Volume 22, Number 8—August 2016 - Emerging Infectious Disease journal - CDC

Pneumocystis carinii hominis is a ubiquitous organism that causes pneumonia in immunocompromised persons. Paired P. carinii hominis isolates from human immunodeficiency virus-infected persons who had two episodes of pneumocystosis were examined for genetic heterogeneity. Genetic variation was detected by sequence comparison of a portion of the mitochondrial ribosomal RNA gene. In 5 of 10 patients experiencing two episodes of pneumocystosis, genetically distinct isolates were associated with each episode. These included 4 of 6 patients whose second episode of pneumocystosis occurred >6 months after their initial bout. The genetic data support the hypothesis that some recurrent episodes of P. carinii hominis pneumonia are caused by reinfection rather than by reactivation of latent infection.

Changes in resident microbiota may have wide-ranging effects on human health. We investigated whether early life microbial disruption alters neurodevelopment and behavior in larval zebrafish. Conventionally colonized, axenic, and axenic larvae colonized at 1 day post fertilization (dpf) were evaluated using a standard locomotor assay. At 10 dpf, axenic zebrafish exhibited hyperactivity compared to conventionalized and conventionally colonized controls. Impairment of host colonization using antibiotics also caused hyperactivity in conventionally colonized larvae. To determine whether there is a developmental requirement for microbial colonization, axenic embryos were serially colonized on 1, 3, 6, or 9 dpf and evaluated on 10 dpf. Normal activity levels were observed in axenic larvae colonized on 1–6 dpf, but not on 9 dpf. Colonization of axenic embryos at 1 dpf with individual bacterial species Aeromonas veronii or Vibrio cholerae was sufficient to block locomotor hyperactivity at 10 dpf. Exposure to heat-killed bacteria or microbe-associated molecular patterns pam3CSK4 or Poly(I:C) was not sufficient to block hyperactivity in axenic larvae. These data show that microbial colonization during early life is required for normal neurobehavioral development and support the concept that antibiotics and other environmental chemicals may exert neurobehavioral effects via disruption of host-associated microbial communities.

Enterovirus infections are often not tracked or reported to health officials. This makes it hard to know how many people in a community are infected with these viruses at any given time. Here, we explored enterovirus in municipal wastewater to look at this issue. We show that enteroviruses are present year-round in municipal wastewater at levels of up to 800,000 genomic copies per liter. We estimate that, on average, 2.8% of the people contributing to the wastewater shed enterovirus daily. Sequence analysis of the viral capsid protein 4 gene shows that 8 enterovirus types are key drivers of seasonal trends. Populations ofEnterovirus Amembers peak in the spring, whileEnterovirus Btypes are most prevalent during the summer and fall months andEnterovirus Cmembers influence the winter months.Enterovirus Dwas observed sporadically and did not influence seasonal trends.

This article reviews the molecular genetic data pertaining to the major surface glycoprotein (MSG) gene family ofPneumocystis cariniiand its role in surface variation and compares this fungal system to antigenic variation systems in the protozoanTrypanosoma bruceiand the bacteriaBorreliaspp.