Mosquito Surveillance and Polymerase Chain Reaction Detection of West Nile Virus, New York State.West Nile West Nile may refer to:
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. (NYC NYC abbr. New York City NYC New York City ) area during the summer and fall of 1999. Sixty-two human cases, 7 fatal, were documented. The New York New York, state, United States 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 Department of Health initiated a departmental effort to implement a statewide mosquito and virus surveillance system. During the 2000 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 surveillance season, we collected 317,676 mosquitoes, submitted 9,952 pools for virus testing, and detected 363 WN virus-positive pools by polymerase chain reaction polymerase chain reaction (pŏl`ĭmərās') (PCR), laboratory process in which a particular DNA segment from a mixture of DNA chains is rapidly replicated, producing a large, readily analyzed sample of a piece of DNA; the process is (PCR PCR polymerase chain reaction. PCR abbr. polymerase chain reaction Polymerase chain reaction (PCR) ). Eight species of mosquitoes were found infected. Our mosquito surveillance system complemented other surveillance systems in the state to identify relative risk for human exposure to WN virus. PCR WN virus-positive mosquitoes were detected in NYC and six counties in the lower Hudson River Hudson River River, New York, U.S. Originating in the Adirondack Mountains and flowing for about 315 mi (507 km) to New York City, it was named for Henry Hudson, who explored it in 1609. Dutch settlement of the Hudson valley began in 1629. Valley and metropolitan NYC area. Collective surveillance activities suggest that WN virus can disperse disperse /dis·perse/ (dis-pers´) to scatter the component parts, as of a tumor or the fine particles in a colloid system; also, the particles so dispersed. dis·perse v. 1. throughout the state and may impact local health jurisdictions in the state in future years. During the summer and fall of 1999, the metropolitan area of New York City witnessed an outbreak of human 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 caused by West Nile (WN) virus (1-3). This outbreak was the first evidence of WN virus infection in the Western Hemisphere Western Hemisphere Part of Earth comprising North and South America and the surrounding waters. Longitudes 20° W and 160° E are often considered its boundaries. (4-8) and resulted in 62 laboratory-confirmed human cases, 7 fatal (8). Evidence of WN virus infection was documented in mosquitoes, birds, horses, and humans, primarily in the New York, Connecticut, and New Jersey area of the northeastern 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. , with the southernmost distribution identified in a dead WN virus-positive crow in Baltimore, MD (9-11). Laboratory investigation into the likely geographic source of the WN virus strain identified in this outbreak indicated 99% homology homology (hōmŏl`əjē), in biology, the correspondence between structures of different species that is attributable to their evolutionary descent from a common ancestor. with a strain found in Israel in 1998 (5). Guidelines for WN virus surveillance developed in consultation with national experts were distributed by 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. (CDC See Control Data, century date change and Back Orifice. CDC - Control Data Corporation ) and included recommendations for disease prevention and control (12). Surveillance activities conducted in January and February 2000 for overwintering o·ver·win·ter·ing n. The persistence of an infectious agent in its vector for an extended period, as in the cooler winter months, during which the vector has no opportunity to be reinfected or to infect another host. 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. mosquitoes in New York City identified WN virus-infected specimens in underground hibernacula (13), indicating that there was a risk of virus maintenance in vector species and potential for reemergence as a human disease risk during the spring and summer months. Our report describes subsequent state and local agency efforts to establish, implement, and evaluate the mosquito and WN virus surveillance programs undertaken during 2000 to minimize risks for human and animal infection. Materials and Methods Local Health Department (LHD LHD abbr. Latin Litterarum Humaniorum Doctor (Doctor of Humanities; Doctor of Humane Letters) ) Response The New York State Department of Health (NYSDOH NYSDOH New York State Department of Health ) developed a system of mosquito pool allocations that would allow rapid detection of virus should WN virus appear anywhere in the area affected by the 1999 outbreak or in peripheral counties in the general metropolitan area or surrounding lower Hudson Valley
