Diseases

Malaria is a serious, sometimes fatal disease caused by a microscopic parasite called Plasmodium. Mosquitoes of the Anopheles genus are used to transmit the pathogen from person to person.

5 different types of Plasmodium (P. falciparum, P. vivax, P. ovale, P. malariae, and recently also P. knowlesi) can cause malaria in humans. Infection with Plasmodium falciparum – this disease is called malaria tropica – can have a fatal outcome.

Symptoms

Typical symptoms of malaria are fever, chills, body aches, a general feeling of illness, and headaches. But tropic malaria in particular can hide behind a multitude of symptoms. But fever is always the main symptom!

The disease is widespread in tropical and subtropical countries.

prevention

Vaccination research has been going on for decades, but despite great progress in recent years, there is still no vaccination available for travel medicine (the already approved preparation has too little protective effect for use when travelling). However, there are proven and safe ways to protect yourself from this disease. Be careful with tips from people who have lived in malaria regions for years – or always – and who may explain to you that the disease is not that bad and that you can also prevent it with “easy” means. Anyone who has survived malaria develops a partial immunity, which does not protect against recurrence, but against the feared severe courses. Since people who live in malaria areas have infections again and again, they are usually partially immune and actually experience malaria more like a severe “flu” . However, malaria can be deadly for non-immune individuals – mostly children (in Africa a child dies of malaria every 30 seconds) and tourists!

1. Protection from the carrier (protection from mosquito bites)
2. Protection against the pathogen (preventive intake of malaria medication = malaria prophylaxis)

Various drugs are used for this. Due to the very different resistances of malaria pathogens worldwide, not every substance is effective everywhere. You have to make the decision about the right antimalarial medication for you together with your doctor. Your destination, the time of year, the type of trip, but also your personal intolerances, underlying illnesses and needs must be taken into account.

Dengue fever is a global viral disease that affects virtually all tropical and subtropical regions of the world.
The symptoms are those of an acute, high fever illness with severe headaches, joint and limb pain. A patchy rash all over the body (not itchy!) resembling a measles rash is common.
After a few days, the acute phase is over and the patients recover.

The threat of the disease lies in the dreaded complication of dengue hemorrhagic fever, a progressive form in which heavy bleeding occurs due to the consumption of blood platelets. This complication can be fatal, especially if good intensive care is not available.
Due to an immunological reaction of antibodies against the various dengue viruses (there are a total of 4 different types), this severe form is more common in secondary infections than in the first infection.

How do you get infected?

Dengue fever is transmitted by mosquitoes, primarily Aedes mosquitoes (also known as tiger mosquitoes because of the distinctive stripes on their legs). Direct transmission from person to person is not possible.

Incubation period:

Relatively short, 3 to 10 days.

Diagnosis:

The symptoms together with the travel anamnesis show the way. The diagnosis is made either by direct detection of the virus or of components of the virus (antigen) in the blood – in the first few days of illness only these tests are positive. Rapid tests are often available in the heavily affected countries, which give an indication of the infection within a short time. Later, antibodies form in the blood, which can be detected.

Prevention:

Mosquito repellent is the primary protective measure. However, the Aedes mosquito is not only active at dusk, like other mosquito species, but also bites during the day.
After decades of fruitless research, a vaccine against dengue fever was developed and approved for the first time in 2015. However, it quickly became apparent that the protective effect is not perfect and that people who become infected despite being vaccinated can even develop more severe symptoms. In travel medicine, it could only be used for people who have already survived a dengue infection. However, the preparation is currently not approved for use in travelers in Europe.

Therapy:

No specific therapy possible. Nevertheless, an early diagnosis is important, since rapid intensive care support can save lives in severe cases.

Most common viral encephalitis in Asia.

The Japan Encephalitis Virus is closely related to the TBE virus, but only occurs in subtropical and tropical regions of Asia.

As with many viruses in this group (flaviviruses), most people who become infected have a very mild or even completely symptom-free course. Only a small percentage – it is estimated at around 1% – takes a severe course. However, this is then marked by pronounced neurological symptoms: loss of consciousness, seizures, paralysis. In areas with good medical care, 5-10% of these patients die, otherwise up to 40%!
Long-term consequences are very common in survivors: concentration disorders, motor deficits.

How do you get infected?

The disease is transmitted by mosquitoes, primarily Culex mosquitoes. These are mainly active at dusk.

incubation period

Relatively short, 5 to 10 days.

