Abstracts 751-1000
Total Page：16
File Type：pdf, Size：1020Kb
226 749 Trichprosophon); South American Phlebotomine Sand flies (include male and female keys of genera, subgenera, and vector species of Dampomyia, HOST SELECTION, DEFENSIVE BEHAVIORS AND FEEDING Evandromyia, Helcocrytomyia, Lutzomyia, Nyssomyia, Pintomyia, SUCCESS OF CULEX QUINQEFASCIATUS IN EXPERIMENTAL Psathyromyia, Psychodopygus, Sciopemyia, Trichophoromyia, Verrucarum TRIALS Group). Diagnostic characters, updated taxonomy and related information of new vector identification tools are noted and discussed. Joseph R. McMillan1, Paula L. Marcet2, Uriel Kitron1, Gonzalo M. Vazquez-Prokopec1 751 1Emory University, Atlanta, GA, United States, 2Centers for Disease Control and Prevention, Atlanta, GA, United States SRPN2 DEPLETION REDUCES MOSQUITO FITNESS AND Studies describing common blood sources of field collected mosquitoes BITING FREQUENCY are inconsistent in their description of the host selection behavior of KaraJo Sprigg1, Andrew F. Read2, Kristin Michel1 Culex quinquefasciatus. Host selection is an important determinant of 1Kansas State University, Manhattan, KS, United States, 2Pennsylvania State pathogen transmission, and this knowledge gap in mosquito behavior is University, University Park, PA, United States limiting our understanding of vector-host contacts and the importance of reservoir hosts in West Nile virus (WNV) transmission. We conducted The mosquito’s immune system is at the vector-pathogen interface and host-choice experiments under semi-natural conditions to quantify host largely determines susceptibility. One consequence of its manipulation can feeding preference by Cx. quinquefasciatus mosquitoes when presented be the reduction in vectorial capacity. Therefore, the mosquito immune with an array of common passerine hosts: Northern Cardinals, American system provides potential targets for novel intervention strategies aimed to Robins, Blue Jays, Brown Thrashers, and Gray Catbirds. The experimental reduce vector-borne disease burden. Melanization is a powerful immune design consisted of: 1) a 1.5m x 0.75m x 0.75m enclosure inside of response in arthropods that leads to encapsulation and killing of invading which two bird cages were placed, 2) 30 recently emerged female Cx. pathogens. This process renders some mosquito species partially or quinquefasciatus originating from wild eggs, and 3) an infra-red camera completely resistant to infection with pathogens of global public health recording system. We performed 12 two-bird choice experiments in which significance. One of its rate-limiting steps of melanization is the activation we calculated the feeding index for each potential host and tested the of prophenoloxidase (PPO), which is controlled by an extracellular null hypothesis of random host selection. We also quantified the number proteinase cascade and serpin inhibitors. The molecular composition of defensive behaviors exerted by each bird. The blood sources for the of this system is largely unknown in mosquitoes with the exception of 168 mosquitoes that successfully obtained a bloodmeal were assessed Anopheles gambiae SRPN2 and CLIPB9, which constitute the first known by amplifying a fragment of the 16s ribosomal gene using generalist regulatory unit that controls melanization. If uncontrolled, e.g. by the avian primers, sequencing each amplified fragment, and comparing the depletion of the inhibitor SRPN2, melanization can kill adult females late fragment to reference sequences. Host selection differed significantly in life, and thus potentially reduce the vectorial capacity of An. gambiae . from random, exhibiting the following preference structure: American This feature makes PPO activation, which is a rate-limiting step in melanin Robins preferred over Blue Jays and over Northern Cardinals, and Northern production, a potential target for novel malaria control strategies. Cardinals preferred over Brown Thrashers. The most common types of Using life table analyses, we determined the consequences of SRPN2 defensive behaviors were those protecting the feet and head, but the depletion by RNAi on several demographic growth parameters under number of defensive behaviors did not differ significantly between hosts. standard laboratory settings. Net reproductive rate (Ro) was decreased by Further experiments are needed to determine the role of these defensive 29%, while mean generation time was unaffected. As a consequence, behaviors in host selection and feeding success by vectors. Our results doubling time (Td) was moderately increased by 9%. The negative indicate a non-random pattern of host selection by vectors that needs to effect on net reproductive rate is largely attributable to a significant be considered when modeling WNV transmission. decrease in