INFECTIOUS HAZARDS OF INTERNATIONAL TRAVEL

Question 1

INTERNATIONAL TRAVEL AND RISK OF INFECTIOUS DISEASES

Answer 1

• Destinations where accommodation, hygiene, sanitation, water quality and medical care are of a high standard result in few risks to the health of travellers;
• Visiting most major cities and tourist centres pose few serious risks;
• Destinations where accommodation, hygiene, sanitation and medical services are of poor quality or non-existent pose serious risk;

• The epidemiology of infectious diseases in the destination is of importance to travellers;
• Being aware of the occurrence of infectious diseases is important;
• Outbreaks of known or newly emerging infectious diseases are often unpredictable;
• Decisions on the need for certain vaccines or antimalarial prophylaxis.

Question 2

Key factors determining the travel-related risks:

Answer 2

1) Mode of transportation;
2) Destination (local infection epidemiology);
3) Season of travel;
4) Duration of travel;
5) Standards of accommodation, food hygiene and sanitation;
6) Behaviour or the traveller/purpose of travel;
7) Underlying health of the traveller.

Question 3

Traveller behaviors affecting hazards

Answer 3

• Going outdoors in the evenings in a malaria-endemic
areas without taking precautions;
• Swimming in Schistosoma infested lakes;
• Exposure to insects, rodents, bats and other animals;
• Contaminated food/ water is a major risk;
• Unprotected sexual intercourse.

Question 4

RISKS ASSOCIATED WITH POOR FOOD HYGIENE AND SANITATION

Answer 4

Gastroenteritis:
• Worldwide in endemic areas, 1.5 million children die yearly due to infectious gastroenteritis;
• Viral gastroenteritis accounts for ~68% of all gastroenteritis episodes in travellers (military, passengers of board cruise ships, tourists visiting rural areas);
• Causative agents: a) Rotavirus;
b) Norovirus;
c) Astrovirus.

Bacterial gastroenteritis:
a) Campylobacter jejuni;
b) (Enterotoxigenic) Escherichia coli;
c) Salmonella;
d) Shigella;
e) Vibrio cholerae

Question 5

Gastroenteritis presentation:
Diagnosis and treatment

Answer 5

• Anorexia;
• Nausea;
• Vomiting;
• Diarrhoea;
• Abdominal discomfort.

Diagnosis:
• Clinical evaluation; • Stool testing

Treatment:
• Oral or i.v. rehydration;
• Antibiotic in select bacterial cases and if bacteraemia.

Question 6

DESTINATION EPIDEMIOLOGY:VIRAL HEPATITIS

Answer 6

• Destination epidemiology very important;
• Infectious hepatitis still prevalent in areas of developing countries with poor sanitation, crowding and lack of access to clean water;
• Enterically (food and waterborne) transmitted viral pathogens:
1) Hepatitis E;
2) Hepatitis A;

Question 7

HEPATITIS E-INFECTION CHARACTERISTICS

Answer 7

Transmission: faeces (drinking contaminated water or eating contaminated food

Outbreaks: seasonal, often associated with monsoon period

Incubation: 3-7 weeks

Attack rate: 1 in 2

Mortality: <1% but 15-25% in antenatal women
increases with age developed

Severity of disease: increases with age

Vaccines available in developed countries

Question 8

Prevention and Control Measures for Travellers to Hepatitis E Endemic Regions

Answer 8

• Avoiddrinkingwater(andbeverageswithice)of unknown purity, uncooked shellfish, and uncooked fruit/vegetables not peeled or prepared by traveller

Vaccine developed :
In use in China, Nepal,

Question 9

HEPATITIS A-INFECTION CHARACTERISTICS

Answer 9

• Acute,self-limiting infection of theliver;
• Infection may be asymptomatic in children;
• Adults symptomatic;
• Rarely,fulminant hepatitis can ensue;
• Every year there are1.5 million symptomatic cases,

Question 10

HEPATITIS A PREVENTION

Answer 10

Good hygiene
Pre-exposure: active immunisation Vaccine (killed whole virus)
-Travellers to intermediate and high risk areas
-individuals at risk due to sexual behaviour, parenteral drug abuse
Vaccine active within 14 days of first dose
Post exposure: Vaccine (within 7 days) and immunoglobulin HNIG (within 14 days of onset of disease in primary case)

Question 11

ARTHROPOD-ASSOCIATED TRAVEL INFECTIONS

Answer 11

Arthropod: mosquitoes or ticks;

• Mosquito-borne parasitic infection: malaria;
• Mosquito associated viral infections:
1) Dengue types 1,2,3,4;
2) Japanese encephalitis;
3) Murray Valley encephalitis;
4) St Louis encephalitis;
5) West Nile virus;
6) Zika virus;
7) Yellow fever;
8) Chikungunya virus.

Question 12

DENGUE FEVER

Answer 12

• Dengue is transmitted to people by the bite of an Aedes mosquito that is infected with a dengue virus;
• Symptoms of dengue fever are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising);
• Dengue haemorrhagic fever is characterized by a fever that lasts from 2 to 7 days, with general signs and symptoms consistent with dengue fever;
• When the fever declines, symptoms including persistent vomiting, severe abdominal pain, and dispnoea may develop;
• Haemorhage follows leading to failure of the circulatory system and shock, leading to death if circulatory failure is not corrected.

