Chikungunya - Symptoms, Causes and Diagnosis

Chikungunya - Symptoms, Causes and Diagnosis

Chikungunya (pronounced chik-en-gun-ye) is a type of viral disease in humans. The Makonde language of Africa is the source of the expression, which means "bent over in pain”. It was originally found in almost 40...


Chikungunya (pronounced chik-en-gun-ye) is a type of viral disease in humans. The Makonde language of Africa is the source of the expression, which means "bent over in pain”. It was originally found in almost 40 countries across Asia, Africa, Europe, and most recently the Americas. It was first described in 1952 after an outbreak in southern areas of Tanzania.

When an outbreak appeared in 2007 in northeastern Italy, researchers were shocked because they had previously thought the illness to be "tropical”. Following its initial identification on the Caribbean island of St. Martin in December 2013, it has since spread to 14 other countries. There were 4,108 probable cases in the region as of May 1, 2014, and the Caribbean Public Health Authority declared an epidemic.

History of Disease

Following an epidemic on the Makonde Plateau at the boundary between Mozambique and Tanganyika in 1952, the disease was first identified by Marion Robinson and W.H.R. Lumsden[74] in 1955. (the mainland part of modern-day Tanzania).

The word "chikungunya" is derived from the Makonde root verb kungunyala, which means to dry out or become distorted, according to the earliest 1955 study on the epidemiology of the illness. In related research, Robinson clarified the Makonde phrase as "that which bends up." It appears that later writers missed the allusions to Makonde and thought the phrase came from Swahili, the dominant language in the area. Numerous print publications have echoed the false attribution to Swahili.

Chikungunya virus epidemics have occasionally happened throughout Africa, South Asia, and Southeast Asia since the virus was discovered in Tanganyika, Africa, in 1952, but more recent outbreaks have spread the illness over a wider area. This is consistent with molecular genetics data suggesting that it evolved in approximately 1700.

Epidemiology of Disease

Chikungunya has historically primarily affected the underdeveloped countries. An estimated 3 million infections are brought on by the illness annually.The disease's geographic range is still being altered by epidemics in the Indian Ocean, the Pacific Islands, and the Americas.Between human outbreaks, the virus primarily circulates among mosquitoes, small animals, and other non-human primates in Africa, where it is disseminated by a sylvatic cycle. Due of the high viral content in the blood of persons who are experiencing an acute infection, the virus can spread from people to mosquitoes and then back to people during outbreaks.

On numerous occasions, strains found in non-human primate hosts on the eastern side of Africa were used to establish the pathogen's transmission between people and mosquitoes that live in urban settings

The 19th century or more recent times are not yet clear from the data that is now accessible, but this epidemic Asian strain still produces outbreaks in India and spreads throughout Southeast Asia. In Africa, epidemics were frequently related to prolonged periods of rain that expanded the mosquito population. The virus has recently expanded in urban areas by cycling between people and mosquitoes.

What are the Causes of Chikungunya

The two most common carriers of the CHIKV virus are:

  •  Aedes aegypti
  •  Ae. albopictus.

These mosquitoes possess biological traits that make them effective invasive, competent vectors, and capable of setting the stage for the widespread manifestation of Chikungunya disease.

The species' fondness for human blood and its historical record of colonisation outside of its native region demonstrate its invasiveness. The physiological traits of the species that facilitate transmission, such as virus absorption with blood meals and subsequent infection of the mosquitoes' salivary glands, determine the vector competence.

Ae. aegypti - existed in the United States for more than 300 years

Ae. albopictus - existed since 1985 with differing characteristics.

Additionally, Ae. aegypti and Ae. albopictus are the carriers of other well-known illnesses like Dengue and Zika, which can occasionally co-infect people. Differentiating diseases has become a problem because of the closeness in clinical presentation and virtually same geographic distribution.

How the Disease is Transmitted

Humans typically contract chikungunya from insects. Vertical transmission—transfer from a mother to a kid during pregnancy or at birth—is one of the less popular routes of transmission.

Although there haven't been any cases documented, theoretically, organ donation and transmission through contaminated blood products are potentially possibilities during outbreaks.

The incubation phase normally lasts three to seven days, though this is rare.

Mosquitoes, their surroundings, and human behaviour are all connected to chikungunya.

Around 5,000 years ago, mosquitoes in North Africa began to adapt to the changing temperature, which led them to start looking for places where people had kept water. The ecosystems of the mosquitoes and human settlement were hence very intertwined. Humans serve as the virus's reservoir during outbreaks. Since there are large numbers of virus in the blood at the onset of an acute illness, the virus can pass from a human who is viremic to a mosquito and then back to a human.

Sign And Symptoms of Disease

  • Approximately 85% of those who have the Chikungunya virus experience symptoms, which often start with an abruptly high temperature of more than 39 °C (102 °F).
  • The fever is quickly followed by excruciating joint and muscle agony.
  •  Pain typically spreads to other joints in the arms and legs and is symmetrical, meaning that if one elbow is affected, both are likely to be.
  • In addition to fatigue and headache, Chikungunya patients commonly report back discomfort, nausea, and headaches.
  • In almost half of the individuals who are harmed, a rash appears, often with tiny bumps on the face, torso, and palms.
  • Some people have digestive problems that cause vomiting and stomach pain.
  • Chikungunya infection can have particularly harmful effects on newborns. Typically, fever, rash, and swelling at the extremities are the first signs of infection.
  • Others experience ocular problems such light sensitivity, conjunctivitis, and eye pain. Pain is typically felt in larger, more peripheral joints, including the shoulders, elbows, and knees, as well as in the wrists, ankles, and joints in the hands and fee.
  • Neurologic illnesses such as acute disseminated encephalomyelitis, Guillain-Barré syndrome, brain enlargement or degeneration, hypotonia (in neonates), and problems with visual processing.
  • The "acute phase" of Chikungunya's initial set of symptoms, which lasts for about a week, eventually passes on its own.
  • The "post-acute phase," for symptoms lasting three weeks to three months, and the "chronic stage," for symptoms lasting more than three months, are both common after the "acute phase," which affects many people.
  • Joint discomfort from arthritis, tenosynovitis, and/or bursitis are frequently long-lasting symptoms in both situations.

