Dengue: Transmission, symptoms and control

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Photo by Kevin Grieve on Unsplash

Written by Dr. Shyam Sundar Gupta, PhD, Medically Reviewed by Dr. Ajay Kumar Tiwari, MD (Ay.)

Dengue is transmitted between humans through the bites of mosquitoes. The fast-expanding of dengue is a public health challenge due to unavailability efficient vaccines, drugs, or vector-control methods (1).

Transmission

The Aedes aegypti mosquito is the primary vector of dengue. The dengue virus is transmitted to humans through the bites of infected female mosquitoes. Infected humans are the chief carriers and multipliers of the dengue virus. The uninfected mosquitoes may access the dengue virus from infected humans. The infected people with the dengue virus are capable of transmitting the infection via Aedes mosquitoes. The peak biting periods of Aedes aegypti mosquito is early in the morning and in the evening before sunset (2).

Symptoms

After the incubation period of 4–10 days after the biting from an infected mosquito, symptoms generally occur in 2–7 days (3, 4).

WHO classified dengue infections into three groups in 2009 (3).

Dengue without warning signs: fever up to 40°C and two of the following symptoms:

  • Nausea or vomiting or both
  • Leukopenia (low white blood cells)
  • Aching and pains in arms and legs
  • Positive tourniquet test (a test performed by health center)
  • Pain behind the eyes

Dengue fever with warning signs:  fever and at least one of the following symptoms:

  • Abdominal pain
  • Continual vomiting
  • Mucosal bleeding from nose and gums
  • Sleepiness or restlessness
  • Enlarged liver
  • Increased haematocrit with decreasing blood platelets
  • Excess fluids in the lining of the lungs or the abdominal organs

Severe dengue: fever and at least one of the following symptoms:

  • Kidney malfunction
  • Rapid collection of fluid in the lungs
  • Low blood pressure and rapid heart rate
  • Severe bleeding
  • Drowsiness or even coma.

Complications of dengue

The main danger complication of dengue is major bleeding; brain or heart damage and multiple organ failure and it may cause death (3).

Diagnosis

After the starting of disease, the virus can be detected in circulating blood cells, serum, plasma, and other tissues for 4–5 days. During the early stages of illness, isolation of the virus, and detection of nucleic acid or antigen can be used to identify the infection. At the end of the acute phase of the disease, serological tests may be performed for diagnosis (5).

Treatment

There is no precise treatment for dengue. The researchers are working on drugs for the treatment of dengue and vaccines against dengue virus (3, 6). Patients should consult a doctor; take a rest and too much fluid.

  • Paracetamol can be taken to reduce fever and joint pains.
  • Aspirin or ibuprofen should be avoided since they can cause the risk of bleeding (3, 7).

The patient should consult the doctor in the case of severe dengue.

Vector control

The dengue virus-carrying mosquito frequently breeds in containers and receptacles having water. The breeding of mosquitoes may be reduced by the following ways.

  • Cover up water tanks, barrels, cisterns, garbage containers.
  • Remove water from old tyres, bottles, tin cans, bottles, trays.
  • Make sure and clean the flat roofs and clogged gutters where water may have settled.
  • Water should be changed frequently in pet water dishes, plant trays, and birdbaths.
  • Larvivorous fish (e.g. guppy) may be introduced into ornamental water features to eat mosquito larvae.
  • Weeds and tall grasses should be trimmed because adult mosquitoes look for these for shelter.

People should keep away from mosquitoes.

  • Put on full sleeves and pants.
  • Set up protected screens or nets to doors and windows to keep mosquitoes out.
  • Apply an insect repellent.
  • Use mosquito nets on the bed during sleeping or resting.
  • Insecticide sprays may be spread in high-risk areas.

Note: Please consult your family doctor before applying any health tips of Amrit Health Tips website (www.amrithealthtips.com).

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