The 2014/15 outbreak of Ebola virus disease is the largest ever reported of this deadly, highly infectious, hemorrhagic disease since its initial discovery in humans in 1976. The current outbreak was first recognized in March, 2014 in Guinea and has since crossed international boundaries into Sierra Leone and Liberia where case numbers have now surpassed those recorded in the country of origin. Due to international travel of infected individuals, both medical professionals and non-professionals, the virus has also been introduced and caused smaller outbreaks in Mali, Nigeria, Spain and the United States. A worldwide response was launched. Like the infectious agent, this approach crosses interdisciplinary, geographical, cultural and socio-political boundaries and includes research, professional and public education, clinical care and respectful, safe disposition of the remains of those who died from the illness. In this paper, we aim to reduce fears of the unknown and encourage continued efforts to conquer the epidemic by describing the nature of the infectious agent, by providing a brief overview of its history, scope, and impact.
Prof. dr hab. Janusz T. Paweska & Dr. Petrus Jansen van Vuren Centre for Emerging and Zoonotic Disease of the National Institute for Communicable Diseases, Johannesburg, South Africa
A New Pathogen in Paradise
A new virus with a strange name recently emerged in the popular press and the public consciousness. On 19 December 2013, two confirmed cases of locally acquired chikungunyavirus (CHIK) were reported on the French Caribbean island of Martinique. The World Health Organization announced that this is the first time local transmission of this virus has been detected in the Americas.
CHIK is spread by the bite of infected mosquitos such as Aedesaegypti (the yellow fever mosquito) and Aedes albopictus (the Asian tiger mosquito).
In human infections, CHIK can cause a debilitating illness often characterized by headache, fever, fatigue, nausea, vomiting, muscle pain, rash, and joint pain. It is rarely fatal, but it can lead to chronic, debilitating joint pain. The virus was discovered in 1953 in Tanzania during an epidemic of dengue-like illness, and acquired its name from a local phrase that means ‘that which bends up.’ In other words, causes pain.
Since its discovery, the virus has been responsible for outbreaks in Kenya (2004), the French island of Reunion off East Africa (2005-06), and in other locations. The Reunion outbreak resulted in 244,000 cases and 203 deaths. A 2006 outbreak in India involved more than a million cases. Travelers returning from Africa and Réunion also introduced the virus into parts of Europe.
Subsequent outbreaks in India likely were driven by the virus’ ability to adapt to the more aggressive tiger mosquito, and to acquire mutations that shortened the period of viral replication in the mosquito and thereby increased the viral load. The end result was a fast-moving epidemic.
“These observations point to one important fact that the more the efficiency with which we contain the primary outbreak of this disease, the better we are able to prevent adaptive mutations in the virus and the emergence of severe infections and explosive epidemics,” notes a member of the Global Virus Network (GVN), Dr. E. Sreekumar, at the Rajiv Gandhi Centre for Biotechnology in Kerala, India.
There is no specific antiviral treatment available forchikungunya fever. Treatment is symptomatic and includes rest, fluids, and medicines to relieve symptoms of fever and aching such as ibuprofen, naproxen, acetaminophen, or paracetamol.(Aspirin should be avoided.)
Various research groups in the U.S. and Europe are working on a vaccine. Recently, a group in the Netherlands reported on the production of a synthetic CHIK vaccine* that protected mice from infection and inflammation caused by the Réunion Island CHIK virus strain.
Like other viruses before it, CHIK has moved west into the Americas with the aid of tourists and international trade. An effective vaccine would be an important tool in controlling this emerging virus.
* Effective Chikungunya Virus-like Particle Vaccine Produced in Insect Cells. Stefan W. Metz, Joy Gardner, CorinneGeertsema, Thuy T. Le, Lucas Goh, Just M. Vlak, AndreasSuhrbier, Gorben P. Pijlman. March 14, 2013. DOI: 10.1371/journal.pntd.0002124.
Chikunguya virus (CHIKV) outbreak in St. Martin
December 20, 2013, Baltimore, MD: St. Martin, in the Caribbean, is the first country in the Western Hemisphere to experience a Chikunguya virus (CHIKV) outbreak. Global Virus Network (GVN) member of the Sweden-Estonia GVN Center of Excellence and CHIKV specialist, Andres Merits, PhD says once we know the genotype, we will have a better estimate of the potential of the virus to spread. Dr. Merits, Professor of Applied Virology, Institute of Technology, University of Tartu, Estonia, also noted, “Clinicians in the region of the Caribbean must be on high alert as CHIKV is often mistaken for Dengue fever or even malaria. Once we know the genotype, we will know more about the efficiency of mosquito transmission, and public health officials can begin to take prevention measures to contain the outbreak.” Such measures include aggressive mosquito control techniques, whereas travel restrictions are more likely to be relatively inefficient. Dr. Merits said, “I am reasonably optimistic this outbreak will not be widespread. However, this new outbreak is a stark reminder of why medical virologists worldwide must be prepared to share information and expertise quickly, and with the goal of safeguarding the health of people everywhere. We do not yet have drug therapies for CHIKV, let alone a vaccine, but scientists are close and can develop these cures if governments and the public and private sector support them.”
The following are comments from the Munich Meeting.