What is Chikungunya Fever?
Chikungunya virus (CHIKV) is a type of virus carried and spread by Aedes mosquitoes. This virus belongs to the Togaviridae family. CHIKV is known for causing a disease known as Chikungunya fever, which begins with a high fever, rash, and joint pain. After the initial illness, sufferers may continue to experience painful joints for months or even years.
Historically, CHIKV was primarily found in Africa and Asia. The first time it was identified was in Tanzania in 1952. The name “Chikungunya” comes from a local Tanzanian phrase that translates to “that which bends up,” referring to the effect of the joint pain caused by the disease. The most severe outbreak occurred on Reunion Island in 2005-2006 where nearly 35% of the population was infected with the virus.
Since 2005, Chikungunya fever has spread primarily to tropical and subtropical regions and eventually reached the Americas in 2013 via St. Martin, a Caribbean island. Today, CHIKV is found globally and poses a significant concern for public health worldwide.
What Causes Chikungunya Fever?
The main carriers for Chikungunya fever, a viral disease, are mosquitoes known as Aedes aegypti and Ae. albopictus, also referred to as the Asian Tiger mosquito. These mosquitoes have certain traits that make them especially effective in spreading this disease.
One of these characteristics is ‘invasiveness’, which means they prefer human blood and can thrive outside their natural habitats. Another is their ‘vector competence’, which refers to the mosquitoes’ ability to pick up the virus when they bite an infected person and transfer it to others through their saliva when they bite again.
Lastly, there’s ‘vector capacity’. This relates to the potential for an outbreak and depends on a combination of factors. These include the number of mosquitoes compared to the number of people, the likelihood of a mosquito biting a person in a day, how long a mosquito lives, and how long it takes for the virus to develop in the mosquito so it can be passed on – all these factors determine how easily a mosquito can infect a person.
The Aedes aegypti mosquito has been in the U.S. for over 300 years, and the Ae. albopictus mosquito has been present since 1985. These mosquitoes have uniquely different features that make the global spread of Chikungunya possible. During an outbreak in the Indian Ocean between 2005-06, it was found that the virus had adapted to infect the Ae. albopictus mosquito, which helped its spread.
In general, the threat of these mosquitoes to public health comes from their preference for human blood and their association with humans, along with the ability of both humans and mosquitoes to travel, therefore spreading the disease further.
Risk Factors and Frequency for Chikungunya Fever
The CHIKV virus, first found in Tanzania in 1952, has since spread to many parts of the world, including the Americas in 2013 and Florida in July 2014. It’s affected many areas in the Caribbean, Central, and South America. Despite being native to parts of West Africa, the virus’s spread has been helped by human movement and mosquitoes travelling around the world. People carrying the virus can bring it into new areas, where local mosquitoes can then spread it. Ships and planes transporting mosquito larvae and eggs also help bring these insects into new, welcoming environments. The virus is mainly spread through mosquito bites but can also be passed from mother to baby during pregnancy, or through blood products, as seen during outbreaks in Reunion Island.
The Aedes aegypti and Aedes albopictus mosquitoes, known for spreading the CHIKV virus, are also responsible for spreading other diseases like Dengue and Zika. People can have more than one of these diseases at a time. Because the symptoms are similar and the areas affected by these diseases are almost the same, it can be challenging to tell which disease a person has.
Signs and Symptoms of Chikungunya Fever
Chikungunya fever is a condition that often begins with a high fever and muscle pain after the virus incubates in your body for about 3 to 7 days. This fever phase lasts for around 3 to 5 days. Subsequently, people may experience pain in their joints, especially in the hands, and this typically begins 2 to 5 days after the fever starts. The joint pain tends to affect the ends of the limbs more than the proximal joints. It’s accompanied by a significant amount of pain that lingers for about one to three weeks.
Another symptom associated with Chikungunya fever is a widespread rash that usually appears on the limbs first, around 3 days after the initial fever symptoms. In some instances, people may also develop small, raised skin lesions or lesions that affect the skin and mucous membranes.
Additional symptoms may include:
- Abdominal pain
- Diarrhea
- Vomiting
- Swelling of lymph nodes
Although Chikungunya is typically not associated with affecting the nervous system, there have been cases of newborns developing inflammation of the brain when infected through mother-to-child transmission. Some people may also experience red eyes, conjunctivitis, and inflammation of the front part of the eye. Furthermore, the disease can cause recurrent inflammation of the retina, symptoms in the eyes at birth, blood poisoning, shock, and kidney problems.
Testing for Chikungunya Fever
Chikungunya fever is often diagnosed by symptoms such as fever and joint pain, especially if someone has recently travelled to an area where the disease is common. However, it’s tricky to differentiate between Chikungunya and another condition called Dengue fever, since they often occur in the same areas and share some symptoms. Chikungunya is more likely to cause high fever, serious joint pain, a rash, and a lower-than-normal number of white blood cells under a microscope. Dengue, on the other hand, tends to decrease the number of certain blood cells, cause bleeding, shock and can even lead to death. Due to this, the World Health Organization advises doctors to treat all suspected cases as Dengue until proven otherwise.
The diagnosis of Chikungunya fever can be confirmed by testing for the presence of the virus in the body. There are two main methods: RT-PCR and serology. The RT-PCR test looks for the virus’s genetic material and is most effective in the early stages of the disease, specifically within the first five days. Serology tests, which consist of techniques like ELISA or IFA, detect antibodies specifically made by the immune system to fight off the Chikungunya virus. These antibodies can be of two types: IgM, which appear five days to several weeks after infection, and IgG, which can be found anytime from two weeks to several years after infection. Both the Centers for Disease Control and Prevention and the World Health Organization recommend these tests for patients showing symptoms suggestive of Chikungunya, Dengue, or Zika virus infection.
