Avoidable infectious diseases


  • African sleeping sickness (Trypanosomiasis)
  • AIDS
  • Chikungunya fever
  • South American trypanosomiasis (Chagas disease)
  • Dengue fever
  • Typhoid fever
  • Hepatitis A
  • Hepatitis B
  • Human papillomavirus
  • Influenza
  • Japanese B encephalitis
  • Meningococcal disease
  • Infantile paralysis (poliomyelitis)
  • Measles
  • Cholera
  • Tick-borne encephalitis
  • Leishmaniasis
  • Lyme disease
  • Malaria
  • Pneumococcal pneumonia
  • Yellow fever
  • Schistosomiasis
  • Sexually transmitted diseases
  • Tetanus
  • Diphtheria
  • Traveler’s diarrhea
  • Chicken pox
  • Rabies
  • Zika virus

Usually spread by infected tsetse flies, which are most common in village areas. Initially, in the first phase of the disease, fever, headache, itching, and joint pain develop. These manifest one to three weeks after the bite. Weeks or months later, a second phase starts with mental confusion, loss of coordination, apathy, and sleep disturbances. Diagnosis is based on localizing the parasite in a drop of blood or lymph node fluid.

AIDS is spread by blood and sexual transmission. People about to go on a long journey should undergo medical and dental tests before travel to avoid needing treatment abroad. Appropriate condom use is efficient not only against AIDS but also other sexually transmitted diseases. It is important to know that all forms of intercourse may carry risks. HIV infection has no symptoms, so seemingly healthy partners may also be a source of infection.

Chikungunya fever is a disease vectored by Aedes mosquitoes; it goes with high fever, headache, nausea, joint and muscle pain. Chikungunya fever is common in tropical areas of Africa and Asia. Its symptoms hardly distinguish it from another tropical disease, dengue fever. As opposed to the latter, however, it mainly affects adults. The disease is very rare to culminate in a fatal outcome, but pain may persist for up to a year after the acute state. Because no efficient treatment or vaccination exists against chikungunya fever, authorities try to prevent it by mosquito control, and recommend that people use mosquito nets and mosquito repellent agents.

A tropical parasitic infection caused by the protozoon Trypanosoma cruzi. It is mostly spread by triatomine bugs. A variety of symptoms emerge during the infection. The early phase of the infection is characterized by no or mild symptoms such as fever, swollen lymph nodes, headache, and sometimes local swelling around the bite site. Eight to twelve weeks later, the chronic phase of the disease ensues, in which 60-70% of patients experience no additional symptoms at all. The remaining 30-40%, however, continue to show symptoms in the 10-30 years after the initial infection.

To prevent the spread of dengue virus, a vaccine was developed in 2015 under the name Dengvaxia, which is not available in Hungary. For disease prevention, the World Health Organization (WHO) primarily recommends reducing the mosquito population and protection against mosquito bites. An infectious disease caused by the dengue virus. Two forms of the disease are distinguished: classic and hemorrhagic dengue fever. The classic form is endemic in tropical areas worldwide, while the hemorrhagic form is present mainly in southern Asia. The dengue virus is spread by mosquitoes including the Asian tiger mosquito. Dengue fever is also called "breakbone fever” because it causes pain so strong that the patient feels as if their bones are being broken. Dengue fever symptoms include fever, headache, skin rashes similar to measles, and muscle and joint pain.

It can occur anywhere in lack of basic hygiene or adequate drinking water supply.

Also known as infectious hepatitis. This disease is mainly prevalent where adequate hygiene conditions are absent. It is spread by contaminated water, food, and direct body contact. Holiday makers staying at luxury hotels are just as susceptible as everybody else. A good example is a 2004 outbreak among German tourists on holiday in Egypt.

The hepatitis B virus is spread by infected bodily fluids (blood, semen, vaginal discharge, saliva). The proportion of affected population is greater in developing countries, which increases infection risks associated with sexual contact or medical intervention. Tattooing, illicit drug use, acupuncture, and piercing may also lead to cases, even in Hungary.

Human papillomavirus (HPV) is an extremely widespread pathogen, which causes abnormal cell division, rampant proliferation in epithelial areas such as hands, feet, vocal cords, oral cavity, and sexual organs. Their carcinogenicity classifies them into high (15-20 carcinogenic types), medium and low risk categories.

