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Office of the Director, National Vaccine Program Office
Laboratory Containment of Wild Polioviruses
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Office of the Director, National Vaccine Program Office Laboratory Containment of Wild Polioviruses Home | Submit Results | Support |
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WHO Global Action Plan for Laboratory Containment of Wild Polioviruses CONTENTS
[ To Top ] To provide a systematic global plan of action to minimize the risk of reintroduction of wild polioviruses from the laboratory into the community. [ To Top ] The world will be declared polio-free when the World Health Organization (WHO) Global Commission for the Certification of the Eradication of Poliomyelitis (GCC) is satisfied that all Regions have documented the absence of wild poliovirus transmission for at least 3 consecutive years and that laboratories identified with wild poliovirus materials have implemented appropriate containment conditions.1 The probability of wild poliovirus transmission from the laboratory to the community is small, but the consequences grow greater as polio-free countries increase in number and immunization decreases or stops. Safe handling and, ultimately, appropriate laboratory containment of wild poliovirus infectious and potential infectious materials is crucial. The first edition of the Global Action Plan for Laboratory Containment of Wild Polioviruses was published by WHO in December 1999. The Plan was based on broad input from biosafety experts, epidemiologists, laboratory scientists, ministries of health of all nations, and vaccine manufacturers. This second edition of the Global Action Plan replaces the first. It incorporates lessons learned from biomedical laboratory surveys and inventories in more than a hundred nations in five of the six WHO Regions. It expands previous recommendations to include vaccinederived polioviruses (VDPV). It defines biosafety requirements in terms of risks. It describes two phases of activities leading to containment: the Laboratory Survey and Inventory Phase and the Global Certification Phase. Finally, it examines the implications of future global immunization policy decisions on containment in the Post Global Certification Phase. Laboratory Survey and Inventory This phase covers the period when the numbers of polio-free countries and Regions are increasing, but wild polioviruses continue to circulate somewhere in the world. During this phase, nations:
Global Certification This phase begins when one year has elapsed without isolation of wild poliovirus anywhere in the world. During this phase nations:
Post Global Certification The global certification containment requirements are anticipated to remain in force with concurrent immunization policies. At sometime in the future, international advisory bodies are expected to re-examine post certification immunization policies in light of current research outcomes, national experiences, and assurances that surveillance, vaccine stockpiles, and emergency response plans are adequate should polio re-emerge. If universal polio immunization is discontinued, containment requirements for wild as well as OPV viruses are likely to become more stringent than outlined in this document, consistent with the consequences of inadvertent transmission of poliovirus from the laboratory to an increasingly non-immune community. Publication of the plan This document provides the background, rationale, and strategy to ensure that laboratory facilities and biosafety practices are consistent with the risk of inadvertent transmission of poliovirus to the community. Full cooperation and commitment at all levels are essential to ensure that polio will not be a threat to future generations. [ To Top ] Polio, or poliomyelitis, is an infectious disease caused by poliovirus, a member of the genus Enterovirus. There are three serotypes of poliovirus: 1, 2, and 3. Susceptible human cells have a specific protein receptor to which poliovirus may attach and thereby enter. The virus infects cells of the oropharynx, the tonsils, the lymph nodes of the neck, and the small intestines. Infection progresses through cycles of virus replication. Once infection is established in the gastrointestinal tract, poliovirus can invade the central nervous system (CNS) by penetrating the blood/brain barrier or by spreading along nerve fibres. When non-immune persons are infected with poliovirus, the outcome may vary from unapparent infection without symptoms to mild illness, aseptic meningitis, or paralytic poliomyelitis.2 About 1% of infections result in recognized neurological illness. The incubation period is 4-35 days, typically 7-14 days. Initial clinical symptoms may include fever, fatigue, headache, vomiting, constipation, stiffness in the neck, and pain in the limbs. The virus multiplies and destroys motor neurons, which may result in a permanent paralysis of muscles activated by the affected nerves. Poliovirus is transmitted from person to person either through droplets from the upper respiratory tract during the early days of infection or, more commonly, through ingestion of infectious faecal material in low hygiene situations.3 Following infection, poliovirus can be found in the oropharynx for one to two weeks, in the blood for about one week, and in faeces for one to two months, even in individuals without symptoms of disease. On autopsy of persons who have died of the disease, poliovirus has been recovered from faeces, intestinal contents, lymph nodes, brain tissue, and spinal cord tissue. Less than 1% of infections result in poliomyelitis. Many "healthy" children shed virus during periods of high prevalence. Poliovirus in the environment is the direct result of recent poliovirus infections in the human community. Contamination of soil occurs through human defecation near dwellings, crop fertilization with untreated or inadequately treated night soil or