Hantavirus — preguntas, respondidas

En general, no. La mayoría de las especies de hantavirus —incluidos el virus Sin Nombre, Puumala, Hantaan y Seúl— se transmiten únicamente por contacto con roedores infectados o con sus excrementos, orina y saliva. La única excepción documentada es el virus Andes (ANDV), presente sobre todo en Argentina y Chile. El virus Andes se ha vinculado a una transmisión limitada entre personas, pero solo en casos de contacto estrecho y prolongado (por ejemplo, convivientes o personal sanitario sin protección). El brote del MV Hondius está causado por el virus Andes, motivo por el cual se está realizando rastreo de contactos a nivel internacional pese a lo infrecuente de la transmisión entre humanos.

The MV Hondius 2026 cluster is the first documented hantavirus outbreak linked to cruise ship travel, but the ship environment was not itself the source of transmission. Hantavirus does not spread easily from person to person — the source was an index case who had spent four months in Andes virus-endemic areas of Argentina, Chile, and Uruguay before boarding. Andes virus is the only hantavirus strain with documented (but limited) person-to-person transmission, requiring prolonged close contact. WHO and ECDC assessed the risk to the general public from the MV Hondius cluster as 'low' to 'very low'. The episode demonstrates that travelers returning from Andes-endemic South American regions within 8 weeks of symptoms should disclose that travel history to clinicians immediately.

La incubación del hantavirus suele oscilar entre 1 y 8 semanas tras la exposición, y la mayoría de los casos presentan síntomas entre 2 y 4 semanas después del contacto (CDC). Este periodo de incubación prolongado es uno de los motivos por los que la OMS mantiene la vigilancia activa de los pasajeros y contactos del MV Hondius: con desembarcos en Santa Elena el 24 de abril de 2026 y personas dispersas hoy en 6 países, podrían aparecer nuevos casos vinculados al brote hasta mediados de junio de 2026.

Ebola is NOT airborne. Human-to-human transmission requires direct contact with the blood or body fluids (saliva, vomit, urine, feces, breast milk, semen) of a symptomatic or deceased infected person, or with surfaces and objects contaminated by those fluids. Traditional burial practices involving contact with the deceased are a well-documented transmission route, as is nosocomial spread in healthcare settings lacking adequate infection control. The virus can also persist in semen for months after recovery, making sexual transmission possible. Animal-to-human spillover is believed to originate from fruit bats (Pteropodidae) and infected non-human primates.

El hantavirus se transmite principalmente desde los roedores a las personas por cuatro vías principales: (1) Inhalación de orina, excrementos o saliva aerosolizados de roedores infectados, la vía más frecuente, sobre todo en espacios cerrados y mal ventilados como cabañas, garajes, cobertizos y graneros. (2) Contacto directo con roedores, sus excretas o superficies contaminadas, especialmente con piel lesionada o mucosas. (3) Mordedura de un roedor infectado (poco frecuente). (4) Consumo de alimentos contaminados con excretas de roedor. El virus Andes también presenta una transmisión documentada entre personas, aunque infrecuente, que requiere contacto estrecho y prolongado (por ejemplo, convivientes o personal sanitario sin EPI). El hantavirus no se transmite por mosquitos, garrapatas ni otros artrópodos.

Measles is one of the most contagious infectious diseases known. It spreads through the air via tiny respiratory aerosols and droplets released when an infected person coughs, sneezes, or breathes. The virus can survive in the air and on surfaces for up to 2 hours after an infected person has left a room — meaning you can catch measles without direct contact. The basic reproduction number (R₀) is 12–18: each infectious person can infect 12 to 18 unvaccinated contacts in a susceptible population. An infected person is contagious from about 4 days before their rash appears through 4 days after — roughly 8 days total, often before they know they are sick. Measles has no animal reservoir, which means it can only survive by continuously infecting people. This makes herd immunity — achieved through ≥95% two-dose MMR vaccination — the only sustainable way to stop transmission.

Smallpox spread almost exclusively person-to-person through respiratory droplets and direct contact with skin lesions, and was highly contagious with a basic reproduction number (R0) of 5-7. Mpox is less transmissible: clade IIb (2022 outbreak) spread primarily through close physical and sexual contact, with an estimated R0 of 1.1-2.4 in the MSM community. Mpox also has a zoonotic reservoir (rodents, primates), meaning it can re-enter the human population from animals — unlike smallpox, which had no animal reservoir.

The primary route is contact with the multimammate rat (Mastomys natalensis) — specifically its urine, faeces, or saliva — or by handling and consuming infected rats. Human-to-human transmission occurs through direct contact with blood, urine, faeces, vomit, or other bodily fluids of an infected person. Lassa fever is NOT airborne; casual contact poses minimal risk. Healthcare workers are at risk without adequate PPE. Sexual transmission is documented during convalescence, as the virus persists in semen for up to three months.

El hantavirus no se transmite por vía aérea del mismo modo que la COVID-19 o el sarampión. Se transmite mediante aerosoles que se generan cuando las excretas secas de los roedores (orina, excrementos, saliva) se remueven y quedan suspendidas en el aire localmente, por ejemplo al barrer una cabaña con presencia de roedores o aspirar excrementos secos. Esto implica que la fracción 'aérea' de la transmisión es de corto alcance y depende de condiciones ambientales concretas, no respirable a lo largo del tiempo en espacios compartidos como ocurre con los patógenos respiratorios. La excepción del virus Andes implica contacto estrecho y prolongado entre personas, tampoco una transmisión aérea respiratoria clásica. Una ventilación estándar (abrir ventanas 30 minutos o más antes de entrar en una estancia cerrada) reduce eficazmente el riesgo.

Lassa fever can spread person-to-person, but is far less contagious than diseases like measles or COVID-19. Transmission requires direct contact with the blood, urine, faeces, vomit, or other bodily fluids of an infected person — casual contact, sharing air, or coughing do not spread the virus. Healthcare workers who treat Lassa patients without adequate PPE are at significant risk. Sexual transmission is documented during convalescence because the virus persists in semen for up to three months. Large household clusters are uncommon; most secondary cases occur in healthcare settings without strict infection control. This is in contrast to Ebola, which has caused much larger nosocomial clusters.

