West Nile Virus Infection in Birds and Mosquitoes, New York State, 2000.West Nile West Nile may refer to:
New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of State in 2000, with the epicenter ep·i·cen·ter n. 1. The point of the earth's surface directly above the focus of an earthquake. 2. A focal point: stood at the epicenter of the international crisis. in New York City New York City: see New York, city. New York City City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. and surrounding counties. We tested 3,403 dead birds and 9,954 mosquito mosquito (məskē`tō), small, long-legged insect of the order Diptera, the true flies. The females of most species have piercing and sucking mouth parts and apparently they must feed at least once upon mammalian blood before their eggs can pools for WN virus during the transmission season. Sixty-three avian avian /avi·an/ (a´ve-an) of or pertaining to birds. a·vi·an adj. Of, relating to, or characteristic of birds. species, representing 30 families and 14 orders, tested positive for WN virus. The highest proportion of dead birds that tested positive for WN virus was in American Crows in the epicenter (67% positive, n=907). Eight mosquito species, representing four genera genera, in taxonomy: see classification. , were positive for WN virus. The minimum infection rate per 1,000 mosquitoes (MIR) was highest for Culex Culex /Cu·lex/ (ku´leks) a genus of mosquitoes found throughout the world, many species of which are vectors of disease-producing organisms. Cu·lex n. pipiens in the epicenter: 3.53 for the entire season and 7.49 for the peak week of August 13. Staten Island Staten Island (1990 pop. 378,977), 59 sq mi (160 sq km), SE N.Y., in New York Bay, SW of Manhattan, forming Richmond co. of New York state and the borough of Staten Island of New York City. had the highest MIR (11.42 for Cx. pipiens), which was associated with the highest proportion of dead American Crows that tested positive for WN virus (92%, n=48) and the highest number of human cases (n=10). The emergence of West Nile (WN) virus in 1999 in four U.S. states A U.S. state is any one of the fifty subnational entities of the United States, although four states use the official title "commonwealth". The separate state governments and the federal government share sovereignty, in that an American is a citizen both of the federal entity and (1) was followed by its spread to 12 states in 2000 (2). An enzootic en·zo·ot·ic adj. Prevalent among or restricted to animals of a specific geographic area. Used of a disease. n. An enzootic disease. enzootic peculiar to or present constantly in a location. See also endemic. cycle was established between birds and mosquitoes, and WN disease was observed in humans, horses, and birds in both years (2,3). Bird deaths due to WN virus are unusual outside North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. , with the exception of deaths of geese geese domestic geese which were derived from the wild goose Anser anser. There are many other species in this genus and in the other genus of geese, the Branta spp. of which Branta canadensis is typical. in Israel (4) and pigeons in Egypt (5). In 1999 in North America, WN disease, characterized by meningoencephalitis meningoencephalitis /me·nin·go·en·ceph·a·li·tis/ (me-ning?go-en-sef?ah-li´tis) inflammation of the brain and meninges. toxoplasmic meningoencephalitis and myocarditis Myocarditis Definition Myocarditis is an inflammatory disease of the heart muscle (myocardium) that can result from a variety of causes. While most cases are produced by a viral infection, an inflammation of the heart muscle may also be instigated by , was observed in 14 species of wild and captive birds (6). WN virus has been detected in a number of mosquito genera in North America, including Culex and Aedes species (2,7). Vector competence has been confirmed experimentally for some North American North American named after North America. North American blastomycosis see North American blastomycosis. North American cattle tick see boophilusannulatus. species, including Cx. pipiens, Ae. vexans, and Ae. japonicus (8,9). We have summarized surveillance data for WN virus in dead birds and mosquitoes for New York State in the 2000 transmission season. A quantitative and kinetic kinetic /ki·net·ic/ (ki-net´ik) pertaining to or producing motion. ki·net·ic adj. Of, relating to, or produced by motion. kinetic pertaining to or producing motion. analysis of data within and outside the epicenter is shown for both the bird and mosquito samples. Vertebrate vertebrate, any animal having a backbone or spinal column. Verbrates can be traced back to the Silurian period. In the adults of nearly all forms the backbone consists of a series of vertebrae. All vertebrates belong to the subphylum Vertebrata of the phylum Chordata. and invertebrate invertebrate (ĭn'vûr`təbrət, –brāt'), any animal lacking a backbone. The invertebrates include the tunicates and lancelets of phylum Chordata, as well as all animal phyla other than Chordata. WN virus infections are compared for counties in the epicenter. Materials and Methods Bird and Mosquito Samples Dead birds were collected and mosquitoes were trapped by local county health units and other agencies as part of the New York State WN virus surveillance effort. Dead birds were necropsied at the Wildlife Pathology Unit at the Department of Environmental Conservation. Kidney, brain, heart, liver, or spleen spleen, soft, purplish-red organ that lies under the diaphragm on the left side of the abdominal cavity. The spleen acts as a filter against foreign organisms that infect the bloodstream, and also filters out old red blood cells from the bloodstream and decomposes were harvested and stored at -70 [degrees] C. Additional avian tissue samples sent to the National Wildlife Health Center were not included in this analysis because selection criteria and testing procedures differed. Mosquitoes were trapped, speciated, grouped into pools of 5 to 50, and stored at -70 [degrees] C. For some pools, Cx. pipiens and Cx. restuans were not separated but were pooled together and denoted as Cx. pipiens-restuans. The Aedes genus genus, in taxonomy: see classification. genus Biological classification. It ranks below family and above species, consisting of structurally or phylogenetically (see is being reclassified into two genera, Aedes and Ochlerotatus (10), but is classified as Aedes in this manuscript. Avian tissue samples and mosquito pools were sent to the Arbovirus arbovirus Any of a large group of viruses that develop in arthropods (chiefly mosquitoes and ticks). The name derives from “arthropod-borne virus.” The spheroidal virus particle is encased in a fatty membrane and contains RNA; it causes no apparent