West Nile Virus Update -
Spreading Farther And Wider
From Dr Patricia Doyle
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases

Now that the West Nile virus (WNV) surveillance data reported to CDC through ArboNET are appearing weekly in MMWR (see part 7 below), ProMED-mail will no longer provide abstracted information from the USGS West Nile virus maps. A summary map of the current situation is reproduced in MMWR, and the more detailed USGS maps, down to county level in some categories, can be accessed via < for anyone requiring such detailed information.
Now that the 2003 West Nile virus season is in full swing, only extensions of West Nile virus geographic range or host species, and exceptional items, will be posted separately from these weekly updates. - Mod.CP
In this update:
[1] Alligators, role as amplifying hosts
[2] Equines (Tennessee)
[3] First human case (Pennsylvania, Bucks County)
[4] First human case (Kansas)
[5] Second human case (New Mexico)
[6] First human case, suspected (Kentucky)
[7] Four confirmed, plus 17 suspected human cases (Nebraska)
[8] First human case (Arkansas)
[9] First human case (North Carolina)
[10] Human cases (Wyoming)
[11] CDC-ArboNET West Nile virus update (31 Jul to 6 Aug 2003)
Date: Sun 3 Aug 2003
From: Dale E Reddick <
Source: Palm Beach Post, Associated Press report, Sun 3 Aug 2003 [edited]
Potential Role of Alligators in West Nile Virus Transmission
Alligators might be as effective as birds at transmitting West Nile virus, University of Florida scientists have reported.
The virus is spread by mosquitoes, which transmit it from infected birds. But researchers found levels of the virus in alligators that are as high as in birds, which means that the reptiles can likely pass on the infection to other animals, said Elliot Jacobson, an expert in reptile disease at the university. "They have levels overlapping with that of some birds, and a certain level needs to be reached in order to infect mosquitoes," Jacobson said. "Horses and humans do not have these levels."
The findings come from a study of about 300 captive alligators that died in 2002 in Christmas [Florida]. Necropsies showed that the alligators had viral loads of West Nile virus that were high enough to infect mosquitoes. The alligators were probably infected initially by mosquitoes, which bite the alligators' soft eyelids, tongues, and mouths, Jacobson said. Then the alligators spread the virus among themselves through water in their holding tanks. Although birds often die within hours of contracting the virus, alligators may live for days or weeks after being infected, Jacobson said. That would allow the alligator to pass the virus on to more mosquitoes.
But overall, Jacobson said alligators probably play a small role in transmitting the virus to mosquitoes and people because there haven't been more human cases in areas with alligators.
Dale E Reddick
Date: Sun 3 Aug 2003
From: ProMED-mail <
Source:, Sun 3 Aug 2003 [edited]
Tennessee: First Equine Deaths Due to West Nile Virus Infection
2 horses in East Tennessee have died as the result of the West Nile virus infection. The deaths in Blount County and Hamilton County are the first confirmed in 2003 among Tennessee's horse population. No human cases have been reported in Tennessee, although 55 people developed the disease in 2002 and 7 died from it.
Date: Sun 3 Aug 2003
From: ProMED-mail <
Source: The Morning Call, Thu 31 Jul 2003 [edited]
Pennsylvania: First Human Case of West Nile Virus Infection in Bucks County
West Nile virus hit Bucks County without warning on Wed 30 Jul 2003, afflicting a 39-year-old man who has been hospitalized with symptoms that suggest the disease had progressed beyond its early flu-like stage. The victim is the first person from Bucks County to contract the disease since the virus started showing up on the East Coast in 1999, said Dr. Lewis D. Polk, medical director of the Bucks County Health Department. In previous years, he said, birds and horses in Bucks County have tested positive for the disease, and mosquito pools were found to contain West Nile-carrying insects. So far in 2003, Polk said, the county Health Department has tested several dead birds and larva samples taken from mosquito nests, but no positive tests had been reported. Last year, 62 Pennsylvanians tested positive for West Nile virus. There were 9 fatalities.
