Paraguay's Chikungunya Outbreak, 2022–2023: 81,037 Cases and 52 Deaths

The virus

Chikungunya virus (CHIKV) first spread locally in the Americas in December 2013, then widely across the region. It is carried mainly by Aedes aegypti and Aedes albopictus mosquitoes. Most infected people (72%–97%) fall ill, usually with fever and often severe joint pain that can last months or years. Rare complications affect the nerves, heart or kidneys.

Paraguay's outbreaks

• 2015–2016: after its first locally acquired case in 2015, Paraguay had 5,221 cases, mostly in the capital, Asunción, and neighboring Central Department.
• 2018: 1,239 cases in north-central Amambay Department.
• 2022–2023: cases rose again from the first week of October 2022. This report covers the outbreak up to March 11, 2023.

The 2022–2023 outbreak

The Ministry of Health recorded 81,037 suspected, probable or confirmed cases from October 1, 2022, to March 11, 2023, 75,911 (94%) of them in 2023.

• Where: Central Department (49,070, 61%) and Asunción (16,094, 20%). The national rate was 1,073 per 100,000 people, and 3,088 per 100,000 in Asunción. After epidemiologic week 6, weekly cases there dipped slightly while more and more came from outlying regions, including along the Brazil and Argentina borders.
• Who: among 47,116 probable or confirmed cases, 58% were female; the median age was 36 (from newborns to 103). There were 4,604 hospitalizations (10%) and 52 deaths attributed to the virus.
• Newborns (up to 29 days old): 208 cases, 140 hospitalizations and eight deaths — the highest case fatality rate of any age group, 3.8%. In the fatal cases, symptom timing pointed to infection during birth in 75% and by mosquito in 25%.
• Adults 60 and older: 10,617 cases and 1,878 hospitalizations — 41% of all — and 32 deaths. Of those who died, 23 (72%) had cardiovascular disease, 13 (41%) diabetes, and 20 (63%) two or more conditions. Fatality was highest at 80 and older: 0.6% (11 of 1,719).

Chikungunya in Paraguay by age group, October 2022–March 2023. CDC, MMWR.

Lessons

CHIKV can cause explosive outbreaks and heavy illness at every age; older adults, people with other conditions and infants face the most severe disease and death.

Prevent bites:

• wear long sleeves and long pants;
• use insect repellent;
• screen windows and doors;
• cover cribs, strollers and beds with netting;
• remove breeding sites around the home by emptying, scrubbing or covering anything that holds water;
• support community mosquito surveillance and control.

People who may be infected should avoid bites to protect others. These steps also lower the risk of dengue and Zika, which often circulate at the same time — dengue was circulating in Paraguay.

Care: there is no antiviral treatment, so getting guidance on diagnosis and management out quickly is crucial. Newborns possibly infected during birth should be watched in hospital for their first week, because they can worsen fast. Hospitals should protect staff and patients with bed nets and repellent for chikungunya patients and by clearing breeding sites from their grounds.

Spread: people are the main reservoir during epidemics and can carry the virus to new places — cases have turned up in travelers returning from Paraguay to several countries, and a mosquito bite at the destination can start local spread. In 2022–2023, chikungunya rose across the Americas and reached places outside its usual range, such as Uruguay and parts of Argentina. Stronger surveillance and preparedness matter, and several vaccines in late-stage development could reduce cases and deaths in future outbreaks.

Sources

Based on "Notes from the Field: Chikungunya Outbreak — Paraguay, 2022–2023," by Martha Torales and colleagues of Paraguay's Ministry of Public Health and Social Welfare and CDC, Morbidity and Mortality Weekly Report, CDC; a work of the United States government in the public domain.