Mosquito Surveillance and Insecticide Resistance Monitoring Conducted by the Florida Keys Mosquito Control District, Monroe County, Florida, USA.

Mosquito control programs in the State of Florida are charged with protecting human and animal health, fostering economic development of the State, permitting enjoyment of the natural attractions in Florida, and improving the quality of life of citizens. Mosquito control programs must accomplish these tasks in such a manner as will protect the environment and terrestrial, marine, and freshwater ecosystems. The Florida Keys Mosquito Control District provides a science-based Integrated Pest Management mosquito control program to the residents of the Florida Keys, Monroe County, Florida. Operational decisions are based on surveillance of adult and immature mosquitoes. Mosquito populations are monitored by means of carbon dioxide-baited light traps BG Sentinel traps, truck traps, gravid traps, oviposition traps, and human landing rate counts. Larvae and pupae are monitored by inspections of natural and human-made immature habitats. Due to past and current reliance on chemical pesticides for control of mosquitoes, the District maintains a pesticide resistance detection program consisting of CDC bottle bioassays and larval bioassays, challenging local mosquito species with currently used adulticides and larvicides.

Characterization of Pyrethroid Resistance Mechanisms in Aedes aegypti from the Florida Keys.

The status of insecticide resistance in Aedes aegypti is of concern in areas where Aedes-borne arboviruses like chikungunya, dengue, and Zika occur. In recent years, outbreaks involving these arboviruses have occurred, for which vaccines do not exist; therefore, disease prevention is only through vector control and personal protection. Aedes aegypti are present on every inhabited island within the Florida Keys. The resistance status of Ae. aegypti in the Florida Keys was assessed to guide knowledge of the best choice of chemical for use during an outbreak. Mosquito eggs were collected using ovitraps placed on Key West, Stock Island, Vaca Key, Upper Matecumbe Key, Plantation Key, and Key Largo. Bottle bioassays were conducted at the Florida Keys Mosquito Control District using Biomist® 30+30 (Clarke Mosquito Control Products, Inc., Roselle, IL). Further bottle testing using malathion and permethrin occurred at the CDC, Fort Collins, CO, in addition to molecular and biochemical assays. Levels of resistance varied between islands with different underlying mechanisms present. Resistance was seen to Biomist® 30+30 but not to permethrin, indicating that piperonyl butoxide (PBO) or the inert ingredients may be involved in resistance. No study has been conducted to date examining the role of PBO in resistance. Key Largo was treated the most with adulticides and expressed the highest levels of alpha and beta esterases, oxidases, glutathione-S-transferases, and frequency of the V1016I knockdown mutation from all sites tested. Knowledge of localized resistance and underlying mechanisms helps in making rational decisions in selection of appropriate and effective insecticides.

Human Blood Feeding by Aedes aegypti (Diptera: Culicidae) in the Florida Keys and a Review of the Literature.

Aedes aegypti L. is considered to have a proclivity for feeding on human blood even when other hosts are available. However, few studies have demonstrated host use by this mosquito in the continental United States, where local transmission of dengue, Zika, and chikungunya viruses has been recently documented. This study investigated the bloodmeal sources of female Ae. aegypti in the subtropical city of Key West and the surrounding county in Florida with the goal of identifying preferred hosts. Blood-engorged Ae. aegypti mosquitoes were collected from BG Sentinel traps used as part of a routine surveillance program in the Florida Keys (Monroe County, Florida). Bloodmeal samples were analyzed using PCR assays, sequencing, and comparison with reference sequences in GenBank. Aedes aegypti females from Key West fed predominantly on humans (79.6%) and did not differ statistically from females collected from the rest of the Florida Keys (69.5%). Culex quinquefasciatus Say (Diptera: Culicidae), considered a host generalist, was collected and analyzed from the same sites for comparative purposes. Females of Cx. quinquefasciatus fed predominantly (70.7%) on birds and nonhuman mammals in the Florida Keys, corroborating the validity of molecular assay breadth and demonstrating that given the same group of available hosts Ae. aegypti selects humans. Our results indicated that Ae. aegypti has a high rate of human-biting in a subtropical area within the United States, supporting its role in recent local transmission of dengue and other viruses.

Florida Keys Mosquito Control District Comprehensive Hurricane Plan.

The hurricane plan developed by the Florida Keys Mosquito Control District and approved by vote of the Board of Commissioners is presented. The plan is intended to facilitate prompt resumption of services after a tropical cyclone (tropical storm or hurricane) and to give direction and instructions to District staff who evacuate before a storm makes landfall. Specific procedures are documented for before and after storms, including communication, preparation of buildings and vehicles, and evacuation. The need for food and water for staff immediately after a storm is specifically mentioned in the plan. The plan is composed of five main sections: general preparedness, Lower Keys procedures, Middle Keys procedures, Upper Keys procedures, and aerial operations procedures. Also included is a section covering satellite telephone operation and a list of telephone contacts for local government and law enforcement agencies. An addendum details the District's policy for compensation for public emergency response work so all employees are aware of how they will be paid during the storm recovery period.

