Sunday, September 2, 2012

Fall 2012 News & Notes

High Desert Veterinary Service

Chrysann Collatos VMD,PhD,DipACVIM

775-969-3495 (Office) 742-2823 (Emergency)
Fall 2012 News & Notes:
Ø Vaccination Clinic Schedule
Ø Special Alert: West Nile & Flu
Ø Understanding Immunity
Another season changes-
     Here I am enjoying the view with Washoe, a 9 yo Arabian gelding, during the 50 mile Bridgeport Endurance ride a few weeks ago.  This was my first “50” and we proudly finished with all “A’s” for Washoe’s condition at every vet check.  When the ride vet said Washoe looked ready for another fifty miles, I looked at her and asked, “but what about ME?”      Endurance riding is a fascinating sport.  I am avidly devouring the literature on conditioning, electrolyte balance, hydration, metabolic and musculoskeletal challenges from a veterinary view point.  My experiences over the years as a participant in the worlds of Thoroughbred racing, show jumping, foxhunting, and now endurance riding  provide invaluable knowledge to me as a veterinarian.  Understanding equine athletes of various disciplines and the sports they “play” from an insider’s perspective gives me special insight into their injuries, illnesses and daily stresses that makes me a better clinician for them.
            Enough about me – Hayley, my assistant you all have known for the past 6 years, was accepted into Washington State Veterinary School and began her first semester last week.  Please join me in wishing her all the best as she continues onward in her veterinary career.  And Jessie is just now returning from Nicaraugua, where she volunteered as a veterinary technician in training with an international veterinary non-profit organization working both with small animals and equines in third world countries.  She will finish her vet tech program at TMCC this year while continuing to work part time between classes.
          Join me in welcoming Victoria and Jessica, my two new assistants, to the practice.  Victoria is a student at TMCC and plans to pursue a career as a Licensed Veterinary Technician.  Jessica, already a LVT, is finishing her final year at UNR.  After graduating she plans to spend  a year working with me as she applies to vet school for Fall 2014 start date.
That’s the latest news from us.  I look forward to hearing your summer adventure stories when I see you at your Fall Clinic.

Dr. Chrysann
or e-mail

Special Alert Concerning Fall Vaccinations
Significantly increased occurrence of two diseases may affect your decisions concerning Fall vaccinations this year.  First, human cases of West Nile Virus are the highest nationwide since 1999, with 693 cases reported as of the 2nd week of August, including cases in CA and one asymptomatic human carrier in NV.  Horse cases also are on the rise nationwide, with 77 cases including horses in AZ, CA, CO, NM, WY and one fatality here in Nevada in Churchill County.  So, if you were economizing this spring and failed to have your horses vaccinated against West Nile Virus, I strongly recommend a West Nile Virus vaccine as part of your fall horse care.  Mortality in horses with West Nile Virus Encephalitis can reach 40% and vaccination is safe and effective.  Late summer/early fall is the highest risk period for West Nile Virus disease in horses.
Secondly, there have been multiple outbreaks of high fevers and respiratory disease in horses due to Equine Influenza Virus both in the North Valleys and Washoe Valley this summer.  Interestingly, Dr. Nicola Pusterla from the UC Davis PCR diagnostic center contacted me because the virus strain in one of these outbreaks was genetically identical to a strain identified in a group of horses in Oregon.  We were unable to identify any travel that connected the two groups of horses.  While we know that West Nile virus travels across the country in migrating bird populations, we still do not understand how Equine Influenza virus seems to appear suddenly in areas without any identifiable vector, or means of transportation.
Here are my specific recommendations for 2012 regarding these two diseases and fall vaccinations:
West Nile Virus – If your horse has not received a West Nile Virus Vaccine in 2012, I strongly recommend fall vaccination against West Nile Virus.

Influenza/Herpes (Flu/rhino) - I recommend a flu/rhino vaccination for your horse this fall if it meets any of the following criteria:  1)Your horse is 5 years of age or less,  2) Your horse lives in a neighborhood with lots of horse movement along streets/trails or with a shared horse arena, 3)Your horse lives in a boarding stable.

