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	va1-sg19016.securesites.net

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Human cases were reported for week 38 (as of 22 Sep 2007) from the 

Province / Neurological / Non-Neurological / Unclassified-Unspecified 

/ Total* / Asymptomatic**



Ontario / 1 / 9 / 0 / 10 / 3

Manitoba / 55 / 343 / 145 / 543 / 8

Saskatchewan / 40 / 423 / 844 / 1307 / 14

Alberta / 18 / 271 / 0 / 289 / 2

British Columbia / 6 / 5 / 5 / 16*** / 0

TOTALS / 120 / 1051 / 994 / 2165 / 27



* Neurological syndrome (plus) Non-Neurological syndrome (plus) 

Unclassified-Unspecified (equals) Total

** Most identified through blood donor testing; not included in total cases

*** Infection acquired while traveling outside the province



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Of the 7 provinces testing dead wild birds for West Nile virus as of 



Province / American crows / Blue Jays / Black.-billed Magpies / 

Common Ravens / Other



Atlantic Region* / 0 of 344** / 0 of 27 / 0 of 0 / 0 of 35 / 0 of 1

Ontario / 71 of 497 / 6 of 186 / 0 of 0 / 0 of 50 / 0 of 0

Western Region *** / 40 of 731 / 0 of 4 / 5 of 22 / 0 of 17 / 15 of 24



* New Brunswick, Nova Scotia, Prince Edward Island

** Positive of total tested

*** Manitoba, Saskatchewan, Alberta, British Columbia



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******

of Vector-Borne Infectious Diseases, West Nile virus [edited]





2007 West Nile virus activity in the United States (through 2 Oct 2007)

-----------------------------------------------------------------------

State / Neuroinvasion* / *West Nile* fever** / Other, Unspecified*** 

/ Total**** / Fatalities



Alabama / 12 / 1 / 0 / 13 / 3

Arizona / 10 / 4 / 17 / 31 / 0

Arkansas / 9 / 2 / 0 / 11 / 1

California / 118 / 161 / 11 / 290 / 14

Colorado / 79 / 378 / 0 / 457 / 5

Connecticut / 3 / 1 / 0 / 4 / 0

Delaware / 1 / 0 / 0 / 1 / 0

Florida / 3 / 0 / 0 / 3 / 1

Georgia / 18 / 12 / 2 / 32 / 1

Idaho / 1 / 69 / 0 / 70 / 0

Illinois / 34 / 9 / 5 / 48 / 4

Indiana / 6 / 4 / 0 / 10 / 1

Iowa / 6 / 9 / 2 / 17 / 1

Kansas / 9 / 18 / 0 / 27 / 0

Kentucky / 3 / 0 / 0 / 3 / 0

Louisiana / 1 / 1 / 0 / 2 / 0

Maryland / 3 / 3 / 1 / 7 / 0

Massachusetts / 1 / 2 / 0 / 3 / 0

Michigan / 8 / 0 / 0 / 8 / 0

Minnesota / 36 / 53 / 0 / 89 / 0

Mississippi / 34 / 51 / 0 / 85 / 3

Missouri / 37 / 8 / 0 / 45 / 1

Montana / 32 / 139 / 0 / 171 / 3

Nebraska / 9 / 72 / 0 / 81 / 3

Nevada / 2 / 4 / 4 / 10 / 0

New Mexico / 33 / 18 / 0 / 51 / 3

New York / 5 / 0 / 0 / 5 / 1

North Dakota / 44 / 280 / 0 / 324 / 2

Ohio / 6 / 3 / 1 / 10 / 0

Oklahoma / 41 / 27 / 1 / 69 / 5

Oregon / 3 / 14 / 0 / 17 / 0

Pennsylvania / 2 / 1 / 0 / 3 / 0

Rhode Island / 0 / 1 / 0 / 1 / 0

South Carolina / 2 / 2 / 0 / 4 / 0

South Dakota / 44 / 152 / 0 / 196 / 4

Tennessee / 2 / 1 / 1 / 4 / 1

Texas / 75 / 16 / 0 / 91 / 5

Utah / 17 / 20 / 0 / 37 / 1

Virginia / 2 / 1 / 0 / 3 / 0

Wisconsin / 2 / 2 / 0 / 4 / 0

Wyoming / 13 / 145 / 16 / 174 / 1

TOTALS / 766 / 1684 / 61 / 2511 / 64



* cases with neurological manifestations (such as WN encephalitis, 

meningitis*, and myelitis)

** cases with no evidence of neuroinvasion

*** cases for which insufficient clinical information was provided

**** total number of human cases of WNV illness reported to ArboNET 

by state and local health departments.