The Hudson Valley refers to the canyon of the Hudson River and its adjacent communities in New York State, generally from northern Westchester County northward to the cities of Albany and Troy. area. Based on data from the 1999 surveillance, initial priority was placed on mosquito species considered likely first indicators of virus circulation, primarily in the Culex genus. LHDs conducted early season larval larval 1. pertaining to larvae. 2. larvate. larval migrans see cutaneous and visceral larva migrans. surveillance and habitat descriptions, initiated habitat management and larval control in habitats where immature mosquitoes were present (focusing on container breeding, storm drain storm drain n. 1. A storm sewer. 2. A catch basin. , or catch basin catch basin n. 1. A receptacle at the entrance to a sewer designed to keep out large or obstructive matter. 2. A reservoir for collecting surface drainage or runoff. habitats), and developed a local database of these habitats. Adult mosquito surveillance activities could start at any time in the individual counties, and mosquito pools could be submitted to the NYSDOH Arbovirus Research Laboratory beginning the first week of June. The NYSDOH provided [CO.sub.2]-baited CDC miniature light traps (14) and gravid gravid /grav·id/ (grav´id) pregnant. grav·id adj. Carrying eggs or developing young. gra·vid mosquito traps (15) to LHDs to conduct adult mosquito surveillance. Anticipating a total statewide weekly submission of 400 mosquito pools (up to 50 mosquitoes/pool), we provided LHDs with a weekly pool allocation and scheduled day of submission for all mosquito pools to be tested for arboviruses arboviruses (ar´bōvī´r  sz),n. . The department also provided other surveillance supplies that LHDs would need to conduct initial mosquito surveillance activities or to enhance existing programs. We divided the surveillance equipment among the counties on the basis of 1) 1999 surveillance data and recognized geographic distribution of WN virus and 2) the anticipated geographic distribution of WN virus in the metropolitan NYC and lower Hudson Valley area during 2000. We also allocated pools for eastern equine encephalitis Eastern equine encephalitis A rare, sporadic, and aggressive enzootic infection by a single-stranded RNA Togavirus that primarily affects birds Vector Ornithophilic mosquito, Culiseta melanura surveillance conducted annually in Long Island and central New York Central New York is a term used to broadly describe the central region of New York State, roughly including the following counties and cities: Cayuga County – Auburn Cortland County – Cortland Madison County – Oneida . Mosquito pool allocations for 2000 were divided among the LHDs in NYC and the rest of the state on the basis of human population density and distance from the 1999 epicenter. Weekly pool allocations ranged from 90 pools for NYC, 45 pools for each county on Long Island, 40 pools for Westchester County, and 10-15 pools for counties further upstate that were conducting adult mosquito surveillance. Mosquitoes submitted for virus testing arrived at the Arbovirus Research Laboratory on a weekly basis; some counties submitted specimens midweek and others at the end of the week to split the initial 400-pool weekly load. Mosquito pools contained specimens from a single species (or combined species such as Cx. pipiens and Cx. restuans) collected at a single site during the week. In some cases where numbers were below the target of 50 specimens per pool, collections from 2 sequential weeks or from closely adjacent sites were combined. Although the NYSDOH initially requested separation, it is unlikely that all counties effectively removed all blood-fed or gravid females from weekly collections. Therefore, some pools positive by polymerase chain reaction (PCR) may have contained blood-fed or gravid mosquitoes. Mosquito pools submitted to the Arbovirus Research Laboratory were tested for viral 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 by reverse transcription reverse transcription n. The process by which DNA is synthesized from an RNA template. (RT)-PCR techniques following established protocols and reported as described (16). Briefly, mosquitoes were tested by TaqMan RT-PCR RT-PCR reverse transcriptase-polymerase chain reaction. See PCR1. with two primer-probe sets. Virus isolation attempts in 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 followed the detection of PCR-positive pools, as described (16). State Analysis of Surveillance Data Surveillance data related to adult mosquito populations, adult mosquito pool submissions for virus testing, and laboratory test results (as well as bird, animal, and human data) were entered into the NYSDOH Health Information Network, a secure statewide health agency communication network. These surveillance data were maintained on a daily basis and available to NYSDOH and the contributing LHD. Local agency data were held confidential for 24 hours Adv. 1. for 24 hours - without stopping; "she worked around the clock" around the clock, round the clock before all other LHDs were provided summary information. All LHDs were responsible for the entry of mosquito surveillance data in the Health Information Network, as described. All surveillance mechanisms (mosquito, bird, animal, and human) provided data for this secure database. Program and laboratory review of the surveillance database, as well as laboratory entry of virus detection results, provided a current picture of mosquito populations and a virus infection registry of statewide data. When used fully and properly by the LHDs, mosquito population dynamics Population dynamics is the study of marginal and long-term changes in the numbers, individual weights and age composition of individuals in one or several populations, and biological and environmental processes influencing those changes. , rates, and location of arbovirus activity could be derived from