Chikungunya virus has reached the Caribbean and South America – and is predicted to soon cause outbreaks in the United States. For many years, the virus has remained primarily in Africa, the Indian subcontinent and Southeast Asia, the Global Virus Network (GVN) reports. Responding to the arrival of the virus in the Western Hemisphere, the Global Virus Network (GVN) announced this week the formation of the GVN Chikungunya Task Force, pooling the expertise of top virologists from around the world.
Chikungunya is a vector-borne viral disease spread by mosquitoes that is not currently found in the United States, but was first observed the West Indies in October 2013, since which it is estimated that has cause approximately 15,000 cases in the islands. The disease is expected to reach continental North America in the near future, with the first locally-acquired Chikungunya illnesses expected to be reported in the continental U.S within 12 to 24 months. Texas is high on the list of potential breakout points.
Announcement of the new GVN task force coincided with World Health Day, observed annually on April 7. World Health Day 2014’s theme was Vector-borne diseases, and According to the Centers for Disease Control and Prevention (CDC), Chikungunya (Pronunciation: “chik-en-gun-ye”) is a viral disease transmitted to humans by the bite of mosquitoes that become infected when they feed on a person infected with Chikungunya virus. Infected mosquitoes can then spread the virus to other humans when they bite. Monkeys, and possibly other wild animals, may also serve as reservoirs of the virus.The Chikungunya virus is a member of the genus Alphavirus, in the family Togaviridae.
Chikungunya fever can cause debilitating illness, most often characterized by fever, headache, fatigue, nausea, vomiting, muscle pain, rash, and joint pain. The term ‘Chikungunya’ means ‘that which bends up’ in the Kimakonde language of Mozambique. Acute Chikungunya fever typically lasts a few days to a few weeks, but as with West Nile Virus fever, which is now well-established in North America, and dengue fever — another tropical disease expected to become problematical here soon, as well as other arboviral fevers, some patients have prolonged fatigue lasting several weeks. Additionally, some Chikungunya patients have reported incapacitating joint pain, or arthritis which may last for weeks or months. According to the Centers for Disease Control and Prevention (CDC), 72 percent to 97 percent of infected people experience symptoms — far higher proportions than is true of West Nile virus and dengue. The prolonged joint pain associated with Chikungunya virus is not typical of dengue. No hemorrhagic cases related to Chikungunya virus infection have been conclusively documented in the scientific literature. Co-circulation of dengue fever in many areas may mean that Chikungunya fever cases are sometimes clinically misdiagnosed as dengue infections, therefore the incidence of Chikungunya fever could be much higher than what has been previously reported.
The CDC says Chikungunya’s incubation period can be 2-12 days, but is usually 3-7 days. “Silent” Chikungunya virus infections (infections without illness) do occur, but how commonly this happens is not yet known. Chikungunya virus infection (whether clinically apparent or silent) is thought to confer life-long immunity. Pregnant women can become infected with Chikungunya virus during all stages of pregnancy and have symptoms similar to other individuals. Most infections occurring during pregnancy will not result in the virus being transmitted to the fetus. The highest risk for infection of the fetus/child occurs when a woman has virus in her blood (viremic) at the time of delivery. There are also rare reports of involuntary first trimester abortions occurring after Chikungunya infection. Pregnant women should take precautions to avoid mosquito bites. Currently, there is no evidence that the virus is transmitted through breast milk.
There is no vaccine or specific antiviral treatment currently available for Chikungunya fever. Treatment is symptomatic and can include rest, fluids, and medicines to relieve symptoms of fever and aching such as ibuprofen, naproxen, acetaminophen, or paracetamol. The CDC says aspirin should be avoided. The disease is not usually fatal. The CDC notes that Chikungunya virus was first described following an outbreak in southern Tanzania in 1952, and first isolated from the blood of a febrile patient in Tanzania in 1953. It has since been cited as the cause of numerous human epidemics in many areas of Africa and Asia and most recently in limited areas of Europe.
