DESCRIPTION
Hantaviruses are hemorrhagic viruses primarily transmitted by inhalation of aerosolized rodent urine or excrement. All hantaviruses infect endothelial cells and increase vascular permeability, though they result in two main disease patterns: Hantavirus Pulmonary Syndrome (HPS) and Hemorrhagic Fever with Renal Syndrome (HFRS).
HANTAVIRUS PULMONARY SYNDROME (HPS)
HPS has higher prevalence in the Americas and is typically caused by “New World” hantaviruses, including Andes virus and Sin Nombre virus. Upon infection, viral particles infect lung endothelial cells, causing increased pulmonary vascular permeability and thrombocytopenia (decreased platelet count). Massive pulmonary hemorrhage ensues, and patients often experience severe shortness of breath, cardiovascular failure, shock, and often death even with treatment. Case fatality rate is approximately 38% [CDC]. The predominant agent of HPS in the United States is Sin Nombre virus, first identified in 1993 after an outbreak in the Four Corners Region (junction of Arizona, Colorado, Utah and New Mexico). Since its identification in 1993, 833 HPS cases have been documented by the CDC in the U.S. [CDC].
HEMORRHAGIC FEVER WITH RENAL SYNDROME (HFRS)
HFRS occurs predominantly in Europe and Asia and is caused by “Old World” hantaviruses, such as Seoul virus and Hantaan virus. Viral agents of HFRS target renal epithelial cells, and patients often experience symptoms of renal failure, such as oliguria or anuria (little or no urine production, respectively), granular appearance of urine, or even blood in the urine. Renal failure can subsequently result in fluid overload, causing edema in the legs, abdomen, and even lungs. Fever and thrombocytopenia are also common symptoms, putting the individual at risk for internal bleeding in other organs besides the kidneys. Case fatality rate varies depending on the specific hantavirus involved, but ranges from less than 1% to 15%. There are an estimated 150,000-200,000 cases of HFRS each year worldwide [Munir et al.]
TREATMENT AND PREVENTION
Treatment for both HPS or HFRS is largely supportive care to ensure patients’ airways and blood pressures are maintained [Liu et al.]. No vaccine has been licensed in the U.S. for either HPS or HFRS. However, China and Korea have utilized a vaccine against Asian agents of HFRS–called Hantavax–for decades. Hantavax has not been approved for use in the U.S. or Europe due to uncertainty of the efficacy of the vaccine; however, disease burden has decreased in countries which utilize the vaccine [Liu et al.].
The primary approach against both HPS and HFRS is prevention: limiting human exposure to rodents and rodent excrement greatly reduces the likelihood of contracting the infection. For example, the CDC recommends adequate pest control, sealing food in containers, and wetting down rodent excrement with bleach prior to sweeping it to prevent aerosolization.
Taylor is a medical student at the University of Texas Medical Branch in Galveston. She is hoping to pursue her interest in infectious diseases by specializing in Internal Medicine or Pathology.
Sources:
Centers for Disease Control and Prevention (2021). “Hantavirus.” Retrieved from https://www.cdc.gov/hantavirus/index.html.
Munir, N, Jahangeer, M, Hussain, S, et al. Hantavirus diseases pathophysiology, their diagnostic strategies and therapeutic approaches: A review. Clin Exp Pharmacol Physiol. 2021; 48: 20– 34. https://doi-org.libux.utmb.edu/10.1111/1440-1681.13403