerging pathogens. The prototype ADS is intended to attract host-seeking, resting site-seeking, and oviposition site-seeking females through a combination of visual and olfactory cues. The efficacy of this strategy was assessed through the use of sentinel ovicups at field locations in Indian River County and Martin County, FL. Greatest efficacy (45.3 ± 7.7% mortality in treatment sentinel ovicups) was achieved at a field site with few competing natural ovisites, while much lower efficacy was observed in locations with numerous competing ovisites (0.0 to 29.0 ± 8.2% mortality). The efficacy of the ADS is likely to be strongly affected by the abundance of competing ovisites, the population dynamics, and climatic conditions.

Aedes pertinax, a Newly Recognized Mosquito Species in the United States.

Specimens of a mosquito new to the continental USA, Aedes pertinax, were retrospectively identified from 2 collections made in 2011 in Indian River County, FL. Routine mosquito surveillance in subsequent years yielded more than 700 specimens appearing in 100 collections. The distribution of this mosquito in Florida and the United States is currently unknown, and recognition of the adult female is likely hampered by morphological similarities to Ae. atlanticus and Ae. tormentor.

Relating fibropapilloma tumor severity to blood parameters in green turtles Chelonia mydas.

Fibropapillomatosis is a neoplastic disease that is commonly found in the green turtles Chelonia mydas in tropical and subtropical regions of the world. In the current project, juvenile green turtles were captured with large-mesh tangle nets in the Indian River Lagoon and on nearshore reefs of Indian River County, Florida, USA, in 1998 and 1999. The purpose of the study was to determine the relationship between the severity of the disease and the general health of green turtles as indicated by blood parameters. All turtles were measured and examined, and the overall severity of the disease was rated by the size, number, and location of external fibropapilloma tumors. Hematocrit, total protein, and hemoglobin concentration were measured and compared with tumor scores (tumor severity appraisal). As the tumor score increased, the blood parameters of turtles decreased; for instance, the percentage of decrease in hematocrit for mildly afflicted, moderately afflicted, and severely afflicted groups were 2.6, 18.3, and 45.5%, respectively. Severely afflicted turtles suffered from anemia, while individuals with mild affliction did not.

Vector competence of Culex pipiens quinquefasciatus (Diptera: Culicidae) for West Nile virus isolates from Florida.

To assess vector competence (infection, dissemination and transmission) of Culex pipiens quinquefasciatus for Florida (FL) West Nile virus (WNV) isolates. West Nile virus isolates (WN-FL-03: NY99 genotype; WN-FL-05-558, WN-FL-05-2186, WN-FL-05-510: WN02 genotype) collected from different regions of FL were used for vector competence experiments in Cx. p. quinquefasciatus from Alachua County and Indian River County in FL. Mosquitoes from both colonies were fed blood containing 7.9 ± 0.2 log10 plaque-forming units WNV/ml ± SE and incubated at 28 °C for 14 days. Vector competence, including rates of infection, dissemination, and transmission, was compared between colonies for WN-FL-03 using chi-squared. Virus titres in bodies, legs and saliva were compared using anova. Daily measurements of in vitro replication of WNV isolates were evaluated in Vero cells so that a standardised virus dose for each isolate could be delivered to mosquitoes. Infection and dissemination rates were high (≥ 95%) and not affected by isolate or colony (infection, P = 0.679; dissemination, P = 0.799). Transmission rates were low (≤ 20%), detected in one colony and affected by isolate (P = 0.008). Body and leg titres differed between isolates (body titre, P = 0.031; leg titre, P = 0.044) and colonies (body titre, P = 0.001; leg titre, P = 0.013) while saliva titre did not differ between isolates (P = 0.462). Variation in vector competence of mosquito populations may be attributed, in part, to exposures to WNV with genetic differences leading to different rates of replication in mosquitoes. Evaluation of vector competence for different WNV isolates may help us understand vector-virus interactions and, hence, the role of vectors in complex virus transmission cycles in nature.

