Tropical diseases: symptoms, prevention and therapy

Tropical diseases: symptoms, prevention and therapy

We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

More and more Germans are traveling to the tropics. There is often a lack of knowledge about tropical diseases common in these countries - and how to deal with them fluctuates between extremes. Some panic when there are a handful of plague cases among more than a billion Indians, others are surprised that there is no kiosk in the Mohave Desert to buy drinks.


The following applies to all travel countries: Diseases have causes, and some of these causes can be avoided.

1) About two months before the start of the trip, you should find out which vaccinations are required in the country of travel and which are advisable. Then you should check your vaccination card, which vaccinations still work, which ones you have to repeat and which you don't have.

It's also about the regions they visit and the way they travel. For example, if you stay in mid-range hotels in India and book organized tours, you are unlikely to have contact with a dog or jackal who has rabies.

On the other hand, if you are backpacking through the country, sleeping in a tent or outdoors, vaccination against rabies is highly recommended.

2) You should generally observe simple hygienic measures.
This includes:

  • Boil tap water and do without well water if possible.
  • Do not eat unpeeled fruit.
  • Avoid homemade ice cream.
  • If possible, do not eat at street vendors at all.
  • Wearing long clothes, sleeping under a mosquito net, putting on a mosquito hat in swampy areas, using mosquito repellent.
  • Wash your hands, especially before and after eating if you have been on the bus or train, touched doors or other objects. Most of the infections run from hand to mouth.
  • Rub the skin with a cream after washing.
  • Use a mouthguard against smog and pathogens in high-risk areas such as the slums of large South American cities.
  • Avoid petting stray animals or at least wash your hands thoroughly afterwards.
  • Keep sprays or powders with you against fleas, mites and bugs.
  • Take your own bedding with you. In hotels with poor hygiene, sleep in your own sleeping bag and if necessary put a plastic bag over the bed sheet.
  • Bring bathing shoes that you put on when you use the shower.

The hygiene bag

Small things often prevent big things. Our “cosmetic bag” already helps to stop infections.

It should contain:

  • Toilet paper,
  • Toothpaste and toothbrush,
  • Soap,
  • a handkerchief (wash regularly with clear water),
  • Razors and after shave (disinfected),
  • Comb (also brushes insects and parasites out of the hair),
  • Sunscreen,
  • Skin cream (cracked skin opens the way for many pathogens).

Lack of water

The most dangerous killer on tropical trips is not the tiger or the white shark, but lack of water. No danger is so underestimated! Never start without water reserves - in the wild as in the city. Never think you will find water anywhere.

Proximity to cities is deceptive - if you die five kilometers from the next place, they still die.

In hot deserts we need several liters of water a day. If we are driving, this does not offer security. Maybe the next petrol station has closed, then we'll dry out further, or the car will break down.

Never think "there is a river on the way". Perhaps it is not currently carrying water or you are losing the path.

Water shortages threaten life long before the organs fail. It is fatal that we lose focus and orientation when we urgently need it to get help.

We are confused, our concentration suffers, we become listless, the tongue swells and we see things that do not exist.

Our urine turns dark and stinks.

We prevent water shortages by constantly carrying at least two liters of water with us as an iron law - considerably more on trekking tours.

  • We avoid sweating.
  • We postpone strenuous marches and work in the night or in the shade.
  • We wear light-colored clothes.
  • We protect ourselves from the wind because wind promotes evaporation.
  • We don't eat anything except water-rich fruit.
  • We don't drink alcohol and we don't smoke.
  • We never drink salt water or urine when we show symptoms. This disrupts the osmotic balance and can lead to death.
  • We clean the water with disinfectant tablets; if there is a lack of water, even the loss of fluid in a small diarrhea quickly leads to death.

Motion sickness and symptoms

The term tropical diseases does not include all diseases that tourists encounter on long-distance trips. Rabies or malaria, for example, are not limited to the tropics, but are now under control in Central Europe.

Dengue fever

Aedes aegypti, a mosquito species, transmits a dangerous virus, dengue fever. Tens of thousands of people in countries like Vietnam and Venezuela fell ill. Symptoms include severe pain in muscles, joints, and limbs. Bleeding and shock symptoms can follow.

The fever cannot be cured, but only alleviated, for example with paracetamol - but never take aspirin because of the risk of bleeding! In areas where dengue fever is rampant, all measures to ward off diurnal mosquitoes are a must: mosquito hat. Mosquito-repelling sprays and, if necessary, a strongly smoking fire.

