US Using Monkeypox As Surrogate/Model For Smallpox
From Patricia Doyle, PhD
Monkeypox has been the focus of research for many years. In 2000, CSIRO in Australia, added the IL 4 gene to monkeypox and found that this action caused monkeypox to become "weaponized" with a 100% kill rate. CSIRO scientists claimed that the purpose of the experiment was to alter monkeypox for use as rodent birth control. Although the experiment was not successful in as much as rodent birth control, the scientists still submitted the "unexpected" result a"blueprint" for weaponzied poxivirus to medical journals for all to see.
Ft. Detrick, as well as other US government and private labs have also been researching monkeypox.
I do hope that more information will be forthcoming about the true origin of the US monkeypox outbreak. Once that a pathogen has emerged, it is very difficult to contain an outbreak and to ensure that the pathogen does not become ingrained and endemic. I think that it is going to be very difficult, if not impossible, to purge the US of Monkeypox. We did not do well with other diseases, such as West Nile Virus, HantaVirus especially Sin Nombre, SARS etc.
The following website, asmbiodefense.org/tuepos.asp has many biodefense research article/abstracts, even including work on the 1918 influenza.
IV Cidofovir Treatment of Smallpox and Monkeypox in the Cynomolgus Monkey Model
J. W. Huggins, S. H. Zwiers, R. O. Baker, L. E. Hensley, T. Larsen, M. J. Martinez, P. J. Jahrling; USAMRIID, Fort Detrick, MD.
IV Cidofovir (approved for treatment of cytomegalovirus retinitis in AIDS patients) is available for contingency use to treat cases of smallpox under IND,s held by both DHHS and DoD. Evidence supporting IND use is the ability of cidofovir to inhibit Variola (smallpox) and other orthopoxviruses in vitro and to treat mice lethally infected with cowpox by either the intranasal or aerosol routes. Aerosol infection of cynomolgus monkeys with monkeypox produced a lethal fibrinonecrotic bronchopneumonia, which could be treated with cidofovir by using a treatment regimen that mimicked human treatment. To determine if a lesional model could be successfully treated, we used the uniformly lethal intravenous monkeypox model to show that cidofovir prophylaxis provided complete protection, showed no signs of illness, and controlled viral replication as measured in blood, while the placebo-treated animal had >850 lesions and blood viral titers, measured by quantitative real-time TAQMAN®-MGB PCR, first detectable on day 3, rising to 107 genomes/ml by day 9 and remaining at high levels until the primate was enthanized moribund on day 12. Similar studies of intravenous infection with 108 PFU of the Harper strain of Variola produced a similar disease with > 250 lesions (WHO category "grave) and 33% mortality (day 11), but increasing the viral challenge dose 10-fold resulted in a 100% acutely lethal disease (mean time to death 4 days) that more closely mimicked hemorrhagic smallpox, with viral levels in organs 1,000- to 10,000-fold greater than with 108 PFU. Prophylaxis with IV cidofovir resulted in protection from lethal disease, with significant reductions of blood viral levels and lesion counts. We believe the lesional model of smallpox produced by 108 PFU of Harper strain is the most appropriate primate model for drug evaluation.
Real-Time TAQMAN®-MGB PCR Assay of Smallpox, Monkeypox, and Cowpox Genomes in Blood and Tissues from Experimentally Infected Animals
S. H. Zwiers, D. Miller, R. O. Baker, D. Kulesh, P. B. Jahrling, J. W. Huggins; USAMRIID, Fort Detrick, MD.
Following the level of virus in blood can be a useful tool in disease management, especially in monitoring the success of antiviral therapy. Primate models of smallpox and monkeypox have provided specimens appropriate for validating methodology and determining if viral burden, as reflected by virus levels in blood, are useful in monitoring successful experimental antiviral therapy with IV cidofovir. Blood of experimentally infected primates was extracted with the Qiagen QIAamp DNA Mini Kit. Incubating blood or tissues in AL buffer plus Proteinase K for > 1 h at 56°C completely inactivated Variola (the virus that causes smallpox) and monkeypox. Consequently, 4 h incubation was adopted as adequate to safely remove Variola-infected samples from biocontainment. Quantitative TAQMAN®-MGB PCR with a pan-orthopox primer/probe set directed against the viral hemagglutinin gene allowed us to evaluate virus levels of 1000 gene copies per ml of whole blood or gram of tissue. Virus levels in blood of cynomolgus monkeys experimentally infected with Variola and monkeypox were significantly reduced in monkeys successfully treated with cidofovir compared with levels in controls (placebo: monkeypox > 107 and Variola > 5 x 108 genomes/ml). To understand how the level of virus in blood correlates with virus levels in tissues, we used the uniformly lethal intranasal infected cowpox mouse model as a surrogate to correlate virus in blood and tissues throughout the course of this lethal infection. Virus was first detectable in blood at 48 h after infection and peaked at greater than 105 genomes per ml by day 5 postinfection. Near real-time monitoring of virus levels in blood may allow for rapid evaluation of the efficacy of antiviral therapy during an initial smallpox outbreak.
Also, Ken Alibek's research:
Cytokine-mediated Control of Poxvirus Infection
G. Liu1, Q. Zhai1, T. G. Voss2, M. Maland3, A. Wu1, J. Wells4, D. Schaffner1, E. Grene1, T. Robinson1, C. L. Bailey1,5, K. Alibek1,5; 1Advanced Biosystems, Inc., Manassas, VA, 2Southern Research Institute, Frederick, MD, 3Southern Research Institute, Drederick, MD, 4Southern Research Institue, Frederick, MD, 5George Mason University, Manassas, VA.
