CDC HAN #00530: Ebola Disease Outbreak in the Democratic Republic of the Congo and Uganda

 
Credit CDC

#19,168

While the full extent of the Ebola outbreak in the DRC and neighboring countries remains unclear, we are already seeing numbers that suggest this virus is spreading rapidly in the community.   

The latest CDC update reads:

New developments

• On May 17, an American who was exposed as part of their work caring for patients in DRC tested positive for Ebola Bundibugyo disease.

• The person developed symptoms over the weekend and tested positive late on Sunday.
• CDC is working hand-in-hand with the U.S. Department of State to move the patient to Germany for treatment and care. In addition to being a shorter flight time, Germany has previous experience caring for Ebola patients.
• High-risk contacts associated with this exposure are also being moved to Germany. 

• As of May 19, the DRC and Uganda Ministries of Health report the following:

• A total of 536 suspected cases, 105 probable cases, 34 confirmed cases, and 134 deaths
• In the last 24 to 48 hours, 26 new confirmed cases and 143 new suspected cases were identified,
• These numbers include 2 confirmed cases including 1 death in Uganda in people who traveled from DRC. No further spread has been reported.

• On May 18, CDC, the Department of Homeland Security, and other appropriate federal agencies took proactive public health measures to prevent Ebola from entering the United States.

• This is a rapidly evolving situation, and case counts are subject to change.
• More information about enhanced travel security measures is forthcoming.

Late yesterday afternoon the CDC issued the following lengthy HAN Advisory.  I've only posted some excerpts.  Those with specific interests (clinicians, public health workers, lab techs, etc.) will want to read the advisory in its entirety. 

I'll have a brief postscript after the break. 

Ebola Disease Outbreak in the Democratic Republic of the Congo and Uganda
May 19, 2026

 Distributed via the CDC Health Alert Network
May 19, 2026
CDCHAN-00530

Summary

The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory to alert clinicians, public health practitioners, and travelers about a new outbreak of Ebola disease in the Democratic Republic of the Congo (DRC) and Uganda caused by the Bundibugyo virus (species Orthoebolavirus bundibugyoense).

The risk of spread to the United States is considered low at this time. As a precaution, this Health Advisory summarizes CDC recommendations for U.S. health departments, clinical laboratories, and healthcare workers about potential Ebola disease case identification, testing, and biosafety considerations in clinical laboratories.

Background

On May 15, 2026, the Ministry of Health of the Democratic Republic of the Congo (DRC) confirmed an outbreak of Ebola disease in Ituri Province in northeastern DRC. As of May 16, 2026, a total of 246 suspected cases and 80 deaths have been reported. Laboratory analysis conducted by the National Institute of Biomedical Research (INRB) confirmed the cause as Bundibugyo virus infection in 8 of 13 samples collected from suspected cases associated with clusters of severe illness and deaths in the Mongbwalu and Rwampara health zones in Ituri Province. Patients presented with symptoms including fever, generalized body pain, weakness, vomiting, and in some cases bleeding. Several patients reportedly deteriorated rapidly and died. The outbreak is occurring in areas affected by insecurity, population displacement, mining-related population movement, and frequent cross-border travel, all of which may increase the risk of further transmission. In neighboring Uganda, health authorities confirmed Bundibugyo virus disease (BVD) in a patient who had traveled from DRC and later died while receiving care. Ugandan authorities have activated surveillance, screening, and response measures.

On May 15, 2026, CDC issued a Level 1 Travel Health Notice for people traveling to Uganda and a Level 3 Travel Health Notice for people traveling to DRC. On May 17, the World Health Organization determined this outbreak to be a public health emergency of international concern. As of May 18, no suspected, probable, or confirmed Ebola cases related to this outbreak have been reported in the United States.

This is the 17th recorded Ebola outbreak in DRC since the virus was first identified in 1976. The previous Ebola outbreak in DRC ended in December 2025. The Bundibugyo species of Ebola virus was first identified in Uganda in 2007 and has historically been associated with somewhat lower case fatality rates than other species of Ebola virus disease, though severe disease and death can still occur. Previous outbreaks of BVD have had mortality rates of approximately 25%-50%.

CDC is working through its country offices and partners in DRC and Uganda to provide technical assistance with disease tracking and contact tracing, laboratory sample collection and testing, virus sequencing, infection prevention and control (IPC) efforts, border health screening, and coordination with affected countries and international public health partners. Case numbers are subject to change as the situation evolves.

