Tropical diseases threaten 1.6 billion people

In this context, the World Health Organization has defined 25 diseases caused by bacteria, viruses, parasites, fungi or toxins. This includes many diseases that have been known for decades, such as leprosy, sleeping sickness and schistosomiasis. They have one thing in common: they all have far-reaching health, social and financial consequences for patients.

They reinforce the vicious circle of poverty, poor education, little to no income, disease and disability, according to the specialized organization for people with disabilities ‘Light for the World’ next Tuesday on the day of neglected tropical diseases. In addition to his or her health problems, people who have leprosy are socially stigmatized and receive lower or no income.

Rapid spread
Tropical diseases spread particularly quickly in areas with poor infrastructure, such as poor rural areas, conflict zones and areas after natural disasters. If hygiene is poor and running water is not available, trachoma, a bacterial eye disease, leprosy or sleeping sickness quickly become a major problem.

Setbacks caused by the corona pandemic
According to ‘Light for the World’, the WHO has set itself the goal of eradicating neglected tropical diseases by 2030. This goal has become further away after setbacks, especially as a result of the corona pandemic. Yet there is progress: in 2010, for example, 2.2 billion people were threatened by tropical diseases, but the current figure is 1.6 billion. By the end of last year, at least fifty countries had eliminated at least one tropical disease. By 2030, at least one tropical disease must be eradicated from 100 countries.

The details of the diseases can be found in the list below.

Buruli ulcer: an infectious disease of the skin and soft tissues with the formation of sometimes extensive ulcers. The pathogen is Mycobacterium ulcerans. The disease can lead to severe disfigurement, but can also heal on its own after months or years. The disease is especially widespread in West, Central and East Africa among rural populations near bodies of water and wetlands.

Chagas disease: is caused by the protozoan Trypanosoma cruzi and is transmitted through the feces of blood-sucking predatory bugs. The disease is particularly widespread in Central and South America, but in Bolivia it is estimated that it could affect a quarter of the population. It occurs in four stages in humans, becomes chronic and, if left untreated, can lead to death in ten percent of those affected.

Chromoblastomykosis: a fungal infection that mainly affects the limbs and often remains chronic. Causes small nodular ulcers and is often resistant to treatment. Mainly found in tropical and subtropical areas.

Denguefieber: is caused by a virus transmitted by mosquitoes. Endemic to tropical and subtropical regions; approximately half of the world’s population lives in dengue endemic areas. 80 percent of infections have no symptoms, the remaining 20 percent usually have mild to moderate symptoms. Severe cases are rare and, if they do occur, usually only after a second infection. In severe cases, hemorrhagic dengue fever can occur; the mortality rate for these severe cases is one to five percent, but can also be as high as 15 percent in individual epidemics. A vaccination has recently become available.

Dracunculiasis or Dracontiasis: a serious parasitosis caused by the medina worm. The infection mainly occurs in the dry season, when there is no regulated drinking water supply and the population resorts to fetching water. The larvae of the medina worm reach humans via small copepods, where they are released into the small intestine. They burrow into the abdominal or chest muscles, where they mate. The male dies and the female grows to a height of up to one meter. The disease mainly occurs in the East. There is no drug treatment, but the worm can be removed surgically. After about a year and two to three weeks of release, the larva dies and the ulcer it caused usually heals.

Echinococcosis: This also applies to tapeworm infections.

Food-borne bones: especially widespread in East Asia and South America. Transmitted by eating raw fish and shellfish or vegetables that contain tail fins. For example, they cause serious lung and liver diseases.

Sleeping sickness (African trypanosomiasis): The disease is endemic to sub-Saharan Africa and is caused by human-pathogenic protozoa. They are transmitted by the tsetse fly when it bites. If left untreated, the disease leads to death.

Leishmaniasis: an infectious disease caused by parasites that mainly occurs in East Africa, but also in Colombia and Peru and is transmitted by sand flies. There are many clinical pictures. Internal leishmaniasis is particularly dangerous and is fatal in about 95 percent of cases without treatment.

Leprosy: is still a serious problem in many countries in the global south, while it has been virtually eliminated in countries with functioning healthcare systems. It is caused by Mycobacterium leprae and is transmitted via droplet infection. However, leprosy is only mildly contagious and is considered curable.