Profiles in History

1940S On April 5, 2014, a member of “the greatest generation,” Hal L. Hill passed away in Bakersfield, CA. Hal Hill was born in Syracuse, NE in 1920. He graduated from the University of Nebraska and also served in World War II. After the war, Hill worked for 28 yr in the United States Department of Agriculture–Soil Conservation Service. Hal Hill in uniform during World War II. Hill's career with USDA-SCS began in Nebraska where he worked during the mapping season, and during the cold snowy winters he was detailed to the South to help finish ongoing soil surveys in Louisiana. Hill later moved to California's San Joaquin Valley, where as a USDA-SCS employee working with University of California soil scientists, he helped finish field work for the Soil Survey of Madera Area, California. He also worked on the Soil Survey of Eastern Fresno Area, California before completing his career in Bakersfield, where he was the project leader for the Soil Survey of Kern County, California, Southeastern Part. Information courtesy of Kerry Arroues and Kim Chang, soil scientists, USDA-NRCS (retired), and Hill's obituary as printed in the Bakersfield Californian. 1991 The Northeast Regional Soil Judging Competition was hosted by Delaware Valley College (DVC) in 1991. Preparing a soil pit for judging on a glacial outwash plain near Washington's Crossing, PA are (left to right): Paul Golrick, Del Val Soil Consultants, Inc.; Joe Valentine, Del Val Soil Consultants, Inc. and adjunct instructor at DVC; Pennsylvania Assistant State Soil Scientist–Correlation, Ed White, USDA-SCS; Scott Anderson, Soil Survey Party Leader, USDA-SCS; and Milton Cortes, Soil Scientist, USDA-SCS. Soil judging in southeastern Pennsylvania. Joe Valentine, a consulting soil scientist, continues as an adjunct instructor at DVC, which hosted the 2014 National Soil Judging Competition in April. Joe was the event coordinator. Ed White retired in 2012 as State Soil Scientist of Pennsylvanian and assisted with the scoring at the 2014 national event. Scott Anderson is now Senior Regional Soil Scientist at the Regional Soil Survey Office in Auburn, AL, while Milton Cortes is Assistant State Soil Scientist in Raleigh, NC. Paul Golrick is a soil scientist and a professional geologist at Penn's Trail Environmental, Inc., where he is also a partner in the company. Paul gave a presentation on local geology at the 2014 national event. Photo courtesy of John Chibirka, USDA-NRCS soil scientist in Pennsylvania, who also assisted with the official soil descriptions for the 1991 regional contest. 2010 The 2010 Florida Association of Environmental Soil Scientists (FAESS) Hydric Soils Workshop (HSW) was held in Indian River County, FL, near Vero Beach. In the photo above, soil scientist Frank Watts (seated), USDA-NRCS (retired) and pedologist of AAA Soil Consultants, administers the soil texture demonstration, which is a part of the FAESS HSW's field demonstrations. Participants practiced their abilities to determine different soil textures. On the table shown above, textures for fine sand, loamy fine sand, fine sandy loam, sandy clay loam, and sandy clay are in the foreground, while the darker samples in the background include mucky mineral (mucky fine sand) and muck textures, both of which are hydric soil indicators. Soil texturing at a Hydric Soils Workshop. FAESS conducts the popular Hydric Soils Workshop annually in April. The workshop location rotates around Florida, as soil characteristics vary geographically. The HSWs are comprised of morning classroom presentations by soil science experts, including professional consultants, university professors, and environmental regulators. A guided soils field trip conducted by members of the FAESS in the afternoon allows participants to gain hands-on experience identifying hydric soils in the field. FAESS Hydric Soils Workshops are popular and are attended each year by environmental consultants, engineers, Department of Health personnel, university students, and others. Information and photo courtesy of FAESS.

Measuring nearshore variability in benthic environments: An acoustic approach

Hardbottom and sedimentary habitats in the nearshore are continually affected by natural and anthropogenic disturbances. Currently used monitoring practices rely on visual techniques, aerial and underwater photography, which are conducted on an annual basis. These practices do not allow for rigorous assessment of the effects of human-induced or natural events on the distribution and composition of these habitats. We investigated the use of an acoustic ground discrimination system (RoxAnn) to determine changes in benthic habitats in the nearshore area of northern Indian River County, FL where hardbottom outcrops occur. It was determined that this method was precise and repeatable when deployed in a highly variable surf zone environment. Multiple surveys assessed temporal and spatial changes in bottom types. Spatial distributions of several bottom types were identified: bare rock surfaces, Sabellarid worm reef, sponge covered rock, and rock covered with two dominant algal species. Short-term (weekly) changes in the distribution of sand coverage were detected during a relatively calm hydrodynamic period. At one site (R-15), there was an increase of 11% in sediments, which attributed to approximately 2 750 m2 of coverage; 2.1 km south (R-22) there was a 6% decrease in sediments in six days. The latter equates to a change of almost 1 500 m2 of available habitat. These results suggest that the current practice of annual surveying is limited for assessing the magnitude and impact of episodic disturbances on benthic habitats. Based on these data, acoustic ground discrimination systems provide an unbiased, technology-based data collection method to distinguish benthic habitats in the surf zone. Employing this method will benefit researchers and coastal resource managers.

