What are the management and treatment options for an adult with no significant past medical history (PMH) who has been exposed to mouse droppings and is at risk for hantavirus infection, particularly hantavirus pulmonary syndrome (HPS)?

Management of Hantavirus Exposure and Infection

For an adult exposed to mouse droppings at risk for hantavirus pulmonary syndrome, immediate supportive care with aggressive hemodynamic monitoring is the cornerstone of management, as there is no FDA-approved antiviral therapy or vaccine available in the United States, and mortality exceeds 50% once cardiopulmonary syndrome develops. 1, 2

Immediate Clinical Assessment and Monitoring

If the patient is asymptomatic after exposure, focus on education about warning signs and ensure close monitoring for 45 days post-exposure, as this represents the incubation period. 3

• Monitor for febrile or respiratory illness development for 45 days after last rodent exposure 3
• Educate the patient to seek immediate care if they develop fever, myalgias, or respiratory symptoms 2, 4
• The absolute risk of infection remains low despite exposure, with only 20-50 cases confirmed annually in the United States 1

Recognition of Hantavirus Pulmonary Syndrome

Early recognition is critical because HPS progresses rapidly through three distinct phases: prodromal (flu-like symptoms), cardiopulmonary (acute respiratory failure), and convalescent. 4

Prodromal Phase (First 3-5 days):

• Fever, myalgias, headache, nausea, vomiting, and gastrointestinal pain 2, 4
• Common pitfall: HPS is frequently misdiagnosed as gastroenteritis or influenza during this phase 2
• Thrombocytopenia and hemoconcentration are characteristic laboratory findings even in the prodromal phase 5

Cardiopulmonary Phase (Days 4-10):

• Rapid onset of noncardiogenic pulmonary edema, pleural effusion, and acute respiratory distress syndrome 2, 4
• Hypotension, shock, and severe hypoxemia develop rapidly 1, 5
• Common pitfall: Often misdiagnosed as pneumonia or idiopathic ARDS 2

Treatment Protocol

There is no FDA-approved antiviral therapy for HPS; management is entirely supportive with aggressive intensive care monitoring. 1, 4

Immediate Stabilization:

• Secure the airway immediately if the patient demonstrates CNS depression, loss of protective reflexes, or respiratory compromise 3
• Establish hemodynamic support and correct critical vital signs before pursuing other interventions 3
• Obtain IV access and prepare for rapid clinical deterioration 3

Intensive Care Management:

• Provide oxygen and cardiovascular support with inotropic and vasopressor drugs for hypotension 4
• Anticipate need for mechanical ventilation given the rapid progression to respiratory failure 2, 4
• Monitor for metabolic derangements requiring immediate correction 3
• Perform EEG monitoring for non-convulsive seizures in patients with altered mental status 3
• Administer benzodiazepines for seizures or agitation, particularly if intracranial hemorrhage develops 3

Experimental Therapy:

• Ribavirin has been investigated but remains experimental with no proven efficacy for HPS 2
• Do not delay supportive care while considering experimental therapies 2

Environmental Decontamination and Prevention

Proper cleanup of rodent-contaminated areas is essential to prevent further exposure, as transmission occurs through inhalation of aerosolized virus from dried rodent excreta. 1

Before Cleanup:

• Ventilate closed buildings for at least 30 minutes before entering areas with potential rodent contamination 3
• Contact local or state public health agencies for guidance before cleanup if heavy infestation or confirmed hantavirus case 3

During Cleanup:

• Wear rubber, latex, vinyl, or nitrile gloves during all cleanup activities 3
• Spray all rodent droppings, urine, nests, and dead rodents with disinfectant or 1:10 bleach solution until thoroughly soaked before handling 3
• Critical pitfall: Never vacuum or sweep contaminated areas until after disinfection, as this aerosolizes infectious particles 3
• For heavy rodent infestations or confirmed hantavirus cases, workers must wear coveralls, rubber boots, protective goggles, and appropriate respiratory protection 3

Disposal:

• Double-bag all contaminated materials in plastic bags 3
• Dispose by burying 2-3 feet deep, burning, or placing in regularly emptied covered trash 3

Key Clinical Pearls

• Hantaviruses are lipid-enveloped and susceptible to most disinfectants including dilute bleach solutions, detergents, and 70% alcohol 1
• The virus survives less than 1 week indoors and only hours when exposed to sunlight outdoors 1
• Person-to-person transmission has not been documented in the United States (only with Andes virus in South America) 1
• Transmission occurs through inhalation of aerosolized virus, direct introduction into broken skin or conjunctivae, or rodent bites 1
• The deer mouse (Peromyscus maniculatus) is the primary reservoir in North America 1, 2

When to Escalate Care

• Any patient with rodent exposure who develops fever and respiratory symptoms requires immediate hospitalization and intensive care consultation 2, 4
• Early ICU admission is critical given the rapid progression from prodromal symptoms to respiratory failure 4
• Mortality rates exceed 50% once cardiopulmonary syndrome develops, emphasizing the importance of maximal supportive care 1, 2