Using the SASS® Air Sampler for Viral Monitoring (Avian Influenza)
Viral disease outbreaks are appearing worldwide that could trigger the next pandemic, and epidemiologists assert that the occurrence of such an event is not a question of “if”, but “when.” Models of communicable disease propagation have shown that early warning and containment can significantly reduce the risk of small outbreaks spreading into the general population (1). However, this can only occur if the pathogen is detected early in its infectious cycle. Existing monitoring initiatives are based on blood and/or swab samples. This is a very direct and conclusive approach, but has obvious limitations from cost and sampling statistic perspectives. With the global character of human travel and food distribution, it is highly likely that diseased individuals, livestock, or produce will slip through such a sparse safety net.
A new viral monitoring strategy pioneered by the University of California, Davis, provides the opportunity to more thoroughly monitor at a decreased cost (2). Dr. Sharon Hietala and her associates use a portable aerosol collection system manufactured by Research International to collect virus-contaminated particles from the air, followed by identification with highly sensitive nucleic acid techniques. They have shown that this approach allows large areas to be effectively monitored at low cost, with minimal intrusion and controversy.
- Ira M. Longini Jr, et al., Science, 309, 1083 (2005).
- Sharon K. Hietala, et al., J. Vet. Diagn. Invest., 17, 198 (2005). Printed with permission of AAVLD, May 6, 2009.
The SASS 2300 air sampler is built upon the same technology as the SASS® 2000 Plus air sampler which has been designated and certified as an “Approved Product for Homeland Security” under the Support Anti-Terrorism by Fostering Effective Technologies Act of 2002 (the SAFETY Act). Worldwide, only six products for chemical and biological agent collection and detection have succeeded in winning this level of government approval.
Field Collection of Viral Biohazards - Presention in PDF format about the capabilities of Research International's SASS air samplers.View PDF version
The National Strategy for Pandemic Influenza guides our preparedness and response to an influenza pandemic, with the intent of (1) stopping, slowing or otherwise limiting the spread of a pandemic to the United States; (2) limiting the domestic spread of a pandemic, and mitigating disease, suffering and death; and (3) sustaining infrastructure and mitigating impact to the economy and the functioning of society.
The Strategy will provide a framework for future U.S. Government planning efforts that is consistent with The National Security Strategy and the National Strategy for Homeland Security. It recognizes that preparing for and responding to a pandemic cannot be viewed as a purely federal responsibility, and that the nation must have a system of plans at all levels of government and in all sectors outside of government that can be integrated to address the pandemic threat. Read the full report HERE>>
Key Facts About Avian Influenza (Bird Flu) and Avian Influenza A (H5N1) Virus
Avian influenza in birds
Avian influenza is an infection caused by avian (bird) influenza (flu) viruses. These influenza viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, avian influenza is very contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and kill them.
Infected birds shed influenza virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated secretions or excretions or with surfaces that are contaminated with secretions or excretions from infected birds. Domesticated birds may become infected with avian influenza virus through direct contact with infected waterfowl or other infected poultry, or through contact with surfaces (such as dirt or cages) or materials (such as water or feed) that have been contaminated with the virus.
Infection with avian influenza viruses in domestic poultry causes two main forms of disease that are distinguished by low and high extremes of virulence. The "low pathogenic" form may go undetected and usually causes only mild symptoms (such as ruffled feathers and a drop in egg production). However, the "highly pathogenic" form spreads more rapidly through flocks of poultry. This form may cause disease that affects multiple internal organs and has a mortality rate that can reach 90-100% often within 48 hours.
Pictured: The influenza virus, as well as the antigens (small spikes) on the viral particle surface. These antigens are what stimulate the immunological response in the host (bird, human, etc.)
Human infection with avian influenza viruses
There are many different subtypes of type A influenza viruses. These subtypes differ because of changes in certain proteins on the surface of the influenza A virus (hemagglutinin [HA] and neuraminidase [NA] proteins). There are 16 known HA subtypes and 9 known NA subtypes of influenza A viruses. Many different combinations of HA and NA proteins are possible. Each combination represents a different subtype. All known subtypes of influenza A viruses can be found in birds.
