Tetanus is caused by a toxin released from Clostridium tetani bacteria and occurs worldwide. Tetanus bacteria are present in soil and manure and may be introduced through open wounds such as a puncture wound, burn or scratch.

Prevention

Travellers should thoroughly clean all wounds and seek medical attention for injuries such as animal bites/scratches, burns or wounds contaminated with soil.

Tetanus vaccination

• Travellers should have completed a tetanus vaccination course according to the UK schedule.
• If travelling to a country or area where medical facilities may be limited, a booster dose of a tetanus-containing vaccine is recommended if the last dose was more than ten years ago even if five doses of vaccine have been given previously.

Country-specific information on medical facilities may be found in the 'health' section of the FCDO foreign travel advice pages.

Tetanus in brief

Rabies is a viral infection which is usually transmitted following contact with the saliva of an infected animal most often via a bite, scratch or lick to an open wound or mucous membrane (such as on the eye, nose or mouth). Although many different animals can transmit the virus, most cases follow a bite or scratch from an infected dog. In some parts of the world, bats are an important source of infection.

Rabies symptoms can take some time to develop, but when they do, the condition is almost always fatal.

The risk of exposure is increased by certain activities and length of stay (see below). Children are at increased risk as they are less likely to avoid contact with animals and to report a bite, scratch or lick.

Rabies in USA

Most travellers to this country are considered to be at low risk for rabies. However some animals may pose a greater risk of rabies for travellers, e.g. skunks, racoons and foxes. Bats may carry rabies-like viruses in this country.

Prevention

• Travellers should avoid contact with wild animals including bats. Rabies is preventable with prompt post-exposure management.
• Following a possible exposure, wounds should be thoroughly cleansed and an urgent local medical assessment sought, even if the wound appears trivial. Although rabies has not been reported in domestic animals, it is still sensible to seek prompt medical advice if bitten or scratched by all animals.
• Post-exposure management following contact with wild animals, including bats, should be in accordance with national guidelines.

Rabies vaccination

• Pre-exposure vaccines could be considered for those who are at increased risk of exposure to wild animals especially foxes and bats.

Rabies in brief

There is a risk of altitude illness when travelling to destinations of 2,500 metres (8,200 feet) or higher. Important risk factors are the altitude gained, rate of ascent and sleeping altitude. Rapid ascent without a period of acclimatisation puts a traveller at higher risk.

There are three syndromes; acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). HACE and HAPE require immediate descent and medical treatment.

Altitude illness in USA

There is a point of elevation in this country higher than 2,500 metres. Example places of interest: Mt McKinley 6,194m, Mt Rainier 4,392m, Pikes Peak 4,301m, Leadville 3,100m and Mt Kea (Hawaii) 4,205m.

Prevention

• Travellers should spend a few days at an altitude below 3,000m.
• Where possible travellers should avoid travel from altitudes less than 1,200m to altitudes greater than 3,500m in a single day.
• Ascent above 3,000m should be gradual. Travellers should avoid increasing sleeping elevation by more than 500m per day and ensure a rest day (at the same altitude) every three or four days.
• Acetazolamide can be used to assist with acclimatisation, but should not replace gradual ascent.
• Travellers who develop symptoms of AMS (headache, fatigue, loss of appetite, nausea and sleep disturbance) should avoid further ascent. In the absence of improvement or with progression of symptoms the first response should be to descend.
• Development of HACE or HAPE symptoms requires immediate descent and emergency medical treatment.

Altitude illness in brief

Insect or tick bites can cause irritation and infections of the skin at the site of a bite. They can also spread certain diseases.

Diseases in North America

There is a risk of insect or tick-borne diseases in some areas of North America. This includes diseases such as West Nile virus.

Prevention

• All travellers should avoid insect and tick bites day and night.
• There are no vaccinations (or medications) to prevent these diseases.

Further information about specific insect or tick-borne diseases for this country can be found, if appropriate on this page, in other sections of the country information pages and the insect and tick bite avoidance factsheet.

Dengue is a viral infection spread by mosquitoes which mainly feed during daytime hours. It causes a flu-like illness, which can occasionally develop into a more serious life-threatening illness. Severe dengue is rare in travellers.

The mosquitoes that spread dengue are more common in towns, cities and surrounding areas.

Dengue outbreaks are reported from time to time in United States. Affected states include California, Florida, Hawaii, and Texas.