Yellow fever

The yellow fever also transmit mosquitoes to humans. The virus is endemic to parts of Africa, as well as Central and South America. There is no danger in Asia and the Caribbean, but experts fear that the virus will spread to Asia because suitable hosts and vectors live here.

The mosquitoes suck on infected monkeys, then transmit the virus to other monkeys or to humans. Or they suck blood from sick people and transfer it to other people. In nature monkeys are the main bearers, in cities humans.

The transmissions from monkeys to humans mostly only lead to local epidemics in forest villages. In contrast, the disease breaks out in large numbers in metropolitan areas.

The incubation is 3-6 days. After transmission, the virus multiplies in the body. Those affected suffer from a high fever, which also rises quickly. There is also nausea and pain in the head like muscles. The conjunctiva becomes inflamed and the pulse slows down.

Then the symptoms disappear and those affected think they are recovering. But now the second phase begins, in which the yellow fever affects the organs. Liver and kidneys fail, the body is poisoned. Every second patient dies in this phase.

Yellow fever also triggers heavy internal bleeding. Sometimes the yellow fever is not as bad.

No medicine helps against the disease, and medicines only alleviate the symptoms.

If you are in yellow fever areas, you should definitely use repellants, sleep under mosquito nets and seek their protection, especially at dusk - then the animals are active.

Yellow fever vaccination

A yellow fever vaccination is mandatory when entering many countries. At the same time, weakened viruses on chicken eggs are propagated - the vaccination is carried out with a syringe under the skin. Such a vaccination is absolutely advisable when traveling to Africa or tropical America: the protection is almost 100% - and that in the case of a disease that leads to death in every second unvaccinated person.

The basic vaccination is given at least ten days before arrival and may only be carried out by official vaccinators. Vaccination lasts a lifetime, but some states require it to be renewed after ten years.

Side effects of vaccinations

Side effects are very rare. Every twentieth person vaccinated reports a slight headache. In any case, the risk of catching the virus in epidemic areas is far more dangerous than possible side effects.

If you do not have vaccination protection and have been to yellow fever countries, other countries sometimes refuse entry.

Lassa fever

Lassa fever is a classic tropical disease, because it only occurs in West Africa from Senegal to Nigeria.

A rat, Mastomys natalensis, transmits the fever in contact with humans. Infected people then transfer it to other people.

The incubation lasts 2-21 days. The disease begins with limb, muscle and headache, nausea and fatigue, and fever around 40 degrees. At first it can easily be mistaken for the flu.

However, the throat becomes inflamed after three or more days. Those affected now react apathetically to external stimuli. The lymph nodes on the neck swell and hurt. After seven days, spots spread on the skin, nodules on the face, neck and arms, and later on the whole body. There are also abdominal pain like colic, the feces become mushy to watery.

Other lymph nodes are also swelling and eating is difficult. The kidney functions are disturbed. After the seventh day, the fever lowers, but often comes back full force a few days later. The death rate is between 50 and 90%.

There is no therapy and there is no vaccination. The only protection is to avoid contact with rats. Carry a long stick with you in affected countries and poke it into possible hiding places before entering or sitting in it.


Loa-Loa denotes a worm infestation that the brakes transmit. The worms are nematodes of the Filarioidea genus. Loa-Loa is common in West and Central Africa.

The incubation lasts for months, and usually those affected only feel the first symptoms after the trip. The nematodes migrate in the connective tissue of the skin and mucous membranes, their larvae also in the blood vessels. The skin swells, turns red and itches.

A deworming agent, diethylcarbamazine, helps against Loa-Loa. Affected people have to go to a hospital. There is no vaccination. The same protection measures against mosquitoes help against braking, but with special repellents against flies.


Leishmaniases are skin diseases that transmit mosquitoes. The so-called oriental bulge occurs in Asia, the Middle East, around the Mediterranean, East and West Africa as well as in tropical America. The viscoral Leishmaniasis is rampant from India and Pakistan across the Middle East to Central and South America.

The incubation on the skin can take months, the organ involvement often shows up after years. After the stitch, a red ring appears without swelling. With this symptom, travelers should see a doctor. The skin leishmaniasis appears as necrotizing skin ulcers, the visceral leismaniase due to fever, swelling of the liver and spleen, and pain in the stomach and intestines.

Various antibiotics help. Since sandflies transmit the disease, repellents and mosquito nets help.

Hepatitis A

The hepatitis A virus is found in contaminated food, for example in seafood, but also in drinks and toilets.

The virus attacks the liver, which becomes inflamed and the skin turns yellow. Healthy people recover relatively quickly from the disease, but at least three out of a hundred die in people with a weak immune system and in the elderly.

