Insect-spread disease chikungunya is on the rise – and has now made its way from Africa to the USA. But just how dangerous is this ‘new’ disease?
Chikungunya, a ‘new’ form of break-bone fever, was first described in East Africa in the 1950s but it is now spreading globally. In July, the first locally-acquired case was reported in Florida. The disease is now known to occur in nearly 40 countries. But from where did it appear? And how serious a threat is it to travellers?
Chikungunya (pronounced chik-un-GUHN-ya) is a good example of an ‘emerging’ infection. It was first recognised and described in 1952 in Tanzania; its name derives from a word in the Kimakonde language that describes the distorted posture sufferers adopt because of severe joint pain. However, the disease was largely ignored for decades.
This kind of disregard can happen, worldwide, for a multitude of reasons. For instance, sometimes a disease is locally politically unacceptable. When I worked in Indonesia, colleagues assured me repeatedly that Japanese encephalitis wasn’t a public-health problem in Indonesia – despite the fact that it was an issue in the countries all around; because Indonesia is a Muslim state, a disease that was transmitted from pigs to people just wasn’t allowed to exist. Statistics for HIV/ Aids may also be inaccurate for similar political reasons.
In many low-income countries, clinicians may be too busy simply caring for enormous numbers of ill people that they have no time for reporting causes of illness. Then there are the difficult diseases, such as polio and cholera, which can simmer in a community making only a tiny proportion of infected people ill; health surveillance can miss such infections – until there is a massive outbreak.
In the case of chikungunya, it was seen as an unpleasant but rarely serious illness restricted to a limited area of Africa. The joint pain often settled in a few days and nearly all patients recovered completely. It was recognised as an infection spread by mosquitoes, but in Tanzania malaria was a much bigger public-health challenge. And, anyway, avoiding malaria through bite prevention might help control chikungunya.
So chikungunya wasn’t deemed a big issue. But then it started to spread. In 1999-2000 there was a large outbreak in the Democratic Republic of the Congo. In 2005, cases appeared in the Indian Ocean islands. From there, travellers brought it home as an unwanted souvenir. That is when we started hearing about it.
According to the World Health Organisation, India, Indonesia, Thailand, Maldives and Myanmar have recorded over 1.9 million cases since 2005. Since 2007, a few locally-acquired cases have been documented most years in Italy.
Around 8,000 cases have been seen in the Caribbean since spring this year. The first case contracted in Florida was reported in July 2014. Now chikungunya is known to occur in nearly 40 countries across Asia, Africa, Europe and the Americas.
How it strikes
Chikungunya is generally spread by day-biting Aedes mosquitoes, which are most likely to attack those who sleep out during the day: babies, infants and the already ill or infirm are most at risk. Two to 12 days after an infective bite, there is an abrupt onset of high fever with debilitatingly bad joint pain. There can also be headache, fatigue, nausea and a rash, although often the symptoms are mild.
Complications are uncommon but occasionally, in the frail, it can contribute to death. Generally though, recovery is speedy and complete. The pattern with chikungunya is common to other ‘new’ diseases when they first hit the headlines. Firstly doctors notice and report the severest cases and there is a tendency for journalists to imply that we’re all going to die. Then, as more information and experience piles up, it often transpires that people in reasonable health are unlikely to be badly hit.
Even so, this isn’t an experience that will enhance your trip; avoidance is a great idea.
How to avoid it
The Aedes mosquitoes that spread chikungunya are stripy-legged and hungriest in the early mornings and the afternoons. Cover-all clothes and a good insect repellent will protect you; the best contain DEET, IR3535 or icaridin. If you’re planning to take an after-lunch siesta, sleep under a mosquito net or retire to a screened room.
Aedes breed in – and tend to stay close to – clean water, including collections of rainwater caught in the bracts of big tropical plants in lush hotel gardens. Aedes also hang about in beach bars and restaurants if there are places where rainwater is allowed to accumulate or drinking water is stored uncovered.
Diagnosis & treatment
Chikungunya is a viral infection and there’s no specific treatment. Even so, if you develop a temperature over 38.5°C it’s sensible to go to a clinic to arrange a diagnosis. In the tropics there are a range of infections that cause fever and aches, and some are eminently treatable.
Taking regular paracetamol will help relieve the aches; it would probably be best not to take ibuprofen as this can complicate and even worsen the situation if you have the rather similar dengue fever. Be reassured, though, that these diseases are rarely dangerous. Generally they are short-lived and there are unlikely to be any long-term consequences.
What else could it be?
Many diseases announce themselves with fever, but the cause is probably trivial if your temperature is below 38.5°C. Tonsillitis is a common cause of high fever and generalised aches and pains.
Dengue is the disease most likely to be confused with chikungunya. Dengue is rare in Africa but there are often outbreaks in South-East Asia and tropical Latin America. Dengue also starts with an abrupt arrival of fever, headache with pain behind the eyes, and severe joint aches and muscle pain; this starts three to 15 days after the infective bite. Most cases settle in two weeks but fatigue lasts longer.
There is a dangerous form of dengue that may be heralded by bleeding gums, nosebleeds or blood in the urine; this can be serious and needs medical care. Main image: Aedes mosquito (Shutterstock)