Cervical intraepithelial neoplasia is another form of HPV infection; it is the earliest form of cancer limited to the epithelial tissue. It is still unknown what proportion of CIN is able to deteriorate into de facto cancer, but there is wide consensus that the condition is to be taken seriously. CIN is most commonly discovered during cancer screening when the cytological finding is a P3 or possibly P4.

Influenza is a viral disease characterized by fever, rhinorrhea, coughing, headache, feeling unwell, and swollen mucous membranes in the nose and airways. Like pathogens of other respiratory infections, influenza viruses spread via droplet infection, i.e. through droplets of respiratory discharge produced by coughing, sneezing, or talking.

A viral disease vectored by Culex mosquitoes and mostly found in Asia and the western area of the Pacific Ocean. No causal treatment is available. The disease course is that of an atypical fever. Permanent partial loss of cognitive and other neurological functions is frequent after recovery. Vaccination is available. Non-specific protection is possible by using mosquito repellents and nets.

Spreads via droplet infection but requires a tight contact for infection to develop. Sporadically occurs in developed countries as well. It is endemic in Central Africa and the Arab Peninsula; vaccination is recommended for travelers to these destinations. Mandatory for pilgrims departing to Mecca.

Infantile paralysis has been eradicated in most of the developed and developing world, but it is still found in a few regions. There is no efficient treatment against the virus, which highlights the importance of prophylaxis, i.e. vaccination.

A highly contagious infectious disease of global presence; its features include a febrile, catarrhal initial stage followed by an erythematous phase. Measles used to be one of the most common childhood infectious diseases in Hungary as well. Since the time measles vaccination became mandatory for all children, the disease has virtually disappeared from everyday Hungarian family life. Similarly to developed countries where the vaccine is widespread, only sporadic cases of measles can be found. Groups currently exposed to a potential risk include those of adult age and health care workers.

Cholera is not typically a threat for travelers as long as they maintain appropriate food safety measures. Tourists are therefore not recommended to take up cholera vaccination unless they are in a high-risk situation such as members of humanitarian organizations working in disaster-struck areas, refugee camp workers, or staff serving on board marine ships.

The disease is common in the whole of Central-Eastern Europe. Also known as viral meningoencephalitis, this is the least common but most severe infection vectored by ticks. The disease starts with indistinct respiratory symptoms and fever after an incubation period of 7 to 14 days after the bite. Frequent symptoms also include a headache and vomiting. The illness of the nervous system continues a few days later with another febrile period after a transient nonfebrile phase. Loss of consciousness and paralysis may occur, which might even lead to death.

Phlebotomus flies – colloquially known as sand flies – vector the pathogens among animals (rodents, canines) and humans. The disease form affecting the skin and mucous membranes has an annual 1-1.5 million, and the form causing visceral abnormalities, an annual half a million new cases. The prevalent infection case count is estimated at 12 million. About 90 countries are affected to any extent, and the entire Mediterranean region is considered to be an infected area.

A multifaceted disease spread by ticks. No vaccination exists; various manifestations can be treated by lengthy courses of antibiotic therapy. Non-specific protection is also possible by using tick-repellent preparations and by rapid removal of attached ticks.

Malaria is a disease caused by pathogens spread by female Anopheles mosquitoes. Regarded as a global endemic disease, it mostly occurs in tropical areas. Annual new cases amount to about 350-500 million, of which more than a million are fatal; and in Africa, annual disease mortality is as high as 25% in the pediatric population under 5 years of age. Factors explaining the high mortality include an ever-increasing level of drug resistance as well as growing tolerance against insecticides in mosquitoes.

The disease is caused by four different unicellular parasite species of the Plasmodium genus: Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium falciparum. Infection by the latter is associated with the most severe disease course. The key symptom of malaria is fever, usually a typical febrile fit accompanied by chills.

The bacterium Streptococcus pneumoniae causes bronchopneumonia at a moderate frequency in babies and the elderly, while it mostly generates classic lobar pneumonia in bigger children and adults. Vulnerable patient groups (people with diabetes, splenectomy, hereditary/acquired immune deficiency, renal, cardiac, hepatic insufficiency, etc.) are recommended to receive a pneumococcal vaccine.

A disease spread via mosquito bites. Vaccination is mandatory for travelers to Africa and tropical areas of Central and South America. Countries involved check for the presence of vaccination and refuse entry without valid vaccination documents.

