| SYNERGISTIC IMPACTS OF MALATHION AND PREDATORY STRESS ON SIX SPECIES OF NORTH AMERICAN TADPOLES | Relyea, Rick A. | 2004 |
KeywordsPredation;Stress;Synergy;Frog;Toad, WNV AbstractThe decline of many amphibian populations is associated with pesticides, but for most pesticides we know little about their toxicity to amphibians. Malathion is a classic example; it is sprayed over aquatic habitats to control mosquitoes that carry malaria and the West Nile virus, yet we know little about its effect on amphibians. I examined the survival of six species of tadpoles (wood frogs, Rana sylvatica; leopard frogs, R. pipiens; green frogs, R. clamitans; bullfrogs, R. catesbeiana; American toads, Bufo americanus; and gray tree frogs, Hyla versicolor) for 16 d in the presence or absence of predatory stress and six concentrations of malathion. Malathion was moderately toxic to all species of tadpoles (median lethal concentration [LC50] values, the concentration estimated to kill 50% of a test population, ranged from 1.25–5.9 mg/L). These values are within the range of values reported for the few amphibians that have been tested (0.2–42 mg/L). In one of the six species, malathion became twice as lethal when combined with predatory stress. Similar synergistic interactions have been found with the insecticide carbaryl, suggesting that the synergy may occur in many carbamate and organophosphate insecticides. While malathion has the potential to kill amphibians and its presence is correlated with habitats containing declining populations, its actual role in amphibian declines is uncertain given the relatively low concentration in aquatic habitats. AuthorsRelyea, Rick A. Year Published2004 PublicationEnvironmental Toxicology and Chemistry LocationsDOI10.1897/03-259 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/15095908 |
| Alligators as West Nile Virus Amplifiers | Klenk, Kaci | 2004 |
KeywordsWNV AbstractRecent evidence suggests that American alligators (Alligator mississippiensis) may be capable of transmitting West Nile virus (WNV) to other alligators. We experimentally exposed 24 juvenile alligators to WNV parenterally or orally. All became infected, and all but three sustained viremia titers >5.0 log10 PFU/mL (a threshold considered infectious for Culex quinquefasciatus mosquitoes) for 1 to 8 days. Noninoculated tankmates also became infected. The viremia profiles and multiple routes of infection suggest alligators may play an important role in WNV transmission in areas with high population densities of juvenile alligators. AuthorsKlenk, Kaci, Snow, Jamie, Morgan, Katrina, Bowen, Richard, Stephens, Michael, Foster, Falicia, Gordy, Paul, Beckett, Susan, Komar, Nicholas, Gubler, Duane and Bunning, Michel Year Published2004 PublicationEmerging Infectious Diseases LocationsDOI10.3201/eid1012.040264 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/15663852 |
| Husbandry of wild-caught greater sage-grouse | Oesterle, P | 2005 |
KeywordsArtemisia, Centrocercus urophasianus, husbandry, sage-grouse, West Nile virus AbstractThis study reports the first successful husbandry and breeding in captivity of wild-caught greater sage-grouse (Centrocercus urophasianus). In October 2003, 21 hatch-year greater sage-grouse were trapped in northwestern Nevada and transported to Fort Collins, Colorado. We held grouse in pens at the United States Department of Agriculture's National Wildlife Research Center for 8 months. We offered a varied diet, including native food items such as sagebrush (Artemisia tridentata and A. tripartita) and yarrow (Achillea millefolium). We housed grouse in a large flight pen and allowed to them free-range as one flock. Mortality rate was 16.7%. Several of the grouse exhibited breeding behavior, and 13 eggs were laid. We describe the techniques used to house and feed wild-caught sage-grouse. This study has conservation implications for captive breeding of this species of concern. AuthorsOesterle, P; McLean, R; Dunbar, M; Clark, L Year Published2005 PublicationWildlife Society Bulletin LocationsDOI10.2193/0091-7648(2005)33[1055:HOWGS]2.0.CO;2 |