The risk of spread to the United States is considered low at this time. However, it is possible for travelers from affected areas in DRC or Uganda to enter the United States. Therefore, as an additional precaution, CDC is working to raise awareness of this outbreak among travelers, public health departments, public health and clinical laboratories, and healthcare workers in the United States.

Ebola disease is caused by a group of viruses known as orthoebolaviruses (formerly ebolavirus). Ebola disease most commonly affects humans and nonhuman primates, such as monkeys, chimpanzees, and gorillas. Four orthoebolaviruses cause illness in people, presenting as clinically similar disease:

• Ebola virus (species Orthoebolavirus zairense) causes Ebola virus disease.
• Sudan virus (species Orthoebolavirus sudanense) causes Sudan virus disease.
• Taï Forest virus (species Orthoebolavirus taiense) causes Taï Forest virus disease.
• Bundibugyo virus (species Orthoebolavirus bundibugyoense) causes Bundibugyo virus disease.

The incubation period for BVD ranges from 2 to 21 days after exposure. A person infected with an orthoebolavirus is not considered contagious until after symptoms appear. Early "dry" symptoms include fever, aches, pains, and fatigue and later "wet" symptoms include diarrhea, vomiting, and unexplained bleeding. Ebola disease is spread through direct contact (through broken skin or mucous membranes) with the body fluids (e.g., blood, urine, feces, saliva, semen, or other secretions) of a person who is sick with or has died from Ebola disease. Ebola disease can also be transmitted to humans from infected animals, or through contact with objects like needles that are contaminated with the virus. Ebola disease is not spread through airborne transmission.

In the absence of early diagnosis and appropriate supportive care, Ebola disease has a high mortality rate. There is currently no Food and Drug Administration (FDA)-licensed or authorized vaccine to protect against Bundibugyo virus infection. The Ebola vaccine licensed in the United States (ERVEBO®) is indicated for preventing Ebola disease due to a different species of Ebola virus (species Orthoebolavirus zairense) only, and based on studies in animals, this vaccine is not expected to protect against Bundibugyo virus or other orthoebolaviruses. There is currently no FDA-approved or authorized treatment for BVD, but there are therapies that have shown some efficacy in animal models. With intense supportive care and fluid replacement, mortality rates may be lowered.

CDC has developed recommendations for U.S.-based organizations (e.g., nongovernmental, faith-based, academic, or aid organizations) with staff working in affected areas: Recommendations for Organizations Sending U.S.-based Personnel to Areas with VHF Outbreaks.

Recommendations for Clinicians

Recommendations for Public Health Departments

Recommendations for Clinical Laboratory Biosafety

Recommendations for U.S. Travelers

CDC recommends avoiding nonessential travel to Ituri and Nord-Kivu provinces in DRC. If they travel to DRC, travelers should take precautions as described in CDC's level 3 Travel Health Notice, including taking steps to avoid possible exposure to BVD and monitoring themselves for symptoms while in DRC and for 21 days after leaving. Travelers who develop symptoms during this time should self-isolate and contact local health authorities or a clinician.

Travelers to Uganda are recommended to follow recommendations in CDC's level 1 Travel Health Notice including taking steps to avoid possible exposure to BVD and monitoring themselves for symptoms while in Uganda and for 21 days after leaving. Travelers who develop symptoms during this time should self-isolate and contact local health authorities or a clinician.

Recommendations for the Public

• Protect yourself and prevent the spread of BVD when living in or traveling to a region where Bundibugyo virus is potentially present or that is currently experiencing an outbreak.
• In affected areas, take the following actions to protect yourself: 

• Avoid contact with sick people who have symptoms such as fever, muscle pain, and rash.
• Avoid contact with blood and other body fluids.
• Avoid materials possibly contaminated with blood or other body fluids of people who are sick.
• Avoid semen from men who have recovered from BVD until testing shows that the virus is no longer in the semen.
• Avoid visiting healthcare facilities for nonurgent medical care or for nonmedical reasons.
• Avoid visiting traditional healers.
• Do not participate in funeral or burial practices that involve touching the body of someone who died.
• Keep away from bats, forest antelopes, non-human primates (e.g., monkeys, chimpanzees, gorillas), and avoid contact with blood, fluids, or raw meat from these or unknown animals.
• Do not enter areas where bats live, such as mines or caves.