It’s important to note that Chikungunya fever is a disease that doctors are required to report to health authorities when they come across it.
Treatment Options for Chikungunya Fever
If you’re suffering from Chikungunya fever, the main concern is to relieve your symptoms. This typically means drinking plenty of fluids, resting, and using medication like acetaminophen to manage pain and fever. Aspirin and other similar drugs, known as nonsteroidal anti-inflammatory drugs (NSAIDs), are usually avoided in the initial 48 hours since they could potentially interfere with the function of your blood cells, particularly if you might be co-infected with Dengue virus (DENV). Some research suggests that low-dose corticosteroid drugs, used for the first two months after the onset of illness, can be effective. If you’re experiencing eye problems, such as inflammation of the front or back of the eye (uveitis), these might be treated with topical steroids and other specific eye drops.
If Chikungunya fever persists and causes chronic symptoms such as recurring joint pain (polyarthralgia), inflamed joints (polyarthritis), and muscle pain (myalgia), these may respond to certain treatments like hydroxychloroquine along with corticosteroids or other drugs that modify the course of rheumatic diseases (DMARDs). While there are some drugs under development that specifically target the virus’s ability to replicate inside your body, they are still being studied and are not yet approved for use in humans.
To protect yourself from Chikungunya virus (CHIKV), the best approach is to avoid getting bitten by mosquitoes. You can do this by using bug repellents containing DEET, wearing covered clothing, using bed nets, and staying in air-conditioned buildings. You should also try to reduce the number of places where mosquitoes can breed near your home, such as puddles of water. Using insecticides can also help control mosquito populations, but there are concerns about mosquitoes becoming resistant to these chemicals. Several vaccines against the virus are currently being researched, but none have been approved yet for patient use.
What else can Chikungunya Fever be?
When a patient comes in with symptoms like joint pain, high fever, and a rash, it could mean they have Chikungunya fever. But these symptoms are quite common and can indicate many different illnesses. Diseases like Dengue and Zika share not just clinical symptoms but also the same carriers as Chikungunya, making it necessary to test for all three if a patient shows these symptoms.
There are several other infections also worth considering when one presents with these symptoms, such as:
- Malaria
- Yellow fever
- Leptospirosis
- Measles
- Mononucleosis
- African tick bite fever
Chronic joint pain resulting from Chikungunya fever can be mistaken for other more common causes. It’s especially tricky if a patient with pre-existing joint disease gets infected with Chikungunya, as this can lead to worse outcomes and higher risk of health complications.
Chronic conditions that need to be considered when diagnosing this kind of joint pain include:
- Seronegative rheumatoid arthritis
- Reiter arthritis
- Rheumatoid arthritis
- Hepatitis C
- Systemic Lupus erythematosus
What to expect with Chikungunya Fever
Despite the fact that Chikungunya fever is usually not fatal, it is known for causing persistent joint pain, referred to as post-chikungunya chronic polyarthralgia. This is defined as joint pains that last for more than 6 weeks. A study conducted in 2018, involving cases of Chikungunya virus (CHIKV) from Aruba, revealed that 26% of all patients with a confirmed CHIKV infection suffered from this prolonged joint pain.
Additionally, another study in 2018 looked at cases from French Guiana in 2014. It found that amongst patients with confirmed cases using Real-time Polymerase Chain Reaction (RT-PCR, a method to detect the presence of a specific virus), 40% experienced post-CHIKV rheumatic or musculoskeletal pain after 3 months, and 31.3% after 6 months. Essentially, this means still feeling pain in joints or muscles several months after the initial infection.
Possible Complications When Diagnosed with Chikungunya Fever
Chikungunya fever often leads to chronic arthritis, which is its most prevalent and serious after-effect. It can also cause certain eye-related issues. These might include conjunctivitis (redness or irritation of the eye), optic neuritis (inflammation that damages the optic nerve), iridocyclitis (inflammation in the iris and surrounding tissues), episcleritis (inflammation of the outer coating of the white part of the eye), retinitis (inflammation at the back of the eye), and uveitis (inflammation in the middle part of the eye). The problems most commonly faced are iridocyclitis and retinitis; however, these are usually harmless and resolve on their own.
Complications of Chikungunya Fever:
- Chronic arthritis
- Conjunctivitis
- Optic neuritis
- Iridocyclitis
- Episcleritis
- Retinitis
- Uveitis
Preventing Chikungunya Fever
Chikungunya fever is a disease caused by a virus that is carried and spread by mosquitoes. This disease is mainly found in tropical and sub-tropical regions. It originally came from Asia, but has caused major health problems in the Western Hemisphere since 2013. The most common signs of this disease are high temperatures and discomfort in the joints. Some people might also experience headaches, muscle aches, and skin rashes.
You can get exposed to this disease if you travel to places where this disease is prevalent or anywhere where there are mosquitoes. Another way of getting exposed is if you’re bitten by a mosquito carrying the virus. If you’re affected, the best way to manage the symptoms is by taking enough rest, staying well hydrated, and taking acetaminophen for pain relief.
Preventing the disease from occurring in the first place is really important. This can be done by protecting yourself from mosquito bites. Wearing clothing that covers as much of your body as possible, using insect repellents containing DEET, and using mosquito nets can help to prevent mosquito bites.
It’s also possible to get other viruses from a mosquito bite, so if you have the symptoms of Chikungunya fever you should seek medical help straight away. It’s important to diagnose and treat any potential co-infections as quickly as possible.
