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Which diseases are infectious?
There are a very great number of infectious diseases due to infection with bacteria and viruses and the following are just some of the more common ones found worldwide.
Malaria
Malaria is a public health problem in some 90 countries, and causes between 1.5 and 2.7 million deaths world-wide each year.
AIDS
AIDS, or Acquired Immune Deficiency Syndrome, is linked to HIV virus, which can be passed from human to human through blood to blood contact.
Tuberculosis
Tuberculosis is usually thought of as a lung disease but can affect almost every organ in the body. It kills many people world-wide, particularly children and is increasingly common in the UK, with many of the 11 cases per 100,000 population of coming from people recently returned from trips abroad or in people settling in the UK from areas where TB is endemic.
Measles
Measles was prevalent among children in the UK until recent years - the last mini-epidemic was in the late 1980s. But the disease, characterised by the red skin rash and high temperatures, can cause permanent disability or even kill. Worryingly, since the MMR vaccination scare, lower levels of vaccination in the UK have caused several outbreaks of measles in susceptible groups of children, and sadly, deaths of affected children.
Diarrhoeal Diseases
Poor hygiene and water supplies are the main factors behind the spread of diseases like dysentery and cholera.
Acute respiratory infections
These can range from simple coughs and colds to various types of pneumonia.
Top
Causes and risk factors
Malaria
Malaria is caused by a parasite, Plasmodium, of which there are several varieties, which is passed on from infected humans when they are bitten by mosquitoes, which then go on to bite non-infected people. Malaria is a public health problem in some 90 countries, and causes between 1.5 and 2.7 million deaths world-wide each year.
In developing countries, where poorer nutrition and living conditions have reduced children's natural immune response to the parasite infection, it is fatal far more often.
AIDS
AIDS is commonly spread by unprotected sexual intercourse, both homosexual and heterosexual, and is a major killer in developing countries, where there is a higher degree of infection in the heterosexual community, and less use of protection such as condoms. In these countries, immune resistance is generally lower due to poorer nutrition and general health, and consequently, the development of full-blown AIDS, and death from opportunistic infections is far swifter.
Tuberculosis
Tuberculosis is caused by bacterial infection, mycobacterium tuberculosis. It is often linked to AIDS and HIV illness, as it is common in patients with reduced immunity.
Measles
Measles is due to a virus and is spread by droplet infection. Children in some areas of the world, such as parts of Africa, are much more susceptible to infection than in the developed world.
Diarrhoeal Diseases
Poor hygiene and water supplies are the main factors behind the spread of diseases like dysentery and cholera. Both, although quite treatable, cause death through dehydration, as the body cannot replace the water and body salts it loses through diarrhoea attacks. All are far more prevalent in developing countries, which may have no efficient sewage disposal system, leading to the contamination of water supplies.
More recently, the breakdown of proper water treatment facilities in eastern European countries such as Latvia has led to outbreaks of diseases like cholera. In the UK, the past decade has seen a vast increase in the number of food poisoning cases reported to the authorities. Again, these are rarely fatal, although the potent 0157 strain of the E.coli bacterium killed many elderly or sick patients during a recent Scottish outbreak.
Acute respiratory infections
Pneumonia is caused by viruses, bacteria and parasites. Many respiratory tract infections are very infectious, particularly in the early stages, and can be spread through droplets from sneezes or coughs, or from dirty tissues or water glasses.
Top
Symptoms
Malaria
The symptoms are bouts of fever, tiredness, headache, nausea, and muscular pain, leading, without treatment, to delirium, convulsions and death.
AIDS
Although HIV is symptomless, over time, it reduces the body's ability to deal with outside infections. When the body's immune system has been rendered ineffective, it is highly vulnerable to other predatory infections, such as TB, which may have already been lying dormant.
Tuberculosis
The most common symptoms are a persistent cough, which may involve coughing up blood, fevers, night-sweats, weight loss and tiredness. Once contracted, it can lie dormant in the lung, only developing into the disease if the body's immune system weakess.
