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In September 2023, several people Dengue fever A dengue fever outbreak has occurred in Paris, France. The presence of this mosquito-borne disease is notable for two reasons: it is the furthest north ever recorded and there was no evidence of recent travel in any of the cases, indicating that dengue fever may be transmitted locally in northern Europe.
These facts are important for hosting the 2024 Olympics. France is Ten million Athletes, spectators, officials and tourists will gather in Paris for the event. The French government is aware of the risk of dengue fever. In Paris, Hundreds of sites We regularly test for the presence of dengue-carrying mosquitoes. Is this enough?
The concept of Super spreader Super-spreaders in infectious disease epidemiology are not new. They essentially mean that a small portion of the population, perhaps just one person, is responsible for most cases. Well-known super-spreaders in history include “Typhoid Mary”Mary Mallon was an asymptomatic carrier of typhoid fever and may have infected over 100 people.
read more: Dengue: Brazil’s one-dose vaccine could be a game changer in fight against fever
Research published in the journal Nature It has been suggested that 85% of COVID cases in Hunan, China, are due to approximately 15% of the population. Analysis from Peru The extent of superspreading suggests that more than half of cases occur in 8% of inhabited spaces. (It is important to note that dengue can only be transmitted by the bite of a dengue-carrying mosquito, not directly from another human.)
This is not the first time the Olympics have been identified as a risk factor for a virus outbreak. It was about to be postponed Due to fears of Zika Aedes aegypti mosquito.
In the end, my worries were resolved. No reported cases.
Concerns that COVID-19 could spread through the Tokyo Olympics led to drastic measures to curb the spread of infection, even though there were very few cases within the Olympic bubble. Increasing number of cases Among the general public.
So what is different about Paris?
Aedes aegypti This is a significant increase from 2016, when the number of dengue cases increased dramatically around the world during the same period. In 2016, 5.2 million cases were reported worldwide. By mid-2024, it is already estimated that 7.6 million.
read more: Viruses can change their smell to attract mosquitoes, new study in mice finds
The Olympics are expected to draw visitors from more than 200 countries to France, many of which have already experienced dengue outbreaks this year.
The Paris Olympics Super-spreader eventsSeveral factors must come together: enough mosquitoes, enough susceptible individuals and Someone who is already infected, enough time, and enough mosquito bites.
Aedes albopictus mosquitoes are perfectly adapted to the urban environment of Paris. They only need a small amount of water in a small container to lay their eggs. They feed mainly on humans at dawn and dusk. The eggs themselves can survive for months in dry conditions. When they become wet again, the eggs hatch.
read more: Dengue in France: A tropical disease in Europe may not be rare for much longer
What makes this situation potentially dangerous for Paris is that some of these mosquitoes may already be infected with dengue fever. Inherited from motherThis could significantly reduce the number of bites needed to start an epidemic.
A single mosquito bite on an infected athlete or spectator during the Olympics could spread the disease within a week – female mosquitoes can lay up to 200 eggs at a time.
Most dengue cases are asymptomatic. People infected before or during the Olympics may not know they are carrying the virus. They could unknowingly carry the virus back to their home countries and cause an outbreak there.
Whether or not people get sick, they can carry the virus and spread it through mosquito bites. Aedes aegypti mosquito.
This year’s Rio Carnival saw an outbreak of dengue fever just days before the event. A public health emergency is declaredBut the event was not canceled.
There is no public health emergency in Paris because the event itself is a risk factor: anyone who lives, works, visits, competes, volunteers or is even simply passing through Paris during the Olympics is part of a larger risk. Natural Experiment It doesn’t matter if they know it or not.
