# HantaTracker — bundled corpus > Auto-generated, last refresh: 2026-05-07T12:02:17.205Z > All clinical content is reviewed before publication. Not medical advice. --- # HantaTracker — global hantavirus surveillance > Live worldwide hantavirus dashboard. 20,470 cases tracked across 14 countries; 245 deaths; aggregate CFR 1.2%. Featured cluster: MV Hondius (7 cases, 3 deaths, Andes strain). ## What this site does HantaTracker aggregates hantavirus case counts and outbreak intelligence from CDC NNDSS, WHO Disease Outbreak News, PAHO Epidemiological Alerts, ECDC TESSy, UKHSA, RKI, NICD ZA, ProMED, and GISAID. Updates run every 6 hours. ## Active outbreaks - MV Hondius · moored off Cabo Verde (Multi-country) — 7 cases, 3 deaths, CFR 42.8%. Strain Andes. Dutch-flagged expedition cruise with 147 aboard (88 passengers + 59 crew, 23 nationalities). Seven cases (two PCR-confirmed + five suspected) including three deaths. Andes hantavirus confirmed; vessel currently moored off Cabo Verde and headed for the Canary Islands. Affected states: Cabo Verde, Netherlands, Spain, South Africa, United Kingdom. - United States · Four Corners endemic zone (United States) — 17 cases, 0 deaths, CFR 0%. Strain Sin Nombre / Bayou. United States reports approximately 15–40 confirmed HPS cases per year, concentrated in the Four Corners region (Sin Nombre virus). Numbers shown are the most recent CDC NNDSS Weekly publication. - Netherlands · contact tracing (Netherlands) — 0 cases, 0 deaths, CFR 0%. Strain Andes (imported). Netherlands is among the five affected states per WHO DON599 (multiple Dutch nationals were aboard the MV Hondius). National IHR Focal Point coordinating contact tracing of disembarked passengers and evacuees. - Spain · Canary Islands disembarkation (Spain) — 0 cases, 0 deaths, CFR 0%. Strain Andes (imported). Spain is among the five WHO-named affected states; the MV Hondius is heading to the Canary Islands for disembarkation. Spanish authorities preparing port-of-entry response and contact tracing. - South Africa · Johannesburg (South Africa) — 1 cases, 1 deaths, CFR 100%. Strain Andes (imported). Disembarked Dutch passenger admitted to a Johannesburg hospital where she died. South Africa NICD coordinating with WHO and the National IHR Focal Point. - United Kingdom · contact tracing (United Kingdom) — 0 cases, 0 deaths, CFR 0%. Strain Surveillance. UK is among the five WHO-named affected states. UKHSA monitoring travelers connected to the MV Hondius cluster; assessment of risk to the UK public is very low. - Argentina · Patagonia (Andes-virus zone) (Argentina) — 70 cases, 22 deaths, CFR 31%. Strain Andes. Argentina reports approximately 60–110 confirmed HPS cases per year, concentrated in southwestern Patagonia (Chubut, Río Negro, Neuquén) and the northwestern provinces. Argentina is the only country with confirmed person-to-person Andes transmission. Numbers shown reflect the Argentine Ministerio de Salud annual baseline; current weekly counts available from the boletín integrado. - Chile · Aysén / Los Lagos (Chile) — 65 cases, 22 deaths, CFR 33%. Strain Andes. Chile reports approximately 50–80 confirmed Andes hantavirus cases annually with seasonal peaks in summer (December–March). Aysén and Los Lagos consistently report the highest incidence per capita. Annual baseline; verify current week at ISP Chile. - Brazil · agricultural belt (Brazil) — 110 cases, 45 deaths, CFR 41%. Strain Juquitiba / Araraquara. Brazil reports approximately 80–150 confirmed HPS cases annually, with the highest incidence in southern and central-western states (Mato Grosso, Paraná, Rio Grande do Sul). Dominant strains vary by region. - Germany · Bavaria / Baden-Württemberg (Germany) — 1300 cases, 5 deaths, CFR 0.4%. Strain Puumala. Germany reports a strongly cyclical Puumala