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West Nile Virus

Started by RNOfficer, July 18, 2016, 11:52:01 PM

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RNOfficer

While Zika virus is getting all the publicity, it's worth emphasizing the much greater present danger of West Nile Virus.

For example, the CDC reports 544 Neuroinvasive Disease Cases from West Nile in California alone.

Neuroinvasive diseases include aseptic meningitis, encephalitis, or acute flaccid paralysis (AFP)..

Preventive measures:

http://www.mayoclinic.org/diseases-conditions/west-nile-virus/manage/ptc-20166334

Because birds (particularly crows) are the primary host (humans and horses are incidental hosts) ALWAYS report any increase in dead birds to your local heath department ( usually a County function).

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Thanks, RNOfficer.

This is a useful reminder/reference.

V/R,
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LSThiker

#2
Quote from: RNOfficer on July 18, 2016, 11:52:01 PM
While Zika virus is getting all the publicity, it's worth emphasizing the much greater present danger of West Nile Virus.

For example, the CDC reports 544 Neuroinvasive Disease Cases from West Nile in California alone.

Neuroinvasive diseases include aseptic meningitis, encephalitis, or acute flaccid paralysis (AFP)..



In 2015, California had 544 neuroinvasive (NI) West Nile Virus (WNV) cases with 186 non-NI.  Of the 730 cases, only 45 died.  So that should be the CDC reported and not reports as in the present. 

Currently, the state of California is reporting no cases of WNV as of 7/18/2016.  However, there are 547 dead birds, 896 mosquito pools, and 19 sentinel chickens infected with WNV according to the California Dept of Public Health.  There are 30 counties currently that have WNV activity:  23 with dead birds, 26 with mosquito samples, and 4 with chickens.

The last set of data published from the CDC puts last year (2015) at 1,360 NI cases, 700 non-NI cases, and 119 deaths.  Taking this information, we can back calculate the theoretical total number of cases.  Long-story short, on average ~80% of people will never show any symptoms, while ~19-20% will show a viral-like symptoms (fever, aches, headache, vomiting, [like nearly all initial symptoms of a flu or virus infection]).  <1% will actually develop a neurological illness, of which about 10% will die (or <0.1% of total cases).

My point is this:

While WNV is something to be concerned about scientifically, practically for the lay-person it is rather unimportant except as a nice scare tactic.  There is not a "greater present danger" from it really. 

Especially when there are other vector-borne pathogens that cause more problems.  For example, last year over 3,000 cases of rickettsioses (RMSF, Endemic typhus, Ehrlichia, Anaplasma, etc) were reported last year to the CDC.  Even though doxycycline is an effective treatment, some of these diseases still have a mortality of 1-4%.

Dengue Fever has had outbreaks in Hawaii and Puerto Rico.  There have been flare ups in the Florida keys between 2009 and 2011 and Brownsville, TX in 2005.  The vast majority of people are asymptomatic while only 15% of patients develop serious complications.  Less than 1% will die from DF.  When Dengue Hemorragic Fever (DHF) is diagnosed, 2-5% with treatment and nearly 50% without.

In Puerto Rico and US Virgin Islands you also have to worry about Chikungunya.  The southern border states also need to worry that Chik is going to go North from Mexico as predicted by experts in the Center for Biodefense and Emerging Infectious Diseases at UTMB. 

Lyme disease had a confirmed 25,359 cases last year according to the CDC.  Although, estimates really put the case rate well over 300,000. 

Bottom line, just wear bug spray.  Anything else just scares people.