Dengue

Dengue is a viral disease caused by the dengue virus, which has four serotypes (DEN-1, DEN-2, DEN-3 and DEN-4). It is transmitted by the bite of an infected Aedes aegypti mosquito: infection always occurs through a mosquito bite, never directly from one person to another.

Aedes aegypti is black with white stripes on its legs and abdomen, and it lays its eggs in containers that collect water. That is why the spread of the virus is linked to the presence of mosquito breeding sites in and around homes.

According to the Ministerio de Salud de la Nación (Argentina's national Ministry of Health), dengue should be suspected when there is a fever (38 °C or higher) together with any of these symptoms: headache and/or pain behind the eyes, muscle and/or joint pain, nausea, vomiting and/or diarrhea, general malaise, and a skin rash.

There are warning signs that may appear during the fever or after it goes down, and that require immediate medical attention: severe abdominal pain, irritability, drowsiness and/or lethargy, bleeding from mucous membranes (gums, nose, etc.), persistent vomiting and difficulty breathing.

These tests do not replace a medical visit. If you have severe, continuous belly pain, vomiting that won't stop, bleeding from your gums or nose, a lot of drowsiness or irritability, shortness of breath, or you feel dizzy or faint when you stand up, go to the emergency room right away, without waiting for the result. These signs can appear when the fever goes down. For fever, take only paracetamol (acetaminophen): do not take aspirin, ibuprofen, diclofenac or ketorolac, and do not get intramuscular injections. If you are pregnant, the patient is a baby, you are over 65 or you have a chronic illness, see a doctor the same day. If you have symptoms consistent with dengue, see your doctor and drink plenty of fluids.

The right test depends on how many days have passed since the fever began. In the early phase (roughly the first 7 days) the virus is present in the blood, so RT-PCR (detection of the virus's genetic material) and the NS1 antigen are used. RT-PCR performs best in the first days of symptoms.

In the later phase, antibodies appear. IgM becomes detectable around the fourth to fifth day after symptoms begin and can remain positive for 2 to 3 months; IgG appears later and can persist for a long time, indicating previous contact with the virus or vaccination. That is why, after the first few days, serology (IgM/IgG) becomes more useful.

Keep in mind that a negative NS1 or PCR result does not, on its own, rule out infection, especially near the end of the early window. Interpreting the results and deciding which test to perform should always be left to your doctor.

The most effective way to stop transmission is to eliminate or neutralize mosquito breeding sites. Check your home and its surroundings (patios, yards, roofs and gutters) and get rid of all unused containers that can collect water, such as cans, bottles and tires (a clean-up known in Argentina as descacharrado).

Turn over, cover or put away any objects left outdoors that can collect rain or irrigation water (buckets, basins, drums, toys), and place mosquito netting over drain grates. These tasks should be kept up all year round.

To avoid bites, use repellent properly and reapply it as directed on the product label, along with other personal protection measures.