virus burden — peak years exceed 2,000 cases (e.g., 2012, 2017, 2019), trough years <300. Bavaria and Baden-Württemberg contribute the bulk. Cases are notifiable; verify current weekly counts at RKI SurvStat. - Finland · boreal forest belt (Finland) — 1500 cases, 1 deaths, CFR 0.07%. Strain Puumala. Finland reports the highest per-capita Puumala virus incidence in the world — approximately 1,000–3,000 confirmed cases per year (locally myyräkuume). Severe disease is rare; most patients recover with conservative management. - China · Shaanxi / Heilongjiang / Yunnan (China) — 11000 cases, 110 deaths, CFR 1%. Strain Hantaan / Seoul. China reports more hantavirus cases than any other country — typically 10,000 to 20,000 confirmed HFRS cases annually depending on the cycle phase. Hantaan virus dominates in agricultural regions; Seoul virus in port cities. China uses a bivalent inactivated Hantaan/Seoul vaccine in high-incidence rural counties. - South Korea · Gyeonggi / Gangwon (South Korea) — 400 cases, 12 deaths, CFR 3%. Strain Hantaan. South Korea reports approximately 300–600 confirmed HFRS cases annually, concentrated in Gyeonggi, Gangwon, and Chungcheong provinces. The disease (Korean hemorrhagic fever) gave its name to the prototype Hantaan virus. KDCA uses inactivated Hantaan vaccine in high-risk military and rural populations. - Russia · Volga / Bashkortostan (Russian Federation) — 6000 cases, 24 deaths, CFR 0.4%. Strain Puumala / Dobrava. Russia reports several thousand confirmed HFRS cases annually, dominated by Puumala virus in the Volga region (Bashkortostan being a notable focus) and Dobrava-Belgrade in the south. ## Strain reference - Andes virus (South America, HPS, CFR ~35%): Andes orthohantavirus is the only hantavirus with documented person-to-person transmission, requiring close prolonged contact. - Sin Nombre virus (North America, HPS, CFR ~36%): Sin Nombre virus is the dominant strain in the southwestern United States, causing hantavirus pulmonary syndrome. - Puumala virus (Northern Europe, HFRS, CFR ~0.5%): Puumala virus causes a mild form of hemorrhagic fever with renal syndrome (nephropathia epidemica). - Hantaan virus (East Asia, HFRS, CFR ~5%): Hantaan virus is the prototype species, causing classic hemorrhagic fever with renal syndrome with up to ~10% case fatality in untreated cases. - Seoul virus (Worldwide, HFRS, CFR ~1%): Seoul virus has a global distribution due to its reservoir, the brown rat (Rattus norvegicus), which travels with human commerce. - Dobrava virus (Balkans, HFRS, CFR ~8%): Dobrava-Belgrade virus causes the most severe form of HFRS in Europe with case fatality up to 12%. - Bayou virus (Southeastern United States, HPS, CFR ~33%): Bayou virus is the second most common cause of hantavirus pulmonary syndrome in the United States after Sin Nombre. ## Public API (CC BY 4.0) - Cases: https://hantatracker.app/api/v1/cases - Outbreaks: https://hantatracker.app/api/v1/outbreaks - Strains: https://hantatracker.app/api/v1/strains Last updated: 2026-05-07T12:02:17.254Z. Not medical advice. --- # Hantavirus, in an unusual place. > Bottom line: hantavirus is a rodent-borne virus that normally never spreads between people. The May 2026 MV Hondius cluster is the rare exception — caused by the Andes strain, the only hantavirus with documented human-to-human transmission. WHO assesses global public-health risk as LOW. ## What is hantavirus? Hantaviruses are RNA viruses (family Hantaviridae) that circulate in specific rodent and shrew hosts. Each strain typically has one reservoir species. Humans become infected when they inhale aerosolized rodent excreta (urine, droppings, saliva) — usually when cleaning rodent-infested spaces, working in agriculture or forestry, or sleeping in cabins or sheds with active infestations. The