Diagnosis:

The diagnosis usually has to be made clinically, i.e. based on the symptoms. However, these are no different than other inflammations of the brain. It is therefore essential that the treating physicians consider the possibility of Japanese encephalitis.
Specific antibodies can be detected in the spinal fluid after about a week.

Prevention:

mosquito repellent!

Vaccines against Japan encephalitis have been around for many decades. The older vaccines developed in several Asian countries are no longer used in travel medicine since modern products with few side effects have become available.

Therapy:

no specific therapy possible.

Exciter:

Yellow fever virus, from the flavivirus family, and thus related to the causative agents of TBE, Japan encephalitis and dengue fever

Illness:

Originally a disease of animals, especially monkeys. Transmission is by mosquitoes.
For many people, the infection has no consequences, no symptoms appear, but you are immune as a result.
When symptoms do occur, they can range from mild flu-like symptoms to the most severe and often fatal. In severe cases, liver failure (which causes the yellowing of the eyes and skin that gives the disease its name), severe bleeding and circulatory failure occur. Of the tourists suffering from yellow fever who were treated in Europe and the USA in recent years, 36% died.

Prevention:

As with all mosquito-borne diseases, protection from bites is important.
The yellow fever vaccine is a live vaccine that has been established for decades and offers excellent protection against the disease.

Therapy:

No medication available for the virus. Treatment can only focus on reducing complications and general intensive care measures such as circulatory support.

The Zika virus was discovered and described by chance in 1947. Since the disease caused by Zika was considered a harmless short-term fever episode and no complications were known, it was hardly noticed.

Only larger outbreaks in Micronesia and French Polynesia showed that the disease can spread rapidly.

With the introduction of the disease to Brazil, a hitherto unknown epidemic of this magnitude occurred. Due to the enormous number of cases, the potential of the virus to lead to severe deformities if infected during pregnancy was noticed for the first time.

During the peak of the epidemic, women planning to have children were advised against traveling to a Zika-endemic area. In recent years, however, the disease has almost “disappeared” again. Only isolated cases are reported, so the risk for travelers has dropped back to practically 0.

How do you get infected?

Transmission through mosquito bites (Aedes mosquitoes), but transmission through sexual contact has also been described.

incubation period

short, just a few days.

Symptoms:

Fever, muscle and body aches, skin rashes, sometimes reddening of the eyes.

Prevention:

mosquito repellent

Viral disease spread almost worldwide with ALWAYS a fatal outcome. Few regions of the world have been able to successfully suppress/eradicate the disease or are fortunate that it has never been introduced.

How do you get infected?

The disease is transmitted through bite and scratch injuries from mammals. In most cases, the culprits are dogs, less often cats, monkeys and bats.
In Europe and the US, the main risk to humans comes from wild animals, as pets are vaccinated against rabies (raccoons, bats in the US, foxes in Europe). In Austria, the disease was practically eradicated in foxes through baited vaccination campaigns). Dogs are still the most common carriers in developing countries. The World Health Organization estimates around 60,000 deaths from rabies worldwide each year.

incubation period

It often takes weeks or even months from the bite injury to the onset of the disease. During this time, the infected person is completely symptom-free.

Diagnosis:

The diagnosis usually has to be made clinically, i.e. based on the symptoms. However, these are no different than other inflammations of the brain.

Prevention:

There is an excellently effective and well-tolerated vaccination available.

Therapy:

No specific therapy is possible. The disease is almost always fatal. Even modern intensive care measures cannot save the patients.

What to do after an animal bite

Wash the wound thoroughly (with soap and water)
If the animal has an owner, try to get all contact details (if the animal is vaccinated, there is no danger). The animal should be captured (NOT by you!) and observed for several days.
Seek medical help immediately.

The further procedure in the hospital depends on your vaccination status:
a) you have been vaccinated against rabies (i.e. you have been vaccinated at least twice BEFORE the trip) 

• 2 booster shots 3 days apart

b) you are not vaccinated (i.e. you were not vaccinated BEFORE the trip)

• One dose of immunoglobulin (as early as possible!): 20 mg/kg body weight. Ideally, the liquid should be injected into the tissue around the bite site; if the area is very small, or there is little tissue around the bite, the rest of the immunoglobulin is injected into the buttock muscle.
  
  and additionally
  
• 4-5 doses of rabies vaccination within 28 days (the first dose together with the immunoglobulin, see above – further doses 3, 7, 14 and possibly 28 days after the first)
  (in some countries a slightly different, also very effective scheme is used: 2 vaccination doses on the same day as the immunoglobulin, one further on day 7 and 21)

Preventive vaccination against rabies

2 partial vaccinations at least 7 days apart (if possible 3-4 weeks apart) before the trip.

