Strongyloides Hyperinfection Syndrome: A Curious Case of Asthma Worsened by Systemic Corticosteroids.

BACKGROUND Strongyloidiasis, caused by infection with Strongyloides stercoralis parasitic nematodes, is most prevalent in tropical regions of the world, such as South America, Southeast Asia, and sub-Saharan Africa, but its incidence has increased in nonendemic areas of the United States due to immigration. The majority of patients remain asymptomatic or have only mild gastrointestinal, respiratory, or dermatologic symptoms. Unrecognized strongyloidiasis can progress to Strongyloides hyperinfection syndrome, a highly fatal complication that can occur in response to immunosuppressive therapy. This rare complication is easily misdiagnosed because of its similar presentation to asthma or exacerbation of chronic obstructive pulmonary disease. CASE REPORT We report a case of worsening therapeutic response to systemic corticosteroids in an elderly Colombian man who presented with symptoms of acute exacerbation of asthma. His history was positive for residence in a region endemic to S. stercoralis, and he had undergone multiple hospitalizations over the past few years for pulmonary, gastrointestinal, and dermatologic complaints. Laboratory results were significant for increased eosinophilia, and chest radiography showed blunting of the left costophrenic angle. The patient was found to have S. stercoralis hyperinfection after parasitic larvae were detected in a bronchoalveolar lavage sample. Symptoms improved after a course of ivermectin, and the patient was subsequently discharged. CONCLUSIONS This unusual presentation of Strongyloides hyperinfection syndrome showcases the dangers of corticosteroid therapy in individuals with undiagnosed Strongyloides infection who present with a presumed diagnosis of asthma exacerbation. Clinicians should maintain a high level of suspicion when treating patients from S. stercoralis endemic regions presenting with pulmonary, gastrointestinal, and/or dermatologic symptoms. Ivermectin is the current standard of care for both asymptomatic and complicated strongyloidiasis.

The B73 maize genome: complexity, diversity, and dynamics.

We report an improved draft nucleotide sequence of the 2.3-gigabase genome of maize, an important crop plant and model for biological research. Over 32,000 genes were predicted, of which 99.8% were placed on reference chromosomes. Nearly 85% of the genome is composed of hundreds of families of transposable elements, dispersed nonuniformly across the genome. These were responsible for the capture and amplification of numerous gene fragments and affect the composition, sizes, and positions of centromeres. We also report on the correlation of methylation-poor regions with Mu transposon insertions and recombination, and copy number variants with insertions and/or deletions, as well as how uneven gene losses between duplicated regions were involved in returning an ancient allotetraploid to a genetically diploid state. These analyses inform and set the stage for further investigations to improve our understanding of the domestication and agricultural improvements of maize.