Pathophysiology of Infection

Urban and sylvan cycles are two that the CHIKV virus is known to spread.

  • Urban transmission, which happens when people come into touch with mosquitoes, is the main cause of the current outbreak in the Western Hemisphere.
  • Sylvatic transmission, which involves an animal, a mosquito, and a human, is prevalent in Africa.
  •  As previously indicated, Ae. aegypti served as the vector for the initial transmission of CHIKV, however inclusion of Ae. albopictus due to a mutation in the E1 envelope protein boosted the virus' fitness in this species as well as its capacity to infect vertebrates.

CHIKV moves through the lymphatic and circulatory systems, creating severe viremia, after mounting an early immune response and hiding in the lymph nodes.

It has been discovered that infected monocyte-derived macrophages are responsible for the transportation of antigen into target organs (muscles, joints, liver, and brain).

Acute symptoms are believed to be caused by an inflammatory response mediated by CD8+ (acute), CD4+ T cells, and pro-inflammatory cytokines, but chronic joint illness may be brought on by a permanent reservoir of infected monocytes in the joints.

How it Can be Diagnosed

  • Clinical - Acute start of high fever and significant joint pain would raise the possibility of chikungunya.
  • Epidemiological  - The individual must have travelled to or resided in a chikungunya-endemic area within the preceding twelve days
  • Laboratory - A lower-than-expected lymphocyte count in line with viremia is one of the laboratory criteria.

Viral isolation, RT-PCR, or serological testing can all be used to make a conclusive laboratory diagnosis.

Several chikungunya-specific genes are amplified from whole blood using RT-PCR and nested primer pairs, producing thousands to millions of duplicates of the genes to identify them.

The serological diagnosis uses an ELISA assay to measure the levels of chikungunya-specific IgM in the blood serum and needs more blood than the other techniques.

How it Can be Prevented

The best methods of prevention are to:

  1.  avoid contact with mosquitoes that transmit the illness .
  2.  reduce mosquito numbers by limiting their habitat.
  3. The main goal of mosquito control is to get rid of the standing water where mosquitoes breed and develop into larvae .
  4. if this is not feasible, insecticides or biological control agents can be added.

People should avoid getting bitten by mosquitoes by dressing appropriately, using repellent, and removing possible mosquito breeding grounds.

What is the Treatment for Disease

There isn't a particular treatment for chikungunya at the moment.

Supportive care is advised, and nonsteroidal anti-inflammatory medications like naproxen, non-aspirin analgesics like paracetamol (acetaminophen), and fluids are all effective symptomatic treatments for temperature and joint swelling.

Due to the increased chance of bleeding, aspirin is not advised.

Despite their anti-inflammatory properties, corticosteroids should not be used during the acute stage of an illness because they may suppress the immune system and exacerbate the infection.

Passive immunotherapy has been successfully used in research on animals, and clinical trials using passive immunotherapy in patients who are particularly susceptible to severe infection are currently being conducted.Passive immunotherapy involves the administration of anti-CHIKV antibodies  to people who are at high risk of getting the disease.

There is presently no antiviral therapy for the Chikungunya virus, despite tests showing numerous drugs to be effective in vitro.

Is There Any Vaccine for Chikungunya

No approved vaccines are accessible as of 2021.

In a phase II vaccine study, a live, attenuated virus was utilised to induce viral resistance in 98% of the participants tested after 28 days, and 85% of those tests still showed resistance after one year.

Although just two mutations in the E2 glycoprotein were determined to be responsible for the attenuation, 8% of individuals reported experiencing brief joint pain. Alternative vaccination methods have been created and are effective in mouse models.

What is the Prognosis of the Disease

Chikungunya has a fatality incidence that is little around 1 in 1000.

Severe consequences are particularly frequent in people over 65, newborns, and those with underlying chronic medical conditions.

Neonates are at risk because chikungunya can be vertically transmitted during delivery from mother to child, causing significant rates of morbidity because infants don't have completely functional immune systems.

Age and a history of rheumatological disease both raise the risk of chronic symptoms or joint discomfort.

Research About the Disease

More than a dozen agents are being studied as potential biological weapons, including chikungunya.

This condition falls under the category of neglected tropical diseases.

Facts About Chikungunya

  • The word, which meaning "bent over in pain," is from the African Makonde language
  • Mosquitoes are the virus's required vector—its mode of transportation.
  • The research so far suggests that there would be lifetime immunity.
  • Chikungunya cases can be either imported or indigenous.
  • You can only get chikungunya once before your body starts producing antibodies that will make you immune.
  • In 98% of cases involving outpatient care, the therapy is symptomatic.
  • In order to maintain bed rest, mosquito netting is preferred.
  • Every 6 hours of acetaminophen use is advised for pain and fever, as this is required to keep the temperature down
  • To far, neither a vaccine nor a targeted medication exist to combat the infection.
  • Chikungunya-related deaths are extremely rare and nearly usually a result of co-existing medical conditions.
  • If a mother has chikungunya while pregnant, the virus does not pass to the unborn child.
  • The mother may still transmit the illness to the baby if she develops a fever in the days leading up to or during delivery, according to reported cases.
  • Children must continuously consume fluids, whereas adults with illnesses require 2 to 3 litres of fluids per day (water, coconut water, soups, fruit juices, oral rehydration serum).