bloodfeeding propensity. Bloodfeeding propensity and survival were disproportionally reduced in older mosquitoes after the first 750 two gonotrophic cycles. As a consequence, the number of potentially infectious bites is at least reduced by 83%. Taken together, these INTERACTIVE TOOLS FOR IDENTIFICATION OF MOSQUITO data suggest that SRPN2 constitutes a viable target for novel malaria AND SAND FLY VECTORS OF INFECTIOUS DISEASES intervention strategies. Leopoldo M. Rueda, James E. Pecor, Richard C. Wilkerson, Lewis 752 S. Long, Jason H. Richardson Walter Reed Army Institute of Research, Silver Spring, MD, United States SPATIAL DISTRIBUTION, SEASONALITY AND BEHAVIOR Computerized interactive tools to identify mosquito and sand fly vectors of OF NOVEL MALARIA VECTORS IN THE WESTERN KENYAN infectious human diseases were developed for various regions of the world HIGHLANDS (see Walter Reed Biosystematics Unit/WRBU website, www.wrbu.org). Jennifer C. Stevenson1, Brandy St. Laurent2, Neil Lobo2, Lorna Using LUCID programs, WRBU identification keys for mosquito and sand Culverwell3, Mary Cooke1, Samuel Kahindi4, Chrispin Owaga4, fly vectors and their associated groups included morphological diagnostic Elizabeth Ayoma4, Robin Oriango4, Ralph Harbach3, Chris characters primarily of the head, thorax, abdomen, legs and wings. Drakeley1, Jonathan Cox1 Automontage images of diagnostic characters of various insect body parts 1 were attached to each key. Genus and species pages for selected vectors London School of Hygiene and Tropical Medicine, London, United 2 and related groups were developed, including brief basic taxonomy, Kingdom, Eck Institute for Global Health, University of Notre Dame, 3 distribution, bionomics, medical importance, selected references, and South Bend, IN, United States, Natural History Museum, London, United 4 detailed photos of habitus and other morphological parts. World catalogs Kingdom, Centre for Global Health Research, Kenya Medical Research of mosquitoes and sand flies, with updated taxonomy and hierarchic Institute/Centers for Disease Control and Prevention, Kisumu, Kenya classification were linked to each key. In addition, comprehensive lists of Results from a light trap study carried out in 2010, presented previously, known and potential vectors, and their associated taxonomic information, revealed the presence of previously unidentified mosquito species carrying were included in the WRBU website. New LUCID identification keys were Plasmodium falciparum sporozoites in Kisii district in the western Kenyan recently developed, namely: African Anopheles adult and larval keys highlands, an area prone to epidemics of malaria. The majority of these (include 140+ species and groups for adult key; 120+ for larval key); specimens could not be definitively identified to the species level using the South American Culicine mosquitoes (include vector adult and larval keys commonly used morphological keys, and sequencing revealed that there of Aedes, Culex, Coquillettidia, Haemagogus, Mansonia, Psorophora, were no matching published sequences available at ribosomal ITS2 and www.astmh.org 227 mitochondrial CO1 loci. To further morphologically describe these species, infections, outbreaks of acute fasciolasis can occur in endemic areas study their behavior and investigate their temporal and spatial distribution, related to ingestion of a contaminated food item. Despite the high mosquitoes collected during both longitudinal and transect studies were prevalence of F. hepatica in many areas, its importance has been largely identified morphologically and sequenced at rDNA ITS2 and mtCO1 loci. neglected. We investigated clusters of F. hepatica which occurred in To study spatial and temporal distribution of any novel vectors, monthly four family groups in rural Argentina. A total of 34 confirmed cases pyrethrum spray catches were made to sample indoor resting mosquitoes of acute fascioliasis from 4 different families (15, 6, 8, and 5 affected in 10 villages across Kisii Central, Kisii South and Rachuonyo South districts members) were investigated. Three of the four families were residents over an 18-month period between 2009 and 2011. To determine host- of endemic areas, while a fourth family vacationed in an endemic area. seeking activity and peak biting times, mosquitoes were collected from All members from the 4 families reported ingestion of watercress. The light traps set up indoors and outdoors over a 12-month period from most common clinical symptoms were right upper quadrant pain and June 2011. To fully describe larval and adult stages, a wide range of larval fever, present in all subjects. All cases had elevated liver transaminase breeding sites were sampled across Rachuonyo South in November 2011 tests as well as absolute eosinophilia. Fasciola