Mpox is not classified as a traditional sexually transmitted infection (STI), but sexual contact is an efficient transmission route. During the 2022 clade IIb global outbreak, the majority of cases in high-income countries involved men who have sex with men (MSM), transmitted through close skin-to-skin contact during sex. The virus spreads via direct contact with lesions, rash, or body fluids — circumstances common during sexual activity. However, mpox also transmits through non-sexual close contact (household, healthcare settings), distinguishing it from classic STIs.

A person with measles is contagious from approximately 4 days before the rash appears through 4 days after rash onset — a total infectious window of about 8 days. This means an infected person is spreading measles before they even know they have it, since the rash does not appear until the disease has been progressing for several days. During the prodromal phase (before the rash), the only symptoms are fever, cough, runny nose, and red eyes — easily mistaken for a common cold or flu. This pre-rash contagiousness is one of the main reasons measles outbreaks are so hard to contain: by the time someone is diagnosed, they may have already exposed many others. People with measles should be isolated from others from 4 days before rash onset through 4 days after rash onset, per CDC guidelines.

Ebola virus disease has a historical case-fatality rate of 25-90% depending on strain, with Bundibugyo ebolavirus — the strain driving the active 2026 outbreak in the Democratic Republic of the Congo and Uganda — historically around 25-40%. Per the WHO Situation Report of 18 May 2026, the outbreak had recorded 528 reported cases (2 lab-confirmed in Uganda, 526 under investigation) and 132 deaths, with 668 contacts identified. No vaccine or monoclonal antibody therapy is currently approved for the Bundibugyo strain, unlike Zaire ebolavirus which has Ervebo and two approved antibody treatments. WHO declared the outbreak a Public Health Emergency of International Concern on 18 May 2026.

La mortalidad varía mucho según la especie del virus. El virus Andes y el virus Sin Nombre, que provocan el síndrome pulmonar por hantavirus (SPH), presentan una tasa de letalidad (CFR) del 30-40 %. Las variantes euroasiáticas que causan la fiebre hemorrágica con síndrome renal (FHSR) —Puumala, Hantaan, Seúl— tienen una letalidad inferior: Puumala 0,1-1 %, Seúl ~1-2 %, Hantaan 5-15 %. El brote del MV Hondius corresponde al virus Andes, la cepa más letal. De los 8 casos notificados a fecha de 7 de mayo de 2026, 3 han fallecido: una letalidad del 37,5 % coherente con las estadísticas históricas del virus Andes. No existe un tratamiento antiviral específico; el estándar de atención son los cuidados intensivos de soporte (oxígeno, ventilación, ECMO), que mejoran el pronóstico cuando se inician de forma precoz.

No. Mpox is substantially less dangerous than smallpox. Smallpox had a case fatality rate of approximately 30% and caused disfigurement in survivors. Mpox clade II (responsible for the 2022-2024 global outbreak) has a fatality rate below 1% in high-income settings. Mpox clade I, circulating in Central Africa, carries a higher fatality rate of 1-10%, historically higher in children. Smallpox was eradicated globally in 1980; mpox continues to circulate in animal reservoirs and spreads to humans.

The overall case fatality rate (CFR) is approximately 1%, reflecting the high proportion of mild or asymptomatic cases. In hospitalised patients — who represent the severe end of the spectrum — the CFR rises to 15-25%. Lassa fever accounts for an estimated 5,000 deaths per year across West Africa. Pregnant women in the third trimester face especially high risk: foetal mortality approaches 80%, and maternal mortality is also significantly elevated.

Casi con seguridad, no, según las evidencias actuales. El director general de la OMS declaró públicamente el 7 de mayo de 2026 que el brote del MV Hondius 'no es la próxima COVID'. Hay tres razones estructurales: (1) El hantavirus no se transmite de forma eficiente entre personas; el virus Andes, la única cepa con transmisión humano-humano documentada, requiere contacto estrecho y prolongado, con un R0 efectivo claramente inferior a 1 en cadenas humanas. (2) El reservorio natural (especies concretas de roedores) está limitado geográficamente, de modo que la propagación sostenida exige a los roedores, no solo a las personas enfermas. (3) La elevada mortalidad (30-40 %) frena paradójicamente la propagación al matar u hospitalizar a los huéspedes antes de que puedan contagiar a otras personas: la clásica dinámica de 'demasiado letal para propagarse'. Los operadores de Polymarket coinciden: la pregunta 'Pandemia de hantavirus 2026', tras alcanzar un pico del 38 % por la alarma inicial, se ha estabilizado en el 9 % con 2,2 millones de dólares negociados. La vigilancia continua está justificada por la incubación de 6 semanas, pero una pandemia es muy improbable.

The first symptoms of Ebola virus disease appear 2-21 days after exposure (typically 8-10 days) and include abrupt high fever (≥38.6°C/101.5°F), intense headache, severe muscle pain, extreme fatigue, sore throat, and loss of appetite. By days 3-7 a gastrointestinal phase follows, with profuse watery diarrhoea (up to 10 L/day in severe cases), vomiting, abdominal pain, and hiccups. In roughly half of severe cases, a haemorrhagic phase develops around days 5-10 — bleeding from injection sites and mucosal surfaces, and a non-itchy rash on the trunk by day 5-7. A person is not contagious until symptoms begin.

Los síntomas iniciales del hantavirus y de la gripe se solapan: ambos provocan fiebre, fatiga, dolores musculares y cefalea. Las fuentes clínicas de los CDC señalan cuatro diferencias. (1) El dolor muscular del hantavirus es intenso y se concentra en grupos musculares grandes (muslos, caderas, zona lumbar); el de la gripe es más difuso. (2) El hantavirus rara vez produce síntomas de vías respiratorias altas en fase inicial (sin rinorrea ni dolor de garganta); la gripe sí, con frecuencia. (3) El hantavirus progresa a un deterioro respiratorio rápido entre 4 y 10 días tras el inicio (fase de SPH), un rasgo que no aparece en la gripe. (4) El hantavirus no tiene patrón estacional; la gripe alcanza su pico en invierno. Las guías clínicas de los CDC subrayan que un antecedente de exposición a roedores o de viaje a una región endémica es la información clave que justifica plantear la prueba de hantavirus.

