Chikungunya vs dengue: How to distinguish these two mosquito-borne infectious diseases?

01. Pathogens and vectors

The pathogens of chikungunya and dengue are different. Dengue is caused by the "dengue virus" and has 4 serotypes; chikungunya is caused by the "chikungunya virus" and has only 1 serotype. The vectors are the same, both transmitted through the bites of Aedes albopictus and Aedes aegypti.

02. Susceptible population

All populations are generally susceptible. Chikungunya infection can obtain lasting immunity. After the first infection with dengue, long-lasting immunity is generated to the same serotype, but it cannot form effective protection against different serotypes of dengue virus. Re-infection with different serotypes of dengue virus can increase the risk of severe illness.

03. Incubation period

• Chikungunya: generally 1-12 days, usually 3-7 days.
• Dengue fever: generally 1-14 days, usually 5-9 days.

04. Comparison of typical symptoms

• Similarities: Both can present with symptoms such as high fever, rash, and joint pain.

• Differences:

Chikungunya fever: Migratory joint pain, pain mainly affects small joints such as wrists and ankles. In the acute phase, multiple joints experience pain or arthritis, which may be swollen or stiff, more severe in the morning, and in severe cases, unable to move. It usually eases in 1-3 weeks. In some cases, joint pain can last for several months.

Rash symptoms usually appear on the 2nd to 5th day after onset, and are often found on the trunk, extensor side of the limbs, palms, and soles of the feet, with red maculopapular rashes or purpura. The skin between the rashes is normal, and some are accompanied by itching, which subsides after a few days and may be accompanied by desquamation.

Dengue fever: Acute onset, sudden high fever, obvious fatigue, anorexia, nausea, etc., often accompanied by severe headaches, orbital pain, systemic muscle pain, bone and joint pain, etc.

Rash symptoms are mostly congestive rash or punctate hemorrhagic rash on the face and limbs on the 3rd to 6th day of the course of the disease. Typical rashes are pinpoint hemorrhages and "skin island"-like manifestations on the limbs, which are often itchy and do not peel off. Lasts for 3-5 days.

Some patients may also have varying degrees of bleeding, such as subcutaneous hemorrhage, petechiae at the injection site, and gingival bleeding. In severe cases, subcutaneous hematoma, hematuria, and organ damage may occur.

05. Laboratory tests

Serum-specific antibodies can be detected. Dengue fever may cause a decrease in white blood cell count and/or thrombocytopenia.

06. Preventive measures

• Remove mosquito breeding grounds: turn over pots and cans, clean up stagnant water, and reduce the reproduction of Aedes mosquitoes.
• Prevent mosquito bites: use mosquito repellents, mosquito nets, and wear long-sleeved clothing.

07. Risk areas

Dengue fever is prevalent in tropical and subtropical areas, such as Southeast Asia and Guangdong, Guangxi, Hainan, Yunnan and other regions in my country; Chikungunya fever is prevalent in Africa, Southeast Asia and other places, and a local outbreak has recently been reported in Shunde District, Foshan, my country.

Key reminder: People who have recently traveled to areas where Chikungunya fever and dengue fever are prevalent should take the initiative to monitor their health. If they have symptoms such as fever, joint pain, and rash, they should go to the hospital in time for treatment and take the initiative to inform the travel history.