harm to the Laboratory at the Wadsworth Center for WN virus testing. The transmission season was defined as May 15 to October 31, 2000, with the first and last positive samples collected on May 22 and October 31, 2000, respectively. Two positive birds were found earlier in the year (a hawk on February 6 and a crow on April 1), but they were not followed by other positive specimens and did not therefore appear to represent the beginning of the mosquito-borne WN virus transmission season. WN Virus Testing Samples were processed and WN virus assays were performed as described by Shi et al. (11). Briefly, RNA RNA: see nucleic acid. RNA in full ribonucleic acid One of the two main types of nucleic acid (the other being DNA), which functions in cellular protein synthesis in all living cells and replaces DNA as the carrier of genetic was extracted from bird tissue or pools of [is less than or equal to] 50 mosquitoes, and real-time reverse transcription-polymerase chain reaction (RT-PCR RT-PCR reverse transcriptase-polymerase chain reaction. See PCR1. ) was performed (TaqMan, ABI Abi (ā`bī) [short for Abijah], in the Bible, King Hezekiah's mother. (Application Binary Interface) A specification for a specific hardware platform combined with the operating system. Prism 7700 Sequence Detector, Applied Biosystems Applied Biosystems, Inc. (formerly NASDAQ: ABIO) is the original name of a pioneer biotechnology company founded in 1981 in Foster City, California, among the Silicon Valley cities of the southern San Francisco Bay Area. , Foster City, CA). Confirmatory tests included a second TaqMan primer-probe set, standard RT-PCR, virus isolation in cell culture, and immunofluorescence Immunofluorescence A technique that uses a fluorochrome to indicate the occurrence of a specific antigen-antibody reaction. The fluorochrome labels either an antigen or an antibody. assays (for avian tissues). A sample was confirmed as positive if at least two different test results were positive. Other Arbovirus Testing Virus isolation was attempted for all Aedes species (with the exception of some Ae. vexans pools), all Culiseta species, and most WN virus-positive mosquito pools (with the exception of some Cx. pipiens and Cx. pipiens-restuans pools). Samples were inoculated onto monolayers of Vero or C6/36 cells. Viruses from positive cultures were typed by using serogroup-specific polyclonal polyclonal /poly·clo·nal/ (-klon´'l) 1. derived from different cells. 2. pertaining to several clones. polyclonal derived from different cells; pertaining to several clones. antisera for bunyaviruses (California and Bunyamwera serogroups), flaviviruses, alphaviruses, and rhabdoviruses (Hart Park serogroup). California serogroup isolates were further characterized by sequence analysis. Definition of the Epicenter and Radial radial /ra·di·al/ (ra´de-al) 1. pertaining to the radius of the arm or to the radial (lateral) aspect of the arm as opposed to the ulnar (medial) aspect; pertaining to a radius. 2. Regions The epicenter of the New York State epizootic ep·i·zo·ot·ic adj. Affecting a large number of animals at the same time within a particular region or geographic area. Used of a disease. ep was defined as follows. The minimum infection rate (MIR) of each mosquito species was calculated for each county or New York City borough by the standard formula: (number of WN virus-positive mosquito pools/total number of mosquitoes tested) x 1000. The MIR was calculated only when at least 1,000 mosquitoes were tested per species per county or borough. When the MIR was at least 1.0 for any mosquito species in a region, the county or borough was included in the epicenter. In addition, any counties that bordered at least two other epicenter counties or boroughs were included in the definition. The epicenter included the five boroughs of New York City (the Bronx, Brooklyn, Manhattan, Queens, and Staten Island) and the four counties immediately east and north of New York City (Nassau, Suffolk, Rockland, and Westchester counties). For both 1999 and 2000, all human cases of WN virus in New York State were in one of these counties (2,7). Counties outside the epicenter (the "non-epicenter") were divided into four radial regions, R1 to R4, with increasing distance from the epicenter (Figure 1). Radial regions were defined as follows: R1 = Putnam, Orange, Dutchess, Sullivan, and Ulster Ulster, northernmost of the historic provinces of Ireland. Modern Ulster consists of nine counties. Six (Antrim, Armagh, Down, Fermanagh, Derry, and Tyrone) now make up Northern Ireland (see Ireland, Northern), which is often referred to as Ulster; the remaining counties; R2 = Columbia, Delaware, Greene, Rensselaer, Montgomery, Albany, Otsego, Broome, Cortland, Schenectady, Schoharie, and Chenango counties; R3 = Fulton, Essex, Hamilton, Herkimer, Allegany, Lewis, Chemung, Madison, Cayuga, Schuyler, Yates, Washington, Warren, Tompkins, Tioga, Steuben, Onondaga, Seneca, Saratoga, Ontario, Oswego, and Oneida counties Oneida County is the name of several counties in the United States:
1. a meeting, usually held in the summer outdoors or under a temporary tent, providing public lectures combined with entertainment such as concerts and plays. It originated in the village of Chautauqua, N. Y. , Erie, Clinton, Genesee, Jefferson, Orleans, St. Lawrence, Niagara, Franklin, and Livingston counties Livingston County is the name of several counties in the United States:
[ILLUSTRATION OMITTED] Results During the 2000 transmission season, WN virus testing was performed on 3,403 dead birds, representing 153 species, 46 families, and 18 orders. The 1,201 WN virus-positive birds represented 63 species, 30 families, and 14 orders (Table 1). The percentage of WN virus-positive birds was 35% for all birds submitted for testing from throughout the state. Avian species that were [is greater than] 35% positive and for which at least 10 birds were tested included American Kestrel kestrel Any of several birds of prey (genus Falco) known for hovering while hunting. Kestrels prey on large insects, birds, and small mammals. The male is more colourful than the female. Kestrels are mainly Old World birds, but one species, the American kestrel (F. (57%, n=14), Cedar Waxwing cedar waxwing: see waxwing. (60%, n=10), Ovenbird ovenbird, common name for a member of the family Furnariidae, primitive passerine birds, which build elaborate, domed nests of clay or dig tunnels in the ground to lay their eggs. (50%, n=18), American Crow (47%, n=1,687), Fish Crow fish crow n. A crow (Corvus ossifragus) native to the coastal regions and rivers of the eastern United States. (47%, n=45), and Red-tailed Hawk (43%, n=14). The discrepancies in number of birds tested make comparisons between species difficult.
