Essential vaccines for travelling to exotic countries

Vaccination is an essential stage before travelling to an exotic destination. Above all if the traveller is interested in visiting less touristic places. In this article discover which vaccines are the most recommended.

Currently recommended:

Vaccines against Hepatitis A and Typhoid Fever for any traveller going out of Europe, Japan, USA-Canada or Australia, especially if going away from the cities

Vaccine against Rabies is also recommended for these countries, but especially for Asian and African countries and the triangle between Honduras, Guatemala and El Salvador.

Vaccine against Yellow Fever, for travellers to tropical parts of Africa and America, including those headed to the Brazilian jungle, Peru or Bolivia and to destinations like Senegal or Kenya, which receive more and more international travellers.

Apart from these more general vaccines, it is also very important to check up-to-date information about existing illnesses and infections in each specific area to be visited, as there could be other preventative measures which are recommended.

Another tool of great help to the traveller are mobile phone applications available with geolocalization of medical specialists, which, in case of emergency, allow the traveller to find the nearest doctor.

Hepatitis A

Hepatitis A is a hepatic illness caused by the Hepatitis A virus (HAV). Affects the liver causing moderate to serious loss of use.

Risk-free area
Area of risk

It’s transmitted: Consuming contaminated food or drinks.

Direct contact with infected people.

Affected annually:
Approx.

1.4 million people worldwide

Linked to: Absence of safe drinking water, deficient sanitation and poor personal hygiene.

Improvements in sanitation, food safety and vaccination are the most effective means to tackle Hepatitis A.

Symptoms

The incubation period for Hepatitis A is usually between 14 and 28 days.

The symptoms of Hepatitis A can be moderate or serious and include fever, general discomfort, loss of appetite, diarrhea, nausea, abdominal pains, darkening of the urine and jaundice (a yellowing of the skin and whites of the eyes). Each infection doesn’t always show all the symptoms.

Who is at risk?

Among the risk factors we should mention the following:

  • Deficient sanitation
  • Lack of safe drinking water
  • Injectable drugs
  • Living with an infected person
  • Sexual relations with a person with acute HAV infection
  • Travelling to areas where the virus is endemic without prior immunization

Diagnosis

Cases of Hepatitis A are clinically indistinguishable from other types of acute hepatitis virus. Diagnosis is through a blood test and the detection of antibodies IgM and IgG specifically aimed at fighting HAV.

Treatment

There is no specific treatment for Hepatitis A. The symptoms diminish slowly, over a period of several weeks or months. The treatment is concerned with the well-being and nutritional balance of the patient, included the re-hidration after vomits and congestion.

Prevention

Improvements in sanitation, food safety and vaccination are the most effective means to tackle Hepatitis A.

A month after having received a single dose of the vaccine, almost 100% of people will have developed protective levels of antibodies. Even after exposure to the virus one dose of the vaccine within the two weeks after being in contact with the virus, has protective effects.

Rabies

Rabies is a zoonosis (a disease transmitted to human beings by animals) caused by a virus which affects domestic and wild animals, and is spread to people through contact with infected saliva, through bites or scratches.

Risk-free area
Area of risk
Area of high risk

Treatment:

15 million people worldwide

receive prophylactic treatment with the vaccine after exposure. In this way hundreds of thousands of deaths from rabies are prevented.

Affected annually:

50,000 deaths worldwide

Mainly in Asia and Africa

Prevention: An illness which is preventable through vaccination and affects more than 150 countries and territories.

Immediate cleansing of the wound and immunization in the hours after contact with the supposedly rabid animal can avoid the illness appearing and prevent death.

Symptoms

The incubation period of rabies is usually between 1 and 3 months, but it can vary between less than a week and more than a year. The first signs are a temperature, which is often accompanied by pain or paresthesia (an unusual or unexplained tingling, itching or burning sensation) at the point of the wound.

As the virus spreads through the central nervous system it produces a progressive inflammation of the brain and the spinal cord, ultimately ending in death.

The illness can take two forms. The first, the furious form of rabies, with signs of hyperactivity, excitement, hydrophobia and, sometimes, aerophobia, with death occurring a few days later due to cardiac arrest.