Establishment of Aedes albopictus (Diptera: Culicidae) in the Florida Keys, 2001-2017.

The presence of Aedes albopictus (Skuse) was first reported in the Florida Keys in 1993. Despite extensive surveillance, the Florida Keys Mosquito Control District (FKMCD) only collected specimens occasionally on a few islands, some years finding no evidence of the invasive species. In 2013-2017, FKMCD witnessed a sudden increase in population size and geographic extent of Ae. albopictus. Samples of Ae. albopictus have now been identified on 30 different islands in the Florida Keys. Three islands in particular (Key Largo, Big Pine Key, and Stock Island) have produced multiple positive samples during at least 4 of the last 5 yr, suggesting establishment of the invasive species. FKMCD continues to monitor Ae. albopictus throughout the Keys and make extensive efforts to reduce population abundance and geographic extent of this disease vector.

A Large Scale Biorational Approach Using Bacillus thuringiensis israeliensis (Strain AM65-52) for Managing Aedes aegypti Populations to Prevent Dengue, Chikungunya and Zika Transmission.

BACKGROUND: Aedes aegypti is a container-inhabiting mosquito and a vector of dengue, chikungunya, and Zika viruses. In 2009 several cases of autochthonous dengue transmission were reported in Key West, Florida, USA prompting a comprehensive response to control A. aegypti. In Key West, larvae of this mosquito develop in containers around human habitations which can be numerous and labor intensive to find and treat. Aerial applications of larvicide covering large areas in a short time can be an efficient and economical method to control A. aegypti. Bacillus thuringiensis israelensis (Bti) is a bacterial larvicide which is highly target specific and appropriate for wide area spraying over urban areas, but to date, there are no studies that evaluate aerial spraying of Bti to control container mosquitoes like A. aegypti. METHODOLOGY: This paper examines the effectiveness of aerial larvicide applications using VectoBac® WG, a commercially available Bti formulation, for A. aegypti control in an urban setting in the USA. Droplet characteristics and spray drop deposition were evaluated in Key West, Florida, USA. The mortality of A. aegypti in containers placed under canopy in an urban environment was also evaluated. Efficacy of multiple larvicide applications on adult female A. aegypti population reduction was compared between an untreated control and treatment site. CONCLUSIONS: Droplet characteristics showed that small droplets can penetrate through dense canopy to reach small containers. VectoBac WG droplets reached small containers under heavy canopy in sufficient amounts to cause > 55% mortality on all application days and >90% mortality on 3 of 5 application days while controls had <5% mortality. Aerial applications of VectoBac WG caused significant decrease in adult female populations throughout the summer and during the 38th week (last application) the difference in adult female numbers between untreated and treated sites was >50%. Aerial larvicide applications using VectoBac WG can cover wide areas in a short period of time and can be effective in controlling A. aegypti and reducing A. aegypti-borne transmission in urban areas similar to Key West, Florida, USA.

Evaluating public housing residents for knowledge, attitudes, and practices following dengue prevention outreach in Key West, Florida.

BACKGROUND: In 2009-2010, 93 cases of dengue were identified in Key West, Florida. This was the first outbreak of autochthonous transmission of dengue in Florida since 1934. In response to this outbreak, a multifaceted public education outreach campaign was launched. The aim of this study is to compare dengue prevention knowledge, attitudes, perceptions, and prevention practices among residents of subsidized public housing to the general population in Key West and to assess whether there were barriers preventing effective outreach from reaching specific vulnerable populations. METHODS: A randomized population-based evaluation of knowledge, attitudes, and behaviors toward dengue prevention consisting of 521 separate household interviews was undertaken in July of 2011. A subset analysis was performed on interviews collected from 28 public housing units within four subsidized public housing complexes. Analysis was performed to determine whether knowledge, attitudes, and behaviors exhibited by public housing residents differed from the non-public housing study population. RESULTS: Public housing residents recalled fewer outreach materials (p=0.01) and were 3.4 times (95% confidence interval [CI] 1.4-8.3) more likely not to recall any outreach materials. Public housing residents were less likely to correctly identify how dengue transmission occurs (61% vs. 89%), where mosquitoes lay their eggs (54% vs. 85%), or to identify any signs or symptoms related to dengue (36% vs. 64%). Public housing residents were less likely to perform dengue prevention practices such as removing standing water or always using air conditioning. CONCLUSIONS: Examination of public housing residents identified an at-risk population that recalled less exposure to outreach materials and had less knowledge about dengue infection and prevention than the randomized study population. This provides public health systems the opportunity to target or modify future health messages and interventions to this group. Differences identified in the demographics of this population suggest that alternative methods or non-English materials may be required to reach desired outcomes.

