Cholera is an illness caused by bacteria that can result in watery diarrhoea and vomiting. In healthy people, cholera can be asymptomatic or mild with diarrhoea being the only symptom. In severe cases however, the illness has a sudden onset with watery diarrhoea, nausea (feeling sick) and vomiting. If left untreated, this can lead to severe dehydration and can potentially lead to death within hours.
Dengue is a viral infection spread to people by infected mosquitoes. In most cases there are no symptoms, but the infection can occasionally develop into a more severe form. Dengue is widespread throughout the tropics and subtropics, where nearly 100 million cases are thought to occur every year.
Diphtheria is a serious infection that can be caused by different but related types of a bacterium. The infection typically affects the throat and tonsils, but it can also affect the skin if wounds or injuries are present. If the disease becomes very severe, the airways can become blocked.
Hepatitis A is a viral infection that affects the liver. It is rare in the UK and other developed countries, with most of the reported cases in these places occurring in travellers who have recently been to areas where the disease is more common. Hepatitis A can occur worldwide, but is most common in lower-income countries and regions with poor sanitation and hygiene. These include India, sub-Saharan and North Africa, parts of the Far East, South and Central America and the Middle East.
Hepatitis B is a viral infection of the liver transmitted by contact with the blood or body fluids of an infected person. It can be passed from mother to baby, through a puncture to the skin, when blood splashes into the eyes, nose or mouth, or through unprotected sex. Worldwide more than 240 million people are thought to be infected with hepatitis B. Around 780,000 people die each year as a result of hepatitis B infection.
Influenza, more commonly known as the flu, is an infectious disease caused by a virus that affects the nose, throat, airways and lungs. The infection is spread from person to person through the air when infected people cough or sneeze, meaning it spreads quickly in crowded and enclosed areas. You can also catch the flu from touching things which are carrying the virus, such as furniture that an infected person has sneezed on, and then touching your nose or mouth.
Japanese encephalitis is a viral infection of the brain, which is spread from animals and birds to humans by the bite of an infected mosquito. It is found in parts of Asia, the Indian subcontinent and the Pacific rim, especially in rural areas where rice paddies and pig farming are common. In affected countries, around 70,000 cases are thought to occur every year.
Malaria is a potentially serious parasitic infection, spread by the bite of an infected mosquito. It occurs throughout tropical and subtropical areas, including parts of Africa, Asia, Central and South America, the Caribbean, the Middle East and Oceania. Worldwide, nearly 200 million cases of malaria are thought to occur every year, with around 1,500 in travellers returning to, or entering, the UK. Malaria can be prevented, and although it can be fatal, it can be cured if it is diagnosed and treated quickly.
Measles is a highly infectious disease caused by a virus. Worldwide, it causes thousands of deaths per year, and can be very serious, particularly in children. Once somebody has been infected with measles, no specific treatments are available and instead they must wait for the virus to disappear naturally.
Meningococcal disease is a rare infection caused by several different types of a bacterium called the meningococcus.1 The disease can present in several ways, but most commonly as meningitis or septicaemia (also known as blood poisoning). The disease can be found across the world, although the highest numbers of infections are seen in sub-Saharan Africa in the area known as the 'meningitis belt', which stretches from Senegal to Ethiopia.
Polio is an infection caused by a virus that is usually transmitted via water contaminated with the faeces of someone with the disease or through direct contact with an infected person. Most people with the disease do not have any symptoms, but can still pass on the virus to other people. When serious, it can cause meningitis or paralysis, although this is very rare.
Rabies is a disease caused by a virus that is passed on to humans by mammals. The virus is introduced from the animal’s saliva via a bite or scratch, and is normally caught from dogs, but can also be spread by bats, monkeys or cats. It can also be spread when saliva from an infected animal comes into contact with broken skin, or the eyes, nose or mouth. Rabies affects the central nervous system, and once symptoms develop, is almost always fatal.
Schistosomiasis is an infection caused by a parasite that is most commonly found in tropical regions. The infection is caused by the larval forms of parasitic worms, which can penetrate the skin of people swimming or bathing in contaminated water.2 Once through the skin, the larvae can move to the liver and can begin the next stage of their lifecycle.1 The parasites' eggs are transmitted in the urine and faeces of infected people.
Tetanus is a disease caused by a bacterium which is found in soil and some animal faeces. The infection occurs when bacteria are introduced into a wound, where they produce a harmful toxin (poison). Tetanus is a serious disease that needs intensive medical support.
Tick-borne encephalitis (TBE) is a viral infection that affects the central nervous system (brain and spinal cord) causing a spectrum of disease ranging from a mild illness to a more severe, life-threatening illness. It is usually transmitted through the bite of an infected tick.
Tuberculosis, commonly known as TB, is a bacterial infection. It can affect any organ of the body, but most often affects the lungs. Tuberculosis is still common today, with millions of new infections reported globally each year.
Typhoid fever is an infection caused by bacteria found in food and water that has been contaminated with human urine and faeces. The disease occurs worldwide, but is most common in lower-income countries and regions where sanitation is poor and clean water is harder to find. These include parts of Asia, Africa and Central and South America.
Yellow fever is a viral infection spread between monkeys and humans by the bite of an infected mosquito. It is found in two so-called yellow fever zones–in tropical parts of sub-Saharan Africa and South America. Worldwide, around 200,000 cases of yellow fever are thought to occur every year, mostly in Africa, leading to about 30,000 deaths.
Zika virus is a viral infection that is spread by the bite of an infected mosquito. It usually leads to very mild symptoms, but in rare cases may cause birth defects and problems with the central nervous system. The virus is found in parts of Africa, Asia and the Pacific Islands, has recently been reported in Central and South America, India and the Caribbean.