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8-26-02
A fifth case of BSE has been found in Japan (6y.o. cow). Although the report, below, says confirmatory tests are in progress, those tests have been completed and confirmation was provided. The effect on Japan's economy has been dramatic. Details on this 5th case haven't been reported yet, but in a follow-up report (below) this 5th case appears to be tied to the same milk replacer that linked the other 4 cases.
On WNV general update. We now have cases here in Montana. Little quicker than many of us expected, though the virus is in the eastern part of the state where mosquito populations are still thriving. The Montana cases are 3 confirmed horses (1 dead) and at least 5 other suspects. New Mexico now has equine cases of WNV, 2 horses in Quay and Curry Counties (the far east side of the state). In an interesting epicenter in Indiana, a local veterinarian reports that about 200 of Daviess County estimated horse population of 4500 are showing signs of the disease. Official numbers are considerably less, but if true, that would suggest a clinical attack rate of about 4.5%, much higher than previously reported. Vaccine is being used in that state, but there are no numbers to compare clinical attack rate in the vaccinated vs non-vaccination population. Thus far about 25 horses have died or were euthanatized for a case fatality rate of 12.5% (which, of course, could go do has something like 7 equine cases. The latest figures mean WNV has been confirmed in all but 7 of the 48 contiguous states. In Canada, cases have cropped up in Regina Saskatchewan and to the northwest.
I contacted Ft. Dodge last week to get information on the effectiveness of the WNV equine vaccine. Originally the vaccine was provisionally licensed with an expiration of August 1, 2002. Unfortunately, Ft. Dodge did not get efficacy data to USDA soon enough for evaluation for full licensure this year. The provisional license has been renewed until August 2003. Ft. Dodge refused to share data on efficacy saying that USDA had to review those first. However, one veterinarian did say field data looked "quite good". In another conversation I was able to learn that the company conducted actual
challenge studies on the vaccine in addition to what they learned from the field. Although data could not be released, when pressed he stated that the data "will be supportive of full licensure". Translated - there was at least some, maybe much, protection. So far over 1.6 million doses have been delivered, with a far less than 1% reported (keep in mind, "reported") adverse effect.
According to the CDC, as of 23 August 2002, a total of 371 human cases of WNV with 16 mortalities have been reported in 2002. Even allowing for some error in numbers, if you think about the population of the US the totals again reinforce that WNV has a very low clinical attack rate and very low mortality rate.
Thomas J. Roffe, PhD, DVM
Northern Rocky Mountain Science Center
USGS-BRD
FWP Bldg, 1400 S. 19th Ave.
Bozeman, MT
T: 406-994-5789
F: 406-994-4090
Cell: 406-539-4955
Supporting Documents:
Date: Thu, 22 Aug 2002
From: ProMED-mail <promed@promedmail.org>
Source: AP Online 22 Aug 2002 [edited]
More Mad Cow [Disease] Suspected in JapanJapan discovered a fifth suspected case of mad cow disease Thu, 22 Aug 2002, reviving fears that the government has failed to stem the disease since an outbreak late last year.
Despite government assurances that homegrown beef is safe to eat, the news that another cow may be infected comes just 3 months after Japan confirmed its fourth case of the deadly, brain-wasting illness. The 6-year, 8-month-old Holstein dairy cow tested positive for the disease during a regular inspection by health officials in Atsugi city, west of Tokyo, local government spokesman Hideya Inomata said.
Samples of the cow's brain and spinal cord were sent to a government research center, which will run more precise tests to finally determine whether the cow is infected. The rest of the animal's carcass was being held in cold storage until the tests come back, as early as Fri 22 Aug 2002, he said.
Since Tokyo began regular screening of all cattle bound for human consumption last October [2001], 95 cows have turned up positive in reliminary tests, Inomata said. But only 3 of those tests were confirmed in follow-up examinations. Still, the possibility of another infected animal among the 4.56 million cows nationwide generated immediate concern. In September 2001, Japan became the first country to find a diseased cow outside of Europe, where the disease has devastated cattle farmers. Two other cows tested positive in Nov 2001, and a fourth case was confirmed May 2002.
Tokyo has tried to reassure a jittery public that the country's beef stocks are free of the tainted meat. On Thursday, the Agriculture Ministry was considering continuing testing cows through the next fiscal year, beginning in Apr 2003. More than 1 million cows nationwide have already been tested. So far the tests have failed to assuage concerns, with surveys after the outbreak late last year suggesting that as many as one in 4 Japanese had stopped eating beef. Japan has banned the use of meat-and-bone meal as cattle feed, in addition to its extensive screening of slaughtered cattle.
Date: 24 Aug 2002
From: ProMED-mail <promed@promedmail.org>
Source: Kyodo News, Japan Today 24 Aug 2002 10:00 JST <http://www.japantoday.com/e/?content=news&cat=1&id=227614>5 cows with mad cow disease fed milk substitute
Kanagawa prefectural government officials said Friday a Holstein dairy cow confirmed to be Japan's fifth case of mad cow disease was probably fed a milk substitute which is similar to those given to 4 other cows earlier confirmed with the disease.
The officials said the milk substitute -- given to calves until they are weaned -- was produced by the same maker which supplied the milk products fed to the first 4 infected cows.
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URL: http://biology.usgs.gov/cro/WNV8-26-02.htm
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