Information on the Ebola Outbreak in West Africa 2014
Ebola Spread Raises New Concerns, GVN Calls for Increased Resources
Baltimore, MD, 14, April 2014: The Global Virus Network (GVN), representing more than 20 countries and comprising foremost experts in every class of virus causing disease in humans, is actively monitoring the current Ebola outbreak in West Africa closely.
The current outbreak is of particular concern because it involves the most virulent known Ebola strain (Ebola Zaire) in an area of Africa where outbreaks of this virus have never before been reported.
Since the first cases of Ebola were reported in Guinea during December 2013, more than 159 suspected cases and 104 deaths have been reported [as of 11 April]. Confirmed cases have been detected in Guinea and Liberia, and suspected cases are under investigation in Mali.
Human outbreaks of Ebola in central Africa have been linked to infections acquired from infected monkeys and chimpanzees, or contact with infected humans. Ebola is a member of a group of “hemorrhagic” viruses which lead to uncontrolled bleeding and death. Ebola kills up to 90% of people infected: the case fatality rate of the current outbreak is 65%. Research conducted by a scientist in GVN’s Center of Excellence in South Africa, Dr. Robert Swanepoel of the National Institute of Communicable Diseases, has shown that fruit bats may harbor the virus without showing disease, and could be a natural reservoir for the virus. Scientists are working to understand the cycle of transmission from natural reservoirs to primates.
On 8 April, the WHO announced that the current Ebola virus outbreak in West Africa would not be contained for at least another two to four months.
Professor Alexander Bukreyev of GVN’s Center of Excellence at the University of Texas Medical Branch/Galveston National Laboratory said, “Increased international travel and rapid ecological changes in Africa suggest that we can expect Ebola and Marburg [which are closely related to Ebola] outbreaks in areas not previously affected by these viruses.” He continued, “Clearly there is a pressing need in vaccines and therapeutics against Ebola and Marburg viruses to protect populations in areas affected by outbreaks and healthcare workers working there.”
Several laboratories are working to develop vaccines and drugs to combat Ebola and other hemorrhagic fevers. On March 24, 2014, GVN reported that one of its scientific leaders, Dr. Erica Ollman Saphire at Scripps Research Institute in California had received a major grant from the U.S. National Institutes of Health to bring together expertise from around the world to speed work to create effective therapies against Ebola and related viruses. (Read the press release at http://www.gvn.org.)
Countries hardest hit by Ebola may not be able to identify outbreaks quickly enough or implement containment strategies to effectively halt sudden outbreaks. Additional human and material resources are needed to assist affected countries in addressing both short-term needs to stop the epidemic, as well as long-term needs to develop therapies and vaccines to break the cycle of animal-to-human and human-to-human transmission.
GVN is working to identify more resources and partnerships in order to help build medical virology capacity in Africa with the goal of detecting and ending outbreaks swiftly, or preventing their occurrence.
Foodborne norovirus outbreaks
Noroviruses are a major cause of viral gastroenteritis and have been detected with increasing prevalence in recent years. Noroviruses are genetically diverse and the ones, which have been detected in humans are currently divided into 5 genogroups (G) based on their capsid and/or polymerase sequences. Only GI, II, and to a much lesser extent IV are clinically important for man. Clinical symptoms including nausea, vomiting, diarrhea, and fatigue start suddenly after an incubation period of 1−3 days and normally resolve within few days. Infants, elderly people and particularly immunocompromized persons can excrete noroviruses for several months to more than a year.
Laboratory diagnosis relies mainly on PCR detection of noroviral RNA in stool samples. Antigen assays for rapid testing are also available but less sensitive and specific. They may be used in outbreaks, if testing of many persons is necessary. Several factors contribute to the ability of noroviruses to cause widespread outbreaks: high amounts of virus excreted during infection, high stability of virions in the environment, low infectious dose (10–100 viral particles). Foodborne transmission has been well-documented but may be difficult to prove in an individual outbreak and thus is often misinterpreted. The main reason for detection failure is the limited sensitivity of PCR assays if the amount of input sample material is low compared to the amount of food ingested.
End of September 2012 an extended gastroenteritis outbreak affected East Germany with 11.000 cases many of which received lunch from the same provider. Not all gastroenteritis cases were necessarily due to noroviruses; however they were the major cause. Various GI and II strains were detected in stool samples from sick patients. This fitted to a foodborne outbreak starting from highly contaminated food. The dominance of non-pandemic strains could also help to explain the lack of widespread transmission within households. Frozen strawberries delivered by a large-scale caterer were identified as the likely source both epidemiologically and by detecting noroviral RNA. These strawberries had been distributed to all affected settings, but different manifestation rates were observed due to variable handling of the frozen berries before serving.
The outbreak demonstrates the ability of noroviruses to spread quickly as a foodborne pathogen and the importance of a quick coordinated response of virologists with local, state, and federal agencies in outbreak control.
Dieter Hoffmann, München