The UK Health Security Agency (UKHSA) list contains 15 of the most frightening infectious diseases.
These are known as high consequence infectious diseases (HCID).
Getting a pathogen into this category typically has a high mortality rate and requires an officially organized response to ensure it is managed effectively, as the symptoms are often difficult to spot.
The data was created to enable health professionals to assess infection risk for each country.
But it is also publicly available for anyone to access online.
Crimean-Congo hemorrhagic fever (CCHF)
Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease.
It causes symptoms such as high fever, muscle aches, dizziness, abnormal sensitivity to light, abdominal pain, and vomiting.
Later, sharp mood swings may occur and the patient may become confused and aggressive.
There is no vaccine or specific antiviral that works against CCHF. But a broad-spectrum antiviral called ribavirin can be given to patients to prevent serious illness.
CCHF has been found among ticks in Africa, Asia, the Middle East and Eastern Europe, and Southwestern Europe.
It kills up to 40 percent of anyone who becomes infected, according to the World Health Organization (WHO).
Black Death
It may be infamous for killing millions of people in Europe during the Middle Ages.
But the plague is still a threat in parts of the world, including parts of Africa, Asia, South America and even the US.
Humans usually become infected after being bitten by fleas that lurk on rodents.
However, the disease can also spread by inhaling respiratory droplets from people infected with a type of plague called pneumonia.
The bubonic plague, responsible for the Black Death, causes the telltale signs of swollen nodes. These can then turn into open, pus-filled sores.
Other symptoms include shortness of breath, chest pain, and cough.
Between 30 and 100 percent of people with confirmed infections die if they don’t receive treatment.
Antibiotics are effective against plague if patients are diagnosed early.
The WHO recommends that only people at high risk of exposure to plague, such as laboratory and hospital workers, receive a vaccine against it.
Marburg
The Marburg virus belongs to the filovirus family and is therefore a cousin of Ebola.
It was first discovered in 1967 after an outbreak in Marburg, Germany, among workers exposed to African green monkeys.
Fruit bats are believed to be the natural hosts of the disease, which causes sporadic outbreaks in Africa.
It spreads among humans through direct contact with infected people’s bodily fluids, surfaces, and materials.
Symptoms come on abruptly and include severe headache, fever, diarrhea, stomach pain and vomiting. They are getting more and more serious.
Infected patients may become ‘ghostly’ and often develop deep-set eyes and expressionless faces.
This is usually accompanied by bleeding from multiple orifices, including the nose, gums, eyes, and vagina.
The Marburg virus has a mortality rate of up to 88 percent, data suggests.
There are no proven treatments or vaccines for Marburg.
Junin virus
The virus is found in the central parts of the Pampas, vast plains stretching from Argentina’s Atlantic coast to the Andes.
Data suggests that the hemorrhagic fever kills up to 30 percent of patients who go untreated.
Symptoms include chills, headache, and pain.
Rodents are natural hosts of the virus. Human-to-human transmission is rare, experts say.
Andean virus
The Andean virus – found in rodents in South America – is a hantavirus.
While it is usually spread through contact with infected rodents or their feces, it can be passed on through close human contact.
Early symptoms include headache, fever, and muscle aches, which means it can be very similar to the flu.
According to the UKHSA, the fatality rate is close to 50 percent.
bird flu
Many scientists think bird flu will be the trigger of the next pandemic.
Four strains of bird flu have caused concern in humans: H5N1, H7N9, H5N6 and H5N8.
Although rare, avian flu can spread to humans by touching infected birds, touching feces or litter, killing or preparing infected poultry for cooking.
H5N1 – the avian flu strain behind the current outbreak sweeping the world, believed to be the largest ever – is not easily transmitted between humans.
But mutations in the virus that facilitate mammal-to-mammal transmission could change that, some experts fear.
There are fewer than 900 human cases of H5N1 worldwide, which kills nearly 50 percent of those it affects.
Bird flu symptoms in humans can include a very high temperature or feeling hot or shivering, muscle aches, headache, and coughing or shortness of breath.
Nipah virus
Nipah is a type of henipavirus, which is naturally retained in fruit bats.
The virus is usually transmitted to humans through direct contact with infected animals, usually pigs and bats.