Seek emergency care immediately — do not wait — if any of these three warning signs apply: (1) Severe muscle aches (thighs, hips, lower back) with high fever above 38°C (100.4°F), AND a history of rodent contact or rural travel in South America (especially Argentina, Chile, Uruguay) within the past 8 weeks. (2) Progressive shortness of breath or difficulty breathing appearing 4–10 days after a fever begins — this signals the life-threatening cardiopulmonary phase of Hantavirus Pulmonary Syndrome (HPS), which can deteriorate to respiratory failure within hours. (3) Any influenza-like illness if you were a passenger or crew member aboard MV Hondius (2026 Andes virus cluster) within the past 6 weeks — tell the emergency team about your ship itinerary immediately. CDC clinical guidance emphasizes that outcomes improve significantly with early hospitalization, oxygen support, and ICU monitoring before respiratory failure develops. Hantavirus has a 30–40% case fatality rate in HPS — 'it might be the flu' is a dangerous assumption if the exposure risk factors above apply.

Mpox illness typically lasts 2-4 weeks. A prodromal phase of fever, lymphadenopathy, and fatigue precedes the rash by 1-5 days. The rash phase — lesions progressing macule, papule, vesicle, pustule, scab — lasts 2-3 weeks. A person remains infectious from symptom onset until all scabs have fallen off and new skin has healed beneath them. Milder clade IIb cases from the 2022 outbreak (few lesions limited to the genital area) sometimes resolved in under 2 weeks.

Symptoms begin 6-21 days after exposure. Mild cases present with fever, general weakness, headache, sore throat, and mild gastrointestinal symptoms. Severe cases (about 20% of infections) include high fever, chest pain, vomiting, diarrhoea, facial swelling, and haemorrhagic manifestations (bleeding from gums, nose, or eyes). A key late complication is sensorineural hearing loss, occurring in 25-30% of patients — including those who recover from acute illness — and is often permanent.

Measles begins with 3–4 days of high fever (often above 40°C/104°F), cough, runny nose (coryza), and red, watery eyes (conjunctivitis) — known as the '3 Cs'. A key early sign is Koplik's spots: tiny white or grey-blue dots on the inside of the cheeks, appearing 1–2 days before the rash and pathognomonic (unique) to measles. The hallmark maculopapular rash then starts at the hairline and face, spreading downward to the trunk and limbs over 3 days. Fever peaks when the rash appears, then gradually falls if the illness is uncomplicated. Complications include ear infections (about 1 in 10 children), pneumonia (the leading cause of measles deaths), and, rarely, encephalitis (1–2 per 1,000 cases). A lesser-known long-term risk is immune amnesia: measles can wipe out 11–73% of existing antibody memory for 2–3 years, leaving recovered individuals more susceptible to other infections.

Both diseases begin with fever, headache, back pain, and fatigue, followed by a characteristic rash. The key distinguishing features of mpox are: (1) prominent lymphadenopathy (swollen glands) — absent in smallpox; (2) rash lesions may appear in different stages simultaneously; (3) genital/perianal lesions are common in clade IIb. Smallpox lesions were uniform in stage and deeply embedded in the skin. Mpox lesions evolve through macule, papule, vesicle, pustule, scab, typically over 2-4 weeks. In the 2022 clade IIb outbreak, many cases presented with few lesions limited to the genital area without a classical widespread rash.

La infección por hantavirus suele presentarse en dos fases (CDC). La fase febril inicial, de 1 a 7 días, incluye fiebre, dolores musculares intensos (muslos, caderas, espalda, hombros), fatiga, cefalea, mareo, escalofríos y, en ocasiones, náuseas, vómitos o dolor abdominal. La fase cardiopulmonar tardía, entre 4 y 10 días tras el inicio en los casos de SPH (Andes, Sin Nombre), cursa con tos, dificultad respiratoria, líquido en los pulmones e insuficiencia respiratoria rápidamente progresiva. Las variantes que provocan FHSR (Puumala, Hantaan, Seúl) producen además insuficiencia renal aguda y manifestaciones hemorrágicas. El rasgo clínico que distingue al hantavirus de la gripe o de la COVID-19 es la transición abrupta a un deterioro respiratorio grave en los casos de SPH.

Yes. China reports the world's highest annual burden of hantavirus disease, with roughly 10,000 to 20,000 cases of hemorrhagic fever with renal syndrome (HFRS) each year — mostly caused by Hantaan virus and Seoul virus carried by Apodemus agrarius (striped field mouse) and Rattus norvegicus (brown rat) respectively. Provinces with the highest incidence are Shaanxi, Heilongjiang, Shandong, and Liaoning. The 2025 epidemiological report from China CDC showed continued decline from 1980s peaks (which exceeded 100,000 cases per year) thanks to rodent control programs and the domestic inactivated bivalent vaccine Hantavax (Hantaan + Seoul, licensed in China since 1994). The MV Hondius 2026 outbreak involves Andes virus — a New World strain unrelated to Chinese-endemic strains — and is therefore epidemiologically separate from China's ongoing HFRS background activity. Travelers to China face very low hantavirus risk in urban areas; rural cabins and grain storage with active rodent infestation are the historical exposure setting.

No. Hantavirus is not an identified health risk for Hajj or Umrah pilgrims. Saudi Arabia's Arabian Peninsula geography does not support endemic hantavirus circulation: no rodent species carrying pathogenic hantavirus strains (such as Andes virus, Sin Nombre virus, or Puumala virus) are established in the region. WHO's Eastern Mediterranean Regional Office (EMRO) does not list hantavirus among zoonotic disease priorities for Saudi Arabia or neighboring Gulf states. The MV Hondius 2026 cluster does not involve any Saudi Arabian, Gulf, or Levantine passengers among confirmed cases or priority contact-tracing lists as of May 2026. For Hajj health priorities, WHO and the Saudi Ministry of Health focus on meningococcal meningitis (ACWY vaccine mandatory for many nationalities), MERS-CoV (Middle East Respiratory Syndrome), respiratory infections, heat illness, and food safety. No hantavirus-specific measures are required or recommended for travel to Saudi Arabia or any other country in the Middle East and North Africa region.

