In 2017, 855 Brazilian cities were at risk or on alert for outbreaks of dengue , zika and chikungunya , according to data from the Ministry of Health. showing reduction, but diseases still circulate in the country.
Although until April 2018, the Ministry of Health reported a reduction in cases of dengue, zika and chikungunya, compared to the same period in 2017 (a decrease of 20%, 65% and 70% of cases respectively), published data in December 2018 show that 1881 are still on alert.
The 3 viruses, DENV, ZIKV and CHIKV are transmitted by Aedes, making up a public health problem.
Although there are some specific symptoms in each infection, the conditions can be quite similar and confuse the diagnosis, especially in the first manifestations.
Learn more about the virus of each disease and how to prevent it:
- 1 Or Aedes mosquito
- 2 Dengue virus
- 3 Vírus da chikungunya
- 4 Zika virus
- 5 How to prevent
In relation to the transmission of dengue, zika and chikungunya, there are 2 species of Aedes mosquitoes that can be vectors: Aedes aegypti and Aedes albopictus.
The Aedes aegypti mosquito has some anatomical characteristics that enable its identification. Its size is smaller compared to the common insect and its body has white stripes on the trunk, head and legs. When it flies, it makes almost no noise, which makes it more difficult to perceive its approach and circulation.
Males do not depend on blood and, therefore, eat only fruit. Therefore, it is the females that bite humans and transmit diseases.
Also, not all Aedes have dengue, zika or chikungunya viruses. Therefore, it is necessary for the insect to bite someone infected and contract the virus to start transmission.
After it is infected, there is no way to eliminate the virus, making it a vector for your entire life – which can last for about 30 days. When laying eggs, at least part of the new mosquitoes will be born infected, becoming vectors.
Each female of the Aedes can lay about 200 eggs, which are deposited on the surface of the standing water.
When this water comes into contact with the eggs, there is a very fast hatching, starting the period of development of the larva. It takes between 7 and 9 days for a new mosquito to circulate.
The other possible species to transmit diseases is Aedes albopictus , considered a secondary vector of dengue, with characteristics similar to those of Aedes aegypti , but with a slightly larger size, darker color and only a white stripe on its body.
The life cycle of both is quite similar, however, despite circulating in Brazil, there are no records of mosquitoes of the species A. albopictus disease vectors.
The dengue virus is well known in the history of societies. Originating in Africa, more specifically in Egypt, it was in the beginning of the 19th century that the first epidemic of the disease occurred on the American continent, in addition to outbreaks in the Caribbean, the United States, Colombia and Venezuela.
In Brazil, there are records of dengue at the end of the 19th century, more specifically in Rio de Janeiro and Curitiba.
The disease tends to be very common in tropical and subtropical countries, due to the climate. Up to four types can be found in Brazil: DENV-1, DENV-2, DENV-3 and DENV-4, caused by the same virus that presents small changes in your body.
After being infected, the patient is immune to the type of dengue that affected him, but due to the small difference of each virus, it is possible that he is infected more than once (that is, there can be up to 4 dengue infections).
The symptoms are the same, regardless of the virus, however, with each occurrence, the condition tends to worsen, allowing complications, such as hemorrhagic dengue or increasing the risks to the patient’s life.
Symptoms of dengue
The main symptoms of dengue are high fever , usually between 39 ° C and 40 ° C, which starts suddenly, pain in the muscles (myalgia), articular (arthralgia), head, behind the eyes and sometimes red spots on the skin. skin that can itch.
Other symptoms that can manifest themselves and, in general, are warning signs, include:
- Nausea and vomiting;
- Pain in the abdominal region;
- Liver enlargement;
- Extreme tiredness.
The diagnosis considers, in addition to the symptoms, the presence of the patient in risk areas or possible outbreaks of the disease, which can be confirmed through blood tests that identify specific antibodies in the sample collected.
There is no specific treatment for dengue cases. Doctors often prescribe medications to relieve symptoms, such as fever and muscle pain.
It is important to note that acetylsalicylic acid should not be used in cases of suspected or confirmed dengue.
Therefore, it is essential to see a doctor at the first symptoms, because only he will be able to identify the disease and advise the best form of treatment.
Along with medication, it is important for the patient to rest and intensify hydration.
