UKHSA Update On Hantavirus: 2 Nonsymptomatic Passengers Self-Isolating at Home

 

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The UK's Health Security Agency has published an update this afternoon on the current status of British nationals aboard the m/v Honidius, which also includes details on two passengers who apparently already left the ship, and - while showing no symptoms - are self-isolating at home. 

Given the large number of people who have been exposed aboard ship - and an unknown number of contacts offship - the use of home self-isolation (with daily phone check ins) would seem a reasonable precaution; at least until we get a better handle on the infectivity of this strain. 

Whether other jurisdictions will adopt similar measures remains to be seen. The 2-8 week incubation period of the Andes Virus - and its early flu-like presentation - is likely to present public health agencies around the globe with a formidable challenge over the weeks ahead.

UKHSA update on the hantavirus cruise ship outbreak

Latest information on cases including British nationals.
From:UK Health Security Agency Published 6 May 2026




The UK Health Security Agency (UKHSA) continues to work with the World Health Organization (WHO), Foreign, Commonwealth and Development Office (FCDO), the Department of Health and Social Care (DHSC), and other international partners to prepare for the arrival of British nationals to the UK from the MV Hondius cruise ship where an outbreak of Hantavirus was confirmed.

Three people, including one British national, with suspected hantavirus have been evacuated from the Hondius in order to receive medical care in the Netherlands in co-ordination between the Cape Verde, UK and Dutch governments. UKHSA are in close contact with medical teams providing their care.

The remaining British nationals can now be repatriated once the ship docks at its next destination if they do not develop symptoms. None of the British citizens onboard are currently reporting symptoms but they are being closely monitored. The FCDO is making arrangements for these individuals to return to the UK, where UKHSA is working with government to support them to isolate with regular testing and contact with healthcare professionals.

UKHSA is aware of two people who have returned to the UK independently having been on board the MV Hondius. Neither of these individuals is currently reporting symptoms. They are receiving advice and support from UKHSA and have been advised to self-isolate. UKHSA are supporting a small number of individuals identified as close contacts of those on the boat. They are being offered support and are also self-isolating. None are reporting any symptoms. The risk to the general public remains very low.

Dr Meera Chand, Deputy Director for Epidemic and Emerging Infections at UKHSA said:

• Our thoughts are with all those affected by the hantavirus outbreak onboard the MV Hondius.

• It’s important to reassure people that the risk to the general public remains very low. We are standing up arrangements to support, isolate and monitor British nationals from the ship on their return to the UK and we are contact tracing anyone who may have been in contact with the ship or the hantavirus cases to limit the risk of onward transmission.

• UKHSA will continue to work closely with government partners to offer all necessary support.

UKHSA is working closely with the FCDO, the Home Office, and Border Force to trace further individuals who may have been on the same flight as a confirmed case, in order to carry out public health risk assessments and ensure appropriate precautionary measures are in place.

Hantavirus is the name given to a group of viruses carried by rodents and transmitted by their droppings and urine. They can cause a range of diseases from mild, flu-like illness to severe respiratory illness. Infections in humans are rare and tend to occur in places where people and rodents coexist - most commonly in rural, agricultural settings, though the viruses can also sometimes be found in cleaning sheds, barns and holiday homes where rodents might have nested.

Most hantaviruses do not spread easily between humans, although person-to-person transmission has been observed in some cases involving particular strains. The World Health Organization is leading the international response to this incident and overseeing direction of the ship, including advising on how to minimise the risk of the disease spreading.

The FCDO is in direct contact with the ship and has stood up consular teams across multiple countries to support British nationals. UK government is working extremely closely with international partners in response to this incident, including the cruise ship operator and the governments of overseas territories which were visited by the ship.

Further information on Hantavirus can be found in the recent blog from UKHSA.

ECDC: Threat Assessment Brief On Hantavirus Cluster on a Cruise Ship

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With the caveat that it is still early days, we've a Threat Assessment Brief this afternoon from the ECDC on the ongoing outbreak aboard the  m/v Hondius which is currently enroute to the Canary Islands. 