regular review of this comprehensive database. All analyses conducted for this report were developed through the summary of the information extracted from that network. Results Mosquito Surveillance Counties conducting adult mosquito surveillance during 2000 along with a summary of their general surveillance efforts are listed in Table 1. Although 26 counties collected and submitted pools of mosquitoes for virus testing (Figure 1) PCR-positive mosquitoes were found only in the five NYC boroughs, both counties on Long Island, and four counties in the lower Hudson River Valley. Figure 2 provides the weekly numbers of mosquitoes collected by genus through the 26-week collection season from May 13 to November 4, 2000. A total of 317,676 mosquitoes were collected: 192,538 (60.6%) Culex spp., 86,034 (27.1%) Aedes (or Ochlerotatus) spp., and 39,104 (12.3%) other species. LHDs collected 28 species of mosquitoes during the 2000 adult mosquito surveillance season (3 Aedes spp., 4 Anopheles Anopheles: see mosquito. spp., 1 Coquillettidia sp., 4 Culex spp., 2 Culiseta spp., 11 Ochlerotatus spp., 1 Orthopodomyia sp., 1 Psorophora sp., and 1 Uranotaenia sp.). Of the 9,952 pools submitted for testing, 5,851 (58.8%) were Culex spp., 3,072 (30.9%) were Aedes or Ochlerotatus spp., and 1,029 (10.3%) were other species. Despite the original agreement with LHDs for a maximum weekly submission of 400 pools, submissions exceeded the maximum during 11 weeks of the season, with a peak of 1,200 pools submitted the week of August 5. Laboratory protocols were initially established at a maximum of 100 mosquitoes per pool, but that figure was reduced to 50 mosquitoes per pool in May to enhance the ability to detect virus. [ILLUSTRATION OMITTED] [GRAPH OMITTED]
Table 1. Local health department mosquito surveillance programs
No. of
mosquitoes No. of
No. of submitted PCR-
Local health trap for virus positive
department nights testing pools
Albany 203 2,305 0
Broome 81 235 0
Cattaraugus 176 1,320 0
Columbia 369 1,161 1
Cortland 47 88 0
Dutchess 1,439 8,319 0
Erie 45 512 0
Madison 58 2,310 0
Monroe 136 1,156 0
Nassau 1,771 25,543 7
Niagara 104 1,697 0
Oneida 726 2,173 0
Onondaga 566 15,599 0
Orange 1,188 17,091 4
Oswego 1,555 12,417 0
Putnam 1,270 10,200 0
Rockland 2,037 28,623 47
Suffolk 960 77,955 120
Ulster 435 8,234 0
Warren 19 423 0
Westchester 2,505 24,478 13
New York City 2,850(a) 75,837 171
Brooklyn 12
Bronx 6
Manhattan 17
Queens 5
Staten Is. 131
Statewide 18,540 317,676 363
(a) Estimated.
PCR = polymerase chain reaction.
Virus Surveillance in Mosquitoes Quantified summary data related to virus distribution by county and by mosquito species are provided in Table 2. NYSDOH surveillance and laboratory testing activities during 2000 led to the identification of 363 PCR WN virus-positive mosquito pools. Results from virus isolation attempts on these PCR-positive pools are included in Table 3. We are also aware of the detection of a single PCR-positive pool of Culex pipiens/restuans collected by U.S. Army Center for Health Promotion and Preventive Medicine preventive medicine, branch of medicine dealing with the prevention of disease and the maintenance of good health practices. Until recently preventive medicine was largely the domain of the U.S. staff in Brooklyn (B. Pagac, pers. comm.; data not included). Although NYC and Long Island LHDs submitted only 5,324 (53%) of the 9,952 total mosquito pools, 298 (82%) of 363 PCR WN virus-positive pools were collected in these counties. Only 65 (18%) of the 363 PCR WN virus-positive pools were identified in four counties north of NYC and Long Island, despite accounting for 26% (2,549/9,952) of the total pools submitted. Most PCR-positive pools (72%, 47/65) from upstate were from Rockland County. Similarly, 341 (94%) of the 363 PCR-positive pools were Culex mosquitoes, primarily in the group of Cx. pipiens/restuans mosquitoes that were not separated because of loss of morphologic characteristics during collection or natural aging. Although we found 79 pools of Cx. pipiens PCR positive for WN virus, none of 238 pools of Cx. restuans were positive. Twenty PCR WN virus-positive pools of Aedes or Ochlerotatus species mosquitoes were identified, primarily from Ae. vexans (10 pools) and Oc. japonicus (5 pools).
Table 2. Local health department reports of West Nile virus specimens
that were positive by polymerase chain reaction (PCR)
% of total
PCR-positive PCR-positive
pools/pools pools tested
submitted (% pos) statewide
By county
Brooklyn 12/281 (4.3) 3.3
Staten Island 131/935 (14.0) 36.1
Queens 5/683 (0.7) 1.4
Manhattan 17/262 (6.5) 4.7
Bronx 6/298 (2.0) 1.6
Nassau 7/821 (0.9) 1.9
Suffolk 120/2,044 (5.9) 33.1
Westchester 13/872 (1.5) 3.6
Rockland 47/1,096 (4.3) 12.9
Orange 4/529 (0.8) 1.1
Columbia 1/52 (1.9) 0.3
Total 363/7,873 (4.6) 100.0
By species
Culex pipiens 79/1,119 (7.1) 21.8
Cx. restuans 0/238 (0) 0
Cx. pip/res 212/3,746 (5.7) 58.4
Cx. salinarius 31/501 (6.2) 8.5
Culex species 19/232 (8.2) 5.2
Ochlerotatus japonicus 5/526 (1.0) 1.4
Oc. triseriatus 3/407 (0.7) 0.8
Aedes vexans 10/1,182 (0.8) 2.7
Oc. cantator 1/87 (1.1) 0.3
Aedes species 1/73 (1.4) 0.3
Anopheles punctipennis 1/54 (1.8) 0.3
Psorophora ferox 1/16 (6.2) 0.3
Total 363/8,181 (4.4) 100.0
Table 3. Comparison of West Nile virus detection in mosquito pools
positive by polymerase chain reaction (PCR) tests and isolation in
Vero cells
No. pools
PCR+/no.