The virus is most common in warm countries. Already in Turkey there is a 50 times higher risk of being infected with the virus than in Germany. An extreme risk in tropical Africa and America, and southern Asia is also a danger zone.

Vaccination against hepatitis A is routine - such a vaccination works almost a hundred percent. It is covered by the health insurance companies.


The most common motion sickness is not malaria, also not worm infestation or an infectious rat bite, but diarrhea. 70% of all long-distance travelers experience such a diarrhea at least once in their life.

“Travel diarrhea” is, however, a collective term - it encompasses various infections. Coli bacteria are the usual suspects, but viruses are also an option.

Travelers in India, Africa, Malaysia, Indonesia and Indochina are most at risk. But Mediterranean tourists, visitors to Japan or Pacific globetrotters are also familiar with the problem.

Most of those affected also know about the trigger, because the liquid bowel movement usually begins a few hours after a drink or a meal. Without treatment, it lasts three to five days.

The diarrhea does not threaten life, but it can cause serious problems. The most lightly come from whoever has a hotel room with its own toilet. It becomes more difficult if the infection announces itself when the travelers are traveling overland. Quite a few were stuck in dark toilets somewhere on the Bay of Bengal at night while the bus started without them.

Women who are looking for sexual adventures should be particularly careful, because the diarrhea cancels out the effects of the pill.

Preventing diarrhea is simple but consistent: cook food, peel fruit, do not eat at street stalls, and wash your hands.


Rabies is a largely underestimated threat. Although the Lyssa virus is under control in Central Europe, it is a fatal danger in Africa and India: probably 20,000 people die of it in India alone.

Whoever breaks out of the disease always dies (almost). Infected animals, mainly the fox in Europe, mostly dogs in India and Africa, vampire bats in South America, but also wolves, jackals and cats transmit the plague with their saliva.

Rabies sometimes breaks out in days, often months, and sometimes years.

Pay attention to unusual behavior of animals in affected countries. Infested wild animals behave unnaturally trusting, they gasp for air, look irritated, stagger, are emaciated or snap around. Beware of street dogs: 99% of infections in developing countries come from dogs, and Indian children learn early on to ward off the animals with a stick.

In South America, the vampire bat of the genus Dendrobatus also transmits the virus. These animals grate the skin of warm-blooded animals with their teeth and drink their blood. Infected bats transmit the virus like dogs with a bite. A mosquito net helps against the bats.

Humans become infected through bites from sick animals. But even if a sick dog licks the skin, a small wound is enough for the virus to get into the body. The saliva of the animal can also get into the organism through the eye, nose or mouth mucosa if travelers rub there with unwashed hands.

Beware of animal carcasses! The dead animals are full of viruses even weeks after their death. Examining a dead jackal and then digging into the nose is a royal way to get infected. The Lyssa pathogen is very resistant to cold and decay.

The biggest danger is not that a sick dog bites, but to help a "cute puppy". The virus often affects baby dogs, and anyone who scratches their arms, which is almost a part of outdoor travel, and then lets the poor animal lick their hand is at great risk.


In the incubation period, the onset of the disease can be pushed back safely, after the onset of the disease it is incurable. The virus travels along the nerve pathways to the spinal cord and further to the brain. It multiplies there.

In the first phase, the sick appear paranoid. You feel sick, have a fever and headache. Then spasms of the swallowing muscles follow, which led to the old term “water aversion” for the disease.

The second phase is shown by cramps that are getting stronger. The eyes redden, the mouth dries out, the fingers twist as in rickets, the sufferers suffer excruciating pain, their skin becomes hypersensitive; they suffer from delusions and become aggressive. Various external stimuli are a torment for them. After a few days they fall into delirium and die.

There is no cure, only complete rest, darkness and anesthesia can help the sufferer. They must be isolated immediately because their saliva, urine and tears are extremely infectious.

Rabies vaccination

Vaccination should be given immediately after contact with an infected animal, and a total of five vaccinations are given in 28 days.

Whoever undertakes outdoor tours in high-risk countries should in any case get vaccinated beforehand. Vaccination is even mandatory for professions at risk. This applies to foresters, hunters, zookeepers or veterinarians. Backpackers in India, Bangladesh, Vietnam, Cambodia, Bali, Nepal, China or Thailand should also urgently take care of a vaccination before the trip. Hotel travelers do not have to be vaccinated, but should avoid stray dogs.

Vaccination three times within a month provides almost 100% protection. It must be repeated the next year, and then again after three years.