Effect of selected marine and freshwater microalgae on development and survival of the mosquito Aedes aegypti

We isolated and identified strains of marine and freshwater planktonic and benthic microalgae from the vicinity of Indian River County, Florida (≈27.5°N, 80.34°W), cultivated them in batch culture, and examined their allelopathic activity against mosquito larvae. Additional algal material was obtained from Syracuse University and the University of Texas—Austin Algal Culture Collection. Mosquito larvae (Aedes aegypti (L.)) from colonies maintained at the Florida Medical Entomology Laboratory were challenged with the microalgae using log-growth phase and senescent-phase cultures. Appropriate controls (no algae) were used for each treatment. There were no significant differences in development time between treatments across all trials and a few significant treatment effects on development times, mortality, or mosquito size in the individual trials; however, there was a tendency for treatments with senescent microalgae to develop faster than controls with no algae. Effects consistent with algal toxicity included the two trials with Microcystis aeruginosa, where the larvae exposed to the strain-producing microcystin had significantly longer development times than the controls or those grown with the non-microcystin-producing strain, and the trial with the dinoflagellate Akashiwo sanguinea, where larvae exposed to this species had significantly higher mortality than the controls. No consistent patterns or differences between experimental and control treatments in the value of λ′, an estimate of the population finite rate of increase, were discernible from the data.

Diversification of West Nile virus in a subtropical region

BackgroundWest Nile virus (WNV) has spread across North, Central, and South America since its introduction in 1999. At the start of this spread, Florida was considered a potentially important area with regards to transmission due to its geographic, climatological, and demographic conditions. Curiously, the anticipated high levels of transmission or disease outbreaks have not been observed. As other studies have predicted that the lack of intense WNV transmission is not due to vector incompetence, we sought to evaluate the role of viral strain diversity in WNV transmission in Florida. Therefore, a phylogentic analysis was carried out on several isolates collected from three distinct locations in Florida.ResultsContrasting with a positive control collected in Indian River County, Florida during 2003 that contains the original NY99 genotype with valanine at amino acid 159 of the envelope region, all of the isolates collected in 2005 contain the WN02 genotype composed of a substation with alanine at that position indicating the window of introduction of the WN02 genotype occurred between 2003 and 2005. From the eight isolates collected in Duval, Indian River, and Manatee Counties; there is also a silent nucleotide substitution that differentiates the isolates collected on the Atlantic side of the state compared to the isolate collected on the Gulf side, which groups closer to isolates from other locations near the Gulf.ConclusionAs a whole, the Florida isolates contained numerous variable nucleotide and amino acid sites from the reference sequences, as well as each other; indicating greater nucleotide diversity within the Florida 2005 isolates than within other regions. Finally, a series of three amino acid substitutions surrounding a set of histidines located in the envelope coding region that hypothesized to play a role in conformational changes was found in the isolate collected in Indian River County, perhaps changing the antigenicity of the homodimer. Taken together, these findings expand our understanding of the temporal and spatial compartmentalization of West Nile virus subtypes within North America.

Using Hydrologic Conditions to Forecast the Risk of Focal and Epidemic Arboviral Transmission in Peninsular Florida

The accurate forecasting and tracking of arboviral transmission is becoming increasingly critical for the early recognition and management of arboviral epidemics. Meteorological factors, especially rainfall and temperature, drive arboviral epidemics, but monitoring rainfall and temperature alone is not predictive of increased levels of vector-borne disease transmission. In Florida, model simulations of water table depth (WTD) provide a measure of drought, and they have been shown to provide an accurate forecast of arboviral transmission. Here, we tracked WTD in two peninsular Florida regions where focal West Nile virus (family Flaviviridae, genus Flavivirus, WNV) transmission was reported during 2004 and 2005. We compared the resulting WTD profiles with historical WTD simulations for Indian River County (IRC), FL, where two peninsular Florida St. Louis encephalitis virus epidemics had their epicenters in 1977 and 1990. In both of the regions where focal WNV transmission was reported during 2004 and 2005, the local WTD profiles approached the 1977 and 1990 IRC WTD profiles; however, differences in the local temporal sequence of hydrologic conditions were observed. These differences seem in part to explain why the focal WNV transmission during 2004 and 2005 failed to reach epidemic levels in peninsular Florida. These findings suggest that hydrologic monitoring, specifically WTD, may help determine the geographic extent, timing, and intensity of WNV transmission. We speculate that a more precise sequence of drought and wetting, including a secondary summer drying and wetting cycle, as occurred in IRC during 1977 and 1990, may provide the optimal hydrologic conditions for the expansion of an arbovirus outbreak from focal to epidemic. This study documents that monitoring hydrologic conditions, along with vector, avian amplification host, and virus population data, increases our ability to track and predict significant levels of arboviral transmission.