No. pools mosquitoes
Species (indiv) tested tested (MIR)
Culex pipiens/restuans 3,746 (130,745) 212/130,745 (1.6)
Cx. pipiens 1,119 (30,818) 79/30,818 (2.6)
Cx. salinarius 501 (20,236) 31/20,236 (1.5)
Aedes vexans 1,182 (35,010) 10/35,010 (0.3)
Ochlerotatus japonicus 526 (7,209) 5/7,209 (0.7)
Culex spp. 232 (6,466) 19/6,466 (2.9)
Oc. triseriatus 407 (9,278) 3/9,278 (0.3)
Oc. cantator 87 (2,608) 1/2,608 (0.4)
Aedes/Ochlerotatus spp. 73 (1,365) 1/1,365 (0.7)
Anopheles punctipennis 54 (456) 1/456 (2.2)
Psorophora ferox 16 (225) 1/225 (4.4)
PCR+ (indiv) PCR+ (indiv)
and and
Species culture + culture -
Culex pipiens/restuans 61 (2,555) 83 (4,124)
Cx. pipiens 25 (630) 35 (1,413)
Cx. salinarius 13 (486) 13 (666)
Aedes vexans 1 (11) 8 (252)
Ochlerotatusjaponicus 0 (0) 5 (36)
Culex spp. 9 (296) 4 (187)
Oc. triseriatus 1 (16) 2 (51)
Oc. cantator 0 (0) 1 (10)
Aedes/Ochlerotatus spp. 0 (0) 0 (0)
Anopheles punctipennis 0 (0) 1 (5)
Psorophora ferox 1 (10) 0 (0)
PCR+ (indiv)
and culture
Species not done
Culex pipiens/restuans 68 (2,507)
Cx. pipiens 19 (698)
Cx. salinarius 5 (190)
Aedes vexans 1 (21)
Ochlerotatusjaponicus 0 (0)
Culex spp. 6 (300)
Oc. triseriatus 0 (0)
Oc. cantator 0 (0)
Aedes/Ochlerotatus spp. 1 (20)
Anopheles punctipennis 0 (0)
Psorophora ferox 0 (0)
Temporal analysis of mosquito-based WN virus surveillance is illustrated in Figure 3 for all mosquito species (or groups) during the 2000 season. The first PCR evidence of WN virus infection in mosquitoes occurred in specimens collected the week of July 1, 2000, with one WN virus-positive pool each in Cx. pipiens collected in Richmond County Richmond County may refer to multiple places: In Canada:
WNV World Net Visions was identified by PCR in eight mosquito species from a wide geographic area of Long Island and the lower Hudson River Valley, north to Columbia County Columbia County is the name of eight counties in the United States:
Figure 3. Temporal detection of West Nile virus infection
in mosquito species submitted for testing by week of collection,
New York, 2000.
Mosquito Species
Ochlerotatus cantator
Aedes species unspec.
Psorophora ferox
Anopheles punctipennis
Aedes vexans
Ochlerotatus triseriatus
Culex species unspec.
Culex salinarius
Culex pipiens-restuans
Ochlerotatus-japonicus
Culex pipiens
Positive pools 0 0 0 0 0 0 0
Total pools 42 11 22 316 249 310 408
Week starting M M M J J J J
A A A U U U U
Y Y Y N N N N
1 2 2 3 1 1 2
(*) number of positive
pools 3 0 7 0 7 4
Mosquito Species
Ochlerotatus cantator
Aedes species unspec.
Psorophora ferox
Anopheles punctipennis
Aedes vexans 3 1
Ochlerotatus triseriatus 2
Culex species unspec. 14 1
Culex salinarius 3 8 1 7
Culex pipiens-restuans 12 46 11 14 33 16
Ochlerotatus-japonicus 1 1 1
Culex pipiens 1 1 7 8 14 11
Positive pools 2 13 51 26 23 73 29
Total pools 357 513 708 833 490 ### 714
Week starting J J J J J A A
U U U U U U U
L L L L L G G
1 8 1 2 2 5 1
(*) number of positive
pools 5 2 9 2
Mosquito Species
Ochlerotatus cantator 1(*)
Aedes species unspec. 1
Psorophora ferox 1
Anopheles punctipennis 1
Aedes vexans 3 1 2
Ochlerotatus triseriatus 1
Culex species unspec. 3 1
Culex salinarius 4 6 1 1
Culex pipiens-restuans 27 22 3 19 5
Ochlerotatus-japonicus 2
Culex pipiens 9 13 6 6 3
Positive pools 40 48 13 29 12 0
Total pools 614 847 383 562 567 178
Week starting A A S S S S
U U E E E E
G G P P P P
1 2 2 9 1 2
(*) number of positive
pools 9 6 6 3
Mosquito Species
Ochlerotatus cantator
Aedes species unspec.