As we've seen often in the past, assumptions and recommendations about exotic or novel disease outbreaks are subject to change as more data is gathered, so stay tuned.  

Due to its length, I've only posted the summary below.  Follow the link to read it in its entirety. 

Hantavirus-associated cluster of illness on a cruise ship: ECDC assessment and recommendations

Assessment
6 May 2026

This is a rapidly evolving incident, and this document contains a preliminary assessment and recommendations. ECDC will provide updates as information becomes available.

As of 6 May 2026, seven cases have been reported in a hantavirus-associated cluster of illness on a cruise ship, including three deaths, one critically ill, two symptomatic and one with unknown status.

Epidemiological situation

ECDC was notified on 2 May 2026 by the Netherlands via the European Union (EU) Early Warning and Response System (EWRS) about a cluster of unknown disease with severe respiratory symptoms on a cruise ship in the South Atlantic, operating under a Dutch flag. There were 149 people on board from 23 different nationalities, including nine EU/EEA Member States: Belgium, France, Germany, Greece, Ireland, the Netherlands, Poland, Portugal, and Spain. At the time, two people had died and one had been medically evacuated to South Africa, where the person remained critically ill. A PCR test result for a sample taken from this person came back positive for hantavirus on 3 May 2026.

As of 6 May, a total of seven people had presented with symptoms that included fever, respiratory symptoms, and gastrointestinal symptoms, with at least four rapidly progressing to pneumonia, acute respiratory distress and shock. Of these seven people, three died, one was medically evacuated to South Africa and admitted to an intensive care unit (ICU), two remained symptomatic on board, requiring medical assistance, and one was diagnosed after disembarking the ship and returning to Switzerland. In total, samples from two patients tested positive for hantavirus by PCR; a sample from one additional patient tested positive for Andes virus (ANDV) by PCR. Further laboratory investigations are ongoing.

Orthohantavirus infections are viral zoonotic diseases transmitted to humans primarily through the inhalation of aerosols contaminated with the urine, faeces or saliva of infected rodents. Human disease can be caused by several orthohantavirus species, including the Andes (ANDV) and Sin Nombre (SNV) viruses in the Americas and Puumala and Dobrava viruses in Europe. The incubation time is usually around two weeks but ranges from seven days up to six weeks.

Clinical manifestation of hantavirus infection is divided in two clinical syndromes: Hantavirus Pulmonary Syndrome (HPS), seen in the Americas; and Haemorrhagic Fever with Renal Syndrome (HFRS) seen in Europe and Asia. Severe cases can rapidly deteriorate and become life-threatening. ANDV is a hantavirus primarily found in South America that causes HPS with a high fatality rate. Human-to-human transmission is rare but has been documented in the case of ANDV. No effective antiviral treatment is available; supportive care is key for a better chance of survival.

ECDC provides this risk assessment for discussion at the level of the Health Security Committee including the involved countries, UK HSA and the WHO.

Risk assessment

Person-to-person transmission of ANDV has only been documented following close and prolonged contact. The current hypothesis is that some passengers were exposed to ANDV while spending time in Argentina before embarking, where ANDV is endemic, and may subsequently have transmitted the virus to other passengers onboard the cruise ship. At this early stage of the investigation with limited available information, we consider everyone on the ship to be close contacts, due to the closed setting and shared social areas and activities, aligned with the precautionary principle.

Measures are already implemented on board to reduce the likelihood of infection for passengers and crew on the cruise ship. The cruise ship company and the relevant port authorities have also been advised on how to prepare for the management of cases and contacts (e.g. isolation of cases, use of appropriate personal protective equipment, testing, etc).

Even if transmission of ANDV were to happen from passengers evacuated from the ship, ANDV does not transmit easily so it is unlikely that it would cause many cases or a widespread outbreak in the community, if infection prevention and control measures are applied.

In addition, the natural reservoir for ANDV is not present in Europe, so introduction to the rodent population and potential rodent-to-human transmission in Europe is not expected.

The risk to the general population in the EU/EEA from ANDV spreading from this cruise ship outbreak is very low.