Salary Stipend Targets Recruitment, Retention

Salary Stipend Targets Recruitment, Retention

Arbovirus Transmission by Culex nigripalpus in Florida, 2005

Understanding the transmission patterns of West Nile and St. Louis encephalitis viruses (family Flaviviridae, genus Flavivirus, WNV and SLEV) could result in an increased ability to predict transmission risk to humans. To examine transmission patterns between vector and host, we trapped mosquitoes in three Florida counties from June to November 2005 by using chicken-baited lard can mosquito traps. These traps were used to monitor for presence of WNV and SLEV in mosquitoes and subsequent transmission of these viruses to chickens. In total, 166,615 female mosquitoes were sorted into 4,009 pools based on species and bloodfed status, and they were tested for presence of WNV and SLEV. Sera from 209 chickens were tested for WNV and SLEV antibodies. We detected eight WNV-positive Culex nigripalpus Theobald mosquito pools; SLEV was not detected in any pools. Six positive pools were collected in August and September from Duval County, one pool in September from Manatee County, and one pool in November from Indian River County. Of the eight chickens potentially exposed to WNV, antibodies were detected in only one chicken, indicating a low rate of transmission relative to the observed mosquito infection rates. Low virus transmission rates relative to infection rates would suggest that using sentinel chicken seroconversion data as a means of arbovirus surveillance may underestimate the prevalence of WNV in the mosquito population. However, using mosquito infection rates may overestimate the risk of arboviral transmission. A variety of factors might account for the observed low level of transmission including a lack of viral dissemination in mosquito vectors.

Arbovirus transmission by Culex nigripalpus in Florida, 2005.

Understanding the transmission patterns of West Nile and St. Louis encephalitis viruses (family Flaviviridae, genus Flavivirus, WNV and SLEV) could result in an increased ability to predict transmission risk to humans. To examine transmission patterns between vector and host, we trapped mosquitoes in three Florida counties from June to November 2005 by using chicken-baited lard can mosquito traps. These traps were used to monitor for presence of WNV and SLEV in mosquitoes and subsequent transmission of these viruses to chickens. In total, 166,615 female mosquitoes were sorted into 4,009 pools based on species and bloodfed status, and they were tested for presence of WNV and SLEV. Sera from 209 chickens were tested for WNV and SLEV antibodies. We detected eight WNV-positive Culex nigripalpus Theobald mosquito pools; SLEV was not detected in any pools. Six positive pools were collected in August and September from Duval County, one pool in September from Manatee County, and one pool in November from Indian River County. Of the eight chickens potentially exposed to WNV, antibodies were detected in only one chicken, indicating a low rate of transmission relative to the observed mosquito infection rates. Low virus transmission rates relative to infection rates would suggest that using sentinel chicken seroconversion data as a means of arbovirus surveillance may underestimate the prevalence of WNV in the mosquito population. However, using mosquito infection rates may overestimate the risk of arboviral transmission. A variety of factors might account for the observed low level of transmission including a lack of viral dissemination in mosquito vectors.

First Record of Cuterebra fontinella (Diptera: Oestridae) Larvae Infesting a Florida Rat (Rodentia: Muridae)

