Tropical diseases today are no longer limited to their countries of origin. Many a vacationer unsuspectingly brings back an unpleasant souvenir, and in airplanes and cargo containers an exotic carrier of tropical diseases has often been brought in as a stowaway.
What are tropical diseases?
Infographic on the transmission cycle of malaria by the Anopheles mosquito. Click to enlarge. Tropical diseases are infections that occur primarily in tropical and subtropical areas because the disease vectors need a warmer climate to survive. Typical of tropical diseases are rapid spread and often epidemic-like occurrence. The best-known tropical diseases today include malaria, yellow fever, swamp fever, dengue fever and Crimean-Congo fever, as well as sleeping sickness, schistosomiasis, leprosy and Chagas disease. These infectious diseases are common in many warm, humid regions, while others such as Ebola, Lassa fever, and Marburg virus are clustered in Africa. The incubation period of each tropical disease varies. Rarely do symptoms appear abruptly; usually they develop insidiously over a period of several weeks or months. They may cause episodes of fever, severe gastrointestinal illness or internal bleeding. Tropical diseases are often highly contagious and can only be treated symptomatically. Sometimes they leave permanent damage to health; untreated, tropical diseases are often fatal.
Causes
One cause of many tropical diseases, in addition to mosquitoes and biting flies, is ticks and other blood-sucking insects whose bites can transmit the causative agents of malaria, sleeping sickness, and similar infections. Other tropical diseases are favored by poor hygiene and a lack of infrastructure. For example, the discharge of untreated sewage into lakes provides an ideal breeding ground for many sucking and nematode worms and other parasites. If contact with worm larvae occurs while bathing or washing clothes in such contaminated freshwater, the result can be infection with schistosomiasis. Contaminated drinking water is one of the main causes of tropical diseases such as typhoid, cholera and amoebic dysentery, caused by bacteria and protozoa. Poverty, malnutrition, and poor health care weaken defenses and increase the population’s susceptibility to tropical diseases spread through droplet infection and body fluids.
Typical and common diseases
- Malaria
- Cholera
- Yellow fever
- Dengue fever
- Leprosy
- Tuberculosis
- Schistosomiasis (bilharzia)
- Chagas disease
- Ebola
- Spotted fever
- Sleeping sickness
- Japanese encephalitis
- Amoebic dysentery
Symptoms, complaints and signs
A tropical disease in the form of a viral disease caused by insects initially shows symptoms such as fever, headache, aching limbs and chills. In short-lived alternation, signs of improvement as well as renewed episodes of illness appear. Nausea, vomiting and diarrhea may also develop. In addition, itching may occur. Depending on the type of tropical disease, skin rash may also occur. Itchy wheals, facial swelling, and abdominal pain may indicate tropical disease due to worm infestation. The flu-like symptoms of tropical disease often resemble each other in the initial phase of illness. As the disease progresses, different symptoms may appear with a different potential for danger. In the case of malaria, severe sweating, dizziness and weakness may occur as the disease progresses. Malaria tropica can cause a dry cough and respiratory and intestinal problems. Symptoms of malaria disease may recur after years of inconspicuousness. In a severe course of yellow fever, symptoms such as fever, chills, and nausea may be followed by bleeding from the palate, vomiting of bile, and cessation of urine production. In hemorrhagic tropical diseases such as Ebola and Lassa fever, severe symptoms such as life-threatening external and internal bleeding and organ damage occur very quickly. In particular, kidney and liver failure can occur.
Diagnosis and course
Tropical diseases such as malaria, which involve viral infection by insects, initially cause flu-like symptoms.Fever attacks, chills, headache and pain in the limbs occur. Short-term improvements alternate with renewed episodes of illness. Diagnosis is made with the aid of a blood test. In tropical diseases caused by parasites or worms, the larva penetrates the skin and spreads through the blood and lymphatic system. Diffuse flu symptoms with febrile seizures, headache, and aching limbs may result, depending on the location of the parasite’s implantation. At times, other symptoms such as severe itching with skin rashes and palpable swelling of the spleen and liver occur. The detection of worm eggs in the stool is used to establish the diagnosis. Characteristic of tropical hemorrhagic diseases such as Ebola and Lassa fevers are short, violent courses of illness with severe flu symptoms, cough, diarrhea, multiple organ damage, and internal and external bleeding.
