[Leish-l] S.O.S.

[Patrick Bastien]

Dear colleague,
1) The Leishmania (or any parasite) DNA has been shown to remain in  
the blood during a few hours only (in any case, less than 48 hs). By  
contrast, the main issue with PCR is carry-over contaminations, which  
can profoundly bias your results with false positives. You should  
always include several negative controls in your PCR tests.
2) The fact of finding more parasites in people with lower titers is  
not necessairy a surprise. We (an others) found the same thing in dogs  
(article attached). Although I am no good in immunology, I hypothesize  
that, because the 'good' protective immunity in leishmaniasis is  
cellular, the humoral immune response is somehow a sign of an  
inadequate response, compatible with the expression of the disease  
(?). I am sure that distinguished immunologists in this network will  
know how to explain this better than I do.
Regards
P. Bastien

Pr Patrick Bastien
Director, Departement de Parasitologie-Mycologie
Centre National de Reference des Leishmanioses
Vice-Director, "MiVEGEC" unit research UMR5290 CNRS/224 IRD/UM1/UM2
Faculte de Medecine, Université Montpellier 1
39 Av. Charles Flahault
34295 Montpellier cedex 5


----- Message de vmvaziri at gmail.com ---------
     Date : Wed, 29 Jan 2014 13:49:56 +0330
      De : Vahideh Moin Vaziri <vmvaziri at gmail.com>
Répondre à : Vahideh Moin Vaziri <vmvaziri at gmail.com>
  Objet : [Leish-l] S.O.S.
       À : leish-l at lineu.icb.usp.br


> Dear Friends
> Would you please help me to find the answer of following question kindly?
>
> Working on visceral leishmaniasis in a newly emerged hypoendemic foci in
> Iran we found  seropositive human blood samples at different titres by DAT.
> To characterize parasite, kDNA and ITS1 PCR were done. The result showed
> that in the samples with lower titer ( 1/400, 1/800) parasite were detected
> by PCR much more than ones with high titer ( 1/3200).
> I want to know, how long  *L. infantum* will persist in human blood after
> infection? I mean how long the DNA of parasite could be detected by PCR? Is
> it right to say that at the time that  we find high titer of antibody,
> parasite vanish from blood or not?
>
> Your kind cooperation is appreciated in advance.
> Best wishes
> --
> Vahideh Moin-Vaziri, Ph.D
> Department of Parasitology and Mycology,
> School of Medicine,
> Shahid Beheshti University of Medical Sciences,
> Post Code: 19395-4719
> Yemen Street,
> Chamran Expressway,
> Tehran, Iran,
> Tel: +98 21 23872564
> Fax: +98 21 22439962
> E mail: vmvaziri at gmail.com
>            vmvaziri at hotmail.com
>
> --
> This email was sent by icb.usp.br
>


----- Fin du message de vmvaziri at gmail.com -----


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