Hantavirus 

On 8 May 2026, CDC issued a Health Advisory: 2026 Multi-country Hantavirus Cluster Linked to Cruise Ship. As a precaution, this Health Advisory summarizes CDC's recommendations for U.S. public health departments, clinical laboratories, and healthcare workers about hantavirus disease case identification, testing, and biosafety considerations in clinical laboratories. The risk of Andes virus from this outbreak to both DON personnel and the general public is extremely low. 

Overview 

Hantaviruses are a family of viruses carried by rodents worldwide.  These viruses lead to rare but potentially severe illness, with two main presentations: hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS).  Hantavirus in the Americas (“New World hantavirus”) typically causes HPS. The infection is uncommon in the United States, with only 890 cases reported between 1993 and 2023 and nearly all in Western states. Hantavirus that causes HFRS is typical in Asia and Europe (“Old World Hantavirus”). Hantavirus causing HFRS has been reported in the past among U.S. Servicemembers in South Korea and Germany after conducting field operations, occasionally causing severe illness and death. 

Hantavirus is spread to people primarily through contact with the urine, feces, or saliva of infected rodents, especially when it is stirred up into the air and inhaled. Of the forty-one known species of hantavirus, only the Andes hantavirus variant, found in South America, has been shown to be transmitted from person-to-person and those cases are uncommon, having been linked to close and prolonged contact. No human-to-human transmission has been documented for the types of hantavirus found in the U.S., Asia, and Europe.                     

Prevention of hantavirus infection centers on avoiding contact with rodent urine, droppings, saliva, and nesting materials. General rodent control measures and careful field hygiene can minimize rodent sources of infection. Particular caution should be used when cleaning after rodent infestations to minimize dust and avoid direct contact with damaged skin.  

Policy 

• AFPMB Technical Guide 41- Rodent-Borne Diseases, with Special Emphasis on Protection from Hantavirus 

• NAVMED P-5010-8 Navy Entomology and Pest Control Technology 

• NAVMED P-5010-9 Preventive Medicine for Ground Forces. 

Clinicians 

Clinical Presentation & Case Recognition:  

Hantavirus Pulmonary Syndrome 

The most severe forms of HPS are associated with the Sin Nombre virus and the Andes virus, with a case fatality rate ranging from 30-50%. Assessing patients for HPS can be difficult early in the infection because symptoms are non-specific and may resemble other infections. HPS follows a biphasic course. The febrile prodrome (2–7 days) features dizziness, severe headache, myalgias, chills, abdominal pain, vomiting, and diarrhea. Notably, upper respiratory symptoms such as sore throat and nasal congestion are infrequent, which helps distinguish it from influenza and other respiratory pathogens. Progression to the cardiopulmonary phase is abrupt, with dyspnea, tachycardia and hypotension progressing rapidly to non-cardiogenic pulmonary edema and shock. Early intensive care should be instituted if HPS is suspected, as most deaths occur within 24 hours of hospital admission.  While extracorporeal membrane oxygenation (ECMO) may be helpful, ribavirin has not been shown to be effective for HPS. Recovery is often surprisingly rapid, even after relatively severe illness. 

Hemorrhagic Fever with Renal Syndrome 

The severity of HFRS is variable depending on the specific type of hantavirus causing the infection, but in general is less life-threatening (case-fatality rate 5-15%) than HPS, and has a longer convalescence due to slow renal recovery.   

South Korea has been the most frequent source of DoW hantavirus cases, with the striped field mouse as the reservoir. South Korea reports approximately 300–600 HFRS cases per year, with the case fatality rate declining from 5–7% in the 1950s to approximately 1% from 2011–2016 due to increased clinician awareness and the availability of dialysis.

Clinically, Hantaan virus -associated HFRS in S. Korea presents with the classic triad of fever, renal insufficiency, and gastrointestinal symptoms, with hemorrhagic manifestations and a substantial proportion (approximately one-third) requiring ICU admission. The disease typically follows a five-phase course (febrile, hypotensive, oliguric, diuretic, convalescent):

• Febrile Phase (~7 days): Initial symptoms include sudden onset of fever, severe headache, back and abdominal pain and blurred vision. Occasional rash and conjunctivitis are seen. 

