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Experiencing the symptoms of a fever can be frightening - the condition is commonly associated with a number of serious diseases, and it’s easy to assume that your fever is the first sign of an illness like malaria, cholera or dysentery.
Fevers aren't always a cause for concern though. In fact, fevers are a natural response to the presence of infectious organisms - designed to raise your core temperature and speed up the body’s own immune response.
Depending on which part of the world you are in, the common conditions that can trigger a fever include:
Many of these conditions can be treated with the help of a doctor and you may be able to treat some illnesses, such as the flu, yourself. You will find detailed information about the common causes of fever below, as well as advice on how to treat each condition.
A fever is an increase in body temperature, often due to an illness. Fevers actually help your body to fight off infections by increasing the efficiency of your immune system and making it harder for certain viruses or bacteria to survive.
Normal body temperature varies from person to person but a temperature over 100.4 F (38 C) is generally accepted as a fever.
If you’re running a fever, try not to panic. There is a good chance that your body is in the process of fighting off a condition like the flu, and that your immune system is already coping with the problem.
Make sure that you get plenty of rest, stay hydrated and consider taking an antipyretic medication like paracetamol, which should help to bring down your fever.
You should always try to see a doctor though. Fever can be a symptom of several serious medical conditions, and it’s important to rule out diseases like dysentery, tuberculosis or malaria before they can progress.
The treatment for some of the conditions that cause fever are time sensitive too, so it’s always better to act quickly.
You can read more about the different causes and treatment options below.
Flu, or influenza, is a highly contagious infection caused by a virus. Data collected by the World Health Organisation (WHO) shows that approximately 5-15% of the global population catches flu every year. The condition is very contagious, and is spread by coughs and sneezes.
The symptoms of flu can make you feel too unwell to continue your normal activities such as going to work.
In most cases, flu is not a cause for concern. Although the infection does cause rapid fevers and generally achy muscles, most healthy people will make a full recovery without medical intervention.
Resting, keeping warm and drinking plenty of fluid should help you to manage the worst of the symptoms. Medications like paracetamol or ibuprofen can also be used to manage pain or reduce your fever.
Most cases of the flu resolve themselves within 7-10 days. That said, young children, pregnant women, people over 65 or anyone suffering from another medical condition should still book an appointment with a doctor as you are at higher risk of developing complications from the flu.
If you have the flu for more than 10-14 days, there is a risk of complications. Sometimes, the flu can cause chest infections or pneumonia, so if you find that your symptoms aren’t subsiding you should seek medical attention.
Your doctor may be able to prescribe antiviral medications, or antibiotics if the condition has triggered a bacterial infection. Your doctor will also be able to give you help and advice about managing the condition.
People who are in the ‘at risk’ categories, including:
Should also see a doctor to ensure that the condition is managed correctly.
Find more information about the flu in our Health A-Z
Pneumonia is a condition that causes inflammation of soft tissue in the lungs. It is generally triggered by a bacterial infection.
According to data published in the BMJ, there are 151 million new cases of pneumonia every year. The condition can affect anyone, but it is particularly prevalent in the developing world.
Pneumonia is also known to be one of the leading causes of childhood mortality. In fact, data published by the WHO shows that pneumonia accounts for around 16% of all deaths of children under 5 years old.
If you think you - or your child - might be suffering from pneumonia, you should book an appointment with your doctor immediately. They will be able to diagnose the condition correctly and provide proper treatment options.
In most cases, pneumonia is treated with a course of antibiotics, plenty of rest and plenty of fluids. This is normally enough to get rid of the underlying infection, and the rest of the symptoms will pass with time.
Learn more about pneumonia in our Health A-Z
If you are suffering from severe symptoms such as rapid breathing, chest pain or confusion then you should see a doctor urgently.
Certain groups of people are at risk of developing severe pneumonia and may require hospital treatment. These include:
If left untreated, pneumonia can cause a number of serious side effects, including pleurisy, lung abscesses or septicemia.
Dengue, or dengue fever, is a viral infection that’s spread by mosquitoes. Data published in the Journal of Health Research and Reviews shows that there are around 390 million cases of dengue per year.
The disease is becoming more widespread in tropical and subtropical regions of the world too. In fact, the WHO estimate that the number of cases doubled between 2015 and 2016.
Dengue isn’t always a cause for concern. Healthy individuals who contract the infection may find that their symptoms pass within a week. Bed rest and plenty of fluids will also help to speed up your recovery.
You should still see a doctor if you think you have dengue though. In approximately 5% of cases, the infection can progress - triggering something called dengue shock syndrome or DSS.
DSS is a much more serious condition that causes internal bleeding, and the buildup of fluid within the abdomen. People who develop DSS can suffer from multi-organ failure, and will require immediate medical attention.
If you think you have dengue you should always see a doctor as soon as possible so that the condition can be diagnosed and to rule out other causes.
If you think you have dengue and you notice that you are:
You should seek immediate medical attention, to rule out the development of DSS. Young children with dengue, and people who have previously suffered from the disease, are thought to be particularly susceptible to DSS too.
Find more about dengue in our Health A-Z
Tuberculosis (or TB) is a bacterial infection that normally affects the lungs. According to the WHO, there were over 10.4 million cases of tuberculosis in 2016, with developing countries like South Africa, Sri Lanka, India and Pakistan being the worst affected.