The disease spreads through contact with parasite-infested water. Larvae of the parasites emerge from infected freshwater snails. The disease is especially common in children in developing countries since they are more likely to play in infested water. Other risk groups include farmers, fishermen, and those who use infested water during their everyday work. The symptoms are, among others, lower abdominal pain, diarrhea, and bloody stool or urine. Patients with a longer history of infection may develop liver damage, renal insufficiency, infertility or urinary bladder cancer.

Some infectious diseases are transmitted through sexual contact. Up until the last third of the 20th century, these were referred to as genital diseases; however, more recent studies revealed the existence of many microbes that, even though transmitting sexually in a natural way, cause illnesses to other body parts rather than genital organ disease. The disease group includes: syphilis (bad blood, Cupid’s disease, French disease, lues), gonorrhea (the clap), trichomoniasis, non-gonorrheal urethritis (NGU), acute urogenital chlamydia, genital herpes simplex, genital warts, HIV infection, Hepatitis B virus infection (HBV), Hepatitis C virus infection (HCV), HPV virus infection.

A disease with a frequent fatal outcome, mostly affecting muscular motor nerves. Its pathogenic agent is the anaerobic bacterium Clostridium tetani. Its spores are ubiquitous in street dust or garden earth. Once spores enter an open wound, the infection is complete. The bacterium multiplies in places isolated from air and oxygen, and produces toxins which damage motor nerves, thereby causing paralysis and spasms, as well as the heart. Spasms occur in the jaw and elsewhere in the body. The infection is vaccine-preventable – the manifestation of the disease can be blocked by prophylaxis. Childhood vaccine efficacy deteriorates by adulthood; re-vaccination is recommended.

Caused mostly by the infection of earth-contaminated wounds, the disease is globally present. Everybody receives a full vaccination series against tetanus in childhood; therefore, it is recommended for those with more than ten years since their last tetanus shot.

Diphtheria is one of the diseases all babies are vaccinated against. Re-vaccination every ten years is necessary for adults. Vaccines against tetanus and diphtheria are administered in a combined shot efficient for ten years.

Defined as passing mushy stool at least twice as often as usual. It is commonly associated with abdominal discomfort, lower abdominal cramps, bloating, intense intestinal motility, urge to defecate, fever, and weakness. The onset is sudden (either during travel or after returning home), and comes with 4-5 soft stools a day, which resolves on its own in 3-4 days. About 10% of cases last longer than a week, with 1% drawing out for a month or longer, depending on the pathogen. The most common causal agent is enterotoxigenic Escherichia coli, which accounts for about 80% of traveler’s diarrhea. Other cases are often caused by pathogenic bacteria such as those of the Salmonella, Shigella, and Campylobacter genera. Parasites (worms) account for about 5% of traveler’s diarrhea, while viruses cause an even smaller proportion of cases.

Chicken pox is one of the most common and most contagious childhood droplet infections, which most unvaccinated people undergo while still in their childhood. Its primary onset period is between three and ten years of age, with most cases occurring before 15 years of age at the latest. Breastfed babies are relatively more protected because they enjoy immunity through breast milk from the mother. Complications may develop in a tenth of cases, and are more likely in adulthood. Vaccination is highly recommended for risk group members and couples contemplating pregnancy.

Vaccination against rabies is not mandatory for travelers. The vaccine is recommended when infection risks are elevated, e.g. for hunters, animal attendants, and people moving around on bicycles or motorcycles. Children are also a high-risk group because they touch animals more often but don’t always tell their parents when they do. In addition to bites and scratches, possible pathways of infection include saliva from a rabid animal ending up on sore skin or mucous membrane (eyes!). Not just foxes, dogs and cats, but all mammals including rodents and bats can be infectious!

An infectious virus spread by insects. The disease course is typically of a mild nature and non-fatal; however, pregnant women’s fetuses are especially vulnerable as the virus may cause a severe developmental disorder called microcephaly (small head) as well as other neurological complications, in particular, Guillain–Barré syndrome. The virus may spread via transfusion of infected blood, sexual contact, and transmission from an expectant mother to a fetus during pregnancy. According to current knowledge, infected persons become immune. No antidote or vaccine exists either for prophylaxis or treatment so far. Women in a number of South-American countries were advised to temporarily avoid pregnancy. Pregnant women living in other areas are advised against visiting warm climate countries where an outbreak has been registered.

Protection against mosquitoes is of the greatest importance; travelers in affected regions should wear long-sleeve shirts and pants, headwear, and sleep sealed around by mosquito nets.