Travel to South America remains safe for most itineraries, but travelers should understand the geographically specific risk from Andes virus. Risk zones are rural areas — particularly Patagonia and the Four Corners region of Argentina (Neuquén, Río Negro, Chubut, Santa Cruz provinces), southern Chile (Regions X–XIV), and parts of Uruguay — not major cities such as Buenos Aires, Santiago, or Montevideo. WHO has not issued a travel advisory against South America for hantavirus. The 2026 MV Hondius cluster arose from a single index case who spent four months in these rural endemic areas. Recommended precautions: avoid sleeping or spending extended time in rodent-infested rural huts, barns, or storage buildings; if camping, use elevated sleeping platforms away from field mouse habitat; never sweep rodent droppings in enclosed spaces — wet them first with 1:10 bleach solution before cleaning. Travelers developing fever, intense muscle pain, and respiratory difficulty within 8 weeks of returning from rural endemic areas in Argentina or Chile should disclose that travel history to emergency physicians immediately.

Hantavirus risk follows rodent population cycles, which vary by region and species. United States (Sin Nombre virus): cases peak in late spring and early summer (May–July) in the US Southwest, correlating with the deer mouse (Peromyscus maniculatus) breeding season that drives rodents into human structures — cabins, barns, and outbuildings closed over winter. The CDC notes that 'spring cleaning' of rural cabins without proper precautions (sweeping dry droppings without a mask) is a recurring documented exposure scenario. Scandinavia and Northern Europe (Puumala virus): cases spike in autumn and winter when bank voles (Myodes glareolus) move into homes and farm buildings. Outbreak years correlate with vole population boom cycles every 3–4 years. South America (Andes virus): year-round transmission with no sharply defined peak; cases rise slightly in autumn and winter in Argentina and Chile when cooler temperatures push rodents indoors. The MV Hondius index case was exposed between November 2025 and April 2026 — an autumn-to-early-autumn window in the Southern Hemisphere. Traveler advice: high-risk activities in endemic regions (wilderness camping, cleaning rural structures) carry elevated risk during local rodent breeding seasons. Check CDC country-specific travel advisories before visiting endemic areas.

Las especies de hantavirus se distribuyen globalmente, con especialización regional. América: virus Sin Nombre (región de Four Corners en EE. UU. —NM, AZ, CO, UT— y también CA, OR, WA), virus Andes (Argentina, Chile, Uruguay), virus Bayou y Black Creek Canal (estados de la costa del Golfo en EE. UU.), virus Choclo (Panamá). Europa: virus Puumala (Escandinavia, Báltico, Rusia, Alemania, Francia, Bélgica, presencia limitada en el norte de Italia), Dobrava-Belgrado (Balcanes). Asia: virus Hantaan (China, Corea), virus Seúl (mundial a través de la rata gris), virus Amur (este de Rusia). África: virus Sangassou (Guinea, con enfermedad humana muy limitada). El brote del MV Hondius corresponde al virus Andes procedente de Sudamérica. El buque se encuentra actualmente frente a Cabo Verde (África Occidental, sin hantavirus endémico) en ruta hacia las Islas Canarias, España.

There is no documented endemic hantavirus circulation in the Arabian Peninsula (Saudi Arabia, United Arab Emirates, Qatar, Kuwait, Bahrain, Oman, Yemen) or in the Levant (Jordan, Lebanon, Syria, Iraq, Palestine, Israel). Limited serological surveys in Egypt and Turkey have detected hantavirus antibodies in commensal rodents (likely Seoul virus from Rattus norvegicus), but no clinically significant human cases linked to those reservoirs have been reported. The WHO Eastern Mediterranean Regional Office (EMRO) does not list hantavirus among priority emerging zoonoses for the region. The MV Hondius 2026 outbreak does not currently involve any Middle Eastern country in confirmed-case or contact-tracing lists. Risk to residents and travelers within the region remains very low, including for pilgrims attending Hajj or Umrah in Saudi Arabia, where the primary health concerns remain meningococcal disease, MERS-CoV, respiratory infections, and heat illness.

Italia no tiene casos documentados autóctonos (adquiridos localmente) de enfermedad por hantavirus. El virus Puumala (PUUV) —una especie de hantavirus más leve, causante de FHSR— tiene presencia limitada en algunas regiones alpinas del norte (Trentino-Alto Adigio, Friuli-Venecia Julia), pero sin casos humanos recientes. El ECDC evalúa como 'muy bajo' el riesgo para la población general europea derivado del brote del MV Hondius. Aun así, el Ministerio de Sanidad italiano ha reforzado la vigilancia de los viajeros que regresan de Sudamérica dentro de la ventana de exposición relevante.

Yes — measles is back in the United States and in several other countries in 2026. The US is experiencing its largest measles resurgence in decades: over 2,104 confirmed cases were reported to the CDC by mid-2026, surpassing every annual total since before the disease was declared eliminated in 2000. The outbreak is driven entirely by communities with low two-dose MMR vaccination coverage, not by a change in the virus itself. The measles virus (Measles morbillivirus) is genetically unchanged and the MMR vaccine remains highly effective (97% with two doses). States most affected include Texas, Montana, and others where pockets of unvaccinated individuals allowed the virus to sustain chains of transmission. Globally, WHO reports active outbreaks in Romania, Italy, the Democratic Republic of Congo, and several countries in sub-Saharan Africa and Southeast Asia in 2025–2026. Measles is not 'back' as an endemic pathogen in the USA — elimination status is maintained as long as no continuous year-round chain of domestic transmission is established — but the current outbreak is a serious public-health warning about the consequences of falling vaccination rates.

Nigeria has the highest reported burden, with thousands of cases annually tracked by the Nigeria Centre for Disease Control (NCDC). Sierra Leone, Liberia, and Guinea are also highly endemic. Sporadic cases have occurred in Mali, Ivory Coast, and Benin. International importation has been recorded in Europe and North America among returning travellers. The WHO regularly issues Disease Outbreak News alerts for Nigeria, with peak transmission typically between January and April.

Yes. The United States is experiencing a significant measles resurgence in 2025–2026, with case counts reaching levels not seen since 2019. Outbreaks have been concentrated in communities with low MMR vaccination rates — particularly among unvaccinated children and adults in states including Texas, Montana, and others. Measles was declared eliminated from the USA in 2000, meaning there is no longer sustained year-round transmission; however, outbreaks still occur when unvaccinated travelers import the virus and it spreads through under-immunized pockets of the population. The CDC monitors all cases and recommends two-dose MMR vaccination as the primary prevention measure. International travel to countries with active measles transmission increases exposure risk for unvaccinated individuals. Parents should confirm their children have received two MMR doses on schedule; adults who are unsure of their vaccination history should consult a physician.

