Epidemiology and risk factors Toxoplasma gondii is a protozoan parasite in the phylum Apicomplexa. It infects humans and almost all warm-blooded animals, including mammals and birds. Transmission of T. gondii…

Histoplasmosis, blastomycosis, and coccidioidomycosis are the most common endemic mycoses in North America. Their geographic distribution encompasses close to two-thirds of the United States and parts of Canada, Mexico, Central…

The vast majority of invasive yeast infections in organ transplant recipients and patients with malignancy are caused by Candida species. However, a variety of other yeasts are important opportunistic pathogens…

The Candida genus represents a group of more than 200 species present in both human flora and the environment. Of these, approximately 20 have been implicated in human disease. Typically,…

Although invasive aspergillosis is the most common invasive mold disease (IMD), mucormycosis and other non- Aspergillus opportunistic mold infections are increasingly associated with significant morbidity and mortality among highly immunocompromised…

Aspergillus is a ubiquitous organism with an ecological niche in the soil. Most disease is primarily caused by A. fumigatus , A. flavus , A. niger , A. terreus ,…

Polyomavirus (PyV) infections were first described in mice in 1952 as a cause of tumors in newborn animals. Since then, PyVs have been found in virtually all vertebrates, including primates,…

Adenoviruses In the past few decades, significant progress has been made in understanding the epidemiology of adenovirus infections and developing preventative and therapeutic strategies. However, adenovirus infections remain a clinical…

Epidemiology and risk factors The seasonality of respiratory virus infections among immunocompromised children is similar to that in the community ( Fig. 21.1 ). Respiratory syncytial virus (RSV) typically circulates…

Over the past several decades, three novel human herpesviruses (HHVs) have been identified and designated HHV-6, HHV-7, and HHV-8. HHV-6 has since been designated as two distinct species, HHV-6A and…