Dengue is a viral infection caused by four types of viruses (DENV-1, DENV-2, DENV-3, DENV-4) belonging to the Flaviviridae family. The viruses are transmitted through the bite of infected Aedes aegypti and Aedes albopictus female mosquitoes that feed both indoors and outdoors during the daytime (from dawn to dusk).
These mosquitoes thrive in areas with standing water, including puddles, water tanks, containers and old tires. Lack of reliable sanitation and regular garbage collection also contribute to the spread of the mosquitoes.Dengue occurs in urban and suburban settings with higher transmission rates happening during the rainy season.
Dengue infection may be asymptomatic or subclinical. in some cases where persons may not exhibit symptoms. Those with symptoms get ill between 4 to 7 days after the bite. The infection is characterized by flu-like symptoms which include a sudden high fever coming in separate waves, pain behind the eyes, muscle, joint, and bone pain, severe headache, abnormal taste sensation and a skin rash with red spots. Treatment includes supportive care of symptoms. there is no specific medicine or antibiotic to treat it. For typical dengue fever, the treatment is directed toward relief of the symptoms (symptomatic treatment).
The illness may progress to Dengue Hemorrhagic Fever (DHF). Symptoms include severe abdominal pain, vomiting, diarrhea, convulsions, bruising, and uncontrolled bleeding. High fever can last from 2 to 7 days.
The complications of dengue fever are usually associated with the more severe forms of dengue fever: hemorrhagic and shock
syndrome. The most serious complications, although infrequent, are as follows:
Low white blood cell count
Low blood pressure (hypotension)
Slow heart rate (bradycardia)
Neurological damage (seizures, encephalitis)
Dengue PCR test – can detect dengue virus up to day 10 of the illness and should be ordered in suspected cases as early as possible in the course of the illness.
Dengue NS1 antigen – can detect dengue virus up to day 10 of the illness and should be ordered in suspected cases as early as possible in the course of the illness.
Serology tests – Serum IgM appears after 4–5 days of infection. Serum IgG doesnot become positive until about the seventh day of the illness. A patient whose serum is IgG positive for dengue early in their illness has probably been previously exposed to another serotype of dengue.
Treatment of Dengue
There is no known cure for dengue. However, your doctor may prescribe medication such as Acetaminophen that can help relieve pain and reduce fever. If you are suffering from dengue haemorrhagic fever, the doctor may recommend:
- Blood pressure monitoring
- Supportive care in a hospital
- IV fluid and electrolyte replacement
- Transfusion to replace blood loss
Vaccinations for dengue – The number of vaccines are currently under experimental situations and some of them are successful in early studies and further results are promising . However non of the vaccinations are still lodged for population use due to number of shortcomings.
Vaccination and antiviral treatments are still a several steps ahead , therefore mosquito control is the main and effective way to reduce the risk of dengue infection. The preventing measures includes
preventing mosquitoes from accessing egg-laying habitats by environmental management and modification;
disposing of solid waste properly and removing artificial man-made habitats;
covering, emptying and cleaning of domestic water storage containers on a weekly basis;
applying appropriate insecticides to water storage outdoor containers;
using of personal household protection such as window screens, long-sleeved clothes, insecticide treated materials, coils and vaporizers;
improving community participation and mobilization for sustained vector control;
applying insecticides as space spraying during outbreaks as one of the emergency vector-control measures
active monitoring and surveillance of vectors should be carried out to determine effectiveness of control interventions. S.W