#15,647
Twelve years ago this week (see Dec 24th, 2008 When Viruses Jump Species) we looked at the surprise announcement that Ebola Reston - a strain found in the Philippines, but thankfully is not known to sicken humans - had been found to infect, and sicken, pigs.
First detection of Ebola-Reston virus in pigs
23-12-2008
FAO/OIE/WHO offer assistance to the Philippines
Manila/Roma, 23 December 2008 - Following the detection of the Ebola-Reston virus in pigs in the Philippines, FAO, the World Organization for Animal Health (OIE) and the World Health Organization (WHO) announced today that the government of the Philippines has requested the three agencies send an expert mission to work with human and animal health experts in the Philippines to further investigate the situation.
Ebola Reston was first discovered in crab-eating macaques - imported from the Philippines - at a research laboratory in Reston, Virginia (USA) (hence the name) in 1989. This discovery was recounted somewhat sensationally in the book, The Hot Zone, by Richard Preston.
In the October 2014 the CDC Review of Human-to-Human Transmission of Ebola Virus described the 1989 Reston laboratory outbreak and subsequent infection of personnel.
Similarly, an outbreak of Reston virus (Reston ebolavirus species, which does not cause EVD in humans) infection occurred in a quarantine facility housing non-human primates in separate cages and the transmission route could not be confirmed for all infected primates.
Multiple animal handlers developed antibody responses to Reston virus suggesting asymptomatic infection was occurring in humans with direct animal contact and implicating animal handling practices in transmission between primates
Readers with good memories will also recall in September of 2015, in Ebola Reston Discovered In Philippine Lab Monkeys, we looked at the announcement of the discovery of Ebola Reston among laboratory monkeys being kept at an unnamed research laboratory in the Philippines.
A year later, in 2016, in I'm Not Dying, I'm Just Reston, I wrote about research that made a side by side comparison of its genetic structure to the four other highly pathogenic Ebola strains, looking for subtle differences that might account for its lack of pathogenicity in humans.
Researchers found relatively few differences between Reston and the deadlier strains, and by focusing on key areas of the virus they believe affects the virulence of the virus in a human host, the authors concluded that only a few changes in one Ebola virus protein (VP24) may be needed to turn Ebola Reston into a virus that can cause human disease.
All of which brings us to a new study published yesterday in PNAS, and a press release from the NIH, which war
RESEARCH ARTICLE
Reston virus causes severe respiratory disease in young domestic pigs
Elaine Haddock, Greg Saturday, Friederike Feldmann, Patrick W. Hanley, Atsushi Okumura, Jamie Lovaglio, Dan Long, Tina Thomas, Dana P. Scott, Mikayla Pulliam, Jürgen A. Richt, Emmie de Wit, and Heinz Feldmann
PNAS January 12, 2021 118 (2) e2015657118; https://doi.org/10.1073/pnas.2015657118
Edited by Peter Palese, Icahn School of Medicine at Mount Sinai, New York, NY, and approved November 23, 2020 (received for review July 24, 2020)
Abstract
Reston virus (RESTV), an ebolavirus, causes clinical disease in macaques but has yet only been associated with rare asymptomatic infections in humans. Its 2008 emergence in pigs in the Philippines raised concerns about food safety, pathogenicity, and zoonotic potential, questions that are still unanswered.
Until today, the virulence of RESTV for pigs has remained elusive, with unclear pathogenicity in naturally infected animals and only one experimental study demonstrating susceptibility and evidence for shedding but no disease. Here we show that combined oropharyngeal and nasal infection of young (3- to 7-wk-old) Yorkshire cross pigs with RESTV resulted in severe respiratory disease, with most animals reaching humane endpoint within a week. RESTV-infected pigs developed severe cyanosis, tachypnea, and acute interstitial pneumonia, with RESTV shedding from oronasal mucosal membranes.
Our studies indicate that RESTV should be considered a livestock pathogen with zoonotic potential.
Reston Ebolavirus spreads efficiently in pigs
Finding reveals potential for spread to humans.
What
Reston ebolavirus (RESTV) should be considered a livestock pathogen with potential to affect other mammals, including people, according to National Institutes of Health scientists. The caution comes from a study published in Proceedings of the National Academy of Sciences in which the scientists found that experimental piglets infected with RESTV developed severe respiratory disease and shed the virus from the upper respiratory tract. RESTV can infect humans but is not known to cause disease. Now the scientists express concern that pigs could serve as an “interim or amplifying host for ebolaviruses.”
“The emergence of RESTV in pigs is a wake-up call as transmission into humans through direct contact with pigs or the food chain is a possibility,” they state in their study report. Scientists from NIH’s National Institute of Allergy and Infectious Diseases (NIAID) conducted the work at Rocky Mountain Laboratories in Hamilton, Montana.
Scientists first identified RESTV in 1989 in research monkeys shipped from the Philippines to Reston, Virginia. The virus also gained attention in 2008 when an outbreak swept through pigs in the Philippines. That outbreak led to the first association of pig-to-human RESTV transmission, prompting the World Health Organization to issue a global alert in February 2009. RESTV sequences also have been identified in pigs in China, and the scientists suggest officials monitor pigs for disease throughout the Philippines and Southeast Asia.
The NIAID scientists conducted their study to answer two key questions: could they cause disease in young pigs—mimicking natural infection with RESTV isolated from the 2008 swine outbreak — and if so, would those pigs shed virus through their respiratory tract? Their work confirmed that in fact the pigs developed severe pneumonia with virus shedding from the upper respiratory tract. They also determined that the age of the piglets at the time of infection—they used animals between three and seven weeks old—did not change the course of disease. Their work involved Yorkshire cross-bred pigs, which frequently are used in commercial pig production systems. RESTV has not been found in commercial pigs in the United States.
Continued studies in this project will examine whether co-infection with other swine viruses affects the ability of RESTV to cause severe disease in pigs and whether pigs have a broad role in hosting ebolaviruses.
Article
E Haddock et al. Reston virus causes severe respiratory disease in young domestic pigs. PNAS DOI: 10.1073/pnas.2015657118 (2020).