Usually, "avian influenza virus" refers to influenza A viruses found chiefly in birds, but infections with these viruses can occur in humans. The risk from avian influenza is generally low to most people, because the viruses do not usually infect humans. However, confirmed cases of human infection from several subtypes of avian influenza infection have been reported since 1997. Most cases of avian influenza infection in humans have resulted from contact with infected poultry (e.g., domesticated chicken, ducks, and turkeys) or surfaces contaminated with secretion/excretions from infected birds. The spread of avian influenza viruses from one ill person to another has been reported very rarely, and transmission has not been observed to continue beyond one person.
"Human influenza virus" usually refers to those subtypes that spread widely among humans. There are only three known A subtypes of influenza viruses (H1N1, H1N2, and H3N2) currently circulating among humans. It is likely that some genetic parts of current human influenza A viruses came from birds originally. Influenza A viruses are constantly changing, and they might adapt over time to infect and spread among humans.
During an outbreak of avian influenza among poultry, there is a possible risk to people who have contact with infected birds or surfaces that have been contaminated with secretions or excretions from infected birds.
Symptoms of avian influenza in humans have ranged from typical human influenza-like symptoms (e.g., fever, cough, sore throat, and muscle aches) to eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications. The symptoms of avian influenza may depend on which virus caused the infection.
Studies done in laboratories suggest that some of the prescription medicines approved in the United States for human influenza viruses should work in treating avian influenza infection in humans. However, influenza viruses can become resistant to these drugs, so these medications may not always work. Additional studies are needed to d emonstrate the effectiveness of these medicines.
Avian Influenza A (H5N1)
Influenza A (H5N1) virus, also called H5N1 virus is an influenza A virus subtype that occurs mainly in birds, is highly contagious among birds, and can be deadly to them. H5N1 virus does not usually infect people, but infections with these viruses have occurred in humans. Most of these cases have resulted from people having direct or close contact with H5N1-infected poultry or H5N1-contaminated surfaces.
Human health risks during the H5N1 outbreak
Of the few avian influenza viruses that have crossed the species barrier to infect humans, H5N1 has caused the largest number of detected cases of severe disease and death in humans. In the current outbreaks in Asia and Europe more than half of those infected with the virus have died. Most cases have occurred in previously healthy children and young adults. However, it is possible that the only cases currently being reported are those in the most severely ill people, and that the full range of illness caused by the H5N1 virus has not yet been defined. For the most current information about avian influenza and cumulative case numbers, see the World Health Organization (WHO) avian influenza website.
So far, the spread of H5N1 virus from person to person has been limited and has not continued beyond one person. Nonetheless, because all influenza viruses have the ability to change, scientists are concerned that H5N1 virus one day could be able to infect humans and spread easily from one person to another. Because these viruses do not commonly infect humans, there is little or no immune protection against them in the human population. If H5N1 virus were to gain the capacity to spread easily from person to person, an influenza pandemic (worldwide outbreak of disease) could begin. For more information about influenza pandemics, see PandemicFlu.gov.
No one can predict when a pandemic might occur. However, experts from around the world are watching the H5N1 situation in Asia and Europe very closely and are preparing for the possibility that the virus may begin to spread more easily and widely from person to person.
Treatment and vaccination for H5N1 virus in humans
The H5N1 virus that has caused human illness and death in Asia is resistant to amantadine and rimantadine, two antiviral medications commonly used for influenza. Two other antiviral medications, oseltamavir and zanamavir, would probably work to treat influenza caused by H5N1 virus, but additional studies still need to be done to demonstrate their effectiveness.
There currently is no commercially available vaccine to protect humans against H5N1 virus that is being seen in Asia and Europe. However, vaccine development efforts are taking place. Research studies to test a vaccine to protect humans against H5N1 virus began in April 2005, and a series of clinical trials is under way. For more information about H5N1 vaccine development process, visit the National Institutes of Health website.
Potential Human Impact
LPAI viruses have the ability to mutate into HPAI strains that can infect humans. These strains of HPAI are the source of pandemic outbreaks where a new subtype of the virus is created and can be transmitted between humans or an older subtype of the virus resurfaces that hasn't been detected or transmitted for years. Influenza pandemics in the past have caused severe illness and death in humans and substantial economic loss.
More Links on Avian Influenza:
U.S. Department of Agriculture Pandemic Flu
Centers for Disease Control and Prevention
Animal and Plant Health Inspection Service (APHIS)- Hot Issues-Avian Influenza
World Organization for Animal Health (OIE)
World Health Organization Avian Influenza web site
APHIS-Biosecurity for the Birds