Fewer people are infected by dreaded tropical diseases



For many years there has been a list of so-called “translated” tropical diseases in the drawers of the World Health Organization WHO. It may sound harmless, but the diseases have not been overlooked because they are not harmful. Not at all. On the contrary, there are some of the world’s worst infectious diseases, reminiscent of something we usually only see in horror films. For example, elephantiasis, where parasites block the lymphatic system, so that arms and legs swell to a grotesque size. Leprosy, which leaves its victims disfigured and outcast. River blindness, where the mark burrows into the eyes and makes the infected person permanently blind. Buruli ulcers, where flesh-eating bacteria slowly eat away at the skin and muscles. Fungal infections, which cover the body with oozing boils. Altogether there are twenty diseases on the black list. But if the diseases are so serious, why have they ended up being overlooked? – There has been a lack of money for the development of medicine against these diseases. And that is because the pharmaceutical companies have not been able to make money from them, says Marie Helleberg, Ph.D. with major in tropical medicine. Today, she is a senior physician at Rigshospitalet (in Copenhagen), and she has previously lived and conducted research in a number of developing countries, including Guinea-Bissau, Ghana, Kenya and on the Thai-Burmese border. The world has begun to do something about the problem Despite years of lack of money, the neglected tropical diseases are now no longer as neglected as they used to be. The world’s countries have become more focused on the problems, and in many places the number of cases of the diseases is falling, thanks to renewed efforts against them. This is shown by a new report from the WHO. The effort has meant that the number of people who need treatment for one or more of the diseases on the list has fallen by a quarter over the past ten years. And although the shutdown in connection with the corona pandemic meant a setback to the treatment of many diseases, the number of people in need of treatment for the translated diseases still fell by 80 million in just one year, between 2020 and 2021. It is one of the biggest declines in recent years couple of years, and a large part of the progress is due to the fact that significantly fewer children in India have now used preventive deworming, the report states. – It is very important to focus on these translated diseases. Because even if they are “just” common worm infections, they can affect people to a great extent. For example, children with long-term worm infections can become anemic, so that they become tired and struggle to concentrate and follow along at school, says Marie Helleberg. Also progress in some of the hardest hit countries Although the translated number of cases of the tropical diseases is falling overall, there is a big difference in how each individual disease is doing, as they are very different and are found in a number of countries. Some countries are making great progress, while others are lagging far behind. In Africa, there has actually been an increase in the number of people infected in the last couple of years, while Latin America remains unchanged. But even in the worst areas there are several concrete bright spots. For example, DR Congo eradicated the guinea fowl last year. And Rwanda, Uganda and Equatorial Guinea put an end to sleeping sickness in the same year, which, despite its sleep-inducing name, is deadly and difficult to treat. – We have a remedy for sleeping sickness, but the medicine itself is based on arsenic and is so toxic that it kills 5-10 per cent of the patients. But now there is a new medicine on the way, and we hope that it will prove to be just as effective against sleeping sickness, but far more gentle on the patient, says Marie Helleberg. Man’s worst enemies Many of the translated tropical diseases are caused by parasites that are transmitted to humans via other animals. For example, the parasites can be spread by flies or snails that live in water. But dogs are also among man’s worst enemies. Both because dog faeces can easily spread parasite eggs, and because bites from wild dogs cause rabies, which is one hundred percent fatal if you do not get vaccinated before the disease breaks out. Rabies is not a small problem. Every year, 29 million people receive emergency preventive treatment against rabies after being bitten by dogs. But around 59,000 people do not have enough, WHO estimates. – There is no treatment once the virus has time to spread from the bite wound and reaches the brain. In Kenya, we had a seven-year-old boy with rabies as a patient, but he arrived at the hospital too late. We could do nothing but try to alleviate the symptoms of the disease before he died, says Marie Helleberg. She explains that the only thing that actually works against rabies in a country is to reduce the number of wild street dogs, or alternatively to vaccinate them all. Vaccines on the way to making a big difference Although far from all vaccines provide 100 percent protection, they are still one of the most effective means of combating diseases both in and outside the tropics. When a vaccine has finally been developed against a disease where previously none existed, it can make a huge difference. For example, the crippling childhood disease polio is now nearly eradicated, where it once left hundreds of thousands of people permanently paralyzed each year. This is because a vaccine was developed in the 1930s, and that many millions of doses have subsequently been given to children all over the world. Polio is not on the list of translated diseases, but there is, for example, dengue fever, which is still ravaging. There is still hope that this disease can be eradicated, says Marie Helleberg. – Dengue fever is another disease that has increased sharply in the last couple of years. And it can be fatal for some. The positive thing is that some vaccines have now been developed against the disease, and I really believe that they will make a difference, she expects.



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