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Full-Text Articles in Life Sciences

Vector Competence Of Northern California Mosquitoes For Dirofilaria Immitis (Spirurida: Onchocercidae), Rebekah Lynn Dian Jan 2018

Vector Competence Of Northern California Mosquitoes For Dirofilaria Immitis (Spirurida: Onchocercidae), Rebekah Lynn Dian

University of the Pacific Theses and Dissertations

Dirofilaria immitis, commonly known as dog heartworm, is a dangerous filarial nematode that is transmitted by a mosquito vector. Although this parasite is historically localized to regions closer to the equator, the last few decades have experienced an increase in the amount of dog heartworm cases in Northern California, most notably in Lake and San Joaquin Counties. The primary vector of D. immitis in Northern California is Aedes sierrensis, but it is not prevalent enough in some counties to explain the increase in infections. Because of this, more prevalent and abundant species should be assessed for their ability to transmit ...


An Evaluation Of Population Differentiation In Culex Tarsalis In Montana Using Coi Sequences, Jake Fiocchi Apr 2016

An Evaluation Of Population Differentiation In Culex Tarsalis In Montana Using Coi Sequences, Jake Fiocchi

Life and Environmental Sciences Undergraduate Theses

The Infectious Disease Ecology project at Carroll College has established protocols to successfully detect West Nile virus in Culex tarsalis, a species of mosquito that acts as a vector for this disease. The detection data combined with ecological factors have been used to produce a risk model capable of predicting where West Nile positive specimens will be detected annually. This specific project aimed to determine the relatedness of C. tarsalis from various regions across the state of Montana as this knowledge could aid in determining how West Nile virus infections may spread across the state. Cytochrome c oxidase I (COI ...


Comparison Of West Nile Virus Infection Rates In Culex Tarsalis And Exposure Rate Of Horses In Montana Using Rt-Pcr And Elisa, Sarah Fitzpatrick Apr 2015

Comparison Of West Nile Virus Infection Rates In Culex Tarsalis And Exposure Rate Of Horses In Montana Using Rt-Pcr And Elisa, Sarah Fitzpatrick

Life and Environmental Sciences Undergraduate Theses

Horses are more susceptible to West Nile virus (WNV) than human beings. In addition, for many ranchers in Montana, horses are their livelihood. In Montana, the only risk assessment tool for WNV is mosquito surveying. Testing horses across the state for WNV may contribute to a better estimate of high-risk areas. Also, since the numbers of human and horse cases are similar on a yearly basis, testing horses may predict the human risk. In this study, Culex tarsalis infection rates were compared with horse exposure rates in Montana. Mosquitos were collected from 46 sites on a weekly or biweekly basis ...


Rt-Pcr Survey Of Mosquitos In Montana, North Dakota, & South Dakota For The Presence Of Cache Valley Virus, Paige Esposito Apr 2013

Rt-Pcr Survey Of Mosquitos In Montana, North Dakota, & South Dakota For The Presence Of Cache Valley Virus, Paige Esposito

Life and Environmental Sciences Undergraduate Theses

In order to contribute to knowledge of Cache Valley Virus, a virus that causes ovine fetal malformations and stillbirths, this study conducted a survey of six mosquito species in three Northwestern states to determine the primary vector of the virus. Total RNA was extracted from mosquito samples and subjected to reverse transcription PCR to determine if viral RNA was present. Of the 369 samples tested, none tested positive for viral RNA. This outcome suggests either that the virus 1) is not present, 2) may be present at low levels or 3) may be carried by another insect. An increase in ...


Blood-Feeding Behavior Of Culex Tarsalis At Medicine Lake National Wildlife Refuge, Montana, Maxwell Bernt Apr 2013

Blood-Feeding Behavior Of Culex Tarsalis At Medicine Lake National Wildlife Refuge, Montana, Maxwell Bernt

Life and Environmental Sciences Undergraduate Theses

It is known that the ornithophillic mosquito, Culex tarsalis is the primary vector of West Nile Virus (WNV) in Montana. An analysis of this mosquito’s blood feeding behavior allows researchers to identify preferred hosts and to determine the rate at which this species parasitizes humans and other tangential hosts. Additionally, an understanding of blood feeding behavior allows an assessment of WNV risk based on the regional availability of preferred hosts and the hosts’ competency in viral amplification. In this study, blood engorged Cx. tarsalis were captured at Medicine Lake National Wildlife Refuge over three one-week periods spaced through early ...


