Here’s an update on how to advise patients travelling to Brazil for the Rio Olympic games
South America, particularly Brazil, is always high on the list of Australian travellers, and with the 2016 Rio Olympic Games fast approaching, the numbers will only grow, writes Sarah Chu and Michael Cheung
As well as Rio De Janeiro, the Games will take place in the co-host cities of Belo Horizonte, Brasilia, Manaus, Salvador and São Paolo.
Here’s an update on how to advise patients travelling to the region.
Yellow fever
It is vital to alert travellers that the World Health Organisation (WHO) lists parts of Brazil as endemic for yellow fever – spread by the Aedes and Haemagogus mosquito. The risk of yellow fever virus transmission in Brazil means that responsibility is placed on healthcare professionals to advise travellers on the necessary requirements.
It is recommended that travellers over the age of nine months be vaccinated for yellow fever no less than 10 days before going to Brazil.
Travellers will be required to provide an international vaccination certificate upon arriving or returning to Australia. The Australian government has adopted the WHO amendment to Annex 7 of the International Health Regulations (2005), meaning the term of validity of the yellow fever vaccination certificate has changed from 10 years, to the lifetime span of the person vaccinated.
As of June 2016, travellers with a certificate older than 10 years will now be accepted into Australia. This has followed research showing that for the majority of people, a single dose of yellow fever vaccine results in life-long immunity.
If you don’t offer yellow fever vaccination, the Department of Health provides a list of Australian clinics.
It is important to seek travellers’ full itineraries; some countries may refuse entry without a valid yellow fever vaccination certificate.
Zika virus
Brazil, along with other South American countries, is experiencing outbreaks of the Zika virus – mostly spread by the bite of an infected Aedes mosquito. Zika virus can also be sexually transmitted from an infected man to his sexual partners. At present there is no vaccine against Zika virus, rendering mosquito-bite prevention all the more necessary.
It is important to remember that 80% of Zika infections are asymptomatic.
All pregnant women, regardless of trimester, should be advised to postpone travel to Brazil because of the risk of birth defects, in particular microcephaly. If this is not possible, then strict adherence to insect bite prevention is recommended.
Pregnant women whose male partners have lived in or travelled to Brazil during the current outbreak are advised to use condoms or abstain from vaginal, anal and oral sex during the term of their pregancy.
Currently, we have insufficient knowledge about the persistence and infectivity of Zika in semen, but it is recommended that men with confirmed infection should abstain from sexual activity, or use condoms for three months following the resolution of their symptoms.
For couples planning a pregnancy, this should be delayed if there has been known exposure to the Zika virus.
In the case of possible exposure, men could be offered pre-conception serological testing at least four weeks after the most recent potential exposure, however it must be borne in mind that cross-reactivity can occur with other arboviruses.
The CDC provides further pre-conception information. The Department of Health details current Australian recommendations for assessing pregnant women returning from Zika virus endemic areas.[4]
This situation is evolving rapidly as new information comes to light. For example, in the last fortnight, some evidence has suggested that infection in the third trimester may not result in birth defects. To access the latest advice, check the CDC and WHO websites regularly, as well as the Australian Department of Health for local guidelines.
Malaria
Brazil is also a known high-risk area for malaria, however Rio De Janeiro is malaria-free. Plasmodium vivax is the main species of malarial parasite in the Amazon basin, including areas around the co-host city Manaus, although approximately 15% of malarial cases in this region are caused by P. falciparum.
Whether to advise travellers to Manaus and the Amazon Basin to use malarial chemoprophylaxis, or take stand-by treatment, depends on the type of traveller.
Common chemoprophylaxis choices for this region may range from doxycycline, mefloquine or atovaquone-proguanil. Chloroquine resistance occurs in this region and would not be recommended.
Some travellers tend to forget or forgo strict insect prevention because they believe prophylaxis alone will protect them. Remind patients that the aim of chemoprophylaxis is to prevent death and severe disease, not prevent all malaria infections. Thus precautionary measures remain essential, even while taking medication, for the prevention of malaria and other arboviruses.
Other arboviruses
Brazil is also a hot spot for dengue fever and chikungunya. In particular, Brazil is the country with the highest number of dengue cases worldwide.
Although Rio is malaria-free, dengue and chikungunya can be transmitted by the Aedes and sometimes albopictus mosquitoes. Travellers to Rio should be instructed to practice daytime bite prevention measures to protect against these urban daytime biters.
Currently there are no vaccines for dengue in Australia or antiviral treatment available for these infections.
