Chikungunya epidemic affects Brazil and increases number of cases and deaths

In the Americas, chikungunya cases nearly tripled, rising from 50,000 in 2022 to 135,000 in the first months of 2023

Brazil is facing an alarming chikungunya epidemic. The data reveal a worrying situation, with a geographic expansion and a significant growth in cases. According to the Ministry of Health, by the end of April, 86,900 cases of the disease had been reported, with an incidence rate of 40.7 cases per 100,000 inhabitants in the country. When compared to the same period in 2022, there was an increase of 40%. This year, there were 19 confirmed deaths. The highest incidences of the disease are in Tocantins, Minas Gerais, Espírito Santo and Mato Grosso do Sul.

On the global stage, the situation is no less alarming and the World Health Organization (WHO) has warned of an increase in cases of dengue, chikungunya and Zika around the world. The chikungunya virus is present in 115 countries. The Americas region is particularly affected in number of infections and deaths. Regionally, WHO assesses the risk as high due to the widespread presence of mosquito vectors, as well as the expansion outside historical areas of transmission, where the entire population, including risk groups and health professionals, may not be aware of the clinical manifestations of the disease. disease, including severe conditions. According to WHO technical lead for Zika and chikungunya and co-leader of the Global Arbovirus Initiative, Diana Rojas Alvarez, cases of chikungunya in the Americas have nearly tripled, from 50,000 in 2022 to 135,000 in the first few months of this year. The country most affected is Paraguay, which recorded its worst epidemic in history with 138,730 cases. Argentina and Uruguay also reported local transmission for the first time in 2023, and Bolivia reports high levels of chikungunya transmission (1,150 cases).

The epidemiologist and professor of Epidemiology and Biostatistics at the Faculty of Medicine São Leopoldo Mandic in Campinas, Dr. André Ribas Freitas, explains that the epidemiological situation of arboviruses in general has been quite unfavorable and annually we have witnessed epidemics. According to him, with the Covid pandemic there was a decrease in the number of cases due to people being in isolation and also, in some way, greater care with the domestic space, contributed to the control of the disease. “However, now with the return to routine activities, with the usual problems in the disposal of solid waste and population density in large cities, all of this combined with climate change, are factors that favor the increase in the number of cases and the area of ​​occurrence of chikungunya”, he adds.

Asked whether there are genetic variations of the virus currently circulating in Brazil, which may be associated with an increase in the number of cases and deaths, the researcher points out that there is no evidence of a change in the genetic profile. “It is a very aggressive virus with a relatively high lethality rate when compared to other similar diseases. It happens that, many times, we are not able to faithfully identify the number of deaths, so we have the impression that in a given year there are more deaths, but this occurs due to a more detailed investigation”, clarifies the researcher.

Challenges

The rapid spread and worsening of the disease have created challenges for public health authorities and health professionals. According with the doctor. Freitas, regarding the diagnosis, the great challenge is the possibility of clinically being very confused with dengue and other arboviruses. Another issue mentioned is that clinical diagnostic exams are often lacking. The epidemiologist also cites the difficulty in relation to the molecular biology test, which is unavailable in several regions of the country, making it difficult to make a more accurate diagnosis in the early stages of the disease.

“Another complexity of chikungunya is the fact that we don’t know exactly what are the therapeutic possibilities that could prevent death. There is no antiviral treatment available. Treatment is currently focused on clinical support for possible circulatory, respiratory or neurological complications”, he emphasizes. Although the most common clinical complications associated with chikungunya are the acute clinical picture with severe joint pain, including disabling pain, which can lead to chronicity, the most serious complications are those that affect the cardiovascular system, the respiratory system and the central nervous system. . Chikungunya can cause hemodynamic instability due to direct heart damage from the virus or systemic inflammation, neurological changes ranging from neuritis, myelitis to encephalitis, meningitis, etc.

The professor admits that the lethality rate is another issue that is quite difficult to establish, since not all cases are properly diagnosed, as well as those that evolve to death are often not recognized. “The clinical overlap and the difficulty of differential diagnosis between a patient with chikungunya and dengue, often causes this patient to be mistakenly identified with dengue, a more common arbovirus. That is, the difficulty of diagnosis masks the identification of the size of the problem of death associated with chikungunya”, he points out.