Infection Rate Of West Nile Virus In Culex Tarsalis At Medicine Lake Wildlife Refuge And Ninepipe Wildlife Refuge In 2012, Graham Unis Apr 2013

Infection Rate Of West Nile Virus In Culex Tarsalis At Medicine Lake Wildlife Refuge And Ninepipe Wildlife Refuge In 2012, Graham Unis

Life and Environmental Sciences Undergraduate Theses

This study focused on the infection rate of West Nile virus of Culex tarsalis populations at Medicine Lake Wildlife Refuge (MLWR) and Ninepipe Wildlife Refuge (NWR). My research was done in order to determine if there was a statistical difference in the infection rate between NWR and MLWR via a bias corrected ML estimate. These locations were chosen because they were ideal locations for West Nile virus (WNV) and in the case of MLWR, past positive C. tarsalis pools. My study involved trapping mosquitoes, sorting out the C. tarsalis, and isolating WNV from mosquito homogenate. Once C. tarsalis had been ...


Microsatellite Analysis Of Gene Flow Between Culex Tarsalis Populations Connected By Irrigation In Yellowstone County, Montana, Mattie Casey Apr 2013

Microsatellite Analysis Of Gene Flow Between Culex Tarsalis Populations Connected By Irrigation In Yellowstone County, Montana, Mattie Casey

Life and Environmental Sciences Undergraduate Theses

The purpose of this study was to determine whether population connectivity by irrigation enhances gene flow between Culex tarsalis populations in the state of Montana. Four populations of Cx. tarsalis were collected along the Yellowstone and Bighorn rivers and allele frequencies obtained from PCR amplification of four microsatellite loci, visualized using the QIAxcel Advanced System, were used to assess the genetic structure of the populations. Results of the four loci indicate lower pairwise FST values between only two of three populations connected through waterway, which suggests a disparity in the data. If the genetic similarity between these populations reflects rates ...


The Spatial Games: Investigating The Spatial Distribution Of Anax And Select Prey As A Function Of Predator-Prey Interactions, Shane Elizabeth Johnson, Nene Kumashe Ugbah Jun 2012

The Spatial Games: Investigating The Spatial Distribution Of Anax And Select Prey As A Function Of Predator-Prey Interactions, Shane Elizabeth Johnson, Nene Kumashe Ugbah

Biological Sciences

Our study investigated the spatial distribution and movement behavior of predatory dragonfly larvae (Anax) and of two prey types: mosquito larvae and amphipods. Predator-prey interactions have important consequences for the population dynamics of both predator and prey groups and these interactions can shape community structure. We measured behavior of each prey type in the presence of the Anax predator and the behavior of the predator in the presence of these alternative prey types. Observations were made in five-gallon aquaria where a grid pattern allowed us to track the number of moves made by individuals. We compiled data from ten, one ...


Investigation Of West Nile Virus Infection Rates In Cx. Tarsalis At Medicine Lake Wildlife Refuge And Ninepipe Wildlife Refuge 2011, Joseph Maricelli Apr 2012

Investigation Of West Nile Virus Infection Rates In Cx. Tarsalis At Medicine Lake Wildlife Refuge And Ninepipe Wildlife Refuge 2011, Joseph Maricelli

Life and Environmental Sciences Undergraduate Theses

This study focused on the infection rate of West Nile virus in two Culex tarsalis mosquito populations in Montana. Medicine Lake Wildlife Refuge (MLWR) and Ninepipe Wildlife Refuge (NWR) Cx. tarsalis populations were chosen due to the variance in past viral incidence. Viral incidence at MLWR was thought to be higher due to higher infection rate in the Cx. tarsalis population possibly from favorable environmental factors. This study suggests, however, that high viral incidence may be a result of high Cx. tarsalis population as a proportion of the total mosquito population. Samples were homogenized and purified for RNA using a ...


