This type of infectious illness are second only to diarrhoea as a cause of illness in travellers. Certain situations encountered when travelling place travellers at an increased risk of acquiring a respiratory infection.

Catching a cold at home is easy enough but travelling will increase your susceptibility and expose you to new germs to which you have no natural immunity.

Coughs, colds and sore throats are very common in travellers but can be easily treated using over the counter remedies which are available in pharmacies and drug stores world-wide. Antibiotics can be purchased over the counter in many countries but should be avoided in this instance since they are totally ineffective against cold viruses.

The majority of respiratory tract infections are viral and are therefore not susceptible to antibiotic treatment. When prescribed, antibiotics are often for secondary infections.

Many travellers spend long periods of time in crowded conditions such as airports, hotels etc. These places provide ideal conditions for spreading many acute respiratory infections like common colds and influenza.

Dry aircraft cabin atmospheres and smoking more than usual (even passively), exposure to new allergens, dust and city air pollution will all contribute to respiratory symptoms.

Meningococcal infections, although not themselves infections of the respiratory tract are also spread through the respiratory route and there have been outbreaks in tourist resorts. Vaccination should be considered for those at risk in endemic areas during outbreaks.

These infections are difficult to prevent because of the ease with which they are spread from person to person. Those liable to chest infections may benefit from taking an 'emergency' course of antibiotics with them.

Influenza

Influenza, also known as the flu, is a very contagious disease that is caused by the influenza virus. It attacks the respiratory tract in humans and is different from a cold. Influenza usually comes on suddenly and may include the following symptoms:-

These are known as the classic "flu-like" symptoms and are not unlike the symptoms of other illnesses such as malaria. Indeed many people have mistaken the onset of malaria for a bout of flu and have not taken appropriate action with sometimes serious consequences.

Flu is most common during the winter season, which in the southern hemisphere is summer in the northern hemisphere and visa-versa. It can occur year round in the tropics. Although Influenza is a familiar illness, and is often fairly mild in many healthy adults it is however, a serious and sometimes fatal illness among frail and elderly persons. Vaccination should be considered for those at risk.

Influenza viruses are spread is from person to person by "droplet spread". This happens when droplets from a cough or sneeze of an infected person are propelled through the air. The viruse also can be spread when a person touches respiratory droplets on another person (e.g. by shaking hands) and that person then touches their own mouth or nose (or someone else’s mouth or nose) before washing their hands.

A person can start spreading the flu virus one day before he or she feels sick and can continue to pass the flu virus to others for another three to seven days after the symptoms start. Symptoms start one to four days after the virus enters the body. Some persons can be infected with the flu virus but have no symptoms but they can still spread the virus to others. The disease can spread more easily amongst large groups of people living in relatively close proximity to each other e.g. cruise ships.

Treatment: Influenza is caused by a virus, so antibiotics don't work to cure it. The best way to prevent the flu is to get an influenza vaccine each autumn, before the flu season. If you do happen to get it, then the following treatment should be undertaken:-

• Rest
• Drink plenty of fluids
  
• Avoid drinking alcohol and smoking tobacco
  
• Take medication to relieve the symptoms

Diphtheria

Respiratory diphtheria is a bacterial infection that causes a moderately sore throat with a greyish membrane over the infected area (usually membranes of the tonsils, pharynx, or nose) with low grade fever. In severe cases the neck tissue may become very swollen.

It is passed from person to person by droplet transmission, usually by breathing in diphtheria bacteria after an infected person has coughed, sneezed or even laughed. It can also be spread by handling used tissues or by drinking from a glass used by an infected person.

In tropical countries the infection may occur as skin ulcers and is known as cutaneous diphtheria which presents as infected skin lesions which lack a characteristic appearance.

After two to six weeks, the effects of toxins produced by the bacteria become apparent with severe muscle weakness, mainly affecting the muscles of the head and neck. Inflammation of the heart muscle may cause heart failure. Myocarditis, polyneuritis, and airway obstruction are common complications of respiratory diphtheria; death occurs in 5%-10% of respiratory cases.

Transmission is usually by direct person to person contact. Avoid very close contact with infected people particularly kissing and sharing bottles or glasses. It spreads quickly amongst infected people in crowded places. Cutaneous lesions are also important in transmission.