But human-to-human transmission can occur.
Outbreaks occur almost annually in parts of Asia, mainly Bangladesh and India, the US CDC says.
Symptoms, such as fever, headache and drowsiness, can appear between five and 14 days after infection and can last up to two weeks.
Eventually, patients may fall into a coma or have difficulty breathing.
The virus is thought to be fatal in 75 percent of cases.
There is no vaccine or cure, but patients can receive supportive treatment to relieve symptoms.
Lassa fever
According to the World Health Organization, 80 percent of people who become infected develop no symptoms.
But the virus has a mortality rate of about 1 percent.
According to WHO, Lassa fever is endemic in Nigeria and several other countries on the west coast of Africa, including Liberia and Guinea.
Symptoms begin with a headache, sore throat, and vomiting, but it can cause bleeding from the mouth, nose, or vagina.
However, they gradually progress to shock, seizures, tremors, disorientation and comas without immediate treatment.
A quarter of patients will also experience temporary deafness that will eventually return, medical literature states.
Pregnant women who contract the disease late in pregnancy have an 80 percent chance of losing their child or dying.
It can be spread by rats or from person to person through exposure to bodily fluids of someone who is infected.
Ebola
Ebola is an often fatal viral hemorrhagic fever named after a river in the Democratic Republic of the Congo (DRC) where it was discovered in 1976.
The virus is mainly transmitted through exposure to bodily fluids, with the main symptoms being fever, vomiting, bleeding and diarrhea.
It occurs naturally in fruit bats, monkeys and porcupines living in the rainforest, and can also be transmitted by eating uncooked bushmeat.
Ebola outbreaks are difficult to contain, especially in urban environments.
People who are infected do not become contagious until symptoms appear, that is, after an incubation period of two to 21 days.
Ebola has a mortality rate of about 50 percent, the WHO says.
Monkeypox
Monkeypox is a rare viral infection that people usually pick up in the tropical regions of West and Central Africa.
It is usually spread through direct contact with animals such as squirrels, which are known to carry the virus.
However, it can also be transmitted through very close contact with an infected person.
Monkeypox was first discovered in 1958 when an outbreak of a smallpox-like disease occurred in research monkeys.
Monkeypox is usually mild and most patients recover within a few weeks without treatment. Still, the disease can be fatal.
Common symptoms are skin rashes or mucosal lesions, accompanied by fever, headache, muscle pain, back pain and fatigue.
Severe Acute Respiratory Syndrome (SARS)
SARS is Covid’s cousin and causes similar flu-like symptoms.
It infected 8,000 people and killed nearly 800 in an outbreak in Asia in 2003.
However, SARS is more deadly than Covid.
Data suggests it kills about one in 10 people, compared to less than one in 100 from Covid.
The airborne virus can spread through tiny droplets of saliva, in a similar way to the common cold and flu.
Middle East respiratory syndrome coronavirus (MERS-CoV)
Middle East respiratory syndrome coronavirus (MERS), also known as camel flu, is a rare but serious respiratory illness.
People can get MERS from infected animals — though doctors say camels are the main source of the virus in the Middle East. The virus was first detected in 2012.
It can also be transmitted through the cough drops of an infected person, but this is rare.
The symptoms are fever, cough, difficulty breathing, diarrhea and vomiting.
There is no specific treatment for the disease, so doctors try to relieve a patient’s symptoms.
About 35 percent of those who get MERS die as a result.
Severe fever with thrombocytopenia syndrome (SFTS)
The syndrome is caused by a tick-borne virus.
However, human-to-human transmission of SFTSV can occur.
Human cases have been identified in China, as well as Japan, South Korea and Taiwan.
The virus starts with flu-like symptoms, but can progress quickly.
Patients suffer from thrombocytopenia – a reduction in the number of platelets in their blood, which reduces its ability to clot.
Data suggests that SFTSV has a mortality rate of about 5 percent.
Lujo virus
The Lujo virus has a mortality rate of about 80 percent, it is estimated.
Humans can become infected by handling rodents that carry the disease.
However, human-to-human transmission has been observed.
Symptoms include a rash on the face and body, swelling of the face and neck, sore throat, and diarrhea.
In fatal cases, patients may improve somewhat before suddenly getting worse.