sewage, and recycled wastewater for irrigation. Presence of poliovirus in sewage reflects the prevalence of infection in the community. Contamination of surface waters may occur through discharge of untreated or inadequately treated sewage or run off from contaminated soil. Humans are the only natural reservoirs of poliovirus. Higher non-human primates (chimpanzees and gorillas) are susceptible to infection and disease, but these populations are not sufficiently large to sustain poliovirus transmission in the absence of human infections.4 Poliovirus is resistant to inactivation by common laboratory disinfectants such as alcohol and cresols. The virus is rapidly destroyed by exposure to temperatures of 50OC or greater, autoclaving, or incineration.2 It is readily inactivated by dilute solutions of formaldehyde or free residual chlorine, ultraviolet light, heat and drying. Inactivation is slowed by the presence of extraneous organic matter. Under stable laboratory conditions poliovirus in clinical or environmental specimens may survive at freezing temperatures for many years, under refrigeration for many months, and at room temperatures for days to weeks.2 Rates of poliovirus inactivation in nature are greatly influenced by the immediate environment. Poliovirus infectivity has been estimated to decrease by 90% in soil every 20 days in winter and every 1.5 days in summer. A similar estimated 90% decrease at ambient temperatures occurs in sewage every 26 days, in freshwater every 5.5 days, and in seawater every 2.5 days.4 Protective immunity against poliomyelitis is conferred through immunization or natural poliovirus infection. Immunity is poliovirus serotype-specific. Protection against disease is associated with antibodies that circulate in the blood stream and prevent spread of the virus to the central nervous system. Protection against infection is associated with both circulating antibodies in the blood and secretory antibodies in the gut and upper respiratory tract.5 Both live attenuated oral polio vaccine (OPV) and the injectable inactivated polio vaccine (IPV) protect against paralytic poliomyelitis.6, 7 However, neither vaccine provides absolute protection against infection or reinfection with the virus itself. IPV stimulates protective antibodies in the blood (i.e. circulatory immunity) that stops poliovirus in the gut from entering and replicating in CNS. IPV effectively prevents virus spread and controls polio in countries with good hygiene.7 OPV, a live virus that replicates in the gut, additionally induces mucosal immunity that inhibits intestinal virus replication. The resulting reduction in faecal shedding is associated with decreased transmission to other persons, making the choice of OPV critical for the global polio eradication initiative. However, the live OPV has been associated with vaccine associated paralytic poliomyelitis (VAPP) on the order of one in every 2.5 million doses administered.7 In infrequent cases, with about a dozen identified worldwide, immunocompromised patients with B-cell deficiencies may continue to shed vaccine virus for extended periods, leading over time to an accumulation of genetic changes in the excreted virus.8 Continuous person-to-person circulation of vaccine polioviruses over extended periods of time in poorly immunized populations may result in genetic changes where neurovirulence and transmissibility profiles are characteristic of wild poliovirus.9 Such viruses pose risks similar to naturally occurring polioviruses. Interruption of wild poliovirus transmission Polio occurred worldwide prior to the advent of immunization in the mid-1950s. Immunization has been highly effective in reducing the number of cases worldwide.10 Further reduction in highly endemic areas has been achieved through improved routine childhood immunization and the strategic use of OPV in the polio eradication initiative.11 The interruption of wild poliovirus transmission is based on the assumption that wild poliovirus circulation will cease when it is deprived of its susceptible human host through immunization.12 The continued decrease in the incidence of polio in many countries and the progressive disappearance of poliovirus genetic lineages suggest that the interruption of human-to-human transmission is achievable. [ To Top ] Less than one year after smallpox was eradicated in 1977, two cases occurred in the United Kingdom, both linked to a smallpox laboratory. The index case worked in a room located directly above the laboratory. Two persons died; the index patient as a result of infection, and the director of the laboratory, who took his own life because of the accident.13 When polio is eradicated every effort must be made to ensure that wild poliovirus is not similarly transmitted from the laboratory to an increasingly non-immune community. In theory, polioviruses may be transmitted to persons outside the laboratory through contaminated laboratory effluents released into sewage, solid wastes transported to landfills, spent air exhausted to surroundings, or through contaminated workers’ skin or clothing. However, transmission through such routes is extremely difficult to document against a background of high levels of immunity acquired through natural infection or immunization. More readily documented are poliovirus infections of laboratory workers with potential for transmission to the community. From 1941 to 1976 a total of 12 laboratory-associated poliomyelitis cases, including two deaths, were recorded.14-17 Accounts of 7 of the 12 were unpublished. Most cases occurred in the pre-vaccine era and before the advent of cell culture. The first report of a laboratory-associated infection, published in 1941, described a case of poliomyelitis most likely acquired through washing and grinding infected tissues in preparation for inoculation into monkeys.18 Two years later, two laboratory workers were infected with the prototype Lansing (Armstrong) strain while attempting to infect mice.19 