Understanding Flu and Immunity
Equine influenza shares many similarities with the human flu virus we all fight every fall.  The equine virus exists worldwide, except in New Zealand and Iceland.  Clinical signs include fever, depression, poor appetite, cough and nasal discharge.  The virus only lives a short time in the environment and is susceptible to common disinfectants.  In most cases the virus is spread from horse to horse in aerosolized particles generated when an infected horse coughs.  Unfortunately, virus replicates in the horses upper respiratory tract and is shed into the environment for a few days before clinical signs become apparent, making control of disease outbreaks challenging, especially in larger groups of horses.
The virus has many serotypes, and these strains change frequently.  The horse must have antibodies specific to each serotype to prevent disease.  I imagine the flu virus as a secret agent – every time he appears he is wearing a different hat and coat so I don’t recognize him until it is too late…..and here I am coughing and sneezing, or watching my horse cough and hang his head.  Both we and our horses manufacture antibodies that are shaped to fit the “hat and coat” of each flu strain that infects us – when exposed to a virus strain wearing a new “hat and coat” the old antibodies may not eliminate the new virus effectively and we get sick all over again.  Don’t get confused here – equine influenza virus and human influenza viruses share the same infection tactics, but not the same host – we cannot get flu from our horses, or visa versa.
Pharmaceutical companies making vaccines against Equine Influenza know that in order for their vaccine to be effective, it must contain the most up to date viral strains in a given location.  They weigh this against the cost of introducing new strains into their current vaccine.  Currently, the newest equine influenza virus strains predominant in the US include viral antigens (the “hat and coat”) from strains A/South Africa/2003 or A/Ohio/2003.  The Merck influenza vaccine used in our practice contains A/KY 93, KY02, and NM2/93 strains. Merck Animal Health serological data suggest that these strains provide cross protection against Ohio 03 and South Africa 03. So Merck has not yet taken the financial dive to replace the strains of influenza virus in their vaccine, but they have tested them and claim that there is cross protection – in other words the antibodies created in response to their vaccine will recognize newer influenza strains in our horses’ environment.
You can see that Equine Influenza Vaccines are not perfect – so why should we use them?  They are an important part of disease prevention in specific settings.  If only  part of a population of horses is vaccinated, these individuals may have partial immunity which protects them from showing signs of disease but does not completely eliminate their shedding of virus.  Horses, especially younger ones, living in groups without diligent vaccination rapidly spread virus from one to another making it very difficult for humans in charge to stay ahead of disease spread.  In larger barns, the outcome is usually quarantine of the entire facility for 21 days or longer, or until 7 days after the last horse has any clinical signs or fever.   As you can imagine, such an outbreak has serious impacts, both on horses’ health and humans’ pocketbooks. The risk of pneumonia and other serious complications increases dramatically in such settings.
If a group of horses ALL are vaccinated against influenza the consequences of infection with flu virus are greatly reduced.  Although equine influenza vaccines may not be absolutely protective, they do reduce the virus’ ability to replicate in each horse, and therefore reduce the number of virus particles released into the environment and passed from horse to horse.  If EVERY horse in a given population is vaccinated, then the viral load in the vicinity is kept low, fewer horses actually contract disease, and the outbreak event is over much sooner, with fewer sick horses.  

Fall Vaccination Clinic Schedule

I am always here to answer your questions, and offer routine health care services on clinic days. Fall health care includes Flu/Rhino vaccination plus deworming or fecal examination, an oral exam,  and sheath cleaning.  Also West Nile Vaccination if not given in spring!
To reserve an appointment, call the office (775-969-3495) and leave:
Name, Phone #, Clinic Date,
Number of Animals, and Services requested.
We will return your call three days before your clinic with an estimated time of arrival at your address.  Please be sure horses are caught and haltered 30 minutes beforehand!

Location                                               Date
Rancho Haven/Sierra Ranchos1 -  Fri  Sep 14        
Rancho Haven/Sierra Ranchos2 - Sat Sep 22
Red Rock North/Silver Knolls 1 - Sun Sep 16          
Red Rock North/Silver Knolls 2 - Fri Sep 21
SpanSprings/Palomino Valley 1 - Sat Sep 15           
SpanSprings/Palomino Valley 2 - Fri Sep 28
Antelope/Golden/Lemmon Valley 1 - Sun Sep 23      
Antelope/Golden/Lemmon Valley 2 - Thur Sep 27
South & West Reno 1 - Sun Sep 23                        
South & West Reno 2 - Fri Sep 29
Sierra Valley/California - Sat Sep 30

 For additional savings, you can schedule your own mini-clinic as long as you have at least 6 horses at a single location.  Call the office to make such arrangements.

Discounted Price List – Clinic day only
Farm Call/Fall Exam                    $15.00
West Nile                                     $32.00
FluRhino                                      $27.00
Rabies                                         $21.00
Tetanus/ Encephalitis                    $15.00
Intranasal Strangles                      $32.00
Ivermectin Deworm                       $14.00
Coggins Test                                $27.00
Sheath Clean w/sedation               $45.00
Fecal parasite exam                      $18.00
Oral Exam (w/o sedation)              No charge!

If I offer an educational seminar series this winter will you come and participate?  I need your input – send suggestions for location and topics.  I am, as always, grateful for your patronage.

Don’t forget to make your clinic appointment today !

I believe that education is the key to evolution. I believe that animals are the key to compassion. I believe that learning never stops.

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