Influenza Facts and Information
Typical seasonal flu epidemics reach their peak between November and March, as existing flu strains that are already in the general population result in outbreaks during the colder months. Recent concerns about person-to-person transmission of the H5N1 strain of avian flu in Southeast Asia have focused the efforts of oral health professionals on their response to a potential flu pandemic, possibly as part of sentinel systems alerting public health agencies about potential new flu strains. Here are some facts ...
... Flu Pandemic Update ...
An influenza, or “flu,” pandemic is a worldwide outbreak of disease. Pandemics may occur when a new influenza A strain emerges, causes serious illness, and spreads easily because people have little or no immunity against the new strain. Pandemics are different from seasonal outbreaks (epidemics) of influenza because they are caused by new A subtypes or by subtypes that have never circulated among people or have not circulated for a long time.
Pandemics develop and spread rapidly. Responding may be difficult because so much time is needed to develop new vaccines or other methods of protection against the virus.
In the 20th century, three influenza pandemics have led to extensive illness, death, social disruption, and economic loss. Each was caused by a new subtype of influenza A virus and spread within a year. Each of these viruses may be circulating in current populations today.
• 1918-1919 - “Spanish flu,” caused by the A strain, H1N1, resulted in the highest number of known influenza deaths. More than 500,000 people died in the United States alone, with up to 50 million deaths worldwide. Many people died within the first few days after infection, and others died of complications later. Unlike in other pandemics, nearly half of those who died were young, healthy adults.
• 1957-1958 - “Asian flu,” caused by the A strain, H2N2, resulted in about 70,000 U.S. deaths. First identified in China in late February 1957, the Asian flu spread to the United States by June 1957.
• 1968-1969 - “Hong Kong flu,” caused by the A strain, H3N2, resulted in 34,000 U.S. deaths. This virus was first detected in Hong Kong in early 1968 and spread to the United States later that year.
Influenza A virus types are generally found in wild birds. Pandemic flu strains result from a process called antigenic shift, caused when proteins found on the surface of the virus (either the hemagglutinin [HA] protein or the neuraminidase [NA protein]) combine in new ways. The new combinations result in sudden, major changes in the influenza A viruses. The emergence of a new virus, however, is only the first step toward a pandemic.
To cause a pandemic, a new virus subtype also must spread easily from person to person. Once a new pandemic flu virus emerges, it can cause seasonal epidemics of influenza for years. Both the U.S. Centers for Disease Control and Prevention and the World Health Organization (WHO) have monitoring and surveillance programs to detect influenza activity around the world, including the emergence of possible pandemic strains of influenza virus. WHO has developed a global influenza preparedness plan, which defines the stages of a pandemic, outlines WHO’s role, and makes recommendations for national measures before and during a pandemic. Go to http://www.who.int/csr/resources/publications/influenza/WHO_CDS_CSR_GIP_2005_5.pdf.
During the alert period, oral health professionals might be part of a sentinel system to notify local and state health professionals in the event of unusually high numbers of appointment cancellations or acutely ill patients, especially among younger, healthier adults.
Oral Health Research
Bacteria Commonly Found in Saliva Associated With Squamous Cell Cancer of the Oral Cavity
The July issue of the Journal of Translational Medicine reported that an elevated level of three bacteria commonly found in saliva is associated with squamous cell cancer of the oral cavity. The principal investigator for the study was Dr. Donna Mager, assistant member of the staff in the Department of Periodontology and Molecular Genetics at Forsyth Institute in Boston. The paper, The Salivary Microbiota as a Diagnostic Indicator of Oral Cancer: A descriptive, nonrandomized study of cancer-free and oral squamous cell carcinoma subjects (Mager et al., J Translational Research, July 2005), reported on comparison of bacterial content of saliva samples from two groups: a control group of 229 healthy subjects and a group of 45 patients diagnosed with oral cancer. Elevated levels of three bacterial species (Capnocytophaga gingivalis, Prevotella melaninogenica, and Streptococcus mitis) were observed in oral cancer patients, even when controlled for sex, age, and smoking history.
The results show promise for potential use as a diagnostic indicator for oral cancer. Unfortunately, oral cancer often is not detected early, and five-year survival rates for late-stage disease (about 54 percent) are not much better than they were in the 1970s. Future research will assess the relationships between oral bacteria and other cancers and disorders, as well as how saliva tests to detect these bacteria might predict early stages of oral cancer.
ORCA Meeting Highlights
The European Association of Caries Research (ORCA) conference was held July 6-9 with a scientific session at Indiana University. During this conference, scientists from around the world presented the latest data on remineralization and caries at a workshop titled, “Clinical Models Workshop: Remineralization-Demineralization, Precavitation, Caries.” The workshop’s goal was to develop a general consensus throughout the international scientific community regarding the acceptability of new, more efficient models for clinical trials that address the impact of caries-preventive measures.
Dr. J. Nor of the University of Michigan also presented a paper summarizing efforts to date to reproduce tooth structure. His paper, “Molecular Biology in the Bioengineering of Teeth,” discussed the status of current research on tooth tissue engineering and molecular signaling. Dr. Nor reported that it is now possible to induce remineralization of enamel, dentin regeneration, and pulp regrowth through the use of signaling compounds. For example, various compounds, such as BMP-2 and BMP-7, can induce dentin repair and dentin bridging into large spaces where dentin has been removed. Amelogenin (10 percent) combined with 1 ppm fluoride can be used to “grow” mineral, which is very similar to natural enamel. Fibroblasts can be used to generate pulp tissue. Using such techniques and others based on gene therapy, it seems likely that technology to promote tooth regeneration or growth can be developed. Dr. Nor noted that although these types of treatments are not yet practical, they may become the cornerstone of future dental treatments.
New Free Resources for Special Needs Oral Care
The National Maternal and Child Oral Health Resource Center (OHRC) has produced a new fact sheet, tip sheet, and resource guide to help you in providing oral care services for young people with special care needs.
The fact sheet, “Oral Health for Children and Adolescents With Special Health Care Needs: Challenges and Opportunities,” provides a basic overview of special care needs, including unmet needs, systemic and oral health issues, barriers to care (including reimbursement issues in publicly funded programs), and accessibility to qualified oral health professionals. Go to http://www.mchoralhealth.org/PDFs/SHCNfactsheet.pdf.
The tip sheet, “Strategies for Improving the Oral Health System of Care for Children and Adolescents With Special Health Care Needs,” is designed for persons planning and implementing programs of oral care for special needs children and adolescents. Go to http://www.mchoralhealth.org/PDFs/SHCNtipsheet.pdf.
The “Oral Health Services for Children and Adolescents With Special Health Care Needs: Resource Guide” provides a list of journal articles, materials, and federal agencies and national organizations that may serve as resources for ensuring optimal care. Go to http://www.mchoralhealth.org/PDFs/SHC NResGuide.pdf.