Acute respiratory infections
Pneumonia is a term used to refer to a variety of lung infections caused by viruses, bacteria and parasites. Common symptoms include fever, a cough, rapid breathing, chest pain, and perhaps a bluish or grey colour of the lips or fingertips, indicating that the body is not getting enough oxygen through the lungs.
Top
Treatment and prevention
Malaria
If treated promptly, it is a curable disease, and travellers are advised to take a course of anti-malaria drugs to protect them before going abroad. However, nothing can provide 100% protection against malarial infection.
AIDS
Although once full-blown AIDS has developed, it becomes increasingly difficult to treat these infections. The HIV-positive stage can be lengthened by many years using modern anti-viral treatments.
Tuberculosis
Treatment is by a six-month course of antibiotics, and provided this is followed, the cure rate is high. However, symptoms generally disappear long before the end of the treatment course, and the failure of many people to continue for the full six months has been blamed for the emergence of TB strains resistant to antibiotics. The BCG vaccine is no longer given routinely to school age children in the UK due to the drastically reduced infection rate but is given selectively to babies and other children considered at risk of infection.
Measles
In this country, the MMR (Measles, mumps and rubella) vaccination is given at around 14 months of age, and has virtually eradicated the disease. However, recent scares linking the vaccine to autism and bowel disease have reduced the uptake of the jab, and UK public health experts have warned that another epidemic is possible.
Diarrhoeal Diseases
Poor hygiene and water supplies are the main factors behind the spread of diseases like dysentery and cholera. Both, although quite treatable, cause death through dehydration, as the body cannot replace the water and body salts it loses through diarrhoea attacks. All are far more prevalent in developing countries, which may have no efficient sewage disposal system, leading to the contamination of water supplies.
Acute respiratory infections
One of the most dangerous forms is Pertussis, or Whooping Cough, which is prevented in many parts of the world by a vaccination.
There are a very great number of infectious diseases due to infection with bacteria and viruses and the following are just some of the more common ones found worldwide.
Malaria
Malaria is a public health problem in some 90 countries, and causes between 1.5 and 2.7 million deaths world-wide each year.
AIDS
AIDS, or Acquired Immune Deficiency Syndrome, is linked to HIV virus, which can be passed from human to human through blood to blood contact.
Tuberculosis
Tuberculosis is usually thought of as a lung disease but can affect almost every organ in the body. It kills many people world-wide, particularly children and is increasingly common in the UK, with many of the 11 cases per 100,000 population of coming from people recently returned from trips abroad or in people settling in the UK from areas where TB is endemic.
Measles
Measles was prevalent among children in the UK until recent years - the last mini-epidemic was in the late 1980s. But the disease, characterised by the red skin rash and high temperatures, can cause permanent disability or even kill. Worryingly, since the MMR vaccination scare, lower levels of vaccination in the UK have caused several outbreaks of measles in susceptible groups of children, and sadly, deaths of affected children.
Diarrhoeal Diseases
Poor hygiene and water supplies are the main factors behind the spread of diseases like dysentery and cholera.
Acute respiratory infections
These can range from simple coughs and colds to various types of pneumonia.
Top
Causes and risk factors
Malaria
Malaria is caused by a parasite, Plasmodium, of which there are several varieties, which is passed on from infected humans when they are bitten by mosquitoes, which then go on to bite non-infected people. Malaria is a public health problem in some 90 countries, and causes between 1.5 and 2.7 million deaths world-wide each year.
In developing countries, where poorer nutrition and living conditions have reduced children's natural immune response to the parasite infection, it is fatal far more often.
AIDS
AIDS is commonly spread by unprotected sexual intercourse, both homosexual and heterosexual, and is a major killer in developing countries, where there is a higher degree of infection in the heterosexual community, and less use of protection such as condoms. In these countries, immune resistance is generally lower due to poorer nutrition and general health, and consequently, the development of full-blown AIDS, and death from opportunistic infections is far swifter.
