Chikungunya fever

Chikungunya fever is an infectious disease caused by the chikungunya virus (CHIKV), an alphavirus in the Togaviridae family, transmitted mainly by Aedes mosquitoes, especially Aedes aegypti and Aedes albopictus [1]. It is a major public health arboviral disease because it frequently causes symptomatic illness with fever and intense joint pain and may progress to prolonged rheumatic manifestations in a substantial proportion of infected individuals [2].

Etiologic agent and transmission

CHIKV circulates through transmission cycles that generally involve human infection followed by mosquito bites that sustain spread. In urban and peri-urban settings, transmission is primarily maintained by Aedes aegypti. In recent decades, Aedes albopictus has gained importance due to its wide geographic distribution and adaptability, including in more temperate environments [1]. The geographic expansion of these vectors, combined with human mobility, facilitates viral introduction into new areas and contributes to recurrent outbreaks [4].

From an evolutionary perspective, CHIKV is classified into lineages such as West African, East-Central-South-African, and Asian, which help explain dispersion patterns and epidemic waves [1].

Incubation and onset

After the bite of an infected mosquito, symptoms typically begin a few days later. In clinical practice, incubation often occurs around one week, with variability reported depending on context [3]. Onset is usually abrupt, with high fever and prominent joint pain [3,5].

Main clinical manifestations

The classic clinical presentation includes fever and polyarthralgia, often accompanied by myalgia, headache, fatigue, and rash [5]. Joint pain can be severe and disabling, frequently affecting peripheral joints and limiting daily activities from the first days of illness [1].

Although many cases improve over days to a few weeks, chikungunya differs from several other arboviral diseases because symptoms may persist, especially prolonged joint pain, stiffness, fatigue, and functional limitation [2,6]. This persistence is a key driver of disease burden, with direct impact on quality of life and work capacity [6,7].

Disease phases and chronicity

For didactic purposes, chikungunya can be described as having an acute phase (the first weeks) and, in some patients, a post-acute and chronic phase in which musculoskeletal symptoms persist for months [2]. The pathophysiology of pain and arthralgia involves viral tropism for musculoskeletal tissues, local and systemic inflammation, and, in some scenarios, mechanisms of neural sensitization and neuroinflammation that may contribute to chronic pain and, occasionally, neuropathic symptoms [6].

Severe disease and complications

Most cases are self-limited, but complications can occur. Neurological manifestations such as encephalitis and meningoencephalitis have been described, as well as severe forms in vulnerable populations, including extremes of age and people with comorbidities [7]. Although less frequent, these presentations are clinically important because of their potential severity and the need for surveillance [7].

Diagnosis in brief

Because symptoms can overlap with other arboviral infections such as dengue and Zika, laboratory confirmation is important in many settings. In the early phase, molecular tests that detect viral RNA, such as RT-PCR, tend to perform best during viremia, whereas serologic tests (IgM and IgG) become more useful a few days after symptom onset, when the humoral response becomes detectable [1,3]. This phase-oriented approach helps reduce false negatives and improves clinical and surveillance decision-making [1,3].

Epidemiological relevance

Since its introduction into the Americas in 2013, CHIKV has spread widely and continues to cause epidemics across multiple countries and territories, with millions of cases reported over the past decade [6]. During epidemic periods, chikungunya strains health services not only because of the volume of acute cases, but also due to prolonged demand related to persistent rheumatic symptoms and the need for follow-up and rehabilitation [2,6].

References

1. Bartholomeeusen, K., Daniel, M., LaBeaud, D. A., Gasque, P., Peeling, R. W., Stephenson, K. E., Ng, L. F. P., & Ariën, K. K. (2023). Chikungunya fever. Nature Reviews Disease Primers, 9(1), 17. https://doi.org/10.1038/s41572-023-00429-2

2. Chikungunya fever-review. (n.d.). [Author file].

3. Centers for Disease Control and Prevention. (2024, May 15). Clinical signs and symptoms of chikungunya virus disease. CDC.

4. Weaver, S. C., & Lecuit, M. (2015). Chikungunya virus and the global spread of a mosquito-borne disease. New England Journal of Medicine, 372(13), 1231–1239. https://doi.org/10.1056/NEJMra1406035

5. World Health Organization. (2025, April 14). Chikungunya (Fact sheet). WHO.

6. de Souza, W. M., Ribeiro, G. S., de Lima, S. T. S., de Jesus, R., Moreira, F. R. R., Whittaker, C., Sallum, M. A. M., Carrington, C. V. F., Sabino, E. C., Kitron, U., Faria, N. R., & Weaver, S. C. (2024). Chikungunya: A decade of burden in the Americas. The Lancet Regional Health – Americas, 30, 100673. https://doi.org/10.1016/j.lana.2023.100673

7. Pan American Health Organization. (n.d.). Chikungunya. PAHO.