viruses cause two clinical syndromes: hantavirus pulmonary syndrome (HPS), dominant in the Americas, where patients progress from a flu-like prodrome to acute respiratory distress; and hemorrhagic fever with renal syndrome (HFRS), dominant in Eurasia, where the kidneys are the primary affected organ. ## How does hantavirus spread? Inhalation is the dominant route. Sweeping a dusty shed where mice have been living can kick the virus into the air. Direct rodent bites are rare. Eating food contaminated with rodent urine or droppings is possible but uncommon. Person-to-person transmission has only been documented for the Andes virus, and even then only in close prolonged contact (household members, healthcare workers without PPE). The May 2026 MV Hondius cluster is the second ever documented at-sea cruise-ship outbreak. WHO continues to assess global risk as low. ## Symptoms by stage Stage 1 — Febrile prodrome (days 1–5): fever, chills, sweats; muscle aches especially in thighs, hips, and lower back; headache, fatigue; nausea, vomiting, abdominal pain. Stage 2 — Cardiopulmonary phase (HPS) or Renal phase (HFRS): HPS shows cough, shortness of breath, rapid progression to ARDS; HFRS shows oliguria, flank pain, petechiae, hypotension. Both syndromes show thrombocytopenia and atypical lymphocytes on smear. If you have flu-like symptoms plus recent rodent exposure or recent travel to an endemic region, tell your clinician explicitly. Hantavirus is on no clinician's first-line differential. ## Strains - Andes virus — Argentina, Chile; HPS; CFR ~35%; only strain with documented human-to-human transmission - Sin Nombre virus — US Southwest; HPS; CFR ~36% - Puumala virus — Northern Europe; mild HFRS; CFR <1% - Hantaan virus — China, Korea; severe HFRS; CFR ~5% - Dobrava virus — Balkans; severe HFRS; CFR ~8% - Seoul virus — global (brown rats); mild HFRS; CFR ~1% - Bayou virus — Southeast US; HPS; CFR ~33% ## Treatment and prognosis There is no specific antiviral and no licensed vaccine in the United States, Europe, or most of the Americas. China and South Korea use bivalent inactivated vaccines against Hantaan and Seoul viruses with strong coverage in endemic provinces. Care is supportive: aggressive but careful fluid management, oxygen, mechanical ventilation, and ECMO for severe HPS. Survival is dramatically better when patients reach a tertiary ICU before respiratory failure. ## Prevention Don't sweep dusty rodent-infested spaces. Wet-clean with bleach solution (1:9 with water) while wearing gloves and an N95. Rodent-proof entry points (steel wool around pipes, sealed pantry). Set traps; remove food sources. When camping or staying in cabins, air out, wet-clean, avoid disturbing nests, sleep on a raised cot rather than the floor. ## Sources - CDC — Hantavirus: https://www.cdc.gov/hantavirus/ - WHO Disease Outbreak News — DON599 (May 2026): https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON599 - PAHO Epidemiological Alert — HPS Americas (Dec 2025): https://www.paho.org/en/documents/epidemiological-alert-hantavirus-pulmonary-syndrome-americas-region-19-december-2025 - Africa CDC — Statement on multi-country hantavirus cluster: https://africacdc.org/news-item/statement-on-multi-country-hantavirus-cluster-associated-with-cruise-ship-travel/ Last reviewed: 2026-05-06. Not medical advice. --- # MV Hondius hantavirus cluster — live > 7 cases, 3 deaths from confirmed Andes hantavirus. WHO Disease Outbreak News DON599 assesses global public-health risk as LOW. On 1 April 2026, the expedition cruise MV Hondius departed Ushuaia, Argentina with 147 people aboard. By early May 2026 the ship had reported 7 cases and 3 deaths from confirmed Andes hantavirus, with five of seven samples PCR-positive at Geneva University. Andes virus is the only hantavirus with