"Neuroinvasive disease" refers to severe disease cases, particularly 

West Nile meningitis and West Nile encephalitis.

"West Nile fever" refers to typically less severe cases that show no 

evidence of neuroinvasion. West Nile fever is not currently on the 

list of nationally notifiable diseases, and, therefore, it is 

optional whether or not state health departments report these cases 

to CDC. [Further explanations of neuroinvasive West Nile virus 

disease and West Nile fever can be found on the CDC website at the 

URL provided above.]

"Other" includes persons with clinical manifestations other than WN 

fever, WN encephalitis, or WN meningitis, such as acute flaccid paralysis.

"Unspecified" cases are those for which sufficient clinical 

information was not provided.

and severe human disease cases occurring since 1 Jan 2007, reported 

to ArboNET by state and local health departments. ArboNET is the 

national electronic surveillance system established by CDC to assist 

states in tracking West Nile virus and other mosquito-borne viruses. 

Information regarding 2007 virus/disease activity is posted when such 

cases are reported to CDC.



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virus [edited]





2007 West Nile virus activity in the United States (through 2 Oct 2007)

-----------------------------------------------------------------------

Data are being collected from state and local health departments on a 

weekly basis and are reported to the CDC ArboNET for the following 5 

veterinary cases, and mosquito surveillance. Maps detailing 

county-level wild birds, sentinel chicken flocks, human cases, 

veterinary cases, and mosquito surveillance data are published each 

week on the collaborative USGS (US Geological Survey)/CDC West Nile 

virus website.



As of 2 Oct 2007, human, avian, animal, or mosquito West Nile virus 

(WNV) infections have been reported to CDC ArboNET from the following 

Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, 

Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, 

Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New 

Hampshire, New Jersey, New Mexico, New York, North Dakota, Ohio, 

Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South 

Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West 

Virginia, Wisconsin, and Wyoming; Commonwealth of Puerto Rico.



WNV antibody-positive sentinel animals (birds and/or horses) have 

been found in Arizona, Arkansas, California, Delaware, Florida, Iowa, 

have WNV sentinel programs. - Mods.JW/TY]



WNV equine infections have been reported from Arizona, Arkansas, 

California, Colorado, Idaho, Illinois, Indiana, Iowa, Kansas, 

Kentucky, Louisiana, Michigan, Minnesota, Mississippi, Missouri, 

Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, 

Oregon, South Carolina, South Dakota, Tennessee, Texas, Utah, 

Virginia, Washington, and Wisconsin.



WNV has been detected in dead wild birds in Alabama, Arizona, 

Arkansas, California, Colorado, Delaware, Georgia, Idaho, Illinois, 

Indiana, Kentucky, Massachusetts, Michigan, Mississippi, Missouri, 

Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, 

North Dakota, Ohio, Oregon, Pennsylvania, South Carolina, South 

Dakota, Tennessee, Texas, Utah, Vermont, Washington, and Wisconsin.



WNV has been detected in mosquito pools collected in Arizona, 

Arkansas, California, Colorado, Connecticut, Georgia, Idaho, 

Illinois, Indiana, Iowa, Kentucky, Louisiana, Maryland, 

Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, 

Nevada, New Jersey, New Mexico, New York, North Dakota, Ohio, 

Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South 

Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, and Wyoming.



--



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Stable flies [_Stomoxys calcitrans_] are the latest suspect that may 

be involved in the West Nile virus deaths of hundreds of pelican 

chicks at the Medicine Lake National Wildlife Refuge in northeast 

Montana. West Nile virus killed 800 to 1000 pelican chicks in 2003, 

averaged 400 in each of the next 3 summers, and more than 600 this year [2007].



Veterinary entomologist Greg Johnson of Montana State University said 

earlier this year [2007] that he considered the possibility that lice 

were transmitting West Nile virus to pelicans. He became suspicious 

after collecting very few mosquitoes in 2006, but seeing pelicans 

continue to die at a high rate. Johnson discovered previously that 

the _Culex tarsalis_ mosquito is the primary carrier of West Nile 

virus in Montana and that the Medicine Lake refuge was one of the hot 

spots for the virus.