Recommendations

• Symptomatic people should be managed proactively and medically evacuated as soon as possible.
• Upon disembarking, diagnostic testing should be carried out by serology or PCR in people with symptoms. However, negative test results may not exclude infection and subsequent virus shedding. The EURL-PH-ERZV offers diagnostic services to EU/EEA countries lacking capability to diagnose ANDV infection.
• Passengers and crew should practice usual enhanced precautions (e.g. frequent handwashing, respiratory etiquette, physical distancing) and vigilant symptom monitoring while on the cruise ship.
• Infection Prevention and Control (IPC) guidance for healthcare settings who are caring for symptomatic individuals include standard and droplet precautions, which can be escalated to airborne precautions in the event that aerosol-generating procedures are performed.
• Risk communication should be tailored to the different target groups recognising their different levels of risk, information needs and responsibilities. Communication should clearly state what is known, what is unknown, and what may change as investigations progress with timely updates.
• Disembarking passengers should be provided with clear instructions and recommendations until their diagnosis is confirmed or ruled out.

ECDC actions

• Epidemiological updates.
• Hantavirus infection factsheet published.
• European Union Reference Laboratory (EURL-PH-ERZV) offered assistance to EU/EEA national reference laboratories for the diagnosis of ANDV.
• ECDC is supporting the response operations through the EUHTF remotely and on the cruise ship in coordination with the affected countries.
• Ongoing collaboration with partners and affected countries on common case definitions and protocol for management of cases and contacts.

Hantavirus-associated cluster of illness on a cruise ship: ECDC assessment and recommendations

English (403.61 KB - PDF)

WHO Statement on 8th Hantavirus Case Now Hospitalized in Zurich

 

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While I was tacking down and blogging the statement from the Swiss Authorities the World Health Organization posted their own statement on Twitter/X. 

In this statement, the WHO also acknowledges the identification of the Andes Virus, and states it is working with relevant countries to support international contact tracing of possible cases.

This screenshot was posted shortly after 5am EST. 

Switzerland FOPH: Patient Hospitalized in Zurich with Hantavirus Infection - Left Ship in Late April

 

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Overnight Switzerland has reported that a former passenger on the m/v Hondius - who left the ship (with his wife) in late April to return home to Zurich - has been hospitalized with Hantavirus, and that testing has confirmed the Andes Virus.

While not unexpected, this is the first confirmation of the virus type I've seen. 

Authorities are conducting contact tracing, but are quick to reassure the public that the risk of further cases in Switzerland are low. This does raise the possibility, however, that other non-shipboard cases might arise. 

I expect we'll be getting additional information from the WHO, ECDC, and other relevant authorities in the hours and days ahead. 

Press release published on May 6, 2026
Patient with hantavirus infection is receiving hospital treatment

Bern, May 6, 2026 — A person with a hantavirus infection is currently being treated at the University Hospital Zurich (USZ). The patient is a man who has returned to Switzerland and was previously a passenger on the cruise ship where several hantavirus cases have occurred. The USZ is prepared for such cases, can care for the patient, and ensure the safety of both staff and all patients. There is currently no danger to the Swiss population.

In Switzerland, a person has tested positive for hantavirus. The man had returned from a trip to South America with his wife at the end of April. After experiencing symptoms, he consulted his family doctor by phone and went to the University Hospital Zurich (USZ) for testing. He was immediately isolated. A test conducted at the reference laboratory of the Geneva University Hospital (HUG) confirmed a positive result for hantavirus. Specifically, it is the Andes virus, a hantavirus found in South America. Unlike European hantaviruses, which are transmitted through the excrement of infected rodents, human-to-human transmission of the American hantavirus variant has been observed only rarely. However, transmission only occurs through close contact. Therefore, the Federal Office of Public Health (FOPH) considers the occurrence of further cases in Switzerland unlikely. The risk to the Swiss population is low.