Psorophora ferox
Anopheles punctipennis
Aedes vexans
Ochlerotatus triseriatus
Culex species unspec.
Culex salinarius
Culex pipiens-restuans 2 1 1
Ochlerotatus-japonicus
Culex pipiens
Positive pools 2 1 1 0 0
Total pools 378 65 86 57 17
Week starting S O O O O
E C C C C
P T T T T
3 7 1 2 2
(*) number of positive
pools 0 4 1 8
We calculated trap-type productivity by species for the six most abundant mosquito species collected statewide during 2000. Dry ice-baited CDC light traps captured 98% of the Ae. vexans, 83% of the Oc. triseriatus, 77% of the Cx. salinarius, 55% of both total Cx. pipiens and Cx. pipiens/ restuans combined, and 21% of the Oc. japonicus. The only species collected in predominantly greater numbers by the gravid traps was Oc. japonicus (76% of total collections). Although gravid traps collected only 30% of the total number of mosquito pools submitted for virus testing during 2000, 56% of the PCR-positive pools came from gravid trap collections. None of the mosquito pools (n=135) from diurnal diurnal /di·ur·nal/ (di-er´nal) pertaining to or occurring during the daytime, or period of light. di·ur·nal adj. 1. Having a 24-hour period or cycle; daily. 2. resting boxes or aspiration collections (n=11) had evidence of virus infection. However, 205 (6.9%) of 2,957 pools from gravid traps and 158 (2.3%) of 6,828 pools from CDC light traps were PCR positive for WN virus. Since mosquitoes attracted to gravid traps for oviposition oviposition the act of laying or depositing eggs. would have fed on a host several days previously, a widespread presence of infected hosts could have resulted in these mosquitoes being more likely to acquire virus, thereby explaining the threefold difference in PCR-positive rates in gravid trap collections. We also investigated the contribution of species minimum infection ratios (MIRs) per 1,000 mosquitoes throughout the season. MIRs (based on PCR-positive tests) were evaluated by individual pool sizes for each species and by analysis of weekly and seasonal aggregated species data within and among LHDs. Figures 4 and 5 illustrate the weekly MIRs by species for each genus (Aedes, Ochlerotatus, and Culex) through the adult mosquito surveillance season in counties that had evidence of human or 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 (8). (These figures represent the recapitulation recapitulation, theory, stated as the biogenetic law by E. H. Haeckel, that the embryological development of the individual repeats the stages in the evolutionary development of the species. of results after all laboratory data were completed.) WN virus infection (confirmed by PCR) in Culex spp. began in early July and continued through the summer, concurrent with human case onsets; weekly MIRs ranged from 1 to 3.5 per 1,000, with a subsequent peak in early October. Although 80 to 100 pools of Aedes or Ochlerotatus were submitted during June and July, the PCR WN virus-positive Oc. japonicus in early July resulted in relatively high genus-specific MIRs. A second peak of elevated Aedes and Ochlerotatus MIRs occurred in late August and September, concurrent with an observed peak of equine cases. Further review of these data from counties where human or equine cases occurred, using MIR and multifactorial multifactorial /mul·ti·fac·to·ri·al/ (mul?te-fak-tor´e-al) 1. of or pertaining to, or arising through the action of many factors. 2. analyses, is required. [GRAPHS OMITTED] By the end of the 2000 surveillance season in New York, PCR WN virus-positive specimens were detected throughout the state (Figure 6). While human disease was restricted to four NYC boroughs (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. , Brooklyn, Manhattan, and Queens), PCR evidence of WN virus infection in mosquitoes was detected in all five NYC boroughs, four adjacent metropolitan counties, and two counties further upstate. Evidence of infection in avian avian /avi·an/ (a´ve-an) of or pertaining to birds. a·vi·an adj. Of, relating to, or characteristic of birds. hosts, however, was detected throughout the state (except for Chenango County) (17). Despite the submission of 2,660 pools of primary vector species from 17 upstate counties outside the immediate metropolitan area, we detected PCR evidence of WN virus only in Orange (two pools of Oc. japonicus and one each of Cx. pipiens and Cx. pipiens/restuans) and Columbia (one pool of Oc. japonicus) counties. However, MIRs generally reflected the pattern of human cases and dead crow sightings
