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By Dr Jennifer Sisson

The lush European countryside in summer is renowned for emerald green meadows and the sound of cowbells, but there are many visitors, including Australian tourists, who are oblivious to a tiny, but potentially dangerous, insect that may be lurking in the grass – ticks, and they are capable of transmitting a number of diseases.
This year, popular tourist destinations such as Switzerland and Germany have already experienced a rise in the rates of infections transmitted by ticks, particularly tick-borne encephalitis (or TBE). Switzerland has recorded some 150 TBE cases since the beginning of 2018, while in Germany, when compared to last year, TBE case numbers have also increased and they correlate with the high tick activity observed by researchers in the country’s south (a hot spot for tick activity). More and more travellers from non-infected countries are visiting at-risk areas and undertaking adventurous and off-the-beaten track travel, so there is a very real need for travellers to be aware and prepared for this rare, but high consequence, disease.

About TBE

Tick-borne encephalitis is caused by a virus that is transmitted to humans by the bite of infected ticks (Ixodes persulcatus and Ixodes ricinus species) or as a result of consuming contaminated unpasteurised milk products. There are three related sub-types: European, Siberian and Far-Eastern and they are all caused by a flavivirus, a genus of viruses that includes dengue fever, Zika virus, yellow fever and Japanese encephalitis, all of which are transmitted to humans and animals by insects such as mosquitoes and ticks. The virus acts by attacking the human central nervous system and it’s the most common tick-borne infection in Europe and Asia, affecting at least 27 European countries and several Asian nations. Within the risk areas there’s considerable variation in both the prevalence of the virus in the tick species, and in the pervasiveness of infected ticks.

Symptoms of TBEV infection

The incubation period of tick-borne encephalitis virus (TBEV) infection ranges from two to 28 days, with an average of seven to 14 days; however if the virus is ingested, that drops to around 3 to 4 days. As with other illnesses caused by a flavivirus, only a small number of infections actually lead to symptomatic disease – around three-quarters of TBE infections produce no symptoms. For those that do, there is often a two-part progress: a non-specific illness with fever, muscle aches and headache, followed by the most recognised clinical manifestation, neurological disease such as meningitis, encephalitis and encephalomyelitis.
The severity of the disease depends on the virus sub-type: the Far-eastern sub-type generally follows a one-stage illness with death rates of up to 35 percent, while the European and Siberian sub-types tend to produce a less severe illness, with fatality rates of 0.5–2 and 1-3 percent respectively. However, also associated with the European sub-type is the incidence of age-related complications: adults aged over 40 are more likely to develop severe disease and if they are over 60 years of age, the incidence of death or lasting effects increases again.

Risk of TBE infection in travellers

Just how many travel-associated TBE cases there have been is unknown, and the reporting of infections in tourists is likely to be underestimated, particularly as the illness’ average incubation period is two weeks, meaning clinical symptoms are likely to occur when travellers return home.
The risk of contracting a TBE infection depends on the season of travel (ticks are active during the warmer months of April to November) and the amount of unprotected outdoor exposure (activities planned in forested areas where ticks may live, usually with grass, bushes and shrubbery and up to 1,500 metres in altitude). The activities that constitute the highest risk for travellers are camping, hiking, biking, mushroom- and berry-picking, mountaineering, horse riding (a popular past-time for tourists in Mongolia) and playing golf. The first imported case of TBE in Australia, as reported in a study by Chaudhuri et al (2013), concerned a traveller returning from Russia and it highlighted the difficulty in making a definitive diagnosis because of its rarity and the unavailability of laboratory testing.

Prevention of TBE

Bite avoidance measures
The advice is to avoid tick-infested areas and protect yourself against tick bites by dressing appropriately (long sleeves and long trousers tucked into socks) and use an effective insect repellent. Repellents containing DEET, Citriodiol or picaridin can be applied directly on exposed skin, while clothing and camping gear can be impregnated with a contact insecticide such as permethrin. Following outdoor activities, clothes, hair and skin should be routinely examined for ticks and if found, they should be removed promptly. Additionally, consumption of unpasteurised milk products should be avoided.