Background: Certain cytokines, particularly interferons (IFN), are well known for their antiviral effects in various virus infections. In this report, we demonstrate that IL-15, IFN-â and -ã are capable of enhancing the extrinsic antiviral activity of cultured murine macrophage cells. Furthermore, we have adapted a mouse respiratory vaccinia infection model to evaluate the in vivo antiviral effects of cytokines. Methods: RAW 264.7 cells were activated with individual cytokines and then co-cultured with vaccinia virus-infected human 293 cells overnight. The virus titers in the cocultures were measured by plaque assay. Balb/c mice were infected intranasally with 8 X LD50 of vaccinia virus (strain WR). Murine cytokines were administered intranasally for 5 consecutive days, starting one day before the infection. The animals were observed for signs of sickness and death for 21 days. Results: Our results indicate that IL-15, IFN-â and -ã are capable of inducing the inhibition of virus replication in by-stander cells. Intranasal administration of recombinant murine IFN-á and IFN-ã resulted in animal survival rates of 100 and 95%, respectively. In contrast, no mice in untreated control (placebo) survived the lethal vaccinia challenge. The organ virus titers in treated mice were 100,000-fold lower than that in placebo. IL-15 provided slight protection (10% survival). Both innate and adaptive host immune responses are likely to play significant roles in the IFN-mediated control of poxvirus replication in mice. Conclusions: Intranasal administration of IFN-á and IFN-ã provides nearly full protection against respiratory vaccinia virus infection in mice; therefore, our results have implications in the utilization of interferon as a prophylactic tool on a scenario of aerosol orthopoxvirus infection.
June 13, 2003 Previous
Monkeypox in the news
Scientists at US agencies have been using virus as surrogate and model for smallpox | By Peg Brickley
Long before it became the topic of hourly news bulletins, monkeypox was a virus of interest to US researchers intent on creating safer smallpox vaccines and treatments. Some hope now that monkeypox's Western Hemisphere debut will spread the wealth of scientific knowledge back to central and western Africa, where monkeypox is endemic and sometimes fatal.
"Monkeypox has not been established as a top-priority disease, and it should be," said Joel Breman, who chaired the World Health Organization's monkeypox study committee and is now senior scientist at the National Institute of Health's John E. Fogarty International Center. "It should be a higher priority because of its potential for exportation, number one, and number two, because the natural history of monkeypox remains unknown even 30 years after its discovery in humans and 45 years from its first discovery in nonhuman primates."
Labs at the US Army Research Institute for Infectious Diseases (USAMRIID) and at the National Institutes of Health (NIH) labs in Maryland use monkeypox as a substitute for smallpox because it is easier to handle in the laboratory and less likely to spread among humans.
"Our main goal has been to look at therapeutics. We use monkeypox because it is a BSL-3 [biosafety level 3] agent so we can use it under slightly less strict conditions in the lab," said Robert Baker, a USAMRIID virologist.
Science and logistics make monkeypox a good surrogate for the more lethal pox. "Monkeypox produces a disease in monkeys and people that is essentially identical to smallpox," Baker told The Scientist.
Animal models created at USAMRIID are being used to test therapeutics against smallpox, such as the antiviral cidofovir as well as safer versions of the smallpox vaccine, such as the modified vaccinia Ankara (MVA) vaccine, that potentially pose less of a threat to immunocompromised people.
"There are whole groups of people contraindicated for vaccination," Baker said. "One of our goals is to find an option for people who shouldn't be taking the vaccine. In addition, we are trying to extend the window of protection so we can treat post-exposure."
In collaboration with Donald Smee, research professor at Utah State University's Institute for Antiviral Research, Army scientists are developing rodent models to replace the more expensive primate test subjects for monkeypox. Monkeypox's importation to this country, probably by way of a giant Gambian rat, was "a total surprise," Smee, who has published extensively on monkeypox, told The Scientist. And no, Baker said, prairie dogs were never on the list of candidates to serve as rodent models. Cotton rats show the most promise, Baker said.
Bernard Moss, chief of the viral disease laboratory at NIH, is evaluating highly attenuated MVA against primates infected with monkeypox at USAMRIID. Ongoing work is also looking at recombinant proteins, Moss said, and he expects to report results before the end of the year.
"The top priority is to control and mute this epidemic so there aren't more cases," Breman told The Scientist. "This is a huge opportunity both to look at treatments and possibly prevention, to look at how the disease will be acquired and spread in an environment where you can actually do surveillance properly."
Links for this article
J.G Breman, D.A. Henderson, "Poxvirus dilemmas"monkeypox, smallpox, and biologic terrorism," New England Journal of Medicine, 339:556-559, August 20, 1998.
Technical Advisory Group on Human Monkeypox
John E. Fogarty International Center
US Army Research Institute for Infectious Diseases
Utah State University Institute for Antiviral Research
D.F. Smee et al., "Characterization of wild-type and cidofovir-resistant strains of camelpox, cowpox, monkeypox, and vaccinia viruses." Antimicrobial Agents and Chemotherapy, 46:1329-1335, May 2002.
©2003, The Scientist Inc. in association with BioMed Central
Patricia A. Doyle, PhD
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