Aedes mosquitoes can also be vectors of the CHIKV virus, originally from Africa and responsible for chikungunya fever.
It was in 1952 that the microorganism was isolated in Tanzania, and the first emergency cases were observed in Southeast Asia and India.
In 2004, in Kenya, there was the second major case of chikungunya, in which warning signs were issued about the disease, but it was only in 2013 that the virus reached the Americas and infected thousands of people.
A year later, in 2014, Brazil reported the first cases of the disease, raising concerns about epidemics, especially in the states of Amapá and Bahia.
In 2016, chikungunya fever had an increase of 620% in cases compared to 2015. In total numbers, it means that in one year the diagnoses rose from 36 thousand to 263 thousand.
The incubation time of the virus lasts approximately 10 days, this means that, during this period, there are no manifestations or signs of the infection.
Chikungunya has symptoms that, in some cases, are quite similar to those of dengue, but are generally milder or milder. The risks to the patient’s life are also less, making deaths from CHIKV uncommon.
As with dengue, there may be pain in the joints of the feet, hands, fingers, ankles and wrists (arthralgia), which is the most common symptom and usually quite intense enough to limit the patient’s movements for months or years.
- Muscle aches;
- Reddish patches on the skin that itch a lot;
- High fever that starts quickly.
But it is important to know that, on average, 30% of infected people have no symptoms.
Although not very common, it is possible that the virus is transmitted through childbirth, being called vertical transmission. When this happens, severe cases of neonatal infection can arise, with severe skin involvement, fever and pain. Even children who are born without visible signs of the infection, must be carefully monitored due to the possibility of late manifestation.
Elderly people over 65 years old, under 2 years old, people with previous joint injuries, chronic or autoimmune diseases (such as diabetes or lupus , respectively) should be aware if chikungunya is suspected, as there are greater risks of complications arising.
According to information from the Ministry of Health, health professionals should consider CHIKV infection in patients who have had recent symmetrical polyarthritis.
The diagnosis of the disease is generally clinical, in which the very characteristic symptoms are suggestive of the disease, especially in seasons or regions with prevalence of the Aedes mosquito.
However, there are specific tests that can affirm chikungunya, through the presence of specific antibodies in the blood for CHIKV or isolation of the virus by culture technique, for example.
The treatment, in most cases, consists of rest and alleviation of malaise, using antipyretics ( paracetamol ) and anti-inflammatories. Hydration and rest are essential for the body to recover in the best possible way. The use of acetylsalicylic acid (ASA) is also discouraged, as it increases the risk of bleeding.
Patients with complications or associated diseases must be assessed individually by the health professional, who will consider the therapeutic needs of each case.
The Zika virus, also transmitted by the Aedes aegypti mosquito , was first identified in 1947 in Uganda, but it only arrived in Brazil in 2015, reaching Rio Grande do Norte and Bahia.
Called ZIKV, the microorganism has been shown to be less aggressive compared to the dengue virus, mainly because it does not cause such severe and long-lasting symptoms.
On the other hand, when it reaches pregnant women, the infection can cause complications to the fetus due to the risks of microcephaly, a neurological condition in which the baby’s head is smaller in size than is appropriate for the age.
Congenital malformation is associated with mental problems, learning difficulties and other changes.
But it is worth mentioning that not every pregnant woman infected with Zika will give birth to a baby with microcephaly. On average, between 6% and 12% of children are affected by the neurological condition.
In relation to dengue and chikungunya, Zika has even milder manifestations, with about 80% of patients having no symptoms.
However, when they appear, mild or moderate joint pain (predominantly in the extremities of the body) may appear, sometimes accompanied by swelling in the joints, in addition to irritation or redness in the eyes.
Red spots usually appear accompanied by severe itching. Symptoms usually remain between 3 and 7 days.
In complicated cases, neurological impairment and autoimmune changes can occur, capable of triggering Guillain-Barré Syndrome.
The diagnosis is made based on the symptoms and circulation of the virus (outbreaks or endemics). Therefore, it is necessary to investigate whether the patient lives in risky regions or has traveled to endemic locations.
Laboratory tests may also be ordered to confirm Zika infection. The tests are performed with blood samples from the patient, seeking to identify the virus or specific antibodies.