• Monitor your health while you are in, and for 21 days after you return from, an area experiencing a BVD outbreak.

• If you develop any symptoms of BVD during this time, isolate (separate) yourself immediately from others, do not travel, and contact local health authorities or a healthcare facility for advice.
• Before you enter a healthcare facility, alert the healthcare providers of your recent presence in a BVD-affected area.

Over the past 3 weeks we've seen 2 viral outbreaks (hantavirus & Ebola) emerge from out of left field - and while I believe both will be contained - it is a reminder of how quickly the viral landscape can change. 

The next pandemic virus is likely already out there, in a bat, a mouse, or a bird; just looking for the right opportunity (or evolutionary change) to enable it to jump species and begin its world tour. 

Meanwhile we continue to dismantle our global surveillance and reporting systems, we resist aggressive testing of livestock, and we've cut funding for both basic research and public health systems.

But at least when next pandemic crisis invariably does appear, our leaders will be able to shake their heads and honestly say; `No one saw it coming.'

Norway Veterinary Institute Reports HPAI H5N5 In Polar Bears on Svalbard Island

 

Credit: Multiple transatlantic incursions of HPAI 

clade 2.3.4.4b A(H5N5) virus into North America 

and spillover to mammals

#19,167

Although H5N1 remains the overwhelmingly dominant HPAI H5 subtype reported around the globe, we continue to follow other H5 subtypes bubbling up around the globe. 

• Last February, in South Korea: H5N9 Rising, we looked at concerns over the arrival this past winter of a triad of HPAI H5 viruses in Korea; H5N1, H5N6, and H5N9.

• In Mexico, HPAI H5N2 has recently emerged, infecting both humans and poultry (Preprint: Emergence of a Novel Reassorted HPAI A(H5N2) Virus Associated with Severe Pneumonia in a Young Adult).

• Earlier this month China reported their 93rd human infection with HPAI H5N6, which has resulted in 58 deaths (62.4% CFR)

• In both Europe and in Eastern Canada, we've seen sporadic reports of HPAI H5N5 (see Cell Reports: Multiple Transatlantic Incursions of HPAI clade 2.3.4.4b A(H5N5) Virus into North America and Spillover to Mammals) since 2023.

• Additionally, HPAI H5N5 infected and killed a resident of Washington State last November, via contact with backyard birds.  

While running a distant 2nd place to H5N1, H5N5 has shown surprising tenacity as it expands its geographic range, and reassorts with other LPAI viruses (see March 2026's Viral Creep: H5N5 Update)

In the summer of 2022, the Norwegian Veterinary Institute reported both H5N1 and H5N5 for the first time in wild birds on Svalbard, which lies above the Arctic circle (see More HPAI (H5N5 & H5N1) Detected In Arctic (Svalbard).

Since then we've been tracking a small - but growing - number of spillovers of H5N5 to mammals in both Europe and Canada, including seals in the UK, domestic cats in Iceland, and raccoons (and other small mammals) in Canada.

Two summers ago (2024) in Cell Reports: Multiple Transatlantic Incursions of HPAI clade 2.3.4.4b A(H5N5) Virus into North America and Spillover to Mammals, researchers reported finding the mammalian adaptive E627K mutation in a number of samples.

While we typically see a drop in HPAI reports over the summer, it is because many of their avian hosts have migrated to their high latitude roosting spots - where they may find new opportunities to reassort and evolve - before returning next fall.  

All of which brings us to a new report from the Norway Veterinary Institute, which describes the recent detection of HPAI H5N5 virus in both a dead walrus and a polar bear on Svalbard Island. 

Although no other animals were confirmed infected during this investigation, there are eye witness accounts of two other polar bears exhibiting potential neurological symptoms. 

I've reproduced the NVI statement below. Follow the link for additional photos and references.       

 (Translation)

First detection of avian influenza in polar bears in Svalbard
Published 19.05.2026

The Norwegian Veterinary Institute has detected avian influenza in a one-year-old male polar bear and an adult walrus in Raudfjorden north of Spitsbergen. This is the first time the virus has been detected in polar bears in Norway and Europe.

Avian influenza virus was detected in a brain sample from the polar bear.  