With the Caribbean area’s high level of tourism, the virus will have many opportunities to quickly spread to other locations. In addition, there is an indication that the type of mosquito connected to the Caribbean cases is common in the United States, Mexico and parts of South America. In February, The Public Health Agency of Canada issued a travel health notice saying cases have been confirmed in the Caribbean Islands of Saint Martin, Dominica, Guadeloupe, Martinique, Saint-Barthelemy and the British Virgin Islands — all popular vacation spots for Canadians and Americans. The University of Texas Medical Branch (UTMB) at Galveston has been monitoring the spread of Chikungunya virus for some time, and notes in a release that scientists have long known that the process they call “viral emergence” involves a wide variety of factors. Some are changes in the environment, either generated by natural causes or human activity. Others are internal, arising from accidental changes — mutations — in the virus’s genetic code. Photo Caption: Image courtesy UTMB Health
“Viruses are among the leading causes of death and disability in the world. Being able to quickly bring together the most knowledgeable researchers without regards to borders and political agendas to address viral threats such as chikungunya is paramount,” says Dr. Robert Gallo, Global Virus Network co-founder and scientific director and director of the Institute of Human Virology at the University of Maryland School of Medicine in a GVN release. Dr. Gallo became world famous in 1984 when he co-discovered HIV as the cause of AIDS. Little was known then of the mysterious disease that was fast becoming the deadliest in medical history. Since then, Dr. Gallo has spent much of his career trying to put an end to HIV and other viral, chronic illnesses.
The GVN Chikungunya Task Force is composed of 16 virologists representing nine countries, including the United States, the United Kingdom, France, Ireland, Sweden, Grenada, Estonia, South Africa, and Thailand. It is being led by Dr. Scott Weaver, John Sealy Distinguished University Chair in Human Infections and Immunity and Director, Institute for Human Infections and Immunity at the University of Texas Medical Branch, Dr. John K. Fazakerley at the Pirbright Institute in the U.K., and Dr. Marc Lecuit at the Institut Pasteur in Paris. All of the participating members are affiliated with GVN Centers of Excellence. Much of the group’s effort will focus on issues related to more rapid identification of infections, improved treatment options and development of an effective vaccine.
“There is every expectation that chikungunya will continue its spread from the Caribbean into Central and South America, Mexico, and eventually the United States,” says GVN Chikungunya Task Force co-chair Dr. Scott Weaver. “As we gear up to address chikungunya in the Americas, we have much to learn from other countries where the virus has been endemic for many years. And, this new global collaboration will help all countries, particularly as we prepare for vaccine trials.”
Developing a vaccine against Chikungunya is a key focus of Dr. Weaver’s work at UTMB, and as Scientific Director of the Galveston National Laboratory and a member of the Sealy Center for Vaccine Development. In addition, as the range of the virus expands, new and rapid diagnostics will be needed to differentiate Chikungunya infections from other viral illnesses, and to determine where best to deploy any future vaccines.
A UTMB research article published in August, 2011 in the journal PLOS Pathogens titled “Novel Chikungunya Vaccine Candidate with an IRES-Based Attenuation and Host Range Alteration Mechanism” (PLoS Pathog. 2011 Jul;7(7):e1002142. doi: 10.1371/journal.ppat.1002142. Epub 2011 Jul 28.) was coauthored by Dr. Weaver and colleagues, and contains a great deal of background on the Chikungunya virus. The article describes in thoroughgoing detail the process of developing a Chikungunya (CHIK) vaccine, and concludes that a novel CHIK vaccine candidate, CHIKV/IRES, was generated by manipulation of the structural protein expression of a wt-CHIKV strain via the EMCV IRES. This vaccine candidate exhibits a high degree of murine attenuation that is not dependent on an intact interferon type I response, yet is highly immunogenic and protects against CHIKV challenge. They noted that this promising vaccine candidate is being tested in nonhuman primates to determine if it is suitable for evaluation in humans.
“The GVN Chikungunya Task Force will help speed the process to creating vaccines and much-needed diagnostic tools,” says Global Virus Network’s president Dr. Sharon Hrynkow. ”We look forward to working with public health agencies, including the Pan American Health Organization, to prevent the spread of chikungunya and mitigate human suffering.”
Among Dr. Hyrnkow’s first priorities upon being appointed GVN president in 2012 was expansion of fellowship and exchange programs among the GVN’s 30 centers of excellence in more than 20 countries, and establishment of seed funding for innovative and international collaborative projects on high-risk pathogens.
