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Herpes simplex virus types 1 and 2 HSV1 and 2, namely varicella-zoster VZV and cytomegalovirus CMV, are among the most common pathogens worldwide. They remain in the host body for life. The course of infection with these viruses is often asymptomatic or mild and self-limiting, but in immunocompromised patients, such as solid organ or bone marrow transplant recipients, the course can be very severe or even life-threatening. Unfortunately, in the latter group, the highest percentage of infections with strains resistant to routinely used drugs is observed. On the other hand, frequent recurrences of genital herpes can be a problem even in people with normal immunity. Genital herpes also increases the risk of acquiring sexually transmitted diseases, including HIV infection and, if present in pregnant women, poses a risk to the fetus and newborn. Even more frequently than herpes simplex, congenital infections can be caused by cytomegalovirus. We present the most important anti-herpesviral agents, the mechanisms of resistance to these drugs, and the associated mutations in the viral genome. Special emphasis was placed on newly introduced drugs such as maribavir and brincidofovir. We also briefly discuss the most promising substances in preclinical testing as well as immunotherapy options and vaccines currently in use and under investigation.

Human microsporidiosis, a serious disease of immunocompetent and immunosuppressed people, can be due to zoonotic and environmental transmission of microsporidian spores. A survey utilizing conventional and molecular techniques for examining feces from 570 free-ranging, captive, and livestock birds demonstrated that 21 animals shed microsporidian spores of species known to infect humans, including Encephalitozoon hellem (20 birds; 3.5%) and Encephalitozoon intestinalis (1 bird; 0.2%). Of 11 avian species that shed E. hellem and E. intestinalis, 8 were aquatic birds (i.e., common waterfowl). The prevalence of microsporidian infections in waterfowl (8.6%) was significantly higher than the prevalence of microsporidian infections in other birds (1.1%) (P < 0.03); waterfowl fecal droppings contained significantly more spores (mean, 3.6 ؋ 10 5 spores/g) than nonaquatic bird droppings contained (mean, 4.4 ؋ 10 4 spores/g) (P < 0.003); and the presence of microsporidian spores of species known to infect humans in fecal samples was statistically associated with the aquatic status of the avian host (P < 0.001). We demonstrated that a single visit of a waterfowl flock can introduce into the surface water approximately 9.1 ؋ 10 8 microsporidian spores of species known to infect humans. Our findings demonstrate that waterborne microsporidian spores of species that infect people can originate from common waterfowl, which usually occur in large numbers and have unlimited access to surface waters, including waters used for production of drinking water.Microsporidians are obligate intracellular parasites that are emerging opportunistic pathogens that infect both immunocompromised and immunocompetent people (41,42,43). Microsporidians are on the Contaminant Candidate List of the U.S. Environmental Protection Agency because their transmission routes are unknown, spore identification, removal, and inactivation in drinking water are technologically challenging (27), and human infections are difficult to treat (11). Considerable evidence gathered to date indicates that water is involved in the epidemiology of human microsporidiosis (10,12,14,15,25,35,38); however, this epidemiological link has not been proved conclusively (16). Identification of microsporidian spores of species known to infect humans (Encephalitozoon intestinalis, Encephalitozoon hellem, Encephalitozoon cuniculi, and Enterocytozoon bieneusi)is a challenge because microsporidians can infect a variety of nonhuman hosts and spore morphology does not provide enough information for species identification (39). This challenge is met by the multiplex fluorescence in situ hybridization (FISH) assay, which employs fluorescently labeled oligonucleotide probes targeted to species-specific sequences of 18S rRNA (19,20,22). By using various fluorochromes to label different oligonucleotide probes, spores of E. intestinalis, E. hellem, E. cuniculi, and E. bieneusi are stained red, green, orange, and yellow, respectively (19,20,22).E. hellem has been found most frequently in avian ho...

A total of 13 new Giardia isolates were established in axenic culture. All of the new isolates were obtained by excystation of Giardia cysts from the feces of patients in Dutch hospitals. These isolates were subjected to isoenzyme and DNA analysis together with isolates from Poland, Belgium, and various other parts of the world. Isoenzyme analysis revealed that nearly all of the newly established isolates exhibited unique zymodemes. Isolates obtained from individuals from Belgium and Poland, on the other hand, displayed single zymodemes. Genomic DNA libraries were constructed from isolates belonging to the latter two zymodemes; specific and common recombinant DNA clones were selected from these libraries. Differential screening revealed that the two isolates had only 80% of the clones in common. Restriction-fragment-length polymorphism analysis using three different probes together with two synthetic probes that are complementary to Giardia structural protein genes led to the separation of all isolates into two major groups; within these groups, a further division could be made by application of other techniques or probes. The results of DNA analysis and zymodeme classification were in general agreement; in the present report they are compared with the data in the literature and discussed.

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