Travellers' diarrhoea

There are almost as many names for this as there are travellers' tales on the subject. Firstly, do resist the temptation to reach for the medical kit as soon as your stomach turns a little fluid. Most cases of travellers' diarrhoea will resolve themselves within 24–48 hours with no treatment at all. To speed up this process of acclimatisation, eat well but simply: avoid fats in favour of starches, and keep your fluid intake high. Bananas and papaya fruit are often claimed to be helpful. If you urgently need to stop the symptoms, for a long journey for example, then Lomotil, Imodium or another of the commercial anti-diarrhoea preparations will do the trick. They stop the symptoms, by paralysing the bowel, but will not cure the problem. (If you do decide to take these, they are best taken in conjunction with an antibiotic like ciprofloxacin – 500mg twice a day for three days.)

When severe diarrhoea gets continually worse, or the stools contain blood, pus or slime, or it lasts for more than three or four days, you must seek medical advice. There are as many possible treatments as there are causes, and a proper diagnosis involves microscopic analysis of a stool sample, so go straight to your nearest hospital. The most important thing, especially in Zambia's hot climate, is to keep your fluid intake up.

The body's absorption of fluids is assisted by adding small amounts of dissolved sugars, salts and minerals to the water. Sachets of oral rehydration salts give the perfect biochemical mix you need to replace what is pouring out of your bottom but they do not taste so nice. Any dilute mixture of sugar and salt in water will do you good so, if you like Coke or orange squash, drink that with a three-finger pinch of salt added to each glass. The ideal ratio is eight level teaspoons of sugar and one level teaspoon of salt dissolved in one litre of water. Palm syrup or honey make good substitutes for sugar, and including fresh citrus juice will not only improve the taste of these solutions, but also add valuable potassium.

Drink two large glasses after every bowel action, and more if you are thirsty. If you are not eating you need to drink three litres a day plus whatever you are sweating and the equivalent of what's going into the toilet. If you feel like eating, take a bland diet; heavy greasy foods will give you cramps.

If you are likely to be more than a few days from qualified medical help, then come equipped with a good health manual and the selection of antibiotics which it recommends. Bugs, Bites & Bowels by Dr Jane Wilson-Howarth is excellent for this purpose.

Malaria

You can still catch malaria even if you are taking anti-malarial drugs. Classic symptoms include headaches, chills and sweating, abdominal pains, aching joints and fever – some or all of which may come in waves. It varies tremendously, but often starts like a bad case of flu. If anything like this happens, you should suspect malaria and seek immediate medical help. A definite diagnosis of malaria is normally only possible by examining a blood sample under the microscope. It is best to get the problem properly diagnosed if possible, so don't treat yourself if you can easily reach a hospital.

If (and only if) medical help is unavailable, then self-treatment is fairly safe, except for people who are pregnant or under twelve years of age. In Zambia you will often be able to get experienced local advice to tell you which will be the most effective.

If you plan to be off the beaten track it is wise to consider taking a malaria treatment with you. However, always discuss this with a specialist doctor who can give the most up to date advice.

Quinine is very strong, but often proves to be an effective last defence against malaria. Include it in your medical kit, as occasionally rural clinics will have the expertise to treat you, but not the drugs. Treatment consists of taking two quinine tablets (600mg) every eight hours for up to seven days, until the fever abates. Quinine's side effects are disorientating and unpleasant (nausea and a constant buzzing in the ears), so administering this whilst on your own is not advisable. You should never wait to complete the course before seeking medical advice. Other effective treatments include Malarone (four tablets taken at the same time each day for three days) and Riamet, which involves a more complicated regime of taking 24 tablets over 60 hours. Halfan is no longer considered a safe treatment and should never be taken.

Sexually transmitted diseases

AIDS is spread in exactly the same way in Africa as it is at home, through body secretions, blood, and blood products. The same goes for the dangerous Hepatitis B. Both can be spread through sex.

Remember the risks of sexually transmitted disease are high, whether you sleep with fellow travellers or with locals. About 40% of HIV infections in British people are acquired abroad. Using condoms or femidoms will reduce this risk considerably, but not eliminate it. Conservative estimates suggest HIV infection rates in Zambia of 30%, although the infection rate of high-risk groups, like prostitutes, is far greater. If you notice any genital ulcers or discharge get treatment promptly.

Hepatitis
This is a group of viral diseases that generally start with Coca-Cola-coloured urine and light-coloured stools. It progresses to fevers, weakness, jaundice (yellow skin and eyeballs) and abdominal pains caused by a severe inflammation of the liver. There are several forms, of which the two most common are typical of the rest: Hepatitis A (or infectious hepatitis) and hepatitis B (or serum hepatitis).

Hepatitis A, and the newly discovered hepatitis E, are spread by the faecal-oral route, that is by ingesting food or drink contaminated by excrement. They are avoided in the same ways you normally avoid stomach problems: by careful preparation of food and by only drinking clean water. There are now excellent vaccines against hepatitis A, which consist of two doses given about a year apart and provide at least ten years protection – definitely worth getting before you travel.

In contrast, the more serious but rarer hepatitis B is spread in the same way as AIDS (by blood or body secretions), and is avoided the same way as one avoids AIDS. There is a vaccine that protects against hepatitis B, which you should definitely get if you are working in a medical setting or with local children and should consider for other trips of four weeks or more.

There are no cures for hepatitis, but with lots of bed rest and a good low-fat, no-alcohol diet most people recover within six months. If you are unlucky enough to contract hepatitis of any form, use your travel insurance to fly straight home.

