Dengue: understand symptoms and warning signs – 04/02/2024 – Balance and Health

Transmitted by the bite of the female Aedes Aegypti infected with the virus, dengue was declared an emergency in ten Brazilian states and has already accumulated more than 2.2 million probable cases and 715 deaths in the first quarter of 2024 alone, according to data up to the 25th.

In the same period last year, 489,854 probable cases of dengue were recorded.

At the end of 2023, experts were already warning about an increase in the number of cases expected for 2024. “We have never had so many cases of dengue in the inter-epidemic period. El Niño and the increase in global temperature will impact the vector”, says Carlos Magno Fortaleza, president of the São Paulo Society of Infectious Diseases.

Today, the states with the highest number of cases of the disease are, respectively, the Federal District, Minas Gerais and Espírito Santo.

In total, there are four different serotypes of the disease: DENV-1, DENV-2, DENV-3 and DENV-4. All of them, however, cause similar symptoms, but to different degrees, and require treatments.

Below, see information about symptoms, warning signs and treatments against dengue.

Symptoms

Temperature above 38 °C, headaches, joint pain, pain behind the eyes, inflammation of the lymph nodes, itching and even red rashes on the skin are some of the classic symptoms of dengue when the condition is considered mild.

Some people may also develop an asymptomatic infection which, as the name suggests, has no symptoms.

In cases of severe dengue, it is common for symptoms to appear after the fever has disappeared and with some warning signs, signs that patients with mild cases may have complications from dengue. These include nausea, vomiting, bleeding in mucous membranes, severe abdominal pain and dizziness when standing up.

The risk group for the disease includes pregnant women, the elderly, children up to two years of age, diabetics, hypertensive patients, people with respiratory or cardiovascular problems and patients undergoing cancer treatment.

Testing for the disease

There are three methods for diagnosing dengue on the market: the NS1 Antigen, the PCR (Real-Time Polymerase Chain Reaction) and the IgM and IgG (immunoglobulins M and G).

NS1 is indicated for the beginning of the disease and identifies the concentration of antigens in the blood — obtained by finger prick or blood count — during the acute phase of dengue (up to the 5th day after infection).

The PCR test also uses blood collection from a symptomatic patient (or not), and detects the genetic material of the virus at an early stage of the disease. It also indicates the serotype causing the infection.

Serological (antibody) tests identify the levels of IgM and IgG antibodies —produced after initial contact with the dengue virus— and are carried out using a blood count or a drop of blood from a finger.

The IgM antibody appears soon after infection, between 5 and 7 days, and is only present during the infection phase, while the IgG remains in circulation for a longer period of time and may indicate that the person has been infected before.

The choice between patients who will be tested depends on the medical evaluation and the number of symptoms presented. In cases of signs similar to those of other diseases, such as Covid, the healthcare professional may request another type of exam and an analysis to conclude the diagnosis.

Medication and treatments

Although there is no specific medicine for dengue, for mild cases, dipyrone and paracetamol are usually indicated for home treatment of fever, common in cases of dengue. Rest and plenty of hydration with water and serums, which replenish the body’s mineral salts, are also recommended.

Professionals reinforce that self-medication is contraindicated. “It can be dangerous and mask important symptoms, complicating diagnosis and treatment”, explains Leonardo Weissmann, infectious disease doctor at the Emílio Ribas Institute of Infectious Diseases and professor at the University of Ribeirão Preto.

Corticosteroids, aspirin (such as AAS), and, mainly, non-steroidal anti-inflammatory drugs, such as ibuprofen and diclofenac, are also on the list of contraindications — the latter, in particular, increases the risk of bleeding in cases positive for dengue fever.

Reinfection

A person can be infected by the dengue virus a maximum of four times, once for each existing serotype, explains infectious disease specialist and professor at Unicamp (State University of Campinas), Raquel Stucchi. Reinfection, however, can only occur three months after the onset of symptoms.

“As they are not specific antibodies, they protect against other dengue serotypes that the person has not yet been exposed to. This is why reinfection is more difficult in the first three months”, explains the specialist.

The risk of severe dengue is more common when it is the second infection with the disease. According to Stucchi, a person may have been asymptomatic for a first case of dengue years ago and, with the second infection, progress to a severe stage.

The symptoms of reinfection are usually the same as the first infection, but may be more intense. “A more serious evolution can occur because you have an increased inflammatory response and the virus ends up multiplying more,” says Stucchi.

To avoid a second infection, the tip is to use repellent, including for people who are already infected with dengue. (here it talks about Stucchi repellent)

Repellents

With formulations made up of synthetic substances such as icaridin, DEET and IR3535, which repel insects, repellents can be medium or long lasting depending on what is written on the label.

Everyone can use repellents, according to experts. However, caution is needed with children, who often put their hands over their eyes and mouths. “The advice is not to apply it to the hands of young children. An adult should apply the repellent to their own hands and then spread it on the child’s body”, explains Evaldo Stanislau de Araújo, infectious disease specialist at Hospital das Clínicas de São Paulo.

For application, the recommendation is that it be done just like sunscreen: finally, about 15 minutes after applying products such as filter, moisturizer and perfume.

Experts still do not recommend using the product at night. “We can’t stay in contact with these products all day, all night. It’s good to remember other ways to protect ourselves”, says Gislaine Ricci Leonardi, PhD professor at the Faculty of Pharmaceutical Sciences at Unicamp.

The most sought after synthetic active ingredient in repellents is icaridin, of natural origin and with greater proven effectiveness, providing ten hours of protection. “Not only does it guarantee longer protection time, but it can also be used by pregnant women and children under 12 years of age”, says chemical engineer Norberto Luiz Afonso, president of Henlau Química.

There is also repellent for the home, which is recommended as long as it is registered with Anvisa (National Health Surveillance Agency). The device works when connected to a socket and, to find out how long it can be left on, you need to consult the leaflet.

Also according to Anvisa, insecticidal devices such as fumacê are effective against insects when applied during sunrise and sunset periods, when mosquitoes tend to be most active.

Vaccination

The Qdenga vaccine against dengue was approved by Anvisa last year for individuals aged 4 to 60 years, and incorporated by the SUS (Unified Health System) in December 2023.

The Ministry of Health, however, chose to make the vaccine available only to children aged 10 to 14, who are at greater risk of developing a serious condition.

Vaccination is carried out in two doses with an interval of three months between each dose. Among the expected side effects of the vaccine are pain or redness at the injection site, fever, headaches and muscle aches, general malaise and weakness. The health department recorded some cases of allergic reactions to the vaccine, but it was considered safe by experts.

The vaccine is not recommended for pregnant women, breastfeeding women, people allergic to any component of the vaccine or who have an immunological problem, such as those with HIV or undergoing treatment that affects the body’s defense cells, such as chemotherapy.

The vaccine, produced by the pharmaceutical company Takeda, was available on the private network and cost, on average, R$450 per dose, however, production was destined exclusively for the SUS at the beginning of March this year.