Dengue fever and dengue hemorrhagic fever (DHF) are acute febrile diseases, found in the tropics and Africa, and caused by four closely related virus serotypes of the genus Flavivirus, family Flaviviridae. The geographical spread is similar to malaria, but unlike malaria, dengue is often found in urban areas of developed tropical nations, including Singapore, Taiwan, Indonesia, India and Brazil. Each serotype is sufficiently different that there is no cross-protection and epidemics caused by multiple serotypes (hyperendemicity) can occur. Dengue is transmitted to humans by the Aedes aegypti (rarely Aedes albopictus) mosquito, which feeds during the day.
Causes:
Dengue fever is caused by any one of four dengue viruses spread by the Aedes aegypti mosquito. These mosquitoes thrive in and near human habitations where they breed in even the cleanest water.
Mosquitoes transmit the virus back and forth between humans. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito's bloodstream. It then circulates before settling in the salivary glands. When the infected mosquito then bites another person, the virus enters that person's bloodstream, where it may cause the serious illness.
You can become infected with dengue fever more than once. This happens when you're exposed to a different one of the four dengue viruses than one to which you were previously exposed. Infection a second time is typically what causes the more severe form of the disease — dengue hemorrhagic fever.
Symptoms:
Signs and symptoms of dengue fever usually begin four to seven days after you've been bitten by a mosquito carrying a dengue virus. These signs and symptoms can vary, depending on the form of the disease. More severe forms of the disease usually begin the same way as the mild form (dengue fever), then become worse after several days.
Dengue fever signs and symptoms typically include:
High fever, up to 105 F, A rash over most of your body, which may subside after a couple of days and then reappear, Severe headache, backache or both, Pain behind your eyes, Severe joint and muscle pain, Nausea and vomiting, etc.
Dengue fever rarely causes death, and symptoms usually get better after five to seven days.
Dengue hemorrhagic fever — a more severe form of the disease — can also cause:
* Significant damage to your blood and lymph vessels.
* A decrease in the number blood cells that help your blood clot (platelets).
* Bleeding from the nose, mouth and under the skin, creating the appearance of bruising.
* Death.
Dengue shock syndrome — the most severe form of the disease — may also cause:
* Blood vessel fluid (plasma) leakage.
* Heavy bleeding.
* A sudden drop in blood pressure (shock).
* Death.
Diagnosis:
Diagnosing dengue fever can be difficult. That's because its signs and symptoms can be easily confused with those of other diseases, such as malaria, leptospirosis and typhoid fever. Still, diagnosis of dengue fever is typically done by evaluating your signs and symptoms along with your medical and travel history. To diagnose your condition, your doctor will likely ask about these. In addition, your blood may be tested for evidence of a dengue virus.
Medical history
Your doctor will likely ask about your medical and travel history and any exposure to mosquitoes. Be sure to describe international trips in detail, including the countries you visited and the dates, as well as any contact you may have had with mosquitoes.
Blood tests
Laboratory tests, usually using a sample of your blood, are needed to confirm a diagnosis of dengue fever. If you have dengue fever, your blood may reveal the virus itself. If not, blood tests known as hemagglutination inhibition (HI) assay, enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR) also can detect antigens, antibodies or nucleic acids specific to the viruses. These tests may take several days.
Treatment:
No specific treatment for dengue fever exists.
If you have a mild form of the disease, your doctor will recommend making sure to drink enough fluids to avoid dehydration from vomiting and high fever. You can also take acetaminophen (Tylenol, others) for pain and fever. Avoid aspirin or other nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil, Motrin, others) and naproxen sodium (Aleve). These can increase the risk of bleeding complications.
If you have a more severe form of the disease, treatment consists of supportive care in a hospital. Such care includes intravenous fluids and electrolyte replacement, maintaining adequate blood pressure and replacing blood loss.
If you have any form of dengue fever, you may also be kept away from mosquitoes, to avoid transmitting the disease to others.
Causes:
Dengue fever is caused by any one of four dengue viruses spread by the Aedes aegypti mosquito. These mosquitoes thrive in and near human habitations where they breed in even the cleanest water.
Mosquitoes transmit the virus back and forth between humans. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito's bloodstream. It then circulates before settling in the salivary glands. When the infected mosquito then bites another person, the virus enters that person's bloodstream, where it may cause the serious illness.
You can become infected with dengue fever more than once. This happens when you're exposed to a different one of the four dengue viruses than one to which you were previously exposed. Infection a second time is typically what causes the more severe form of the disease — dengue hemorrhagic fever.
Symptoms:
Signs and symptoms of dengue fever usually begin four to seven days after you've been bitten by a mosquito carrying a dengue virus. These signs and symptoms can vary, depending on the form of the disease. More severe forms of the disease usually begin the same way as the mild form (dengue fever), then become worse after several days.
Dengue fever signs and symptoms typically include:
High fever, up to 105 F, A rash over most of your body, which may subside after a couple of days and then reappear, Severe headache, backache or both, Pain behind your eyes, Severe joint and muscle pain, Nausea and vomiting, etc.
Dengue fever rarely causes death, and symptoms usually get better after five to seven days.
Dengue hemorrhagic fever — a more severe form of the disease — can also cause:
* Significant damage to your blood and lymph vessels.
* A decrease in the number blood cells that help your blood clot (platelets).
* Bleeding from the nose, mouth and under the skin, creating the appearance of bruising.
* Death.
Dengue shock syndrome — the most severe form of the disease — may also cause:
* Blood vessel fluid (plasma) leakage.
* Heavy bleeding.
* A sudden drop in blood pressure (shock).
* Death.
Diagnosis:
Diagnosing dengue fever can be difficult. That's because its signs and symptoms can be easily confused with those of other diseases, such as malaria, leptospirosis and typhoid fever. Still, diagnosis of dengue fever is typically done by evaluating your signs and symptoms along with your medical and travel history. To diagnose your condition, your doctor will likely ask about these. In addition, your blood may be tested for evidence of a dengue virus.
Medical history
Your doctor will likely ask about your medical and travel history and any exposure to mosquitoes. Be sure to describe international trips in detail, including the countries you visited and the dates, as well as any contact you may have had with mosquitoes.
Blood tests
Laboratory tests, usually using a sample of your blood, are needed to confirm a diagnosis of dengue fever. If you have dengue fever, your blood may reveal the virus itself. If not, blood tests known as hemagglutination inhibition (HI) assay, enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR) also can detect antigens, antibodies or nucleic acids specific to the viruses. These tests may take several days.
Treatment:
No specific treatment for dengue fever exists.
If you have a mild form of the disease, your doctor will recommend making sure to drink enough fluids to avoid dehydration from vomiting and high fever. You can also take acetaminophen (Tylenol, others) for pain and fever. Avoid aspirin or other nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil, Motrin, others) and naproxen sodium (Aleve). These can increase the risk of bleeding complications.
If you have a more severe form of the disease, treatment consists of supportive care in a hospital. Such care includes intravenous fluids and electrolyte replacement, maintaining adequate blood pressure and replacing blood loss.
If you have any form of dengue fever, you may also be kept away from mosquitoes, to avoid transmitting the disease to others.
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