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The frequency of moderate to heavy rainfall events is projected to change in response to global warming. Here we show that these hydrologic changes may have a profound effect on mosquito population dynamics and rates of mosquito-borne disease transmission. We develop a simple model, which treats the mosquito reproductive cycle as a phase oscillator that responds to rainfall frequency forcing. This model reproduces observed mosquito population dynamics and indicates that mosquito-borne disease transmission can be sensitive to rainfall frequency. These findings indicate that changes to the hydrologic cycle, in particular the frequency of moderate to heavy rainfall events, could have a profound effect on the transmission rates of some mosquito-borne diseases.

Eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) is a mosquito-borne pathogen found in eastern North America that causes severe disease in humans and horses. The mosquito Culiseta melanura (Coquillett) (Diptera: Culicidae) is the primary enzootic vector of EEEV throughout eastern North America while several mosquito species belonging to diverse genera serve as bridge vectors. The ecology of EEEV differs between northern and southern foci, with respect to phenology of outbreaks, important vertebrate hosts, and bridge vector species. Active transmission is limited to roughly half of the year in northern foci (New York, New Hampshire, Massachusetts, Connecticut), while year-round transmission occurs in the southeastern region (particularly Florida). Multiple phylogenetic analyses indicate that EEEV strains circulating in northern foci are likely transported from southern foci by migrating birds. Bird species that overwinter or migrate through Florida, are bitten by Cs. melanura in late spring, and arrive at northern breeding grounds in May are the most likely candidates to disperse EEEV northward. Available data indicate that common yellowthroat and green heron satisfy these criteria and could serve as virus dispersers. Understanding the factors that drive the phenology of Cs. melanura reproduction in the south and the timing of avian migration from southern foci could provide insight into how confluence of these biological phenomena shapes outbreaks of EEE throughout its range. This information could be used to develop models predicting the likelihood of outbreaks in a given year, allowing vector control districts to more efficiently marshal resources necessary to protect their stakeholders.

The mosquito Culiseta melanura (Coquillett) is the primary enzootic vector of eastern equine encephalitis virus (EEEV), a zoonotic Alphavirus endemic to eastern North America. In its northern range, Cs. melanura is considered a strict avian biter, transmitting EEEV among susceptible birds in a cycle of enzootic amplification. In its southern range, however, Cs. melanura is more general in host use, feeding heavily upon birds but also reptiles and mammals. The goal of this study was to better understand how host use of Cs. melanura changes throughout the year in Florida, where year-round EEEV transmission is observed. Mosquitoes were sampled in 2018 from nine sites across three central Florida counties. In total, 213 Cs. melanura bloodmeals were identified by PCR consisting of 39 species of birds, reptiles, and mammals. Avian bloodmeals were prominent throughout the year (range = 30–85%), and songbirds were a large portion of identified bloodmeals (37.1%). Reptiles surpassed birds only in spring (April–June), and brown anole (Anolis sagrei Duméril and Bibron, 1837 [Reptilia: Dactyloidae]) was the most commonly detected single host species (22.1% overall). Mammalian bloodmeals were mainly observed in summer, with humans being the most fed on mammal (12.7% overall). This study reveals that in southern foci of EEEV transmission, Cs. melanura host use varies throughout the year with reptiles providing the majority of blood meals in spring (51.3%), and birds are fed on more than other host groups during all other seasons (50.6–70.1%). In addition, feeding on mammals increases during summer months, which may implicate Cs. melanura in epizootic transmission in Florida.

Richard Floyd Darsie, Jr. (1915-2014) is the 2015 American Mosquito Control Association Memorial Lecture Honoree. He was one of the greatest mosquito taxonomists of the 20th century and died peacefully on April 10, 2014, in Grove City, PA, at the age of 99 after a professional career that spanned eight decades. Dick's broad areas of interest and training made him a versatile scientist, teacher, and researcher. His intense interest in adult and immature mosquito morphology and taxonomy, as well as mosquito distribution and bionomics, started early in his career at two early academic postings: Franklin and Marshall College (1949-54) and the University of Delaware (1954-62). Dick would take his mosquito interests with him to postings and research projects around the world: Nepal, the Philippines, Atlanta, El Salvador, Guatemala, Fort Collins, South Carolina, Argentina, and Florida. His travels and studies would make him an international expert on mosquito taxonomy. Dick's legacy lives on in the hundreds of students from across the globe who learned mosquito identification skills from this world-renowned mosquito taxonomist. All will proudly profess that, \"I learned mosquito identification from Dr. Darsie.\" And that is all that is needed to prove one's credentials in the field, learning the art from the best there is.