Tuberculosis
Tuberculosis is caused by bacterial infection, mycobacterium tuberculosis. It is often linked to AIDS and HIV illness, as it is common in patients with reduced immunity.
Measles
Measles is due to a virus and is spread by droplet infection. Children in some areas of the world, such as parts of Africa, are much more susceptible to infection than in the developed world.
Diarrhoeal Diseases
Poor hygiene and water supplies are the main factors behind the spread of diseases like dysentery and cholera. Both, although quite treatable, cause death through dehydration, as the body cannot replace the water and body salts it loses through diarrhoea attacks. All are far more prevalent in developing countries, which may have no efficient sewage disposal system, leading to the contamination of water supplies.
More recently, the breakdown of proper water treatment facilities in eastern European countries such as Latvia has led to outbreaks of diseases like cholera. In the UK, the past decade has seen a vast increase in the number of food poisoning cases reported to the authorities. Again, these are rarely fatal, although the potent 0157 strain of the E.coli bacterium killed many elderly or sick patients during a recent Scottish outbreak.
Acute respiratory infections
Pneumonia is caused by viruses, bacteria and parasites. Many respiratory tract infections are very infectious, particularly in the early stages, and can be spread through droplets from sneezes or coughs, or from dirty tissues or water glasses.
Top
Symptoms
Malaria
The symptoms are bouts of fever, tiredness, headache, nausea, and muscular pain, leading, without treatment, to delirium, convulsions and death.
AIDS
Although HIV is symptomless, over time, it reduces the body's ability to deal with outside infections. When the body's immune system has been rendered ineffective, it is highly vulnerable to other predatory infections, such as TB, which may have already been lying dormant.
Tuberculosis
The most common symptoms are a persistent cough, which may involve coughing up blood, fevers, night-sweats, weight loss and tiredness. Once contracted, it can lie dormant in the lung, only developing into the disease if the body's immune system weakess.
Acute respiratory infections
Pneumonia is a term used to refer to a variety of lung infections caused by viruses, bacteria and parasites. Common symptoms include fever, a cough, rapid breathing, chest pain, and perhaps a bluish or grey colour of the lips or fingertips, indicating that the body is not getting enough oxygen through the lungs.
Top
Treatment and prevention
Malaria
If treated promptly, it is a curable disease, and travellers are advised to take a course of anti-malaria drugs to protect them before going abroad. However, nothing can provide 100% protection against malarial infection.
AIDS
Although once full-blown AIDS has developed, it becomes increasingly difficult to treat these infections. The HIV-positive stage can be lengthened by many years using modern anti-viral treatments.
Tuberculosis
Treatment is by a six-month course of antibiotics, and provided this is followed, the cure rate is high. However, symptoms generally disappear long before the end of the treatment course, and the failure of many people to continue for the full six months has been blamed for the emergence of TB strains resistant to antibiotics. The BCG vaccine is no longer given routinely to school age children in the UK due to the drastically reduced infection rate but is given selectively to babies and other children considered at risk of infection.
Measles
In this country, the MMR (Measles, mumps and rubella) vaccination is given at around 14 months of age, and has virtually eradicated the disease. However, recent scares linking the vaccine to autism and bowel disease have reduced the uptake of the jab, and UK public health experts have warned that another epidemic is possible.
Diarrhoeal Diseases
Poor hygiene and water supplies are the main factors behind the spread of diseases like dysentery and cholera. Both, although quite treatable, cause death through dehydration, as the body cannot replace the water and body salts it loses through diarrhoea attacks. All are far more prevalent in developing countries, which may have no efficient sewage disposal system, leading to the contamination of water supplies.
Acute respiratory infections
One of the most dangerous forms is Pertussis, or Whooping Cough, which is prevented in many parts of the world by a vaccination.