What are the modes of Hantavirus transmission?

Modes of Hantavirus Transmission

Hantavirus is primarily transmitted to humans through inhalation of infectious aerosolized saliva or excreta from infected rodents, with other potential routes including direct contact with broken skin, conjunctivae, or rodent bites. 1

Primary Transmission Routes

Rodent-to-Human Transmission

• Aerosol inhalation: The most common route of transmission occurs when humans inhale virus particles from aerosolized rodent saliva, urine, or feces. Even brief exposure (as little as 5 minutes) to areas where infected rodents are housed can result in infection 1
• Direct contact: Transmission can occur when dried materials contaminated with rodent excreta are disturbed and directly introduced into broken skin or conjunctivae 1
• Ingestion: Possible transmission through ingestion of food or water contaminated with the virus, though this route is less well-documented 1
• Rodent bites: Humans have been infected after being bitten by infected rodents 1

Exposure Settings and Activities

• Entering or cleaning previously vacant cabins or rodent-infested structures 1
• Cleaning barns and other outbuildings 1
• Disturbing rodent nests or excreta around homes or workplaces 1
• Handling mice without gloves 1
• Handling equipment or machinery that has been in storage 1
• Disturbing excreta in rodent-infested areas while hiking or camping 1

Important Characteristics of Transmission

Rodent Reservoir Dynamics

• Infected rodents remain asymptomatically infected for life and shed virus in saliva, urine, and feces 1
• Virus shedding can occur for many weeks, months, or for life, with peak shedding approximately 3-8 weeks after infection 1
• Each hantavirus is typically associated with a specific rodent host species 1
• In the southwestern United States, about one-third of trapped deer mice (Peromyscus maniculatus) had hantavirus antibodies 1

Environmental Persistence

• Limited studies show hantavirus infectivity can persist in neutral solutions for several hours at 37°C (98.6°F) and for several days at lower temperatures 1
• Virus can survive in dried cell-culture medium for up to 2 days 1
• Hantaviruses are susceptible to most disinfectants including dilute hypochlorite solutions, phenolics, detergents, and 70% alcohol 1

What Does Not Transmit Hantavirus

• Arthropod vectors: Fleas, ticks, and other ectoparasites are not known to transmit hantaviruses 1
• Person-to-person transmission: Generally not observed with most hantaviruses, with the notable exception of Andes virus 1, 2
• "Dead-end" hosts: Although antibodies have been found in predators of rodents (e.g., dogs, cats, coyotes), there is no evidence of transmission from these animals to humans 1

Special Considerations

Geographic Distribution and Virus Types

• Hantaviruses causing Hemorrhagic Fever with Renal Syndrome (HFRS) are primarily found in Europe and Asia 3
• Hantaviruses causing Hantavirus Pulmonary Syndrome (HPS) are found exclusively in the Americas 3
• The only documented person-to-person transmission has been with Andes virus in South America, particularly during an outbreak in Argentina 1, 2

Clinical Relevance

• HPS has a high mortality rate of approximately 40% across the Americas 4
• HFRS mortality varies by virus type, from <1% with Puumala virus to up to 10% with Hantaan virus 1
• Early recognition of exposure risk is critical for prompt diagnosis and management 5

Prevention Implications

• Treat all wild mice and rats in rural areas throughout the United States as potentially infected 1
• When controlling rodent populations, be aware that the same rodents may host other pathogens like Yersinia pestis (plague); control of rodents without concurrent control of fleas might increase plague risk 1
• Preventive measures should focus on reducing contact with rodents and their excreta, particularly in rural and wilderness settings 1