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(Coordinator : Z. Pawlowski)
Minutes of the meeting held on November 7th, 1997 at the XVIII Congress of Hydatidology in Lisbon, Portugal
Present : Drs Andersen, USA ; P Graig, UK ; J Eckert, Switzerland ; D Heath, New Zealand ; B Holcamn, Uruquay ; P Kern, Germany ; Z Pawlowski, Poland (Chairman) ; P Schantz, USA; J Stefaniak, Poland ; A Thompson, Australia ; T Todorov, Bulgaria
This was the first working meeting of the Natural History Group, organized by Professor Z. Pawlowski on behalf of Professor D. Vuitton, the Groups coordinator. It has been agreed that the interest of the Group will focus first on cystic echinococcosis in humans, especially on the early cystic stages localized in the liver. Echinococcus granulosus cysts of other locations and E. multilocularis lesions in humans will be included later.
It has been agreed that the following studies can be performed to elucidate the early development stages of E. granulosus cysts :
* in order to gain more information on the proportions of the population exposed to the E. granulosus eggs and developing the infection, a test using recombinant oncospheral antigen should be prepared and included into the mass screenings together with the clinical, imaging and other immunological tests. The results may give a basis for further genetic and immunological studies in a part of population resistant to clinical CE. Professor Craig and Heath have expressed an interest in developing such a recombinant test.
It has also been agreed that
* Much information about the development of E. granulosus cysts in humans can be gained easily by collecting the following information during the population studies : age and sex, nutritional and immunological status, occupation and address of the screened individuals and location, size, number of the parasitic cysts as well as the cyst type at imaging according to the new standardized classification. The most important are the two parameters : population age and parasitic cysts type found at a screening.
* The longitudinal study observing the development of the cysts in a number of individuals may not be acceptable because of ethical reasons, however such information is frequently available in individual clinical cases and, well documented, may by useful for better understanding the development and evolution of E. granulosus cysts in humans.
* Samples of the hydatid fluid collected at PAIR or diagnostic punctures should be frozen and more widely used for immunological studies and detection of anthelmintic levels as proposed by Professor Eckert.
* Studies of clinical, imaging and immunological markers of the E. granulosus cysts biological activity are strongly encouraged. It seems that a good proportion of the E. granulosus cysts is spontaneously degenerating and/or less active and may not need any intervention or treatment. The up-dated list of such markers, prepared by Professor Pawlowski, is still fragmentary and has to be extended further.
Dr Pawlowski suggests to distribute the minutes of this meeting through the Informal WHO Groups channels to the participants and all people interested in the natural history of echinococcosis in humans. He also would be grateful for any further comments and suggestions related to the natural history of E. granulosus cysts as well as the information about any activities carried out in this direction.
Encl. Copies of 2 tables from Pawlowski, In : Compendium of cystic Echinococcosis, Eds Anderson et al. Bringham Young University, Provo, 1997, pp: 119-135, and of a table from Perdomo et al. Acta Tropica 1997;64:109-122.
Editor's note: Pictures from the paper version of Echinonews will be added as soon as possible .