Sightings was a paranormal-themed television program that was first broadcast as an hour special entitled "UFO Report: Sightings" in October 1991. per square mile (17) in three categories: 1) a combination of high number of human cases, dead crow sightings per square mile, and an overall seasonal MIR of 5.27/1,000 tested in Staten Island; 2) a small number of human cases, moderate number of dead crow sightings per square mile, and seasonal MIRs ranging from 0.18 to 2.36/1,000 for counties in and near NYC; and 3) no human cases, low number of dead crow sightings per square mile, and seasonal MIRs ranging from 0 to 0.86/1,000 for upstate counties (Figure 6). Documented WN virus transmission to humans and horses was limited to a much smaller geographic area of New York State, and, over the last two seasons, has included only NYC, Long Island, Westchester County, and Orange County (roughly 50 miles north of NYC). [ILLUSTRATION OMITTED] Discussion Review of specific local human and mosquito population data will be addressed in separate publications. Our work summarizes statewide surveillance components and identifies some potential flaws due to the geographic aggregation of data. In addition, surveillance may not have been uniformly applied across all municipalities. However, review of these initial surveillance data will lead investigators to design research projects that will better enable the public health community to answer questions that continue to arise (e.g., regarding virus transmission, host pathogenicity pathogenicity the ability of a pathogenic agent to produce disease in a host. See also virulence. , immunology immunology, branch of medicine that studies the response of organisms to foreign substances, e.g., viruses, bacteria, and bacterial toxins (see immunity). Immunologists study the tissues and organs of the immune system (bone marrow, spleen, tonsils, thymus, lymphatic , interventions, sociologic aspects, and vaccination or treatment issues). There may be some risk of faulty interpretation in a retrospective review retrospective review, a posttreatment assessment of services on a case-by-case or aggregate basis after the services have been performed. of statewide field and laboratory data. In addition, we have not fully evaluated the potential effect of mosquito control operations on overall mosquito populations. However, these data provide necessary baseline information related to virus ecology and infection dynamics. The detection of MIRs associated with individual mosquito species may help public health agencies and academic institutions to focus on specific species with high levels of vectorial capacity (18). The surveillance system in New York State during 2000 led to the submission of [is greater than] 300,000 mosquitoes in almost 10,000 pools for arbovirus screening; most were derived from LHDs that had not previously conducted mosquito or arbovirus surveillance. These efforts required regular internal discussions on laboratory capacity, steps that could be taken to improve it, and proper use of laboratory capacity to answer both routine surveillance and research demands on limited resources. Although there is an inherent procedural lag between mosquito collection and the availability of laboratory results, this initial analysis supports the natural presence of WN virus PCR-positive Culex, Aedes, and Ochlerotatus mosquitoes 2 weeks before onset of human illness. In addition, peak Culex infection during the period of prominent human infection appears to be associated with a peak of PCR WN virus-positive Aedes and Ochlerotatus immediately before and during the onsets of equine cases, which occurred several weeks after the peak of human onsets. However, laboratory confirmation of positivity for all virus surveillance mechanisms (mosquitoes, birds, humans, and horses) usually lagged behind specimen collection or onset dates by several weeks. In addition, infection dates for human and horse cases are likely to precede onset dates by several days to weeks, depending on the individual incubation periods incubation period n. 1. See latent period. 2. See incubative stage. Incubation period . Interpretation of the influence of trap type on yield of PCR-positive pools is complicated by the potential for detecting virus that may have been present in the host on which individual mosquitoes may have fed. Ideally, blood-fed or gravid mosquitoes should be separated from unfed females before laboratory testing. Clearly, however, a blood-fed female mosquito one week will become a host-seeking female a week or two later, and full understanding of the transmission dynamics of WN virus may require this separation, along with specific determination of host meals. Data indicate that agencies with limited budgets may be able to identify the local presence and natural circulation of WN virus more efficiently by focusing on gravid trap-based programs. Initial analyses of MIRs associated with individual mosquito species indicate that certain species, especially Cx. salinarius, Cx. pipiens, Oc. japonicus and Oc. triseriatus, may play major roles in the natural transmission of WN virus among animal hosts. Several of these species (or species complexes) may be involved with an as-yet-unknown reservoir host reservoir host n. A host that serves as a source of infection and potential reinfection of humans and as a means of sustaining a parasite when it is not infecting humans. capable of maintaining the virus in the absence of overt host pathogenicity. Note, however, that no infectious virus was isolated in approximately half of the mosquito pools tested with detectable RNA. WN virus RNA was detected in five pools of Oc. japonicus, for example, but no infectious virus was isolated from these mosquitoes (19). The level of infectious virus may have been