Schistosomes are parasitic flatworms that cause schistosomiasis, a neglected tropical disease that affects hundreds of millions worldwide. Treatment and control of schistosomiasis relies almost entirely on the single drug praziquantel (PZQ), making the prospect of emerging drug resistance particularly worrisome. This review will survey reports of PZQ (and other drug) resistance in schistosomes and other platyhelminths, and explore mechanisms by which drug resistance might develop. Newer genomic and post-genomic strategies that offer the promise of better understanding of how drug resistance might arise in these organisms will be discussed. These approaches could also lead to insights into the mode of action of these drugs and potentially provide markers for monitoring the emergence of resistance.

Fungal pathogens are using several mechanisms to circumvent the inhibitory actions of antifungal drugs. The variety of these mechanisms was revealed in recent years by several laboratories with molecular approaches. Besides the identification of genes involved in antifungal drug resistance and the discovery of alternative pathways of resistance (i.e. biofilm formation), novel concepts in the understanding of the survival of fungal pathogen in the presence of antifungal drug (antifungal tolerance) have emerged.