Dengue: what you need to know about the disease | WH3 – System 103 – Radio Ray of Light – Radio Leader

Priscila Rodrigues Garrido Bratkowski, Infectologist / Disclosure

In recent weeks, there has been a significant increase in the number of cases of dengue in the HRTGB and in the region. Let’s talk about it.

A little of history

The Aedes aegypti mosquito emerged in Africa and from there it spread to Asia and the Americas, mainly through maritime traffic. In Brazil, it arrived during the 18th century, probably on vessels that transported slaves (the so-called slave ships).

There are reports of dengue epidemics as early as 1916, in São Paulo, and in 1923, in Niterói. The mosquito was considered eradicated in the 1950s, but was reintroduced into the country from neighboring countries.

More recently, the disease in Brazil presents endemic and epidemic cycles, with explosive epidemics occurring every 4 or 5 years.

Epidemiological data

In the last ten years, in addition to the high number of cases, an increase in the severity of the disease and, consequently, hospitalizations have been observed.

In Santa Catarina since the beginning of 2022, there has been a large increase in dengue cases, especially in the West region. The state showed a 144% increase in the number of notifications of suspected cases compared to the same period in 2021, and a 108% increase in the number of confirmed cases of the disease.

Among the confirmed cases of dengue, 22 showed warning signs and 10 deaths were recorded, four confirmed and six still under investigation by the Municipal Health Departments.

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or mosquito

Dengue transmission occurs during the bite of a female Aedes aegypti mosquito infected with the virus.

The mosquito lives in urban areas and has diurnal habits, that is, hematophagy (feeding), copulation (reproduction) and oviposition (egg laying) occur during the day.

Eggs are laid in clusters millimeters above the surface of the water (not directly into it). When it rains, the water level rises, comes into contact with the eggs and these hatch in a few minutes. In a period that varies between five and seven days, the larva passes through four stages until it gives rise to a new mosquito, which lives for 15 to 20 days.

The female feeds on human blood every 3 days on average to mature her eggs. An infected female may have several short blood feeds on different hosts, thus spreading the virus.

Once contaminated with the dengue virus, after an incubation period of 8 to 12 days, the female becomes a permanent vector of the disease. It is estimated that there is a probability between 30 and 40% of chances that their offspring will also be born infected.

The virus and its manifestations

The dengue virus has four serotypes called DENV-1, DENV-2, DENV-3 and DENV-4

After the bite, symptoms can appear between four and 10 days. The infection is not spread by direct contact with infected people.

When it causes symptoms, the first manifestation of dengue is high fever of sudden onset, which lasts from two to seven days, associated with headache, weakness, body, joint and back pain. Spots on the body are present in 50% of cases, and there may be associated itching. Loss of appetite, nausea and vomiting may also be present.

With regard to the most severe form, known as dengue hemorrhagic fever, the condition worsens on the third or fourth day of evolution, with the appearance of hemorrhagic manifestations and circulatory collapse. Some patients may also have neurological manifestations, such as seizures and irritability.

It is important to observe the presence of warning signs (persistent vomiting, abdominal pain, postural hypotension, bleeding and restlessness) and, in the presence of these, seek medical attention immediately.

diagnosis and treatment

The disease is confirmed by a blood test (NS1 antigen or IgM/IgG antibody test).

There is no specific effective remedy against the dengue virus. Treatment is based on analgesics and antipyretics and can be done at home. Hydration is indicated with increased intake of water and liquids such as juices, teas, homemade serums. Medications with acetylsalicylic acid (ASA) should not be used, as they increase the risk of bleeding. Dengue hemorrhagic fever should be managed in a hospital setting.

disease prevention

Once the mosquito outbreaks are already installed and the virus has already spread, as an individual protection measure, the use of repellents is suggested.

Repellents should be applied to exposed areas of the body and can be used over clothing as well. Remember to reapply according to the indication of each manufacturer and in case of excessive sweating or contact with water. There is no contraindication for use in pregnant women, as long as the product is registered with ANVISA.

The use of repellents in children requires some care. The product should not be used on children under 6 months. From 6 months to 2 years, those based on IR3535 can be used. Above that age, repellents based on icardine and DEET can also be used, observing the concentration of the product. Use should be restricted to 3 times a day, remembering that you should never apply the repellent directly on the face.

As a collective protection measure and prevention of new outbreaks, we must all strive to reduce the infestation by the Aedes aegypti mosquito. For this, we suggest:

• avoid using dishes in potted plants. If using them, fill with sand to the brim;

• store bottles with the neck facing downwards;

• keep trash cans covered;

• keep the water tanks always sealed, without any opening, especially the water tanks;

• avoid plants such as bromeliads, as they accumulate water;

• treat the pool water with chlorine and clean it once a week;

• keep drains closed and unclogged;

• brush the animals’ food and water pots at least once a week;

• remove water accumulated on slabs;

• flush, at least once a week, in seldom used toilets;

• keep the toilet lid closed;

• avoid accumulating rubble in vacant lots;

• report the existence of possible outbreaks of Aedes aegypti to the Municipal Health Department.

Terezinha Gaio Basso Regional Hospital of São Miguel do Oeste

Priscila Rodrigues Garrido Bratkowski, Infectologist – CRM – SC 16927|RQE 9386

Technical Director – Katia Bugs – Physician – CRM 10375 – Nephrologist – RQE 5333

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