Check the situation in Singapore and you will see that despite huge prevention work they are not able to block the transmission pathway neither for Dengue nor Chikungunya in 2013. This may be found in : http://www.moh.gov.sg/content/moh_web/home/statistics/infectiousDiseasesStatistics/weekly_infectiousdiseasesbulletin.html

In general there is no way, the virus will come, transported by the primary hosts and this will be driven by the ongoing climate changes.

It's much more important to exclude this virus from blood and blood products. There are several ways. The most expensive is the introduction of a respective NAT testing for blood, stem cell donors, organ donors, etc.. The better way would be the introduction of a respective question (stay in the respective regions...) in the donor questionnaire. Those donors has to be excluded from the donation of living cells (RBC, PLT, organs, stem cells) at least for the maximal duration of the incubation time.

For the physicians it's important to be aware the a "new" disease will be present in the patients. Currently most of the infections will be imported but as we have seen in Europe, Dengue, Malaria, West Nile, Tribec, Tahynia, and many other infectious diseases become more and more present. This happens due to changes in the behavior of the primary hosts (birds, insects, ...) and the virus carriers.

OK Stephan but by chance the virus is not really circulating in patient without clinical sign and thus should be normally excluded. But yes if you don't care of the clinical status of the organ donnor they may present risk as remember by my collegue Thérèse Couderc from Pasteur during the acute phase of chikungunya.

Couderc T, Gangneux N, Chretien F, Caro V, Le Luong T, Ducloux B, Tolou H, Lecuit M, Grandadam M. Chikungunya virus infection of corneal grafts. J Infect Dis 2012 ; 206(6), 851–859. doi:10.1093/infdis/jis296

Hi Pierre, sure the virus circulates in the insects and the primary hosts. As normally in viruses (formerly classified as ARBO = arthropod borne) an transfer of the virus between humans is only possible by blood, blood products, organs, ...

There are many infections known. West Nile is one of the last ones. TBE, Lyssa and many other viruses were successfully transmitted from donors without clinical signs. That's one of the problems of this viruses, that humans are not the primary host. For my knowledge it's unknown how much of the infected persons will get clinical symptoms.

David: Alas, it will be very difficult to prevent chikungunya virus from reaching North America and then initiating ongoing transmission. Look for it first in countries with high incidences of dengue virus, indicating abundant Aedes mosquito virus vectors. Once introduced into the mainland Americas tropics, thee will be little to stop it. Mosquito vector control measures have not been adequate to eliminate dengue virus transmission. They will not be adequate to prevent or eliminate chikungunya virus transmission either.

Thomas; even though it has been difficult to eradicate the dengue virus in some south American countries, the control of the spread of the disease by means of controlling the vector is an important preventive measure, using similar global strategies set forward the WHO for the spread of Dengue, which consider five technical elements that may reduce the burden the disease.

Chikungunya is a viral disease transmitted by aedes mosquitoes especially Aedes aegypti and Aedes albopictus. It was associated with dengue geographical distribution. The ideal prevention and control method through vector control and especially breeding sites elimination.

A large outbreak of Chikungunya virus occurred for the first time in Italy in the late summer 2007, with a huge number of cases of febrile illness in an area of the Emilia-Romagna region, near the Adriatic Sea. Aedes albopictus, the main vector of the virus, was introduced in Italy in the late '80s or in 1990-1991. A warehouse of a tyre retreading company importing used tyres infested with mosquito eggs from Atlanta, Georgia, USA was the first recognized source of infestation.... and in the end: "despite efforts made to control the spread of A albopictus mosquitoes, they rapidly colonised almost the entire country, showing a high degree of fitness". See the paper http://www.sciencedirect.com/science/article/pii/S0140673607617796.

Viraemic travellers from endemic areas were identified as the virus source for the initial transimission cycle.

So, prevent the introduction of the virus in areas of the USA where competent vectors are abundant, will be really challenging. Mild febrile illnesses in travellers from endemic/epidemic areas are not easily detectable, and special effort is needed in terms of "risk-based surveillance". Probably, modelling dynamics of the infection including also other risk factors for the introduction of the virus would be of further help (e. g. infected mosquitoes transported by aircrafts, transovarial transmission, demonstrated in some experimental conditions etc...) for risk assessment and decision-making.