What good is a vaccination before the trip if you still have to be vaccinated again after a bite?

1. The vaccination scheme after an animal bite is simpler: only 2 vaccinations are necessary instead of 5.
2. The administration of immunoglobulin is not necessary! This means no risk of being infected with hepatitis or AIDS from improperly produced immunoglobulin. In addition, immunoglobulin preparations are very difficult or impossible to obtain in many countries.
3. The vaccination does not have to be done immediately, but within the first 5 to 7 days, since antibodies are already present – this gives time to go to a well-equipped hospital or even to go home.

Caution!
The behavior of rabid animals is often unremarkable!
Do not rely on the supposedly “typical” signs of rabies: foaming at the mouth, aggressive behavior, fear of water

Larva migrans of the skin occurs after contact with larvae of dog or cat hookworms. The tiny larvae penetrate through the skin, where they can survive for several weeks. They slowly migrate (a few centimeters a day) under the skin, causing intense itching. A skin rash traces the meandering course of the hike. Through severe scratching, the affected person can injure the otherwise intact skin and pave the way for bacterial infections.
The disease is found in most warm, humid regions of the world.

How do you get larva migrans of the skin?

The larvae, found in the faeces of worm-infested dogs or cats, contaminate beaches and places with damp soil. Upon contact with human skin, the larvae penetrate. Holidaymakers endanger themselves by walking barefoot or by sitting or lying directly (without a blanket or towel) in the sand or on the ground.

Incubation period:

Symptoms begin immediately after the larvae penetrate the skin (this takes a few hours).

Diagnosis:

The typical snake-shaped marks, mostly on the legs or buttocks, are easily recognizable. Itching is also characteristic.

Prevention:

Do not walk barefoot on tropical beaches and wet soil. Use beach towels or mats on the beach and, if possible, choose spots that get flooded by the tide (regularly washing away animal feces should minimize the risk here).

Treatment:

The disease heals by itself after weeks (or months), but due to the itching, hardly anyone has that much patience. Both local therapies in the form of ointments and very effective tablets are available.

Giardia is a microscopic parasite that affects the small intestine. The most common symptoms are loose stools, possibly lighter in color and slimy, especially in the morning. There is also nausea, abdominal cramps, flatulence and foul-smelling gases.

Although harmless, the condition can persist for months if left untreated, potentially leading to weight loss and malnutrition.

How do you get Giardiasis?

The quite resistant cyst form of the pathogen is ingested through contaminated water or food. A few cysts are enough to infect a person.

Giardia actually occurs worldwide, but of course it is most common in areas with poor sanitary conditions. Many travelers become acquainted with the pathogen, especially in India and Nepal. Occasionally, small epidemics are also reported in Europe or the USA, especially when water used for bathing and swimming has been contaminated with faeces.

Incubation period:

The incubation period can range from 3 to 25 days. As long as the patient is not treated, he excretes infectious cysts, which can also be transmitted directly to others under unhygienic conditions (e.g. during sexual intercourse)

Diagnosis:

The definitive proof is the microscopic detection of Giardia cysts in the stool.

Prevention:

Be careful with drinking water and food! The cysts are quite resilient and are not always reliably killed by chemical treatment of drinking water.

Treatment:

Metronidazole or tinidazole (antibiotics) are usually prescribed. Although relapses occasionally occur, treatment usually works well.

Typhus is caused by a bacterium of the salmonella family (Salmonella typhi), but it is not a typical diarrheal disease! The main symptoms are fever, loss of appetite, lethargy and intestinal symptoms, which usually manifest themselves as constipation and only very occasionally as diarrhea. Typhoid can be life-threatening without treatment.
The disease is widespread worldwide, so it is not a typical “tropical disease”, the frequency has to do primarily with the prevailing hygienic conditions.

How do you get typhoid?

Infection occurs through contaminated food or unclean water. Smear infections (hands, objects) are also possible.

Incubation period:

The incubation period of the disease depends on the amount of bacteria one has unknowingly ingested. It is usually between 1 and 3 weeks. In rare cases, symptoms can appear after 3 days. Individual reports of particularly long incubation times of up to 3 months are also known.

Diagnosis:

In the early phase of the disease, the pathogen can be detected in the patient’s blood, after about 1 week it can then be detected in the stool.

Both methods are not available in many developing travel countries, where the diagnosis is made on the basis of the symptoms, which unfortunately leads to very frequent misdiagnoses.

