There’s a lot of literature on Ebola hemorrhagic fever (EHF) and its sibling Marburg, dating to decades in the past. Culled from a number of academic papers, here are 5 interesting things, mysteries of sorts, about this hemorrhagic fever.
I. MYSTERIOUS TRANSMISSION
- Although we think we know how it is transmitted, some cases have never been resolved as to point of origin. One such case occurred in 1995 in Zaire which is now the Democratic Republic of the Congo.An academic paper described “a 42-year-old male charcoal worker, a Seventh-Day Adventist [who] had not eaten monkey meat or been in detectable contact with another EHF case-patient…His charcoal plot was on the edge of a dense forest and under a dense forest canopy. During his woodcutting forays and charcoal burning pit diggings, he was exposed to a wide array of possible vectors and, presumably, the natural reservoir.” In all, approximately 2 dozen people were infected via the worker. [https://web.stanford.edu/group/virus/filo/eboz.html]
II. NEGATIVE AIR FLOW AND ISOLATION/CONTAINMENT UNITS
- As the Centers for Disease Control head Tom Frieden prepares to answer questions posed by Congress, a manual published by the World Health Organization in 1998 might be useful. That manual, Infection Control for Viral Haemorrhagic Fevers in the African Health Care Setting, contains information on setting up isolation facilities in areas where resources are limited.
Among the advice is an instruction to turn off air conditioning “to prevent spread of droplets.” This may be useful in facilities without sophisticated containment rooms when a potential case presents. Isolation units rely on negative air pressure so that contaminated air is not recirculated. [http://www.who.int/csr/resources/publications/ebola/whoemcesr982sec1-4.pdf]A manual published by the Interdepartmental working group on Tuberculosis (United Kingdom) noted: “Building ventilation, whether natural or mechanical, serves to dilute droplet nuclei in the air and is the single most important engineering control in the prevention of transmission of airborne infections.” While CDC says Ebola is not airborne, potential spread of fluids from projectile vomiting makes air flow a concern. [http://www.md.ucl.ac.be/didac/hosp/architec/UKVentilation_TBC.pdf]
III. EBOLA IN HUNTER COMMUNITIES
- A survey conducted in 1992 offers some idea about Ebola transmission from animals hunted for food. “Ethnic background appeared to be an important risk factor influencing filovirus exposure in the forest communities. The filovirus antibody prevalence among 21–40 years old male Aka Pygmy hunter-gatherers was significantly (P = 0 03) 3 times higher (37.5%) than that in similarly aged male Monzombo and Mbati subsistence farmers (13.2%).” [http://trstmh.oxfordjournals.org/content/87/5/536.short]
IV. QUESTIONS ABOUT AIRBORNE TRANSMISSION
- In September, 2014, two authors described by the University of Minnesota’s Center for Infectious Disease Research and Policy as national experts on respiratory protection and infectious disease transmission urged health organizations to deal with Ebola as though it could be airborne. Lisa M Brosseau, ScD, and Rachael Jones, PhD noted “unclear modes of transmission” as one reason to “favor more conservative measures.”The experts wrote, “We believe there is scientific and epidemiologic evidence that Ebola virus has the potential to be transmitted via infectious aerosol particles both near and at a distance from infected patients, which means that healthcare workers should be wearing respirators, not facemasks.” If you’re a healthcare worker, or have such a professional in your family, this is a must-read article. [http://www.cidrap.umn.edu/news-perspective/2014/09/commentary-health-workers-need-optimal-respiratory-protection-ebola]
V. QUESTIONS ABOUT PLANTS AND VIRULENT STRAINS
- An article in The Journal of Infectious Diseases (UK, 1999) pointed out potential for Ebola’s viral evolution: “Such viruses may have separate life cycles or may give rise to virulent strains by mutation.”The article also posed an idea about Ebola originating in plants: “Marburg and virulent Ebola viruses are maintained in hosts that are rare and have little contact with humans or do not readily transmit virus. Bats (particularly solitary microchiropteran species) are leading contenders as reservoir hosts. Virus transfer to humans occurs by contact with the primary reservoir or via an intermediate animal that acquired infection from the reservoir and is, in turn, hunted by humans. An interesting possibility is that filoviruses may be arthropod or plant viruses, with non-blood-feeding arthropods transmitting the virus to intermediate hosts or humans during oral ingestion or envenomation.” [http://jid.oxfordjournals.org/content/179/Supplement_1/S127.abstract 1999]
Despite an abundance of literature, Ebola, as many other viruses do, poses a challenge to those who study its origins, development, and treatment protocol. Hopefully, those within the federal bureaucracy are taking advantage of the vast amount of research, surveys, and studies already undertaken on this often lethal virus.
While the CDC’s Frieden has stressed the need to downplay fear in order to avoid jolts to economic interests, this approach contrasts sharply with an abundance of attention from both government and media to H1N1 influenza in October, 2009. President Barack Obama declared a national emergency. Americans may remember then-Health and Human Services director Kathleen Sebelius showed Americans how to sneeze properly during one of many appearances on national TV networks [See featured photo above, snipped from CNN video].
(Analysis by Kay B. Day/Oct. 16, 2014)
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