Griest Data Mining

How common is West Nile Virus and when is it a threat to equines?

By Allison Griest

How common is West Nile Virus and when is it a threat to equines?

Horses are used both

professionally and

recreationally.

If West Nile Virus is a threat

to horses’ existence, humans

as the horse owners have a

responsibility to protect

horses from the virus, no

matter where they live.

This presentation is catered

toward horse owners in Texas

North East Independent School District.http://www.neisd.net/elmlang/images/j0189633.jpg.Viewed 02/21/10.

History of West Nile Virus•West Nile Virus (WNV) was first diagnosed in the United States

in 1999.

•West Nile Virus is transmitted through the bite of infected

mosquitoes.

•Mosquitoes become infected

when they feed on infected

birds.

•The virus multiplies in the

horse’s blood system, crosses

the blood-brain barrier,

and infects the brain.

History of West Nile Virus•The virus has been found in all 48 of the Continental

United States.

•The virus has also been found in Africa, western Asia,

the Middle East, and the Mediterranean regions of

Europe.

Mosquito-pictures.com. http://www.mosquito-pictures.com/mosquito_pictures.htm.02/24/10.

History of West Nile Virus•According to the Center for Disease Control, the virus

interferes with the normal central nervous system

functioning and causes inflammation of the brain.

Center for Disease Control.http://www.cdc.gov/ncidod/dvbid/westnile/qa/wnv_horses.htm.02/23/10.

About West Nile Virus• WNV has an incubation period of 3 to 15 days.

•Horse-to-horse transmission of the virus is unlikely because horses

do not have significant amounts of the virus circulating in their

blood.

•Clinical signs of a WNV infection include but are not limited to:

Muscle twitching

Tremors

Difficulty rising

Convulsions

Partial paralysis

A droopy lip

Teeth grinding

Frequency of West Nile Virus•The following maps illustrate the decrease in the number of WNV

infections from 2002 to 2009.

•Notice the deep red states on the 2002 maps. States colored deep

red have 800 or more reported cases of WNV.2009 2002

United States Department of Agriculture – Animal and Plant Health Inspection Service.http://www.aphis.usda.gov/vs/nahss/equine/wnv/wnv_distribution_maps.htm.02/22/10.


Frequency of West Nile Virus•The number of WNV infections has significantly decreased since

2002.

•However, when WNV appeared in New York in 1999, it didn’t

take long for it to quickly spread throughout the Continental

United States.

•The maps on the following slide illustrate the great increase in

WNV cases between 1999 and 2002.

Frequency of West Nile VirusIn 1999, New York was the only state to report WNV infections. There were 25 cases.

In 2002, there were 15,257 reported cases of WNV.Note that Texas had the most cases: 1,699.



Frequency of West Nile Virus

2009


•In 2009 Texas only had 18 cases of

WNV.

•Washington had the most cases,

with 72. Horses are often traded

over the Canadian border. Another

data mining question might

investigate the reason why

Washington has so many WNV

cases.

Frequency of West Nile Virus

United States Department of Agriculture – Animal and Plant Health Inspection Service.http://nsu.aphis.usda.gov/nahss_web/arbovirus_county_level.faces?STATE=TX.02/22/10.

•This chart from the United

States Department of

Agriculture – Animal and

Plant Health Inspection

Service shows the cumulative

number of equine cases in

the state of Texas in 2009.

•Note the second column in

the graph: West Nile Virus

Cases.

•The majority of the cases in

Texas appear to occur in the

fall months.

Equine WNV Cases in Texas in 2009

This Excel file shows the total of West Nile Virus cases reported in Texas in 2009 and includes the month of earliest detection of the virus.

Equine WNV Cases in Texas in 2009

March6%

August22%

September22%

October50%

West Nile Virus Cases Per Month

January February March April May JuneJuly August September October November December

•This pie chart was

generated from the

Excel file shown on the

previous slide.

•50% of WNV cases

occurred in the month of

October.

•94% of WNV cases

occurred in the fall

months of August,

September, and October.

•As shown in the chart

on the previous slide,

there were a total of 18

WNV cases documented

in Texas in 2009.

Equine WNV Cases in Texas in 2009•By analyzing the data from the current year, one can say that

October is the month equines in Texas are at the most risk of being

bitten by an infected mosquito and getting West Nile Virus.

•However, many horses travel across several states for breeding,

showing, and trading purposes, so it is also important to know the

months that an equine is at the most risk of being bitten by an

infected mosquito throughout the Continental United States.

•The following slides explain the data mining used to create an

Excel spreadsheet that shows the number of WNV cases reported

each month for all states.

WNV Data Mining


•I referenced the United States

Department of Agriculture –

Animal and Plant Health

Inspection Service’s website to

find out how many cases of WNV

are reported each month in the

Continental United States.

•The site was most recently

updated December 9, 2009.

http://nsu.aphis.usda.gov/nahss_w

eb/arbovirus_summary.faces

•Only 36 states have reported

data.

WNV Data Mining•Each state has a chart showing

the number of reported cases of

WNV.

