Hantavirus

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Background

  • Infection by the Sin Nombre virus can range from a nonspecific viral syndrome to the Hanta Pulmonary Syndrome (HPS), which is a severe respiratory manifestation with a high mortality rate
  • Virus is transmitted by rodent urine, droppings, and saliva
  • North American resevoir includes deer mouse, white footed mouse, and cotton rat
  • Most cases of exposure US have occurred in southwest states

Clinical Features

Hantavirus Pulmonary Syndrome (HPS)

  • Develops several days later, including shortness of breath and cough which rapidly progresses to noncardiogenic pulmonary edema and respiratory failure over 24-48 hours
  • Hemodynamical instability may ensue in the late phase
  • Symptoms that make HPS less likely includes conjunctival injection, petechiae, or rashes

Differential Diagnosis

  • Wegener's granulomatosis
  • Goodpasture's syndrome

Lower Respiratory Zoonotic Infections

Evaluation

  • Serologic test using ELISA assays are the gold standard used by the CDC
  • Most patients have antiviral IgM when symptoms are present, IgG may also be positive later on

Labs and Imaging

  • Earliest lab abnormalities includes a decline in platelet count
  • May also see an elevation in LDH, LFTs, and lactate later
  • In HPS, the chest x-ray shows diffuse bilateral interstitial edema that may resemble ARDS
  • Decrease in albumin along with increases in H/H marks is a markeer of capillary leak in HPS
  • The diagnostic triad in HPS includes thrombocytopenia, left shifted granulocytes, and immunoblast >10% of total lympoid series

LA County Guidelines (for Yosemite outbreak)

Physicians with Patients Presenting with Concerns or Symptoms of Hantavirus Pulmonary Syndrome (HPS) after Visit to Yosemite National Park, June through August 2012.

  1. If a patient presents with concerns or non-specific symptoms well after 6 weeks from their stay in Yosemite, the patient most likely does not have hantavirus infection and testing for hantavirus infection is not indicated.
  2. If a patient presents with non-specific symptoms within 6 weeks of their stay in Yosemite and hantavirus infection is not suspected, the patient should be followed as clinically indicated, but testing for hantavirus infection is not indicated.
  3. If a patient presents with fever and mild symptoms suspicious for early hantavirus infection within 6 weeks of their stay in Yosemite, then a complete blood count (CBC) and chemistry panel should be done at baseline and hantavirus serology should be requested.
  4. If a patient presents with fever, shortness of breath, and other symptoms suggestive of HPS within 6 weeks of their stay in Yosemite, or if the patient in #3 above progresses to having symptoms and laboratory results suggestive of HPS, the patient should be transferred to a hospital emergency department for full evaluation.
  5. In California, hantavirus infections are reportable. Suspect cases in LA County should be reported to Acute Communicable Disease Control immediately so that we may assist with diagnostic testing.

Call 213-240-7941 (business hours) or 213-974-1234 (after hours) to speak to the duty physician.

Management

  • Supportive care is the main form of treatment
  • Aggressive respiratory support including early intubation and mechanical ventilation for HPS
  • Hemodynamic support with early vasopressor administration
  • Consider ECMO for refractory cases

Disposition

See Also

References

These are abbreviated public health recommendations. Please see the full state guidance document at [1]