Historical Summary
By State and Country
Information is current as of the date indicated for each entry
Summaries are accurate through 2002, with news posted only on occasion since 2002.
Alaska, Arizona, Hawaii, Nevada, Oregon and Utah are the only states where WNV has not been detected.
Detection of WNV in wild birds (such as crows) and sentinel captive birds (such as chickens) is an important early surveillance tool to indicate the presence of WNV in a geographical area. Cumulative counts of WNV-positive birds have ceased to be a useful indicator of WNV prevalence, however, because reports of dead birds are handled differently in different places. Many health districts have discontinued bird surveillance, collection and/or testing once WNV-positive birds are confirmed in an area; most districts have only monitored crows (and corvid relatives), while some have also monitored other species. Far more knowledge about the significance and impact of WNV on bird populations can be derived from controlled studies than from simply tallying numbers of WNV-positive birds. Therefore ERAP is not maintaining currency of these data in the state-by-state summaries (below).
In 2001, WNV was detected in 27 US states (and Washington DC, as well as in Romania, Israel, Canada, and the Cayman Islands in the Caribbean. US states included: Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, Missouri , New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Tennessee, Virginia, Wisconsin.
United States:
AL AZ AR CA CO CT DE FL GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA DC WV WI WY
Other Countries:
Canada Caribbean Israel Mexico Romania
AL AZ AR CA CO CT DE FL GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA DC WV WI WY
Other Countries:
Canada Caribbean Israel Mexico Romania
- Alabama: (Website checked Dec 19 2002) In 2002 WNV was detected in at least 63 of the 67 counties in Alabama, though it was believed to be present in all counties. There were 46 human cases (3 fatalities) in 2002, the first of which was in SE AL (ann Aug 7). As of Nov 8 2002, 63 mosquito pools, 577 birds and 88 horses were confirmed WNV-positive. The first case in 2002 was a bird from Coffee Co (SE AL) found May 29 in downtown Enterprise. The first case of WNV in AL was detected 3 months earlier in 2002 than in 2001. At the time, state veterinarian Dr. Bill Johnston said "Considering that southeast Alabama has suffered a drought this year, finding WNV activity this early should serve as a red flag" [More].
In 2001, a 44 year-old man was the first ever human fatality in AL and the fifth fatality in the nation in 2001 (infected late Aug 2001, died Oct 30). The first equine cases were two stablemates in Dale Co (SE AL) that became ill late Aug (ann by USDA APHIS Sept 14 2001). In 2001, there were a total of 4 WNV-positive horses in 3 counties (USDA APHIS). WNV in birds was first confirmed Aug 27 2001 (from Jefferson Co, center of the state and the location of Alabama's largest city, Birmingham). In 2001 WNV was confirmed in 59 birds from 13 counties, primarily Jefferson (35) and Montgmery (9) [More].
[Alabama Dept of Public Health News Releases: http://www.adph.org/newsreleases/] - Arizona: (AZ News checked Dec 19 2002) In 2002, active surveillance was conducted May-Oct without detecting WNV, except in 3 human and 1 equine case that were likely travel-related (i.e., not contracted in AZ): 1 following travel to Missouri and Indiana, another to Michigan, and a third after travel to Ohio ann in Sept . The horse tested WNV-positive in late Aug, likely contracting the virus in Minnesota. As of Oct 9, the ADHS State Health Laboratory had tested more than 600 mosquito pools; 1,200 blood samples from sentinel chicken flocks placed strategically across the state; and more than 100 human specimens. All were negative, except for the three imported human cases.
[Arizona Dept Health Services News: http://www.hs.state.az.us/news/; State Public Health Hotline (602) 364-4500 or (800) 314-9243] - Arkansas: (Updated Dec 19 2002) In 2002, Arkansas Dept of Health confirmed 29 human cases (while CDC only reported 25) with 16 suspect cases pending test results from CDC. The first human case was from south central AR (ann Aug 28 2002).
The first case of WNV in 2002 was found June 22 in a bird in St Francis Co (E AR). As of Nov 11 2002, 498 birds in 67 of AR's 75 counties were confirmed WNV-positive. As of Dec 5 2002, 148 horses (55 fatalities) were confirmed WNV-positive.