“The need for a Global Virus Network linking the world’s greatest medical virologists is urgent,” says. “This is a time when the global community is becoming increasingly aware of the need for biomedical research and training in order to combat pandemic threats from viral disease. I could not be more thrilled to be asked by Bob Gallo and his esteemed colleagues to lead the GVN at such a critical time.”
Dr. Hrynkow says Global Virus Network envisions a world in which viruses do not ruin lives and economies, and that the organization is unique — bringing together experts on every medically relevant virus, and it fostering a community that will share expertise and knowledge, the very foundations of a strong scientific enterprise. The GVN advances research, supports training of tomorrow’s virologists, educates communities about viral threats and the promise of research, and advocates on behalf of the medical virology community worldwide.
The GVN’s Mission is to strengthen medical research and response to current viral causes of human disease and to prepare against new viral pandemic threats, and the organization supports its scientists through small grants that allow new lines of research to move forward. In outbreak situations, GVN experts stand ready to provide critical insights that will be integral for containment and prevention measures. GVN provides authoritative science-driven information to the public and policymakers about viruses and vaccines through a spectrum of outreach initiatives and digital forums, and works with governments and research funding agencies worldwide to ensure that budgets for research and training are increased to meet the critical demands of today.
Dr. Hrynkow maintains that a strong GVN is an essential defensive mechanism against the viruses that cause illness and death today. And, as history reminds us, a strong GVN will be essential as newly emerging viral threats are discovered.
In a blog entitled “Are We Prepared For The Next Viral Disease Threat?” Drs. Weaver, Gallo & Hrynkow note that vector-borne viruses — meaning those transmitted to people by an animal or insect — threaten half the world’s population and are responsible for millions of human infections annually. Various mosquitoes and ticks transmit a subgroup of these viruses that are called arboviruses.
The authors observe that there are over 100 known arboviruses that infect humans and can cause neuroinvasive diseases like encephalitis, febrile illnesses and hemorrhagic fevers. Except for yellow fever, tick-born encephalitis and Japanese encephalitis, there are no commercially available vaccines for most arboviral disease.
As the world becomes flatter and the globe opens to new opportunities for international trade and travel, viruses that used to be confined to “over there” are increasingly coming “over here,” and they are arriving sooner rather than later, they say, noting that unfortunately, few places where these diseases spread have the laboratory capabilities to carry out efficient testing for vector-borne diseases, and that Latin American countries in general are not prepared with sufficient diagnostic facilities and reagents, and the inability to test for chikungunya locally has, for example, delayed and perhaps prevented timely confirmation of suspected cases in the Caribbean and possibly other parts of the Americas.
The imbalance in global preparedness to deal with an emerging global public health crisis highlights the need for an international, collaborative effort among leading scientists to find solutions to the growing problem of vector-borne viruses before they reach pandemic levels. The GVN task force is reviewing the state of the science and potential research opportunities, identifying potential funding sources to support new research, and training the next generation of researchers to deal with this growing threat. The task force includes experts from countries that have addressed chikungunya in the past, including Thailand, Italy and France, so that lessons learned can be shared, along with expertise and resources.
Meanwhile, the CDC says the best way to prevent Chikungunya virus infection is to avoid mosquito bites. Chikungunya prevention methods are similar to those for other viral diseases transmitted by mosquitoes, such as dengue or West Nile, and include use of insect repellent containing DEET, Picaridin, oil of lemon eucalyptus, or IR3535 on exposed skin; wearing long sleeves and pants (ideally treating clothes with permethrin or another repellent).
Have secure screens on windows and doors to keep mosquitoes out. Additionally, persons with Chikungunya fever should limit their exposure to mosquito bites to avoid further spreading the infection. The person should use repellents when outdoors exposed to mosquito bites or stay indoors in areas with screens or under a mosquito net.
Read the Traveler’s Health Yellow Book for more information on Protection against Mosquitoes, Ticks, Fleas & Other Insects and Arthropods.
Besides taking precautions against mosquito bites. The Public Health Agency of Canada website has advice and up-to-date alerts on viral, parasitic and bacterial disease outbreaks in various countries.
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