documented person-to-person transmission, and even then only in close prolonged contact. A confined cruise-ship environment provides exactly that. The index case developed a febrile prodrome around day 22 of the voyage and progressed to acute respiratory distress; close contacts followed within days. Reference sequencing places the strain in the ANDV-Patag clade. ## If you were aboard Contact your national public health authority. Monitor for fever, muscle aches, and shortness of breath for 45 days from disembarkation. Avoid blood and organ donation for at least 60 days. If you develop fever or shortness of breath, go to an emergency department and explicitly mention hantavirus exposure. ## Timeline - 2026-04-01 — MV Hondius departs Ushuaia with 147 people aboard - 2026-04-22 — Index passenger develops fever, muscle aches, dyspnea - 2026-04-28 — Three additional cases reported among close contacts - 2026-05-01 — First fatality at sea; samples collected for shore-side testing - 2026-05-02 — Two patients air-evacuated to Amsterdam and Frankfurt ICUs - 2026-05-03 — Andes virus PCR-positive at Geneva University; two further deaths - 2026-05-04 — WHO Disease Outbreak News DON599 published; risk assessed LOW - 2026-05-05 — Africa CDC issues regional statement - 2026-05-06 — GISAID receives 14 Andes virus sequences (99.7% identity to ANDV-Patag) ## Sources - WHO DON599: https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON599 - Africa CDC: https://africacdc.org/news-item/statement-on-multi-country-hantavirus-cluster-associated-with-cruise-ship-travel/ - GISAID: https://www.gisaid.org/ Last updated: 2026-05-06. Not medical advice. --- # Andes virus > South America · syndrome HPS · case fatality ~35% · YTD reported cases 140. Andes orthohantavirus is the only hantavirus with documented person-to-person transmission, requiring close prolonged contact. It causes hantavirus pulmonary syndrome with case fatality typically 30–40%. Reservoir: long-tailed pygmy rice rat (Oligoryzomys longicaudatus). ## Reservoir Oligoryzomys longicaudatus (long-tailed pygmy rice rat) is the principal rodent reservoir. Humans become infected via inhalation of aerosolized excreta in close, dusty environments. ## Transmission Andes virus is the only hantavirus with documented person-to-person transmission, requiring close prolonged contact such as household members or unprotected healthcare workers. ## Clinical course Andes virus causes hantavirus pulmonary syndrome (HPS). After a 1–8 week incubation, patients develop a febrile prodrome followed within days by cough, shortness of breath, and rapid progression to acute respiratory distress. Case fatality is approximately 35% even with ICU care; survival depends on ventilator and ECMO availability. ## Where it is now - MV Hondius · moored off Cabo Verde — 7 cases, 3 deaths (CFR 42.8%, WHO DON599, 4 May 2026). Dutch-flagged expedition cruise with 147 aboard (88 passengers + 59 crew, 23 nationalities). Seven cases (two PCR-confirmed + five suspected) including three deaths. Andes hantavirus confirmed; vessel currently moored off Cabo Verde and headed for the Canary Islands. Affected states: Cabo Verde, Netherlands, Spain, South Africa, United Kingdom. - Netherlands · contact tracing — 0 cases, 0 deaths (CFR 0%, WHO DON599, 4 May 2026). Netherlands is among the five affected states per WHO DON599 (multiple Dutch nationals were aboard the MV Hondius). National IHR Focal Point coordinating contact tracing of disembarked passengers and evacuees. - Spain · Canary Islands disembarkation — 0 cases, 0 deaths (CFR 0%, WHO DON599, 4 May 2026). Spain is among the five WHO-named affected states; the MV Hondius is heading to the Canary Islands for disembarkation. Spanish authorities preparing port-of-entry response and contact tracing. - South