• Hypotensive Phase: Vascular leakage, hypotension and sometimes progression to shock. 

• Oliguric Phase (days 5-9 of illness): In 30-50% of cases, marked oliguria/anuria, rising creatin, hypertension and pulmonary edema. 

• Diuretic Phase: Initial recovery of renal function, with polyuria. Typically starts ~ day 9 of illness and lasts about a week. 

• Convalescent Phase: Progression to full renal recovery (weeks-months).  

Careful management of fluids and electrolytes is necessary, and dialysis is sometimes required to manage fluid overload. Antiviral treatment with ribavirin early in the course of illness may be helpful. 

Diagnosis: 

Initial diagnosis of HPS or HFRS can be difficult due to non-specific symptoms early in the course of illness. Additionally, there is no diagnostic test for hantavirus infection approved by the US Food and Drug Administration (FDA) in the U.S. Non-FDA approved antibody testing is available through the CDC, some state public health laboratories, and some commercial laboratories.  

Supportive laboratory clues that should raise clinical suspicion include thrombocytopenia, hemoconcentration, leukocytosis with left shift and immunoblasts, and (for HFRS) proteinuria and hematuria on urine dipstick.   

A combined testing strategy is optimal: 

• Serology (IgM/IgG ELISA) is the primary diagnostic test, with IgM being positive early in the disease and IgG appearing after the first week.  Most patients are already seropositive at presentation. 

• RT-PCR on whole blood, when available, may be particularly useful early in the course of illness, with excellent sensitivity in the first weeks of illness.  

Note: Hantavirus testing is NOT part of the Biofire Global Fever or Respiratory Panels.  

Case Reporting 

Hantavirus is a nationally notifiable disease and must also be reported within DoW.  BUMEDINST 6220.12D  requires that all cases of hantavirus be reported to Preventive Medicine authorities in the Disease Reporting System internet (DRSi). Case classification details are fully described in the Armed Forces Medical Reportable Events Guide. DCPH-A has also put together a Flowchart for Case Definition. Detailed information on reporting in DRSi can be found on NMCFHPC’s Medical Surveillance and Reporting page. Overseas locations should also coordinate with their commands to adhere to host country reporting requirements.    

Notify local Preventive Medicine and/or your cognizant  Navy Environmental and Preventive Medicine Unit (NEPMU) so that measures can be taken to mitigate the risk of local transmission.   

Public Health 

Transmission:  

Rodents are the primary reservoir hosts of hantaviruses. Each hantavirus appears to have a preferred rodent host, although the virus is variably present within the rodent’s geographic range. Hantaviruses do not cause obvious illness in the rodents. Infected rodents shed virus in saliva, urine, and feces.   

Human infection usually occurs when fresh or dried infective saliva or excreta are inhaled as aerosols, although virus may also be introduced into broken skin or through mucous membranes. It is also possible to be infected through a bite or possibly through ingestion of contaminated food or water.   

The Andes Virus is unique among hantaviruses in that it can be transmitted person-to-person through respiratory secretions, causing HPS. Spread has been limited to close contacts and healthcare workers, suggesting generally low transmissibility. 

There is often seasonal variation in rodent prevalence (e.g. autumn in southwestern Korea), and environmental conditions may trigger wild rodent population explosions that can result in increased exposure of people to rodents and their excreta. Public health personnel should be cognizant of potentially increased risk of hantavirus when there is unusually high rodent activity in their AOR.  

Incubation Period:  

Symptoms typically develop 2-6 weeks (median of 14 to 17 days) after exposure, although incubation periods of up to 8 weeks have been reported.  

Case Management:  

HFRS often occurs as part of an outbreak (e.g. multiple members of a unit who had the same environmental exposure), and in the event of a military case a detailed history of potential exposures in the previous 6 weeks must be collected to facilitate identification of additional personnel who may have been exposed. Individuals with shared exposure history should monitor for symptoms for 45 days after departing an impacted area or last known exposure. Testing of asymptomatic personnel is not recommended, but line leadership and local medical personnel should be alerted to the potential for hantavirus to ensure rapid diagnosis of exposed personnel.  