Two additional reported cases of poliomyelitis in laboratory workers were fatal: one in the United States20 and the second in South Africa.21 The paucity of reports of laboratory-associated poliomyelitis since vaccines were introduced testifies to the effectiveness of vaccines and vastly improved laboratory facilities, technologies, and procedures.22, 23 Nevertheless, recent evidence indicates that the potential remains for transmission of poliovirus from the laboratory to the community. In 1992, a wild-type 1 strain used for IPV production was documented as being transmitted from a worker in a vaccine production facility to his young son.24 In another incident, a child was reported infected with a prototype strain of type 3 commonly used in laboratories for research and IPV vaccine production. The source of this infection was not determined. IPV is highly effective in preventing disease, but its use cannot be assumed to prevent silent infection among laboratory workers. OPV provides a more effective barrier but silent infections may still occur. The incidence of poliovirus infections without clinical symptoms among laboratory workers is unknown. In the absence of fully effective vaccines, appropriate biosafety measures are crucial to prevent poliovirus infection of laboratory workers and subsequent transmission. Absolute containment cannot be assured. Questions of intentional or unintentional non-compliance will always remain. But effective containment, that is, reducing the risk of inadvertent reintroduction of wild poliovirus into the community, is a realistic goal.25 [ To Top ] Polioviruses (Box 1) Polioviruses are defined by standard neutralization tests with specific antisera. The three poliovirus serotypes form a unique genetic group of human enteroviruses that initiate infection by binding to a specific cellular receptor (PVR:CD155). Other enteroviruses may occasionally be associated with cases of acute flaccid paralysis, but they are not polioviruses and they do not bind to PVR. Wild polioviruses have the capacity to circulate indefinitely within susceptible human populations. Molecular studies have shown that the capsid sequence lineages of wild polioviruses are maintained along chains of transmission, while the noncapsid and noncoding sequences may be exchanged by recombination with other enteroviruses during circulation. Thus, the identification of sequences outside of the capsid region as "poliovirus" may be arbitrary. OPV strains have been demonstrated by clinical studies to be significantly less neurovirulent than wild poliovirus and thus pose greatly reduced risks when administered to vaccinees. Candidate attenuated vaccine strains that have not undergone extensive field testing and have not been approved by national regulatory authorities for use in oral polio vaccines are regarded as wild polioviruses for purposes of containment. Genetic mutations occur in all circulating polioviruses. Mutations in the VP1 region provide the basis for differentiating wild poliovirus isolates into genotypes and lineages. Mutations further characterize isolates of OPV origin. A difference in the range of 0-1% from the parent OPV strain by sequence homology of the full VP1 region is consistent with normal virus shedding or limited person-to-person spread. A difference in the range of 1-15% is characteristic of isolates from OPV-derived polio outbreaks, consistent with extensive transmission and the capacity to cause paralytic disease.9
Materials are further categorized as wild poliovirus infectious or potential wild poliovirus infectious. Included in both of these categories are clinical and environmental materials and laboratory products of these materials. For purposes of containment, VDPV is considered wild. Wild poliovirus infectious materials (Box 2) Wild poliovirus (including VDPV) may be present in a variety of clinical materials, most commonly in faeces and throat specimens, less commonly in blood, and rarely in cerebrospinal fluids in non-paralytic and paralytic infections. In fatal infections, wild poliovirus may be present in faeces, intestinal contents, lymph nodes, brain tissue, and spinal cord tissue.25 Poliovirus may be found in blood during the first week of infection, before neutralizing antibodies appear, but is rarely found in blood after onset of clinical signs of central nervous system involvement. All such clinical materials from persons with acute poliomyelitis are defined as infectious, even though the presence of virus may not have been confirmed. Wild polioviruses present in environmental samples, such as sewage and water, reflect the presence of poliovirus in the community. The viral content of sewage may vary widely, depending on many environmental factors. Infectious laboratory products include infected cell cultures, virus stocks, research materials where wild poliovirus has been used, and infected non-human primates and transgenic mice.26
Potential wild poliovirus infectious materials (Box 3) At least 99% of wild poliovirus infections cause no recognizable paralytic disease, but may result in significant numbers of wild polioviruses being shed in faeces and respiratory secretions. Wild poliovirus isolation rates of 8-19% have been reported from stools of healthy children during polio seasons in endemic areas.27,28 Laboratories with stored collections of faecal, throat, or environmental samples should assess the likelihood of the presence of wild polioviruses in these materials, based on sample treatment and storage history, the country of origin, the year, and the time of the last indigenous wild poliovirus isolates in that country (see Annex 1). Uncharacterised enterovirus-like cell culture isolates or undifferentiated poliovirus isolates from such materials are included as potential wild poliovirus infectious materials until proven otherwise.29 Frozen stool samples from young children during endemic periods are likely to have the highest levels of infectious wild polioviruses.
