| survey of q-fever agglutinins in birds and small rodents in northern california, 1975-76. | serum samples from 15 species of rodents and 33 species of birds were tested for agglutinins against coxiella burnetii by the microagglutination test. of 759 rodents tested, 21 (3%) were seropositive. antibody positive rodents included muskrats, ondatra zebethica, (11%), rattus spp. (10%), beechey ground squirrels, otospermophilus beecheyi, (6%), wood rats, neotoma fuscipes, (5%), and peromyscus spp. (2%). of 583 birds tested, 118 (20%) were seropositive. this included white crowned sparrows, zo ... | 1979 | 522220 |
| the role of indigenous wild, semidomestic, and exotic birds in the epizootiology of velogenic viscerotropic newcastle disease in southern california, 1972-1973. | during an epornitic of velogenic viscerotropic newcastle disease (vvnd) in southern california, free-flying wild birds, captive and free-ranging semidomestic birds, and exotic birds were collected from the quarantine area to determine their role in the epizootiology of the disease. the vvnd virus was isolated from 0.04% of 9,446 free-flying wild birds, 0.76% of 4,367 semidomestic birds, and 1.01% of 3,780 exotic birds examined. three house sparrows and 1 crow directly associated with infected po ... | 1975 | 1176357 |
| the ecology of western equine encephalomyelitis virus in the central valley of california, 1945-1985. | reeves' concept of the summer transmission cycle of western equine encephalomyelitis virus in 1945 was that the virus was amplified in a silent transmission cycle involving mosquitoes, domestic chickens, and possibly wild birds, from which it could be transmitted tangentially to and cause disease in human and equine populations. extensive field and laboratory studies done since 1945 in the central valley of california have more clearly defined the specific invertebrate and vertebrate hosts invol ... | 1987 | 3318522 |
| role of peridomestic birds in the transmission of st. louis encephalitis virus in southern california. | in response to the 1984 st. louis encephalitis (sle) epidemic in the los angeles basin of southern california (usa), an investigative program was initiated to evaluate the interactive components of the sle virus transmission cycle. from 1987 through 1996 (10 yr), 52,589 birds were bled and their sera tested for sle and western equine encephalomyelitis (wee) virus antibodies by the hemagglutination inhibition (hai) test. eighty-three percent of the birds tested were house finches (carpodacus mexi ... | 2000 | 10682741 |
| patterns of avian seroprevalence to western equine encephalomyelitis and saint louis encephalitis viruses in california, usa. | temporal and spatial changes in the enzootic activity of western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses were monitored at representative wetland study sites in the coachella, san joaquin, and sacramento valleys of california from 1996 to 1998 using three methods: (1) virus isolation from pools of 50 host-seeking culex tarsalis coquillett females, (2) seroconversions in flocks of 10 sentinel chickens, and (3) seroprevalence in wild birds collected by mist nets and ... | 2000 | 10916291 |
| role of corvids in epidemiology of west nile virus in southern california. | the invasion of different southern california landscapes by west nile virus (wnv) and its subsequent amplification to epidemic levels during 2004 enabled us to study the impact of differing corvid populations in three biomes: the hot colorado desert with few corvids (coachella valley), the southern san joaquin valley (kern county) with large western scrub-jay but small american crow populations, and the cool maritime coast (los angeles) with a large clustered american crow population. similar su ... | 2006 | 16619622 |
| limited interdecadal variation in mosquito (diptera: culicidae) and avian host competence for western equine encephalomyelitis virus (togaviridae: alphavirus). | historically, western equine encephalomyelitis virus (weev) caused large equine and human epidemics in the americas from canada into argentina. despite recent enhanced surveillance for west nile virus, there have been few reports of equine or human cases and little documented enzootic activity of weev. during the past three years, weev has been active again in california, but without human or equine cases. in the current study, we compared host and vector competence of representative weev isolat ... | 2008 | 18385369 |
| persistent west nile virus transmission and the apparent displacement st. louis encephalitis virus in southeastern california, 2003-2006. | west nile virus (family flaviviridae, genus flavivirus, wnv) invaded the colorado desert biome of southern california during summer 2003 and seemed to displace previously endemic st. louis encephalitis virus (family flaviviridae, genus flavivirus, slev, an antigenically similar flavivirus in the japanese encephalitis virus serocomplex). western equine encephalomyelitis virus (family togaviridae, genus alphavirus, weev), an antigenically distinct alphavirus, was detected during 2005 and 2006, ind ... | 2008 | 18533445 |