Question 13

ARTHROPOD-ASSOCIATED TRAVEL INFECTIONS
Tick-borne infections:

Answer 13

1) Tick-borne encephalitis (Central European, Far Eastern; Siberian);
2) Kyasanur Forest disease (Alkhumra);
3) Louping ill;
4) Omsk haemorrhagic fever;
5) Powasan;
6) Crimean-Congo haemorrhagic fever.

Question 14

Malaria

Answer 14

212 million estimated cases wandwide
62% mortality rate
429000 deaths due to malaria
92% of all African deaths
Young children under 5

Question 15

Malaria risk assessment for travellers:

Answer 15

Risk differs a lot from region to region even within the same Country

Risk differs from traveler to traveler ( e.g behaviors & circumstances )

Experience and judgement required in risk assessment and decision whether chemoprophylaxis is required;

Travel Clinics, experts in Tropical Medicine good starting point;

Even in low-risk situations, it only takes one bite from an infected female Anopheles mosquito to transmit malaria.

Question 16

MALARIA guidance

Answer 16

• Travel destination is important;
• In areas with limited malaria transmission, it is recommended
that travellers use mosquito avoidance measures only;
• Regions associated with highest relative risk: West Africa and Oceania. In these areas chemoprophylaxis should always be used;
• Regions associated with moderate risk include: parts of Africa, South Asia and South America;
• In countries with significant seasonal shift in temperatures or rainfall, malaria transmission may decrease during the colder or drier months (mosquito avoidance measures).

Question 17

CRIMEAN-CONGO HAEMORRHAGIC FEVER

Answer 17

• Causes severe viral haemorrhagic fever outbreaks;
• Case fatality rate of 10% to 40%;
• Incubation period short (1-3 days);
• Fever, myalgia, neck stiffness, backache, headache, eyes, photophobia;
• Nausea, vomiting, diarrhoea, abdominal pain, mood swings, confusion;
• Bleeding into the skin, mucosa, internal organs;
• Liver failure, kidney failure.

Question 18

VIRAL HAEMORRHAGIC FEVERS

Answer 18

• Viral haemorrhagic fevers (VHFs) refer to a group of epidemic prone diseases that are caused by several distinct families of viruses;
• The term “viral haemorrhagic fever” is used to describe a severe multi-system syndrome (multiple organ systems in the body are affected);
• Characteristically, the overall vascular system is damaged, and the body’s ability to regulate itself is weakened; Symptoms are often accompanied by bleeding which can be life-threatening;
• In Africa: Marburg and Ebola haemorrhagic fevers, Crimean Congo haemorrhagic fever (CCHF), Rift Valley fever (RVF), Lassa fever, Yellow fever

Question 19

RESPIRATORY INFECTIONS ASSOCIATED WITH INTERNATIONAL TRAVEL

Answer 19

• Tuberculosis (TB) is a severe infectious disease caused by various strains of mycobacteria, most commonly Mycobacterium tuberculosis;
• About one quarter of the world’s population is infected with Mycobacteria;
• 10 million people fell ill with tuberculosis in 2017;
• People are infected with TB by inhaling airborne droplets produced
by infectious TB carriers;
• Latent tuberculosis infection (LTBI) carriers are asymptomatic and not infectious;
• The BCG (Bacillus Calmette–Guérin) vaccine provides partial protection against TB.

Question 20

Tuberculosis

Answer 20

Standard treatment of TB consists of a six-month regimen of four first-line drugs (isoniazid, rifampicin, ethambutol and pyrazinamide);

Variants of TB that are resistant to antibiotics are more difficult and expensive to treat, and have higher fatality rates. Their spread is a major challenge to the elimination of TB;

Multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB.

1322 MDR TB in 2016 EU

TB notifications: 58994 in EU

Question 21

RESPIRATORY INFECTIONS ASSOCIATED WITH INTERNATIONAL TRAVEL

• Middle East Respiratory Syndrome Coronavirus (MERS-CoV);

Answer 21

• By September 2018, a total of 2,260 laboratory-confirmed cases of
MERS including 803 associated deaths were reported globally;
• Case-fatality rate: 35.5%; transmission human-to-human;
• 27 countries reported cases of MERS-CoV;
• Symptoms include fever, cough and shortness of breath;
• Pneumonia is common, but not always present;
• Gastrointestinal symptoms, including diarrhoea, have also been
reported;
• Dromedary camels are a major reservoir host for MERS-CoV.

Question 22

RABIES

Answer 22

• Rabies is a vaccine-preventable viral disease which occurs in more than 150 countries;
• Dogs are the main source of human rabies deaths, contributing up to 99% of all rabies transmissions to humans, however any mammal can transmit rabies;
• Infection causes tens of thousands of deaths every year, mainly in Asia and Africa;
• Immediate, thorough wound washing with soap and water after contact with a suspect rabid animal is crucial followed by post-exposure prophylaxis (rabies vaccine and RIG).

Question 23

MONKEYPOX

Answer 23

• Monkeypox is a rare viral zoonotic disease that occurs primarily in remote parts of central and west Africa, near tropical rainforests;
• The monkeypox virus is similar to human smallpox, a disease that has been eradicated in 1980. Although monkeypox is much milder than smallpox, it can be fatal;
• The monkeypox virus is mostly transmitted to people from various wild animals such as rodents and primates, but has limited secondary spread through human-to-human transmission;
• Case fatality in monkeypox outbreaks has been between 1% and 10%, with most deaths occurring in younger age groups;
• There is no specific treatment or vaccine available although prior smallpox vaccination was highly effective in preventing monkeypox as well.