Other tropical diseases and their symptoms

Diseases that require precaution when traveling to the tropics are also malaria, diphtheria and tetanus, polio. Tuberculosis, typhoid, cholera and encephalititis, as well as hepatitis B.

Malaria means bad air, and the swamps from the swamps were thought by the ancient Romans to be the cause of this febrile illness. In fact, it is not the swamps themselves, but the mosquitoes that develop there from larvae that transmit malaria.

Precaution means to find out before you travel in which biotopes the mosquitoes are common, at what time of the day they swarm out and to pack the usual equipment against mosquitoes.

You should discuss with your doctor whether you are prophylactic. The preventive drugs against malaria have side effects that resemble a flu infection, and they do not prevent infection, but mostly kill the pathogens during their development.

But they only offer limited help against tropical malaria, which is rampant in equatorial Africa, for example. It is often better not to get treatment until you have an infection.

Trekking tourists should always carry a dose of malaria medication in their backpack.

To eat and drink

Healthy eating prevents many diseases, but is difficult on many routes, in dirty slums like in the rainforest.

For example, an emergency ration includes:

  • Nuts,
  • Granola bar,
  • Raisins,
  • Dates,
  • Disinfection tablets,
  • Sugar / dextrose,
  • Salt.

What belongs in the first aid kit?

Trekking travelers in particular are often dependent on themselves. They absolutely need bandaging material, namely:

  • Gauze bandages,
  • Bandage plasters,
  • Adhesive plaster,
  • Elastic bandages,
  • Disposable gloves,
  • Disinfectant,
  • Tweezers,
  • Safety pins,
  • Bandage scissors,
  • Medical thermometer.


Travelers should carry all medication for specific ailments. Generally belongs in the medicine bag:

Anthistamine gel for insect bites and sunburn, paracetamol or ibuprofen for pain and fever, diclofenac ointment for bruises and strains, remedies for stomach complaints, panthenol for burns, wounds and water bubbles, eye drops e.g. Berberil for eye infections, Dorithricin for sore throat, Simomatort for cough against runny nose, ointments or powder for fungal diseases.

Even more important than medication are:

  • Water purification tablets,
  • Vitamin and mineral tablets, for example vitamin C, magnesium or iron. On long journeys in nature, the vitamin intake through food can be insufficient,
  • Rehydration mix. Diarrhea leads to a loss of fluids, minerals and nutrients. The cocktail to make up for this deficiency is especially important for children.

Home remedies and tinctures for the most important complaints also help: sage for tea takes up little space, as does dried mallow, lemon peel or mint.

Rule number 1 is: be careful with water, especially ice. Soft drinks in bottles are not very problematic (clean the outside of the bottle if necessary), the situation is different for draft beer, fruit juices or milkshakes. Tea, coffee and other hot drinks are mostly drinkable because the water has been boiled.

Rule number 2 means: Pay attention to the food. Avoid seafood as well as not enough heated meat, especially mince. Is the restaurant clean, the plates and cutlery as well as the kitchen? Then this probably also applies to the food. Does the kitchen boy in Delhi wash the plates a meter from the street wall next to the urine flow? Then fingers away.

In general, the more extreme the tour and the more remote the route, the more travelers have to prepare to be their own doctor in an emergency.

On trips in the wilderness alone, cannulas and gloves also belong in the pharmacy, as well as antibiotics. Take care of sets that help with snake bites, both against blood and nerve toxins. Find out from a doctor and prepare yourself for such trips with courses, for example in wilderness schools. (Dr. Utz Anhalt)

Author and source information

This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.

Dr. phil. Utz Anhalt, Barbara Schindewolf-Lensch


  • Robert Koch Institute (RKI): Dengue fever (accessed: August 16, 2019), rki.de
  • Private Tropical Institute Dr. Gontard GbR: Yellow fever (accessed: August 16, 2019), tropeninstitut.de
  • Centers for Disease Control and Prevention (CDC): Parasites - Loiasis (accessed: August 16, 2019), cdc.gov
  • Merck and Co., Inc .: Rabies (accessed: August 16, 2019), msdmanuals.com
  • Robert Koch Institute (RKI): RKI guide Lassa fever (accessed: August 16, 2019), rki.de
  • World Health Organization (WHO): Leishmaniasis (accessed: 16.08.2019), who.int
  • Professional Association of German Internists e.V .: Hepatitis A (accessed: August 16, 2019), internisten-im-netz.de

Video: Gonorrhea Infectious Diseases. Lecturio (June 2022).