Complications
The complaints and symptoms of tropical diseases can vary widely and usually depend on the exact disease. For this reason, it is not possible to make a general prediction about complications. In the worst case, however, tropical diseases can lead to the death of the patient or leave permanent damage. Those affected usually suffer from severe flu and chills or aching limbs. Severe headaches, nausea and vomiting also occur and significantly reduce the patient’s quality of life. Furthermore, swelling of the liver and spleen occurs and the organs are damaged. If treatment is not given, severe itching of the skin and jaundice occur. In the further course, the patient will die if the organs are completely damaged. The treatment of tropical diseases is usually carried out with the help of drugs. Complications only occur if the treatment itself is not initiated early. Antibiotics and other drugs can defeat most pathogens, so that the diseases are completely limited. With a complete cure, the patient’s life expectancy is also not reduced in most cases.
When should you go to the doctor?
As a rule, a doctor should always be contacted immediately in the case of tropical diseases. In the worst case, it can also lead to the death of the affected person if the disease is not treated at all, so that early detection and treatment of this disease always has a very positive effect on the further course of the symptoms. The earlier a doctor is contacted, the better is usually the further course of tropical diseases. A doctor should be consulted if the symptoms occur when staying in tropical countries. A high fever combined with severe pain and chills may indicate these symptoms. Itching or pustules and papules on the skin can also indicate tropical diseases and should always be examined by a doctor. Most of those affected also suffer from coughing or even vomiting and also diarrhea. In case of tropical diseases, a general practitioner can be contacted in the first place. The further course and also the treatment depend thereby very strongly on the exact kind and the expression of the illness, so that thereby no general prediction can be made.
Treatment and therapy
Some tropical diseases, such as malaria, can be cured today if diagnosis and treatment are done in time. Especially for malaria, there are well effective drugs. For other tropical infectious diseases, where a virus is transmitted by mosquitoes or flies, there is no effective therapy to date. In the case of dengue, Hanta or yellow fever, only individual symptoms can be treated with medication, although painkillers containing acetylsalicyl (e.g. aspirin) must be avoided because of the increased tendency to bleed. In the case of sleeping sickness, the patient must be treated as an inpatient, since the drugs are highly toxic and can cause serious side effects. Common antibiotics are also ineffective against parasitic tropical diseases such as schistosomiasis, Chagas disease and filariasis (river blindness). The treatment is carried out on an in-patient basis, because only chemotherapy with strong side effects can be considered for the therapy of this tropical disease. Tropical diseases whose vectors are ticks or lice can be treated well after clear diagnosis. For example, Q fever, relapsing fever and leishmaniasis can be completely cured with antibiotic combination preparations.
Prevention
Vaccinations protect against some tropical diseases. Insect repellent and mosquito nets keep the biting vectors of other tropical diseases away, and those who avoid tap water, ice cubes, raw meat/seafood, and unpeeled raw foods at the table, do not walk barefoot, and avoid fresh water can thereby effectively prevent tropical diseases.
Aftercare
For tropical diseases, the form of medical aftercare depends on the exact disease. For some tropical diseases that are readily curable, no follow-up care in the medical sense is necessary at all. These include, for example, hookworm infestation, O’nyong-nyong fever and endemic syphilis that has not yet lasted long. In these cases, the disease ends on its own or can usually be completely conquered by rapid administration of antibiotics. The majority of tropical diseases, however, are serious infectious diseases. In many cases, these have the potential to severely attack organs and other tissues and weaken the body. Aftercare following treatment with drugs is therefore often aimed at restoring strength and providing good care for the patient. Especially in the case of cholera and the other tropical diseases that cause severe fever, increased intake of fluids and nutrients is indicated for some time after treatment. In the case of tropical diseases that cause severe damage to the skin, subsequent wound care is necessary. In the case of some tropical diseases, the main purpose of follow-up care is to check for residual pathogens. In this way, therapy can be continued if necessary and it can ultimately be ruled out that tropical diseases are spread to other areas.
What you can do yourself
Patients suffering from a tropical disease such as malaria, cholera, onchocerciasis or yellow fever must seek medical treatment. The most important self-help measure is always to follow the doctor’s instructions, accompanied by rest and bed rest. Depending on the disease, other measures apply. In the case of various diseases such as cholera, dengue fever or spotted fever, there is an obligation to report the disease. Patients should inform the competent authority if not already done so by the physician. To avoid transmission of the pathogen, contact with healthy persons must be restricted. In the case of cholera and other tropical diseases affecting the gastrointestinal tract, the diet must be changed. Patients must drink enough water and ensure that their fluid and electrolyte balance is balanced. Homeopathic remedies may be used to accompany treatment with antibiotics. Close medical monitoring is necessary for severe conditions such as onchocerciasis, which can lead to blindness. Patients should watch carefully for unusual symptoms and inform the doctor if necessary. The most important measure is always to carry out drug treatment and otherwise adjust living conditions to the individual symptom picture.