The detected avian influenza virus (HPAI) is of the subtype H5N5, a type of the virus that has also been previously detected in Svalbard: In wild birds in 2022, in a walrus in 2023 and in mountain foxes in 2025. This latest detection is the first in polar bears in Norway and Europe. *

Avian influenza viruses have also previously been detected in carnivorous mammals such as red foxes, otters and lynxes on mainland Norway after infection from wild birds.

Sampled in the field

In mid-May, the Norwegian Veterinary Institute was notified by the Norwegian Polar Institute of the discovery of a dead polar bear and a dead walrus in Raudfjorden on Svalbard. The animals were first observed by tourist guides. Two polar bears were also observed in the area showing lameness in their hind legs. This may be a neurological sign, which has previously been observed in polar bears infected with rabies and predators infected with highly pathogenic avian influenza.

"This gave us suspicion of a serious infectious disease, and two of us from the Veterinary Institute traveled to Svalbard to assist the Governor with sampling the dead animals in the field. With the help of a helicopter, the carcasses were quickly found and we were able to take samples. We observed no more sick polar bears from the air," says veterinarian and wildlife health specialist Knut Madslien.Walrus carcass on the shore in Svalbard. Despite the walrus being very rotten, it was still possible to detect the bird flu virus in the brain.  

The samples were then sent to the Veterinary Institute and tested for avian influenza virus and rabies virus. Highly pathogenic avian influenza (HPAI) virus was detected in the samples from both the polar bear and the walrus. Rabies virus was not detected.

Bird flu virus is circulating in the highlands

"The findings are part of a trend where highly pathogenic avian influenza virus is increasingly being detected in mammals in Europe. At the same time, the virus has spread to new areas in recent years, including the Arctic, where it may have consequences for vulnerable populations and ecosystems," explains Ragnhild Tønnessen, avian influenza coordinator at the Norwegian Veterinary Institute.

“It is important to monitor the situation to understand developments and manage risk,” says Madslien.

Increased infection pressure in mammals

Most avian influenza viruses are best adapted to be transmitted between birds. However, mammals can sometimes be infected with avian influenza through direct contact with birds or other mammals infected with the virus, either sick or dead.

The Veterinary Institute will conduct further investigations of the detected virus to check whether it shows signs of being specifically adapted to mammals.

First detection in polar bears in Europe

In other predators, such as red foxes and lynxes, avian influenza can cause clinical signs of brain disease similar to those seen in rabies. Neurological signs such as circling gait, tilted head position, paralysis, and decreased shyness towards humans are common.

Avian influenza virus in polar bears has been scientifically published once before, in a young male polar bear found dead in Alaska in August 2023. It is not known how the virus affects individual individuals and the polar bear population.

Report if you observe dead or sick animals and birds

Both highly pathogenic avian influenza and rabies are serious diseases that can be transmitted to humans. Therefore, it is important to avoid contact with sick animals.

If avian influenza is suspected in birds and other animals on the mainland, the Norwegian Food Safety Authority must be notified . If sick or dead animals are observed in Svalbard, it is important that the findings are reported to the Governor .

The Norwegian Veterinary Institute is the national reference laboratory for avian influenza and has molecular methods for the detection and characterization of avian influenza viruses.

CDC HAN #00529: 2026 Hantavirus Outbreak: Testing for Potential Infection

Credit CDC


#19,166

Lest we forget with all that is going on with the Ebola outbreak in central Africa; the world is still on watch for additional cases of the Andes virus stemming from the outbreak aboard the m/v Hondius. 

Yesterday the CDC released a HAN (Health Alert Network) update on this outbreak (see below). While of primary interest to clinicians, I've reproduced it below.

This update also reminds clinicians to consider other hantaviruses (New World & Old World) when confronted with patients with suggestive symptoms and exposure to sylvatic rodents or rodent excreta. 

First the HAN update, then I'll return with a bit more.

2026 Hantavirus Outbreak: Testing for Potential Infection
May 18, 2026

At a glance
Distributed via the CDC Health Alert Network
May 18, 2026
CDCHAN-00529



Summary

The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Update to inform clinicians and health departments about testing available for patients with suspected hantavirus infection to include Andes virus. CDC first issued a Health Advisory (CDCHAN-00528) about this outbreak on May 8, 2026.