Table 1. Birds positive for West Nile virus in New York State
during the 2000 season(a)
Order Family Common name
Anseriformes Anatidae Domestic Goose
Canada Goose
Mute Swan
Apodiformes Trochilidae Ruby-throated Hummingbird
Caprimulgiformes Caprimulgidae Common Nighthawk
Charadriiformes Charadriidae Killdeer
Laridae Herring Gull
Ring-billed Gull
Greater Black-backed Gull
Rynchopidae Black Skimmer
Scolopacidae Ruddy Turnstone
Ciconiiformes Ardeidae Least Bittern
Green Heron
Great Blue Heron
Columbiformes Columbidae Mourning Dove
Rock Dove
Coraciiformes Alcedinidae Belted Kingfisher
Falconiformes Accipitridae Red-tailed Hawk
Sharp-shinned Hawk
Cooper's Hawk
Broad-winged Hawk
Falconidae Merlin
American Kestrel
Galliformes Meleagrididae Domestic Turkey
Eastern Wild Turkey
Phasianidae Peacock
Ring-necked Pheasant
Tetraonidae Chicken
Ruffed Grouse
Gruiformes Rallidae Virginia Rail
Passeriformes Bombycillidae Cedar Waxwing
Corvidae Fish Crow
American Crow
Blue Jay
Fringillidae Zebra Finch
Song Sparrow
American Goldfinch
House Finch
Cardinal
Icteridae Red-winged Blackbird
Common Grackle
Mimidae Gray Catbird
Northern Mockingbird
Parulidae Black-throated Blue Warbler
Canada Warbler
Warbler
Yellow-rumped Warbler
Ovenbird
Ploceidae House Sparrow
Sturnidae European Starling
Turdidae Veery
Eastern Bluebird
American Robin
Wood Thrush
Tyrannidae Eastern Phoebe
Pelecaniformes Phalacrocoracidae Cormorant
Double Crested Cormorant
Psittaciformes Cacatuidae Cockatoo
Cockatiel
Psittacidae Macaw
Parakeet
Strigiformes Strigidae Snowy Owl
Great Horned Owl
Order No. tested % positive
Anseriformes 2 50
15 33
3 33
Apodiformes 5 20
Caprimulgiformes 2 50
Charadriiformes 3 33
9 33
66 32
7 29
1 100
1 100
Ciconiiformes 1 100
3 33
29 10
Columbiformes 83 19
41 17
Coraciiformes 6 33
Falconiformes 14 43
17 35
30 30
7 14
5 100
14 57
Galliformes 1 100
3 67
8 25
16 25
14 29
131 21
Gruiformes 2 50
Passeriformes 10 60
45 47
1,687 47
500 29
1 100
5 60
4 50
8 38
3 33
6 17
53 13
22 23
10 20
1 100
1 100
1 100
1 100
18 50
127 13
23 17
3 33
4 25
74 22
5 20
2 50
Pelecaniformes 2 100
2 50
Psittaciformes 1 100
5 60
1 100
9 22
Strigiformes 2 100
16 19
(a) Season defined as May 15, 2000, through October 31, 2000.
The percentage of WN virus-positive birds was analyzed an·a·lyze tr.v. an·a·lyzed, an·a·lyz·ing, an·a·lyz·es 1. To examine methodically by separating into parts and studying their interrelations. 2. Chemistry To make a chemical analysis of. 3. for the epicenter and non-epicenter regions. Data are included for avian species for which at least 10 birds were tested in one of the regions (Table 2). For all submitted birds, 51% and 23% WN virus-positive birds were found in the epicenter and non-epicenter regions, respectively. WN virus infection in dead birds was highest for American Crows (67%) in the epicenter. In the non-epicenter, WN virus infection for crows was lower, similar to infection in all birds in this region. High numbers of crows were tested in both regions, and the percentage positive differed by almost threefold.
