CLL Topics Banner: Therapies, Research and Patient Education for Chronic Lymphocytic Leukemia
CLL Topics Home Navigation Topics Alert Learning Tools About Us Feedback Feedback
Full Menu

Topics Alert

world balloon

Topics Alert Archive

Alert Number 308

Toxoplasmosis (Cat Lovers - Beware!)

Date: December 6, 2008

A few days ago I received a heart-breaking letter from one of our members.  Her father had been doing great after a stem cell transplant, everything pointed to a wonderful success story.  Out of the blue, a sudden infection raged out of control and her father passed away in a matter of days.  Perhaps it is the similarity to Harvey's Journal  that caught my eye. Our family went through a similar heart-wrenching tragedy when my husband PC passed away in June of this year after an unidentified infection played havoc with his newly engrafted immune system.  Even after the autopsy they have not been able to identify the culprit pathogen that killed my sweetheart.

In the case of our member, the story was a little clearer.  The infection was caused by toxoplasmosis.  If you are a cat lover, you have probably heard of this particular pathogen.  As seriously immune compromised patients all of us should be aware of this bug – once again, I would like to remind you that life with CLL is no walk in the park, what you don’t know can kill you.

Toxoplasmosis – a lurking danger

Toxoplasmosis is caused by protozoa called toxoplasma gondii.  Cats are the major reservoir of this particular bug.  You can get it by eating infected meat that has not been properly cooked, or by coming in contact with infected cat poop.  It can also be transmitted from mother to fetus.

Roughly a third of the world population carries a latent infection of toxoplasma gondii – and once infected, you carry it for life. In healthy people with fully functioning immune systems it causes little more than mild flu like symptoms.  But in folks with AIDS or other immune dysfunction diseases like CLL, it can play a very dangerous role, especially if the patient has just gone through immune suppressive therapy with drugs such as fludarabine, Campath etc, or the massive cocktail of drugs used in stem cell transplants. Initial symptoms of acute toxoplasmosis are swollen lymph nodes, muscle aches, flu like symptoms.  A sophisticated pcr (polymerase chain reaction) blood test is needed to confirm toxoplasmosis.

This is one tough bug to kill.  It can survive freezing temperatures, disinfectants, even household bleach, and can survive dormant in the environment for more than a year.  The one thing that kills it is high temperature, higher than 150F (66C) – hence the need to eat only meat that has been cooked well.

Cats and toxoplasmosis

It is well documented that cats are the natural reservoir of this particular protozoa.  If your cat is an outdoor cat that likes to hunt and eat its prey, chances are higher that it has been exposed.  Infected cats then shed “oocysts” in their feces.  Who does the job of cleaning out the litter box in your family?  Most of us have heard enough about this particular danger that the duty is often picked up by a family member, not the CLL patient.  If that is the case, how careful are you to clean your hands afterwards?  I am afraid a cursory pass of your hands under the tap is not enough.  Remember, this bug is one tough customer and it cannot be controlled even by household bleach.  What to do?  I strongly urge that even family members cleaning the cat litter use disposable gloves while doing this less than pleasant chore, and dispose of the litter and gloves immediately. Try doing it far away from living quarters and without raising a lot of dust.  Then there is the whole other question of what one does about the paws of your furry friend.  Cats love to scratch and dig around their litter box before they do their thing, followed soon after by purring contentedly  in your lap. I am afraid I have no good solutions to protect CLL patients from that potential risk.



Here are some of the not-so friendly effects of full blown toxoplasmosis infection in immune compromised people:

  • Encephalitis (inflammation of the brain)
  • Neurological disease
  • Disease of the heart, liver
  • Eye disease
  • Death

Behavioral changes are frequently observed in patients with active infection, probably because of brain involvement.  Here is an interesting tidbit: “studies have found that toxoplasmosis is associated with an increased car accident rate, roughly doubling or tripling the chance of an accident relative to uninfected people. This may be due to the slowed reaction times that are associated with infection. "If our data are true then about a million people a year die just because they are infected with toxoplasma," according to the researcher Jaroslav Flegr.  Treatment is a cocktail of potent antibacterial drugs, but it is not very effective.

You can read more about toxoplasmosis by clicking on the wiki link below.  The second link is to the 2007 ASH Education review article on the infectious complications in CLL patients.  You can get the full article just by clicking on this link and in my opinion it is almost mandatory reading for CLL patients and their care givers.  If today is not a good day to read this stuff, at the very least file it away for future reference.

Infectious Complications in CLL Patients


No one knows better than me the emotional ties that bind us to our pets.  Often they are as important to us as our children.  They give companionship, love and warmth that make them indispensable members of our families.  I know. I would have a hard time waking up in the morning and getting out of bed but for our beloved Australian Shepherd dog Jasper. She keeps me sane when the world seems so dark and lonely, she battles the demons of loss and grief right alongside of me.  If anyone understands how I feel after losing my husband, it would be Jasper.  She was PC’s dog - his faithful companion on many a good hike.  Se was his therapy dog, chasing away the blues as she chased after balls and Frisbees.  She still waits for him to come home. She whines eagerly by the garage door when a particular vintage Honda similar to PC’s car drives past our house. One night recently I found her curled around the wide brimmed hat PC wore for many years (it was almost his trademark around town!), gently licking and grooming it.  How does one repay love and devotion like that?

I am a dog person, but there are cat people out there to whom their cats are just as important.  I am not going to tell you to get rid of your furry children.  But you need to know the risks you are taking, the precautions that can reduce the risks, and be smart about telling your oncologist about your interaction with your pets.  I strongly urge patients undergoing chemotherapy of any kind to refrain from close contact with cats or their litter boxes.  If your cat is a truly indoor cat with no exposure to rodents out in the wild, you may be at reduced risk.  Or so I hope.

This alert is dedicated to the memory of our member’s father.  He was just about the same age as PC, lots to live for and far too young to die.  He will be missed, as PC is, by his loving family.

Be well,


NOTICE: This page from the Topics Alert archive was originally emailed to subscribers of Topics Alert, a free service of CLL Topics Inc. If you are not a subscriber and you wish to receive email Alerts, please register at the Topics Alert subscription page. The content of this page is intended for information only and it is NOT meant to be medical advice. Please be sure to consult and follow the advice of your doctors on all medical matters.

Go to Alert Archive Listing

You may also retrieve a different Alert,
by entering a new Alert number here
(in the range 1 to 309)



Disclaimer: The content of this website is intended for information only and is NOT meant to be medical advice. Please be sure to consult and follow the advice of your doctors on all medical matters.

Copyright Notice:

Copyright © 2002-2007 CLL Topics, Inc. All Rights Reserved.

All materials contained on this site are protected by United States copyright law and may not be reproduced, distributed, transmitted, displayed, published or broadcast without the prior written permission of CLL Topics, Inc. You may not alter or remove any trademark, copyright or other notice from copies of the content.

However, you may download and print material from exclusively for your personal, noncommercial use.




up arrow