Vaccination
Besides preventing tick bites, immunisation is the best way to protect against TBE. In Australia, a vaccine (Ticovac) is available through the Therapeutic Goods Administration’s Special Access Scheme but we advise you to contact your travel health practitioner well in advance of travel as more than one dose is needed to offer protection.

References:

1. Bogovic, P. & Strle, F. (2015) Tick-borne encephalitis: A review of epidemiology, clinical characteristics and management
2. Haditsch, M. & Kunze, U. (2013) Tick-borne encephalitis: a disease neglected by travel medicine. Travel Medicine and Infectious Disease (11) 295 -300.
3. Heinz, F.X, Stiasny, K., Holzmann, H., Gric-Vitek, M., Kriz, B., Essl, A. & Kundi, M. (2013) Vaccination and tick-borne encephalitis, Central Europe.
4. US Centers for Disease Control and Prevention (CDC) Travelers Health – Chapter 3. Infectious Diseases related to Travel (Tick-borne encephalitis).
5. Rendi-Wagner, P. (2004) Risk and Prevention of Tick-borne Encephalitis in Travellers.
6. Chaudhuri A., & Růžek D. (2013) First documented case of imported tick-borne encephalitis in Australia.
7. The European Centre for Disease Control, Factsheet about tick-borne encephalitis (TBE) https://ecdc.europa.eu/en/tick-borne-encephalitis/facts/factsheet
8. The Australian Immunisation Handbook 10th edition 3.2 Vaccination for international travel

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Right now it’s the rainy season in many regions of Asia popular for travellers, such as India, Thailand, Vietnam, Cambodia and Laos.You may not want to hear this if you’re heading over there for a holiday soon but … when the rainfall increases, so do the activities of biting mosquitoes.

Disease vector

Mozzies. They’re not just pesky insects; they cause diseases that sicken or kill millions of people worldwide each year. We know that it’s the female mosquito that bites us, requiring a blood meal to incubate her eggs. And of the species that prefer meals from vertebrates (including humans), some bite at night (dusk to dawn) while others feed during the day (dawn till dusk).

The insects are drawn to us by the carbon dioxide we exhale and our body heat, but how they decide which individual to zoom in on is dependent on the preference of the particular mosquito species. It can be genetics, a colour tone (dark), or an odour, for instance, from beer drinkers, lactic acid found in sweat, pregnant women, some skin bacteria or feet that are ‘on the nose’. Interestingly, one study found that Anopheles (malaria-transmitting) mosquitoes were more likely to be drawn towards humans who had malaria. This would of course enhance the risk of onward transmission of the malaria parasite to the next person the mosquito feeds from.

If you’re travelling to Asia at this time of year it’s wise to get the right advice by speaking to a travel health practitioner. That way you can learn about any potential risks for your itinerary, in particular mosquito-borne infections which are likely to be more prevalent due to the ideal breeding conditions presented by the rainfall. The doctor will take you through the best ways to prevent infection, which includes when the disease vectors (mozzies) are active: malaria- and Japanese encephalitis virus-transmitting mosquitoes fall into the night-time biting category, while those that transmit dengue fever, chikungunya and Zika virus are more active in daylight or if the area is brightly lit.

 Home-grown infections

They’re not very common fortunately, but we do hear tales of dengue fever or malaria infections in Australian travellers returning home. (So far this year over 350 people have contracted dengue and 147 malaria.) Of course mosquito-borne illnesses can also be caught here without leaving the country. Last year was a particularly bad one for Ross River virus infections, with nearly 7,000 casesover 5,000 of those from Qld, Victoria and NSW. We also have Barmah Forest virus, Murray Valley encephalitis and Kunjin virus, among others. The chain of infection is mostly between animal or bird reservoirs and mosquitoes but if they’re unlucky, and unprotected by clothing and repellents, humans can become sick when bitten by an infected mosquito.