The MV Hondius hantavirus cluster (Andes virus, 2026) spans multiple countries across four continents. Countries with confirmed or suspected patients receiving treatment: Netherlands (two confirmed deaths; ship is Dutch-flagged), Germany (patient transferred by medical evacuation), Switzerland (patient hospitalized), South Africa (patient transferred by medical evacuation), and Saint Helena (30 passengers disembarked 24 April 2026). Countries with active contact-tracing operations for passengers or crew who traveled onward: United States (17 American nationals were aboard), United Kingdom, France, Spain (final port call scheduled Las Palmas, Canary Islands, approximately 11 May 2026), Canada, Singapore. Countries involved in the index case's pre-embarkation travel (Andes virus exposure corridor): Argentina (Ushuaia departure port; index case traveled through southern Argentina for four months), Chile, Uruguay. WHO Disease Outbreak News DON599 covers 23 nationalities aboard. ECDC rates the risk to EU/EEA general public as 'very low'.

Hantavirus is diagnosed using a combination of laboratory tests and clinical criteria. The gold standard for Hantavirus Pulmonary Syndrome (HPS) is serology: IgM and IgG ELISA antibody tests that become positive within days of symptom onset. RT-PCR (reverse-transcription polymerase chain reaction) can detect viral RNA in blood during the early febrile phase before antibodies develop, and was used to confirm Andes virus in the MV Hondius cluster cases. Supportive CBC findings include thrombocytopenia (platelets often below 150,000/µL), immunoblasts (activated lymphocytes), hemoconcentration (rising hematocrit), and left-shifted neutrophilia. Chest X-ray and CT show bilateral interstitial infiltrates as HPS progresses to pulmonary edema. Diagnosis typically combines a compatible clinical picture, recent rodent exposure or travel to an endemic area, and confirmatory serology or PCR. Standard influenza or COVID-19 tests will NOT detect hantavirus — physicians must order specific hantavirus serology panels, available through most state and national reference laboratories in the US, EU, Argentina, and Chile.

The MV Hondius 2026 Andes hantavirus outbreak unfolded over six months across four continents. November 2025–April 2026: Patient Zero travels overland for four months through Argentina, Chile, and Uruguay — the endemic zone for Andes virus — before boarding. April 1, 2026: MV Hondius departs Ushuaia, Argentina with 197 passengers and crew from 23 nationalities. April 6: First passenger develops symptoms; hantavirus not yet suspected. April 11: First fatality — a Dutch passenger dies five days after symptom onset; hantavirus identified retroactively from preserved samples. April 24: 30 passengers disembark at Saint Helena (remote South Atlantic island), triggering a global contact tracing operation across six additional countries. May 4: WHO opens Disease Outbreak News DON599 — the first international alert — confirming a multi-country hantavirus cluster. May 5: Polymarket's 'Hantavirus pandemic 2026' market peaks at 38% probability, with $1.3 million in trading volume. May 7: WHO Director-General states the outbreak is 'not the next COVID'; 5 confirmed cases, 2 deaths confirmed; 2,500 diagnostic kits dispatched to five countries. May 11: MV Hondius arrives Las Palmas de Gran Canaria (Canary Islands, Spain) for final disembarkation of remaining 146 passengers. June 2026: Active contact tracing continues in multiple countries within the 8-week incubation window; total confirmed deaths: 3.

The MV Hondius cluster is the active hantavirus outbreak as of 2026. Live counts (confirmed cases, suspected cases, deaths, affected countries, and people under contact tracing) are shown on the homepage KPI bar and refresh hourly from D1. Patients are hospitalized in the Netherlands, Germany, Switzerland, South Africa, and Saint Helena; contact tracing remains active in the United States, Singapore, Canada, France, the United Kingdom, and Spain. WHO, CDC, ECDC, PAHO, and Africa CDC have each issued situational updates. Prediction markets on Polymarket are tracking the probability of WHO declaring a pandemic in 2026 and additional country-specific case confirmations — see the Markets section for live odds. All numbers update hourly from 50+ sources; this FAQ deliberately avoids hardcoded figures so it never goes stale.

A fecha de 7 de mayo de 2026, el brote del MV Hondius registra 8 casos notificados (5 confirmados por pruebas de laboratorio y 3 sospechosos pendientes de confirmación) y 3 fallecimientos. Estos casos se distribuyen en 5 países donde hay pacientes hospitalizados: Países Bajos, Alemania, Suiza, Sudáfrica y Santa Elena. El rastreo de contactos está activo en al menos 6 países más: EE. UU., Singapur, Canadá, Francia, Reino Unido y España. Más allá del brote del Hondius, en regiones endémicas se registran cada año casos esporádicos de hantavirus: típicamente 20-40 al año en EE. UU. (Sin Nombre), 100-200 en Argentina (Andes) y varios miles de casos de FHSR en Eurasia (Puumala, Hantaan, Seúl). Lo inusual del brote actual no es la cifra bruta de casos, sino su huella multinacional vinculada a un viaje en crucero.

No. Mpox is not eradicated. Smallpox is the only human disease ever declared eradicated (WHO, 1980), achieved through a global vaccination campaign. Mpox continues to circulate in animal reservoirs (primarily rodents in Central and West Africa) and causes recurrent human outbreaks. The 2022-2024 global mpox outbreak (clade IIb) led the WHO to declare a Public Health Emergency of International Concern (PHEIC) twice: in 2022 and again in August 2024 when clade I expanded in the DRC and neighbouring countries. Eradication of mpox is not currently feasible given its animal reservoir.

El virus Andes (ANDV) es una especie de hantavirus endémica del sur de Sudamérica, en particular de Argentina, Chile y partes de Uruguay y Bolivia. Toma su nombre de la cordillera de los Andes, donde se distribuye ampliamente su reservorio natural principal, el colilargo común (Oligoryzomys longicaudatus). El ANDV causa el síndrome pulmonar por hantavirus (SPH), con una tasa de letalidad del 30-40 %, y es único entre los hantavirus por su capacidad de transmisión limitada entre personas, demostrada en agrupaciones que se remontan al brote de 1996 en El Bolsón, Argentina. El brote del MV Hondius corresponde al virus Andes, y el caso índice viajó extensamente por Argentina, Chile y Uruguay entre noviembre de 2025 y abril de 2026.

