DENGUE
Causative Agent:
Dengue virus is caused by dengue fever and is a mosquito-borne virus. Dengue is a RNA positive-strand virus of the family Flaviviridae. Dengue is an enveloped virus, 40-60 nm in size. The dengue virus is mostly spherical in shape.
Dengue virus is caused by dengue fever and is a mosquito-borne virus. Dengue is a RNA positive-strand virus of the family Flaviviridae. Dengue is an enveloped virus, 40-60 nm in size. The dengue virus is mostly spherical in shape.
History:
The first record of a case of dengue fever is from the Jin Dynasty (265–420 AD) which referred to a “water poison” associated with flying insects. The first recognised dengue epidemics occurred in Asia, Africa, and North America in the 1780s, shortly after the naming of the disease in 1779. The viral transmission by mosquitoes was only discovered in the 20th century. Before then there had not been a real known cause of the transmission.
The first record of a case of dengue fever is from the Jin Dynasty (265–420 AD) which referred to a “water poison” associated with flying insects. The first recognised dengue epidemics occurred in Asia, Africa, and North America in the 1780s, shortly after the naming of the disease in 1779. The viral transmission by mosquitoes was only discovered in the 20th century. Before then there had not been a real known cause of the transmission.
Epidemiology:
The dengue virus is transmitted to humans from an infected mosquito. Only a mosquito which carries the virus can transmit it to an organism. When a mosquito bites a person who has dengue virus in his or her blood, the mosquito becomes infected with the dengue virus. An infected mosquito can later transmit that virus to healthy people by biting them. Dengue cannot be spread directly from one person to another, and mosquitoes are necessary for transmission of the dengue virus.
However not all mosquitos can carry the virus, only mosquitos in the genus Aedes is responsible for the dengue transmission and epidemics. Aedes mosquitos are found in tropical and subtropical regions all over the world. Today about 2.5 billion people, or 40% of the world’s population, live in areas where there is a risk of dengue transmission. Dengue is found in at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean. The World Health Organization estimates that 50 to 100 million infections occur yearly.
The dengue virus is transmitted to humans from an infected mosquito. Only a mosquito which carries the virus can transmit it to an organism. When a mosquito bites a person who has dengue virus in his or her blood, the mosquito becomes infected with the dengue virus. An infected mosquito can later transmit that virus to healthy people by biting them. Dengue cannot be spread directly from one person to another, and mosquitoes are necessary for transmission of the dengue virus.
However not all mosquitos can carry the virus, only mosquitos in the genus Aedes is responsible for the dengue transmission and epidemics. Aedes mosquitos are found in tropical and subtropical regions all over the world. Today about 2.5 billion people, or 40% of the world’s population, live in areas where there is a risk of dengue transmission. Dengue is found in at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean. The World Health Organization estimates that 50 to 100 million infections occur yearly.
Pathology:
When an infected mosquito feeds on a person, it injects the dengue virus into the bloodstream. Dengue fever causes a decrease in the number of white blood cells and platelets in the blood. There is a virus called dengue hemorrhagic fever which is much worse than dengue fever and causes the most deaths. A person with severe dengue hemorrhagic fever can experience leakage of blood plasma out of the capillaries which causes fluids to collect in body. The may also experience severe bleeding in the stomach and intestines which causes death. The time period of incubation for the virus is 10-14 days, followed by up to a week of symptoms, and then by a few days of recovery. The hemorrhagic symptoms, when they occur, tend to occur in near the end of the first week after noticing symptoms and usually results in death
When an infected mosquito feeds on a person, it injects the dengue virus into the bloodstream. Dengue fever causes a decrease in the number of white blood cells and platelets in the blood. There is a virus called dengue hemorrhagic fever which is much worse than dengue fever and causes the most deaths. A person with severe dengue hemorrhagic fever can experience leakage of blood plasma out of the capillaries which causes fluids to collect in body. The may also experience severe bleeding in the stomach and intestines which causes death. The time period of incubation for the virus is 10-14 days, followed by up to a week of symptoms, and then by a few days of recovery. The hemorrhagic symptoms, when they occur, tend to occur in near the end of the first week after noticing symptoms and usually results in death
Response and Treatment:
The dengue virus infected cells produce and release small proteins called interferons. Interferons help the immune system recognise dengue-infected cells and help protect uninfected cells from the disease. As the immune system fights the dengue infection, the person experiences a fever.
There is no specific medicine or antibiotic to cure dengue fever, the only treatment is to treat the symptoms. For typical dengue, the treatment is just the curing of the symptoms and rest while drinking plenty of water. Most cases of dengue fever are fixed within two weeks to three weeks. Hospital admission is usually needed if the person develops dengue haemorrhages fever.
The best way to prevent being infected with the dengue virus is to avoid mosquito bites. This can be done by:
The dengue virus infected cells produce and release small proteins called interferons. Interferons help the immune system recognise dengue-infected cells and help protect uninfected cells from the disease. As the immune system fights the dengue infection, the person experiences a fever.
There is no specific medicine or antibiotic to cure dengue fever, the only treatment is to treat the symptoms. For typical dengue, the treatment is just the curing of the symptoms and rest while drinking plenty of water. Most cases of dengue fever are fixed within two weeks to three weeks. Hospital admission is usually needed if the person develops dengue haemorrhages fever.
The best way to prevent being infected with the dengue virus is to avoid mosquito bites. This can be done by:
- Avoid outdoor activity, particularly around dusk and dawn when mosquitoes are most active.
- Wear suitable clothing
- Wear mosquito repellent
- Use a bed net
- Stay in air-conditioned accommodation with fly screens on the windows