•For reference, here is a screen

shot of the cumulative number

of equine cases for Alabama.

As noted previously in this

presentation, the second

column is of interest.

•Each chart lists the date of

earliest detection of WNV in a

county.United States Department of Agriculture – Animal and Plant Health Inspection Service.http://nsu.aphis.usda.gov/nahss_web/arbovirus_county_level.faces?STATE=TX.02/22/10.

WNV Data Mining•I logged the total number of cases

per month in an Excel

spreadsheet.

•The chart does not give a total

per month, so first I had to log the

data by visiting each state’s

spreadsheet.

•Because of the chance of human

error, I could total the number of

cases I had logged in the monthly

columns and compare it to the

chart showing all state

information. That chart includes a

total number of cases per state for

the selected year.


WNV Data Mining•Continuing to use Alabama as an example, the previous chart

shows that Alabama had 11 reported cases of WNV in 2009.

•I took the information shown in the chart for Alabama and placed

it in an Excel spreadsheet to show how many cases were reported

each month.


WNV Data Mining•A note about the charts from the United States Department of

Agriculture – Animal and Plant Health Inspection Service:

The additional columns show the number of Eastern Equine

Encephalitis (EEE) cases and Western Equine Encephalitis

(WEE) cases.

There are common equine vaccinations for both of these

viruses, but the vaccines and viruses are unrelated to West

Nile Virus. Vaccinations against EEE and WEE provide no

protection against West Nile Virus.

The states that are listed in my Excel spreadsheet that have

zero reported cases of WNV are listed in the state list

because there have been cases of EEE or WEE reported in

one of the state’s counties.

WNV Data Mining•This Excel file

shows the number

of reported cases

per month of WNV

in 36 states.

•The source of

information was

the United States

Department of

Agriculture –

Animal and Plant

Health Inspection

Service.

WNV Data MiningMarch; 1

July; 78

August; 89

September; 44

October; 26

November; 3

JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember

•This pie chart illustrates

the number of cases of WNV

in the 36 states per month.

•There were a total of 241

reported cases of WNV in

2009. This total was not on

the website but was instead

discovered through data

mining.

•The small Excel file is the

file used to create this pie

chart. The data was

extracted from the main

Excel file shown on the

previous slide.

WNV Data MiningMarch; 1

July; 78

August; 89

September; 44

October; 26

November; 3

JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember

•There was one case of

WNV reported in Texas

in March. The remaining

240 cases occurred

between July and

November.

•The majority of cases

were reported in August.

August’s 89 cases

account for 37% of WNV

cases in 2009.

•July had the second

highest number of cases,

78, accounting for about

32% of the WNV cases in

2009.

U.S. Department of Agriculture- Animal and Plant Health Inspection Service.http://www.aphis.usda.gov/vs/nahss/equine/wnv/ada_wnv_2007.pdf.Viewed 2/24/10.

How to protect equines from WNV•The image to the right illustrates the

West Nile Virus transmission cycle.

•It can be difficult to isolate your horse

from mosquitoes, but there are

protective measures.

•The best ways to keep horses from

getting WNV is to:

Reduce the source (eliminate

mosquitoes)

Avoid the source (mosquitoes)

Vaccinate against the virus

How to protect equines from WNV•The best way to limit a horse’s exposure to infected mosquitoes is

to limit mosquito breeding sites.

Remove any potential sources of standing water

Clean water troughs

Clean clogged roof gutters

Turn over wheel barrows that are not in use

Manage property with landscaping to eliminate low spots

where standing water might collect.

Polyjumps.com.http://www.polyjumps.com/acatalog/TWtop.jpg.02/26/10

Vaccinating against WNV

U.S. Department of Agriculture – Animal and Plant Health Inspection Service.http://www.aphis.usda.gov/vs/nahss/equine/wnv/ada_wnv_2007.pdf.Viewed 2/24/10.

•The American Association of Equine

Practitioners (AAEP) recommends that all

horses in North America be immunized

against West Nile Virus.

•The risk of exposure to an infected

mosquito and the fact that mosquitoes

carry the virus make it difficult to predict

what regions of the country are most likely

to have infected mosquitoes.

•The AAEP recommends annual

revaccination in the spring, prior to the

peak WNV season.

•This supports my finding that the fall

months are the months with the most WNV

cases, meaning horses are at the most risk

for WNV infection during these months.

Is WNV under control?•The Texas Department of

State Health Services

provides annual statistics for

West Nile Virus in Texas.

•http://www.dshs.state.tx.us/

idcu/disease/arboviral/

westnile/statistics//annual/

default.asp

The annual summaries

include the number of

cases and counties related

to bird, human (virus and

fever), mosquito, horse,

and other West Nile Virus

infections.

Texas Department of State Health Services.http://www.dshs.state.tx.us/idcu/disease/arboviral/westnile/statistics//annual/default.asp.02/25/10.

Is WNV under control?•The Texas Department of State Health Service’s website has

Annual Summaries from 2009 to 2002. (2010 is available but has

zero cases.)