Richard Floyd Darsie, Jr. (1915-2014) is the 2015 American Mosquito Control Association Memorial Lecture Honoree. He was one of the greatest mosquito taxonomists of the 20th century and died peacefully on April 10, 2014, in Grove City, PA, at the age of 99 after a professional career that spanned eight decades. Dick's broad areas of interest and training made him a versatile scientist, teacher, and researcher. His intense interest in adult and immature mosquito morphology and taxonomy, as well as mosquito distribution and bionomics, started early in his career at two early academic postings: Franklin and Marshall College (1949-54) and the University of Delaware (1954-62). Dick would take his mosquito interests with him to postings and research projects around the world: Nepal, the Philippines, Atlanta, El Salvador, Guatemala, Fort Collins, South Carolina, Argentina, and Florida. His travels and studies would make him an international expert on mosquito taxonomy. Dick's legacy lives on in the hundreds of students from across the globe who learned mosquito identification skills from this world-renowned mosquito taxonomist. All will proudly profess that, \"I learned mosquito identification from Dr. Darsie.\" And that is all that is needed to prove one's credentials in the field, learning the art from the best there is.

Richard Floyd Darsie, Jr. (1915–2014) is the 2015 American Mosquito Control Association Memorial Lecture Honoree. He was one of the greatest mosquito taxonomists of the 20th century and died peacefully on April 10, 2014, in Grove City, PA, at the age of 99 after a professional career that spanned eight decades. Dick’s broad areas of interest and training made him a versatile scientist, teacher, and researcher. His intense interest in adult and immature mosquito morphology and taxonomy, as well as mosquito distribution and bionomics, started early in his career at two early academic postings: Franklin and Marshall College (1949–54) and the University of Delaware (1954–62). Dick would take his mosquito interests with him to postings and research projects around the world: Nepal, the Philippines, Atlanta, El Salvador, Guatemala, Fort Collins, South Carolina, Argentina, and Florida. His travels and studies would make him an international expert on mosquito taxonomy. Dick’s legacy lives on in the hundreds of students from across the globe who learned mosquito identification skills from this world-renowned mosquito taxonomist. All will proudly profess that, “I learned mosquito identification from Dr. Darsie.” And that is all that is needed to prove one’s credentials in the field, learning the art from the best there is.

Richard Floyd Darsie, Jr, one of the greatest mosquito taxonomists of the 20th century, died peacefully on Apr 10, 2014, in Grove City, PA, at the age of 99 after a professional career that spanned 8 decades. Dick was born in Scottdale, PA, on Jan 28, 1915. He graduated from Scottdale High School in 1932. In 1937 he was awarded a B A degree in biology from Bethany College in West Virginia. From 1937 to 1941, he attended the University of Pittsburgh, where he received his M S degree in zoology. Dick served in the US Air Force during World War II from 1941 through 1945, after which he resumed his studies at Cornell University, where he received a Ph D in medical entomology in 1949.

We examine the relationship between hydrologic variability and the incidence of human disease associated with West Nile virus (WNV; family Flaviviridae, genus Flavivirus) infection (hereafter termed “human WN cases”) in Colorado from 2002 to 2007. We find that local hydrologic conditions, as simulated by the Mosaic hydrology model, are associated with differences in human WN cases. In Colorado’s eastern plains, wetter spring conditions and drier summer conditions predict human WN cases. In Colorado’s western mountains, drier spring and summer conditions weakly predict human WN cases. These findings support two working hypotheses: (1) wet spring conditions increase the abundance of Culex tarsalis vectors in the plains, and (2) dry summer conditions, and respondent irrigational practices during such droughts, favor Cx. pipiens and Cx. tarsalis abundance throughout Colorado. Both of these processes potentially increase the local vector-to-host ratio, favoring WNV amplification among competent avian hosts and bridging to humans.

St. Louis encephalitis virus was first identified as the cause of human disease in North America after a large urban epidemic in St. Louis, Missouri, during the summer of 1933. Since then, numerous outbreaks of St. Louis encephalitis have occurred throughout the continent. In south Florida, a 1990 epidemic lasted from August 1990 through January 1991 and resulted in 226 clinical cases and 11 deaths in 28 counties. This epidemic severely disrupted normal activities throughout the southern half of the state for 5 months and adversely impacted tourism in the affected region. The accurate forecasting of mosquito-borne arboviral epidemics will help minimize their impact on urban and rural population centers. Epidemic predictability would help focus control efforts and public education about epidemic risks, transmision patterns, and elements of personal protection that reduce the probability of arboviral infection. Research associated with arboviral outbreaks has provided an understanding of the strengths and weaknesses associated with epidemic prediction. The purpose of this paper is to review lessons from past arboviral epidemics and determine how these observations might aid our ability to predict and respond to future outbreaks.

Fecundity of mosquitoes can vary with many factors and can have a strong effect on population growth. This study reports the effects of body size, blood meal size, and age on the reproductive output of nulliparous Culex quinquefasciatus, a vector of arboviruses and other pathogens. Mated adult female mosquitoes from a colony were reared under standard conditions and fed on chickens at different ages post-eclosion. Blood meal size and wing length were recorded, as well as the number of eggs in the first-cycle egg raft. Each of these factors had a significant influence on fecundity considered in a simple regression context. Multiple regression analysis revealed a significant interaction effect between age and body size on fecundity. Up to 13 days of age, fecundity was positively correlated with body size, but in mosquitoes older than 13 days, this relationship was not significantly different from zero. These results are discussed in terms of the known physiology of this and other species.