Table 2. Summary of birds tested for West Nile virus in New York
during the 2000 season(a)
Epicenter Non-epicenter
% WN % WN
No. virus No. virus
Common name tested positive tested positive
American Crow 907 67 780 23
Fish Crow 31 55 14 29
Blue Jay 191 40 309 23
Cooper's Hawk 11 27 19 32
Sharp-shinned Hawk <10 NA(b) 14 36
American Robin 11 9 59 22
House Sparrow 107 8 20 40
European Starling 15 7 <10 NA
Common Grackle 27 7 26 19
Gray Catbird <10 NA 16 25
Ovenbird <10 NA 12 75
Common Yellow Throat 19 0 <10 NA
Mallard <10 NA 12 0
Ring-billed Gull <10 NA 66 32
Great Blue Heron <10 NA 28 7
Rock Dove 16 0 25 28
Mourning Dove <10 NA 77 19
Ring-necked Pheasant <10 NA 15 27
Chicken <10 NA 10 30
Ruffed Grouse <10 NA 130 21
Great Horned Owl <10 NA 15 20
Total(c) 1,502 51 1,901 23
(a) Season defined as May 15, 2000, through October 31, 2000. Bird
species were included only if at least 10 birds were tested for one
of the regions throughout the season.
(b) NA = not applicable because of the low number of birds tested.
(c) All birds tested in each region throughout the season.
WN virus infection in dead birds was examined over time for American Crows and all other birds in the epicenter and four radial regions in New York State (Figure 2). Comparison of American Crows in the five regions (Figure 2A) revealed the highest peak in the epicenter during September. In addition, the peak for American Crows in the epicenter was much broader than for the other four regions. For September, the peaks for American Crows in R1 and R2 were greater than those in the more distant regions, R3 and R4, suggesting a minor extension of the epicenter during this month. Comparison of all birds except American Crows in the five regions (Figure 2B) revealed little difference between the regions, even for the epicenter. These data support the hypothesis that the susceptibility susceptibility the state of being susceptible. Refers usually to infectious disease but may be to physical factors such as wetting or to psychological factors such as harassment. to WN disease was greatest in crows in the epicenter. [GRAPHS OMITTED] We tested 9,954 mosquito pools with 317,668 mosquitoes, representing 28 species and eight genera (Table 3). Of eight positive species representing four genera, most positive pools were Culex species This is a list of described Culex species around the world, as of 2006. Subspecies have been omitted. There are possibly errors and inaccuracies in this list that stem from the conversion from the source. Please check the original source when in doubt. (n=341), compared with only 22 positive pools in the other three genera. All but five of the positive pools were collected in the epicenter. The MIR was calculated for each species in the epicenter for which at least 1,000 mosquitoes were tested (Table 3). In the epicenter, the MIR ranged from 0.47 to 3.55. The MIR of Cx. pipiens was the highest for an individual species. All the pure Cx. restuans pools were negative, and the MIR for Cx. pipiens-restuans was almost half that of the pure Cx. pipiens pools; therefore, the positive mosquitoes in the mixed pools of Cx. pipiens-restuans were most likely Cx. pipiens. The MIRs for Cx. pipiens and Cx. pipiens-restuans were compared with the percentage of positive American Crows in the epicenter for each week of the transmission season (Figure 3). The MIRs for Cx. pipiens and Cx. pipiens-restuans peaked 3 and 2 weeks, respectively, before the peak for positive crows. These data support the hypothesis that Cx. pipiens is an important enzootic vector of WN virus in New York. [GRAPH OMITTED]
Table 3. Summary of mosquitoes tested for West Nile virus in New
York State in 2000
Epicenter
Total
Total Total positive
Mosquito species mosquitoes pools pools MIR(a)
Aedes abserratus-punctor NC(b) NC NC NC
Ae. canadensis 8,018 167 0 0
Ae. cantator 1,615 65 1 0.62
Ae. cinereus 340 15 0 NA(c)
Ae. communis NC NC NC NC
Ae. communis group NC NC NC NC
Ae. intrudens 21 1 0 NA
Ae. japonicus 3,342 257 2 0.60
Ae. sollicitans 5,003 131 0 NA
Ae. stimulans NC NC NC NC
Ae. stimulans group 153 3 0 NA
Ae. taeniorhynchus 395 11 0 NA
Ae. trichuris NC NC NC NC
Ae. triseriatus 2,956 203 3 1.01
Ae. trivittatus 4,289 184 0 0
Ae. vexans 21,486 761 10 0.47
Aedes species 1,340 72 1 0.75
Anopheles crucians 13 2 0 NA
An. punctipennis 165 37 1 NA
An. quadrimaculatus 66 18 0 NA
An. walkeri NC NC NC NC
Anopheles species 16 2 0 NA
Coquillettidia perturbans 8,167 157 0 0
Culiseta melanura 8,189 211 0 0
Cs. morsitans NC NC NC NC
Culiseta species 98 3 0 NA
Culex pipiens 22,120 831 78 3.53
Cx. pipiens-restuans(d) 114,517 3,208 211 1.84
Cx. restuans 3,403 190 0 0
Cx. salinarius 19,541 483 31 1.59
Cx. territans 76 15 0 NA
Culex species 5,358 200 19 3.55
Orthopodomyia alba NC NC NC NC
Psorophora ferox 63 10 1 NA
Uranotaenia sapphirina 208 19 0 NA
Unidentified 1,173 26 0 0
TOTAL 232,131 7,282 358
Non-epicenter
Total
Total Total positive
Mosquito species mosquitoes pools pools
Aedes abserratus-punctor 214 9 0
Ae. canadensis 8,269 145 0
Ae. cantator 993 22 0
Ae. cinereus 247 10 0
Ae. communis 335 12 0
Ae. communis group 235 8 0
Ae. intrudens NC NC NC
Ae. japonicus 3,871 271 3
Ae. sollicitans 1 1 0
Ae. stimulans 42 1 0
Ae. stimulans group 540 17 0
Ae. taeniorhynchus 11 1 0
Ae. trichuris 23 2 0
Ae. triseriatus 6,335 206 0
Ae. trivittatus 2,453 79 0
Ae. vexans 13,490 422 0
Aedes species NC NC NC
Anopheles crucians NC NC NC
An. punctipennis 291 17 0
An. quadrimaculatus 59 3 0
An. walkeri 833 22 0
Anopheles species NC NC NC
Coquillettidia perturbans 10,874 206 0
Culiseta melanura 6,281 178 0
Cs. morsitans 1,821 85 0
Culiseta species NC NC NC
Culex pipiens 8,698 288 1
Cx. pipiens-restuans(d) 16,228 537 1
Cx. restuans 794 48 0
Cx. salinarius 704 17 0
Cx. territans NC NC NC
Culex species 1,108 32 0
Orthopodomyia alba 101 3 0
Psorophora ferox 162 6 0
Uranotaenia sapphirina 419 18 0
Unidentified 105 6 0
TOTAL 85,537 2,672 5
(a) MIR = minimal infection rate per 1,000 mosquitoes. MIR calculated
as (number of WN virus-positive pools by RT-PCR/total mosquitoes
tested) x 1,000. MIR was calculated only if a minimum of 1,000
mosquitoes was tested from a defined region throughout the season.