| West Nile virus and sage-grouse: What more have we learned? | Naugle, DE | 2005 |
KeywordsCentrocercus urophasianus; emerging infectious disease; monitoring; population decline; sage-grouse; survival; West Nile virus AbstractWest Nile virus (WNv) has emerged as a new issue in the conservation of native avifauna in North America. Mortality associated with WNv infection decreased survival of female greater sage-grouse (Centrocercus urophasianus) by 25% across 4 populations in Wyoming and Montana, USA, and Alberta, Canada, in 2003. In 2004 WNv spread to populations in Colorado and California, and female survival in late summer was 10% lower at 4 sites with confirmed WNv mortalities (86% survival) than at 8 sites without (96%). We still have no evidence that sage-grouse show resistance to the virus. The 2004 WNv season was not the catastrophe that many had predicted, and the decrease in prevalence of infection and mortality in sage-grouse, humans, and horses (except in California) has left many wondering if the worst has past. Evidence suggests that risk of infection was low in 2004 because unseasonably cool summer temperatures delayed or reduced mosquito production. Moreover, mortalities occurred 2-3 weeks later in 2004 than in 2003, and the shift to later timing was consistent between years at sites where WNv reduced survival both years. Mosquito surveillance data indicated a sharp decline in prevalence and infection rate of adult C. tarsalis in southeast Alberta, the most northern latitude where WNv reduced survival, in 2003 but not in 2004. A full understanding of the implications of WNv for sage-grouse requires a long-term, coordinated monitoring strategy among researchers and a sensitivity analysis to evaluate the role of WNv in population viability. Epidemiological research examining the prevalence and ecology of the virus among reservoir hosts is crucial. AuthorsNaugle, DE; Aldridge, CL; Walker, BL; Doherty, KE; Matchett, MR; McIntosh, J; Cornish, TE; Boyce, MS Year Published2005 PublicationWildlife Society Bulletin Locations- Alberta, Canada (49.4, -110.702)
- Phillips County, Montana (48.2, -107.933)
- Central Washington (46.779, -119.486)
- Roundup, Montana (46.4453, -108.541)
- Southern Powder River Basin, Wyoming (44.3442, -106.293)
- Lander, Wyoming (42.8331, -108.73)
- Upper Green River Basin, Wyoming (42.742, -109.869)
- Routt County, Colorado (40.5167, -106.983)
- Moffat County, Colorado. Axial Basin 40 km southwest of Craig, Colorado. (40.2602, -107.881)
- Gunnison County Colorado (38.7, -107.067)
- Mono County, California (37.9167, -118.867)
DOI10.2193/0091-7648(2005)33[616:WNVASW]2.0.CO;2 |
| Drought-Induced Amplification and Epidemic Transmission of West Nile Virus in Southern Florida | Shaman, Jeffrey | 2005 |
KeywordsWest Nile virus, amplification, transmission, Culex nigripalpus, drought, WNV AbstractWe show that the spatial-temporal variability of human West Nile (WN) cases and the transmission of West Nile virus (WNV) to sentinel chickens are associated with the spatial-temporal variability of drought and wetting in southern Florida. Land surface wetness conditions at 52 sites in 31 counties in southern Florida for 2001–2003 were simulated and compared with the occurrence of human WN cases and the transmission of WNV to sentinel chickens within these counties. Both WNV transmission to sentinel chickens and the occurrence of human WN cases were associated with drought 2–6 mo prior and land surface wetting 0.5–1.5 mo prior. These dynamics are similar to the amplification and transmission patterns found in southern Florida for the closely related St. Louis encephalitis virus. Drought brings avian hosts and vector mosquitoes into close contact and facilitates the epizootic cycling and amplification of the arboviruses within these populations. Southern Florida has not recorded a severe, widespread drought since the introduction of WNV into the state in 2001. Our results indicate that widespread drought in the spring followed by wetting during summer greatly increase the probability of a WNV epidemic in southern Florida. AuthorsDay, Jonathan F., Shaman, Jeffrey and Stieglitz, Marc Year Published2005 PublicationJournal of Medical Entomology LocationsDOI10.1603/0022-2585(2005)042[0134:DAAETO]2.0.CO;2 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/15799522 |