Hantaviruses are a group of viruses that typically spread to people who come in contact with sylvatic rodents. These viruses can cause severe illness or death in humans. Andes virus, a type of hantavirus endemic in South America, is the only type of hantavirus that is known to spread from person to person. Several other New World hantaviruses are endemic to the United States and are not transmissible from person to person. New World hantaviruses can cause hantavirus pulmonary syndrome (HPS), a potentially serious disease that can cause damage to the lungs.

On May 2, 2026, an outbreak of Andes virus on a cruise ship was reported to the World Health Organization (WHO). This outbreak has raised the possibility of cases being imported to the United States. As of May 18, no confirmed cases of Andes virus associated with the outbreak on the cruise ship have been reported in the United States. Therefore, the overall risk to the American public is still considered extremely low at this time. CDC and health departments in several states are monitoring the health of U.S. passengers from the ship and U.S. air travel contacts of symptomatic ship passengers who were subsequently confirmed to have Andes virus infection. This Health Update informs clinicians about testing and consultation that are available for Andes virus and other hantaviruses endemic to the United States, South America, and other nations.

Background

On May 2, 2026, WHO was notified of a cluster of severe acute respiratory illness (SARI) among passengers and crew aboard the M/V Hondius cruise ship in the Atlantic Ocean. On May 6, 2026, WHO confirmed that the cluster was caused by Andes virus, a hantavirus endemic in areas of South America that can cause hantavirus pulmonary syndrome (HPS). Andes virus is the only hantavirus known to spread from person to person. This type of transmission is rare for hantaviruses and is generally associated with prolonged close contact. As of May 15, WHO has reported 10 cases (8 of them laboratory-confirmed), including 3 deaths.

Hantaviruses cause two syndromes. Hantaviruses found in the Western Hemisphere are often referred to as New World hantaviruses and can cause HPS. Several New World hantaviruses that do not spread person to person are endemic in the United States. These include Sin Nombre virus, the virus mostly commonly associated with U.S. HPS cases. In addition to HPS, hantaviruses can cause other clinically significant illness. Hemorrhagic fever with renal syndrome (HFRS) is a group of clinically similar illnesses that affect the kidneys. HFRS is caused by another group of hantaviruses, often referred to as Old World hantaviruses, that are found mostly in Europe and Asia. However, Seoul virus, a type of hantavirus that causes HFRS, is found worldwide, including in the United States. Non-HPS hantavirus infection can also occur, in which patients experience non-specific viral symptoms without cardio-pulmonary symptoms.

Hantavirus infections can occur year-round but are reported more frequently during the spring and summer months when rodent populations increase and people may have greater exposure to rodent-infested environments such as cabins, sheds, campsites, and homes. The most common hantavirus that causes HPS in the United States is spread by the deer mouse. Andes virus is spread primarily by the long-tailed pygmy rice rat (Oligoryzomys longicaudatus).

Recommendations for Clinicians

Consider Andes virus infection in patients who

(1) have symptoms compatible with hantavirus infection,

AND

(2) were aboard the M/V Hondius cruise ship OR had direct contact with someone associated with the M/V Hondius Andes virus outbreak.

Contact your state, tribal, local, or territorial health department immediately to report a suspected Andes virus case and for assistance with diagnostic testing for Andes virus. 

Know that assays designed to specifically detect Andes virus may not detect other New World hantaviruses endemic in the United States.

Consider infection with other New World hantaviruses in patients who

(1) have symptoms compatible with hantavirus pulmonary syndrome (HPS) or non-HPS hantavirus infection,

AND

(2) have a history of known or suspected exposure to sylvatic rodents or rodent excreta (e.g., urine, droppings, or nesting materials).

Consider infection with Old World hantaviruses in patients who

(1) have symptoms consistent with hemorrhagic fever with renal syndrome (HFRS),

AND

(2) have a history of known or suspected exposure to sylvatic rodents or rodent excreta (e.g., urine, droppings, or nesting materials).

Test for non-Andes hantavirus in patients who have symptoms compatible with hantavirus infection and have a history of rodent exposure, but who are not associated with the M/V Hondius Andes virus outbreak.

Consult with CDC's Viral Special Pathogens Branch (VSPB) to discuss hantavirus diagnostic testing by calling the CDC Emergency Operations Center at 770-488-7100 and requesting VSPB's on-call epidemiologist. VSPB cannot accept specimens without prior consultation.

        (Continue . . . )

As we discussed last year, in Two Recent Studies On the Host Range of Hantaviruses In the United States, hantavirus infections are likely under reported in this country.

