Clinical infectious diseases : an official publication of the Infectious Diseases Society of America
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Lemierre's syndrome is the classical presentation of human necrobacillosis. It is characterized by a primary infection in the head in a young, previously healthy person who subsequently develops persistent high fever and disseminated metastatic abscesses, frequently including a septic thrombophlebitis of the internal jugular vein. ⋯ Early diagnosis and prolonged appropriate antibiotic treatment with good anaerobic coverage are crucial to reduce morbidity and mortality. F. necrophorum also causes human necrobacillosis with foci caudal to the head, mainly in elderly patients with high mortality related to age and predisposing diseases, such as cancers of the primary focus.
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Immunosenescence is the state of dysregulated immune function that contributes to the increased susceptibility to infection of the elderly. Extensive studies of inbred laboratory animals and very healthy elderly humans have identified changes in immunity; these studies have identified limited phenotypic and functional changes in the T cell component of adaptive immunity. However, no compelling scientific evidence has shown that these changes have direct relevance to the common infections seen in the aged population. ⋯ First, it will review clinically relevant infections in the elderly, focusing on influenza and influenza virus vaccination and how chronic illness contributes to increased risk and severity of infection and/or failed vaccine response. Second, key changes in immunity will be reviewed, keeping a perspective of the impact of confounding variables in addition to age but focusing on age-related changes in the interaction of the innate and acquired components of immunity. If the goal is to prevent serious infections in the elderly, it appears that the field of geriatric immunology and/or infectious diseases is faced with the tremendous challenge of studying a very diverse population, including mildly immunocompromised/chronically ill individuals and very healthy elderly.
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Lyme disease, which is caused by Borrelia burgdorferi and transmitted in the United States primarily by Ixodes scapularis (the deer tick), is the most common vector borne disease in the United States. Its most frequent manifestation, a characteristic, expanding annular rash (erythema migrans), sometimes accompanied by myalgia, arthralgia, and malaise, occurs in nearly 90% of persons with symptomatic infection. Other manifestations of Lyme disease include seventh cranial nerve palsy, aseptic meningitis, and arthritis. ⋯ This problem is exacerbated by the frequent use of serological tests to eliminate the possible diagnosis of Lyme disease in persons with only nonspecific symptoms (such as arthralgia or fatigue) who have a very low probability that Lyme disease is the cause of their symptoms. Consequently, misdiagnosis is frequent and is the most common cause of failure of treatment. The prognosis for most persons with Lyme disease is excellent.
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Editorial Comment Comparative Study
Guidelines for community-acquired pneumonia: a tale of 2 countries.