Serum samples and cerebrospinal fluids collected in polio endemic areas for other purposes are not considered as potential wild poliovirus infectious materials because of the low probability of infectious poliovirus being present. Clinical or environmental materials stored without refrigeration for three months or more, refrigerated for one year or more, heat inactivated, treated with disinfectants known to inactivate polioviruses, or tested and found negative for the presence of enteroviruses are not considered infectious or potentially infectious for wild poliovirus. [ To Top ] LABORATORY SURVEY AND INVENTORY This phase covers the period when the numbers of polio-free countries and regions are increasing but wild polioviruses continue to circulate somewhere in the world. During this phase, nations:
National, regional, and global inventories of all institutions/ laboratories with stored stocks of wild poliovirus infectious or potential infectious materials provide the basis for achieving global laboratory containment when wild poliovirus transmission is interrupted. The four primary activities of this phase are described below. The purpose of the national survey is to identify all laboratories storing wild poliovirus infectious or potential infectious materials. A major function of the survey is to encourage destruction of those materials that are no longer needed. The national survey is hierarchical, beginning with notification to the national government by WHO and proceeding through Ministries of Health and other concerned Ministries to agencies and institutions, and to individual laboratories. Because many laboratories that might possess such materials are outside the health sector, completion of the national survey requires Ministries of Health to enlist the cooperation of other ministries, such as Education, Defence, and Environment Box 4. Each country should designate a National Task Force/Coordinator for planning and implementing the multi-sectoral national survey and for verifying that all activities have been completed. Many different types of laboratories may store wild poliovirus infectious or potential infectious materials. A variety of resources may be required to identify these laboratories, including national laboratory registries, accrediting bodies, professional organizations, and national and institutional biosafety networks. Types of laboratories possibly storing wild poliovirus infectious materials are described below and summarized in Box 4.
Laboratories storing potential wild poliovirus infectious materials are more challenging to identify. These materials may include a variety of clinical or environmental samples collected for purposes unrelated to polio investigations. An example is a laboratory with faecal samples collected for diarrhoeal disease research during a time and in a geographical area of wild poliovirus endemicity. All of the above-listed laboratories may have potential wild poliovirus infectious materials. Others include clinical bacteriology, parasitology, pathology, gastroenterology, and nutrition laboratories, which are likely to be located in hospitals (both private and government), academic institutions, and the private sector. Research laboratories studying enteric diseases, cholera, parasitic infections, or nutrition are of particular importance (Box 4).
