Photo Credit - CDC
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Although the risks to travelers to Guinea are considered to be low, and the World Health Organization does not recommended any travel or trade restrictions to the region, it is still advisable that visitors to Guinea be aware of their Ebola Hemorrhagic Fever outbreak and take basic precautions to avoid infection.
To that end, the CDC released the following Travel Notice (Alert - Level 2, Practice Enhanced Precautions) yesterday for those planning to visit the affected west African region.
Despite its infamous reputation for contagiousness and virulence, Ebola outbreaks over the past 40 years have been generally short-lived and limited geographically. Unfortunately, this week we’ve seen some media attempts to portray Ebola as potentially becoming an `airborne’ virus.
First the CDC’s Travel Notice, then I’ll return with a little more on what we know about the transmissibility of the virus.
Alert - Level 2, Practice Enhanced Precautions
Released: March 26, 2014
What is the current situation?
According to the Ministry of Health of Guinea, as of March 24, 2014, 6 cases of Ebola have been confirmed in Guékédou Prefecture. Suspected cases of Ebola, including some deaths, have been reported but not yet confirmed in Guékédou, Kissidougou, Macenta, and Nzérékoré prefectures. Suspected cases in border areas of Liberia and Sierra Leone are being investigated.
CDC recommends that travelers to these areas avoid contact with blood and body fluids of infected people to protect themselves.
What is Ebola?
Ebola hemorrhagic fever is a rare and deadly disease. The disease is native to several African countries and is caused by the Ebola virus. It is spread by direct contact with blood or body fluids of a person infected with Ebola virus. It is also spread by contact with contaminated objects or infected animals.
Symptoms include fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrhea, vomiting, and stomach pain. Skin rash, red eyes, and internal and external bleeding may be seen in some patients.
Who is at risk?
Cases of Ebola are seen sporadically throughout Africa. The risk to most travelers is low, but travelers could be infected if they come into contact with an infected person’s blood or body fluids. Health care workers and family and friends of an infected person are at highest risk.
What can travelers do to prevent Ebola?
There is no vaccine for Ebola and no specific treatment. Although travelers are at low risk for the disease, it is important to take steps to prevent Ebola.
- Practice careful hygiene. Avoid contact with blood and body fluids of infected people. Do not handle items that may have come in contact with an infected person’s blood or body fluids.
- Avoid contact with animals.
- Seek medical care if you develop fever, headache, achiness, sore throat, diarrhea, vomiting, stomach pain, rash, or red eyes.
- Health care workers who may be exposed to people with the disease should follow these steps:
- Wear protective clothing, including masks, gloves, gowns, and eye protection.
- Practice proper infection control and sterilization measures. For more information, see “Infection Control for Viral Hemorrhagic Fevers in the African Health Care Setting.”
- Isolate Ebola patients from unprotected people.
- Avoid direct contact with the bodies of people who died from Ebola.
Traveler Information
Clinician Information
Information for Airline Personnel
Earlier this week a European media outlet suggested that Ebola and Influenza could somehow `marry’, and create an airborne plague, a notion that Gregory Hartl – spokesperson for the World Health Organization – quickly dispelled.
While the idea that influenza and Ebola – viruses from two very different taxonomic families- could reassort (marry) and produce some kind of airborne `Flubola’ lacks scientific credence, it is not beyond the realm of possibility that one of the Ebola viruses could someday mutate into a more transmissible form.
Viruses are extremely adaptable, and one learns never to say `never’ when it comes to viruses. But to date, we’ve haven’t seen any evidence of human-to-human airborne transmission of the Ebolavirus.
Some of this media speculation may be due to a study that appeared in Scientific Reports in 2012, which I wrote about at some length in When Viruses Jump Cages.
Researchers placed four macaques in a wire cage inside a pig pen where pigs, infected with Ebola-Zaire, were kept. Although sharing common living space, they were separated by the wire cage. Yet, after 2 weeks of shared confinement, all four macaques had contracted the virus.
Transmission of Ebola virus from pigs to non-human primates
Hana M. Weingartl,Carissa Embury-Hyatt,Charles Nfon,Anders Leung,Greg Smith& Gary Kobinger
Article number: 811 doi:10.1038/srep00811
Abstract (Excerpt)
Here we show ZEBOV transmission from pigs to cynomolgus macaques without direct contact. Interestingly, transmission between macaques in similar housing conditions was never observed. Piglets inoculated oro-nasally with ZEBOV were transferred to the room housing macaques in an open inaccessible cage system. All macaques became infected. Infectious virus was detected in oro-nasal swabs of piglets, and in blood, swabs, and tissues of macaques. This is the first report of experimental interspecies virus transmission, with the macaques also used as a human surrogate. Our finding may influence prevention and control measures during EBOV outbreaks.
While suggestive of a possible airborne transmission of the the Ebola virus (by pigs), it should be noted that infected macaques did not pass the virus on to other macaques in similar experiments.
Additionally, this pig-to-macaque transmission occurred in an artificial laboratory setting, with prolonged-close, but-not-direct-contact, and doesn’t necessarily represent how things happen in the `real world’.
The researchers speculated that:
. . . transmission of ZEBOV could have occurred either by inhalation (of aerosol or larger droplets), and/or droplet inoculation of eyes and mucosal surfaces and/or by fomites due to droplets generated during the cleaning of the room. Infection of all four macaques in an environment, preventing direct contact between the two species and between the macaques themselves, supports the concept of airborne transmission.
This is, of course, a far cry from demonstrating human-to-human airborne transmission of Ebola, but it ought to give one pause before kissing a pig during an Ebola outbreak.
The researchers conclude by stating (reparagraphed for readability):
The present study provides evidence that infected pigs can efficiently transmit ZEBOV to NHPs in conditions resembling farm setting.
Our findings support the hypothesis that airborne transmission may contribute to ZEBOV spread, specifically from pigs to primates, and may need to be considered in assessing transmission from animals to humans in general.
The present experimental findings would explain REBOV seropositivity of pig farmers in Philippines that were not involved in slaughtering or had no known contact with contaminated pig tissues.
The results of this study also raise a possibility that wild or domestic pigs may be a natural (non-reservoir) host for EBOV participating in the EBOV transmission to other species in sub-Saharan Africa.
The Ebola-Reston virus (REBOV) mentioned above is a cousin to Ebola Zaïre, but this Asian strain has never been shown to cause disease in humans. It can be fatal in simians, however. We first looked at the discovery of REBOV in pigs, and its possible implications, back in 2008 in When Viruses Jump Species.
All of which is fascinating, but doesn’t alter that fact that for now, the risks of Ebola spreading beyond localized and limited outbreaks in Africa, remains pretty low.
