By Ramaz Mitaishvili
Glendale, CA
1. Introduction
1.1. Pandemic influenza is considered to be a relatively high probability event, yet no one knows when the next pandemic will occur and there may be very little warning. Most experts believe that there will be between one to six months between the identification of a novel influenza virus and the time that widespread outbreaks begin to occur in the Abkhazia and Caucasus region as well as Bleak Sea countries. Outbreaks are expected to occur simultaneously throughout the all those areas, preventing relocation of human and material resources. The effect of influenza on individual communities will be relatively prolonged, an estimated six to eight weeks. Due to the prolonged nature of a pandemic influenza event, the World Health Organization (WHO) has defined phases to a pandemic in order to facilitate coordinated plans.
The Abkhazia Institute for Social and Economic Research has developed its own pandemic phases for planning purposes, convenient for proposed Center for Disease Control and Prevention
1.2. Influenza A virus is a member of the family Orthomyxoviridae. Influenza viruses are enveloped, with a segmented, single-stranded RNA genome. This family also contains influenza B and C viruses. Point mutations in the envelope protein hemagglutinin (H), referred to as antigenic drift, result in the emergence of new strains of influenza A and B viruses and the resultant annual outbreaks and epidemics. Subtyping of influenza A virus is based on antigenic characteristics of two envelope proteins, H and neuraminidase (N). New influenza A virus subtypes emerge as the result of reassortment of H and N sequences from two different subtypes, referred to as antigenic shift. These new subtypes are responsible for influenza pandemics. There are currently 16 recognized H subtypes and 9 recognized N subtypes. While virtually all combinations of influenza A subtypes naturally infect waterfowl and shorebirds, certain subtypes infect poultry and mammalian species. Subtypes H1N1, H3N2, H2N2 and H1N2 have circulated, or are currently circulating widely, among humans. Subtype H5N1, causing highly pathogenic avian influenza, was identified in 1996 in southern China. Influenza A H5N1 is significant, though not unique, in its ability to cross normal species barriers and directly infect humans. Avian subtypes H9N2 and H7N7 are also known to cause infection in humans, so public health influenza surveillance programs monitor for emergence of any novel strains in humans. However, the wide geographical distribution of H5N1 in avian species, and the number and severity of human infections are unprecedented. If, or when, the virus reassorts to a strain transmitted readily among humans, and unless there is a dramatic decrease in the pathogenicity of the resulting virus, the result will likely be an influenza pandemic with mortality rates not seen since the 1918 pandemic.
1.2.1. Epidemiology
The classical epidemiologic cycle of influenza A virus includes wild waterfowl and shorebirds, which are naturally infected; domestic waterfowl and poultry, which acquire virus from wild birds; pigs, which serve as “mixing vessels” for both avian and mammalian adapted strains; and humans, who are susceptible to the reassorted viruses. Reassortment can also occur during human-to-human transmission. Influenza A virus also infects maritime mammals, including seals and whales, dogs, and horses. The H5N1 virus has bypassed this epidemiologic cycle, crossed normal species barriers, and is capable of being transmitted directly from poultry to humans. First identified as a cause of highly pathogenic avian influenza in southern China in 1996, the virus has since spread to Southeast Asia, Middle East, Eastern and Western Europe, and Africa. H5N1 has been found in domestic fowl and a variety of migratory and resident wild bird species. Avian influenza strains infect the intestinal tract and are shed at high titers in feces. Transmission rates are high among birds congregating at bodies of water. The presence of H5N1 in a number of migratory bird species has resulted in its rapid spread among continents. In addition to birds, the virus has also been found in several mammalian species. Felines have become infected as a result of consumption of infected dead birds. Human infections caused by H5N1 were first identified in 1997. Human H5N1 infections are the result of exposure to high viral titers in infected birds or feces. There is evidence of human-to-human transmission, yet secondary cases are very limited due to avian host specificity of H5N1. Hundreds of confirmed human cases of avian influenza H5N1 have been reported to the World Health Organization, and the mortality rate has been approximately 50%. Human cases have been reported from Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Thailand, Turkey, and Viet Nam.
Influenza pandemics result from the emergence of antigenically distinct subtypes of influenza A virus. During the twentieth century, influenza pandemics occurred in 1918, 1957 and 1968. The subtypes causing these pandemics all had avian origins, and adapted to high transmissibility among humans. Pathogenicity among the pandemic virus strains varied.
Influenza virus is considered a Category C biothreat agent. Agents in this category are emerging, readily available, and easily disseminated. In addition, they are capable of causing high morbidity and mortality rates.
1.2.2. Clinical Features
Influenza caused by H5N1 shares features with those caused by the Spanish influenza pandemic of 1918. Morbidity and mortality are severe in previously healthy, young and middle-aged persons. The innate immune response is in part responsible for pathogenesis, causing fluid accumulation in the lungs. While influenza caused by H5N1 is notable for its aggressive course and high mortality rates, evidence indicates that mild disease and asymptomatic infections occur. Symptomatic cases are characterized by high fever, cough, and lower respiratory tract symptoms (shortness of breath, pulmonary infiltrates) in virtually 100% of patients. Diarrhea occurs more frequently than with influenza caused by human-adapted subtypes. The frequency of pneumonia and diarrhea distinguish avian from seasonal influenza. Over 50% of reported H5N1 influenza cases were fatal. Death is primarily due to respiratory or multi-organ failure. Unlike human-adapted subytpes, H5N1 is found in relatively high titers in lower respiratory tract specimens, throat swabs and stool. Although it is not known if infections with a pandemic strain will have frequently demonstrable viremia, the current H5N1 virus has been isolated from serum.