Keep your guard up and avoid bites

It takes just one bite from an infected mosquito for you to get sick. And, it’s especially easy to let your guard down when you’re on holidays.
Until effective vaccines are available, we have to rely on 
avoiding mozzie bites by:
- Using an
effective insect repellent containing DEET, Picaridin, or Citriodiol (PMD).
- Getting rid of water-holding containers around your accommodation where mozzies can breed, and
- Either going inside around dawn and dusk or changing into long sleeves, long pants, and shoes and socks (the clothing can be treated with a contact insecticide,
permethrin).
- Sleeping under a
permethrin-treated bed net if your room is not screened or air-conditioned. 

Don’t become another travel statistic.
Before you fly, call Travelvax Australia’s travel health advisory service on 1300 360 164 (toll-free from landlines) to learn more about the mosquito-borne diseases at your destination. You can also arrange a consultation to get recommended vaccinations and personalised illness prevention advice from medical professionals with an interest in travel medicine.

Image: Dreamstime, Oleg Doroshenko.

Take condoms with you, and use them. That’s the message to young Aussie backpackers following a study showing high rates of unsafe sex with new partners among young international travellers heading to full moon parties in Thailand.
British researchers say high-risk sex among young travellers attending the hugely popular all-night beach parties on Koh Tao and Koh Phangan is fuelling the global spread of sexually transmitted infections (STIs) such as chlamydia, HIV and gonorrhoea (including antibiotic-resistant strains like Neisseria gonorrhoea) along with unplanned pregnancies.

What the study found

In a survey of 1238 young single travellers - including 72 Australians – visiting Thailand, the researchers found that overall almost 40% had sex with a new partner. Of these, 37% had unprotected sex.
The survey also revealed:
- UK and Swedish backpackers were most likely to have unprotected sex, at rates of 49% and 46% respectively.
- Australians had a 30% rate of unprotected sex.
- Most likely to practice safe sex were Canadian and German backpackers, with up to 80% consistently using condoms.
- Backpackers were more likely to have sex with travellers from other countries, while males are also likely to use local sex workers.

STIs – who’s at highest risk?

In 2013, a 14-year study of STI patterns and rates among 112,180 international travellers found that the type of infections varied among different classes of travellers.
Those most likely to be diagnosed with an STI were:
- Male travellers
- Younger adults
- Businesspeople
- VFRs (Visiting Friends and Relatives abroad)
- Short-stay travellers (less than 30 days)
- Immigrants
- Travellers who had not sought pre-travel medical advice
The most common travel-related STIs where non-gonococcal or other unspecified urethritis, acute HIV infection, and syphilis. For men, urethritis and epididymitis were most common, while cervicitis topped the list of STIs for women. 

Condoms have some limitations

Condoms are as important as sunscreen, personal insect repellent, and sanitising hand gel.
While condoms are widely available overseas, their quality can vary. Our advice is:
- Take your own from Australia: You can be sure of their quality.
- If you purchase them overseas, first check the expiry date and make sure the pack carries a recognised quality assurance mark.
- Use only water-based lubricants with latex condoms.
It’s important to remember that condoms have limitations.
Condoms WILL protect against: HIV, Hepatitis B and C, gonorrhoea, chlamydia, and syphilis.
Condoms WILL NOT prevent: Genital herpes, genital warts, pubic lice, or scabies.
Read more about male and female condoms and how to use them correctly. 