The Bucks County man was one of 7 victims of West Nile virus infection announced on Wednesday by the state Health Department. Until then, there had been only a single positive human case in Pennsylvania in 2003; a woman from Philadelphia. State health officials said the other victims included a 44-year-old woman from Lancaster County, a 53-year-old man from York County, a 46-year-old man from Allegheny County, a 75-year-old man from Lawrence County, a 43-year-old woman from Lebanon County, and a 53-year-old man from Cameron County.
[Byline: Hal Marcovitz]
Date: Sun 3 Aug 2003
From: ProMED-mail <
Source: Lawrence Journal-World, Sat 2 Aug 2003 [edited]
Kansas: First Human Case of West Nile Virus Infection in 2003
Kansas health officials have confirmed the first human case of West Nile virus in the state for 2003. A 38-year-old Gray County resident first reported signs of meningitis on 20 Jul 2003 and is now recovering, said Sharon Watson of the Kansas Department of Health and Environment. West Nile virus can cause meningitis in humans.
In its second year in Kansas, the virus has been confirmed by the department in 25 counties. All other cases have been in birds, horses or mosquito pools. Gray County is in southwest Kansas. Last year, 103 of 105 Kansas counties reported cases in either humans, horses, birds, or mosquitoes. There were 22 human cases but no deaths.
Kim Ens, disease control program coordinator for the Douglas County Health Department, said more cases of the disease typically were found in the second year of an outbreak. But she said drought this year might have kept West Nile from spreading as quickly, because mosquitoes, which transmit the virus, don't have as much standing water in which to lay eggs. But Watson said the state had anticipated more cases beginning earlier this year based on studies of the virus in states on the East Coast. So far, she said, the virus does seem to have appeared at an accelerated rate. The first case this year was confirmed 28 May 2003, whereas 2002's first case was in late July.
[Byline: Caroline Boyer]
Date: Wed 6 Aug 2003
From: Ami Logan <
Source: KOAT Action 7 News, Wed 6 Aug 2003 [edited]
New Mexico: 2nd Human Case of West Nile Virus Infection
There has been another confirmed human case of West Nile virus in New Mexico. The first case this year was reported last week in Valencia County. The patient in the second case is from Colfax County in northern New Mexico and involved a 42-year-old woman who reported the sudden onset of flu-like symptoms. Her doctor was alert to the possibility of West Nile and had the disease confirmed by lab tests. State health officials said the virus was more advanced in the Valencia County case. They said West Nile only shows symptoms in 20 percent of the people who contract it. The serious cases progress to encephalitis, and that's what the Valencia County woman had. The experts said that in only one in 150 cases does West Nile get that far. The woman recovered and has since been released from the hospital.
Ami Logan
Date: Wed 6 Aug 2003
From: ProMED-mail <
Source: The Cincinnati Enquirer, Wed 6 Aug 2003 [edited]
Kentucky: First Case of Suspected West Nile Virus Infection
A Boone County resident is believed to be the first person from the Tristate, as well as the first Kentuckian, to be stricken with West Nile virus this year. The person, who developed symptoms of the mosquito-borne illness within the past 2 weeks, is listed as a "probable" case by the Kentucky Cabinet for Health Services. That means state laboratory tests for the virus were positive but must be confirmed through additional testing by the federal Centers for Disease Control and Prevention, said Dr. Sue Billings, an epidemiologist with the Kentucky Health Services Department. Billings said the person sought treatment after showing symptoms of the virus about 2 weeks ago. Those can include fever, headache, muscle aches, and chills. The Boone County "case was not hospitalized and is doing well," Peggy Patterson, a spokeswoman for the Northern Kentucky Independent District Health Department, said Tuesday.
Horses or birds with West Nile virus have been reported in 9 Kentucky counties in 2003, including Kenton County. On Monday, Northern Kentucky health officials confirmed that mosquitoes trapped in a Boone County pool recently tested positive for the West Nile virus.
[Byline: Cindy Schroeder]
Date: Wed 6 Aug 2003
From: ProMED-mail <
Source: Lincoln Journal Star, Associated Press report, Wed 6 Aug 2003
Nebraska: 4 Human Cases of West Nile Virus Confirmed; 17 Cases and 31 Blood Donations Pending
4 human cases of West Nile virus infection have been confirmed in Nebraska, and 17 other probable cases are awaiting confirmation. The Centers for Disease Control and Prevention confirmed cases in 2 Buffalo County men, ages 60 and 76; a 45-year-old Gage County woman; and a 19-year-old Lancaster County woman, state health officials said Tue 5 Aug 2003.