Many of the dead pelicans [_Pelicanus erythrorhynchus_] at Medicine 

Lake  had lice [_Piagetiella peralis_] crawling inside and outside of 

their beak, Johnson continued. Mike Rabenberg, deputy refuge manager, 

said external parasites -- especially pouch lice and feather lice -- 

are common on the Medicine Lake pelicans. The lice may be more 

prevalent, he said, on pelicans that are sick or weakened.



The lice were cleared, however, after Johnson sent pelican tissue 

samples and lice to the Centers for Disease Control and Prevention in 

Fort Collins, Colorado. The lab tested approximately 800 lice, but 

none was found to have West Nile even though most came from pelicans 

that tested positive.



Stable flies caught Johnson's attention when he came across a bird 

with blood on its neck and some flies feeding on the blood during the 

third week of July [2007'. Stable flies look like common houseflies, 

but they have a painful bite. They come from a different family than 

horse flies or deer flies, however.



"This (the stable fly scene) was very unusual because stable flies 

are only reported to feed on domestic livestock, humans and companion 

animals," Johnson said. "There are no reports in the literature of 

stable flies feeding on domestic or wild birds."



Johnson observed the stable flies feeding on birds several more 

times. He also collected about 1300 flies and divided them into 60 

groups. Of those groups, 18 tested positive for West Nile virus.



"This is the 1st report of stable flies feeding on wild birds, or 

pelicans for that matter, and the 1st report of stable flies infected 

with West Nile virus," Johnson said. "These results suggest that 

stable flies might be involved in amplification and/or transmission 

of West Nile virus at the pelican colony and possibly could serve as 

a vector of West Nile virus to other pelicans."



If the theory proves correct, he will have to modify some of his 

study methods because they currently focus on mosquitoes, Johnson 

said. He added that the number of captured mosquitoes was high this 

summer [2007], as well as the West Nile infection rate in those mosquitoes.



As far as the relationship among lice, pelicans, and West Nile virus 

goes, Johnson said the lice created wounds that could be a point of 

entry for the virus, however they don't pass along the virus.



"I don't think they are playing a primary role in West Nile 

transmission because they don't have to have blood for egg 

development, energy, and survival," Johnson said. "Rather, they feed 

on epidermal or skin cells which creates wounds, causing blood to 

exude and then they feed on the blood. The wounds they cause may 

provide entry sites for West Nile virus, and the young pelicans can 

get infected that way."



The Medicine Lake National Wildlife Refuge between Plentywood and 

Culbertson contains the 5th largest colony of American white pelicans 

in North America. Rabenberg said the colony normally includes 8000 to 

10 000 breeding adults and approximately 4000 nests. The adult 

pelicans fly up to 150 miles (241 km) one way a day looking for food. 

The Medicine Lake adults fly to other mosquito-rich areas like Terry, 

the Fort Peck Reservoir, and the Yellowstone River. They fly into 

Saskatchewan and North Dakota. The adult pelicans typically winter 

along the Gulf coast, but some reach southern Mexico.



--



[This interesting report adds a new biting arthropod to the list of 

suspected West Nile virus (WNV) vectors and Dr. Johnson is to be 

congratulated for making this unusual observation. However, this 

report does not prove that stable flies are vectors of the virus. 

Isolation of the virus alone is not sufficient to establish vector 

status. It is possible that stable flies are mechanical vectors -- 

transmitting the virus via virus-contaminated mouth parts. Laboratory 

experiments would be required to establish (or refute) biological 

vector status, demonstrating the virus replicates in the files 

following ingestion of viremic blood and reaches salivary glands for 

subsequent transmission to a susceptible vertebrate host.



It is also possible that the detection of WNV simply represents 

external contamination of the flies' bodies by viremic blood, and 

they do not transmit the virus at all. While it is clear that the 

stable flies had WNV in or on their bodies, the statement in the 

report above that the flies were infected with WNV is premature. One 

hopes that this report will stimulate experiments that will test for 

biological or mechanical vector capacity of this common biting fly. - Mod.TY



The location of Medicine Lake National Wildlife Refuge in the US 

state of Montana is indicated on the map at

- CopyEd.MJ]



2006

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...................................ty/mj/mpp