The first ever WNV case was reported Oct 4 2001 in a dead blue jay in Union Co. In total 4 WNV-positive birds were found in 3 counties in 2001: Union Co (S AR on LA border), Benton Co (NW AR, on OK and MO borders), and Sebastian Co (W AR on OK border).
[Healthy Arkansas News Releases: http://www.healthyarkansas.com/news/news.html] - California (Website checked Dec 19 2002) California Dept Heath Services confirmed Sept 12 2002 that a Los Angeles woman was exposed to WNV in the state (onset of aseptic meningitis Aug 10, ann Sept 6). Ongoing surveillance throughout California since 2000 had not detected WNV in mosquitoes, birds, or other animals--the typical "early warnings" that have preceded detection of human cases in other places. Since the woman had not recently travelled out-of-state, her case was the first evidence of WNV in California [Full text news release accessed from http://www.westnile.ca.gov/]. Another two people in the Los Angeles area were subsequently also confirmed WNV-positive, but were known to have acquired the virus out-of-state (according to a LA Times reporter Sept 10).
[CA WNV Surveillance http://westnile.ca.gov] - Canada: (Updated with information from Mar 6 2003) In 2002 WNV was detected in 5 provinces (Manitoba, Nova Scotia, Ontario, Quebec, Saskatchewan), as well as in an "imported" human case in Alberta that was likely acquired while travelling in the US.
The Toronto Globe & Mail reported on Feb 28 2003 that doctors with the Canadian Infectious Disease Society (CIDS) suspect that case counts were much higher in 2002 than officially reported. They suspect about 1000 symptomatic cases (at least 11 fatalities) in 2002, according to studies done at Toronto-area hospitals. This compares with Health Canada reports of 343 cases as of Feb 26 2003, up from the Oct 29 2002 Health Canada report of 110 human cases (31 confirmed: 1 fatality in Sept 02; 79 suspected: 5 fatalities). [Toronto Star Feb 19 2003] [Toronto Globe and Mail Feb 28 2003].
Most of the human cases were in Ontario, but 1 suspected and 3 confirmed cases were residents of Quebec. One case in Ontario was also likely acquired while travelling in the US. A 47-year-old woman who received many blood transfusions during the summer for treatment of cancer died Nov 21, in Toronto. She was confirmed a week later to be have been infected with WNV. If suspicions were confirmed that her infection was contracted from a blood transfusion, hers would be the first such case in Canada. The first WNV-positive crow in 2002 was found on May 19, just west of Toronto, Ontario, nearly 3 months earlier than the first detection of WNV-positive birds in 2001 (crow found Aug 8 in Windsor, Ontario). WNV surveillance for the 2002 mosquito season began May 15 in all provinces.
First Sero-prevalence Study of WNV to Begin in Canada (Mar 6 2003): Researchers from McMaster University conducted the first sero-prevalence study of WNV in Canada among residents of South Oakville, which had the highest rate of infection in North America with 58 cases since August 2002 [Mar 6 TORSTAR].Alberta: Though a human case was reported Oct 22 2002 in a resident of southern Alberta, it was likely that the individual became infected while traveling in the high incidence areas of Louisiana and Texas that summer.
The first confirmation of WNV in Canada was Aug 23, 2001 in a young-of-year male crow found August 8 in Windsor, Ontario (a city right across the river from Detroit, in the southernmost part of Canada). By end of 2001, 128 birds were confirmed WNV-positive (76 bird cases were identified prior to Sept 25; 25, Sept 25 - Oct 9; 21, Oct 9 - Nov 8; and none after Nov 9). Distribution of WNV-positive birds was centered in the Toronto and Windsor Ontario areas and the Regions between them, [More].
Manitoba: The first time WNV was detected in the Province or west of Ontario was a crow found in Winnipeg (S Manitoba) July 7 2002. As of Feb 6 2003, 15 mosquito pools, 236 horses and 88 crows tested WNV-positive in 2002 in the lower 87 Municipalities. WNV was also found in sentinel chickens (7), squirrels, a domestic geese flock, a wild Canada goose, a duck, and a snowy owl in the Province. Aedes vexans was the mosquito species most often found to be WNV-positive in this area, but Culex tarsalis was also found in a number of mosquito pools.
To report a bird in Winnipeg call 788-8200, or anywhere else in Manitoba, call 1-888-315-9257.
The bird surveillance program for the summer ended on Sept 27 2002, though horse and human surveillance continued.