State health officials last month reported its first presumed human case of West Nile in a Nebraska City woman in Otoe County. Dr. Richard Raymond, the state's chief medical officer, said initial test results at the state health lab for West Nile Virus in that case were not confirmed by the CDC.
In addition, the American Red Cross reports 31 positive blood donors, giving Nebraska the highest number of positive blood donors in the country, health officials said. None of those tests has been confirmed but may be tested further if the donor develops symptoms of West Nile virus.
There have also been 50 positive birds and 242 positive pools of mosquitoes found in the state. The Department of Agriculture reports 14 positive horse cases.
[see: Nebraska Department of Health and Human Services website:]
Date: Thu 7 Aug 2003
From: ProMED-mail <
Source: The Log Cabin Democrat of Conway, Arkansas, Associated Press
report, Thus 7 Aug 2003 [edited]
Arkansas: First Human West Nile Virus Case of 2003
Arkansas has its first human case of West Nile virus this year, state health officials said on Wed 6 Aug 2003.The case, in Jefferson County, was confirmed by the state Health Department's laboratory. Ann Wright, a spokeswoman for the department, said a suspected human case of the disease was reported in July 2003 in Washington County, but state tests came back inconclusive. She said the tests were being reviewed by the Centers for Disease Control and Prevention in Atlanta.
During 2002, the state had 43 confirmed human cases, resulting in 5 deaths.
Also on Wednesday, the department said that birds in Cleburne, Mississippi, and Sebastian counties tested positive for West Nile virus. Earlier in 2003, birds tested positive for the virus in Arkansas, Benton, Clark, Crawford, Hot Spring, Jefferson, Little River, and Union counties. Horses also have tested positive in Logan and Sebastian counties, and a positive mosquito pool was reported in Greene County.
Date: Thu 7 Aug 2003
From: ProMED-mail <
Source: The Herald, Wed 6 Aug 2003 [edited]
North Carolina: Human Case of West Nile Virus Infection Confirmed
A man in an unnamed eastern North Carolina community is the first in the state to be infected with the West Nile virus this year, health officials said on Wed 6 Aug 2003. The victim is recovering from the virus at home, was not hospitalized and never displayed neurological problems, which can include inflammation of the brain or the lining of the brain and spinal cord, health officials said.
The virus has been found in 2003 in birds from 24 counties from Dare County on the coast to Macon County in the west. Wild birds carry the virus. Mosquitoes bite the birds and then can transmit the virus to humans.
The North Carolina man was probably among the 20 percent of human cases who develop a mild illness with fever, headaches, body aches, an occasional skin rash, and swollen lymph nodes, state officials said. A blood sample sent to the state public health laboratory confirmed the man's exposure to the virus.
Date: 7 Aug 2003
From: ProMED-mail <
Source: Casper Star-Tribune, Associated Press report, Wed 6 Aug 2003
Wyoming: Second Human Case of West Nile Infection Reported
A Laramie County woman has become the second person in Wyoming to come down with West Nile virus infection in 2003. The woman had only light symptoms and was recovering, Cheyenne-Laramie County Health Department Director Gus Lopez said Wed 6 Aug 2003.
Health officials said the risk for more West Nile cases in Laramie County is high due to heavy spring precipitation and current hot weather. 8 cases of the virus in birds and 2 in horses have been confirmed in Laramie County this year.
On Fri Aug 2003, a Torrington woman was diagnosed with Wyoming's first West Nile case of the year. The diagnosis came a month earlier in the year than last year's diagnosis of 2 Wyomingites, the only 2 cases of 2002.
Health officials in Wyoming said they have been on heightened alert for West Nile since the recent death of a 77-year-old Greeley, Colo., woman. The woman was hospitalized after experiencing headaches, dizziness, and nausea.
The number of West Nile cases typically peaks in early September. During 2002, the malady was found in 96 horses, 20 birds, and 2 humans in Wyoming. The 2 human cases were not fatal.