1.2.3. Treatment and Prevention
Recent isolates of influenza A H5N1 show varying resistance to the adamantanes (amantadine and rimantadine): clade 1 viruses are resistant, while the majority of clade 2 viruses are sensitive. The neuraminidase inhibitors, oseltamivir and zanamivir, are active against influenza A H5N1. However, the emergence of high-level resistance to oseltamivir during oseltamivir treatment has been demonstrated in some patients with influenza A H5N1 infections. These two patients had detectable virus at the end of a full course of treatment. An important component of avian influenza A H5N1 pandemic preparedness programs is the stockpiling of adequate supplies of neuraminidase inhibitors. Clinical trials and development efforts are currently ongoing for both inactivated and attenuated influenza A H5N1 vaccines.
2. Purpose
The purpose of this plan is to provide a guide for the Center for Disease Control and Prevention in Abkhazia for detecting and responding to an influenza pandemic. This plan must be periodically reviewed and updated to ensure that its assumptions, resources, priorities, and plans are consistent with current knowledge and changing infrastructure. In addition, in the event of a pandemic, the judgments of the public health leadership, based on the epidemiology of the outbreak and the extent of population infection, may alter or override anticipated strategies and plans.
3. Georgia Government’s responsibilities
The Georgian government is responsible for nationwide coordination of the pandemic influenza response. Specific areas of responsibility include the following:
• Surveillance in the Georgia
• Epidemiological investigation in the Georgia
• Development and use of diagnostic laboratory tests and reagents
• Development of reference strains and reagents for vaccines
• Vaccine evaluation and licensure
• Determination of populations at highest risk and strategies for vaccination and antiviral use
• Assessment of measures to decrease transmission (such as travel restrictions, isolation, and quarantine)
• Deployment of purchased vaccine
• Deployment of antiviral agents
• Evaluation of the efficacy of response measures
• Evaluation of vaccine safety
• Deployment of the Epidemic Intelligence Service officers
• Medical and public health communications
4. Proposed Center for Disease and Control and Prevention (PCDCP) Responsibilities
PCDCP is responsible for coordination of the pandemic influenza response within and between their jurisdictions. Specific areas of responsibility include the following:
• Identification of public and private sector partners needed for effective planning and response.
• Development of key components of pandemic influenza preparedness plan (surveillance, vaccine and antiviral distribution, disease control, and communications) following guidance provided by the WHO in the national Pandemic Influenza Preparedness and Response Plan.
• Integration of pandemic influenza planning with other planning activities conducted under Georgian Government, cooperative agreements with Abkhazia, South Ossetia and countries who will participate in our program.
• Coordination with local areas to ensure development of local plans as called for by the AISER plan and provide resources, such as templates to assist in planning process.
• Development of data management systems needed to implement components of the plan.
• Assistance to local areas in exercising plans.
• Coordination with adjoining jurisdictions and separatist Government.
5. Assumption
• An influenza virus strain will likely emerge in a country other than the Georgia, but a novel strain could emerge first in the Abkhazia region of Georgia.
• The pandemic may occur during time periods not normally associated with the usual influenza season, and the pandemic strain may attack categories of people at different rates than that which normally occurs during the influenza season.
• There may be as little as one to six months warning before outbreaks begin in the Georgia, if the pandemic emerges outside this country.
• Although there may be isolated pockets, the pandemic could affect all areas of the state.
• When the pandemic occurs, vaccines and antiviral medicines will be in short supply and will have to be allocated on a priority basis.
• It will take six to eight months after the novel virus is identified before the vaccine is available for distribution, unless a DNA vaccine is developed and deemed safe and necessary.
• A second dose of vaccine (two to four weeks after the first) may be required to develop immunity to the novel virus.
• In a pandemic, vaccine purchase and distribution options include:
• public sector purchase and distribution of all pandemic influenza vaccine
• a mixed public-private system where public sector supply may be targeted to specific priority groups (e.g., health care workers and those providing essential public safety services) and those who may be underserved by the current system
• maintenance of the current, largely private, system
• The federal government has assumed responsibility for devising a liability program for vaccine manufacturers and persons administering the vaccine.
• Secondary bacterial infections following influenza illness may stress antibiotic supplies.
• Response to the demand for services may require non-standard approaches, including:
• Discharge of all but critically ill hospital patients
• Expansion of hospital capacity by using all available space and less than code beds
• Increase of patient ratio to hospital staff
• Recruitment of volunteers who can provide custodial services under the general supervision of health and medical workers
• Relaxation of practitioner licensure requirements as deemed appropriate, and
• Utilization of general purpose and special needs shelters as temporary health facilities.
• Educating the public about the rationale for priority groups for antivirals and vaccine will be an important aspect of public education.
• There will be widespread circulation of conflicting information, misinformation, and rumors. Communication must be coordinated among all relevant agencies to ensure consistent messages to the general public.