Ebola virus disease (EVD) is a severe, often fatal illness caused by viruses of the Ebolavirus genus (family Filoviridae). Six species are known — Zaire, Sudan, Bundibugyo, Taï Forest, Reston, and Bombali ebolavirus — with case-fatality rates historically ranging 25-90% depending on strain and access to care. The natural reservoir is believed to be fruit bats (Pteropodidae); spillover to humans occurs via contact with infected wildlife, then spreads human-to-human through direct contact with blood or body fluids. The active 2026 outbreak in the Democratic Republic of the Congo and Uganda, declared a WHO Public Health Emergency of International Concern on 18 May 2026, is caused by Bundibugyo ebolavirus, for which no vaccine or monoclonal antibody therapy is currently approved.

Hantavirus is a family of RNA viruses (family Hantaviridae) transmitted primarily from rodents to humans. Depending on the species, it causes two distinct syndromes: Hantavirus Pulmonary Syndrome (HPS), marked by severe respiratory failure and 30–40% mortality in the Americas (Andes, Sin Nombre viruses), and Hemorrhagic Fever with Renal Syndrome (HFRS), affecting the kidneys in Eurasia (Hantaan, Puumala, Seoul viruses) with 1–15% mortality. There is no specific antiviral treatment or internationally approved vaccine. Infection occurs mainly through inhalation of aerosolized rodent excreta (urine, droppings, saliva). In 2026, the primary active cluster involves the Andes virus, linked to the MV Hondius cruise ship.

Lassa fever is an acute viral haemorrhagic illness caused by Lassa mammarenavirus (Arenaviridae family). It is endemic in West Africa — primarily Nigeria, Sierra Leone, Liberia, and Guinea — and was first identified in 1969 in Lassa, Nigeria. The disease is a zoonosis: its primary reservoir is the multimammate rat (Mastomys natalensis). Approximately 80% of infections are mild or asymptomatic; the remaining 20% can progress to severe disease involving haemorrhagic manifestations and multi-organ failure.

A fecha de 7 de mayo de 2026, el MV Hondius se encuentra en aguas territoriales frente a Cabo Verde, con la OMS y un experto médico incorporado a bordo supervisando la evaluación. Está previsto que el buque llegue a Las Palmas, en las Islas Canarias (España), en torno al 11 de mayo de 2026, donde se realizará el desembarco final y el cribado médico de los 146 pasajeros restantes procedentes de 23 países. Los desembarcos previos incluyeron a 30 pasajeros en Santa Elena el 24 de abril y evacuaciones médicas individuales a Sudáfrica, Países Bajos, Alemania y Suiza. El buque zarpó de Ushuaia, Argentina, el 1 de abril de 2026.

Isolation requirements differ by hantavirus species. For most variants (Sin Nombre, Puumala, Hantaan, Seoul): standard contact precautions are sufficient because there is no documented human-to-human transmission. Healthcare workers should use standard PPE (gloves, surgical mask, eye protection) during procedures that generate aerosols from bodily fluids. For Andes virus — the strain in the MV Hondius 2026 cluster — WHO and ECDC recommend upgraded droplet-plus-contact precautions given the documented, albeit rare, human-to-human transmission risk. This means N95 or equivalent respirator, gown, gloves, and eye shield for direct patient care. The CDC advises airborne precautions (negative-pressure room + N95) when performing high-aerosol procedures such as intubation or bronchoscopy on suspected HPS patients. In the MV Hondius outbreak, WHO distributed 2,500 diagnostic kits and issued specific healthcare-worker guidance emphasizing that Andes virus requires a heightened precautionary approach. Household contacts of Andes virus patients should self-monitor for symptoms for 8 weeks from last exposure; they do not require medical isolation unless symptomatic.

Las recomendaciones de prevención de los CDC se centran en minimizar la exposición a los roedores. Las pautas estándar son: (1) Sellar las aberturas mayores de 6 mm en viviendas, cobertizos y cabañas para impedir la entrada de roedores. (2) Capturar a los roedores con trampas de resorte en las zonas problemáticas; no recurrir solo a veneno (los cadáveres deben retirarse igualmente de forma segura). (3) Antes de entrar en edificios cerrados durante mucho tiempo (cabañas, garajes, trasteros), abrir puertas y ventanas al menos 30 minutos para ventilar. (4) Humedecer el polvo y los excrementos con una solución de lejía (1:10) antes de limpiar; nunca barrer ni aspirar en seco los residuos de roedor, ya que se aerosolizan las partículas víricas. (5) Llevar guantes de látex o goma y mascarilla FFP2/N95 al manipular posibles contaminaciones por roedor. (6) Conservar los alimentos en recipientes a prueba de roedores. Para quienes viajen a regiones endémicas, evitar dormir en cabañas o tiendas con presencia de roedores.

Prevention focuses on reducing contact with the multimammate rat (Mastomys natalensis), the primary animal reservoir. Key measures recommended by the WHO and CDC include: (1) Store food in rodent-proof containers and dispose of garbage away from the home. (2) Keep homes clean and seal entry points to discourage rats. (3) Avoid contact with rodents, their nests, urine, or faeces. (4) Healthcare workers must use appropriate personal protective equipment (PPE) — gloves, gowns, masks — when caring for suspected or confirmed Lassa fever patients, and follow strict infection control protocols. (5) Community education in endemic areas (Nigeria, Sierra Leone, Liberia, Guinea) on the risks of handling or consuming rats. There is currently no approved vaccine for Lassa fever, though multiple candidates are in clinical development under CEPI funding.

The MMR (measles-mumps-rubella) vaccine is highly effective. A single dose provides approximately 93% protection against measles; two doses provide approximately 97% protection. The two-dose schedule — first at 12–15 months, second at 4–6 years — is the global standard recommended by WHO and CDC and is why measles was declared eliminated from the USA in 2000. Protection from two doses is generally lifelong for the vast majority of vaccinated people. Adults born before 1957 are presumed immune from prior natural infection. Adults born in 1957 or later who haven't had measles or received two vaccine doses should get vaccinated. The 2025–2026 USA resurgence is driven entirely by communities with low two-dose MMR coverage — not by the vaccine failing, but by vaccination gaps allowing the virus to find susceptible hosts.

