Chikungunya

Chikungunya is a viral disease caused by the chikungunya virus (CHIKV), which belongs to the genus Alphavirus, family Togaviridae. The disease was first identified in 1953 in Tanzania and is named after the Makonde language, where "chikungunya" roughly translates to "to walk bent" or "to carry a child" due to its characteristic symptoms of joint pain and swelling.

Epidemiology:
Chikungunya is primarily spread by the bite of infected mosquitoes of the Aedes genus, particularly Aedes albopictus (Asian tiger mosquito) and Aedes aegypti. The virus is endemic in Africa, Asia, and the Indian subcontinent, but outbreaks have also been reported in Central and South America, as well as the Caribbean.
Typically these mosquitoes are infected due to feeding on infected humans, monkeys or other animals. It however does not get transmitted among people. Daytime mosquitoes are the main carriers.
Transmission occurs when an infected mosquito bites a human host, and then the virus replicates in the mosquito's body before being transmitted to another individual through a subsequent bite. The incubation period is typically 2-7 days, during which time the person may experience no symptoms or mild ones. Once symptoms appear, they can persist for several weeks.

Clinical Features:
The majority of individuals infected with CHIKV will develop symptoms within 1-3 days after being bitten by an infected mosquito. The clinical presentation varies in severity but typically includes:

1. Fever: A high-grade fever (>38 degree C) that may be accompanied by sweating, chills, and rigors.
   
2. Joint pain and swelling: This is the most characteristic symptom of chikungunya, often described as intense, burning, and debilitating pain in multiple joints (hands, feet, ankles, knees, elbows, and wrists). Swelling and inflammation are common.
   
3. Rash: A pink or maculopapular rash may appear on the skin, particularly on the trunk and limbs.
   
4. Headache: Mild to moderate headache is a frequent complaint.
   
5. Muscle pain: Generalized muscle ache and stiffness can occur.
   
6. Eye involvement: Conjunctivitis (pink eye) or uveitis (inflammation of the iris or retina) may develop in some cases.
   

In rare instances, chikungunya can lead to more severe complications, such as:
1. Neurological symptoms: Encephalitis (inflammation of the brain), meningoencephalitis (inflammation of the membranes surrounding the brain and spinal cord), or Guillain-BarrΘ syndrome (a type of autoimmune neuropathy).
2. Cardiac issues: Congestive heart failure, arrhythmias, or myocardial infarction (heart attack) have been reported in some cases.

Diagnosis of chikungunya :
A diagnosis of chikungunya is typically made through a combination of clinical evaluation and laboratory testing. The following methods are used:
1. Clinical features: A careful history and physical examination can help identify the characteristic symptoms.
2. Laboratory tests:
Serological tests (ELISA or IgM/IgG antibodies) to detect CHIKV-specific antibodies in blood or serum.
Molecular detection (RT-PCR, PCR, or whole-genome sequencing) to identify the virus in blood, urine, or cerebrospinal fluid.

Treatment and Management :
There is no specific antiviral treatment for chikungunya. Supportive care focuses on managing symptoms and preventing complications. Treatment options include:
1. Pain management: Nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin, ibuprofen, or naproxen can help alleviate joint pain.
2. Rest and hydration: Patients are advised to rest, avoid strenuous activities, and maintain adequate fluid intake to prevent dehydration.
3. Physical therapy: Gentle exercises and physical therapy may be recommended to maintain joint mobility and reduce stiffness.

Prevention of chikungunya:
Preventing mosquito bites is the most effective way to avoid contracting chikungunya. Strategies for prevention include:
1. Wear protective clothing: Cover exposed skin with light-colored, loose-fitting clothing and a hat.
2. Use insect repellent: Apply insect repellents containing DEET (20-30%), picaridin, or oil of lemon eucalyptus to exposed skin and clothing.
3. Eliminate breeding sites: Remove standing water around homes and neighborhoods to prevent mosquito populations from growing.

Vaccination:
Several chikungunya vaccines are currently in development, with some having received approval for use in specific countries. The most advanced vaccine candidate is the Sanofi-Pasteur recombinant vaccine, which has shown promising results in clinical trials.

Fever

Fever is an elevation of body temperature and defined as a core temperature higher than 38 C (100.4 F) in infants and higher than 38.3 C (100.9 F) in adults. Normal body temperature range is between 36 and 37.8 degree C (96.8 and 100.4 degree F). If a person has an oral temperature above 98.6 F (37 C), it is considered as fever. In some cases, there is a variation of up to 1 F (0.6 C). Fever is a symptom and not a disease. Fever, by itself is an indicator that the body is building an immune response to an infection. Most viruses and bacteria cannot survive at higher temperatures and fever is the body's fighting mechanism. Any body temperature up to 100 F is considered low grade fever. It is usually noticed along with sore throat, cough, joint pain, chills and nausea. Most fevers of this nature are self-limiting; and medication is given to provide comfort to the patient. Most of the time fever is only a symptom which can be treated symptomatically with antipyretics. Acetaminophen and ibuprofen are prescribed to control fever.

Fever results from the production of prostaglandin E2 (PGE2) in the hypothalamus due to endogenous or exogenous pyrogens. The cause is identified by physical examination and a thorough history - the onset of fever, level, duration, pattern if any and other symptoms.

Normally a person can sustain a body temperature of up to 104 degree F (40 degree C) with relative safety. But when the fever temperature rises above 104 ° it may cause cellular damage to brain, blood and internal organs. To prevent damage from high fever cooling treatments may be of help. Cold compresses, cold packs or sponge baths or ice bags /chemical cold packs are used to bring down the high fever.

Do not swathe a patient with fever in blankets but keep him comfortable. Bath in tepid water can help, but never ice cold water. The patient must be well hydrated. Some immunosuppressed or elderly patients might not exhibit a big rise in temperature in spite of a serious infection. Most often , CBC (complete blood count) is done to look for raised WBC count. Other useful indicators are urine test, gram stains and chest x-ray. If fever is also accompanied by abdominal pain, CT scan of the abdomen is suggested to look for possible appendicitis, diverticulitis and Cholecystitis.

The degree of fever elevation is not an indicator of the severity of the illness. Fever can be due to dengue, chikungunya, chicken pox, measles, malaria or other infections. Metabolic disturbances can cause body temperature to be elevated. In rare cases, fever is due to heart disease, serious illness, AIDS or cancer. Toxic shock, meningitis and peritonitis are other serious causes for high fever.

In some cases, the cause for fever is not easy to diagnose. Fever due to upper respiratory tract infection usually lasts for about 3-5 days.

Do not confuse fever with Hyperthermia, where the body temperature rises due to external sources. Here fever is also accompanied by palpitations, fainting, shivering, aches and confusion or hallucinations. When fever rises, the respiratory rate and heart rate rise. When children below 1 year suffer fever, they should be examined by a healthcare professional. Never use aspirin in children during a viral infection.