Dengue in USA

Prevention

• Travellers should avoid mosquito bites particularly during daytime hours.
• A dengue vaccine is licensed in the UK for the prevention of dengue disease in individuals from 4 years of age. The Joint Committee on Vaccination and Immunisation (JCVI) and World Health Organization are in the process of reviewing the product information. Recommendations on the use of this vaccine will be published in due course.

Dengue in brief

Seasonal influenza is a viral infection of the respiratory tract and spreads easily from person to person via respiratory droplets when coughing and sneezing. Symptoms appear rapidly and include fever, muscle aches, headache, malaise (feeling unwell), cough, sore throat and a runny nose. In healthy individuals, symptoms improve without treatment within two to seven days. Severe illness is more common in those aged 65 years or over, those under 2 years of age, or those who have underlying medical conditions that increase their risk for complications of influenza.

Seasonal influenza in USA

Seasonal influenza occurs throughout the world. In the northern hemisphere (including the UK), most influenza occurs from as early as October through to March. In the southern hemisphere, influenza mostly occurs between April and September. In the tropics, influenza can occur throughout the year.

Prevention

All travellers should:

• Avoid close contact with symptomatic individuals
• Avoid crowded conditions where possible
• Wash their hands frequently
• Practise ‘cough hygiene’: sneezing or coughing into a tissue and promptly discarding it safely, and washing their hands
• Avoid travel if unwell with influenza-like symptoms
• A vaccine is available in certain circumstances (see below)*

*In the UK, seasonal influenza vaccine is offered routinely each year to those at higher risk of developing of severe disease following influenza infection, and certain additional groups such as healthcare workers and children as part of the UK national schedule (see information on vaccination). For those who do not fall into these groups, vaccination may be available privately.

If individuals at higher risk of severe disease following influenza infection are travelling to a country when influenza is likely to be circulating they should ensure they received a flu vaccination in the previous 12 months.

The vaccine used in the UK protects against the strains predicted to occur during the winter months of the northern hemisphere. It is not possible to obtain vaccine for the southern hemisphere in the UK, but the vaccine used during the UK influenza season should still provide important protection against strains likely to occur during the southern hemisphere influenza season, and in the tropics.

Avian influenza

Avian influenza viruses can rarely infect and cause disease in humans. Such cases are usually associated with close exposure to infected bird or animal populations. Where appropriate, information on these will be available in the outbreaks and news sections of the relevant country pages. Seasonal influenza vaccines will not provide protection against avian influenza.

Avian influenza in brief

Poor air quality is a significant public health problem in many parts of the world. Exposure to high levels of air pollution over short time periods (e.g. minutes/hours/days) and longer time periods (e.g. years) is linked to many different acute and chronic health problems. These effects are mainly on the respiratory (lungs and airways) and cardiovascular (heart function and blood circulation) systems.

Current information on world air quality is available from the world air quality index project.

Prevention

Travellers with health problems that might make them more vulnerable to the effects of air pollution who are travelling to areas of high pollution should:

• discuss their travel plans with their doctor, and carry adequate supplies of their regular medication.
• take sensible precautions to minimise their exposure to high levels of air pollution.
• check local air quality data and amend their activities accordingly.
• take notice of any health advisories published by the local Ministry of Health and Department for Environment, and follow the guidance provided.

It is unclear if face masks are beneficial at reducing exposure and may make breathing more difficult for those with pre-existing lung conditions. Those who choose to use one should make sure that the mask fits well and know how to wear it properly.

Outdoor air quality in brief

Zika virus (ZIKV) is a viral infection spread by mosquitoes which predominantly feed during daytime hours. A small number of cases of sexual transmission of ZIKV have also been reported. Most people infected with ZIKV have no symptoms. When symptoms do occur, they are usually mild and short-lived. Serious complications and deaths are not common. However, ZIKV is a cause of Congenital Zika Syndrome (microcephaly and other congenital anomalies) and neurological complications such as Guillain-Barré syndrome.

Cases have previously been reported in Florida, as well as in Hidalgo and Cameron Counties in Texas.

Zika virus in USA

Based on current evidence there is a negligible risk of Zika virus.

Prevention

• All travellers should avoid mosquito bites particularly during daytime hours.
• There is no vaccination or medication to prevent Zika virus infection.

Zika virus in brief