Date: Thu 7 Aug 2003
From: ProMED-mail
Source: Morbidity and Mortality Weekly Report, Fri 8 Aug 2003 / 52(31);741
United States: West Nile Virus Activity; Thu 31 Jul to Wed 6 Aug 2003
----------------------------------------------------------------------</ FONT>
This report summarizes West Nile virus (WNV) surveillance data reported to CDC through ArboNET as of 3 a.m., Mountain Daylight Time, Wed 6 Aug 2003.
During the reporting week of 31 Jul to 6 Aug 2003, a total of 109 human cases of WNV infection were reported from 13 states (Colorado, Iowa, Kansas, Kentucky, Louisiana, Minnesota, Mississippi, Nebraska, New Mexico, North Dakota, Ohio, South Dakota, and Texas), including 4 fatal cases from 3 states (Alabama, Colorado, and Texas). During the same period, WNV infections were reported in 622 dead birds, 191 horses, one dog, 4 unidentified animal species, and 359 mosquito pools.
During 2003, a total of 153 human cases of WNV infection have been reported from Colorado (n = 72), Texas (n = 19), Louisiana (n = 15), South Dakota (n = 8), Ohio (n = 7), Alabama (n = 6), Nebraska (n= 6), Florida (n = 4), Minnesota (n = 4), Mississippi (n = 4), Iowa (n = 2), New Mexico (n = 2),
Kansas (n = one), Kentucky (n = one), North Dakota (n = one), and South Carolina (n = one). Among 150 (98 percent) cases for which demographic data were available, 81 (54 percent) occurred among men; the median age was 45 years (range: 17 months to 87 years). Of the 153 cases, 4 fatal cases were reported from Alabama (n = one), Colorado (n = one), and Texas (n = 2). In addition, 1770 dead birds with WNV infection were reported from 36 states and New York City; 282 WNV infections in horses have been reported from 22 states (Alabama, Arkansas, Colorado, Florida, Georgia, Kansas, Kentucky, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Mexico, North Carolina, North Dakota, Oklahoma, South Dakota, Tennessee, Texas, Virginia, Wisconsin, and Wyoming), 3 WNV infections were reported in dogs, and 5 infections were reported in unidentified animal species.
During 2003, WNV seroconversions have been reported in 185 sentinel chicken flocks from 8 states (Colorado, Florida, Georgia, Iowa, Louisiana, Nebraska, North Carolina, and Virginia). Louisiana and South Dekota each reported 3 seropositive sentinel horses. A total of 1038 WNV-positive mosquito pools have been reported from 20 states (Colorado, Connecticut, Georgia, Illinois, Indiana, Kansas, Louisiana, Maryland, Massachusetts, Michigan, Mississippi, Missouri, Nebraska, New Jersey, North Dakota, South Dakota, Tennessee, Texas, Virginia, and Wisconsin) and New York City.
Additional information about WNV activity is available from CDC at and
[The cases in Arkansas, North Carolina, Wyoming, and the unconfirmed cases in Pennsylvania and Nebraska described above, are in addition to the data included in the CDC-ArboNET report for the period 31 Jul to Wed 6 Aug 2003.
Please note that ProMED-mail will no longer post data on individual cases except where that case may be the first in an area. We thank the many correspondents who have contributed to the surveillance effort by reporting from their own areas. It has become clear from the evidence of early detection of West Nile virus infection in blood donations from healthy donors that the reporting of symptomatic cases of West Nile virus infection may give a subaccurate indication of the prevalence of the virus in the human population. - Mod.CP]
ProMED-mail makes every effort to verify the reports that are posted, but the accuracy and completeness of the information, and of any statements or opinions based thereon, are not guaranteed. The reader assumes all risks in using information posted or archived by ProMED-mail. ISID and its associated service providers shall not be held responsible for errors or omissions or held liable for any damages incurred as a result of use or reliance upon posted or archived material.
Visit ProMED-mail's web site at < Send all items for posting to: (NOT to an individual moderator). If you do not give your full name and affiliation, it may not be posted.
Send commands to subscribe/unsubscribe, get archives, help, etc. to: For assistance from a human being send mail to:



This Site Served by TheHostPros