Chikungunya refers to an an infection brought on by the Chikungunya virus, an alphavirus of the Togaviridae household. Like its shut relative, the Semliki Forest virus, the Chikungunya virus is transmitted from human to human through mosquito bites.
Chikungunya is characterised by fever, joint and muscle ache, and rash. The illness was found in Tanzania in 1952 and has been recognized in over 60 international locations since that point. The phrase “Chikungunya” means “that which bends up” within the Makonde language, spoken by a gaggle indigenous to Tanzania and Mozambique. It’s thought that this time period was coined to explain the posture of sufferers affected with extreme illness.
Transmission
Mosquito species that carry Chikungunya embody Aedes aegypti within the tropics, Aedes albopictus within the tropics and colder areas, and roughly one dozen Aedes species in Africa, together with Aedes furcifer and Aedes taylori. Transmission happens after a mosquito bites somebody contaminated with Chikungunya and subsequently bites another person. Mosquitos choose up the virus from human blood; the chikungunya virus replication occurs contained in the mosquito and might be transmitted through salvia. As soon as a mosquito acquires the virus, it’s going to doubtless carry it for the remainder of its life. Proof reveals that some animals, together with non-human primates, rodents, and birds, might act as reservoirs for an acute Chikungunya virus.
Indicators and Signs
Indicators and signs of Chikungunya develop after a 2-12 day incubation interval. Instances differ in severity, and asymptomatic an infection might happen. The speed of asymptomatic circumstances is between 4% and 28%.
Instances usually start with an abrupt onset of fever. Polyarthralgia happens in 70% of circumstances, normally involving small joints. Swelling of joints can also happen, sometimes with out fluid accumulation. In higher than 50% of circumstances, a maculopapular rash on the palms, soles, limbs, torso, and/or face is current. This rash might progress to desquamation. Fever typically resolves inside one week, however joint ache might persist for months. A “saddle-back fever curve” is usually seen, with fever resolving and returning. Reasonable to extreme lymphopenia is commonly famous. Thrombocytopenia, leukopenia, elevated liver enzymes, anemia, and elevated creatinine can also be noticed.
Facial and neck erythema and conjunctival suffusion could also be famous as signs. Headache, photophobia, retro-orbital ache, pharyngitis, nausea, and vomiting can happen. Typically, pneumonia and dry cough are seen. Pruritus is frequent. Sufferers might complain of exhaustion and insomnia as signs as nicely. Signs of Chikungunya can persist from one week to a number of months. Residual continual joint ache might proceed in some circumstances. Persistent illness is extra frequent in older sufferers and sufferers with prior rheumatological illness.
Chikungunya may trigger neurological and ophthalmologic problems. Eye involvement might embody retinitis, retinal detachment, optic neuritis, uveitis, dendritic lesions, and Fuchs heterocyclic iridocyclitis. Neurological manifestations embody altered psychological perform, encephalitis, seizures, myelopathy, Guillain-Barré syndrome, bulbar palsy, acute flaccid paralysis, focal neurological deficit, and sudden sensorineural listening to loss.
Further uncommon problems of Chikungunya embody hemorrhagic syndrome, cardiovascular shock, arrhythmias, myopericarditis, renal failure, rhabdomyolysis, and thrombocytopenic purpura.
Kids with Chikungunya usually tend to expertise neurological and dermatological signs and fewer more likely to have arthralgia. Transplacental virus transmission might end in neonatal encephalopathy, neonatal respiratory misery, sepsis, necrotizing enterocolitis, and cardiologic problems. Infants contaminated in the course of the perinatal interval might expertise fever, rash, peripheral edema, lymphopenia, and thrombocytopenia. Congenital and perinatal infections are related to poor neurodevelopmental outcomes. Transmission of Chikungunya through breastfeeding has not been famous.
Fatalities from Chikungunya are uncommon, occurring in about 1 per 1,000 circumstances. Fatalities are extra frequent in newborns and people with a number of medical comorbidities. Using NSAIDs earlier than hospitalization is related to a rise in illness severity. An infection with Chikungunya is more likely to shield in opposition to future ailments.
Prognosis and Therapy
A prognosis of Chikungunya needs to be thought of in people dwelling in – or having traveled to – areas with identified outbreaks presenting with acute onset of fever and joint ache. Dengue fever and Zika virus an infection needs to be thought of in a differential prognosis of Chikungunya. They’re additionally carried by Aedes species mosquitoes and will current with comparable indicators and signs.
PCR, serology, and viral tradition can be utilized for laboratory affirmation of Chikungunya. Chikungunya is assessed as a biosafety level-3 pathogen, and samples needs to be dealt with accordingly. Blood-borne transmission from sufferers to healthcare employees and laboratory personnel have been documented.
Sufferers with Chikungunya are handled with supportive care, together with hydration and ache administration. It is very important forestall mosquito bites in the course of the first week of sickness to forestall extra transmission.
Chikungunya Outbreaks
Between 1952 and 2013, virus outbreaks have been recognized in Africa, Asia, Europe, and the Indian and Pacific Oceans. In 2013, circumstances have been first recognized within the Americas and nations of the Caribbean, and as we speak the vast majority of circumstances happen in these places – the place populations don’t have any preexisting immunity.
Over the previous decade, the international locations that reported most circumstances of Chikungunya have included Haiti, Dominican Republic, Guadeloupe, Martinique, El Salvador, Honduras, Nicaragua, Columbia, Bolivia, Brazil, Ethiopia, Chad, India, Laos, and French Polynesia. When you’ve got a GIDEON account, click on to discover Chikungunya Outbreak Map.
Between 2004 and 2006, an outbreak of Chikungunya that started in Kenya resulted in 500,000 circumstances in international locations of the Indian Ocean, together with one-third of the inhabitants of La Reunion Island. This outbreak unfold to India, the place nearly 1.5 million folks have been contaminated. Ongoing outbreaks have been occurring in Brazil since 2014, with over 300,000 infections occurring in 2016. It’s thought {that a} mutation occurred round 2005 that enabled the virus to outlive in Aedes albopictus; having this extra species as a vector has fueled latest outbreaks.
Native transmission was reported for the primary time in Europe in 2007, with 197 contaminated people in northern Italy. The supply of this outbreak was traced to a single particular person who had returned from India with the an infection. A second outbreak occurred in Europe in 2014, centered primarily in France and the UK and leading to about 1500 cases of an infection.
In 2014, native virus transmission was recognized within the territories of the United States for the primary time, with 4,659 circumstances occurring between American Samoa, Puerto Rico, the U.S. Virgin Islands, and Florida. Since then, the speed of native transmission in america has decreased yearly, with 179 cases occurring in 2016, 8 cases in 2018, and no cases in 2020.
Prevention
There’s at the moment no vaccine to forestall Chikungunya. The CDC recommends utilizing the Environmental Safety Company (EPA)-registered insect repellents when touring to areas with outbreaks to forestall this viral an infection. Sporting lengthy sleeves and pants may cut back transmission, as can sleeping in locations with air con and window and door screens. The CDC recommends utilizing 0.5% permethrin to deal with clothes and equipment to repel mosquitos.
Throughout outbreaks, measures needs to be taken to manage mosquito populations by decreasing pure and synthetic water-filled habitats the place they might breed. Any objects that will maintain water, comparable to swimming pools, buckets, planters, and trash containers, needs to be often emptied and cleaned.