Larviciding offshore islands reduces adulticidal treatment of populated areas adjacent to national wildlife refuges.

The Florida Keys Mosquito Control District has conducted larvicide missions on uninhabited offshore islands of the Great White Heron National Wildlife Refuge and the National Key Deer Refuge since 2003. The objective of these missions is to reduce the need to apply adulticides on nearby populated islands where private lands are interspersed with refuge lands that support a diverse assemblage of native butterflies and insect-pollinated plants on Big Pine Key, No Name Key, Little Torch Key, Middle Torch Key, and Big Torch Key (the Torch Keys). More than 800 visits were made to refuge islands by Florida Keys Mosquito Control District personnel; 334 aerial larvicide missions were flown. From 2003 to 2010, a marked reduction in adult mosquito numbers was seen on Big Pine Key, and to a lesser extent on No Name Key. Seasonal distribution of mosquitoes was not different, however. Number of aerial adulticide missions flown on Big Pine Key, No Name Key, and the Torch Keys was 2, 1, and 2 in 2003; 9, 10, and 7 in 2004; 4, 4, and 2 in 2005; 6, 6, and 7 in 2006; 1, 0, and 0 in 2007; 3, 2, and 4 in 2008; 4, 3, and 4 in 2009; and 1, 1, and 3 in 2010, respectively. This is a dramatic reduction from prior years; from 1998 to 2002, 57 aerial adulticide missions were flown on Big Pine Key, 45 missions were flown on No Name Key, and 38 on the Torch Keys. Larviciding is an important component of an integrated approach to mosquito management that seeks to reduce environmental impacts on the national wildlife refuges.

Mosquito fauna of wilderness islands within the National Key Deer Refuge and the Great White Heron National Wildlife Refuge, Monroe County, Florida.

Dry ice-baited light traps, counts of mosquitoes biting and landing on technicians, and larval surveillance were used to determine mosquito species abundance on Annette Key, Little Knockem-down Key, Little Pine Key, Raccoon Key, and the Water Keys, all of which are located offshore, within the National Key Deer Refuge and Great White Heron National Wildlife Refuge in Monroe County, FL. Due to the close proximity of these wilderness islands to the inhabited islands of the Florida Keys, it is important to understand the abundance and composition of the mosquitoes and the effects they may have on populations on inhabited islands. Thirty different species were collected during 2004-2008. Aedes taeniorhynchus, the black salt-marsh mosquito, was the most abundant mosquito species collected at all locations. Other mosquitoes collected in large numbers at all locations were Anopheles atropos, Culex bahamensis, Cx. nigripalpus, and Deinocerites cancer. Because these wilderness islands are difficult to traverse due to vegetative growth, the placement of mosquito traps close to the perimeter of the islands may influence assessment of the abundance and diversity of mosquito species collected on each island.

Epidemiology and genetic variability of human metapneumovirus during a 4-year-long study in Southeastern Brazil.

Epidemiological and molecular characteristics of human metapneumovirus (hMPV) were compared with human respiratory syncytial virus (hRSV) in infants and young children admitted for acute lower respiratory tract infections in a prospective study during four consecutive years in subtropical Brazil. GeneScan polymerase chain assays (GeneScan RT-PCR) were used to detect hMPV and hRSV in nasopharyngeal aspirates of 1,670 children during January 2003 to December 2006. hMPV and hRSV were detected, respectively, in 191 (11.4%) and in 702 (42%) of the children admitted with acute lower respiratory tract infections at the Sao Paulo University Hospital. Sequencing data of the hMPV F gene revealed that two groups of the virus, each divided into two subgroups, co-circulated during three consecutive years. It was also shown that a clear dominance of genotype B1 occurred during the years 2004 and 2005, followed by genotype A2 during 2006.

Surveillance of eight respiratory viruses in clinical samples of pediatric patients in southeast Brazil.