Mapping The Abundance Of Culex Tarsalis To Environmental Variables In Montana, Benjamin Mcisaac Apr 2012

Mapping The Abundance Of Culex Tarsalis To Environmental Variables In Montana, Benjamin Mcisaac

Life and Environmental Sciences Undergraduate Theses

In Montana, West Nile Virus (WNV) was first recorded in 2002, and by 2003 there were 222 reported cases statewide. Currently, WNV still causes high fever, vomiting, muscle weakness, convulsions and paralysis in over 1,000 Americans each year. The primary vector of WNV differs spatially across the United States, with Culex pipiens as the primary vector in the east and Culex tarsalis contributing to the majority of human cases west of the Mississippi River. Different primary vectors suggest that geographical barriers of Cx. pipiens and Cx. tarsalis may be related to ecological factors. In the present study, mosquitoes were ...


Microsatellite Analysis Comparing The Genetic Variation Of Culex Tarsalis Populations Across Montana, Kellie O'Rourke Apr 2012

Microsatellite Analysis Comparing The Genetic Variation Of Culex Tarsalis Populations Across Montana, Kellie O'Rourke

Life and Environmental Sciences Undergraduate Theses

West Nile Virus (WNV), first detected in Montana in 2002, is transmitted by the mosquito Culex tarsalis in Montana. The purpose of the WNV project at Carroll College is to produce an infection risk assessment map for the state of Montana, created by determining the factors that affect the prevalence of the virus across the state. The objective of this specific study is to add one layer to the risk assessment map by using microsatellite analysis to compare the variation of genetic structure of differing populations of Cx. tarsalis across Montana. I hypothesized that the genetic differences (as measured by ...


Spatial Risk Assessment Of West Nile Virus In Montana Based Upon Temperature Effects On Cx. Tarsalis, Brian Murphy Apr 2012

Spatial Risk Assessment Of West Nile Virus In Montana Based Upon Temperature Effects On Cx. Tarsalis, Brian Murphy

Life and Environmental Sciences Undergraduate Theses

Spatial and seasonal West Nile virus (WNV) transmission risk was assessed throughout Montana with Geographic Information System (GIS) models based on the temperature threshold below which virus development will not proceed in Cx. tarsalis. The model used maximum, minimum, and average daily temperature data; a degree day modeling derivation that produced West Nile virus development units (WDU); and varying time-scales throughout June, July, August, and September. A temperature of 12.6 °C maintained for 107.7 degree days (dd) was utilized as the point of zero virus development and was based on the extrinsic incubation period (EIP) or the average ...


Birds As Reservoir Hosts For West Nile Virus In Montana, Victoria Dettman Apr 2012

Birds As Reservoir Hosts For West Nile Virus In Montana, Victoria Dettman

Life and Environmental Sciences Undergraduate Theses

West Nile virus (WNV) was first observed in the United States on the east coast in 1999. WNV is an arbovirus, meaning that it is stored in the tissues of arthropods and is then transmitted via a bite to vertebrates who become infected. Birds are vertebrates, and they then serve as vector reservoir hosts for the virus. They can transmit the virus to other vertebrates as well as back to arthropods. It was through birds that WNV quickly spread across the country, and we need to evaluate which birds are likely to transmit the virus and what living conditions they ...


Species Identification Of Ovine-Feeding Mosquitoes In Southwestern Montana, Whitney Miller Apr 2012

Species Identification Of Ovine-Feeding Mosquitoes In Southwestern Montana, Whitney Miller

Life and Environmental Sciences Undergraduate Theses

In order to contribute to research on Cache Valley Virus, an ovine virus that leads to fetus malformations and abortion, this study investigated the specific species of mosquitoes that blood feed on domestic sheep. Nine sheep were separated into three groups and were contained in a constructed trap one night per week for seven weeks (July-August 2011) in a rural area in southwestern Montana. Mosquitoes that entered the sheep-baited trap during the evening were then collected for species identification and bloodfed status the following morning. This study also examined the effectiveness of two different insecticide treatments. The three groups of ...