| variation in western equine encephalomyelitis viral strain growth in mammalian, avian, and mosquito cells fails to explain temporal changes in enzootic and epidemic activity in california. | the decrease in western equine encephalomyelitis virus (weev; togaviridae, alphavirus) activity in north america over the past 20-30 years has prompted research to determine if there have been concurrent declines in virulence. six (weev) strains isolated from culex tarsalis mosquitoes from california during each of the six preceding decades failed to show a consistent declining temporal trend in virus titer using mosquito (c6/36), avian (duck embryo fibroblast), or mammalian (vero) cells, result ... | 2011 | 21395409 |
| blood-feeding patterns of the culex pipiens complex in sacramento and yolo counties, california. | mosquitoes in the culex pipiens complex are competent vectors of west nile virus (wnv; family flaviviridae, genus flavivirus) in the laboratory, and field-collected mosquitoes have tested positive for the virus in california and elsewhere. a better understanding of cx. pipiens complex blood-feeding patterns will help define the threat that these mosquitoes pose to human health and their role in wnv amplification in northern california. we collected blood-engorged cx. pipiens complex mosquitoes f ... | 2011 | 21485380 |
| Mosquito host selection varies seasonally with host availability and mosquito density. | Host selection by vector mosquitoes is a critical component of virus proliferation, particularly for viruses such as West Nile (WNV) that are transmitted enzootically to a variety of avian hosts, and tangentially to dead-end hosts such as humans. Culex tarsalis is a principal vector of WNV in rural areas of western North America. Based on previous work, Cx. tarsalis utilizes a variety of avian and mammalian hosts and tends to feed more frequently on mammals in the late summer than during the res ... | 2011 | 22206038 |
| vector-host interactions of culex pipiens complex in northeastern and southwestern usa. | studies on the vector-host interactions of culex pipiens complex mosquitoes by sequencing portions of mitochondrial cytochrome b gene indicate that cx. p. pipiens f. pipiens predominantly feed on avian hosts (93.1%), and focus feeding activity on several key bird species, in particular the american robin, the gray catbird, and the house sparrow in connecticut. however, cx. p. quinquefasciatus indiscriminately feed on both birds and mammals. culex p. quinquefasciatus in harris county - texas and ... | 2012 | 23401953 |
| spatial variation in host feeding patterns of culex tarsalis and the culex pipiens complex (diptera: culicidae) in california. | west nile virus (family flaviviridae, genus flavivirus, wnv) is now endemic in california across a variety of ecological regions that support a wide diversity of potential avian and mammalian host species. because different avian hosts have varying competence for wnv, determining the blood-feeding patterns of culex (diptera: culicidae) vectors is a key component in understanding the maintenance and amplification of the virus as well as tangential transmission to humans and horses. we investigate ... | 0 | 22897051 |
| surveys for antibodies against mosquitoborne encephalitis viruses in california birds, 1996-2013. | from 1996 through 2013, 54,546 individual birds comprising 152 species and 7 orders were banded, bled, and released at four study areas within california, from which 28,388 additional serum samples were collected at one or more recapture encounters. of these, 142, 99, and 1929 birds from 41 species were positive for neutralizing antibodies against western equine encephalomyelitis virus (weev), st. louis encephalitis virus (slev), or west nile virus (wnv) at initial capture or recapture, respecti ... | 2016 | 26974395 |
| west nile virus-related trends in avian mortality in california, usa, 2003-12. | west nile virus (wnv) is an arbovirus transmitted enzootically by culex mosquitoes among avian hosts. since 2000, the california dead bird surveillance program (dbsp) has tracked avian mortality reported by the public on a telephone hotline and website and measured the prevalence of wnv infection in dead birds. we summarize herein wnv prevalence in dead birds tested and variation of wnv transmission over time and space with the use of dbsp data from 2003 to 2012. prevalence among dead birds was ... | 2015 | 25919466 |
| host (avian) biting preference of southern california culex mosquitoes (diptera: culicidae). | the host preference of a vector mosquito species plays a significant role in determining human and animal risk of infection with mosquito-transmitted pathogens. host preferences of common southern california culex species for four bird species, american crow (corvus brachyrhynchos), house sparrow (passer domesticus), house finch (carpodacus mexicanus), and mourning dove (zenaida macroura), were examined by determining the proportion of each mosquito species that successfully engorged on each of ... | 2012 | 22679878 |