Lymphatic filariasis: an infection with parasitic roundworms. It is one of the most common neglected tropical diseases and manifests itself after several years in the development of elephantiasis, especially on the legs.

I have: is mainly caused by fungi, but also by bacteria that end up in a wound on the skin. Mainly occurs in the tropics, but also in the subtropics. Manifests in a chronic granulation tumor and is treated with antibiotics; in the fungal form, surgical treatment is mainly carried out.

Noma or cheek burning: is a serious bacterial disease that develops on the oral mucosa and from there affects other soft and bony parts of the face. According to WHO estimates, between 80,000 and 90,000 children die each year as a result. It usually affects children in developing countries whose immune systems are already weakened by malnutrition, poor oral hygiene and other previous diseases such as measles, rubella, mumps or meningitis.

Onchozerkosis: occurs in the tropical regions of Africa and America and is caused by a certain type of nematode. In about ten percent, the disease leads to incurable blindness, known as river blindness. The vast majority of cases are in Africa. The disease is treated with, among other things, ivermectin, which gained questionable fame during the corona pandemic.

Podokoniosis: a non-contagious form of elephantiasis, also known as non-filarial elephantiasis. Distributed in the highlands of tropical Africa, Central America and northern India. The cause is microparticles in soils with a high content of red laterites of volcanic origin, which penetrate the subcutaneous tissue through the intact skin of people walking barefoot and lead to inflammation. The victims are exposed to massive stigmatization, partly because of the smell of the inflamed skin. The most effective treatment is prevention by wearing socks and sturdy shoes and foot hygiene.

Rabies: According to a WHO estimate, it causes 59,000 deaths per year, 60 percent of which occur in Asia and 36 percent in Africa. The vast majority of cases are transmitted from dogs to humans. There are vaccinations.

Scabies (scabies): parasitic skin disease caused by the burrowing or scabies mite. The disease is now less common in industrialized countries and has been on the WHO list of neglected tropical diseases since 2013. An estimated 130 million people worldwide are infected. Treatable.

Schistosomiasis (Bilharziosis): Worm disease caused by the larvae of the genus Botbot, which spreads in warm inland waters with snails as intermediate hosts. Can be treated with the drug praziquantel. The problem is access for many infected people.

Snakebites: Every year, 5.4 million people are bitten worldwide and the WHO estimates that between 80,000 and 138,000 people die. Nevertheless, according to the World Health Organization, the problem is a neglected public health problem in tropical and subtropical countries. However, in Asia, up to two million people are poisoned by snakebites every year; According to the WHO, approximately 500,000 people in Africa require treatment every year. The problem is getting the right medical care in a timely manner. In addition to deaths, approximately 400,000 affected people suffer from disabilities each year.

Soil-transmitted helminthiases: another worm infection that, according to WHO estimates, affects approximately two billion people worldwide and kills up to 135,000 people per year.

Sporotrichosis: a fungal disease that can affect the deeper layers of the skin, the lymphatic system and even the entire body. The pathogen is Sporothrix schenckii, which occurs everywhere. The treatment is relatively simple and effective with medications.

Taeniasis/Zystizerkosis: Infections with beef or pork tapeworm.

Trachom: an eye infection caused by the bacterium Chlamydia trachomatis, which can lead to blindness if not treated. The bacteria are mainly transmitted via flies that sit on the eyes of children. It can be spread further by sharing washcloths or towels. As the disease progresses, scars form on the eyelids, the eyelashes turn inward and, with great pain for the patient, scratch the cornea until it is milky and opaque. Depending on the stage, the disease can be treated with antibiotics or surgery.

Tungiasis: Infestation of the body by sand fleas, which occur in Central and South America, Africa and Australia. The fertilized female fleas burrow into the skin and lay eggs. The increasing size causes inflammation and ulcers in the skin. The damage can also be entry points for other pathogens. The consequences can even be mutilation.

Framboesia: an infectious disease caused by the bacterium Treponema pertenue that occurs in tropical areas. The consequences can be serious deformations, for example in joints. Easily treated with medications such as penicillin.