Prevention:

The usual tips for avoiding traveler’s diarrhea also reduce the risk of contracting typhoid. There is also a vaccination that is well tolerated, but unfortunately does not have a 100% protection rate.

Treatment:

The disease is easily treatable with antibiotics. However, increasing resistance to salmonella is causing problems for us worldwide. Substances that were standard therapy 10 years ago can no longer be used today.

Vigilance is required even after successful therapy, as relapses can occasionally occur.

So-called sleeping sickness is an infection with trypanosomes (microscopic parasites) transmitted by the bite of a fly called TseTse.
As a result, a so-called eschar develops at the sting site, a relatively large, painful swelling whose center is darkly discolored.
The disease occurs in East and Southeast Africa (East African form – has become rare in recent decades) and in Central and West Africa (West African form – especially in the Congo, as there are no containment measures in place).
Only a few cases have been reported among travelers.

How do you get infected?

The transmitting fly is active during the day and mainly feels at home in savannah areas. Unfortunately, it can also be found in safari parks in East Africa, from Tanzania to South Africa.
The appearance is most reminiscent of domestic horseflies – significantly larger than a house fly. They are attracted to moving objects and the dust that is thrown up, and like to follow safari jeeps. Even good insect repellents are not 100% protection, additional solid clothing (long pants and sleeves) is important. The sting is painful, even in the many cases where no disease is transmitted!

incubation period

Usually 3 days to a few weeks for the East African form, months to even years for the West African form of the disease.

Diagnosis:

Important is the clinical suspicion, blood tests can prove the disease.

Prevention:

Keep vehicle doors and windows closed whenever possible. Bug spray can make rooms safe.
There is NO vaccination.

Therapy:

Even if drugs exist to treat sleeping sickness, their side effects are so unpleasant that the entire focus must be on preventing the disease.

Schistosomiasis, also known as schistosomiasis, is caused by parasitic worms. The complicated life cycle requires a special type of freshwater snail, in which the leeches complete part of their development. This means that schistosomiasis only occurs where these snails live. Infected snails release a large number of worm larvae into the water, which then look for a “victim”.

The larvae, which have successfully penetrated the body, develop into adult worms, which live near the bladder or liver, depending on the type of schistosome. Although it is not a very pleasant idea to have such “roommates” – the adult worms themselves do not cause any symptoms of illness. The problems and dangers of the disease arise from the eggs that are laid in large numbers. Actually, these eggs should get out through the intestines or with the urine and thus ensure the continued existence of the worms. However, many do not reach this goal, get stuck in the tissue and die. It is the body’s inflammatory response to these dying eggs that causes the dreaded consequences of schistosomiasis.

How do you get infected?

The larvae are able to penetrate healthy skin and thus enter the human body. Even brief contact with infected fresh water while bathing, wading or swimming is enough for an infection. The larvae are so small that you cannot see them with the naked eye, sometimes you feel a slight itch right after bathing.

Dispersion

The disease is found worldwide in warm climates, up to 200 million people are affected! It is particularly common in sub-Saharan Africa. In many areas of Asia and in Brazil, it was able to be pushed back by rigorous control programs.

Symptoms

Onset phase: Under certain circumstances, slight itching immediately after swimming.
Similar symptoms also exist in Europe – called swimmer’s dermatitis or cercaria dermatitis. It is caused by larvae of schistosome species that parasitize birds. In humans, the larvae die shortly after penetrating the skin, so they CANNOT develop into worms. They only cause an annoying, very itchy rash.

Acute phase: A few weeks after infection through the skin, some people experience an acute reaction, known as Katayama fever. High fever, severe feeling of illness, abdominal pain, joint pain. The symptoms disappear after a few days even without treatment. For many infected people, this phase does not occur at all.

Chronic disease: The inflammatory reaction to dead eggs and the resulting scarring can lead to severe dysfunction of the affected organs for years. In the intestine, this manifests itself with the formation of mucous membrane proliferation and bloody diarrhea, in the liver with symptoms similar to liver cirrhosis, in the urinary tract with inflammation, scarring narrowing of the ureters and an increased risk of bladder cancer.

All of these late effects are found almost exclusively in people who live in the endemic areas and not in tourists, and many repeated infections over the years are probably necessary for this. Infections among tourists tend to make headlines with dramatic individual reports. In some parts of our body, even a single misplaced schistosome egg can lead to catastrophe. Paraplegia due to inflammatory swelling in the spinal cord or in the brain has been reported.