Diphtheria remains endemic in developing countries and the countries of the former Soviet Union have reported an epidemic which began in 1990.

Treatment: is specialised and requires medical supervision in hospital where Diphtheria antitoxin is given as an intramuscular or intravenous injection as soon as possible. The infection is then treated with antibiotics, such as penicillin or erythromycin.

Prevention: There is a vaccine for diphtheria. Most people in the UK receive their first dose as a child in the form of a combined vaccine called DTP (diphtheria-tetanus-pertussis).
Immunisation: is very effective but protective immunity is not present longer than 10 years after the last vaccination, so it is important for adults at risk to get a booster of tetanus-diptheria (Td) vaccine every 10 years.

Legionnaires Disease

Legionnaires' disease, a form of pneumonia is a severe infection which is caused by the bacterium Legionella Pneumophila. It has been linked to contaminated water used in water cooled air-conditioning systems and sometimes showers. It is believed to occur worldwide.

Legionella organisms can be found in many types of water systems. However, the bacteria reproduce to high numbers in warm, stagnant water such as that found in certain plumbing systems and hot water tanks, cooling towers and evaporative condensers of large air-conditioning systems, and whirlpool spas.

Outbreaks of legionellosis have occurred after persons have breathed mists that come from a water source (e.g., air conditioning cooling towers, whirlpool spas, showers) contaminated with Legionella bacteria. Persons may be exposed to these mists in hotels, hospitals, or public places.

Legionaires' is not passed from person to person, and there is no evidence of persons becoming infected from auto air conditioners or household window air-conditioning units.


People of any age may get Legionnaires' disease, but the illness most often affects middle-aged and older persons, particularly those who smoke cigarettes or have chronic lung disease. The time between the patient's exposure to the bacterium and the onset of illness for Legionnaires' disease is 2 to 10 days. There is a significant mortality rate particularly among the elderly.

Patients with Legionnaires' disease usually have fever, chills, and a cough, which may be dry or may produce sputum. Some patients also have muscle aches, headache, tiredness, loss of appetite, and, occasionally, diarrhoea.

Erythromycin is the antibiotic currently recommended for treating persons with Legionnaires' disease. In severe cases, a second drug, rifampicin, may be used in addition. Other drugs are available for patients unable to tolerate erythromycin.

Tuberculosis

Pulmonary tuberculosis is a contagious bacterial infection caused by Mycobacterium tuberculosis (TB). The lungs are primarily involved causing persistent cough with fever and sweating, but the infection can spread to other organs. The disease is slow to establish itself and general malaise, weakness and weight loss are characteristic during this incubation which may be up to twelve weeks. The disease is characterised by the development of granulomas (granular tumours) in the infected tissues.

TB is much more common in some parts of the world than in the UK. The risk to travellers is limited since transmission of the disease usually requires prolonged close contact. Sometimes the disease can be overwhelming; producing meningitis and coma; this particularly dangerous form is usually found in children and those who have not previously been vaccinated or exposed to the disease. Recently, antibiotic-resistant strains of tuberculosis have appeared.

Tuberculosis can develop after inhaling droplets sprayed into the air from a cough or sneeze from an infected person and it can also spread through infected sputum and there is a form spread through milk from infected cows. The risk of contracting TB increases with the frequency of contact with people who have the disease, and with crowded or unsanitary living conditions and poor nutrition.

Pulmonary TB develops in the minority of people whose immune systems do not successfully contain the primary infection. The disease may occur within weeks after the primary infection, or it may lie dormant for years before causing disease. The extent of the disease can vary from minimal to massive involvement, but without effective therapy, the disease becomes progressive.

Infants, the elderly, and individuals who are immunocompromised, those undergoing transplant surgery who are taking anti rejection medications are at higher risk for progression of the disease or reactivation of dormant disease. Those who have not received BCG immunisation are advised to do so and if for travel purposes, at least six weeks before departure to ensure a protective level of immunity.

Treatment with anti microbial drugs is effective but is prolonged and requires medical supervision. It is also expensive and not always available abroad. Incomplete treatment of TB infections (such as failure to take medications for the prescribed length of time) can contribute to the emergence of drug-resistant strains of bacteria.