Credit CDC

Most Hantavirus cases are sporadic, but occasionally we see clusters. Exposure is often linked to cleaning out sheds and garages in the late spring and summer when mouse activity is high. The CDC has a 20-page PDF guide on reducing exposure risks.

For some past blogs on Hantaviruses, you may wish to revisit:

Argentina's Growing Hantavirus Outbreak

MMWR: A Little Bit Of Seoul (Virus)

Hantaviruses: Of Mice And Men

MMWR: Yosemite Hantavirus

CDC Statement on the Use of Public Health Travel Restrictions to Prevent the Introduction of Ebola Disease into the United States

Scheduled airline traffic around the world – Credit Wikipedia

#19,165

While reassuring the public that the current risk to Americans from the Ebola outbreak in the DRC is `low', yesterday the CDC announced enhanced screening of travelers and imposed `Entry restrictions on non-US passport holders'  if they have visited Uganda, DRC, or South Sudan in the past 3 weeks.

This invocation of Title 42, and a de facto `travel ban' for non-US passport holders is noticeably more restrictive than what we saw during the 2014-2015 Ebola outbreak in West Africa (see CDC Statement On Airport Screening Of Arrivals From West Africa).

First the CDC statement, after which I'll return more on the checkered history of interdicting diseases at ports of entry. 

CDC Statement on the Use of Public Health Travel Restrictions to Prevent the Introduction of Ebola Disease into the United States

For Everyone
May 18, 2026

What to know

On May 18, 2026, CDC, DHS, and other appropriate federal agencies implemented enhanced travel screening, entry restrictions, and public health measures to prevent Ebola disease from entering the United States amid ongoing outbreaks in East and Central Africa.

Statement on Title 42 Order

Title 42 Order

Title 42 Order Suspending the Right to Introduce Certain Persons from Countries Where a Quarantinable Communicable Disease Exists

The Centers for Disease Control and Prevention (CDC), and the Department of Homeland Security (DHS), and other appropriate federal agencies, are taking proactive measures to protect the health and safety of the American public in response to ongoing Ebola Virus Disease (EVD) outbreaks.

Under authority granted by Sections 362 and 365 of the Public Health Service (PHS) Act, 42 U.S.C. §§ 265, 268, and their implementing regulations, CDC is implementing targeted public health measures intended to reduce the risk of Ebola disease caused by the Bundibugyo virus (EVD) by preventing its introduction into the United States. These actions are based on current epidemiological evidence, ongoing risk assessments, and the highly serious nature of EVD. This order will be in effect for 30 days, effective immediately.

Effective immediately, CDC will:

• Enhance public health screening and traveler monitoring for individuals arriving from areas affected by Ebola outbreaks in the region.
• Entry restrictions on non-US passport holders if they have been in Uganda, DRC, or South Sudan in the previous 21 days.
• Coordinate with airlines, international partners, and port-of-entry officials to identify and manage travelers who may have been exposed to Ebola virus.
• Enhance port health protection response activities, contact tracing, laboratory testing capacity, and hospital readiness nationwide.
• Continue deployment of CDC personnel to support outbreak containment efforts in affected regions.

At this time, CDC assesses the immediate risk to the general U.S. public as low, but we will continue to evaluate the evolving situation and may adjust public health measures as additional information becomes available.

If you have traveled through the affected countries you are encouraged to monitor CDC travel health notices and seek medical attention immediately if you develop symptoms consistent with Ebola, including fever, weakness, vomiting, diarrhea, or unexplained bleeding, within 21 days of travel to affected areas.

As we discussed in 2014's The New Normal: The Age Of Emerging Disease Threats, the reality of life in this third decade of the 21st century is that disease threats that once were local, can now spread globally in a matter of hours or days.

Between asymptomatic (or presymptomatic) carriage, and long incubation periods, vast oceans and prolonged travel times no longer protect us against infected travelers crossing borders.

Globally, airlines handle over 5 billion passengers and over 40 million flights per year; that's roughly 12 million passengers and 100,000 flights each day. In the U.S. there are roughly 160 airports which handle international flights. 

With incubation periods that can range from a couple of days to several weeks, anyone who is recently exposed could easily change planes and continents several times before ever they ever show signs of illness.

Previous failed attempts to prevent the spread of H1N1 pandemic flu and COVID illustrate just how difficult interdiction really is. 

