As we've seen with the rapid spread of Zika and Chikungunya throughout the Caribbean, Latin and South America, the introduction of a new arbovirus into a region where competent vectors and an immunologically naive population co-exist, can quickly lead to a public health crisis.
While Yellow Fever has been successfully eradicated from North America and Europe for decades, the mosquito vectors that transmit the virus are still present in some regions.
- In 2010 the Eurosurveillance Journal devoted an entire issue to The Threat Of Vector Borne Diseases, including making the case for the reintroduction of Yellow fever and dengue: a threat to Europe? by P Reiter.
- And just as with Dengue, Chikungunya, Malaria, and most recently Zika, the potential for limited re-introduction of Yellow Fever to the United States is not zero (see Could Yellow Fever Return to the United States? by Peter Hotez and Kristy Murray).
Although large outbreaks are unlikely on either continent - the daily arrival of travelers from countries where the yellow fever virus is circulating does pose a risk of introducing the virus into the local mosquito population - making localized outbreaks possible.
Places like Florida and Southern Texas are probably at greater risk of seeing local transmission than most of Europe, but the ECDC has released the following Rapid Risk Assessment that makes it clear that while the risks are currently very low, that situation could change.
I've only posted some excerpts, so follow the link to download and read the full report:
Main conclusions and options for response
A travel-associated case of yellow fever has been reported by the Netherlands in March 2017 after travel to Suriname. During the past eight months, four travel-associated cases of yellow fever have been identified among EU travellers returning from South America. This represents a significant increase on four travel-associated cases of yellow fever among EU travellers during the last 27 years (1999 to July 2016).
Brazil has been experiencing a yellow fever outbreak since January 2017 and travel recommendations have been updated accordingly [1,2]. Therefore, EU travellers travelling to areas at risk of yellow fever in South America should be informed of the potential exposure to yellow fever virus and an individual risk benefit analysis should be conducted during pre-travel medical consultation.
The ongoing yellow fever outbreak in Brazil should be carefully monitored, as the establishment of an urban cycle of yellow fever would have the potential to rapidly affect a significant number of people. The risk of introduction and further transmission of the yellow fever virus in the EU is currently considered very low.
Advice to travellers
EU citizens who travel to, or live in areas where there is evidence of periodic or persistent yellow fever virus transmission, especially those in outbreak-affected regions, are advised to:
(Continue . . .)• Be aware of the risk of yellow fever in endemic areas throughout South America, including recently affected States in Brazil. WHO publishes a list of countries, territories and areas with yellow fever vaccination requirements and recommendations [1-3].
• Check vaccination status and get vaccinated if necessary. Vaccination against yellow fever is recommended from nine months of age for people visiting or living in yellow fever risk areas. An individual risk benefit analysis should be conducted prior to vaccination, taking into account the period, destination, duration of travel and the likelihood of exposure to mosquitoes (e.g. rural areas, forests) as well as individual risk factors for adverse events following yellow fever vaccination.
• Take measures to prevent mosquito bites indoors and outdoors, especially between sunrise and sunset when Aedes and sylvatic yellow fever mosquito vectors are most active . These measures include:− the use of mosquito repellent in accordance with the instructions indicated on the product label;
− wearing long-sleeved shirts and long trousers;
− sleeping or resting in screened/air-conditioned rooms, or using mosquito nets at night and during the day.
Advice to health professionals
Physicians, health professionals and travel health clinics should be provided with or have access to regularly updated information about areas with ongoing yellow fever transmission and should consider yellow fever in the differential diagnoses for illnesses in relation to travellers returning from affected areas.
To reduce the risk of adverse events following immunisation, healthcare practitioners should be aware of contraindications and comply with the manufacturers’ precautionary advice before administering yellow fever vaccine .