Control Measures:  

Vaccines: There is no human vaccine for hantaviruses licensed by the FDA in the United States, although there are vaccines in development.  

Patient Isolation: With the exception of Andes Virus in South America, hantavirus is not transmitted person-to-person and isolation of patients is not required. For patients with known or suspected Andes virus infection, CDC recommends the following for healthcare settings: patient placement in an AIIR and the use of a gown, gloves, eye protection, and N95 or higher-level respirator when entering the patient's room (see “Andes Virus” in CDC’s online Appendix A: Type and Duration of Precautions Recommended for Selected Infections and Conditions). 

Exposure control: The most effective prevention strategy is avoiding rodent exposure. Risk is highest when rodent droppings or urine are aerosolized in enclosed spaces such as buildings, bunkers or warehouses, especially when infrequently used. Areas with evidence of rodent infestations should be thoroughly disinfected and cleaned to reduce the likelihood of exposure to hantavirus-infected materials. Cleanup procedures should be performed in a manner that limits the potential for aerosolization of rodent-contaminated material (e.g., wet mopping instead of sweeping). Anyone involved in cleaning rodent-infested buildings or handling dead rodents should use proper procedures, including using approved disinfectants and protective clothing. Details for safe rodent disposal and cleanup procedures may be found in AFPMB Technical Guide 41- Rodent-Borne Diseases, with Special Emphasis on Protection from Hantavirus. 

Environmental Controls: In endemic areas, rodent-proof buildings and strictly enforce sanitation to minimize rodent food sources. In the field, optimize camp hygiene and implement rodent control measures. Commanders and Preventive Medicine personnel should ensure compliance with field sanitation standards in accordance with NAVMED P-5010-9 Preventive Medicine for Ground Forces. 

Education and awareness: In areas with significant hantavirus risk, FHP briefs should include information about the importance of rodent control and the risks from inhalation of rodent excreta. Information about safe cleanup of rodent infestations should be made readily available.  

Web Resources 

CDC Main Hantavirus Site 

CDC Andes Virus Fact Sheet 

DHA Hantavirus Case Investigation Worksheet 

Epi and Selected Publications 

Pon E, McKee KT, Diniega BM, Berrill B, Corwin A, Ksiazek TG. Outbreak of Hemorrhagic Fever with Renal Syndrome Among U.S. Marines in Korea Am J Trop Med Hyg. 1990  

Clement  J, Underwood  P, Ward  D, Pilaski  J, LeDuc  J. Hantavirus outbreak during military manoeuvres in Germany. Lancet. Vol347; Iss 8997; p336. 1996 https://doi.org/10.1016/S0140-6736(96)90519-X. 

Clement J, Heyman P, McKenna P, Colson P, Avsic-Zupanc T. The Hantaviruses of Europe: from the Bedside to the Bench. Emerg Infect Dis. 1997;3(2):205-211. https://dx.doi.org/10.3201/eid0302.970218, https://wwwnc.cdc.gov/eid/article/3/2/97-0218_article#r5. 

McCormic ZD, Balihe MN, Havas KA, Baty SA. Puumala hantavirus outbreak among U.S. military health care beneficiaries, Stuttgart, Germany--2012. MSMR. 2013 Dec;20(12):12-5. PMID: 24428538. 

Mustonen J, Henttonen H, Vaheri A. Hantavirus Infections among Military Forces. Mil Med. 2024 Feb 27;189(3-4):551-555. doi: 10.1093/milmed/usad261. PMID: 37428512; PMCID: PMC10898924. 

Rouabhia R, Dinh DT, Kua SC, Washington MA. Lessons Learned From the U.S. Military Experience With Hantavirus During the Korean War. Mil Med. 2023 Aug 29;188(9-10):3205-3209. doi: 10.1093/milmed/usac255. PMID: 36099403. 

J. W. Le Duc: Hantaviral Diseases. Control of Communicable Diseases Manual.  https://doi.org/10.2105/CCDM.2745.074