The treatment for Zika is based on the alleviation of symptoms and recovery of the organism. Therefore, in symptomatic cases, the use of paracetamol or dipyrone may be necessary , aiming at the control and reduction of pain and fever, in addition to antihistamines to relieve itching and skin irritation.
In Zika, the use of acetyl salicylic acid (ASA) or other anti-inflammatory drugs is also not recommended due to the risk of bleeding.
During recovery, the patient must prioritize hydration and rest.
Why do you have to worry about microcephaly?
Microcephaly is not a new condition in medicine and its causes are quite diverse, such as viral diseases (rubella, herpes and, of course, zika), high blood pressure during pregnancy and genetic factors.
In cases of microcephaly, the child should be referred for follow-up and stimulation as soon as possible. There is no specific treatment for the condition, but assistance and support for the newborn helps to improve development throughout childhood.
It is important to note that children, immediately after being diagnosed with microcephaly, are included in the Early Stimulation Program, of the Unified Health System (SUS), allowing the physical, motor, neurological, behavioral, cognitive, social and affective aspects to be worked on, giving greater autonomy to the patient.
How to prevent
The DENV, CHIKV and ZIKV viruses infect the human body predominantly by the bite of the Aedes mosquito. In dengue cases, for example, there are also reports of vertical transmission (from infected mother to baby during delivery) and blood transfusion.
Therefore, preventive measures are mainly focused on eliminating outbreaks of Aedes, reducing the circulation of the mosquito. It is also recommended to adopt protective measures, such as the use of repellents and clothes that cover the entire skin, reducing the possibility of bites.
Eliminating or reducing the circulation of the Aedes vector helps to fight dengue, chikungunya and zika. Check out the measures:
- Put sand on dishes and plant pots so that rainwater does not accumulate;
- Try to keep plastic bottles, glasses and pots upside down, especially when they are outside;
- Also the water boxes well;
- Clean the house gutters and avoid the accumulation of rainwater;
- Old tires should not be stored outdoors;
- Use window screens and mosquito nets at night;
- Prefer long clothes that cover the skin;
- Use repellents on exposed skin areas;
- Notify the city of vacant lots or houses that do not maintain preventive care.
Repellents: how to use correctly
With the beginning of the dengue, zika and chikungunya epidemics, the use of repellents became quite common. The product can be combined in the protection against Aedes and does not represent risks, as long as it is approved by the National Health Surveillance Agency (Anvisa), according to information from the agency itself.
When choosing the product, two things are essential: be aware of the label and consider the age of who will use it.
According to the World Health Organization, products based on DEET, IR 3535 and Icaridina, a repellent substance, are safe and able to ward off mosquitoes.
The indications are:
- DEEDT : recommended from 2 years of age, has protection of about 2 hours;
- IR 3535 : indicated from 6 months of age, with protection time of approximately 4 hours;
- Icaridine : recommended from 2 years of age, reaching up to 10 hours of protection.
It is also recommended that children from 2 to 12 years of age should use DEET-based repellents with maximum concentrations of 10%. Older than 12 years may prefer higher concentrations.
It is important to make the correct application of the product, protecting all the extension of the skin and over the clothes as well. On the label of products certified by ANVISA, there is always the method of use and the frequency of application, which must be respected for the best effectiveness and protection.
Among the options available on the market are:
- Off Family;
- Repelex ;
- Children’s Exhibition ;
- Off Kids.
In order to protect children under 6 months of age, it is advisable to stay away from any type of repellent, as the toxicity of the product can be harmful to health, except under the guidance of the pediatrician. It is essential to look for alternative methods, such as the use of mosquito nets, to reduce exposure to mosquitoes and to use more closed clothes (which keep the skin protected).
At home it may be interesting to use electric or environmental repellents, which help in the dispersion of insects in general. In addition, the use of screens on doors and windows can assist in protection, preventing Aedes from entering homes.
Dengue, zika and chikungunya are diseases transmitted predominantly by the bite of the Aedes mosquito.
When they bite an infected person, the mosquito becomes infected and becomes a vector, spreading the disease through the bites. In addition, when laying eggs, Aedes transmits the virus to new mosquitoes, increasing the circulation of vectors.
To prevent dengue, zika and chikungunya, it is necessary to adopt measures to fight the mosquito, eliminating outbreaks and paying attention to personal care.
For more tips on how to prevent yourself, keep an eye on the Healthy Minute!