Diagnosis

From about 3 months after infection, the eggs of the schistosomes are found in the urine or stool. Trained laboratories can thus prove the infection beyond any doubt.
Serological proof (antibody determination – blood test) is also possible from this point in time and is useful and quite reliable for travelers.

Prevention

There is no vaccine or medication to prevent schistosomiasis. So all that remains is to avoid contagion. Since there is no reliable way of identifying infested water bodies, fresh water in the distribution areas of schistosomiasis must generally be avoided. Salt water, fast flowing water and chlorinated pools are safe. Occasionally it is recommended to vigorously rub off after potential contact with larvae. In this way, larvae that have not yet fully penetrated can actually be rubbed off – which is definitely important in the event of unwanted water contact. As a preventive measure, however, it is by no means safe enough! The recommendation to simply swallow a dose of worm medicine after bathing is also gross nonsense and ineffective.

If you might have come into contact with schistosomes while on holiday, you should have a screening examination (antibody test) made about 3 months after your return.

Therapy

A safe and effective means of treating schistosomiasis is available. In most cases, a one-day cure is sufficient. In many cases there is even a certain improvement in the late damage.

The term traveler’s diarrhea does not describe ONE disease, but a clinical picture that can be caused by many different pathogens. Unfortunately, most of us have very personal experiences with the problem.

Traveling diarrhea affects 20-50% of all travelers from the so-called 1st to the so-called 3rd world. It is therefore by far the most common symptom of illness on vacation. Even if threatening situations rarely arise, the impact on vacation and relaxation is sometimes serious.

Prevention:

There are many ways of contagion, but with a few, actually self-evident precautionary measures, many of these unpleasant episodes can be avoided. The following are considered “dangerous foods”: tap water, ice cubes and ice cream, milk and unpasteurized dairy products, salads, fruit without skin that can be removed before consumption, raw fish, mayonnaise, cold peels, cold sauces.

Drug prevention with antibiotics: Various substances have been tested in recent years to prevent travelers’ diarrhea. General use is usually discouraged due to possible side effects. For individual travelers with certain underlying diseases or sensitivities, however, medicinal prophylaxis may make sense.

Treatment:

The most important measure in the case of travelers’ diarrhea is to replace the fluid lost through the intestines. In mild cases, drink what you like. If the diarrhea is very severe, you should take isotonic liquids if possible. Such preparations are available in pharmacies (convenient for travel: powder for dissolving). If you don’t have any, you can easily prepare balanced solutions yourself: For every liter of water (from the bottle!) add ½ tsp salt + 2 tsp sugar + ½ tsp sodium bicarbonate (this is table soda, not baking powder, as some brochures say erroneously cited). Symptoms usually improve after 1-2 days.
Medicines that reduce the frequency of diarrhea (“constipating preparations”) can be dangerous in the case of feverish or bloody diarrhea, but in milder cases they save a few days of vacation or a necessary bus ride. Medicines against nausea or abdominal cramps from the first-aid kit can make the first few days easier Self-treatment with antibiotics must be discussed and explained in detail with your doctor before the trip.If you have diarrhea that lasts longer than 4 days, if you have bloody diarrhea or if you have a high fever, you must go to a medical institution.

Cholera is a bacterial infection that causes painless but massive diarrhea. Due to the pronounced loss of fluids in the body, dehydration (dryness) occurs quickly. Vomiting can also occur.

The spectrum of the disease ranges from very mild courses to fatal diseases. Children in particular are particularly at risk due to the high level of fluid loss.

How do you get cholera?

The infection is usually transmitted through water and food contaminated with feces. The disease repeatedly causes major epidemics when sanitation facilities collapse – especially in refugee camps, after natural disasters and floods.

Incubation time:

The incubation period is usually 2-3 days but can be as short as a few hours.

Prevention:

Cholera does not usually pose a risk to the tourist as the conditions under which epidemics occur tend to preclude travel.

However, caution is advised with seafood, in which the bacterium can occur. In order to be infected, such a dish does not have to look or be spoiled!

While an oral cholera vaccine is available, it is not usually recommended for travelers (perhaps when providing relief services in refugee camps or following natural disasters).

Treatment:

The most important therapy is fluid replacement! Drink enough non-alcoholic beverages that you regularly have normal-looking urine (not dark = concentrated, but light). This can definitely require drinking amounts of up to 6-7 liters. In severe cases, infusions may even be necessary.

Antibiotics may shorten the duration of the illness a little and make it more difficult to transmit the infection, but they are only the second most important thing AFTER the liquid!