Are people still concerned about tropical diseases whilst travelling? The answer varies. However, there are plenty of tropical diseases out there. Depending on the type, duration and region of travel, the likelihood of contracting it varies. It is therefore obvious that a long-term backpacker is usually exposed to different sources of infection during their trip than a package traveler. For a certain risk of infection, the continent, the climatic region, the geography and ecology of the country visited are important. Some countries do require certain vaccines to enter. This may include jabs for yellow fever, malaria etc. You may want to also read about neglected tropical diseases. Let’s look at some of the most common types.
The dangerous infectious disease malaria is caused in humans by different types of a protozoon. It therefore occurs in different forms:
- Malaria tropica is the most dangerous form of malaria and is caused by the pathogen Plasmodium falciparum. Malaria tropica is the most frequently imported disease after traveling in Sub-Saharan Africa and the most common cause of death among people returning to the tropics.
- Malaria tertiana is characterized – without proper treatment – by recurring relapses. These are triggered by the liver forms of the vivax / ovale pathogen.
- Malaria quartana is comparatively harmless and is caused by malariae.
- Malaria quotidiana, which is similar to Malaria tropica, is only found in certain regions of Southeast Asia. These symptoms are very uncharacteristic, but often present as a fever. It may also include sickness, diarrhea and jaundice.
Like malaria pathogens, leishmaniasis are protozoa and live in body cells in humans and other mammals such as dogs and rodents. They are also found outside of cells as spindle-shaped pathogens in the gastrointestinal tract of various sand or butterfly mosquitoes. Most commonly, the disease is transmitted through the bite of these very small mosquitoes.
Leishmaniasis occurs in different regions, including in the Mediterranean area. In the last ten years, the pathogen with the sand flies has spread to Central Europe. Depending on the type of leishmania, the pathogens can cause diseases of the skin, the mucous membranes or the internal organs. The condition of the infected person’s immune system is decisive for the type and severity of the disease.
Tropical viral diseases – ARBOviruses
Whether in Africa or Asia, America or Oceania – the tropics are home to countless viruses. Many have spread to Europe in the last few decades. The most important and largest group are viruses that are transmitted by “arthropods” (these are arthropods such as mosquitoes and ticks). They are called “ARBOviruses” (ARBO = “arthropod born”). The majority of infections usually run unnoticed or as a mild illness, whereby the incubation period is always between a few days and a maximum of three weeks. The duration of the illness is variable. Infection with several viruses at the same time is possible.
Transmission and dissemination As Rickettsioses a group of exotic and native disease is referred to by different, proliferating in the cells of humans and animals bacteria. The species relevant to travel medicine are transmitted by ticks or mites, which is why the diseases are referred to as tick bite fever or rickettsial pox. Well-known representatives are also typhus, which has become rare today, and Q fever, which is transmitted to humans worldwide and is airborne.