The threat of disease now looms large in Haiti

Good sanitation and clean drinking water are scarce in Haiti at the best of times. In these worst of times, structural damage to water and sewerage courses, along with cramped living conditions in camps, will inevitably lead to faecal contamination of drinking water. Epidemics of typhoid, which kills 20 per cent of those infected, cholera and dysentery, which cause severe diarrhoea – frequently lethal when drinking water is scarce – and hepatitis A, a viral liver disease that can have prolonged effects, are highly likely. Top priority for disaster relief is the provision of a clean water supply which will limit these infections. They are also preventable by vaccination and treatable with antibiotics – if the medicines can get to where they are needed in time.

While the sight of dead bodies littering the streets is traumatic, corpses are very bad at spreading infectious diseases. Rotting flesh smells terrible, but the bacteria that make this smell do not cause disease. It is now accepted that spending lots of time spraying corpses with disinfectant in the initial phases of a relief operation is not time well spent.

Infant mortality in Haiti is the highest in the Western hemisphere. Approximately 15 per cent of children die by the age of five, almost all because of infectious diseases. Infections such as streptococcal pneumonia and infant tetanus are already rife, and dust stirred up by rescue and rebuilding work will make them even more problematic. It is essential that babies and young children be given access to antibiotics to treat these killer diseases. Haitian dust also contains another killer: anthrax.

In March 2009, Unicef and the World Health Organisation launched a further vaccination drive, this time to immunise one million Haitian mothers and children against measles, mumps, rubella, polio, diphtheria, whooping cough and tetanus – a decision that may well pay dividends over the coming weeks as people cram together in camps. However, only about half of the population is immunised, so vaccination of the remaining children against these serious diseases is important to prevent epidemics.

Malaria is endemic in Haiti and other mosquito-borne protozoal diseases such as dengue fever are also common. With buildings destroyed, people spending nights out in the open are at much greater risk of being bitten by mosquitoes, so the provision of shelter, mosquito nets and anti-malarial drugs will be very important in the coming weeks.

Haiti has the highest HIV infection rate of any country outside Africa – about 5 per cent of the population – and Aids is the most common cause of adult death in Haiti. Its frequent bedfellow is TB, which kills thousands each year. Now that the healthcare system has totally collapsed and camps are filling up with people, TB may spread and leave a time bomb of chronic disease for the future.

Dr Matthew B Avison is senior lecturer in microbiology, University of Bristol