OBJECTIVE: Detection of the eight most common respiratory viruses: human respiratory syncytial virus (HRSV), influenza virus A and B (IA and IB), parainfluenza viruses 1, 2 and 3 (HPIV1, 2 and 3), adenovirus (Ad) and human metapneumovirus (HMPV), in order to establish the etiology of acute respiratory infections (ARIs) and the epidemiology of these viruses in young children seen at Hospital Universitário, Universidade de São Paulo, in São Paulo, Brazil, during 2003. METHODS: The epidemiological surveillance was conducted in all children younger than 5 years hospitalized at the Hospital for lower respiratory tract infections (LRTI) from January 1, 2003 to December 30, 2003. Nasal and throat samples were scanned for respiratory viruses by polymerase chain reaction and detected by the GeneScan assay. RESULTS: Of 336 samples collected from 336 patients, 187 (55.6%) were positive for at least one of the respiratory viruses studied. Of all the children, HRSV was identified in 24.1%, HMPV in 17.8%, HPIV3 in 8.3%, Ad in 6.8%, IA in 5%, HPIV1 in 0.6%, but no virus could be detected in 44.1%. Dual virus infections were detected in 7.1% of all samples (12.8% of positive samples). HPIV2 and IB were not detected in the present study. CONCLUSIONS: This study confirms that children younger than 5 years and particularly younger than 1 year have a high hospitalization rate due to HRSV, HMPV, HPIV, influenza and adenovirus. We were able to determine the etiology and epidemiology of most ARIs and trace the seasonal profile of the commonest respiratory viruses among young children.

Vigilância de oito vírus respiratórios em amostras clínicas de pacientes pediátricos no sudeste do Brasil / Surveillance of eight respiratory viruses in clinical samples of pediatric patients in Southeast Brazil

OBJETIVO: Detecção de oito vírus respiratórios mais comuns: vírus respiratório sincicial humano (VRSH), vírus influenza tipo A e B (IA e IB), vírus da parainfluenza 1, 2 e 3 (VPIH1, 2 e 3), adenovírus (Ad) e metapneumovírus humano (MPVH), a fim de estabelecer a etiologia das infecções respiratórias agudas (IRA) e a epidemiologia desses vírus em crianças pequenas atendidas no Hospital Universitário da Universidade de São Paulo, em São Paulo, Brasil, durante o ano de 2003. MÉTODOS: A vigilância epidemiológica foi realizada em todas as crianças menores de 5 anos hospitalizadas por causa de doenças do trato respiratório inferior (DTRI) entre 1º de janeiro de 2003 e 20 de dezembro de 2003, no hospital universitário. Amostras coletadas de nasofaringe foram analisadas quanto à presença de vírus respiratórios através da reação em cadeia da polimerase e detectadas pelo programa GeneScan. RESULTADOS: Das 336 amostras coletadas, 187 (55,6 por cento) foram positivas para pelo menos um dos vírus respiratórios estudados. De todas as crianças, o VRSH foi identificado em 24,1 por cento, o MPVH em 17,8 por cento, o VPIH3 em 8,3 por cento, o Ad em 6,8 por cento, o IA em 5 por cento, o VPIH1 em 0,6 por cento, sendo que nenhum vírus foi detectado em 44,1 por cento. Infecções virais duplas foram detectadas em 7,1 por cento de todas as amostras (12,8 por cento das amostras positivas). O VPIH2 e o IB não foram detectados no presente estudo. CONCLUSÕES: Este estudo confirma que as crianças menores de 5 anos, e especialmente aquelas menores de 1 ano, apresentam uma alta taxa de hospitalização devido aos seguintes vírus: VRSH, MPVH, VPIH, influenza e adenovírus. Foi possível determinar a etiologia e epidemiologia da maioria das IRAs e traçar o perfil de sazonalidade dos vírus respiratórios mais comuns entre as crianças pequenas.

OBJECTIVE: Detection of the eight most common respiratory viruses: Human respiratory syncytial virus (HRSV), influenza virus A and B (IA and IB), parainfluenza viruses 1, 2 and 3 (HPIV1, 2 and 3), adenovirus (Ad) and human metapneumovirus (HMPV), in order to establish the etiology of acute respiratory infections (ARIs) and the epidemiology of these viruses in young children seen at Hospital Universitário, Universidade de São Paulo, in São Paulo, Brazil, during 2003. METHODS: The epidemiological surveillance was conducted in all children younger than 5 years hospitalized at the Hospital for lower respiratory tract infections (LRTI) from January 1, 2003 to December 30, 2003. Nasal and throat samples were scanned for respiratory viruses by polymerase chain reaction and detected by the GeneScan assay. RESULTS: Of 336 samples collected from 336 patients, 187 (55.6 percent) were positive for at least one of the respiratory viruses studied. Of all the children, HRSV was identified in 24.1 percent, HMPV in 17.8 percent, HPIV3 in 8.3 percent, Ad in 6.8 percent, IA in 5 percent, HPIV1 in 0.6 percent, but no virus could be detected in 44.1 percent. Dual virus infections were detected in 7.1 percent of all samples (12.8 percent of positive samples). HPIV2 and IB were not detected in the present study. CONCLUSIONS: This study confirms that children younger than 5 years and particularly younger than 1 year have a high hospitalization rate due to HRSV, HMPV, HPIV, influenza and adenovirus. We were able to determine the etiology and epidemiology of most ARIs and trace the seasonal profile of the commonest respiratory viruses among young children.