Tularemia

[IreneF]

Here: 'I can't say it makes sense to me. You'dhave to make some assumptions about the prevalence of all these diseases.'

Also, you might be interested to know that there are two kinds of Tularemia, one (Type A) that is very virulent, as you said, and the other (Type B), which is less so.

Please read what I said in response to Valentijn. I didn't say say anything about the general population, unless you are referring to the general population of ticks.

 

[msf]

(Justy)

Hi Irene - Tularemia is transmitted by ticks. Often testing for Lyme disease is unreliable - so many people may not show positive on testing but do indeed have Lyme. Multiple chronic co infections (infections you get from the tick along with Lyme) point more strongly to the fact that you were bitten by a tick or perhaps mosquito etc and therefore DO have Lyme disease.

I have tested positive for Bartonella, Chlamydia pneumonia and now Tularemia - the chances I got all these (apart from the cpn) when being bitten by a tick are high, therefore I probably do also have Lyme - hope this makes sense?


(Irene)

I can't say it makes sense to me. You'dhave to make some assumptions about the prevalence of all these diseases.

My daughter is studying Lyme disease ecology. I'll ask her. She works with ticks, although I don't know if she tests them for anything more than Borrelia.


(Me)

You were responding to Justy, and the diseases you seem to be referring to are Bartonella, Chlamydia Pneumonia and Tularemia. If you were referring to their prevalence in ticks, I don't understand what point you were making, unless you were suggesting that you can get these infections from other sources. If the latter, I believe you are correct, but I think the point that Justy was making was that the chance of having one of these without having being bitten by a tick would be fairly high, but the chance of having all three without having been bitten by one would be much lower (probabilities are multiplied, not added, as I'm sure you know). Also, I don't know how many people get Tularemia directly from rabbits or other small mammals, but I would guess that it wouldn't be many - I imagine that any rabbit Justy was in close contact with would be a pet bought from a petshop, and therefore unlikely to have Tularemia.

 

[IreneF]

No, what I was saying was that if you test positive for tick-transmitted infection A it doesn't follow that you necessarily have tick-transmitted infection B, especially if you don't test positive for it. You would need to know the prevalence of B in people who actually have A.

Furthermore, some tick-transmitted infections can be acquired through other vectors, by inhalation, by eating infected meat, or through cuts in the skin.

And then there's the issue of false positives in testing. Tularemia, for example, cross-reacts with Bartonella. I don't think there's any disease test that's 100% reliable.

 

[msf]

Well, I think I dealt with your second point, but I didn't know that Tularemia can cross-react with Bartonella. Re: your first point, I'm pretty sure KDM doesn't suspect Justy has Lyme just because she has those co-infections, but rather because of the whole clinical picture, which takes into account the likelihood of having all (or two) co-infections without a tick-bite, but also a lot of other things - I believe Justy also had a not totally negative result on the LTT test too, so if you were the doctor, which diagnosis would you pursue? Or would you just say that she isn't clearly positive for anything and therefore that you didn't know what was wrong with her? I'm pretty sure she could have found someone in the UK to do that.