•The maps of the United States shown at the beginning of this

presentation showed that the number of WNV cases in equines

has decreased. However, mosquitoes are the main factor in

equine WNV cases.

•Therefore, the information on the Texas Department of State

Health Service’s website will allow me to see if WNV has

decreased among mosquitoes.

•I will take the chart information on cases of mosquitoes and

horses and compile it in an Excel spreadsheet.

Is WNV under control?•This Excel spreadsheet shows the number of cases of WNV in

mosquitoes and horses from 2002 through 2009.

Is WNV under control?

2009 2008 2007 2006 2005 2004 2003 20020

200

400

600

800

1000

1200

1400

1600

1800

MosquitoHorse

•The graph shows that

cases of mosquitoes

with WNV and horses

with WNV have

decreased.

•Please note that the

dates decrease in order

along the x-axis. (The

graph starts at 2009,

the most recent year.)

•I would like the site to

have included

information about how

they complied research

relating to the number

of mosquitoes carrying

WNV.


2009 2008 2007 2006 2005 2004 2003 20020

200

400

600

800

1000

1200

1400

1600

1800

MosquitoHorse

•It is interesting to note

that the number of

mosquitoes cases of

WNV decreased from

2007 to 2008 but then

increased again in 2009.

•The number of horse

cases of WNV only

increased slightly

between 2008 and 2009,

suggesting that

vaccinations are

effective even when

WNV is being carried by

large numbers of

mosquitoes.

Is WNV under control?•It is also interesting to look at the number of mosquito

and horse cases in a line graph form. Please note that this

time, the dates are sequential (from 2002 to 2009).

•Below is the Excel sheet used to create

the line graph.


2002 2003 2004 2005 2006 2007 2008 20090

200

400

600

800

1000

1200

1400

1600

1800

MosquitoHorse

•The line graph really illustrates the decrease in WNV infections from

2002 to 2009.

•It will be interesting to see if the number of mosquito cases continues

to increase in 2010.

•Hopefully horse and mosquito cases will decrease in the future years.

Answering the Question•The question asked at the beginning of this presentation was,

“How common is West Nile Virus and when is it a threat to

equines?”

•This question has two sections.

How common is West Nile Virus?

West Nile Virus is common enough that the American

Association of Equine Practitioners recommends that all

horses in North America receive an annual vaccination.

According to the American Association of Equine

Practitioners, WNV is considered to be endemic in all areas

of North America. The results of data mining shown in this

PowerPoint confirm this point.

Answering the Question When is West Nile Virus a threat to equines?

West Nile Virus is definitely a threat to

equines.

The American Association of Equine

Practitioners states that the mortality rate for

horses with signs of a West Nile Virus

infection is 33%.

The data shown in my graphs shows that

West Nile Virus is most frequent in the fall

months, so it is extremely important that

horses are vaccinated prior to those months,

ideally in the spring.

The line graph shows a decrease in WNV

cases in horses over the past 7 years.

However, WNV is still present, so it is still a

threat.

ReferencesAmerican Association of Equine Practitioners (2010). Retrieved February 25,

2010, from http://www.aaep.org/pdfs/AAEP_WNV_Guidelines_2005.pdf.

Center for Disease Control (2010). Retrieved February 23, 2010, from

http://www.cdc.gov/ncidod/dvbid/westnile/qa/wnv_horses.htm.

North East Independent School District (n.d.). Retrieved February 21, 2010, from

http://www.neisd.net/elmlang/images/j0189633.jpg.

Polyjumps.com (n.d.). Retrieved February 26, 2010, from http://www.polyjumps.com/acatalog/TWtop.jpg.

Texas Department of State Health Services (n.d.). Retrieved February 25, 2010, from

http://www.dshs.state.tx.us/idcu/disease/arboviral/westnile/statistics//annual/default.asp.

http://www.aaep.org/pdfs/AAEP_WNV_Guidelines_2005.pdf

http://www.cdc.gov/ncidod/dvbid/westnile/qa/wnv_horses.htm

http://www.neisd.net/elmlang/images/j0189633.jpg

http://www.polyjumps.com/acatalog/TWtop.jpg

http://www.dshs.state.tx.us/idcu/disease/arboviral/westnile/statistics/annual/default.asp





ReferencesUnited States Department of Agriculture – Animal and Plant Health Inspection

Service (n.d.). Retrieved February 22, 2010, from http://www.aphis.usda.gov/vs/nahss/equine/wnv/

wnv_distribution_maps.htm.

United States Department of Agriculture – Animal and Plant Health Inspection

Service (n.d.). Retrieved February 24, 2010, from

http://www.aphis.usda.gov/vs/nahss/equine/wnv/ada_wnv_2007.pdf.

http://www.aphis.usda.gov/vs/nahss/equine/wnv/wnv_distribution_maps.htm




http://www.aphis.usda.gov/vs/nahss/equine/wnv/ada_wnv_2007.pdf

Griest Data Mining

Health & Medicine

Transcript of Griest Data Mining