Each laboratory should conduct a thorough search for materials that meet the definition of wild poliovirus infectious or potential infectious materials. Laboratories should critically examine the need to retain any wild poliovirus materials and dispose of all such materials that serve no programmatic or research purpose. For most diagnostic tests, wild polioviruses may be replaced with OPV strains, inactivated antigens, or non-polio enteroviruses (Annex 2). If wild poliovirus materials are required, only viruses readily identifiable by molecular methods should be used. Laboratories retaining wild poliovirus infectious or potential infectious materials should be listed on the National Inventory and operate under Biosafety Level-2/polio (BSL- 2/polio) conditions as described below. 2. Developing National Inventories The purpose of the National Inventory is to document the location of the laboratory and types of wild poliovirus infectious or potential infectious materials being retained in the country, meet the country requirements for certification of Regions as polio-free, and maintain a current list of laboratories to be notified to initiate the appropriate containment procedures one year after detection of the last wild poliovirus. The National Inventory is an active record maintained by the national government and updated regularly to prepare for the post global eradication phase. The National Inventory and supporting documents are prepared and presented to the National Certification Committee for review, endorsement, and submission to the Regional Certification Commission as a component of National Documentation for Certification of Polio Eradication. National Inventories of laboratories with wild poliovirus infectious or potential infectious materials are compiled into Regional Inventories maintained by the WHO Regional Offices. Inventories from all six Regions constitute the Global Inventory maintained by WHO, Geneva, Switzerland. 3. Implementing Biosafety Level 2/polio Laboratories listed on National Inventories as retaining wild poliovirus infectious or potential infectious materials should operate under Biosafety Level 2/polio (BSL-2/polio) conditions. The purpose of the BSL-2/polio requirement is to reduce the risk of reintroducing wild polioviruses from the laboratory into the community at a time when poliovirus circulation is decreasing or no longer occurring in many areas of the world. The designation BSL-2/polio refers to standard BSL-2 conditions in addition to specific requirements for wild polioviruses. BSL-2 is defined as good microbiological practices in an appropriately equipped basic microbiology laboratory. Specific requirements are described in the 2002 WHO Laboratory Biosafety Manual (3rd edition).30 In brief, BSL-2 includes safe laboratory practices, appropriate disinfection, sterilization, and waste disposal procedures, and the availability and use of equipment designed to reduce or eliminate hazards. The basic microbiology laboratory consists of a facility with an autoclave on site and a certified class I or II biological safety cabinet or equivalent containment device for all manipulations with open infectious materials. A mechanical room ventilation system with inward directional airflow is desirable. BSL-2/polio includes the following precautions specific for laboratories with wild poliovirus materials:
BSL-2/polio requirements are summarized in Box 5 and described in more detail in Annex 3.
4. Preparing for the Post Global Eradication Phase Countries should establish channels for regular communications with laboratories on the National Inventory to periodically inform them of progress toward interruption of wild poliovirus transmission, the need to maintain updated inventories, and modifications in biosafety recommendations. The channels will be used later to notify laboratories of the effective date to implement appropriate biosafety measures. Countries electing to retain wild poliovirus infectious and potential infectious materials should begin now to ensure that the designated laboratories meet the appropriate biosafety requirements for facilities and staff training (Annex 4). Countries will have only one year after WHO notification to implement post global eradication requirements. Advanced preparations are advised. [ To Top ] This phase begins when one year has elapsed without isolation of wild poliovirus anywhere in the world. During this phase nations: During this phase, nations:
The goal of this phase is to reduce the risk of wild poliovirus transmission from stored virus stocks and clinical materials at a time when universal immunization continues and wild polioviruses no longer circulate anywhere in the world. 1. Notifying laboratories when poliovirus transmission has stopped WHO will notify all nations that wild poliovirus transmission has stopped when one year has passed with no evidence of wild poliovirus circulation anywhere in the world (Year 1). Nations will inform agencies/institutions and laboratories on the National Inventory that global certification biosafety requirements are to be implemented no later than one year from the date of the announcement (Year 2). During the third year nations will submit documentation to the Global Certification Commission that effective containment is in place (Year 3). 2. Implementing biosafety options An underlying principle of poliovirus laboratory containment is that most laboratories do not have a need for long-term retention of wild poliovirus infectious and potential infectious materials. Destruction of such materials is strongly encouraged. Laboratories should critically evaluate the considerable personal and institutional responsibilities inherent in retaining a virus that is no longer being transmitted in nature. Laboratories that do not implement the required containment conditions must render all wild poliovirus materials non-infectious, destroy by autoclaving or incineration (Annex 2), or transfer them to a laboratory that meets the appropriate containment level. By definition, no clinical materials collected during the global certification phase are infectious for wild poliovirus, unless the virus re-emerges or VDPV is is detected. The threat of laboratory infection comes principally from stored materials collected before wild poliovirus transmission stopped. A small number of laboratories are expected to retain wild poliovirus materials for research purposes. Of particular importance is research relevant to defining the final strategy for stopping polio immunization. Other research laboratories in larger institutions are anticipated to retain collections of potential wild poliovirus infectious materials valuable for studying other diseases. Laboratories retaining such materials should do an internal risk assessment (Annex 1) and implement biosafety measures appropriate for the laboratory activities being performed (Box 6). For containment purposes, samples are considered polio-free immediately after the date of the last documented case for a given country. Experience has shown that widespread transmission ceases well before the last case is identified. The likelihood of collecting a virus positive specimen at random after that date is remote. All wild poliovirus infectious materials (Box 2) must be handled under BSL-3/polio conditions. All activities with potential wild poliovirus infectious materials (Box 3) that involve inoculating poliovirus permissive cells or animals, that is, any biologic system in which polioviruses replicate, must also be performed under BSL-3/polio conditions. All other activities involving potential wild poliovirus infectious materials may be handled safely within a certified class II biological safety cabinet inside a BSL-2/polio laboratory (Box 5). Potential wild poliovirus infectious materials may be centrifuged in the open laboratory if sealed heads or centrifuge safety cups are used and these are only opened within a biological safety cabinet.