Once a transmission cycle starts, it is very, very hard to face the problem through "control measures" (including population control of mosquitoes...)

I'm fully agree with Antonio and Thomas. Thus the only good way will be to got a vaccine - there are numerous preclinical trials now more or less advance. One of them is lead by an European consortium: ICRES. I would like to highlight it : http://www.icres.eu/

To stephan, most of the population study during chikungunya epidemic shown that in opposite to West Nile (as an example) less than 5-10% of infected patient present NO clinical signs. And in all cases we have no idea of their viral load taking in account that to promote transmission to mosquitoes viral load have to be higher than 10 000 pfu per ml.

A Chikungunya virus epidemic otbreak occurred during summer 2007 in Ravenna and in some other areas of Emilia Romagna region in Italy. The affected area has been known for many years as a region with a high concentration of Ae. albopictus. The index case was a man coming from an epidemic area (Kerala, India) and the local transmission was sustained by Ae. albopictus. An active surveillance system for the identification of all suspected cases, based on weekly telephone calls to General Practitioners and emergency department, was implemented during the event. Measures for controlling the population of asian tiger mosquito were implemented in all areas where cases were reported (use of fast acting insecticide for three days consecutively in public and private space and antilarval measures house to house within a 300 m radius of the residence of a cluster ). The last case occurred on 29th of september. After the outbreak Emilia Romagna Regional Authority implemented a regional programme for the fight against the asian tiger mosquito tiger and the prevention of Chikungunya based on two main pillars:

- optimization of the fight against the Asian Tiger Mosquito to reduce the pest population rate as much as possible;

- early detection of the presence of potentially viremic patients in view of an immediate implementation of health protection measures.

Since 2007 no more case of local transmission occurred in Italy.

Like dengue, despite ample warning of an increasing global threat, diminished priorities for health in many countries e.g., education and mosquito abatement, and deteriorating infrastructures e.g., drains and ditches (ideal for mosquito breeding), have weakened health protection. Unfortunately this includes many Caribbean countries where concerns for the impact of vector-borne disease on tourism have led paradoxically to reluctant recognition by the political establishment in some of them. This is self-defeating because any nation failing to take action will be more likely to become endemic. The major risk is of course for the people immediately affected, most often the poor who have limited political representation. The adequacy of their health care systems may not be sufficient to cope with epidemic surges. Clearly part of the appropriate response to the threat of importation to other regions is to refocus on prevention in those countries where such infections already pose a major burden.

Reference: White F. Editorial: Climate Change and the Expanding Global Reach of Dengue Fever – Warnings Unheeded? International Journal of Medicine Public Health. 2011, 1 (3): 1.

With an increase of the international passengers, which include people with viruses also, the control of the spread of the infection is difficult. If proper vector control strategies are adopted, it is possible. lalitha kabilan

No country in the world has been able to implement vector control well enough to stop dengue except Cuba -- twice -- but it is continually reinfested with mosquitoes from abroad. No vaccine producer will make a vaccine for chikungunya because it hardly ever kills anybody. So the spread can't be stopped.

The Jack's abstract is perfect !! :-)

Yes, it is likely that spread cannot be "stopped", but it can be slowed down and the potential impact reduced. Thus, if one takes an absolute interpretation of "prevention", then importation cannot be totally prevented. However, there are degrees of "prevention efficacy" (this may be expressed as a percentage, and in other ways as well). The question as originally posed was in the context of North America, but vector borne diseases account for a large and increasing global burden; it is therefore of global public health importance that people are already affected in many countries. While thinking globally, it is important to act locally: clearly therefore part of the appropriate response is to refocus on vector control and other forms of prevention in those countries where such infections already pose a major burden, yet not taking sufficient action to protect their own populations, let alone international travelers, whether from North America or anywhere else in the world.

Reference: White F, Stallones L, Last JM. Global Public Health - Ecological Foundations. Oxford University Press. New York 2013.

Great Franklin!

One could check what the preferred vetcor of tjhe carribean virus clade is - Aedes albopictus or aegypti. To my knowledge they have slightly different preferences in habitats, aegypti prefers domestic small water collections that can be acted on.

