"The second important feature evident from the review of age-specific attack rates is that school children invariably have the highest attack rates during both pandemic and interpandemic periods. Epidemiologic studies during pandemics have demonstrated that children are important for spread of virus in the community. Observations made during the two major pandemics of this century reinforce the thesis that school children are important in the spread of influenza. Even though the populations were universally susceptible to the new influenza viruses that emerged in 1918 and 1957, and even though both viruses had seeded the population in the preceding spring and summer, the first major wave did not occur until schools were in session. Peak activity of both pandemics occurred in late October after school had been in session for 6-8 weeks. For interpandemic periods, observations in Houston have demonstrated that schoolchildren predominate among persons presenting for health care during the early stage of influenza epidemics. The age distribution of culture-positive patients changes during the course of the epidemic, with a shift to preschool children and adults during the latter part of the epidemic (table 4). School absenteeism occurs in the first part of the epidemic and employee absenteeism occurs during the later part. Hospitalizations of persons aged 65 years and older tend to occur during the last half of the epidemic, and pneumonia-influenza deaths are lagged at least 2 weeks after the peak of community morbidity. All of these observations support the thesis that school children are important disseminators of the virus in the community for both pandemic and interpandemic influenza. A series of family studies also have demonstrated that children are the main introducers of influenza into the household, and have found that immunization of school children would be effective for epidemic control."
Influenza, commonly known as the flu, is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin one to four days after exposure to the virus and last for about two to eight days. Diarrhea and vomiting can occur, particularly in children. Influenza may
"Influenza pandemics are events that have occurred in the past and will undoubtedly occur in the future. There is uncertainty about when the next influenza pandemic will occur, who will be most impacted, and how many will fall victim to this viral disease. These uncertainties make communicating the risk and consequences of pandemic influenza a greater communication challenge than the usual public health threats."
Influenza"The survival data for TGEV and MHV suggest that enveloped viruses can remain infectious on surfaces long enough for people to come in contact with them, posing a risk for exposure that leads to infection and possible disease transmission. This risk may also occur for other enveloped viruses, such as influenza virus. The potential reemergence of SARS or the emergence of new strains of pandemic influenza virus, including avian and swine influenza viruses, could pose serious risks for nosocomial disease spread via contaminated surfaces. However, this risk is still poorly understood, and more work is needed to quantify the risk of exposure and possible transmission associated with surfaces."
Influenza"The small British Crown dependency of Tristan da Cunha is one of the most isolated points on the planet. Over 1700 miles off the coast of South Africa, it is home to fewer than 300 permanent inhabitants. The island’s capital, Edinburgh of the Seven Seas, is commonly considered to be the most remote permanent human settlement. Without suitable ground for a paved airstrip, Tristan da Cunha’s only lifeline to the outside world is by sea. In 1971, the supply ship Tristania brought an unwelcome stowaway to the island: the alphainfluenzavirus H3N2, known as the Hong Kong flu at the time. By winter’s end, 96% of the population would contract influenza, with almost a third experiencing at least two distinct episodes of illness."
Influenza"Waterbirds, to an influenza researcher, are more than majestic swans and charming mallards. They are instead stealthy vectors of novel influenza viruses, some of natures bioterrorist agents, chauffeuring dangerous microbes from place to place."
Influenza"The use of licensed inactivated trivalent influenza vaccine is increasing, but even if all high risk persons currently given priority for this vaccine should be vaccinated each year, influenza epidemics would continue to occur. Healthy school children, preschool children in day care, college students, and working adults would continue to have high morbidity and would continue to spread the virus in the community. Vulnerable high risk patients would be at risk because of repeated challenge to their immunity by contract with infected persons. Recent pandemics illustrate another problem that must be faced with an impending pandemic. The time between recognition of the emergence of a new pandemic virus and the occurrence of the first wave may be short."
Influenza"As we now know, wild birds are the natural reservoir for influenza A viruses. With extensive antigenic and genetic diversity inherent among influenza virus surface proteins, a strain to which humans are immunologically naïve could jump the species barrier at any time. A(H5N1) viruses and, more recently, A(H7N9) viruses, are two such examples. However, swine are also recognized as a “mixing vessel” for influenza viruses, and over the past two decades, there has been an increase in human cases following exposure to infected pigs. There is clearly, and alarmingly, a vast diversity of zoonotic sources of influenza A viruses that could acquire a transmissible phenotype in humans and cause a pandemic."
Influenza