too low to be detected and may have increased with further extrinsic EVIDENCE, EXTRINSIC. External evidence, or that which is not contained in the body of an agreement, contract, and the like. 2. It is a general rule that extrinsic evidence cannot be admitted to contradict, explain, vary or change the terms of a contract or of a incubation, complicating the interpretation of MIRs. The interrelationships, ecologic niches, and host-meal preferences, for example, of the various 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. may play a major role in the entire ecology of the virus now that it has been introduced to a completely naive hemisphere. In addition, the MIRs of Culex and other species associated with the apparently bimodal bi·mod·al adj. 1. Having or exhibiting two contrasting modes or forms: "American supermarket shopping shows bimodal behavior human and equine case distribution may point to a complex mosquito vector relationship not only among the various Culex species, especially Cx. salinarius and Cx. pipiens and perhaps Cx. restuans, but also with other more prominent mammal-feeding species such as Ae. vexans, Oc. triseriatus, and Oc. japonicus. What will happen as this virus continues to spread into other areas of North or Central America Central America, narrow, southernmost region (c.202,200 sq mi/523,698 sq km) of North America, linked to South America at Colombia. It separates the Caribbean from the Pacific. where aggressive and more numerous mammal-feeding species exist? How will human disease risks increase if Oc. sollicitans, Cx. tarsalis, Ae. aegypti, or Anopheles species become competent vectors under normal field conditions? Are non-mosquito vectors (such as ticks, mites, or black flies) contributing to the total ecologic cycle (e.g., transmission and overwintering) of this virus in nature? Intervention programs must be established that can account for answers to these questions and maintain our original goals of minimizing the risks for human and other animal infections. Given the recognized ability of WN virus to survive in hibernating mosquitoes in the northeastern United States (20) and the current distribution of the virus in birds, 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. , and mosquitoes along the Atlantic seaboard, public health agencies in affected and neighboring neigh·bor n. 1. One who lives near or next to another. 2. A person, place, or thing adjacent to or located near another. 3. A fellow human. 4. Used as a form of familiar address. v. states should be prepared to address the emergence of this virus in their jurisdictions in future years. Another major goal that public health agencies must face is developing a more timely virus surveillance system. This system should allow detection of the virus in mosquito or bird host systems in sufficient time to permit an appropriate intervention to minimize or prevent further 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. infection. Our current surveillance and laboratory testing systems have inherent time lags that may preclude our ability to intervene against infected adult mosquitoes on a timely basis, before humans are exposed. Acknowledgments We gratefully acknowledge Y. Hagiwara, N. Panebianco, J. Rososki, J. Napoli, R. Falco, T. Daniels, L. Grady, C. Huang, M. Fage, J. Gebbia, S. Bamberger, N. Pardanani, M. Martin, S. Trock, B. Wallace, P. Smith, D. Morse, D. Whalen, and A. Novello. Dr. White is the Director of the Arthropod-Borne Disease Program and Director of the Tick-Borne Disease Tick-borne disease A disease that is spread to animals by the bite of an infected tick. Mentioned in: Ehrlichiosis Institute of the New York State Department of Health and Associate Professor, School of Public Health, State University of New York (body) State University of New York - (SUNY) The public university system of New York State, USA, with campuses throughout the state. at Albany. His current research interests include field ecology and modeling of vector-borne diseases vector-borne disease Infectious diseases Any infection, usually transmitted by insects–eg, ticks–eg, Lyme disease, Rocky Mountain spotted fever, ehrlichiosis, Colorado tick fever; mosquitos–eg, California-or La Crosse, St Louis, Eastern, Western . References (1.) Centers for Disease Control and Prevention. Outbreak of West Nile-like viral encephalitis--New York, 1999. 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 Wkly Rep 1999;48:845-9. (2.) Centers for Disease Control and Prevention. Update: 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. encephalitis--New York, 1999. MMWR Morb Mortal Wkly Rep 1999;48:944-6,955. (3.) Centers for Disease Control and Prevention. Update: West Nile-like viral encephalitis--New York, 1999. MMWR Morb Mortal Wkly Rep 1999;48:,$90-2. (4.) Hubalek Z, Halouzka J. West Nile fever--a reemerging mosquito-borne viral disease in Europe. Emerg Infect Dis 1999;5:643-50. (5.) Lanciotti RS, Roehrig JT, Duebel V, Smith J, Parker M, Steele K, et al. Origin of the West Nile virus responsible for an outbreak of encephalitis in the northeastern United States. Science 1999;286:2333-7. (6.) Hayes CG. 