The other form, paralytic rabies, accounts for about 30% of the human cases and takes a less dramatic generally more prolonged course than the furious form. The muscles gradually become paralyzed, starting with those closest to the bite or scratch. The patient slowly falls into a coma, ending in death.

Diagnosis

There are no tests to diagnose a rabies infection in humans before the appearance of clinical symptoms, and unless there are specific signs like hydrophobia or aerophobia, the clinical diagnosis can be difficult to ascertain.

Transmission

People become infected through a deep bite or scratch from an infected animal. Dogs are the main hosts and transmitters of rabies.

Bats are the main source of infection in the cases of rabies fatalities in the United States, Canada and Latin America. Rabies in bats has recently become a threat to public health in Australia, and Western Europe.

Post-exposure treatment

Post-exposure prophylaxis consists of:

  • Local treatment of the wound, beginning as soon as possible after exposure;
  • Application of a strong, effective anti-rabies vaccine according to WHO recommendations;
  • Administration of anti-rabies immunoglobulin, where appropriate. Effective treatment immediately after exposure can prevent the appearance of symptoms and death

Local treatment of the wound: Recommended first aid consists of washing the wound immediately and thoroughly for a minimum of 15 minutes with water and soap, detergent, povidone-iodine or other substances which kill the rabies virus.

Yellow fever

Yellow fever is a severe hemorrhagic viral illness, transmitted by infected mosquitos. The term ‘yellow’ refers to the jaundice that appears in some patients.

Risk-free area
Area of risk

Affected areas:

Tropical areas of Africa and Latin America, with a population of more than

900 million inhabitants.
50%

of serious cases can lead to death if not treated

200,000

cases of yellow fever

30,000

deaths (90% of them in Africa)

Treatment:

There is

NO cure

The treatment is symptomatic and consists of easing the symptoms and maintaining the well-being of the patient.

Prevention:
Vaccination is the preventative measure.

It is safe, affordable, very effective, and a single dose is enough to provide immunity and protection for life, without the need for a booster. It offers an effective immunity to 99% of people vaccinated/30 days..

Signs and symptoms

Once the virus has been contracted and the 3 to 6 day incubation period has passed, the infection could go through one or two phases. The first, severe, often causes fever, myalgia with intense back ache, headaches, shivering, loss of appetite, and nausea or vomiting.

Subsequently, the majority of patients get better and the symptoms disappear in 3 or 4 days.

However, 15% of patients enter a second, more toxic, phase 24 hours after the first symptoms appear. The high fever returns and different organ systems are affected. The patient quickly becomes jaundiced and complains of abdominal pains and vomiting. There can be oral, nasal, ocular or gastric hemorrhage, with blood in the vomit and faeces. Kidney function deteriorates. Half the patients who enter the toxic phase die within 10 to 14 days and the rest recover without serious lesions on their organs.

Diagnosing yellow fever is difficult, above all in the early phases. It can be confused with other hemorrhagic fevers and other illnesses. Specific antibodies to fight the virus can be detected through blood tests.

Populations at risk

There are 44 countries in Africa and Latin America where the disease is endemic, with a total of 900 million inhabitants at risk.

In countries free of yellow fever there is a small number of imported cases. Although no cases have been recorded in Asia, the region is a risk zone because it has the necessary conditions for transmission.

Transmission

The yellow fever virus is an arbovirus of the Falvivirus genus and its main vectors are mosquitos, which transmit the virus from one host to another, mainly between monkeys, but also from monkey to human and from one person to another.

There are three transmission cycles:

  • Jungle yellow fever: In the tropical rain forests yellow fever affects monkeys, which are infected by wild mosquitos. In turn the monkeys transmit the virus to other mosquitos which feed off their blood and the infected mosquitos bite people who go into the jungle, causing occasional cases of yellow fever.
  • Intermediate yellow fever: In the humid or semi-humid zones of Africa there are small-scale epidemics. The semidomestic mosquitos (those that develop in the jungle and move towards houses) infect both monkeys and humans.
  • Urban yellow fever: When infected people bring the virus to areas of high population density with a large number of mosquitos where people are not immune, this creates large epidemics. The infected mosquitos pass the virus from one person to another.