Rabies

Rabies is contracted when broken skin comes into contact with saliva from an infected animal, eg: from a bite, a scratch or a lick over broken skin. The disease is always fatal if contracted, but fortunately there are excellent post-exposure vaccines providing they are available. It is for this reason that taking pre-exposure doses of rabies vaccine are highly recommended, especially if you are going to be off the beaten track, spending more than four weeks in Zambia or are working with animals. Even if you have been immunised, it is standard practice to treat all cases of possible exposure with two post-exposure jabs, so whatever your vaccine status go immediately to medical help if you think you have been exposed.

Rabies is rarely a problem for visitors, but the small risk is further minimised by avoiding small mammals. This is especially true of any animals acting strangely. Both mad dogs in town and friendly jackals in the bush should be given a very wide berth.

If you are bitten, clean and disinfect the wound thoroughly by scrubbing it with soap under running water for five minutes, and then flood it with local spirit or diluted iodine. Then seek medical advice for the reasons stated above.

The incubation period for rabies is the time taken for the virus to travel from the area of bite to the brain. This varies with the distance of the bite from the head – from a week or so, to many months. If the bites are further from the brain the incubation period is longer and you probably have more time. However, there is no room for complacency as the risk of developing rabies also depends upon how much virus the animal is carrying – something you can't tell just by looking at the culprit!. Make sure you get the injections as soon as possible, even if you are a very long way from civilisation.

Never say that it is too late to bother. The later stages of the disease are horrendous – spasms, personality changes and hydrophobia (fear of water). Death from rabies is probably one of the worst ways to go.

Bilharzia

Bilharzia is an insidious disease, contracted by coming into contact with infected water. It is caused by an infestation of parasitic worms which damage the bladder and/or intestine. Often the parasites are present in the local population who have built up a measure of immunity over time, but the visitor who becomes infected may develop a severe fever for weeks afterwards. A common indication of an infection is a localised itchy rash – where the parasites have burrowed through the skin – and symptoms of a more advanced infection will probably include passing bloody urine. Bilharzia is readily treated by medication, and only serious if it remains undetected (the symptoms may be confused with malaria) and untreated.

The life-cycle of the parasites starts when they are urinated into a body of water. Here they infect particular species of water-snails. They grow, multiply, and finally become free-swimming. Then they leave the snails to look for a human, or primate, host. After burrowing through the skin of someone coming into contact with the water, they migrate to the person's bladder or intestine where they remain – producing a large number of eggs which are passed every day in the urine, so continuing the cycle.

The only way to avoid bilharzia infection completely is to stay away from any bodies of fresh water. Obviously this is restrictive, and would make your trip less enjoyable. More pragmatic advice is to avoid slow-moving or sluggish water, and ask local opinion on the bilharzia risk, as not all water is infected. Generally these snails do not inhabit fast-flowing water, and hence rivers are free from infection. However, dams and standing water, especially in populated areas, are usually heavily infected. If you think you have been infected, don't worry about it – just get a test done on your return.

Sleeping sickness or trypanosomiasis

This is really a cattle disease, which is occasionally caught by people. It is spread by bites from the distinctive tsetse fly – which is slightly larger than a housefly, and has pointed mouth-parts designed for sucking blood. These flies are easily spotted as they bite during the day, and have distinctive wings that cross into a scissors shape when they are resting.

Prevention is easier than cure, so avoid being bitten by covering up. Chemical insect repellents are also helpful. Dark colours, especially blue, are favoured by the flies, so avoid wearing these if possible.

Tsetse bites are nasty, so expect them to swell up and turn red – that is a normal allergic reaction to any bite. The vast majority of tsetse bites will just do this. However, if the bite develops into a boil-like swelling after five or more days, and a fever two or three weeks later, then seek immediate medical treatment to avert permanent damage to your central nervous system. The name 'sleeping sickness' refers to a daytime drowsiness which is characteristic of the later stages of the disease.

Because this is a rare complaint, most doctors in the West are unfamiliar with it. If you think that you may have been infected – draw their attention to the possibility. Treatment is straightforward, once a correct diagnosis has been made.

Some Africans view the fly positively, referring to it as a guardian of wild Africa, because fear of the disease's effect on cattle has prevented farming, and hence settlement, encroaching on many areas of wild bush. In recent years the tsetse fly has been subject to relentless spraying programmes in much of the sub-continent, designed to remove the last natural barrier to cattle farming. Then material screens, impregnated with a chemical attractant derived from cattle and an insecticide, are hung in shady areas under trees in order to attract and kill any remaining flies.

Tsetse flies are common in many areas of Zambia – including most of the national parks – although cases of sleeping sickness are exceedingly rare.

Returning home

Many tropical diseases have a long incubation period, and it is possible to develop symptoms weeks after returning home (this is why it is important to keep taking anti-malaria prophylaxis for the prescribed time after you leave a malarial zone). If you do become ill after you return home, be certain to tell your doctor where you have been. Alert him/her to any diseases that you may have been exposed to. Several people die from malaria in the UK every year because victims do not seek medical help promptly or their doctors are not familiar with the symptoms, and so are slow to make a correct diagnosis. Milder forms of malaria may take up to a year to reveal themselves, but serious (falciparum) malaria will become apparent within four months.

If problems persist, get a check-up at one of the hospitals that specialise in tropical diseases. Note that to visit such a hospital in the UK, you need a letter of referral from your doctor.

For further advice or help in the UK, ask your local doctor to refer you to the London Hospital for Tropical Diseases, 4 St Pancras Way, London NW1 (tel: 020 7387 4411).