Friday, November 02, 2007

Invasive Species go 'round and 'round; where they'll stop, no one knows

Invasive species issues are at the very least a casual out-come of our modern efficient market place, and our world-wide assumption that we can use cultural ideas of commerce from the past while benefiting from modern technological advances. Finding new commodities to enhance our quality of life, transporting goods faster and faster, assuming that the refuse of the capital equation will somehow be taken care of, these are idea-pathways or vectors for invasive species. We, in the United States, expect to eat strawberries from New Zealand in January, because we can, and therefore will; somehow we are owed this without consideration of possible unthought-of of long-term consequences.

“On 30 Aug 2007, the Italian Ministry of Health notified, through the Early Warning and response System (EWRS) and under the revised International Health Regulations [IHR(2005)], the EU Member States, the European Centre of Disease Prevention and Control (ECDC) and the IHR contact point of the World Health Organization (WHO) regional office for Europe, about a
laboratory confirmed outbreak of chikungunya fever in the region of Emilia-Romagna in north eastern Italy.”[1] “Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. Chikungunya virus (CHIKV) is a member of the genus Alphavirus, in the family Togaviridae. CHIKV was first isolated from the blood of a febrile patient in Tanzania in 1953, and has since been identified repeatedly in west, central and southern Africa and many areas of Asia, and has been cited as the cause of numerous human epidemics in those areas since that time. The virus circulates throughout much of Africa, with transmission thought to occur mainly between mosquitoes and monkeys.”[2]

“The current outbreak of chikungunya in Italy is the 1st documented vectorborne transmission of the virus in continental Europe. The autochthonous transmission has extended beyond the initial 2 villages, resulting in the establishment of at least 3 secondary transmission foci by local mosquitoes. In addition, the transmission in the initial villages had not yet ceased at the time of our visit, more than 2 months after the initial case occurred. The importance of this event should not be underestimated and its comprehensive documentation is crucial to ensure a maximal benefit to control its spread and for future preparedness in case of similar occurrences of mosquito-borne disease transmission, in Italy and elsewhere."

"Risk for sustained virus transmission of Chikungunya virus in Italy Several factors seem to have contributed to the establishment of local transmission in continental Europe:- - the presence in high density of _Aedes albopictus_ in an area of the Emilia-Romagna region where it had appeared relatively recently and was therefore not yet covered by the vector monitoring system;- - an ecological situation favourable for the development of the vector and for virus transmission, considering the dense local vegetation and domestic backyards with plant pots and potential water containers in the 2 villages;- - the introduction of the virus by a visitor returning from a chikungunya high endemic area;- - sufficient (human) population density.”[3]

And now the interesting part for both oblivious Americans and Americans who may think that invasive species issues are unique to the United States:

"Based on the available data, it is likely that the transmission of chikungunya virus will persist in the coming weeks, probably until the end of October 2007 when the local vector activity should disappear. This may result in additional chikungunya fever cases occurring and being reported until then. It cannot be excluded that, in case of a particularly mild winter, local vector activity may persist during winter, especially in urban settings, potentially resulting in few sporadic cases which would, however, maintain mosquito-to-human transmission cycles until the spring. In addition, considering the existence of vertical (trans-ovarian)transmission, reported "in natura" in a tropical region, mosquitoesinfected with Chikungunya virus may re-appear in the spring of 2008, whenmosquito eggs hatch and vector activity starts again after the winter.”[4]

A friend of mine wrote eloquently the following:

“This is most unfortunate. The U.S. got the "lovely" invasive Asian tiger mosquito from import of used tires from Japan several decades ago. Obviously not having learned much from this mistake, the U.S. has sincepassed the ATM on to Italy so they can be miserable outdoors as well. And the Italians get the added bonus of a disease. Can anyone tell me WHY we all keep shipping mosquito infested used tires around the world that are obviously being shipped with water and mosquitoes in them? The benefit of the international used tire trade (I assume there is a benefit) cannot outweigh these disadvantages. If we can't address something seemingly simple like this (e.g., can the tires be drained or maybe chipped first?), it's hard to be hopeful about other prevention and early detection rapid response efforts against the really serious exotic pests. Seriously, can someone explain this to me? Please? Thank you”

[1] communicated by: Roland Hubner, Scientific Collaborator, Health Council, FPS Public Health
[2] CDC fact sheet
[3] communicated by: Roland Hubner, Scientific Collaborator, Health Council, FPS Public Health
[4] communicated by: Roland Hubner, Scientific Collaborator, Health Council, FPS Public Health

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