Implementing Biosafety Level 3/Polio: BSL-3 (the high containment laboratory) includes all BSL-2 requirements with additional emphasis on protecting personnel in adjacent areas, the community, and the environment. Specific requirements are defined for personal protective clothing, laboratory design, use of laboratory equipment, and medical surveillance of laboratory staff. The laboratory should be separated from high traffic areas of the building with access restricted to authorized personnel. Biosafety provisions must be made for air, water, and materials entering and leaving the laboratory, as described in the 2002 WHO Laboratory Biosafety Manual (3rd edition).30 The BSL-3/polio laboratory (Box 7) incorporates all BSL-3 practices, but specifies additional requirements for storage and transfer of wild poliovirus infectious materials (Box 8).
Implementing storage requirements: Poliovirus infectious materials stored under secure conditions pose no inherent risk of transmission. The risk emerges when these materials are removed from storage. Infectious materials are kept in locked freezers within the BSL-3/polio facility with restricted access. Potential wild poliovirus infectious materials are clearly marked as such, stored in locked freezers with restricted access, inventoried and documented. Ideally these freezers are located within laboratories having a BSL-2/polio facility. As described in BSL-2/polio, a leak-proof, unbreakable secondary container should be used to avoid spills and breakages when transferring materials from freezers to safety cabinets. This practice is particularly important when potential wild poliovirus infectious materials are located in freezers outside the laboratory. Written laboratory procedures provide clear instructions for responding to spillages, breakages and accidents that may occur when transferring materials. Storage requirements are listed in Box 8.
3. Documenting containment for Global Certification Each Regional Certification Commission must submit satisfactory documentation to the Global Certification Commission that all laboratories in the Region with wild poliovirus infectious or potential infectious materials have either:
Documentation should include:
[ To Top ] This phase begins after the Global Commission has certified the world as polio free and international bodies have agreed on post certification immunization policies.33,34 The four possible immunization scenarios include:
Immunization policies will be based on outcomes of current research, post-eradication experiences, and assurances that surveillance, vaccine stockpiles, and emergency response plans are adequate if polio should re-emerge. Laboratory containment requirements for wild as well as OPV viruses are anticipated to be more stringent in those countries that elect not to immunize against polio, in keeping with the increasing consequences of inadvertent transmission of wild poliovirus from the laboratory to a growing non-immune community. [ To Top ]
[ To Top ]
*The year of the last indigenous virologically confirmed case is used - cases due to imported wild poliovirus or circulating vaccine
derived poliovirus are not reflected on this table. "Ongoing" refers to countries still considered endemic for wild poliovirus in
2001 (shaded). [ To Top ] ANNEX 2: Methods for disposal of wild poliovirus infectious or potential infectious materials30 Sterilization (use of autoclaves) Moist steam under pressure is the most effective method of sterilization of laboratory materials.
Incineration Incineration is the method of choice for final disposal of contaminated waste, including carcasses of laboratory animals, preferably after autoclaving. Incineration of infectious materials is an alternative to autoclaving only if:
Final disposal The disposal of laboratory and medical waste is subject to various national regulations. In general, ash from incinerators may be treated in the same way as normal domestic waste and removed by local authorities. Autoclaved waste may be disposed of by off-site incineration or in licensed landfill sites. [ To Top ] ANNEX 3: BSL-2/polio biosafety requirements Physical Facilities
Operational Practices
[ To Top ] ANNEX 4: BSL-3/polio containment requirements Physical Facilities
Operational Practices
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Results | Support This page last reviewed October 15, 2002 United States Department of Health and Human Services |
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