Nova Scotia: The first case of WNV in Nova Scotia was confirmed Sept 20 2002, in a blue jay found in Dartmouth. A crow in Kingston (found Aug 26) and a blue jay in Brookfield (near Truro) were also confirmed WNV-positive (ann Sept 30). These locations are NE of Maine, the furthest east that WNV has been detected in North America, at approximately the 65th meridian.
Ontario: The first WNV-positive crow in 2002 was found just west of Toronto on May 19, nearly 3 months earlier than the first detection in 2001, in a crow found Aug 8 2001 in Windsor [More]. WNV was found in 37 regions of Ontario in 2002. Human cases were primarily in the Greater Toronto area. Median age for the first 148 confirmed cases was 56 (range 28-86). Some doctors suspect that human case numbers are far higher than officially reported (see Canada summary above). As of Feb 6 2003, 240 mosquito pools in 19 regions, 281 birds in 37 regions, and 101 confirmed and 6 probable equine cases tested WNV-positive in 2002 [More].
Quebec: (Oct 29) WNV-infected mosquitoes were found for the first time in Quebec in the region around Oka, west of Montreal, on Aug 16 2002, the first detection of WNV east of Ontario. One suspected and 3 confirmed human cases were residents of Quebec. To report a dead bird or for more information in Quebec call 1-800-463-2191.
Saskatchewan: A dead magpie in Regina was the first confirmed WNV case in this Province and the westernmost detection in Canada (near to the 105th meridian) (ann Aug 19). At the time of this announcement, the finding was nearly due north of the westernmost detections in the US, in eastern Wyoming and central Colorado. Six equine cases were ann Sept 6.
[Saskatchewan Agriculture, Food and Rural Revitalization: http://www.agr.gov.sk.ca/]
Dr Harvey Artsob, chief of zoonotic diseases at Health Canada, Winnipeg, had examined a crow from the area in 2000 that tested WNV-positive on a first test, but because of its decayed condition could not be confirmed on follow up tests. In 1999, a 75-year-old man from Toronto died after being infected while visiting NY.
[Population and Public Health Branch of Health Canada: http://www.hc-sc.gc.ca/pphb-dgspsp/wnv-vwn/index.html
Canadian Cooperative Wildlife Health Centre: http://wildlife.usask.ca/WestNileAlertHTML/WestNileAlertEng1.htm
Ontario Public Health-West Nile Virus: http://www.gov.on.ca/health/english/program/pubhealth/wnv_mn.html] - Caribbean: (Updated Oct 7 2002) A WNV Surveillance workshop was held on Apr 29-May 3, 2002 at CAREC, Trinidad and Tobago.
On Oct 17, 2001, US CDC confirmed that a 32-year old man who lives on the small island of Cayman Brac in the Cayman Islands (due south of Miami, south of Cuba and NW of Jamaica) was hospitalized in late Aug 2001 with WNV. He had not traveled outside the Cayman Islands during the previous 6 months and hence, this was the first case of WNV in the Cayman Islands and the greater Caribbean Region [More]. This case was not surprising since several WNV cases were contracted earlier in 2001 in or near the Florida Keys, at the southern tip of the state, and only a hop, skip and jump away from the Caribbean Islands. Health officials said that subsequently they "would test any dead birds that are found." Alan Wheeler, the Senior Research Officer at the Cayman Islands Mosquito Research & Control Unit, reported in an email to ERAP (Oct 2002): "I have been testing local bird and mosquito populations for WNV since our first human case of the disease in August 2001. So far I have not found the virus in any birds or mosquitoes." [More on WNV Disease Pontential in Central and S. America]
[Caribbean Epidemiology Centre: http://www.carec.org] - Colorado (Updated Dec 19 2002) There were 12 human cases in 2002. The first was a 42-year-old man from Commerce City, Adams Co onset Sept 3 (ann Sept 18 2002). In 2002, WNV was detected in 33 counties in 378 horses of 751 tested, 131 birds, 15 mosquito pools of 362 tested and 3 sentinal chickens of 1342 samples tested. WNV was detected for the first time in Colorado on Aug 19 2002 in 3 counties: Weld (western Great Plains, near to the 105th meridian), Logan (northern border with Wyoming and Nebraska) and Pueblo (on the Arkansas River in the SE).