Efforts to contain the spread of the disease are being stepped up. Awareness campaigns and to educate the population about preventive measures, such as eliminating possible mosquito breeding sites and the use of repellents, were launched by the Ministry of Health, which also made available a regularly updated panel with the main data on arboviruses and the epidemiological situation in the country. Follow here.

Health authorities have been working closely with experts and research institutions to improve knowledge about the disease and develop more effective strategies. In Brazil, there are several initiatives to improve the understanding of the risk factors associated with the worsening of the patient with chikungunya. One of these is the Chikungunya Clinical and Applied Research Network (Replick). The Doctor. Freitas says that this consortium has discussed several aspects related to the protocols and his expectation is that in the coming years there may be some elucidation about the factors associated with the aggravation and also about the treatment to be instituted to avoid the complications of the disease.

Experts warn of the need for investment in scientific research for the development of vaccines and more effective treatments against the disease and early diagnosis. Collaboration between affected countries, WHO and other international institutions is essential to address this global threat. It is important that all sectors of society unite to face the epidemic. Collaboration between federal, state and municipal governments is also essential. Faced with the increase in cases in Brazil and in the world, governments and communities must intensify their efforts to prevent and combat the disease. People should be actively involved in eliminating potential mosquito breeding sites in their homes and community areas. Prevention, awareness and the adoption of effective control measures are the main weapons to combat the spread of the virus.

Lastly, Dr. Freitas recalls that chikungunya affects all age groups without distinction, however, carriers of pre-existing diseases (mainly diabetes, hypertension, cardiovascular disease), children under 5 years of age and the elderly are more susceptible to severe clinical forms. This group also has a higher fatality rate. Although death is more frequent among patients with comorbidities, people without previous illnesses and young adults, who are not part of the risk group, are also at risk of death. “Although it is a disease that is little known in Brazil, it is necessary to recognize that it is potentially serious and the aggravation is not exclusively associated with joint pain, it can lead to serious forms in the circulatory system, in the central nervous system, etc. Therefore, it is important to identify early the occurrence of chikungunya in their localities, so that clinical support can be carried out and control actions taken, according to the need”, he emphasizes. Facing a chikungunya epidemic is a complex challenge, but with quick and effective actions, it is possible to reduce the number of cases and deaths associated with the disease.

Epidemiological overview of the virus in Brazil

A study entitled “Spatiotemporal dynamics and recurrence of chikungunya virus in Brazil: an epidemiological study”, published in the scientific journal The Lancet Microbe, on April 6, details the spread of the chikungunya virus since its introduction in Brazil. The research, which includes the participation of the University of São Paulo (USP), analyzed 253,545 cases confirmed in the laboratory between 2013 and 2022. According to the data, the disease was heterogeneously distributed across the country, with the most affected cities showing some protection against new outbreaks, while municipalities less exposed to previous waves remained more susceptible. Ceará was the most affected state, with 77,418 cases during the three biggest epidemic waves, which occurred in 2016, 2017 and 2022.

For the study, genomic sequencing data, vector information and aggregated clinical data of cases were used. Subsequently, the space-time dynamics of the disease was evaluated through time series, mapping, age and sex distribution, lethality and genetic analysis, etc. Between March 2013 and June 2022, 253,545 laboratory-confirmed cases were reported in 3,316 (59.5%) of the 5,570 municipalities, distributed mainly in seven epidemic waves from 2016 to 2022.

about the disease

Chikungunya is caused by the CHIKV virus, transmitted mainly by the Aedes aegypti mosquito, the same vector responsible for the spread of dengue and zika. The disease was first identified in Brazil in 2014 and has since spread rapidly, affecting millions of people across the country. Symptoms include fever (which can be high), severe joint pain, headache, rash, and fatigue. Symptoms can be debilitating and last for weeks, significantly affecting people’s ability to carry out their daily activities. Most patients recover completely, however, a significant percentage develop serious complications, which can lead to death.