CLINICAL SYMPTOMS

• Most people who contract the chikungunya virus experience symptoms, which typically appear 3–7 days after being bitten by an infected mosquito.
• The hallmark signs are fever and joint pain, though other issues such as headache, muscle aches, joint swelling, and rash may also occur.
• Certain groups are more vulnerable to severe illness, including newborns infected around birth, adults aged 65 and older, and individuals with underlying conditions like hypertension, diabetes, or heart disease.
• While most patients recover within a week, joint pain can be intense, sometimes disabling, and may linger for months.
• Fatal cases are uncommon.

ETIOLOGY AND TRANSMISSION

Global presence: Chikungunya virus is found across Africa, Asia, Europe, the Americas, and islands in the Indian and Pacific Oceans.

Virus family: It belongs to the alphavirus group within the Togaviridae family. Related viruses that cause similar illnesses include the Mayaro virus and the Ross River virus.

Transmission:

• Infection occurs when mosquitoes bite an infected person and later feed on another individual.
• During the first few days of illness, infected people have high levels of virus in their blood (viremia), enabling mosquitoes to pick it up and spread it.
• Preventive measures include avoiding mosquito bites and receiving vaccination before travel, if recommended.

CLINICAL SYMPTOMS

• Dengue Infection has mild or no symptoms and gets better in a few weeks.
• Rarely, it can progress to severe forms such as Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) and may also lead to death.
• If symptoms occur, they usually begin 4–10 days after infection and last for 2–7 days. Symptoms may include High fever (40°C/104°F), severe Headache, Retro-orbital pain, Myalgia and Arthralgia, Nausea, Vomiting, Swollen glands, and Rash.
• Individuals with secondary infection are at greater risk of severe dengue. The symptoms of severe dengue often come after the fever has gone away and may include severe abdominal pain, persistent vomiting, bleeding gums or nose, fatigue, restlessness, and blood in vomit or stool.

DIAGNOSTICS AND TREATMENT

• The available tests include nucleic acid amplification tests (NAATs), enzyme-linked immunosorbent assays (ELISAs), and rapid diagnostic tests (RDTs).
• There is no specific treatment for dengue; pain can be managed with medication such as paracetamol (acetaminophen).
• Non-steroidal anti-inflammatory medicines such as ibuprofen and aspirin should be avoided as they can increase the risk of bleeding.

VECTOR

• Aedes mosquitoes are a vector of dengue fever.
• It is a small mosquito, black with white stripes, and is approximately 3-5 mm in size.
• Favorite breeding places include Desert coolers, Drums, Jars, Pots, Buckets, Flower vases, Plant saucers, Tanks, Cisterns, Bottles, Tins, Tyres, Roof gutters, Refrigerator drip pans, Cement blocks, Cemetery urns, Bamboo stumps, Coconut shells, Tree holes, and many more places where rainwater collects or is stored.

VACCINES

• Only one approved vaccine currently: Q-denga (TAK-003).
• Recommended by WHO for children aged 6–16 years in high-transmission areas.
• Two-dose schedule: second dose after 3 months.

CLINICAL MANIFESTATION

• The clinical presentation of Zika is frequently subtle, with up to 80% of infected individuals remaining asymptomatic.
• When illness does occur, symptoms are generally mild and typically last for 2 to 7 days. It presents as self-limiting febrile disease accompanied by rash, myalgia, arthralgia, and conjunctivitis.
• However, the virus is infamous for its neurological and teratogenic complications. In adults, infection has been linked to Guillain-Barré syndrome, a serious autoimmune neuropathy.
• Even more devastating are the fetal consequences when a woman is infected during pregnancy. The virus can target the developing foetus, leading to congenital Zika syndrome. This encompasses a tragic spectrum of alterations including stillbirth, microcephaly, limited joint movement, and visual impairments.