Treatment

There is no specific treatment for yellow fever. Only support measures can be used to fight the fever and dehydration. The associated bacterial infections can be treated with antibiotics. The support measures can improve the outcome of the serious cases, but they are rarely available in the poorest areas.

Prevention

1. Vaccination
Vaccination is the most important measure to prevent yellow fever. The vaccine against yellow fever is safe and affordable, and provides effective immunity in 80-100% of those vaccinated after 10 days, and immunity in 99% after 30 days. A single dose is enough to provide immunity and protection for life, without the need for a booster.

2. Mosquito control
In some situations, mosquito control is essential until vaccination takes effect. The risk of yellow fever transmission in urban areas can be reduced by removing potential breeding grounds for mosquitos and adding insecticide to the water where they develop in their earliest stages.

Early warning and response to epidemics

The rapid detection of yellow fever and the immediate response with emergency vaccination campaigns are essential in controlling outbreaks. However, underreporting is worrying; it is estimated that the true number of cases could be 250 times greater than the number of cases reported at present.

In addition, the number of cases of yellow fever has increased in the past two decades, due to the fall in immunity among the population, deforestation, urbanization, movements in population and climate change.

Typhoid Fever

Infectious disease caused by the bacteria Salmonella typhi (Eberth’s bacillus) or Salmonella Paratyphi A, B or C, bacterias of the Salmonella genus.

Risk-free area
Area of risk
Area of high risk

Transmission:

Its reservoir is the human body, and it is passed on through the faecal-oral route via water or food contaminated with faeces.

Considered a serious public health problem by the WHO, there are between

16 and 33

million cases/year

216,000

deaths/year worldwide

Mortality has been reduced to

1% of the cases

thanks to the use of antibiotics like ampicillin, chloramphenicol, trimethoprim/sulfamethoxazole and ciprofloxacin.

Affected areas:

The illness continues to be present in developing countries, mainly in Southeast Asia, Central Asia, some South American countries, and Sub-Saharan Africa.

Symptoms

The incubation period usually lasts between 10 and 15 days. In this period there are disruptions of the general state, starting with a phase of bacteremia accompanied by a fever which usually increases progressively, reaching 39-40ºC. Once the fever reaches this level, it stays there, and is accompanied by headaches, stupor, roseola on the stomach, swelling of the nasal mucous membrane, a dry or ‘furry’ tongue, mouth ulcers on the palate, and sometimes hepatosplenomegaly and diarrhea.

The illness can develop and the patient get better in a period of two weeks or even last longer with localized symptoms from the fifth week. If the infected person is not given the appropriate treatment, it could lead to serious complications, like hemorrhage and intestinal perforation and even septic shock.

People who have had typhoid fever have a certain degree of immunity. However, while this doesn’t protect them from possible reinfections, it does mean that if they should become reinfected, it will be milder.

Transmission

The bacteria enters the human body through the digestive tract, reaching the intestine and finally arriving in the blood. Here the virus causes a bacteremia phase a week after contracting the illness. In the subsequent phase various organs are affected, causing inflammatory and necrotic phenomena, due to the release of endotoxins in the body. Finally, the salmonella is expelled through faeces.

Due to the transmission process, early detection is essential, so that clothes and crockery and cutlery used by the patient can be washed separately to avoid further infections.

Treatment

The death rate has been reduced in developed countries thanks to the use of antibiotics like ampicillin, chloramphenicol (most widely used), trimethoprim/sulfamethoxazole (also known as cotrimoxazol) and ciprofloxacin, bringing the death rate down to 1% of cases.

However, Salmonella Typhi is becoming resistant to these drugs, which is why the use of other antibiotics, such as Fleroxacin is being considered.

All these drugs reduce the severity of complications and the duration of the symptoms of typhoid fever, although recovery can take several months.

In any case, treatment must be given under medical supervision.

Prevention

Correct sanitation and hygiene are the two most important measures for preventing infection. Some other key measures to prevent typhoid fever are; appropriate handling, storage and cooking of food, boiling water, treating water and bins.

At present there are two vaccines recommended by the WHO: the oral vaccine Ty21a and the injectable Vi capsular polysaccharide (ViCPS). These two vaccines protect between 50 and 80% of cases and are highly recommended to all those people who travel to countries and regions where infection is endemic.