Dispersal, Gene Flow, And Adaptive Evolution During Invasion: Testing Range-Limit Theory With The Asian Tiger Mosquito, Kimberly Medley Jan 2012

Dispersal, Gene Flow, And Adaptive Evolution During Invasion: Testing Range-Limit Theory With The Asian Tiger Mosquito, Kimberly Medley

Electronic Theses and Dissertations, 2004-2019

Understanding the factors that make non-native species successful invaders is an important step towards mitigating spread. At the same time, species invasions can serve as natural experiments to test range-limit theory. Range-limit theory postulates declines in local abundance (abundant center model) and genetic diversity (central-peripheral hypothesis) towards range edges because of underlying environmental gradients. Such declines constrain adaptation to marginal habitats via gene swamping. However, broader evolutionary theory predicts intermediate rates of immigration into range-edge populations can relieve genetic drift and improve adaptive potential. I tested hypotheses generated from theory while illuminating aspects affecting of the invasion of the Asian ...


Influence Of Detritus Levels And Organic Pollution On Interspecific Resource Competition, Oviposition Behavior, And Larval Survival Of Two Tire-Inhabiting Mosquito Species (Diptera: Culicidae), David Wayne Allgood Dec 2011

Influence Of Detritus Levels And Organic Pollution On Interspecific Resource Competition, Oviposition Behavior, And Larval Survival Of Two Tire-Inhabiting Mosquito Species (Diptera: Culicidae), David Wayne Allgood

Master's Theses

Mosquitoes (Diptera: Culicidae) are vectors of disease in the adult stage, but understanding the factors affecting distributions of the immature stages is important to the understanding and control of adult populations. Discarded automobile tires comprise important larval mosquito habitats. The Asian tiger mosquito (Aedes albopictus) and the southern house mosquito (Culex quinquefasciatus) are two medically important species commonly found in tires, but factors affecting their larval distributions in tires have not been studied, nor have their interspecific interactions. I investigated the effects of chemicals associated with organic pollution on oviposition preferences and larval survival of both species, and the effects ...


Influence Of Agricultural Stream Habitat Alterations On Mosquitoes And Amphibians: Patterns, Processes, And Predictions, Julia Sonn May 2011

Influence Of Agricultural Stream Habitat Alterations On Mosquitoes And Amphibians: Patterns, Processes, And Predictions, Julia Sonn

Biology Theses

Changes to stream structure, riparian habitat, and water quality can alter ecosystem dynamics, resulting in an increase in mosquitoes, while weakening populations of amphibians. Therefore, it is necessary to understand how these components are affected by agricultural practices so that mosquito populations can be controlled and aquatic organisms can be protected. In this study, I examined changes in stream structure by measuring geomorphology at three riparian habitats that were anthropogenically impacted to varying degrees. I also compared water quality between the habitats. Mosquitoes and amphibians were surveyed at each riparian habitat, identified to species, and abundances were compared. Stream structure ...


Distribution Of Bird Reservoir Hosts For West Nile Virus In Montana, Billy Mcelroy Apr 2011

Distribution Of Bird Reservoir Hosts For West Nile Virus In Montana, Billy Mcelroy

Life and Environmental Sciences Undergraduate Theses

West Nile virus (WNv) is an arthropod-borne flavivirus that was first detected in the United States in 1999. By 2004 it had spread to 48 states and, to date, it has been the source of greater than 29,000 cases of human infection. WNv is maintained through an avian-mosquito transmission cycle, with birds serving as the primary vertebrate hosts for the amplification of the virus. Previous studies have shown Passeriform birds to be some of the most virulent competent hosts for the virus, producing adequate viremia counts for continuation of the transmission cycle. Associations were analyzed between mosquito populations and ...