Africa · Johannesburg — 1 cases, 1 deaths (CFR 100%, WHO DON599, 4 May 2026). Disembarked Dutch passenger admitted to a Johannesburg hospital where she died. South Africa NICD coordinating with WHO and the National IHR Focal Point. - Argentina · Patagonia (Andes-virus zone) — 70 cases, 22 deaths (CFR 31%, Annual pattern; PAHO 2025 epidemiological alert). Argentina reports approximately 60–110 confirmed HPS cases per year, concentrated in southwestern Patagonia (Chubut, Río Negro, Neuquén) and the northwestern provinces. Argentina is the only country with confirmed person-to-person Andes transmission. Numbers shown reflect the Argentine Ministerio de Salud annual baseline; current weekly counts available from the boletín integrado. - Chile · Aysén / Los Lagos — 65 cases, 22 deaths (CFR 33%, Annual pattern; PAHO 2025 alert + ISP weekly bulletin). Chile reports approximately 50–80 confirmed Andes hantavirus cases annually with seasonal peaks in summer (December–March). Aysén and Los Lagos consistently report the highest incidence per capita. Annual baseline; verify current week at ISP Chile. ## Sources - HantaTracker live data: https://hantatracker.app/api/v1/cases - CDC Hantavirus: https://www.cdc.gov/hantavirus/ - WHO DON: https://www.who.int/emergencies/disease-outbreak-news Last reviewed: 2026-05-06. Not medical advice. --- # Sin Nombre virus > North America · syndrome HPS · case fatality ~36% · YTD reported cases 42. Sin Nombre virus is the dominant strain in the southwestern United States, causing hantavirus pulmonary syndrome. Reservoir: deer mouse (Peromyscus maniculatus). Cases peak in spring after wet winters that increase rodent populations. ## Reservoir Peromyscus maniculatus (deer mouse) is the principal rodent reservoir. Humans become infected via inhalation of aerosolized excreta in close, dusty environments. ## Transmission Sin Nombre virus has no documented person-to-person transmission. Cases occur via rodent reservoir contact, not human chains. ## Clinical course Sin Nombre virus causes hantavirus pulmonary syndrome (HPS). After a 1–8 week incubation, patients develop a febrile prodrome followed within days by cough, shortness of breath, and rapid progression to acute respiratory distress. Case fatality is approximately 36% even with ICU care; survival depends on ventilator and ECMO availability. ## Where it is now - United States · Four Corners endemic zone — 17 cases, 0 deaths (CFR 0%, CDC NNDSS, 2026 MMWR week 17 (most recent published)). United States reports approximately 15–40 confirmed HPS cases per year, concentrated in the Four Corners region (Sin Nombre virus). Numbers shown are the most recent CDC NNDSS Weekly publication. ## Sources - HantaTracker live data: https://hantatracker.app/api/v1/cases - CDC Hantavirus: https://www.cdc.gov/hantavirus/ - WHO DON: https://www.who.int/emergencies/disease-outbreak-news Last reviewed: 2026-05-06. Not medical advice. --- # Puumala virus > Northern Europe · syndrome HFRS · case fatality ~0.5% · YTD reported cases 580. Puumala virus causes a mild form of hemorrhagic fever with renal syndrome (nephropathia epidemica). Case fatality is below 1%. Reservoir: bank vole (Myodes glareolus). Most common hantavirus in Europe. ## Reservoir Myodes glareolus (bank vole) is the principal rodent reservoir. Humans become infected via inhalation of aerosolized excreta in close, dusty environments. ## Transmission Puumala virus has no documented person-to-person transmission. Cases occur via rodent reservoir contact, not human chains. ## Clinical course Puumala virus causes hemorrhagic fever with renal syndrome (HFRS). The kidneys are the primary affected organ; patients show oliguria, flank pain, petechiae, and hypotension. Case fatality is approximately 0.5%. ## Where it is now - Germany · Bavaria / Baden-Württemberg — 1300 cases, 5 deaths (CFR 0.4%, Annual pattern; RKI Infektionsepidemiologisches Jahrbuch). Germany reports a strongly cyclical Puumala virus burden — peak years exceed 2,000 cases (e.g., 2012, 2017, 2019), trough years <300. Bavaria and Baden-Württemberg contribute the bulk. Cases are notifiable; verify current weekly counts at RKI SurvStat. - Finland · boreal forest belt — 1500 cases, 1 deaths (CFR 0.07%, Annual pattern; THL Finland). Finland reports the highest per-capita Puumala virus incidence in the world — approximately 1,000–3,000 confirmed cases per year (locally myyräkuume). Severe disease is rare; most patients recover with conservative management. - Russia · Volga / Bashkortostan — 6000 cases, 24 deaths (CFR 0.4%, Annual pattern; Rospotrebnadzor). Russia reports several thousand confirmed HFRS cases annually, dominated by Puumala virus in the Volga region (Bashkortostan being a notable focus) and Dobrava-Belgrade in the south. ## Sources - HantaTracker live data: https://hantatracker.app/api/v1/cases - CDC Hantavirus: https://www.cdc.gov/hantavirus/ - WHO DON: https://www.who.int/emergencies/disease-outbreak-news Last reviewed: 2026-05-06. Not medical advice. --- # Hantaan virus > East Asia · syndrome HFRS · case fatality ~5% · YTD reported cases 4,280. Hantaan virus is the prototype species, causing classic hemorrhagic fever with renal syndrome with up to ~10% case fatality in untreated cases. Reservoir: striped field mouse (Apodemus agrarius). Highest case loads occur seasonally in China and Korea. ## Reservoir Apodemus agrarius (striped field mouse) is the principal rodent reservoir. Humans become infected via inhalation of aerosolized excreta in close, dusty environments. ## Transmission Hantaan virus has no documented person-to-person transmission. Cases occur via rodent reservoir contact, not human chains. ## Clinical course Hantaan virus causes hemorrhagic fever with renal syndrome (HFRS). The kidneys are the primary affected organ; patients show oliguria, flank pain, petechiae, and hypotension. Case fatality is approximately 5%. ## Where it is now - China · Shaanxi / Heilongjiang / Yunnan — 11000 cases, 110 deaths (CFR 1%, Annual pattern; China CDC weekly bulletin). China reports more hantavirus cases than any other country — typically 10,000 to 20,000 confirmed HFRS cases annually depending on the cycle phase. Hantaan virus dominates in agricultural regions; Seoul virus in port cities. China uses a bivalent inactivated Hantaan/Seoul vaccine in high-incidence rural counties. - South Korea · Gyeonggi / Gangwon — 400 cases, 12 deaths (CFR 3%, Annual pattern; KDCA infectious disease portal). South Korea reports approximately 300–600 confirmed HFRS cases annually, concentrated in Gyeonggi, Gangwon, and Chungcheong provinces. The disease (Korean hemorrhagic fever) gave its name to the prototype Hantaan virus. KDCA uses inactivated Hantaan vaccine in high-risk military and rural populations. ## Sources - HantaTracker live data: https://hantatracker.app/api/v1/cases - CDC Hantavirus: https://www.cdc.gov/hantavirus/ - WHO DON: https://www.who.int/emergencies/disease-outbreak-news Last reviewed: 2026-05-06. Not medical advice. --- # Seoul virus > Worldwide · syndrome HFRS · case fatality ~1% · YTD reported cases 120. Seoul virus has a global distribution due to its reservoir, the brown rat (Rattus norvegicus), which travels with human commerce. Causes a milder form of HFRS. Notable outbreaks have been linked to laboratory rats and pet rats. ## Reservoir Rattus norvegicus (brown rat) is the principal rodent reservoir. Humans become infected via inhalation of aerosolized excreta in close, dusty environments. ## Transmission Seoul virus has no documented person-to-person transmission. Cases occur via rodent reservoir