Tuesday, January 24, 2012

Toxoplasmosis


I thought the first zoonotic disease I’d cover would be Toxoplasmosis.  It's an infection that most people commonly associate with cats and pregnant women.  But as you will soon learn there are other ways you can become infected. 


What is Toxoplasmosis?


It's a disease caused by a parasite called Toxoplasma gondii.  It is estimated in the United States approximately 22.5% of the population 12 years and older are infected with the parasite and worldwide it has been estimated that in certain places up to 95% of some populations carry the parasite (CDC).  The majority of healthy people and cats infected with the parasite don’t have any symptoms.

How does one become infected?


There are three major modes of transmission 
  • Congenital - a woman newly infected during pregnancy can pass the infection to her unborn child  
  • Ingestion of undercooked contaminated meat, especially pork, lamb and venison 
    • Worldwide this is the cause of the majority of infections
  • Ingestion of oocyst passed in cat’s feces
    • Cats become infected by eating infected rodents, birds or raw meat and then pass the parasite in their feces in the form of an oocyst.
    • For as long as 3 weeks after becoming infected cats shed millions of oocysts in their feces.  Older cats are less likely to shed.
    • Most infected cats will not show any signs of illness. 
    • People become infected by:
      • Ingestion of oocysts when cleaning a cat’s litter box when the cat is shedding
      • Ingestion of oocysts in contaminated soil.  Remember not all cats use litter boxes!
        • Eating unwashed fruits and vegetables
        • Not washing their hands after gardening
      • Drinking contaminated water
  • Uncommon causes of transmission 
    • Blood transfusion 
    • Tissue or organ transplants


What does the disease look like?

  •  Healthy people as stated before who become infected generally have no symptoms.  If symptoms do occur they are  typically mild “flu-like” symptoms that last for a few weeks and then resolve.  The parasite will remain in the body in a latent form and can cause illness again if the person becomes immunosuppressed.
  • Immunosuppressed individuals can have more severe symptoms including fever, headache, nausea, and seizures.

  • Pregnant women

o   If a woman has already been infected prior to becoming pregnant the woman has developed immunity and the baby will be protected.

o   If a woman is pregnant and becomes newly infected she can then pass the infection on to the unborn child.  Congenital abnormalities for the child include abnormal enlargement or smallness of the head, potential vision loss, mental disability and seizures.
Prevention
  • Cook your food! 
    • Whole cut meat cook to at least 145
    • Ground meat at least 160 F
    • Poultry at least 165 F
  • Freeze meat at 0 F for several days prior to cooking.
  • Wash fruits and vegetables before eating.
  • Do not drink unpasteurized milk.
  • Drink clean water.
  • Wear gloves when gardening or when in contact with soil or sand and wash your hands after.


I’m pregnant do I need to give away my cat?


NO.  But you will want to take some extra precautions:

  • Have someone else change the litter box.  If no one else is available wear gloves and wash your hands well afterwards.  Remember transmission is fecal-oral, so washing your hands is key. 
  • Clean the litter box daily.   This is very important because the parasite does not become infectious until 1 to 5 days after it is passed in a cat’s feces.  So try to have someone clean the litter box right after your cat has defecated. 
  • Don’t feed your cat raw or undercooked meat.
  • Keep your cat inside. 
  • Do not get a new cat while you are pregnant and avoid contact with stray cats. 
  • You should also follow the above mentioned recommendations.

If you have any further questions or concerns please contact your veterinarian or physician.

Daily Digital

My little man Manny!

Rawhides - Why I Hate Them


The fourth year of vet school consists entirely of clinical rotations.  I tracked mixed animal so my rotations consisted of things such as small animal medicine, small animal surgery, large animal medicine, large animal surgery, radiology, anesthesiology, etc. No matter what you track (small animal, large animal or mixed animal) everyone is required to complete a necropsy rotation.  Which I’m sure to the average person sounds horrible but remember we’re veterinary students and we view it as a chance to learn.  However, I will admit the smell is horrible and no matter how many times you shower or how many times you wash your clothes the smell is still there.  So by the end of the rotation you end up throwing out every piece of clothing that you wore during that 2-week period.  Also, for whatever reason they have you dress all in white which makes absolutely no sense.  Anyway, the most rewarding cases were the ones that you immediately found the cause of the death and you didn’t have to wait for the results of histopathology or any further testing.  During my 2-week necropsy rotation there was one case that I will never forget.  A 4-year female spayed Pomeranian presented for sudden death at home.  According to the owner the dog was acting perfectly normal went outside for a few minutes, came back inside, suddenly collapsed and died.  When performing a necropsy there is a strict protocol you follow so nothing is missed.  I’ll spare you the details of the protocol but by the time I got to dissecting the larynx I had found the cause of the death.  A large round piece of rawhide was lodge in the larynx completely occluding the airway.  The pathologist in charge looked at me and said,  “this is going to be a hard phone call to make”.  I was devastated both for the dog and the owners.

After graduation I went into private practice and at least once a week we remove esophageal foreign bodies, usually rawhides.  Esophageal foreign bodies can be life threatening and need to be treated immediately.  The foreign body can cause severe injury to the lining of the esophagus including perforation, which is life threatening.  Potentially any type of foreign object can become lodged in the esophagus – bones, needles, fishhooks, rawhides, etc.  Clinical signs of esophageal foreign bodies include drooling, gagging, repeated attempts to swallow, pawing at the mouth, not being about to swallow food or water.  Many esophageal foreign bodies are easily seen on x-rays.  Once diagnosed esophageal foreign bodies should be removed immediately typically with a flexible endoscope or forceps.  If surgery is needed the overall prognosis is poor.  Complications associated with esophageal foreign bodies include stricture formation of the esophagus, severe and might I add painful inflammation of the esophagus, laceration of the lining of the esophagus and aspiration pneumonia secondary to regurgitation.

My advice is to completely avoid rawhide chews. There are many other great and safe alternatives.  I personally or I should say my dogs personally love kongs.  I also highly recommend supervising any dog with any type of chew toy.