Possible protective immunity in human opisthorchiasis

Chronic infections with the liver flukes Opisthorchis viverrini and Clonorchis sinensis affect over 30 million people in southeastern Asia. With ongoing exposure, reinfection readily occurs following curative treatment and cumulative infections result in significant morbidity and a predisposition to cholangiocarcinoma. Though protective immunity has never been described in human opisthorchiasis, heterogeneity in worm burden occurs and a small number of exposed residents of endemic areas remain apparently uninfected. To explore the nature of this heterogeneity, we compared levels of serum antibody (Ab) to O. viverrini measured by an enzyme-linked immunosor-bent assay in 83 stool egg-positive and 49 stool egg-negative residents of an O. viverrini-endemic area in Thailand. Compared to the egg-positive residents, the egg-negative group had significantly higher levels of immunoglobulin (Ig)G, IgA and IgM to adult worm homogenate (AWH) and total Ab to metacercaria homogenate (MH). Furthermore, immunoblot analyses revealed that a significantly higher proportion of sera from the egg-negative residents had IgA reactivity against a 38-k Da AWH antigen and IgM reactivity against carbohydrate epitopes of a 42-k Da AWH glycoprotein antigen. These findings support a hypothesis that the egg-negative group includes individuals who may be immunologically resistant to this usually chronic infection.     

TRAINING HEALTH PROFESSIONALS IN CARING FOR DYING CHILDREN AND GRIEVING FAMILIES

In most industrialized countries today, the death of a child is a rare phenomenon. When it occurs, however, it is usually within a hospital setting, after the child has received complex and often long-term medical care aimed at curing or controlling a serious disease. Thus, health professionals are increasingly exposed to the dying process and death of a child with little prior education to help them deal with the particular needs of young patients and minimal preparation in recognizing and handling their personal reactions in the face of death. Comprehensive training programs in pediatric hospice care could help professionals cope with the growing and unique needs of terminally ill children and of their families but these should be differentiated from training programs designed for the terminal care of adult patients. The purpose of this article is to describe and discuss some of the challenges involved in the training of health professionals (pediatricians, nurses, psychologists, social workers, clergy) who wish to provide services to dying children and grieving families. These challenges include (a) definition of educational objectives, (b) selection of teaching methods and content of training, (c) definition and teaching of emotional involvement, (d) support of training participants, (e) promotion of interdisciplinary collaboration, (f) evaluation of the training process and its outcomes, and (g) background and skills of educators. The challenges are discussed and references are made to illustrate how they were met by a 600-hour training program on home-based palliative care for children dying of cancer conducted at the University of Athens.