Safe sex is smart – at any age

Enjoying sun, sea and sex on holiday is not just for 20-somethings: a separate British study published in the journal, Sexually Transmitted Infections found that older holiday-makers – one-in-20 men and one-in-40 women aged 35 to 74 – had a sexual relationship with a new partner while travelling abroad.
Researchers found that those travellers who found a new sexual partners abroad were also more likely to engage in risky behaviour, such as unprotected sex. They concluded: “These proportions are likely to increase as older people maintain good health, have the financial means to travel, and are now more likely to experience partnership breakdown.”
Regardless of age, if you’ve had unprotected sex while abroad, have a sexual health check-up – including a screening for STIs – through your GP, a sexual health clinic, or a Travelvax Australia clinic as soon as possible after you return.
A thorough check-up provides reassurance and ensures there is no delay in treatment if you returned home with an STI. Just as importantly, by getting diagnosed and treated early you could help prevent the spread of antibiotic resistant infections in your community.

 

Image: Dreamstime

By Dr Eddy Bajrovic*

As the mercury dips each autumn, winter viruses loom large on the horizon.
Not just the more familiar seasonal influenza and colds (rhinoviruses): Winter is also the peak season for norovirus, the most common cause of gastroenteritis worldwide.
Noroviruses thrive in nursing homes, hospitals, large offices, universities, schools… in fact, in any confined, crowded space. Which is why norovirus outbreaks are not uncommon on cruise ships and at holiday resorts.
What make norovirus so contagious that it causes more than 90% of the world’s non-bacterial outbreaks of gastroenteritis? There are a couple of reasons.
Firstly, a single infected person can shed literally billions of norovirus particles. It takes as few as 18 particles to infect another person and they can be infected in a number of ways.
Secondly, just like influenza, noroviruses are constantly mutating. And, like flu, past infection offers no immunity to the new strains that emerge every couple of years.
The global economic burden of norovirus is a staggering $60 billion per year, with an annual estimated death toll of 200,000, according to new estimates drawn from studies of the disease and its impact. 

Read more ...

By Dr Eddy Bajrovic*

Our Games athletes and officials have been advised to pack a mosquito-proof bed net when they travel to Brazil for the 2016 Olympics in August.
Australian organisers want to ensure our team members avoid mosquito-borne viruses such as Zika, dengue, chikungunya, and yellow fever. Malaria is also present in areas of the northern Amazon states.
But, it’s Zika that is creating global headlines. The WHO yesterday declared Zika a Public Health Emergency of International Concern and has urged a coordinated international response. 
There have been an estimated 1.5 million cases in Brazil in the past 10 months and the virus is now spreading rapidly throughout neighbouring countries of the Americas and the Caribbean. At least 26 nations have reported Zika to date, while dengue and chikungunya are well entrenched in every country in the region.
What’s added a tragic twist to the Zika tale is the strong suspicion that the virus is behind hundreds of cases of microcephaly in infants born to mothers infected during pregnancy, as well as (much rarer) cases of the auto immune disease, Guillain-Barré syndrome. Scientists also believe it can be passed on in semen, breast milk and through blood transfusions.
Despite this, for 80% of people who get the virus the symptoms are either mild or completely absent. But, even without the rash, red eyes, low-grade fever and joint pain lasting up to a week, anyone with the virus in their bloodstream can pass it on if an Aedes mosquito bites them and then bites someone else. 

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By Dr Eddy Bajrovic*

Dr Cameron Webb is the man the Travelvax Report turns to for his expert knowledge of insects – especially the ones that bite.
There’s not much the Sydney-based entomologist doesn’t know about mozzies, including the two disease-carrying Aedes species that are spreading to every corner of the world’s tropical regions.
After reading last week’s article advising Year 12 students about to head overseas for schoolies or a gap year, Dr Webb had some keen observations to share.
Indeed, they’re relevant for travellers of all ages.
Besides the vaccinations we recommended for travel to developing countries, he says there are a couple of other major differences between overseas schoolies (and holiday) destinations like Bali or Fiji and local ones like Queensland’s Gold Coast that Australians often don’t appreciate.
Among them, the consistent risk of the mosquito-borne viruses, dengue and chikungunya and the very ‘un-Australian’ biting patterns of the aggressive mozzies that spread them - Aedes aegypti (also known as the ‘Yellow Fever mosquito’) and Aedes albopictus (the ‘Asian Tiger’).

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