Chikungunya is the most common of several, related alphaviruses that can cause arthritic symptoms. The name derives from kungunyala in the kiMakonde language of East Africa and literally means: 'bent over', referring to the stooped arthritic posture of chronic sufferers.

Since its discovery in 1952 in SE Tanzania, there have been several large-scale outbreaks of chikungunya in Africa, Asia and the Indian Ocean, with the Asian lineage first reaching the Americas in 2013. To date, over 100 countries have been affected.  While chikungunya is an ongoing, endemic risk in some countries (e.g. India), in terms of numbers, it tends to come to our attention more commonly as a disease of outbreaks (see below): The typical pattern of a chikungunya outbreak is to appear suddenly, spread rapidly through a population and then to burn itself out (particularly on islands), once herd immunity has been established.    

The degree of onward transmissibility, and severity of symptoms, varies depending on the particular genotype of virus associated with an outbreak: As a result of a single virus mutation (E1-A226V), one branch of the East-Central-South African (ECSA) lineage, now recognised as the Indian Ocean lineage (ECSA-IOL), has become much more transmissible via the invasive, cold-tolerant Aedes (Stegomyia) albopictus species, which is now the predominant mosquito vector in Europe, parts of Asia, the Americas, parts of West Africa and most Indian Ocean islands (including East and Central Highlands of Madagascar). 

Overall, the risk of chikungunya infection for travellers is lower than that of typhoid in South Asia, but currently higher than both yellow fever in at-risk parts of South America - or hepatitis A in Africa (R. Steffen, PATMF-Kairuki course, Aug 2025). 

A recent study in Minas Gerais State in Brazil revealed that we are probably underestimating by a half the true number of chikungunya cases occurring in Brazil, and overestimating the numbers of dengue cases (i.e. many chikungunya cases are mistaken clinically for dengue).  

There are currently several major regional outbreaks occurring:

→ South America & Cuba (new 'ECSA-American lineage', since 2023), mainly affecting Brazil (78,686 cases so far this year*), Bolivia (39,501 so far*), Argentina (10,724*), Suriname (7,484)* and French Guiane (415*) (*All data reported up to end of May 2026). Cuba reported 1,457 in January 2026 alone (no data since)... 

→ South Central Asia  (Indian Ocean lineage), affecting: Pakistan (17 cases so far in 2026 in Sindh), India (ongoing since 2008, with 165,971 in 2025 up to end November, particularly in Maharashtra, Karnataka and Gujarat), Sri Lanka & Maldives (outbreak 2024-25, now resolved).

→ SW Indian Ocean (new 'ECSA-2 lineage' since August 2024), affecting first Réunion (450,000 cases in 2025, now down to 100 active cases by end of March 2026), then: Mayotte (969 cases by 22 June 2025), Mauritius (resurgence of cases in 2026, with 2,816 reported to 11th May), Madagascar (29 cases so far in 2026, mainly in Mahajanga) and Seychelles... 

(Réunion previously suffered one of the worst outbreaks in 2005-06, in which an estimated 34% of the population was infected by a different lineage, thereafter known as the 'Indian Ocean lineage'. This left a large number of people with chronic arthritis. The predominant mosquito species in Réunion is Aedes (Stegomyia) albopictus, which may partly explain why the outbreaks took off so well). 66% of the population are now (2026) estimated to have immunity following the second (2024-25) outbreak, so reducing the likelihood of further outbreaks on the island.

→ Guangdong, China, (ECSA-2 lineage): New outbreak from June 2025 - now over.

→ SE Asia ('Asian-Pacific lineage', lower level), affecting: Cambodia, Timor Leste, Indonesia, Philippines and Thailand (outbreak in 2025, mainly in north: now largely over, with sporadic endemic cases) 

→ West Africa ('West African lineage', ongoing): Senegal (300 cases in 2024), Ivory Coast and low level endemic transmission across the Sahel.

Symptoms and treatment

The commonest presenting symptoms of chikungunya are: abrupt onset of fever and joint pain +/- muscle pain headache, nausea, fatigue and rash. A classic sign is tenosynovitis (not a feature of dengue or zika).

The joint pain can vary from mild to be very debilitating, and may last from a few days to many months or years, depending on the strain.  Overall, around 43% of people infected go on to the chronic phase with fatigue and/or joint pain symptoms persisting for months to years.   

There is no cure, only supportive treatment.  Non-steroidal anti-inflammatory drugs can be used to provide pain relief, but only if/once dengue has been excluded.

Unlike dengue, you can only be infected once with chikungunya: thereafter most people develop life-long immunity.  In about 1 in 1000 cases, however, the disease can be fatal. 

Prevention

An up-to-date awareness of local outbreaks in certain countries is important, for travellers and travel medicine practitioners alike: To check the latest situation on current or recent chikungunya outbreaks worldwide by region and country, please visit the ECDC web site here, the PAHO page here for the Americas, the MOH page here for India (by state), or the Boston BEACON outbreak page here.

Bite avoidance during the day with effective insect repellents (e.g. Mosiguard Extra® or DEET) is also a sensible precaution in all hotter parts of the world, not least for reducing the risk of dengue and zika infections, which are transmitted by the same Aedes (Stegomyia) mosquitos.  Chikungunya can also be transmitted to unborn babies during pregnancy.

The good news is that there are now two new chikungunya vaccines on the market:  

→ The first, Ixchiq, a single-dose, live attenuated vaccine, is now in stock. Ixchiq can now be given over the age of 12 years. Ixchiq has been shown to be extremely effective and long-lasting (99% by 1 month, falling to and levelling off at 97% after 2 years).  

However, a reanalysis of data from using Ixchiq to protect people in the recent Réunion outbreak showed that it can rarely lead to severe adverse reactions, akin to a chikungunya-like illness in older people with multiple health problems (n=17 between ages 62-89), reminiscent of the very rare serious side effects with Yellow Fever vaccine possible in older people receiving it for the first time).  A precautionary upper age limit of 65 was therefore temporarily applied in Europe from April 2025, but this restriction has since been lifted by the European Medicines Agency on 11th July 2025.  Current EU advice is to only prescribe Ixchiq for older travellers to places where there is a clear risk of infection, when an individual assessment of risks vs. benefits should naturally be made.

Ixchiq has been shown to be very effective against all circulating lineages of chikungunya virus, as well as providing good cross-protection against Mayaro virus, O'Nyong nyong virus and to a lesser extent (83%), Ross River virus.

→ A second, virus-like particle (non-live) vaccine, Vimkunya, is due to become available by 5th September 2025. Vimkunya can be safely given from the age of 12 years old and has no upper age limit.  It is also extremely effective with one dose (98% at one month), although fall-off is more likely and a 2-year study is under way to determine the longevity of protection and whether a booster dose would likely extend that significantly. 

On current evidence, Vimkunya would therefore appear to be the vaccine of choice for older people, those with multiple health problems, immunocompromised and/or pregnant women. 

Costs: Neither is cheap (!): Ixchiq: £149; Vimkunya: £154.  

© Jim Bond 10 April 2026