Chikungunya Outbreak in Dourados: 42% of Brazil’s Deaths, Public Calamity Declared, Health Workers Trained, Civil Defense Mobilizes, 13th Fatality Reported in MS

Dourados, a city in the state of Mato Grosso do Sul, has become the epicenter of Brazil’s chikungunya outbreak, accounting for 42% of all chikungunya-related deaths in the country during 2026, according to data from the Folha de S.Paulo.

As of April 4, 2026, Mato Grosso do Sul had registered 4,281 probable cases of chikungunya, with 2,102 confirmed and 10 deaths reported, according to an epidemiological bulletin from the State Health Department cited by Outbreak News Today. The deaths were concentrated in the municipalities of Dourados, Bonito, Jardim, and Fátima do Sul.

Health professionals in Dourados have been undergoing training to administer the chikungunya vaccine as part of the public health response, reported by Midiamax. The vaccination campaign targets children and adolescents aged 10 to 14 years, 11 months and 29 days old — an age group identified as having the highest number of dengue-related hospitalizations in the state.

In addition to vaccination efforts, the Civil Defense has supported mosquito control operations in indigenous villages of Dourados, including cleaning campaigns to eliminate breeding sites of the Aedes aegypti mosquito, which transmits both chikungunya and dengue, according to Jornal de Brasília.

By April 13, 2026, the number of confirmed chikungunya-associated deaths in Mato Grosso do Sul had risen to 10, with fatalities recorded among older adults, infants, and residents of Indigenous communities, as reported by Beacon Bio. Among the deceased, five had pre-existing comorbidities.

On April 23, 2026, Campo Grande News reported the 13th chikungunya-related death in the state: an 87-year-old man from the municipality of Bonito. This brought the total number of chikungunya deaths in Mato Grosso do Sul to 13 by that date.

The Aedes aegypti mosquito, the primary vector for chikungunya transmission in Brazil, thrives in urban and semi-urban environments where standing water accumulates in containers such as tires, buckets, and flower pots. Public health officials continue to emphasize source reduction — eliminating stagnant water — as the most effective preventive measure against arboviral diseases like chikungunya and dengue.

Genomic surveillance efforts led by the National Network of Public Health Laboratories have generated 422 chikungunya virus genomes from 12 Brazilian states between 2021 and 2022, contributing to a better understanding of the virus’s dispersal dynamics. The East-Central-South-African lineage has shown evidence of expansion, with the Northeast region serving as a leading hub for viral spread to other parts of the country, according to research published in Nature.

Although the current outbreak in Mato Grosso do Sul is severe, health authorities note that no deaths from dengue have been reported or are under investigation in the state as of April 2026. The State Health Department has administered 223,322 doses of the dengue vaccine to the target population, with a total of 241,030 doses received from the Ministry of Health.

The chikungunya situation in Mato Grosso do Sul reflects a broader trend of increased arboviral transmission across the Region of the Americas, where changing weather patterns have favored mosquito proliferation beyond historical transmission zones. The World Health Organization has warned that populations in newly affected areas may lack awareness of clinical manifestations and immunological naivety, increasing the risk of severe outcomes.