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: Monath RD, editor. The arboviruses: epidemiology and ecology. Boca Raton Boca Raton (bō`kə rətōn`), city (1990 pop. 61,492), Palm Beach co., SE Fla., on the Atlantic; inc. 1925. Boca Raton is a popular resort and retirement community that experienced significant industrial development in the 1970s and 80s. (FL): CRC (Cyclical Redundancy Checking) An error checking technique used to ensure the accuracy of transmitting digital data. The transmitted messages are divided into predetermined lengths which, used as dividends, are divided by a fixed divisor. Press, Inc.; 1989. (7.) Savage HM, Ceianu C, Nicolescu G, Karabatsos N, Lanciotti R, Vladimirescu A, et al. Entomologic en·to·mol·o·gy n. The scientific study of insects. en  to·mo·log and avian investigations of an
epidemic of West Nile fever in Romania in 1996, with serologic se·rol·o·gy n. pl. se·rol·o·gies 1. The science that deals with the properties and reactions of serums, especially blood serum. 2. and molecular characterization of a virus isolate from mosquitoes. Am J Trop Med Hyg 1999;61:600-11. (8.) Centers for Disease Control and Prevention. Update: West Nile virus activity--eastern United States, 2000. MMWR Morb Mortal Wkly Rep 2000;49:1044-7. (9.) Centers for Disease Control and Prevention. West Nile virus activity--New York and New Jersey, 2000. MMWR Morb Mortal Wkly Rep 2000;49:640-2. (10.) Anderson JF, Andreadis TG, Vossbrinck CR, Tirrell S, Wakem EM, French RA, et al. Isolation of West Nile virus from mosquitoes, crows and Cooper's hawk in Connecticut. Science 1999;286:2331-3. (11.) Komar N. West Nile viral encephalitis viral encephalitis Viral meningoencephalitis Neurology, infectious disease A general term for nonpurulent–'aseptic' viral infection of the CNS Etiology Coxsackie A and B–eg, A7, enterovirus 71, herpes simplex, etc Clinical If the viral load is extreme, . Rev Sci Tech 2000;19:166-76. (12.) Centers for Disease Control and Prevention. Guidelines for surveillance, prevention, and control of West Nile virus infection--United States. MMWR Morb Mortal Wkly Rep 2000;49:25-8. (13.) Nasci RS, White DJ, Stifling H, Oliver J, Daniels TJ, Falco RS, et al. West Nile virus isolates from mosquitoes in New York and New Jersey, 1999. Emerg Infect Dis 2001;7:626-30. (14.) Newhouse VR, Chamberlain RW, Johnston JF, Sudia WD. Use of dry ice to increase mosquito catches of the CDC miniature light trap. Mosquito News 1966;26:30-5. (15.) Reiter P. A portable, battery-powered trap for collecting gravid Culex mosquitoes. Mosquito News 1983;43:496-8. (16.) Shi P-Y, Kauffman EB, Ren P, Felten A, Tai JH, Dupuis AP II, et al. High throughput detection of West Nile virus RNA. J Clin Microbiol 2001;39:1264-71. (17.) Eidson M, Miller J, Kramer L, Cherry B, Hagiwara Y, and the WNV Bird Mortality Analysis Group. Dead crow densities and human cases of West Nile virus, New York State, 1999. Emerg Infect Dis 2001;7:662-4. (18.) Spielman A, James AA. Transmission of vector-borne disease. In: Warren KS, Mahmood AAF AAF abbr. Army Air Forces , editors. Tropical and geographical medicine. 2nd ed. New York: McGraw Hill; 1990. p. 146-59. (19.) Bernard KA, Maffei JG, Jones SA, Kauffman EB, Ebel GD, Dupuis AP, et al. West Nile virus infection in birds and mosquitoes, New York State, 2000. Emerg Infect Dis 2001;7:679-85. (20.) Nasci RS, Savage HM, White DJ, Miller JR, Cropp BC, Godsey MS, et al. West Nile virus in overwintering Culex mosquitoes, New York City, 2000. Emerg Infect Dis 2001;7:742-4. Dennis J. White,(*) Laura D. Kramer,(*) P. Bryon Backenson,(*) Gary Lukacik,(*) Geraldine Johnson,(*) JoAnne Oliver,(*) John J. Howard,(*) Robert G. Means,(*) Millicent Eidson,(*) Ivan Gotham,(*) Varuni Kulasekera,([dagger]) Scott Campbell,([double dagger double dagger n. A reference mark (  ) used in printing and writing. Also called diesis.Noun 1. ]) the Arbovirus Research Laboratory(1) and the Statewide West Nile Virus Response Teams(2) (*) 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]) City of New York Department of Health, New York, New York, USA; and ([double dagger]) Suffolk County Department of Health Services Department of Health Services may refer to:
Yaphank is a community in the south part of the Town of Brookhaven. , USA (1) E.B. Kauffman, K.A. Bernard, G.D. Ebel, P-Y. Shi, S.A. Jones, A.P. Dupuis II, J. Maffei, K.A. Ngo, D.C. Nicholas, and D. Young. (2) J. Miller, City of New York Department of Health; D. Ninivaggi, Suffolk County Department of Health Services; C. Hodgeman, G. Terrillion, Nassau County Nassau County is the name of two counties in the United States of America:
Address for correspondence: Dennis J. White, Director, Arthropodborne Disease Program, New York State Department of Health, 632 Corning Tower, Empire State Plaza The Governor Nelson A. Rockefeller Empire State Plaza (commonly known as simply the Empire State Plaza and less formally as The South Mall) is a complex of several state government buildings in downtown Albany, New York. , Albany, New York 12237, USA; fax: 518-473-1708; e-mail: djw05@health.state.ny.us |
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