The patient's wife also traveled with him. She is currently asymptomatic and has self-isolated as a precaution. Cantonal authorities are investigating whether the patient had contact with anyone else during his illness. The patient is being treated at the University Hospital Zurich (USZ) under strict safety protocols. The USZ is a designated reference hospital for such illnesses.

The Federal Office of Public Health (BAG) is in close contact with other bodies, such as the Canton of Zurich, the University Hospital of Zurich and Geneva, and the WHO, and is constantly coordinating with them and closely monitoring further developments.

Hantavirus fever is rare in Switzerland. In recent years, there have been between 0 and 6 reported cases per year. Of these few cases, the vast majority were due to infections acquired abroad.

Taiwan CDC: Statement/Update On Locally Acquired H7N7 Infection

 

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Just over a month ago Taiwan reported their first locally acquired human H7 infection (see Taiwan CDC: Human Infection with a Novel H7 Avian Virus), which according to early reports was due to a Eurasian H7 virus.

The patient (a man in his 70s) was hospitalized with fever and pneumonia on March 22nd, and remains hospitalized and in isolation, although his condition was said to be improving. The CDC reported:

Currently, 33 close contacts are under health monitoring and management, and 3 have been given preventative medication based on risk assessment. Tests were conducted on 6 family members, all of whom tested negative.

The following day, in a Taiwan CDC Update: Novel H7 Infection Identified as H7N7.  We also saw a letter to physicians posted on April 8th.  Today we've the first detailed update since then, which reports no further cases have been detected, and assesses the risk to the public as `low'.

Of note, however, is the revelation that the sequenced virus (from the patient) contained the PB2-627K mutation, which is associated with enhanced replication and pathogenicity in mammals (see A rapid review of the avian influenza PB2 E627K mutation in human infection studies).

Since no H7N7 viruses were detected among the birds tested, it is unknown if this mutation was already `fixed' in the avian host, or (as we've seen in other cases) developed spontaneously in the patient.  

While reassuring the public, the CDC notes it is ` . . .  not only closely monitoring genomic evolution but also convening expert meetings to focus on assessing the risk of cross-species transmission . . . '

The full translated update follows:

The first locally transmitted human case of H7N7 influenza A was detected in Taiwan. The agricultural and health authorities launched a joint epidemic prevention and control operation, completing a public health risk assessment that classified the risk as "low risk," and continue to implement epidemic monitoring and prevention and control preparations.
 

Release Date: 2026-05-05

The Taiwan Centers for Disease Control (CDC) announced today (April 5) that regarding the first locally transmitted case of H7N7 novel influenza A reported on April 2 involving a poultry farmer, the CDC has completed gene sequence comparison and analysis. Furthermore, after joint assessment of the overall impact by agricultural and health authorities, the public health risk rating for Taiwan is "low risk."

The CDC pointed out that the patient was discharged from isolation on April 3, and the 33 identified contacts completed health monitoring on April 6, with no confirmed cases of novel influenza A. There is no risk of the outbreak expanding.

This case was discovered due to the high level of vigilance of the hospital physician, who reported the case based on clinical symptoms, contact history, and preliminary test results, leading to confirmation of novel influenza A. Therefore, the CDC will award the reporting physician a NT$10,000 reporting bonus in accordance with Article 5, Paragraph 1, Item 1 of the Infectious Disease Prevention and Control Reward Regulations.

The CDC explained that this case was investigated and controlled through cooperation between health and agricultural authorities, based on the national integrated epidemic prevention action. Gene sequence comparison of the virus showed that it was most similar to the virus strain isolated from wild birds in Japan and South Korea in 2024, and all gene fragments originated from the Eurasian low pathogenic avian influenza virus gene pool, indicating that the virus is highly related to the virus circulating in wild bird populations. 

Further analysis showed that the virus's PB2 gene carries the E627K mutation (PB2 E627K). According to existing research, this mutation may enhance the virus's replication ability in mammalian cells. However, since it cannot be ruled out that this site is a mutation produced in humans after infection, and no virus with the same characteristics has been found in Taiwan recently, nor have any drug resistance-related mutations been detected, the current assessment is that the risk to the public is low. 