And, develop a vaccine of course.

I agree with Norbert, they need to study the preferred vector of the virus clade in the area, and their main breeding sites, densities within them which essential in Aedes vector control.

I think the strategy of case containment and search to develop vaccine would be better than vector control. Vector control and using of repellents and personal protection against the mosquito bit are all important measures but have limited results in the mitigation of these diseases

An update of the regional situation in the Americas can be found in the on-line CDC publication Updates from the Field, Spring 2014 edition. The item on "Chikungunya in the Americas" (major focus on the Caribbean) can be found at the following URL: http://www.cdc.gov/globalhealth/healthprotection/fieldupdates/pdf/dghp-field-updates-2014-spring.pdf#page=3

chikungunya virus and dengue virus spread by same mosquito. The spread of these illness could be achieved by environmental sanitation..

Paracetamol,Vitamins A and D ,E and co enzyme Q will help in treatment and complication.These are evidence based in northern Sri lanka in 2.006

Epidemiological surveillance seems key to identify those presenting the symptoms. We have to assume that the vectors are present in the Americas (most countries have Aedes aegypti) and several of them have reported Aedes albopictus. Travelers in the region can carry the infection from places with transmission to those with vector and without active transmission, so, starting local transmission. Vector control must be strengthened and population must be aware of the imminent arrival of the virus and the risk of infection and clinical illness locally.

Chikungunya is transmitted from person to person by the bites of female infected mosquitoes Aedes aegypti or Aedes albopictus which can transmit dengue fever.

The weakest link in the transmission is the mosquito or the human host. The appropriate method of prevention could be preventing mosquito from biting human beings through use of protective materials such as insecticide treated mosquito net or skin repellants including symptomatic treatment of infected cases..

Hello Eltigani,

re: case containment-

While most infected people begin to display symptoms within two or three days of initial exposure, a significant minority of people do not display any symptoms for ten to twelve days after being bitten. Presumably during that incubation period, the viral load increases to the point where mosquitoes can transfer the virus from the primary case to others.

Techniques to confirm the presence of the virus may require between 2 days (PCR) to 2 weeks (virus isolation) to produce a result.

http://web.archive.org/web/20120908065003/http://www.searo.who.int/en/Section10/Section2246_12902.htm

.

These factors make any strategy based predominantly on case-containment flawed, (unless you plan on two weeks of hermetic quarantine for anyone traveling from risk countries).

While they can never be 100% effective, the best means of prevention at present remain protection against contact with the disease-carrying mosquitoes and mosquito control.

http://www.ncbi.nlm.nih.gov/pubmed/23912863

.

Unfortunately the most common vectors ( Aedes aegypti and Aedes albopictus) are both day-active mosquitoes, which makes it much harder to avoid bites.

re: immunisation-

I believe this is the only vaccine that has ever reached human trials;

http://www.ncbi.nlm.nih.gov/pubmed/11304054

.

However this vaccine was an attenuated live strain dependent on a minor mutation for it's attenuation, and it exhibited phenotypic instability- this means it is likely the virus would quickly evolve to infect vaccinated individuals, and there is also a possibility that the vaccine itself could revert to an infectious form.

http://www.ncbi.nlm.nih.gov/pubmed/22457519

.

Other candidates are still in animal testing;

http://jvi.asm.org/content/88/5/2858

.

http://www.ncbi.nlm.nih.gov/pubmed/21829348

.

In answer to the question that heads this thread, I do not think anything can be done to completely prevent the spread of this virus to any mainland areas of both American continents that harbor suitable vectors for person-to-person transmission. In such areas it is very likely to become endemic. As a particular nexus, Florida has a lot of air traffic to and from affected islands in the Caribbean.

Measures to directly reduce the population of vector species and to drain breeding ponds and pools, and campaigns to educate the general public, in such areas of North or South America may reduce the impact of chikungunya, dengue and similar infections.

Regards,

Paul.

P.S.

There is a closely related discussion here;

https://www.researchgate.net/post/What_is_the_risk_of_endemic_transmission_of_Chikungunya_in_the_Americas?exp_tc=tprc

.

Paul.

