**8. Incubation period and treatment based on the natural course of the disease**

### **8.1 Incubation period**

The incubation period occurs when the mosquito acquires the virus from the viremic host. After an average extrinsic incubation of 10 days, the mosquitoes can then transmit the virus to a host, such as humans. In humans bitten by infected mosquitoes, disease symptoms usually appear after an intrinsic mean incubation period of three to seven days (range: 1–12 days) [115].

### **8.2 Acute and chronic**

Symptomatic or supportive treatment, consisting of rest and use of acetaminophen or paracetamol to relieve fever, and ibuprofen, naproxen, or other non-steroidal anti-inflammatory agents (NSAIDs) to relieve the rheumatic component of the disease. In patients with severe joint pain that does not resolve with NSAIDs, narcotics (e.g. morphine) or short-term corticosteroids may be used after evaluating the risk– benefit of these treatments. Patients are advised to drink plenty of fluids to replace fluids lost through sweating, vomiting, and other involuntary fluid losses [136].

#### **8.3 Sub-acute and chronic**

Recovery from CHIK will be a fairly long process (sometimes up to a year or even more) and persistent joint pain may require pain management, including long-term anti-inflammatory therapy. Although studies have shown that chloroquine phosphate provides some benefit [137], randomized, double-blind placebo-controlled trials have shown that it is not useful for treating joint symptoms [138]. Apart from pharmacotherapy, cases of prolonged arthralgia and joint stiffness can be treated with a gradual physiotherapy program [136].

#### **8.4 Isolation**

To prevent transmission to other people in the household, community, or hospital, sufferers of acute chikungunya (CHIKV) should avoid being bitten by the *Aedes aegypti* or *Aedes albopictus* mosquitoes during the viremic phase, which is usually the first week of illness. In addition, doctors or health workers visiting patients infected with CHIKV at home must also be careful not to be bitten by mosquitoes by wearing repellents and wearing long sleeves and pants [136]. One hospital-related CHIK infection has been identified in a healthcare provider due to the accidental needle puncture of a CHIK patient [139]. Some laboratory personnel also contracted CHIKV infection after handling infected blood [140]. This exposure indicates that direct contact transmission can occur.