In addition, agricultural authorities actively completed sampling at other poultry farms of the case before the Qingming Festival holiday, expanded sampling at five poultry farms near the case, and cooperated with the Wild Bird Association to collect 92 wild bird specimens from the surrounding area, all of which did not detect avian influenza-related viruses.

The Taiwan Centers for Disease Control (CDC) stated that, based on the spirit of national epidemic prevention unity, the CDC also launched a joint risk assessment team with agricultural and health authorities on April 1st to conduct a domestic risk assessment of the H7 subtype viruses (including H7N7, H7N2, H7N3, and H7N4). This risk assessment primarily referenced the framework of the US CDC's Influenza Risk Assessment Tool (IRAT). Team members collected supporting data and scores for ten risk factors and corresponding assessment questions, followed by a comprehensive evaluation. The results showed that the overall risk of the four H7 subtype viruses was low. While the possibility of sporadic local cases in the future cannot be ruled out, direct and indirect contact with animals remains the main transmission route. No evidence of sustained human-to-human transmission has been found, and the possibility of further community spread is extremely low.

In response to the detection of the key PB2 E627K variant in the first domestic H7N7 human infection case and concerns about the lack of herd immunity among the Taiwanese public to the H7 subtype of avian influenza, the Taiwan Centers for Disease Control (CDC) is not only closely monitoring genomic evolution but also convening expert meetings to focus on assessing the risk of cross-species transmission to ensure the disease prevention system can effectively address potential public health threats. Furthermore, the CDC is continuously strengthening the One Health inter-ministerial surveillance mechanism, maintaining surveillance in poultry farms and wild animals, closely monitoring genomic evolution, raising clinicians' awareness of the need for testing cases of pneumonia of unknown cause with a history of contact with poultry or livestock, and enhancing related prevention and control measures such as antiviral drugs.

In its global risk assessment of the H7 subtype of avian influenza, the World Health Organization (WHO) stated that the global H7 subtype of avian influenza is mainly prevalent in wild and domestic poultry populations. Although there have been occasional cases of human infection through contact with infected animals in the past, these cases have mostly presented with mild symptoms such as conjunctivitis or influenza-like illness. The Netherlands reported one death case in 2003. Given the potential impact on public health, close monitoring of human infections of this virus is crucial. Based on the current lack of evidence of sustained human-to-human transmission or community spread, the WHO assesses the threat to public health as remaining low. While sporadic human cases cannot be ruled out, the probability of human-to-human transmission is extremely low.

Argentina MOH: Statement and Special Report On Recent Hantavirus Activity

National Epidemiological Surveillance System (BEN) Week 16

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While the origins of the hantavirus infection currently spreading aboard a cruise ship in the Atlantic remain unknown, the ship embarked from an Argentine port on April 1st, making the Andes Virus a potential suspect.  

Yesterday, the Argentine MOH released a statement, which provides us with additional information on the ship's recent itinerary, along with a recap of hantavirus cases in the region.

First some (translated) excerpts from the statement:

The Ministry of Health is monitoring, along with international organizations, the hantavirus cases reported on the MV Hondius ship.

The national health ministry is maintaining a technical and epidemiological exchange with international and provincial authorities to gather official information on the confirmed cases on the Dutch-flagged cruise ship.

        (Excerpt) 

On May 2, our country's National Centre for Epidemiology received notification of a cluster of severe acute respiratory illnesses on board the cruise ship, including three deaths and one passenger with laboratory confirmation of hantavirus. The transmission route is currently unknown, and further testing is ongoing at the South African National Reference Laboratory to identify the strain and origin of the outbreak. The crew and passengers remain in isolation, and those affected have been transferred to receive the necessary medical care.

The vessel, which had departed from Montevideo, entered the port of Ushuaia on November 16, 2025. From there, it made several coastal voyages between Ushuaia, the Antarctic sector, and the islands of the South Atlantic.

On April 1, 2026, it set sail for South Georgia and the South Sandwich Islands, Saint Helena, and other points in the South Atlantic. The province of Tierra del Fuego reported no significant health-related events.