Recent US news story;

http://www.sciencedaily.com/videos/9a0952608eaf9aec2839178e7aaa8a3e.htm

.

Paul.

Control of vector (Aedes aegypti & A. albopictus) population must be the first and foremost choice. 

The best method available for control is the vector control. I think it is the more effective in reducing the risk.

I think there are several interventions that we can impose that might yield positive results. I just returned from the Dominican Republic and heard/saw many of the stories and struggles. Anecdotally, there appears to be a gap in knowledge and belief about the vector for chikungunya virus. Many in rural villages do not believe that mosquitos are the vector due to the rate of spread. They seem to feel it is fomites. With that, an educational campaign to increase awareness and knowledge of this disease may prove useful. Additionally, we need to consider other possible reservoirs for the virus. There have been several studies to provide evidence of links in non-human primates as well as other mammals (Chevillon 2008; Townson 2008; and Diallo 1999). With that said, it boils down to vector control to prevent the spread of this virus. Educational campaigns may prove useful in educating those most at risk to prevent further human infections.

 Folks; read this paper. It is really interesting and give some details about the invasion scenarios of the virus to three major cities of US.

I can help at any point of this paper

http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0001918

I think it is necessary to reduce vector population in endemic countries with integrated multidisciplinary vector control campaigns while  identifying the levels of failure within the system.  Eco-friendly vector control methods should be applied with active community participation and surveillance is essential for sustainable control of vector population. 

Faild !! as indicated in the Lance's blog: http://ldpsci.blogspot.com/2014/07/chikunguna-coming-to-america.html

or directly : http://www.cdc.gov/media/DPK/2014/dpk-chikungunya.html?s_cid=cdc_homepage_whatsnew_001

Thanks Abdallah for the link to that article.

Travelling to and fro to endemic areas is a risk factor for out break in  north america.So vigilent survilence is vital.

Hi Jamunanantha,

By "vigilant surveillance" do you mean of travellers who are returning from risk areas?

As I mentioned up above, while most infected people begin to display symptoms within two or three days of initial exposure, a significant minority of people do not display any symptoms for ten to twelve days after being bitten.

Presumably during that asymptomatic incubation period, the viral load increases to the point where mosquitoes can transfer the virus from the primary case to others.

Techniques to confirm the presence of the virus may require between 2 days (PCR) to 2 weeks (virus isolation) to produce a result.

http://web.archive.org/web/20120908065003/http://www.searo.who.int/en/Section10/Section2246_12902.htm

.

These factors make any strategy based predominantly on case-containment flawed, (unless you plan on two weeks of hermetic quarantine for anyone traveling from risk countries).

While they can never be 100% effective, the best means of prevention at present remain protection against contact with the disease-carrying mosquitoes and mosquito control.

http://www.ncbi.nlm.nih.gov/pubmed/23912863

.

Regards,

Paul.

There is a recent editorial from Steven Higgs in Vector Borne and Zoonotic diseases which is very well writen and take in account the previous experience of the West Nile virus: HiggsStephen. Vector-Borne and Zoonotic Diseases. -Not available-, ahead of print. doi:10.1089/vbz.2014.14.8.edit.

http://online.liebertpub.com/doi/abs/10.1089/vbz.2014.14.8.edit

Great article Pierre, thanks.

The key points Higgs makes about the difference between West Nile Virus and Chikungunya are astute. However Higgs also states that so far the only cases on the mainland US are travelers who contracted the virus overseas. The CDC media release you linked to above demonstrates that this is no longer the case.

Regards,

Paul

In this weeks Lancet;

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2814%2961185-5/fulltext

The only control will be by vaccine, if one is approved.  Travellers carrying the virus are not uncommon, and the vectors (Ae. aegypti and Ae. albopictus) are anthropophilic and have demonstrated that they are very well adapted to survival in rural and urban environments.    

I've lost track of time on this, and we are now growing accustomed to having Chikungunya in the Western Hemisphere.  Perhaps Zika is next.  In any case, I published the attached review article since I posted this question.  It only mentions Chikungunya along with other aquatic invasive threats with public health implications, but I hope the perspective piece will be of some interest to those who are following this discussion.

Article Aquatic invasive species and emerging infectious disease thr...