None of the counties outside the epicenter met this criterion.
(b) NC = not collected.
(c) NA = not applicable because <1,000 mosquitoes were collected.
(d) Cx. pipiens and Cx. restuans were not separated and were
pooled together.
The epicenter was examined as individual boroughs and counties to compare vertebrate and invertebrate WN virus infections (Table 4). The percentage of positive American Crows was calculated, and human and equine equine Any member of the ungulate family Equidae, which includes the modern horses, zebras, and asses, all in the genus Equus, as well as more than 60 species known only from fossils. Equines descended from the dawn horse (see Eohippus). cases were noted for each county over the entire season. The MIRs of mosquitoes from each county were calculated for species with at least 1000 mosquitoes tested. Six mosquito species or groups met this criterion. The highest number of vertebrates infected in·fect tr.v. in·fect·ed, in·fect·ing, in·fects 1. To contaminate with a pathogenic microorganism or agent. 2. To communicate a pathogen or disease to. 3. To invade and produce infection in. with WN virus was found in Staten Island and was associated with the highest mosquito MIRs. This borough had measurable MIRs for five mosquito groups: Cx. pipiens, Cx. species, Cx. pipiens-restuans, Cx. salinarius, and Ae. vexans.
Table 4. Comparison of infection in vertebrates and minimal infection
rate in mosquitoes for WN virus in the epicenter of the New York
epizootic of 2000
MIR(a)
% positive No. No. Cx.
Borough crows human equine Culex pipiens-
or county (n)(b) cases(c) cases(a) pipiens restuans(e)
Staten
Island 92% (48) 10 1 11.42 9.9
Brooklyn 73% (48) 2 0 3.12 1.42
Manhattan 85% (34) 1 0 2.91 3.86
Queens 64% (25) 1 0 0.16 0.24
Suffolk 70% (188) 0 8 NC 2.74
Bronx 44% (9) 0 2 2.38 NA
Rockland 76% (280) 0 0 NA 1.98
Westchester 44% (128) 0 0 0.51 0.73
Nassau 56% (147) 0 4 NC 0.28
MIR(a)
Borough Culex Cx. sali- Aedes Ae.
or county species narius vexans japonicus
Staten
Island 6.92 2.61 0.79 NC(f)
Brooklyn NA(g) 0.67 NA NC
Manhattan NA NA NA NC
Queens 0 0.2 NA NA
Suffolk NC NC 0.40 NA
Bronx NA 0.87 0 NC
Rockland NA NA 0.44 NA
Westchester NC NC 0 0.43
Nassau NC NC 0.45 NC
(a) MIR = minimal infection rate per 1,000 mosquitoes. Mosquito
species were included only if a minimum of 1,000 total mosquitoes
was collected throughout the season for the county. MIR was
calculated as (number of WN virus-positive pools by RT-PCR/total
mosquitoes tested) x 1,000.
(b) Percentage WN virus-positive crows throughout the transmission
season with total number of crows tested in parentheses.
(c) Human cases reported by the Centers for Disease Control
and Prevention (2).
(d) Equine cases reported by S. Trock (personal communication).
(e) Cx. pipiens and Cx. restuans were not separated and were
pooled together.
(f) NC = not collected.
(g) NA = not applicable because <1,000 mosquitoes were collected.