It is worth noting that Tierra del Fuego has no hantavirus and has not registered any cases since this disease was added to the list of notifiable events in our country in 1996. Its neighboring province, Santa Cruz, only registered one case in 2004. Currently, the Southern region is in a safe zone, with only 10 cases reported in Neuquén, Río Negro, and Chubut during the 2025-2026 season, which began on July 29 of last year.

(Continue . . . )

While the ship has been operating out of a region of the country without any history of hantavirus activity, it is always possible a passenger was exposed somewhere else prior to boarding the ship.

Yesterday the Argentine MOH released an update to their most recent Epidemiological bulletin, with a special focus on Hantavirus activity (and Mpox).  I've provided a translation of the hantavirus section below.

Special Report: Hantavirus

On May 2, the Netherlands National Focal Point (NFP) notified the Argentine NFP of a hantavirus outbreak aboard a cruise ship with 147 passengers and crew from 23 different countries. The ship had departed from Ushuaia, Tierra del Fuego, on April 1 and was following a route through the South Atlantic with multiple stops. The ship is currently off the coast of Cape Verde, the country that will lead the response to the outbreak.

To date, a total of 6 cases have been identified, of which 3 have resulted in death. All passengers and crew are in isolation and maintaining the necessary social distancing to prevent further infections. Patients with compatible symptoms have been transferred to receive appropriate medical care. The National Ministry of Health is in contact with the National Epidemiological Surveillance Centers (NECs) of the countries involved to gather information on the cases' itineraries prior to boarding, the type of contact they had on the cruise ship, and the identification of close contacts. The National Institute of Infectious Diseases (ANLIS) "Carlos G. Malbrán" has also offered advice regarding laboratory diagnosis and the possibility of performing sequencing and genomic analysis of the samples.

Given this situation, the National Epidemiological Surveillance System (BEN) reports that since epidemiological week 13, 9 new cases have been reported nationwide, located in Buenos Aires Province (4 cases), Salta (3 cases), Jujuy (1 case), and Chubut (1 case). So far this year, 42 new cases have been reported, and since the beginning of the season (epidemiological week 27 of 2025), the total number of confirmed cases has reached 101.

The majority are concentrated in the Central region, with Buenos Aires Province reporting the most confirmed cases (42). However, the highest incidence rate corresponds to the Northwest region (0.60 cases per 100,000 inhabitants), where 36 confirmed cases have been registered, 83% of which are concentrated in Salta.

Regarding the cases reported in the Southern region, the National Epidemiological Surveillance System (BEN) reports that one of the confirmed cases in Río Negro corresponds to the town of Río Colorado, located outside the historically endemic areas for hantavirus. In this context, environmental investigations were carried out in this town and other neighboring areas, and four potential exposure sites were identified. No species known to be reservoirs of pathogenic hantavirus were captured, and the specimens obtained tested serologically negative. Based on these findings, the jurisdictions were recommended to implement periodic environmental monitoring to assess the composition of rodent populations during periods of peak abundance and to identify the environments associated with reservoir species.

Finally, during the current season, an intrafamilial cluster was recorded in the town of Cerro Centinela (Chubut), involving three related cases (cohabiting individuals) with sequential symptom onset dates.

Following notification of the index case, the province conducted an environmental focus study and recorded the presence of wild rodents known as hantavirus reservoirs. One of the captured specimens even tested positive for the hantavirus. The epidemiological characteristics of the event raised suspicion of person-to-person transmission, prompting genomic analysis of the human samples. The results indicated that the sequences corresponded to the Andes virus, with a 99.99% similarity among the three cases analyzed. The results of the genomic sequencing of the virus detected in the seropositive rodent are still pending.

        (Continue . . . )
 

As the following MOH graphic illustrates, hantavirus activity tends to peak in the summer in Argentina (Nov-Dec-Jan), and reaches its nadir in the winter (May-Jun-Jul).  It is still fairly active in March and April.

We'll know a lot more once sequencing of the virus is complete, which will hopefully become available this week. 

Stay tuned.