• In 2010's Japan: Quarantine At Ports Ineffective Against Pandemic Flu, we looked at a study which found for every person identified, and quarantined, by port authorities - researchers estimated 14 others infected by the virus entered undetected.

• In April of 2012, in EID Journal: Airport Screening For Pandemic Flu In New Zealand, we looked at a study that found that the screening methods used at New Zealand’s airport were inadequate to slow the entry of the 2009 pandemic flu into their country, detecting less than 6% of those infected.

• And in late 2020, a CDC MMWR Risk Assessment and Management of COVID-19 Among Travelers Arriving at Designated U.S. Airports, January 17–September 13, 2020, found that `Symptom-based screening programs are ineffective because of the nonspecific clinical presentation of COVID-19 and asymptomatic cases.'

None of this is to say there is no value in trying to detect, and quarantine, potentially infected travelers coming from an outbreak region; only that we need to temper our expectations.

Surveillance can often identify acutely ill individuals when they are likely to be the most contagious so they can be promptly isolated, and it can provide important surveillance information. And it might even help slow the rate of entry of an emerging disease into a region, allowing additional time to mount public health interventions.

But as far as preventing an infectious disease like Ebola, MERS-CoV, or novel Flu from entering this - or any other country - airport screening is unlikely to provide much in the way of long-term protection. 

The best place to try to stop the next pandemic is not at the inbound passenger gate, but in the places around the world where they are most likely to emerge.

But in our increasingly chaotic and insular world, that goal seems less obtainable with every passing day.

UKHSA MERS-CoV Risk Assessment & Updates

 

#19,164

The month of May has already borne witness to a high-profile Andes Hantavirus outbreak aboard the m/v Hondius and a burgeoning Bundibugyo Ebolavirus outbreak in Central Africa, which makes bringing up MERS-CoV this morning almost feel like piling on.  

But, with the 2026 Hajj only a week away, and nearly 2 million religious pilgrims expected to visit holy sites in Saudi Arabia, the low (but non-zero) possibility of seeing one or more MERS-CoV cases returning from the region cannot be ignored.

The UK's latest MERS-CoV Risk assessment reads, in part:

Risk assessment

The number of reported human MERS-CoV cases per year globally, has fallen to the lowest level since 2014. The identification of 2 imported cases of MERS-CoV in France demonstrates that MERS continues to pose a risk to UK public health, particularly in those who have travelled to the Middle East.

In addition to PCR confirmed cases in the Middle East, there is serological evidence of MERS-CoV infection of camel-workers in Nigeria, Kenya and Morocco. There is therefore a very low risk of importation of MERS-CoV from occupationally exposed individuals from those African countries. It is imperative that health professionals remain vigilant for clinical presentations compatible with Middle East respiratory syndrome. Detailed case definitions and guidance on when to suspect MERS is given in the MERS-CoV: diagnosis and management of cases and contacts.

Today, the UKHSA has published (or updated) more than a half dozen additional documents pertaining to MERS-CoV and/or travel to the Middle East. 

UKHSA risk assessment of MERS-CoV Updated: 18 May 2026

MERS-CoV: risk assessment

Guidance on reducing the risk of getting MERS-CoV for UK residents and travellers to the Middle East.Updated: 18 May 2026 

MERS-CoV: minimum data set form for possible cases
Minimum data set form for possible cases of Middle East respiratory syndrome coronavirus (MERS-CoV).

MERS-CoV: diagnostic testing
Information on taking, submitting and processing clinical samples from patients suspected of having Middle East respiratory syndrome coronavirus (MERS-CoV). Updated: 18 May 2026

MERS-CoV: diagnosis and management of cases and contacts
This guidance is for healthcare professionals and health protection teams (HPTs) on identifying and managing cases of Middle East respiratory syndrome (MERS).Updated: 18 May 2026

MERS-CoV: background information
This guidance gives advice on the transmission, diagnosis, treatment and prevention of Middle East respiratory syndrome coronavirus (MERS-CoV) to the public.Updated: 18 May 2026

MERS-CoV: clinical management and guidance
Guidance on investigating Middle East respiratory syndrome coronavirus (MERS-CoV), public health management of suspected UK cases and advice to travellers.Updated: 18 May 2026

