Several different viruses cause hepatitis; they differ in the way that they are transmitted. The symptoms in all forms of the illness include fever, chills, headache, fatigue, feelings of weakness and aches and pains, followed by loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-coloured faeces, jaundiced (yellow) skin and yellowing of the whites of the eyes.
There are 6 known types of viral hepatitis: A, B, C, D, E and G. G is not dangerous. A and E are passed on by the fecal-oral route of transmission; there is a vaccine. Seek medical advice, but there is not much you can do apart from resting, drinking lots of fluids, eating lightly and avoiding fatty foods. A and E cause an acute illness, but you will recover fully from it.
B and D are passed on via blood, saliva, semen and vaginal fluids. They can be passed on by close contact, sexual contact, and blood-to-blood contact. The symptoms of hepatitis B may be more severe than type A and the disease can lead to long-term problems such as chronic liver damage, liver cancer or a long-term carrier state. There is a vaccine.
Hepatitis C is only passed on from blood-to-blood contact. There is no vaccine.
This diarrhoeal disease can cause rapid dehydration and death. Cholera is caused by a bacteria, Vibrio cholerae. It's transmitted from person to person by direct contact (often via healthy carriers of the disease) or via contaminated food and water. It can be spread by seafood, including crustaceans and shellfish, which get infected via sewage.
Cholera exists where standards of environmental and personal hygiene are low. Every so often there are massive epidemics, usually due to contaminated water in conditions where there is a breakdown of the normal infrastructure.
The time between becoming infected and symptoms appearing is usually short, between one and five days. The diarrhoea starts suddenly, and pours out of you. It's characteristically described as 'ricewater' diarrhoea because it is watery and flecked with white mucus. Vomiting and muscle cramps are usual, but fever is rare. In its most serious form, it causes a massive outpouring of fluid (up to 20L a day). This is the worst case scenario - only about one in 10 sufferers get this severe form.
It's a self-limiting illness, meaning that if you don't succumb to dehydration, it will end in about a week without any treatment.
You should seek medical help urgently; in the meantime, start re-hydration therapy with oral re-hydration salts. You may need antibiotic treatment with tetracycline, but fluid replacement is the single most important treatment strategy in cholera.
Prevention is by taking basic food and water precautions, avoiding seafood and having scrupulous personal hygiene. The currently available vaccine is not thought worthwhile as it provides only limited protection for a short time.
Vaccination against this serious bacterial disease is very effective, so you don't need to worry if you've been properly immunised against it. It mainly affects children and causes a cold-like illness that is associated with a severe sore throat. A thick white membrane forms at the back of the throat which can suffocate you, but what makes this a really nasty disease is that the diphtheria bug produces a very powerful poison which can cause paralysis and affect the heart. Otherwise healthy people can carry the bug in their throats, and it's transmitted by sneezing and coughing. It can also cause a skin ulcer known as a veldt sore. Vaccination protects against this form too. Treatment is with penicillin and a diphtheria antitoxin, if necessary.