Virus isolation was performed on mosquito samples by cell culture. WN virus was isolated from 110 samples, including Cx. pipiens-restuans (n=60), Cx. pipiens (n=25), Cx. salinarius (n=13), Culex species (n=9), Ae. triseriatus (n=1), Ae. vexans (n=1), and Psorophora ferox (n=1). No virus was isolated from any of the WN virus RNA-positive pools of Ae. japonicus, Ae. cantator, and An. punctipennis. Pools that were negative on Vero cell Vero cells are lineages of cells used in cell cultures.[1] The Vero lineage was isolated from kidney epithelial cells extracted from African green monkey (Cercopithecus aethiops). culture were passaged repeatedly in Aedes albopictus Noun 1. Aedes albopictus - striped native of Japan thriving in southwestern and midwestern United States and spreading to the Caribbean; potential carrier of serious diseases Asian tiger mosquito (C6/36) cells; these further attempts to isolate virus were unsuccessful. Other viruses isolated were trivittatus virus from Ae. trivittatus (n=4) and Ae. triseriatus (n=1), Cache Valley virus Cache Valley virus one of the California serotype bunyaviruses associated with equine viral encephalomyelitis. Cache Valley virus Virology A common Bunyamwera virus, isolated in Utah in 1956 and recovered primarily from mosquitos–genera from Ae. trivittatus (n=2) and Ae. triseriatus (n=2), and Flanders virus from Cx. pipiens-restuans (n=7), Cx. pipiens (n=2), and Cs. melanura (n=11). Eastern equine encephalitis virus Eastern equine encephalomyelitis virus (EEE), commonly called sleeping sickness or "Triple E", is a zoonotic alphavirus and arbovirus present in North, Central and South America and the Caribbean. and California group viruses other than trivittatus were not isolated from any of the Culiseta or Aedes pools. Conclusion In the 2000 transmission season in New York State, we found 63 bird species infected with WN virus, compared with 14 species in 1999 (6). The percentage of WN virus-positive birds was higher in the epicenter than outside it. This high percentage almost entirely reflects infected crows in the epicenter; no increase in WN virus infection was noted in birds other than crows. In contrast, high WN virus infection of dead crows was not observed outside the epicenter, where the percentage of WN virus positivity was similar in crows and other birds over the entire season. High numbers of dead crows were also observed in 1999 (3,6). The cause of the increased sensitivity of crows to WN disease or infection is unknown, but may be due to virus-host interactions, mosquito-bird interactions, mosquito feeding preferences, crow population density, or crow behavior. The presence of WN virus in dead birds does not indicate a definitive diagnosis of WN virus as the cause of death. Many of the birds did not show gross pathologic pathologic /patho·log·ic/ (path?ah-loj´ik) 1. indicative of or caused by some morbid condition. 2. pertaining to pathology. lesions of WN disease (12). In addition, the rate of WN virus-positive birds in our surveillance samples is not equivalent to prevalence of infection, since we are sampling only dead birds. The analysis of percentage positive birds over time revealed differences between various regions in New York State. The percentage of WN virus-positive crows was highest in the epicenter compared with other regions of New York State throughout the season, supporting the importance of crows as indicators in the epizootic. The percentage of WN virus-positive crows was higher than that for all other birds early in the season only in the epicenter. Outside the epicenter, the percentages of WN virus-positive crows and all other birds were similar until the peak month of September. At this time, the two radial regions closest to the epicenter showed higher infection in crows than in other birds, suggesting that the intense level of viral activity may have spread beyond the epicenter. An explanation for this apparent spread may be increased movement of crows during the fall. The surveillance data on avian deaths have implications for future surveillance activities. The similar percentages of positive crows and other birds outside the epicenter indicate the importance of testing all birds, not only crows, outside the epicenter. Sampling errors are likely with the avian surveillance samples. The samples were from dead birds submitted to the Wildlife Pathology Unit, which relied on the cooperation of the general public, individual county health departments, and other agencies; therefore, surveillance samples do not represent a random sampling of dead birds throughout the state. The size and degree of urbanization of various bird species may have resulted in differences in submission. For example, large urban-dwelling species, such as crows, were more likely to have been submitted than small rural dwellers. In addition, more birds were likely sampled from areas with human cases, greater media coverage, and higher human population. The similarity in WN virus infection in birds other than crows from different regions suggests that the impact of sampling bias was not significant. Additionally, specimens submitted for testing to the Wadsworth Center from the Wildlife Pathology Unit represent a sample of those submitted by the public. Sampling at this level may introduce further bias into our surveillance sample. The similarity in WN virus infection in birds other than crows outside the epicenter, however, suggests that such bias was minimal. The highest MIR for mosquitoes in the epicenter was for Cx. pipiens. Positive pools of Cx. pipiens also were identified in 1999 in New York (13). Cx. pipiens-pipiens mosquitoes feed almost exclusively on birds (14); thus, they are likely an important enzootic vector in the bird-mosquito cycle in North America. Other Cx. species have been implicated im·pli·cate tr.v. im·pli·cat·ed, im·pli·cat·ing, im·pli·cates 1. To involve or connect intimately or incriminatingly: evidence that implicates others in the plot. 2. as enzootic vectors worldwide (15). High MIRs of Cx. pipiens and Cx. salinarius were associated with human and equine WN virus cases and