The host relationships of Cuterebra spp. bot flies (D?ptera: Oestridae) are of interest from both the perspective of parasite/host coevolution (Col well et al. 2006; Slansky 2007a) and the context of these insects causing a type of myiasis (cuterebro sis) in cats, dogs, humans, and other mammals (Safdar et al. 2003; Slansky 2007b,c; 2008). Cute rebra spp. larvae typically parasitize either indig enous lagomorphs (rabbits and hares) or rodents (e.g., mice, rats and tree squirrels) in the Ameri cas (Sabrosky 1986; Slansky & Kenyon 2003), with each generally restricted to one or a few closely related host species. Occasionally they in fest other mammals ('atypical' hosts; Sabrosky 1986; Slansky & Huckabee 2006; Slansky 2007b,c; Slansky 2008). Whether the latter repre sent aberrant cases, as categorized by Sabrosky (1986), or reflect incipient broadening of the host spectrum of these flies, is uncertain. Thus, studies are required to help define these flies' host rela tionships. Here we describe an unusual case of an eastern woodrat, Neotoma floridana (Ord) (Ro dentia: Muridae), parasitized by larvae o? Cutere bra fontinella Clark, which typically infest mice. In late Apr 2007, a severely emaciated rat in Sebastian, Indian River county, Florida, was killed in a suburban area adjacent to a 0.3 ha plot of dense scrub, including Brazilian pepper (Schi nus terebinthifolius Raddi, palmetto (Sabal spp. and Serenoa repens (Bartr.) Small, oak (Quercus spp.) and pine (Pinus spp.). Upon the animal's death, 5 larvae emerged from its lower abdomen, leaving large holes that exposed the underlying muscle fascia. Four larvae were placed in a glass jar with vented lid containing moist sandy soil, and a thin layer of soil was sprinkled over them. The jar was kept in a shaded area outdoors for ap proximately 3 weeks, after which it was main tained indoors at approximately 21-24?C; 2 fe male flies eventually emerged, 1 in late Jun and the other in early Jul, 2007. Subsequently, they died and were pinned for preservation. One larva was preserved in isopropanol. These specimens are deposited in the Medical & Veterinary Insect Collection, Department of Entomology & Nema tology, at the University of Florida, Gainesville, as voucher specimens UF070501, UF070502 and UF070503, respectively. The first fly was photo graphed with a Nikon? model D200 digital cam era, and images of the larva were made with an Automontage? digital photomicroscopy system (Synchroscopy, Frederick, Maryland). The rat was tentatively identified as an eastern woodrat but the specimen was not retained. Another rat was therefore collected from the same population and confirmed to be N. floridana; it is deposited as voucher specimen UF 31368 in the mammal col lection of the Florida Museum of Natural History at the University of Florida, Gainesville. Based upon information in Sabrosky (1986), the flies (Fig. la,b) were determined to be C. fon tinella. The larva (Fig. lc) appears to have par tially pupariated. Some of the mostly flattened, exterior platelets are raised slightly and have multiple points (Fig. Id), a characteristic of third instars of rodent-infesting Cuterebra species; in contrast, lagomorph-infesting species have cone shaped spine-like platelets (Slansky & Huckabee 2006; Slansky 2007b). The lack of 2 button-like anterior spiracles typically extruded by Cuterebra spp. larvae during pupariation (Sabrosky 1986; Slansky & Kenyon 2003) indicates this process was incomplete. The pupal durations and dates of emergence for these specimens support records indicating that C. fontinella has 2 or more gener ations per year in the southeastern US (Sabrosky 1986; Durden 1995, 2008; Slansky 2006). This species apparently has not been reported previ ously from Indian River County, although there are records from other eastern counties north (Or ange and Volusia) and south (Broward and St. Lu cie) of this county (Slansky 2006). Only 2 published studies have reported Cutere bra spp. infesting N. floridana in Florida, and in neither was the species of Cuterebra identified (Johnson 1930; Worth 1950a). Outside Florida, only Cuterebra americana (Fabricius) has been reared from N. floridana (Sabrosky 1986; L. A. Durden, personal communication to F. S.). Thus, the case described here appears to be the first con firmed report o? a. Cuterebra species other than C. americana, and of C. fontinella, reared from N. floridana. This appears to be the first published, substantiated record for Florida of a Cuterebra species reared from any of the 3 indigenous rat species (N. floridana, the rice rat, Oryzomys palustris (Harlan) and the hispid cotton rat, Sig modon hispidus Say and Ord) or 2 non-indigenous

ISOLATION OF BACILLUS SPHAERICUS WITH IMPROVED EFFICACY AGAINST CULEX QUINQUEFASCIATUS

A Bacillus sphaericus highly toxic to 4th-stage Culex quinquefasciatus was isolated from sediment samples collected at Winter Beach marsh in Indian River County, Florida. This isolate, named WBM 1-1-13, showed significantly higher toxicity compared with strain 2297. WBM 1-1-13 is equivalent, though better initially, to the toxicity of strain 2362, the active ingredient of VectoLex. Furthermore, the Winter Beach marsh isolate produced more Bin per unit medium than strain 2362, which suggests that this new isolate could be useful for Culex control.