Tuberculosis can lie dormant for a number of years, which means that there is no real way of knowing whether or not you have contracted the disease. When it moves into its active stage, TB progresses rapidly; attacking the lungs, and causing relatively severe symptoms in a short space of time.
If you think you are suffering from active TB, you should seek medical attention immediately. The condition can be treated using a number of different antibiotics, and recovery generally takes several months.
You should also avoid contact with other people as much as possible if you think you have active TB. The condition is highly contagious, and spreads whenever you cough or sneeze.
Learn more about tuberculosis in our Health A-Z
If your fever is accompanied by severe chest pain, difficulty breathing or a persistent cough, you should seek medical attention immediately.
You should also see a doctor if you’ve had a cough for more than three weeks, or you’ve coughed up blood within the last 24-48 hours.
As long as it is caught in the early stages, active tuberculosis can be treated using antibiotics, and most cases do result in a full recovery if the antibiotic regime is completed properly.
Cholera is a waterborne infection caused by a bacteria that targets the small intestine. You can contract cholera by eating or drinking anything that has been contaminated by contact with the Vibrio cholerae bacterium.
Cholera is most prevalent in the developing world, with 54% of all cases being localised to sub-Saharan Africa, and 32% of cases originating in Hispaniola.
The symptoms of cholera include:
In some cases the symptoms of the disease can be quite mild, but some people will suffer from severe vomiting or diarrhea.
If you think you have contracted cholera and you are suffering from severe diarrhea, you should seek immediate medical attention. Cholera can cause severe dehydration, and needs to be treated using special oral rehydration solutions (ORSs).
These treatments are available at many pharmacies, and combine large amounts of water with the salts and sugars needed to prevent electrolyte imbalance.
Mild cases of cholera can be managed by drinking plenty of fluids, and waiting for the infection to pass.
More serious cases will require medical intervention to ensure that you receive enough hydration. If you have suffered with severe diarrhea for more than 7 days, or vomiting for more than 2 days, you should book an appointment with your doctor immediately.
Children, the elderly and people suffering from any immune-compromising medical conditions should also seek immediate medical attention.
Find more about cholera in our Health A-Z
Dysentery is a highly contagious infection that affects the intestines. Dysentery can be caused by two separate organisms: The shigella bacteria, or Entamoeba Histolytica - a single-celled amoeba found in tropical regions of the world.
According to a study published in the BMJ, dysentery is thought to be the cause of 40% of all cases of diarrhea in the parts of the world that Entamoeba Histolytica organisms are found.
The symptoms of dysentery include:
For fit and healthy individuals, dysentery can be managed without medical intervention. That said, you should always see a doctor as the symptoms of dysentery are similar to a number of more serious medical conditions, and it is important to be diagnosed properly.
Drinking plenty of fluids, taking oral rehydration solutions and resting will help the infection to pass. Painkillers like paracetamol or ibuprofen can be used to help manage fever symptoms too.
Dysentery is highly contagious though, so it is important that you wait for at least 48 hours after your last bout of diarrhea before coming into contact with anyone else.
It is also important that you avoid taking any anti-diarrhoea medication, as this will stop your body from passing the infection.
People with a weakened immune system, young people, old people or pregnant people are at much higher risk of serious complications, and should see a doctor immediately. Malnourished people are also at risk of suffering complications as a result of dysentery.
Generally speaking, there’s no need to worry unless your symptoms have lasted for more than 7 days. That said, you should always see a doctor if there is blood in your stool. They will help you to rule out other causes, and provide you with advice on treating the condition.
Young people, elderly people, pregnant women or people suffering from other medical conditions are also at risk from dysentery. If you fall in to one of these categories, you should seek immediate medical attention.
Learn more about dysentery in our Health A-Z
Malaria is an infectious disease caused by a single-celled parasite. Malaria is very common in sub-Saharan Africa and other parts of the developing world. Of the 212 million cases reported in 2015, roughly 80% occurred in countries in sub-Saharan Africa, or in India.
However, studies have shown that the disease is less common than people think. A paper published in Tropical Medicine and International Health showed that 43% of people with a fever thought that Malaria was responsible for the condition, but only 2% of participants were actually suffering from malaria.
Symptoms can take between 5 and 25 days to show.
It’s always important to confirm that you have malaria before you try to treat the condition. Failure to do so may cause failure to treat the actual cause of your fever, and the overuse of malaria medications, which increases the chances of medication resistance in some strains of the parasite.
Once you have a definite diagnosis, a doctor will be able to help you treat the condition with antimalarial medications. These are normally oral medications, although some may be delivered intravenously.
Malaria is a very treatable but the disease can progress quite rapidly. If you think you might be suffering from malaria, you should seek immediate medical attention.
A clinic or hospital should be able to help you diagnose the condition, and your doctor will be able to recommend the correct antimalarial drugs.
Pregnant women, children and people with a weakened immune system are at increased risk of complications from malaria.
Learn more about Malaria in our Health A-Z
There are other, less common causes of fever - including some cancers, the common cold, a number of other, infectious diseases and conditions like rheumatoid arthritis.
If you are worried about your fever, or you’ve had the condition for more than three days you should always see a doctor. They will be able to rule out more serious causes, and help you to identify the reason for your fever.
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Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.