Travel Related Illness With A Focus On Infections

Introduction
As air and sea travel become more convenient and affordable, we are seeing more travellers venture to more remote and exotic locations. The draw of new, unfamiliar and exciting cultures, landscapes and unique experiences continue to lure visitors from developed countries to less developed ones. The exposure to infections endemic to these less developed countries against a backdrop of suboptimal and often unsafe medical care in these countries imposes a significant risk of serious infections to travellers. In the future, our journeys may include space and deep sea travel. These may result in new and unusual medical conditions as yet unknown to us today. But you only live once …….

Epidemiology
Travel related infections may be divided into the following categories :

  1. Common infections related to the stress of travel and poor sleep/jetlag eg common respiratory infections, urinary tract infections, skin diseases etc
  2. Acquiring diseases which are endemic to the travel destinations : Dengue, Chikungunya, Zika, parasitic diseases, endemic fungal diseases, malaria, etc
  3. Infections due to exposure to poor environmental hygiene and sanitation such as foodborne and water borne diseases, skin infections, etc
  4. Nosocomial infections related to medical tourism: acquiring infections as a result of seeking medical care overseas and they include wound infections from poorly done surgery, HIV, Hepatitis B & C from blood transfusion and organ transplantation, etc. In addition, the infections may involve multi-drug resistant bacteria (NDM bacteria , drug resistant TB, etc)
  5. Immunocompromised patients traveling overseas are at a higher risk for all types of infections due to their poor immune status
  6. Infections related to inflight or cruise ship confinement. These are usually airborne or foodborne infections from a common source transmitted by being in close contact in a confined space for extended periods ; or food/water contamination from a common source served to a large group of people. Other reported infections include SARS, influenza, TB, gastroenteritis, food poisoning etc
  7. Infections related to specific activities eg. Sexually transmitted infections and sex tourism, disease outbreaks when performing disaster relief work eg refugee camps, health workers exposed to Ebola epidemics etc.

The traditional group tour travel has been increasingly replaced by free independent and intrepid travellers venturing out to less trodden paths and remote areas. The young are more adventurous and more curious than ever. Adventure travel of course comes with its attendant risks including more accidents, injuries and infections.

Clinical Presentation
Depending on the incubation period of the disease, travel related infections can present during the period of the travel and up to a few weeks after the traveller has returned to the home country. Some viruses have long incubation periods and symptoms may not manifest until weeks or months later eg. Hepatitis B, HIV, Hepatitis E, Hepatitis C, etc.

The following clinical syndromes are commonly seen :

  1. Fever of unknown origin
  2. Skin rashes or skin lesions
  3. Sexually transmitted infections
  4. Respiratory Syndrome with cough or respiratory distress
  5. Gastrointestinal Syndrome with diarrhoea ( with or without blood ), nausea, vomiting or crampy abdominal pains/ bloating
  6. Neurological Syndrome : Meningitis, Encephalitis
  7. Rarely, gravely ill with multisystem involvement – can be seen in leptospirosis, SARS, typhus/rickettsial infections, meningitis, etc

Diagnosis
If travel related infections are suspected, history taking is very important in the evaluation. A detailed history of the travel itinerary, places visited, participation in activities, food consumed, types of prophylaxis taken including pre-travel immunisation or malaria prophylaxis used should be elicited in order for a proper risk assessment to be made.

The physical examination is important especially when assessing for skin lesions, rashes, presence of jaundice, lymph gland enlargement and organomegaly. There are pathognomonic skin lesions like cutaneous larva migrans, typical Dengue rash, rickettsial rash, eschar, cutaneous leishmaniasis, etc where the clinical appearance is enough to make a diagnosis.

Other types of infections that present as “fever of unknown origin” will usually require numerous laboratory investigations including :

  • Blood culture (e.g for typhoid fever)
  • Blood film for malaria (if there was travel to malaria endemic zones)
  • Viral Antigen or serology tests if relevant eg Chikungunya, Dengue, Zika, etc
  • Other serologies eg Leptospiral antibody, Rickettsial serology, Brucella, etc
  • Hepatitis testing if jaundice
  • STD (sexually transmitted diseases including HIV)testing if indicated
  • Specific targeted testing for filaria, fasciola, echinococcus, etc
  • Stool tests for parasites and stool culture for bacteria and multiplex testing for viruses, bacteria and parasites
  • Radiological imaging may be required to diagnose liver abscesses, lung infections, meningitis and brain abscesses, etcSometimes, may require invasive tests like lumbar puncture and biopsy of lesions

Treatment
Treatment depends on the diagnosis. If the correct diagnosis is made, treatment usually results in rapid response and cure.
Delay in diagnosis can result in fatality especially for disease like malaria ( Falciparum type ) and leptospirosis ( severe type : Weil’s disease ), meningitis and encephalitis.

Most viral diseases are self limiting and does not require active treatment.

Dengue can sometimes result in Dengue Shock which carries a high mortality rate

Chikungunya is a mild infection in most people but can be associated with a debilitating arthritis/arthralgia in predisposed individuals. They are managed with anti-inflammatory agents and painkillers. In severe cases, steroids may be required to control the arthritis.

Prevention
In general, most travel infections can be anticipated, prevented or prophylaxis may be instituted if the traveller has done his homework and taken the appropriate precautions. If the traveller has a significant pre-existent illness, it may be prudent to see your regular doctor for a pretravel evaluation to ensure that you are fit for the type of travel you are embarking on. This is especially important for the immunocompromised patients.

For travel to remote areas with difficulty of access to reasonable medical care, it is best that all precautions be reviewed from 2-6 weeks before travel andprophylaxis should be taken before travelling. Remember to buy comprehensive medical insurance including medical evacuation insurance to a tertiary medical care centre or back home in case of serious illness or complications.

You are advised to see your doctor 4-6 weeks before your travel because :

  1. Some vaccinations require a course or series before they are effective eg Hepatitis vaccine is given at 0,1,6 months schedule
  2. Vaccinations work best about 2 -4 weeks after the injection and peak antibody levels are achieved about one month post vaccination
  3. Multiple vaccines may not be given all at once, multiple live attenuated vaccines should be given simultaneously or one month apart
  4. Some medical conditions may need time to be optimised before travel eg post chemotherapy neutropenia recovery may take a few weeks to normalise
  5. Malaria pills may be started one or two week before travel (Mefloquine)
  6. Yellow Fever vaccine is only valid 10 days after vaccination as regulated under the International Health Regulation as it takes time to make protective antibodies

Please see the section on travel vaccinations under “Adult Immunisation” for further details.

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