high infection rates of crows in counties in the epicenter. Cx. salinarius feeds on both birds and mammals The class Mammalia (the Mammals) is divided into two subclasses based on reproductive techniques: egg laying mammals (the Monotremes); and mammals which give live birth. The latter subclass is divided into two infraclasses: pouched mammals (the marsupials); and the placental mammals. (16); therefore, it is a likely candidate as a "bridge vector," transmitting the virus from bird to mammal mammal, an animal of the highest class of vertebrates, the Mammalia. The female has mammary glands, which secrete milk for the nourishment of the young after birth. . Cx. salinarius has been proposed as a bridge vector for Eastern equine encephalitis virus (17). All MIR data were calculated by using RT-PCR-positive pools and therefore cannot be directly compared with MIRs calculated by using infectious virus-positive pools. No virus was isolated from five RNA-positive pools of Ae. japonicus, even after six serial passages through C6/36 cells. Much attention has been focused on this species because it has been reported to be a highly competent laboratory vector of WN virus (9), but current field data do not support this experimental observation. Different populations of Ae. japonicus have been described in the eastern United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. (18), and differences in vector competence between the populations may explain the discrepancy DISCREPANCY. A difference between one thing and another, between one writing and another; a variance. (q.v.) 2. Discrepancies are material and immaterial. between the field and experimental data. The possibility of sampling error also exists for the mosquito surveillance samples. Individual counties collected mosquitoes in different numbers and set traps by different criteria. In addition, some counties used mosquito adulticides or larvicides during the season. These sources of bias are unlikely to have been uniformly introduced, and their impact on our analyses is unclear. The results from the 2000 surveillance season for WN virus leave a number of unanswered questions. Many avian species can become infected with WN virus, but the prevalence of infection for each species is unknown without systematic serosurveys of the wild bird population. It is also unknown which birds have a high enough viremia viremia /vi·re·mia/ (vi-re´me-ah) the presence of viruses in the blood. vi·re·mi·a n. The presence of viruses in the bloodstream. for efficient transmission to the vector. The apparent mortality rate caused by WN virus is higher for crows than for other birds, but laboratory experiments are required to determine WN virus mortality rates and the pathogenic path·o·gen·ic or path·o·ge·net·ic adj. 1. Having the capability to cause disease. 2. Producing disease. 3. Relating to pathogenesis. mechanisms in crows and other avian species. In addition to crows, many other birds, such as raptors and other corvids, also showed significant pathology. Some nonmigrating species (e.g., ruffed grouse ruffed grouse: see grouse. ruffed grouse North American species (Bonasa umbellus) of grouse, sometimes incorrectly called a partridge. Ruffed grouse live mainly on berries, fruits, seeds, and buds but also eat much animal food. ) have potential use as an indicator species for WN virus infection. Vector competence, blood meal identification, and transovarial transmission Transovarial transmission occurs in certain arthropod vectors as they transmit disease-causing bacteria from parent arthropod to offspring arthropod. For instance, Rickettsia rickettsii studies for the potential mosquito vectors are also important research areas. Acknowledgments We thank the WN virus surveillance team, especially the New York City Department of Health and the local county health units, who collected the surveillance specimens. We also thank H. Taber for helpful discussions. Support was provided by the Wadsworth Center and the Division of Epidemiology epidemiology, field of medicine concerned with the study of epidemics, outbreaks of disease that affect large numbers of people. Epidemiologists, using sophisticated statistical analyses, field investigations, and complex laboratory techniques, investigate the cause , New York State Department of Health, the Department of Environmental Conservation, and the Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. . Dr. Bernard is assistant director of the Arbovirus Laboratory at the Wadsworth Center. Her major research interests are viral pathogenesis Viral pathogenesis is the study of how biological viruses cause diseases in their target hosts, usually carried out at the cellular or molecular level. It is a specialized field of study in virology. See also
 sz),n. in temperate temperate /tem·per·ate/ (tem´per-at) restrained; characterized by moderation; as a temperate bacteriophage, which infects but does not lyse its host. tem·per·ate adj. climates. (1) P. Bryon Backenson, Ivan Gotham, Yoichiro Hagiwara, Geraldine S The feminine form of the first name Gerald. Famous women named Geraldine include:
References (1.) Lanciotti RS, Roehrig JT, Deubel V, Smith J, Parker M, Steele K, et al. Origin of the West Nile virus West Nile virus, microorganism and the infection resulting from it, which typically produces no symptoms or a flulike condition. The virus is a flavivirus and is related to a number of viruses that cause encephalitis. responsible for an outbreak of encephalitis encephalitis (ĕnsĕf'əlī`təs), general term used to describe a diffuse inflammation of the brain and spinal cord, usually of viral origin, often transmitted by mosquitoes, in contrast to a bacterial infection of the meninges in the northeastern United States. Science 1999;286:2333-7. (2.) Centers for Disease Control and Prevention. Update: West Nile Virus activity--Eastern United States, 2000. MMWR MMWR Morbidity & Mortality Weekly Report Epidemiology A news bulletin published by the CDC, which provides epidemiologic data–eg, statistics on the incidence of AIDS, rabies, rubella, STDs and other communicable diseases, causes of mortality–eg, Morb Mortal mortal /mor·tal/ (mor´t'l) 1. subject to death, or destined to die. 2. fatal. mor·tal adj. 1. Liable or subject to death. 