contact, not human chains. ## Clinical course Seoul virus causes hemorrhagic fever with renal syndrome (HFRS). The kidneys are the primary affected organ; patients show oliguria, flank pain, petechiae, and hypotension. Case fatality is approximately 1%. ## Where it is now - China · Shaanxi / Heilongjiang / Yunnan — 11000 cases, 110 deaths (CFR 1%, Annual pattern; China CDC weekly bulletin). China reports more hantavirus cases than any other country — typically 10,000 to 20,000 confirmed HFRS cases annually depending on the cycle phase. Hantaan virus dominates in agricultural regions; Seoul virus in port cities. China uses a bivalent inactivated Hantaan/Seoul vaccine in high-incidence rural counties. ## Sources - HantaTracker live data: https://hantatracker.app/api/v1/cases - CDC Hantavirus: https://www.cdc.gov/hantavirus/ - WHO DON: https://www.who.int/emergencies/disease-outbreak-news Last reviewed: 2026-05-06. Not medical advice. --- # Dobrava virus > Balkans · syndrome HFRS · case fatality ~8% · YTD reported cases 96. Dobrava-Belgrade virus causes the most severe form of HFRS in Europe with case fatality up to 12%. Reservoir: yellow-necked mouse (Apodemus flavicollis). ## Reservoir Apodemus flavicollis (yellow-necked mouse) is the principal rodent reservoir. Humans become infected via inhalation of aerosolized excreta in close, dusty environments. ## Transmission Dobrava virus has no documented person-to-person transmission. Cases occur via rodent reservoir contact, not human chains. ## Clinical course Dobrava virus causes hemorrhagic fever with renal syndrome (HFRS). The kidneys are the primary affected organ; patients show oliguria, flank pain, petechiae, and hypotension. Case fatality is approximately 8%. ## Where it is now - Russia · Volga / Bashkortostan — 6000 cases, 24 deaths (CFR 0.4%, Annual pattern; Rospotrebnadzor). Russia reports several thousand confirmed HFRS cases annually, dominated by Puumala virus in the Volga region (Bashkortostan being a notable focus) and Dobrava-Belgrade in the south. ## Sources - HantaTracker live data: https://hantatracker.app/api/v1/cases - CDC Hantavirus: https://www.cdc.gov/hantavirus/ - WHO DON: https://www.who.int/emergencies/disease-outbreak-news Last reviewed: 2026-05-06. Not medical advice. --- # Bayou virus > Southeastern United States · syndrome HPS · case fatality ~33% · YTD reported cases 8. Bayou virus is the second most common cause of hantavirus pulmonary syndrome in the United States after Sin Nombre. Reservoir: rice rat (Oryzomys palustris) in the southeastern US. ## Reservoir Oryzomys palustris (rice rat) is the principal rodent reservoir. Humans become infected via inhalation of aerosolized excreta in close, dusty environments. ## Transmission Bayou virus has no documented person-to-person transmission. Cases occur via rodent reservoir contact, not human chains. ## Clinical course Bayou virus causes hantavirus pulmonary syndrome (HPS). After a 1–8 week incubation, patients develop a febrile prodrome followed within days by cough, shortness of breath, and rapid progression to acute respiratory distress. Case fatality is approximately 33% even with ICU care; survival depends on ventilator and ECMO availability. ## Where it is now - United States · Four Corners endemic zone — 17 cases, 0 deaths (CFR 0%, CDC NNDSS, 2026 MMWR week 17 (most recent published)). United States reports approximately 15–40 confirmed HPS cases per year, concentrated in the Four Corners region (Sin Nombre virus). Numbers shown are the most recent CDC NNDSS Weekly publication. ## Sources - HantaTracker live data: https://hantatracker.app/api/v1/cases - CDC Hantavirus: https://www.cdc.gov/hantavirus/ - WHO DON: https://www.who.int/emergencies/disease-outbreak-news Last reviewed: 2026-05-06. Not medical advice.