West Nile Virus Presence And Blood-Feeding Behavior Of Culex Tarsalis In Wildlife Refuges And Management Areas In Montana, Kellie Kalbfleisch Apr 2011

West Nile Virus Presence And Blood-Feeding Behavior Of Culex Tarsalis In Wildlife Refuges And Management Areas In Montana, Kellie Kalbfleisch

Life and Environmental Sciences Undergraduate Theses

West Nile virus (WNV) has been documented across the state of Montana since 2002. Humans, other mammals, and birds have been affected by this virus in a heterogeneous manner throughout the state. Correlating the feeding patterns of Culex tarsalis, the principal WNV vector in the Western United States, with the presence of virus at Nine Pipe, Freezeout, Benton, and Bowdoin wildlife refuges and management areas allowed for analysis of the link between competent avian hosts and the presence of WNV. Further, identification of avian species present in Cx. tarsalis blood-meals allowed for the analysis of the correlation between relative abundance ...


Preliminary Analysis Of Population Differentiation Of Culex Tarsalis In Montana Using Microsatellites, Meghan Mckeown Apr 2011

Preliminary Analysis Of Population Differentiation Of Culex Tarsalis In Montana Using Microsatellites, Meghan Mckeown

Life and Environmental Sciences Undergraduate Theses

West Nile virus, an arbovirus classified in the genus Flaviviridae, presents a serious threat to humans and horses in Montana. The virus, first isolated in the West Nile district of Uganda in 1937, spread rapidly across the United States after its initial introduction to New York in 1999. In 2003 there were 222 human cases of West Nile in Montana. The overarching goal of the Carroll College West Nile virus study is to create a risk assessment map for the state of Montana. This will bring better awareness to the risk of West Nile infection based on geographic location and ...


Detection Of West Nile Virus In Mosquitoes Of Montana Through Rt-Pcr And Taqman Assays And Correlation To Reservoir Competent Avian Populations, Katie Semmens Apr 2010

Detection Of West Nile Virus In Mosquitoes Of Montana Through Rt-Pcr And Taqman Assays And Correlation To Reservoir Competent Avian Populations, Katie Semmens

Life and Environmental Sciences Undergraduate Theses

First emerging in the United States in 1999, and Montana in 2002, West Nile Virus (WNV) has had a significant impact on human and avian populations. Due to this significance, a greater understanding of the factors affecting the prevalence of WNV is necessary. Mosquitoes were collected from 27 locations across the state of Montana throughout the summer of 2009. RT-PCR and TaqMan assays were used to identify positive pools of mosquitoes, with three locations testing positive. As avian species serve as a reservoir for the virus, it is hypothesized that locations testing positive for WNV should have a greater presence ...


Development Of A Statewide Model Of Culex Tarsalis Habitat Suitability Using Gis, Jason Larsen Apr 2010

Development Of A Statewide Model Of Culex Tarsalis Habitat Suitability Using Gis, Jason Larsen

Life and Environmental Sciences Undergraduate Theses

My study combines the use of the maximum entropy approach to species habitat prediction with the need for a West Nile Virus (WNV) infection risk model for the state of Montana to produce a statewide null model of Culex tarsalis habitat to be used as the basis for a future infection risk model. My study assumes that C. tarsalis is the primary vector for WNV in Montana, and that MAXENT software can reliably generate a habitat suitability model for C. tarsalis throughout Montana using presence only data. I successfully generated a statistically sound, statewide model of C. tarsalis habitat using ...


Using Microsatellite Loci To Analyze Genetic Variation Of Culex Tarsalis Within Montana, Jeffery Bank Apr 2010

Using Microsatellite Loci To Analyze Genetic Variation Of Culex Tarsalis Within Montana, Jeffery Bank

Life and Environmental Sciences Undergraduate Theses

West Nile Virus (WNV) first arrived in the United States in 1999 and by 2002 was detected in Montana. The main bridge vector of WNV in Montana is the mosquito species Culex tarsalis. We are using geographic information system (GIS), molecular tools and landscape modeling techniques to develop a landscape-scale model of WNV infection risk for the state of Montana. The goals of this specific study were to identify microsatellite loci useful for characterizing the population genetic structure of C. tarsalis across Montana, and, utilizing this population genetic data, to infer migration (gene flow) patterns of mosquitoes across the state ...