In 2001, 32 dead crows were tested for WNV and all results were WNV-negative.
[CO WNV Surveillance http://www.cdphe.state.co.us/dc/zoonosis/zoonosis.asp] - Connecticut: (Updated Dec 19 2002) In 2002 WNV was detected in all 8 counties and confirmed in 17 humans, the first of which was a 70-year-old man from Old Greenwich (presumed onset mid-Aug; hospitalized Aug 26; ann Aug 30). In 2002, 4 horses, 528 wild birds and 305 mosquitoes of 167,008 tested (Culex pipiens, Culex restuans, Ochlerotatus trivittatus) were confirmed WNV-positive. There were also 3772 dead crows and 7173 other dead birds sighted throughout the state. The first bird for 2002 was found Apr 30 in NE Rocky Hill (Hartford Co). Surveillance, coordinated by the Dept of Public Health (DPH), began May 6 2002 for WNV-infected birds, and surveillance of birds, humans, domestic animals and mosquitoes ended in Nov 2002.
In 2001, WNV was detected in at least 7 of the 8 counties in CT. Six people were hospitalized with WNV, one of whom died (a woman in her nineties from New Haven (onset of symptoms in late Sept, died mid Oct, ann Oct 31) Reported at: http://www.dep.state.ct.us/mosquito/press/2001/as1031a.htm. The first human cases of 2001 were announced Sept 7: 2 persons in their sixties (exposed early Aug, disease onset mid-Aug, hospitalized several days later and subsequently discharged). One was a tourist who had been vacationing in both Staten Island, NY and Norfolk, CT and thus may have contracted WNV in either place. The third case was a 70+ year old resident of West Haven who was likely exposed during the latter half of Aug, became ill at the end of Aug and as of early Sept still remained hospitalized in critical condition. Two additional cases were announced Sept 27: a Bridgeport resident in the 30s and a North Haven resident over 75 years. Both became ill the first week of Sept. In 2001 USDA APHIS reported 11 WNV-positive horses in 5 counties (4 fatalities) and the first of which was announced Aug 29 2001. As of Nov 7 2001, 442 of 1061 birds tested WNV-positive including at least 13 species (crows, blue jays, a robin, a verio, a sparrow, a catbird, a great horned owl, a mourning dove, a rock dove); of that total 431 were Corvids (American or fish crow, or blue jay). As of Sept 12 2001, WNV was detected in 12 of the nearly 100 mosquito pools tested (first findings ann July 19 2001).
In 2000 WNV was detected in one person with mild symptoms and in 7 horses, of which 4 recovered and 3 were euthanatized. [The Connecticut Mosquito Management Program: http://www.mosquito.state.ct.us. ] - Delaware: (Website checked Dec 19 2002) In 2002, DE confirmed its first human case of WNV in a 39-year-old man from Kent Co (ann Oct 22 2002) [More]. As of Oct 25 2002, a total of 14 wild birds were confirmed WNV-positive from northern New Castle Co (13; northern DE) and Kent Co (1; southern DE). The first detection in 2002 was a crow found July 9 in NE DE [More]. According to APHIS, there were 13 equine cases in 2002.
In 2001, DHSS reported 17 WNV-positive birds (mostly crows, some blue jays). The first cases for 2001 were two dead crows out of 175 birds testes, (N DE, found Aug 16 and 17, ann Aug 30 2001). A first equine case in DE and the first occurrence of WNV in Sussex Co (near Georgetown) was a horse that died Oct 10 2001 [More]. The first WNV-positive mosquito pool (Culex) was collected in Wilmington Sept 14 2001 (ann Oct 4 2001). Previously, a mosquito pool announced June 29 as WNV-positive, retested negative (ann July 9 2001).
[Delaware Health and Social Services Public Information Page: http://www.state.de.us/dhss/main/info.htm
Delaware DNREC: http://www.dnrec.state.de.us/dnrec2000/#]
ERAP's West Nile Virus education program has been supported by Smith-Lever funds from the USDA Cooperative State Research, Education and Extension Service (CSREES), through a grant from Cornell Cooperative Extension, and by a grant from the National Oceanic & Atmospheric Administration's Office of Global Programs (NOAA-OGP) for the project "Climate Effects, West Nile Virus Vector Development, and Transmission Risk" (Sept 1, 2004-Aug 31, 2007).