| Achieving Operational Hydrologic Monitoring of Mosquitoborne Disease | Shaman, Jeffrey | 2005 |
KeywordsWNV AbstractMosquitoes and mosquitoborne disease transmission are sensitive to hydrologic variability. If local hydrologic conditions can be monitored or modeled at the scales at which these conditions affect the population dynamics of vector mosquitoes and the diseases they transmit, a means for monitoring or modeling mosquito populations and mosquitoborne disease transmission may be realized. We review how hydrologic conditions have been associated with mosquito abundances and mosquitoborne disease transmission and discuss the advantages of different measures of hydrologic variability. We propose that the useful application of any measure of hydrologic conditions requires additional consideration of the scales for both the hydrologic measurement and the vector control interventions that will be used to mitigate an outbreak of vectorborne disease. Our efforts to establish operational monitoring of St. Louis encephalitis virus and West Nile virus transmission in Florida are also reviewed. AuthorsDay, Jonathan F. and Shaman, Jeffrey Year Published2005 PublicationEmerging Infectious Diseases LocationsDOI10.3201/eid1109.050340 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/16229760 |
| Detection of West Nile Viral RNA from an Overwintering Pool of Culex pipens pipiens (Diptera: Culicidae) in New Jersey, 2003 | Farajollahi, Ary | 2005 |
KeywordsWest Nile virus, Culex pipiens pipiens, overwintering, viral RNA detection, WNV AbstractIn total, 1,324 Culex pipiens pipiens L. female mosquitoes were collected at Ft. Hancock, Monmouth County, New Jersey, from January to March 2001–2003. Mosquitoes were held in an insectary at 27°C and a photoperiod of 16:8 (L:D) h for 6 to 21 d after which they were tested in 34 pools. West Nile viral RNA was detected in one pool by a TaqMan reverse transcription-polymerase chain reaction assay; however, infectious virus could not be isolated using either Vero cell plaque assay or C6/36 mosquito cells. Twenty females dissected in January and March 2003 confirmed ovarian diapause status. We suggest that the mode of infection in this pool of overwintering females may have been due to vertical (transgenerational) transmission. AuthorsNasci, Roger S., Godsey, Marvin S., Farajollahi, Ary, Crans, Wayne J., Bryant, Patricia, Wolf, Bruce, Burkhalter, Kristen L. and Aspen, Stephen E. Year Published2005 PublicationJournal of Medical Entomology LocationsDOI10.1603/0022-2585(2005)042[0490:DOWNVR]2.0.CO;2 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/15962803 |
| West Nile Virus in Host-Seeking Mosquitoes within a Residential Neighborhood in Grand Forks, North Dakota | Bell, Jeffrey A. | 2005 |
KeywordsWNV AbstractWest Nile virus (WNV) was first recovered in North Dakota near the city of Grand Forks in June 2002. During 2002, 2003, and 2004, we collected mosquitoes from Grand Forks using Mosquito Magnet™ traps and tested them for WNV. The seasonal abundance, species composition, and reproductive status of female mosquitoes were correlated with local environmental temperature and state surveillance data on WNV to determine the factors affecting local transmission of WNV. Over 90% of the mosquitoes collected were Aedes vexans, Ochlerotatus dorsalis, and Culex tarsalis, but WNV was detected only in Cx. tarsalis. Average summertime temperatures and relative abundance of mosquitoes were highest in 2002 but no WNV-positive mosquitoes were detected until the following summer. In 2003, nulliparous Cx. tarsalis appeared in mid-June (first summer brood), and parous Cx. tarsalis appeared in mid-July. The first WNV-positive pool occurred 21 July, and minimum daily infections rates increased thereafter until 27 August. The minimum infection rate (MIR) for