Apr. 15th, 2008

spiceofbroadway: (Default)
I work for the Ontario government at the Ministry of Natural Resources. MNR is the ministry that tracks rabies, and it runs a pretty aggressive rabies eradication program (vaccine-filled baits, distributed by airplanes, are used to vaccinate wild animals over a large area). For the curious, it's worked pretty well in controlling the fox and raccoon strains of rabies in Ontario. It doesn't work so well with bats since they eat insects in the air, not bait on the ground.

I thought I read on one email list or another that MNR also tracked leptospirosis, which was news to me. As this is the disease that has been most on my mind lately, I figured I'd look into it. I sent out enquiring emails from my work account, got passed around a fair bit, and finally learned that lepto is not tracked in Ontario.

My email eventually got forwarded to Dr. John Prescott at the University of Guelph, a vet who researches lepto, among other things. I have a pretty broad scientific background, but it unfortunately does not include things like immunology and whatnot. So although Dr. Prescott did his best to answer my questions, I confess that I don't fully understand what he wrote. Still, I will put it here for the record and so that I can reference it later on.

He wrote his answers to my questions in all caps, which I find hard on the eyes, but I'm not going to retype everything he wrote just to change it to lower case.

~*~

Kristina: I know that lepto vaccines for dogs cover only four lepto serovars, and I've read that there are many more serovars than this, some of which are on the rise in Ontario.

Dr. P: THE VACCINE COVERS THE GREAT MAJORITY OF THE SEROVARS THAT CAUSE DISEASE IN DOGS, BUT DOES NOT HOWEVER INCLUDE BRATISLAVA, WHICH MAY CAUSE SPORADIC CASES IN DOGS. IT DOES NOT INCLUDE HARDJO, WHICH S A CATTLE/SHEEP SEROVAR THAT DOESN'T SEEM TO CAUSE CANINE LEPTO.

ONE QUESTION ABOUT THE VACCINE RAISED IS WHY IT DOESN'T INCLUDE AUTUMNALIS. IT SEEMS THAT THE "AUTUMNALIS-REACTING" DOGS ARE PART OF THE VERY BROAD CROSS-REACTIVITY AND HYPERAGGLUTINATING NATURE OF AUTUMNALIS. I DON'T BELIEVE THAT AUTUMNALIS OCCURS IN ONTARIO.

Kristina: I'm interested in finding out how many cases of diagnosed lepto are caused by the serovars covered by the vaccine and how many are caused by the others.

Dr. P: IMPOSSIBLE TO SAY BASED ON OUR CURRENT DIAGNOSTIC APPROACHES, THAT ARE LARGELY SEROLOGICAL, BUT I THINK THAT 95% OR MORE OF CANINE LEPTO ARE CAUSED BY SEROVARS IN THE VACICNE, SPECIFICALLY GRIPPOTYPHOSA AND THEN POMONA.

Kristina: I'm particularly interested in the Peterborough/Bancroft area, but I know many folks who would be interested in this sort of information from anywhere in Ontario (or even Canada, for that matter). Does the University of Guelph collect data of this sort? (MNR apparently does not.) If yes, has it been published or is it shareable?

Dr. P: AGAIN, IMPOSSIBLE TO SAY BASED ON SEROLOGY AND THE CROSS-REACTIVITY OF EARLY CANINE LEPTO SERA BECAUSE OF IgM CROSS-REACTIVITY, BUT PETERBOROUGH AREA HAS BEEN WHERE WE HAVE SEEN HYPERACUTE LEPTO IN DOGS. I DON'T KNOW WHETHER THIS IS BECAUSE OF SOME LEPTO-AWARE VETS IN THE AREA (THIS IS PART OF IT) OR WHETHER THERE'S MORE RACCOON AND SKUNK INTERACTION OF DOGS IN THE AREA. OTHER PEOPLE HAVE THOUGHT IN THE PAST POSTULATED THAT CANADIAN SHIELD PROMOTES LEPTO BECAUSE OF ALKALINE?? NATURE OF THE SOIL ALLOWING GREATER SURVIVAL OF THE ORGANISM IN THE ENVIRONMENT ONCE IT'S SHED BY THE CARRIERS IN THEIR URINE. THIS WAS BARBARA KINGSCOTE'S THEORY FROM 40+ YEARS AGO.