MERS-CoV: biological principles for the control of MERS-CoV
This guidance outlines the current knowledge and assumptions about the biology and transmission of Middle East respiratory syndrome coronavirus (MERS-CoV).Updated: 18 May 2026

MERS-CoV: travel from the Middle East advice sheet
Infographic with advice on Middle East respiratory syndrome coronavirus (MERS-CoV) for people travelling to the UK from the Middle East.Updated: 18 May 2026

MERS-CoV: travel from the Middle East advice sheet (HTML version) Updated: 18 May 2026

While the number of reported cases has declined over the past 6 years, we've seen several recent high-profile reports of spillovers, including France MOH: 2 Travelers Returning From Arabian Peninsula Diagnosed with MERS-CoV and WHO: Saudi Arabia Reports 9 New MERS-CoV Cases.

Not surprisingly, over the past year we've also seen a resurgence in MERS-CoV-related studies, including:

The Lancet: The Threat of Another Coronavirus Pandemic

Health Sci Rpts (Narrative Review): Pathogenicity and Potential Role of MERS-CoV in the Emergence of “Disease X”

IJID Editorial: Al-Tawfiq on Global Epidemiology and Public Health Challenges of Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

JEGH: Epidemiological Characteristics of MERS-CoV Human Cases, 2012- 2025

JEGH: Al-Tawfiq & Memish On Recurrent MERS-CoV Transmission in Saudi Arabia

As recently as last March - a WHO-authored commentary, published in Nature - warned that the MERS-CoV continues to circulate in dromedary camels in the Middle East, that it appears to maintain its virulence, and it remains a plausible pandemic threat.

I consider trying to predict the next big global health crisis a mug's game, since so many things could come at us out of left field with little or no warning.  

But recent studies suggest that the frequency, and impact, of pandemics are only expected to increase in the years ahead.

BMJ Global: Historical Trends Demonstrate a Pattern of Increasingly Frequent & Severe Zoonotic Spillover Events

PNAS Research: Intensity and Frequency of Extreme Novel Epidemics

So, while I can't tell you what type of emerging disease will spark the next pandemic - or when - it is all but guaranteed to happen again.  

The only question is; when that day comes, will we be ready?

Canada: PHAC Statement on `Presumed Positive' Hantavirus Case in Vancouver

#19,163

One of the m/v Hondius passengers, recently repatriated to Canada, has developed symptoms and has presumptively tested positive for the Hantavirus. Their spouse is also reportedly mildly symptomatic, and both have been hospitalized (along with a 3rd contact). 

The phrase `presumptive positive' simply means a local laboratory has obtained a positive result, confirmation of these results by the PHAC's National Microbiology Laboratory in Winnipeg will take a couple of days.

While concerning, known cases continue to be reported only among passengers and crew of the m/v Hondius.  Whether additional - `off-ship' infections - will emerge remains to be seen. 

Canada's PHAC released the following statement late Saturday afternoon.

Media update on Andes hantavirus situation

From: Public Health Agency of Canada
Statement

May 16, 2026 | Ottawa, ON

On May 16, 2026, the British Columbia Provincial Health Officer reported that one of the four high risk individuals who was self-isolating and being monitored for symptoms has tested presumptive positive for Andes hantavirus. The person was transported to hospital for assessment and care on May 14 along with their spouse who also has mild symptoms. The couple were passengers on the MV Hondius. Both will remain in isolation in hospital. Out of an abundance of caution, a third individual who was in secure lodging for isolation has been transferred to hospital for assessment and testing.

All infection prevention and control protocols are being followed, including the use of personal protective equipment by healthcare workers and personnel involved in the repatriation. Those involved in the repatriation are not considered at risk given the public health protective measures that were in place, in addition to the length of time between repatriation and the onset of symptoms.

Samples have arrived at the Public Health Agency of Canada’s National Microbiology Laboratory (NML) in Winnipeg for confirmatory testing. Results are expected in the next two days.

The Public Health Agency of Canada, the province of British Columbia, and local public health are working together to ensure all public health measures continue to be followed to protect the health of Canadians.

The overall risk to the general population in Canada from the Andes hantavirus outbreak linked to the MV Hondius cruise ship remains low at this time. But, given the severity of this virus, we are taking a precautionary approach to ensure Canadians are protected.

The Public Health Agency of Canada will continue to actively monitor the situation, provide guidance and support to provincial/territorial public health partners and share updates as needed.