Cx. tarsalis during the season was 5.7 infected mosquitoes per 1,000 tested, with the highest infection rates occurring at the end of the season as Cx. tarsalis populations started to decline. Mid-to-late August was identified as the period of highest risk for being bitten by a WNV-infected mosquito in Grand Forks during 2003. In 2004, viral activity in Grand Forks was low, due to very cool temperatures throughout the summer. To examine the genetic diversity of the 2003 WNV isolates from Grand Forks, we sequenced a 366-nucleotide region of the capsid and premembrane gene. Thirteen (46%) of the 28 WNV isolates contained at least one nucleotide substitution when compared to the homologous region of the progenitor WN NY-99 strain, and seven of these 13 substitutions coded for amino acid changes. Thus, WNV is established in North Dakota, it appears to be evolving and it is vectored primarily by Cx. tarsalis. Vector-Borne Zoonotic Dis. 5, 373–382. AuthorsBell, Jeffrey A., Mickelson, Nathan J. and Vaughan, Jefferson A. Year Published2005 PublicationVector-Borne and Zoonotic Diseases LocationsDOI10.1089/vbz.2005.5.373 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/16417433 |
| Wintering of Neurotropic Velogenic Newcastle Disease Virus and West Nile Virus in Double-Crested Cormorants (Phalacrocorax auritus) from the Florida Keys | Allison, A. B. | 2005 |
KeywordsNewcastle disease virus, double-crested cormorant, fusion protein, West Nile virus, Florida, wintering grounds, reservoir, WNV AbstractDuring November 2002, six double-crested cormorants (DCCs; Phalacrocorax auritus) were found moribund in Big Pine Key, FL, exhibiting clinical signs indicative of neurologic disease. Postmortem diagnostic evaluations were performed on two adult birds. Virulent Newcastle disease virus (NDV) was isolated from a cloacal swab from cormorant 1. West Nile virus (WNV) was isolated from the brain and lung of cormorant 2. Nucleotide sequence analysis of a portion of the fusion (F) protein gene of the NDV cormorant isolate revealed it shared a 100% deduced amino acid identity with only two viruses: the 1992 epizootic cormorant isolate from Minnesota and the 1992 turkey isolate from North Dakota. The epidemiologic significance of the recognition of virulent NDV on cormorant wintering grounds during a nonepizootic period, in addition to the potential implications of the concurrent isolation of NDV and WNV from cormorants, is discussed. AuthorsAllison, A. B., Gottdenker, N. L. and Stallknecht, D. E. Year Published2005 PublicationAvian Diseases LocationsDOI10.1637/7278-091304R Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/16094838 |
| Serologic Survey of Select Infectious Diseases in Coyotes and Raccoons in Nebraska | Bischof, Richard | 2005 |
KeywordsCanine distemper virus, coyote, Francisella tularensis, Leptospira interrogans, Nebraska, raccoon, Rickettsia rickettsi, serology, West Nile virus, WNV AbstractTo obtain data about select zoonotic and other infectious diseases in free-ranging predators in five ecoregions in Nebraska, sera were collected from 67 coyotes (Canis la-trans) and 63 raccoons (Procyon lotor) from November 2002 through January 2003. For coyotes, antibodies were detected against canine distemper virus (CDV, 61%), Francisella tularensis (32%), Rickettsia rickettsi (13%), and flaviviruses (48%). None of the coyote sera had antibodies to Borrelia burgdorferi, Brucella canis, or six serovars of Leptospira interrogans. Because serologic cross-reactivity exists among flaviviruses, 14 sera from flavivirus-positive coyotes were also tested for St. Louis encephalitis virus (SLE) antibodies and two (14%) were positive, suggesting that up to 48% of coyotes tested had antibodies against West Nile virus (WNV). For raccoons, antibodies were detected against CDV (33%), F. tularensis (38%), and three serovars of L. interrogans (11%). AuthorsBischof, Richard and Rogers, Douglas G. Year Published2005 PublicationJournal of Wildlife Diseases LocationsDOI10.7589/0090-3558-41.4.787 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/16456169 |