WHO and ECDC issued specific guidance for the approximately 197 passengers and crew aboard MV Hondius following the Andes hantavirus cluster. Recommended actions: (1) Self-monitor daily for fever (>38°C / 100.4°F), severe muscle aches in the thighs, hips, or back, fatigue, or any breathing difficulty for 8 weeks from last potential exposure aboard the ship. (2) If symptoms develop, call emergency services immediately and inform them of your travel on MV Hondius — do not self-drive to an emergency room. Provide the ship's name, dates aboard, and cabin number to the receiving healthcare team. (3) Passengers who disembarked at Saint Helena on 24 April 2026 should have already been contacted by local health authorities; if not, contact your national health authority directly. (4) Normal daily activities including work may continue while asymptomatic — Andes virus is NOT spread through casual contact, shared office air, or public transport. (5) Defer blood donation until 8 weeks after disembarkation. WHO distributed diagnostic kits to all countries known to host former passengers or crew, covering 23 nationalities. Your national traveler health hotline can provide country-specific guidance.

Yes. Smallpox vaccines provide cross-protection against mpox because both viruses are orthopoxviruses. The JYNNEOS vaccine (MVA-BN, Imvamune/Imvanex) is specifically approved for both mpox and smallpox prevention. ACAM2000 (the replication-competent vaccinia vaccine) is also protective but carries more side-effect risks. Pre-1980 smallpox vaccination campaigns conferred approximately 85% protection against mpox; that immunity has waned in the global population since routine vaccination stopped. JYNNEOS is now recommended as a 2-dose series for at-risk individuals in many countries.

Survivors of Hantavirus Pulmonary Syndrome (HPS) can make full recoveries, but the critical window is narrow. Once the cardiopulmonary phase begins — typically 4–10 days after symptom onset — patients may deteriorate rapidly from mild dyspnea to full respiratory failure within hours. Early ICU admission with supplemental oxygen, mechanical ventilation, and in severe cases ECMO (extracorporeal membrane oxygenation, heart-lung bypass) is the standard of care and significantly improves survival odds. Most survivors who receive adequate ICU support are discharged within 2–6 weeks. Long-term sequelae: some HPS survivors experience reduced pulmonary function for several months but most regain normal lung capacity within a year. There is no known chronic carrier state for hantavirus — the virus does not persist indefinitely after recovery. Hemorrhagic Fever with Renal Syndrome (HFRS) variants (Puumala, Hantaan) have a better prognosis overall (case fatality 0.1–15%) and renal function typically recovers, though dialysis may be needed acutely. The three deaths in the MV Hondius 2026 cluster occurred before ECMO could be initiated, underscoring that rapid recognition and early ICU transfer are the main modifiable survival factors.

A fecha de mayo de 2026, ninguna vacuna contra el hantavirus ha recibido aprobación de la OMS, la FDA o la EMA. Corea del Sur y China han utilizado a nivel nacional vacunas inactivadas de hantavirus (por ejemplo, Hantavax) para cepas de FHSR (Hantaan, Seúl), pero no están aprobadas internacionalmente y no protegen frente a las cepas del Nuevo Mundo causantes del SPH (Andes, Sin Nombre). Varios candidatos vacunales dirigidos al virus Andes y al virus Sin Nombre se encuentran en fase de investigación temprana y ensayos de fase 1, pero no se espera que ninguno reciba aprobación antes de 2028. La pregunta de Polymarket '¿Vacuna contra el hantavirus aprobada en 2026?' cotiza actualmente con una probabilidad del 2 %.

For Zaire ebolavirus, yes: Ervebo (rVSV-ZEBOV-GP, Merck) has been FDA/EMA-approved since 2019 and is used in ring vaccination during outbreak response, and two monoclonal antibody therapies — Ebanga (mAb114) and Inmazeb (REGN-EB3) — are FDA-approved and reduce mortality when given early. Sudan ebolavirus vaccine candidates are in advanced trials but not yet WHO-prequalified. Critically, the active 2026 outbreak in the DRC and Uganda is caused by Bundibugyo ebolavirus, for which no vaccine or monoclonal antibody therapy is currently approved — treatment there relies on supportive intensive care (fluids, electrolyte balance, oxygen, blood pressure support).

Ribavirin, an antiviral drug, is effective when given early — ideally within 6 days of fever onset. Early supportive care (IV fluids, electrolyte correction, treating secondary infections) also significantly improves outcomes. Convalescent plasma has been explored but its efficacy is not firmly established. There is currently no WHO-approved vaccine for Lassa fever, though multiple vaccine candidates are in clinical development.

There is no approved specific antiviral drug for measles. Treatment is supportive — meaning it aims to reduce symptoms and prevent complications rather than directly kill the virus. Key elements include: adequate hydration, fever management with acetaminophen or ibuprofen (never aspirin in children), and vitamin A supplementation — WHO recommends two high-dose vitamin A doses for all children with measles, as it has been shown to significantly reduce measles mortality and the severity of complications including blindness and pneumonia. Secondary bacterial infections (the most common cause of measles-related deaths in both children and adults) are treated with appropriate antibiotics. Severe pneumonia and measles encephalitis require hospitalization and may need intensive care. The best 'treatment' remains prevention: two doses of MMR vaccine before exposure provide lifelong protection in ~97% of recipients.

Tecovirimat (TPOXX/ST-246) is an antiviral approved by the FDA and EMA specifically for the treatment of orthopoxvirus infections including mpox. Brincidofovir and cidofovir are alternative antivirals used in severe cases. For most people with clade II mpox, illness is self-limiting and resolves within 2-4 weeks with supportive care (pain management, wound care, hydration). Severe cases — clade I infection, immunocompromised patients, children, or extensive skin involvement — require antiviral treatment and may need hospitalisation.

Los dos virus difieren en casi todas las dimensiones que importan epidemiológicamente. Transmisión: la COVID-19 (SARS-CoV-2) se propaga eficazmente entre personas por gotas y aerosoles respiratorios; el hantavirus es principalmente zoonótico (roedor-humano), siendo el virus Andes la única especie con transmisión humano-humano limitada y poco frecuente en contactos estrechos y prolongados. R0 (número reproductivo básico): COVID-19 original 2-3, variantes actuales hasta 8-15; virus Andes con R0 <1 en transmisión humano-humano, lo que hace improbable un brote sostenido. Mortalidad: tasa de letalidad de la COVID-19 del 0,5-2 % poblacional; del hantavirus Andes, 30-40 %. Potencial pandémico: la COVID-19 causó millones de muertes en el mundo; el hantavirus nunca ha provocado una pandemia y la OMS evalúa el riesgo actual como bajo. El brote del MV Hondius, con 8 casos a fecha de 7 de mayo de 2026, ilustra un evento zoonótico contenido, no el inicio de una pandemia.