Therefore, mosquito bite prevention is absolutely crucial, particularly in built-up, urban areas. Both species of mosquito bite outdoors, but Aedes aegypti can also be found feeding indoors.
The virus that causes dengue is divided into four closely related serotypes and those serotypes can be further divided into genetic variants, or subtypes. Multiple strains of dengue are found circulating in Brazil.
Recovery from infection by one strain provides lifelong immunity against that particular serotype. However, cross-immunity to the other serotypes after recovery is only partial and temporary.
Hence, a person’s prior immune response to one serotype of dengue virus can influence the interaction with virus subtypes in a subsequent infection. Instead of boosting immunity, each new infection with a new serotype may increase the risk of developing severe dengue, also known as Dengue Haemorrhagic Fever.
It is also important to note that dengue and Zika virus often present with similar symptoms.
Respiratory infections
While Brazil’s peak flu season is in June and July, there is still a risk of contracting the illness outside this period, especially in the context of mass gatherings such as the Olympics. Influenza is among the most common vaccine-preventable disease in travellers.
At-risk groups, including the elderly, pregnant women, the very young, Aboriginal and Torres Strait Islander people and some with compromised immune systems, should receive influenza vaccination at least two weeks before departure if not already vaccinated.
Food and waterborne diseases
Many travellers aren’t always conscientious about the risks of foodborne illness, and can forget or overlook safe eating and drinking habits.
Hepatitis A and typhoid are both contracted by ingesting food and water contaminated by the faeces of infected people, particularly in areas of lower sanitation and hygiene. Typhoid is seen in high incidences in the North and North-East of Brazil (including the Amazonas), while hepatitis A is of intermediate endemicity.
Pre-travel vaccination is recommended for these diseases.
Many travellers visiting friends and relatives assume they are immune to infectious diseases, however, particularly for people who left their country of origin years before, immunity may have waned and no longer offer protection. Fewer than 30% of this group seek travel health advice, though they stay on average double the duration of other travellers, and experience a higher incidence of travel-related infections.
Travellers should also be wary of non-infectious hazards during mass gatherings, including accidents, injuries, crime, sunburn and excess alcohol intake. Travel continues to be a risk factor for STIs. Safer sex, including consistent and reliable condom use, should be encouraged. Doctors may also consider discussing pre-exposure prophylaxis with men who have sex with men, who are at higher risk for acquiring HIV infection.
Other health concerns
- Jet lag
- Deep vein thrombosis
- Altitude sickness
- Motion sickness
- Although influenza is a common respiratory illness, travellers should be advised against disturbing soil in order to minimise the risk of inhaling fungal spores.
- Leptospirosis risks can be increased in those participating in recreational water activities, particularly after heavy rainfall or flooding
- Chagas disease has been eliminated in most Brazilian states through insecticide spraying, however occasional outbreaks from contaminated food or drink have been reported including locally prepared juice containing açái.
- Schistosomiasis is found in freshwater lakes and rivers, not saltwater
- Both cutaneous and visceral leishmaniasis occur in Brazil and are most common in the Amazon and Northeast regions
- Walking barefoot on sandy beaches or moist soft soil that has been contaminated with animal faeces, including dogs, is a risk factor for cutaneous larva migrans. This can cause an itchy serpiginous track from direct larval invasion of the skin. Travellers can protect themselves by wearing footwear and using a beach mat or towel when sunbathing to avoid direct skin contact with contaminated ground.
- Several tick borne rickettsial diseases have been identified in Brazil, so travellers should avoid flea and tick bites.
The pre-travel consult provides a good opportunity to ensure routine immunisations are up-to-date, including: polio, diphtheria, pertussis, measles, mumps, rubella, varicella, and pneumonia, or if patients are overdue for booster vaccinations such as tetanus. Other vaccinations such as Hepatitis B, rabies, cholera may also be discussed.
Checklist
Where have you travelled in the past?
- Have you spent a long time (More than six months) in high-risk countries?
- Have you fallen ill with any diseases while travelling?
- What travel vaccinations have you received in the past?
- What routine vaccinations have you received as a child?
- Have you had any booster vaccinations?
Further resources can be found at the WHO, the Center for Disease Control (CDC), the Austrralian Department of Health and the CDC Yellow Book, which is available for free online. The CDC also has two helpful, free apps called: Can I eat this? and TraveWell.
Dr Sarah Chu is a travel health specialist and Michael Cheung is a pharmacist