Prevention: Avoid overcrowded places in endemic areas, particularly where spitting is common. Never drink unpasteurised milk. If in doubt, boil it before drinking. There is a vaccination (BCG) which can give a valuable degree of protection, particularly in children. Travellers who plan to spend more than a month in an area with a high tuberculosis rate and who have not been previously immunised should consider immunisation with BCG.

SARS
(Severe Acute Respiratory Syndrome)
is a severe pneumonia that has been reported in China Hong Kong, Vietnam, Singapore, Taiwan, Indonesia, the Philippines, Thailand and Canada. It appears to have spread in a short period of time and is now regarded by the World Health Organisation as a worldwide threat.

Travellers to areas where SARS has been reported should be aware of the symptoms and seek immediate medical advice should they develop any symptoms within ten days of returning from an infected region.

Since April 2nd (2003) the Department of Health has strongly advised against travel to Hong Kong and Guangdong Province in southern China where the disease appears to have its origins. More recently they have added Beijing and Shanxi Province in China and Toronto in Canada. Travellers are also advised to ensure that they have adequate insurance to cover medical care and unplanned extensions to their stay.

Cases in the UK are most likely to occur in people returning from an affected area, especially one where transmission is thought to be continuing such as Hong Kong or Guangdong Province. Recent data suggests that transmission has slowed or stopped in certain areas i.e. Canada, Singapore, Vietnam and Taiwan but caution is still advised.

The infection is thought to be passed on by close contact with an infected person, aerosol infection if it occurs is rare. The initial signs are a flu like illness developing within ten days of contact. Symptoms include rapid onset of high fever followed by headache, muscle aches and respiratory symptoms including cough, sore throat, shortness of breath and difficulty breathing. There have been numerous fatalities.

The organism responsible for SARS was originally thought to be a paramyxo virus similar to the viruses responsible for causing measles and mumps but It has now been identified as a member of the coronavirus family never previously seen in humans. Identification of the coronavirus means that scientists can now move towards developing treatments for SARS and successfully controlling the disease. At present there is no specific treatment.

Outbreaks such as the one in Toronto which affected family members and health care workers are thought to have occurred early in the epidemic when the significance of the condition was not appreciated. Where infection control measures are applied, outbreaks seem not to occur. Therefore, anyone thought to be suffering from the illness should be isolated and nursed using barrier techniques. Secondary infections can be controlled with antibiotics and symptomatic treatment undertaken.

Avian Influenza (Bird Flu)

Type A influenza viruses can infect several animal species, including birds, pigs & horses. Birds are an especially important species because all known subtypes of the virus circulate among wild birds, which are considered the natural hosts for influenza A viruses and when they infect birds they are known as "avian influenza viruses." Avian influenza viruses do not usually directly infect humans or circulate among humans.

Avian influenza usually does not make wild birds sick, but can make domesticated birds very sick and kill them. They do not usually infect humans; however, several instances of human infections and outbreaks have been reported since 1997. When such infections occur, public health authorities monitor the situation closely because of concerns about the potential for more widespread infection in the human population.

The reported symptoms of avian influenza in humans have ranged from typical influenza-like symptoms (e.g., fever, cough, sore throat and muscle aches) to eye infections, pneumonia, acute respiratory distress, viral pneumonia, and other severe and life-threatening complications.

Currently there is no definitive evidence of human-to-human transmission of avian influenza and no infections have been documented among health-care workers. While it is unusual for people to get influenza infections directly from animals, such transmission has been documented several times in recent years and is under investigation although most human cases have been linked to direct contact with diseased birds.

The World Health Organisation and other health authorities worldwide are seriously concerned over the co-circulation of human and highly pathogenic animal influenza viruses since an exchange of genes between the two viruses might occur if individuals were co-infected with both viruses which could give rise to a new virus to which humans would have little or no immunity and which could be transmitted from person to person.

It is recommended that travellers to countries experiencing outbreaks of avian influenza in poultry should avoid areas with live poultry, such as live animal markets and poultry farms. Large amounts of the virus are known to be excreted in the droppings from infected birds. Be sure to include a thermometer and alcohol-based hand sanitiser for hand hygiene in your travel health kit.