Hantavirus vs Ébola — mortalidad 30-40 % vs 25-90 %, reservorio roedores vs murciélagos, sin vacuna vs Ervebo. 7 diferencias clave y casos en vivo 2026. (1) Reservorio: hantavirus en roedores (ratones ciervo, topillos); ébola en murciélagos frugívoros y primates no humanos. (2) Transmisión humano a humano: hantavirus rara (solo cepa Andes, contacto estrecho prolongado); ébola sí, de forma eficiente por fluidos corporales, hasta brotes de miles de casos. (3) Mortalidad: síndrome pulmonar por hantavirus (HPS) 30-40 % (virus Andes); ébola 25-90 % según la cepa — ébola Zaire históricamente 50-90 %. (4) Vacuna: hantavirus ninguna aprobada internacionalmente; ébola tiene Ervebo (rVSV-ZEBOV), aprobada por FDA y EMA desde 2019 para el ebolavirus Zaire, más candidatos avanzados para Sudán. (5) Tratamiento: ambos requieren cuidados intensivos de soporte; ébola dispone además de dos anticuerpos monoclonales aprobados por la FDA — Inmazeb (REGN-EB3) y Ebanga (mAb114), que reducen drásticamente la mortalidad si se administran pronto. (6) Brotes principales: hantavirus Argentina 1996, EE.UU. 1993 (Four Corners) y el actual conglomerado MV Hondius 2026. Ébola África Occidental 2014-2016 (28 600 casos / 11 300 muertes), RDC 2018-2020 (3 470 casos / 2 287 muertes), más brotes recurrentes en Uganda. (7) Potencial pandémico: ambos han permanecido regionales; ninguno ha alcanzado el nivel pandémico global. Sigue ambos en vivo: conglomerado MV Hondius en outbreakwatch.net y Ebola Situation Watch 2026 en outbreakwatch.net/ebola.

Both are African viral haemorrhagic fevers, but they differ significantly. Lassa is caused by an arenavirus, Ebola by a filovirus. Lassa is endemic and causes tens of thousands of cases annually; Ebola causes sporadic large outbreaks. Lassa's overall CFR (~1%) is much lower than Ebola's (25-90%), though hospitalised Lassa patients face higher mortality (~15-25%). Lassa does not spread person-to-person as easily as Ebola. Both require similar PPE for healthcare workers.

Mpox and smallpox are both caused by orthopoxviruses, but they are distinct diseases. Smallpox (Variola virus) was eradicated in 1980 and no longer occurs naturally. Mpox (Monkeypox virus) is an ongoing zoonotic disease, with outbreaks in 2022-2024 (clade IIb, global) and 2024-2025 (clade I, primarily Democratic Republic of Congo). Key clinical difference: mpox causes prominent lymphadenopathy (swollen lymph nodes), which does NOT occur in smallpox. Mpox is significantly less severe: clade II fatality rate is under 1%, while smallpox killed approximately 30% of those infected.

Los mercados de predicción están razonablemente calibrados para eventos con abundante actividad de negociación e información pública, pero presentan limitaciones conocidas frente a brotes de enfermedades emergentes. Puntos fuertes: agregan perspectivas diversas y se actualizan rápidamente al llegar nuevos datos. Limitaciones en brotes: (1) liquidez escasa en los mercados de brote temprano; unos pocos operadores pueden mover los precios de forma sustancial. (2) Riesgo de resolución: lo que cuenta como 'declaración oficial de pandemia' puede ser objeto de disputa. (3) Asimetría de información: las autoridades sanitarias manejan datos privados que los operadores no tienen. (4) Reflexividad: cuando los mercados se convierten en noticia, pueden influir sobre el propio fenómeno que predicen. El mercado de Polymarket 'Pandemia de hantavirus 2026' supera ya los 3,5 millones de dólares de volumen: liquidez suficiente para resistir la manipulación por parte de un único operador, pero aún volátil y sensible a las declaraciones de la OMS.

Un mercado de predicción es un mercado en línea en el que los participantes compran y venden acciones cuyo valor depende del desenlace de un evento futuro. En los eventos de sí/no, una acción de SÍ paga 1 $ si el evento ocurre y 0 $ en caso contrario; el precio actual, entre 0 $ y 1 $, representa la probabilidad agregada que el mercado asigna al evento. Por ejemplo, si las acciones de SÍ en '¿Pandemia de hantavirus en 2026?' cotizan a 0,09 $, la probabilidad estimada por la multitud es del 9 %. Entre los principales mercados de predicción están Polymarket (basado en criptomonedas, alcance global) y Kalshi (mercado de derivados regulado en EE. UU.). Los investigadores los utilizan a menudo como señales de pronóstico para eventos que van desde elecciones hasta brotes de enfermedades, ya que la agregación de apuestas de muchos operadores puede producir probabilidades calibradas. OutbreakWatch muestra datos de Polymarket y Kalshi; no facilitamos operaciones de negociación.

El mercado '¿Pandemia de hantavirus en 2026?' de Polymarket ha sido uno de los mercados sanitarios más volátiles del año. Tras su apertura el 4 de mayo de 2026, partió del 3,5 %, subió hasta el 38 % el 5 de mayo cuando aparecieron los primeros informes de transmisión humano-humano y fallecimientos, y volvió a caer al 9 % el 7 de mayo después de que el director general de la OMS describiera públicamente el brote como 'no la próxima COVID'. El volumen total negociado supera ya los 2,2 millones de dólares. Las oscilaciones reflejan una evaluación colectiva en tiempo real de tres señales: (1) cómo enmarca el riesgo la OMS, (2) los nuevos casos notificados fuera del brote inicial del buque, y (3) un periodo de incubación de hasta 6 semanas que implica que podrían seguir apareciendo casos hasta mediados de junio de 2026. El mercado se resuelve el 31 de diciembre de 2026: los apostadores están valorando el riesgo de cola a 8 meses vista.