Can dengue or chikungunya be transmitted from person to person?

Transmission of Dengue and Chikungunya

Dengue and chikungunya are NOT transmitted from person to person through casual contact—both diseases require mosquito vectors (primarily Aedes aegypti and Aedes albopictus) for transmission. 1, 2

Primary Transmission Route

• Mosquito-borne transmission is the only significant route for both dengue and chikungunya in clinical practice, occurring when infected Aedes mosquitoes bite humans 1, 2, 3
• Aedes aegypti is the primary vector, with Aedes albopictus serving as a secondary vector for both diseases 1, 2, 3
• These are the same mosquito species that transmit yellow fever and Zika virus 1, 2

Viremia and Theoretical Transmission Risks

• Dengue patients are infectious to mosquitoes shortly before fever onset and for 3-5 days thereafter during the viremic period 4
• While high levels of viremia occur in dengue patients, bloodborne transmission could theoretically occur through transfusions or needlestick injuries, but this is not a documented route of person-to-person spread in clinical practice 4
• No evidence exists for respiratory, contact, or other direct person-to-person transmission for either dengue or chikungunya in the medical literature 1, 2, 3

Important Distinction from Other Flaviviruses

• Unlike Zika virus (another mosquito-borne flavivirus), which can be transmitted through human-to-human routes including materno-fetal and sexual transmission, dengue does not have these documented transmission pathways 4
• Chikungunya similarly lacks human-to-human transmission routes, though rare mother-to-child perinatal transmission has been reported during delivery when mothers are viremic 4

Clinical Implications

• Patients with dengue or chikungunya do not require isolation from other patients or family members, as they pose no direct transmission risk 1, 2
• The focus should be on preventing mosquito bites in infected patients during the viremic period to interrupt the transmission cycle 4, 5
• Healthcare workers should use standard precautions; no special airborne or contact precautions are needed 4

Prevention Focus

• Vector control and personal protective measures against mosquito bites are the only effective prevention strategies for both diseases 5
• Travelers and residents in endemic areas should be informed about mosquito bite prevention rather than person-to-person transmission precautions 5