[Note from Kristina: The Canadian Shield is predominantly granite, which would make the soils acidic, not alkaline. He's a vet, not an environmental chemist.]

HOPE THIS HELPS; LOTS OF QUESTIONS, PRECISE ANSWERS DIFFICULT BECAUSE ONE IS EXTRAPOLATING FROM SEROLOGY AND GENERAL KNOWLEDGE OF LEPTO.

CANINE LEPTOSPIROSIS IS FOUND THROUGHOUT ONTARIO, AND PREVALENCE DOES TO SOME EXTENT REFLECT AWARENESS OF VETERINARIANS.

~*~

Not understanding all of that, I sent him a second message for clarification:

Kristina: Thanks so much for your message. My questions come from both professional and personal interest. I work for MNR, and I know that rabies is tracked here. I was wondering if lepto was as well, since it can be transmitted to humans, but apparently it's not. Do you know if there are many cases of people contracting lepto from their infected pets? In your opinion, do you think it should be tracked?

I THINK LEPTO IN DOGS SHOULD BE REPORTABLE BECAUSE OF THE HUMAN RISK

LOOK UP CANADIAN MEDICAL ASSOCATION JOURNAL ON LINE FREE

Prescott, J. F. 2008. Canine leptospirosis in Canada: A veterinarian's perspective. Can Med Assoc J 178:397-398.

Brown, K., Prescott, J. F. 2008. Leptospirosis in the family dog: A public health perspective. Can Med Assoc J 178: 399-401.


Kristina: The personal interest side comes from being an owner of a Nova Scotia duck tolling retriever. Tollers seem to experience more autoimmune disorders and adverse reactions to vaccinations than other breeds, so many Toller breeders recommend a limited vaccination protocol that doesn't include lepto. Lepto vaccines have a reputation (at least, within the Toller community) for causing more adverse reactions than most other vaccines, and they only provide immunity for several months and must be repeated annually, so it's regarded as not worth the risk. My mother's dog, a Sheltie/Corgi mix, had a terrible autoimmune reaction to Fort Dodge's lepto vaccine when it first came out several years ago and now can't be vaccinated against anything at all. (Fortunately, she's a fairly inactive older dog, and the thing she's most likely to pick up is a case of frostbite in winter.)

Dr. P: TOO BAD, NOT HEARD OF THIS

Kristina: On the other hand, my vet here in Peterborough has had several cases of lepto in the past few years, and I recently heard of a Toller in this area who died from leptospirosis.

Dr. P: RIGHT, PETERBOROUGH MAY BE HOT

Kristina: What is "hyperacute lepto" in dogs?

Dr. P: DIE IN ONE DAY OF SEPTIC SHOCK

~*~


Die in one day of septic shock? Gah! How am I supposed to weigh that against Jilly's very bad autoimmune reaction to Fort Dodge's vaccine?

Increased interaction between raccoons and dogs in this area? You could say that. We came home from the cottage one weekend last fall to discover five raccoons on our roof. Jim climbed up there and knocked one off with a shovel. The others fled.

I wonder if I can convince Jim to move out of the Peterborough area? To Mars, maybe. I bet there's no lepto at all on Mars! :-/

I guess my next step is to read the two papers he referred to (and hope I can understand them), and then call some local vets to find out how many cases of lepto they've actually seen and what the outcomes were. I'll also talk to Liz about it on Sunday. She lives in Bobcaygeon, which isn't far from Peterborough, and has lots of dogs in the field. I'm pretty sure she doesn't vaccinate against lepto.

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