2. Wkly Rep 2000;49:1044-7. (3.) Centers for Disease Control and Prevention. Outbreak of West Nile-like viral encephalitis--New York, 1999. MMWR Morb Mortal Wkly Rep 1999;48:845-9. (4.) Office of Internationale des Epizooties. West Nile fever West Nile fever West Nile meningoencephalitis Infectious disease An acute, mosquito-borne flaviviral infection endemic–rarely, epidemic–in the Near East, Africa, former Soviet Union, India Clinical After a 3-6 day incubation, children present with a in Israel in geese. Disease Information 1999;12:166. (5.) Work TH, Hurlbut HS, Taylor RM. Isolation of West Nile virus from hooded crow hooded crow Noun a crow that has a grey body and black head, wings, and tail and rock pigeon pigeon, common name for members of the large family Columbidae, land birds, cosmopolitan in temperate and tropical regions, characterized by stout bodies, short necks, small heads, and thick, heavy plumage. in the Nile Delta The Nile Delta (Arabic:دلتا النيل) is the delta formed in Northern Egypt where the Nile River spreads . Proc Soc Exp Biol Med 1953;84:719-22. (6.) Steele KE, Linn linn n. Scots 1. A waterfall. 2. A steep ravine. [Scottish Gaelic linne, pool, waterfall.] MJ, Schoepp RJ, Komar N, Geisbert TW, Manduca RM, et al. Pathology of fatal West Nile virus infections in native and exotic birds The Exotic Birds was a pop music group formed in Cleveland, Ohio in 1983 by three Cleveland Institute of Music percussion students, Andy Kubiszewski, Tom Freer and Tim Adams. They wrote their own music and were described as synth pop, techno-pop and techno-dance. during the 1999 outbreak in New York City, New York. Vet Pathol 2000;37:208-24. (7.) Centers for Disease Control and Prevention. Update: West Nile virus encephalitis--New York, 1999. MMWR Morb Mortal Wkly Rep 1999;48:944-55. (8.) Turell MJ, O'Guinn M, Oliver J. Potential for New York mosquitoes to transmit West Nile virus. Am J Trop Med Hyg 2000;62:413-4. (9.) O'Guinn ML, Dohm DJ, Jones JW, Turell MJ. Potential mosquito vectors of West Nile virus in the United States. Am J Trop Med Hyg 2001;62:286. (10.) Reinert JF. New classification for the composite genus Aedes (Diptera: Culicidae: Aedini), elevation of subgenus subgenus /sub·ge·nus/ (sub´je-nus) a taxonomic category between a genus and a species. sub·ge·nus n. pl. sub·gen·e·ra A taxonomic category ranking between a genus and a species. Ochlerotatus to generic rank, reclassification Reclassification The process of changing the class of mutual funds once certain requirements have been met. These requirements are generally placed on load mutual funds. Reclassification is not considered to be a taxable event. of other subgenera, and notes on certain subgenera and species. J Am Mosq Control Assoc 2000;16:175-88. (11.) Shi P-Y, Kauffman EB, Ren P, Felton A, Tai JH, Dupuis II AP, et al. High throughput detection of West Nile virus RNA. J Clin Microbiol 2001;39:1264-71. (12.) Eidson M, Kramer LD, Stone W, Hagiwara Y, Schmit K, New York State West Nile Virus Avian Surveillance Team. Dead bird surveillance as an early warning system for West Nile virus. Emerg Infect infect /in·fect/ (in-fekt´) 1. to invade and produce infection in. 2. to transmit a pathogen or disease to. in·fect v. 1. Dis 2001;7:631-5. (13.) Centers for Disease Control and Prevention. Update: West Nile-like viral encephalitis--New York, 1999. MMWR Morb Mortal Wkly Rep 1999;48:890-2. (14.) Spielman A. Population structure in the Culex pipiens complex of mosquitos. Bull World Health Organ 1967;37:271-6. (15.) Hubalek Z, Halouzka J. West Nile fever--a reemerging mosquito-borne viral disease in Europe. Emerg Infect Dis 1999;5:643-50. (16.) Crans Crans is the name or part of the name of several places:
mass killing of animals or other pests. Implies complete destruction of the species or other group. Association 1964;51:50-8. (17.) Vaidyanathan R, Edman JD, Cooper LA, Scott TW. Vector competence of mosquitoes (Diptera: Culicidae) from Massachusetts for a sympatric sym·pat·ric adj. Ecology Occupying the same or overlapping geographic areas without interbreeding. Used of populations of closely related species. isolate of eastern equine encephalomyelitis Eastern equine encephalomyelitis see encephalomyelitis. virus. J Med Entomol 1997;34:346-52. (18.) Fonseca DM, Campbell SR, Crans WJ, Mogi M, Miyagi I, Toma T, et al. Aedes (Finlaya) japonicus (Diptera: Culicidae), a newly recognized mosquito in the United States: Analyses of genetic variation in the United States and putative Alleged; supposed; reputed. A putative father is the individual who is alleged to be the father of an illegitimate child. A putative marriage is one that has been contracted in Good Faith and pursuant to ignorance, by one or both parties, that certain source populations. J Med Entomol 2001;38:135-46. Kristen A. Bernard,(*) Joseph G. Maffei,(*) Susan A. Jones,(*) Elizabeth B. Kauffman,(*) Gregory D. Ebel,(*) Alan P. Dupuis II,(*) Kiet A. Ngo,(*) David C. Nicholas,(*) Donna M. Young,(*) Pei-Yong Shi,(*) Varuni L. Kulasekera,([dagger]) Millicent Eidson,(*) Dennis J. White,(*) Ward B. Stone,([double dagger double dagger n. A reference mark (  ) used in printing and writing. Also called diesis.Noun 1. ]) NY State West Nile Virus Surveillance Team,(1) and Laura D. Kramer(*) (*) New York State Department of Health, Albany, New York For other uses, see Albany. Albany is the capital of the State of New York and the county seat of Albany County. Albany lies 136 miles (219 km) north of New York City, and slightly to the south of the juncture of the Mohawk and Hudson Rivers. , USA; ([dagger]) New York City Department of Health, New York, New York, USA; and ([double dagger]) Department of Environmental Conservation, Albany, New York, USA Address for correspondence: Kristen A. Bernard, Arbovirus Laboratories, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY 12159; fax: 518-869-4530; e-mail: bernard@wadsworth.org |
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