Chronic mononucleosis--a legitimate diagnosis

Environmental perturbation, inflammation and behavior in healthy and virus-infected mice

The development of so-called "sickness behaviors" (e.g., anorexia, anhedonia, reduced social interaction, fatigue) during infectious and inflammatory disease has been linked to facets of the immune response. Such problems can be particularly troublesome during chronic latent infection, as the host immune system must employ continual vigilance to maintain viral latency. Epstein-Barr virus (EBV) is a ubiquitous human gamma-herpesvirus that causes acute disease and establishes life-long latency in people. Murine gammaherpesvirus (MuGHV) is a natural pathogen of wild rodents that provides an experimental model for studying the pathophysiology of an EBV-like gamma-herpesvirus in mice. To evaluate this model with regard to sickness behavior and its exacerbation during a chronic latent viral disease, we exposed uninfected and MuGHV-infected C57BL/6J and BALB/cByJ mice to novel and potentially stressful environmental perturbations and measured the impact of these challenges on behavior and markers of inflammation. The data indicate that exposure of mice to environmental perturbations during the normal somnolent phase is associated with reduced activity during the subsequent active phase, despite an intervening rest period. Effects on inflammatory mediators were complex due to independent and interactive effects of infection status, mouse strain, and exposure to stressful environment. However, GCSF and MCP1 were consistently elevated in lung both immediately after and 12h after exposure to a "dirty" cage containing the resident mouse (DCR); this increase occurred in both C57BL/6J and BALB/cByJ mice and was independent of infection status. At 12h after DCR, IL1β and IP10 were also consistently elevated in lung. In response to DCR, BALB/cByJ mice showed a greater number of significant cytokine effects than did C57BL/6J mice. With regard to infection status, IP10 was consistently elevated in lung at both time points regardless of mouse strain or DCR exposure. Several analytes were affected by mouse strain in serum or lung at one or both time points, with most strain differences present in serum at E18. Taken together, the data show that exposure of mice to environmental perturbations is associated with systemic inflammation that is in part independent of genetic background or latent MuGHV infection and with reduced activity that could represent fatigue, depression, or other facets of sickness behavior.

Precipitating factors for the chronic fatigue syndrome

The etiology of the Chronic Fatigue Syndrome (CFS) is unknown but it is usually considered to be postinfectious or postviral. Many infecting agents have been suspected as causative but none has been proven. We investigated precipitating factors in 134 CFS patients through the use of a questionnaire, interview, clinical examination and serology for infecting agents; 35 healthy controls completed a similar questionnaire. CFS started with an apparently infectious illness in 96 (72%) but a definite infection was only found in seven of these 96 (7%). Thirty-eight (28%) had no apparent infectious onset: 15/38 (40%) had noninfectious precipitants (trauma, allergy, surgery). There was no apparent precipitating event in 23/38 (61%). Immunization was not a significant precipitant. Stressful events were very common in the year preceding the onset of CFS (114/134, 85%) but these occurred in only 2/35 (6%) of the controls (p < .0001). The onset of CFS may be associated with preceding stressful events and multiple other precipitants. An infectious illness is not uniformly present at the onset and no single infectious agent has been found; CFS is most likely multifactorial in origin.

[Chronic fatigue syndrome]

Reports on conditions of chronic fatigue associated with other somatopsychic symptoms after acute viral infections have led to the hypothesis of a "chronic fatigue syndrome" (CFS). Historical disease descriptions, like e.g. "myalgic encephalomyelitits", were updated by means of modern virological diagnostic techniques and data analysis. Several viral agents like enteroviruses, Epstein-Barr virus, Human-Herpesvirus 6 and other herpesviruses have been implicated for possible underlying infections. A preliminary disease definition by the Center for Disease Control (CDC) seeks to provide a rational basis for further etiological studies. In fact, there is growing consensus that the syndrome comprises various separate disease entities and causative agents. Today we can tentatively differentiate a "chronic mononucleosis" after infection with Epstein-Barr virus, an etiologically undetermined "postviral fatigue syndrome" and a fatigue syndrome of the myalgic type after Coxsackie-B virus infection. Furthermore, a valid diagnosis of CFS must be based on the exclusion of defined other diseases and the awareness of dealing with a hypothetical concept. As a result, current knowledge does not yet allow specific therapeutic recommendations.

Measles associated with coronary arteritis

A two-year-old girl with measles virus (MV) and chronic Epstein-Barr virus (EBV) infection developed lethal coronary aneurysmal arteritis accompanied by giant cell pneumonia, systemic lymphadenitis and hepatosplenomegaly. In her coronary arteries, lungs and aorta, cells containing intranuclear and intracytoplasmic inclusions, including syncytial giant cells, were detected, the presence of MV in the organs being proved by electron microscopic and immunofluorescent studies. Immunopathology further demonstrated MV to be disseminated in almost all organs other than lymph nodes. Clinical diagnosis of chronic EBV infection was established on the basis of persistent high titers of antibodies against capsid and early antigens of EBV and viral presence was confirmed by Southern blot hybridization in a mesenterial lymph node obtained at autopsy. To the best of our knowledge, this is the first description of MV association with coronary aneurysmal arteritis, raising the possibility that measles infection can cause severe vasculitis under immuno-suppressive states, such as that caused by chronic EBV infection.

Feelings of fatigue and psychopathology: a conceptual history

Since the 19th century, fatigue has received far more attention in the medical literature than feeling of fatigue. The latter is defined as a primary, sui generis feeling, which can be studied (and is experienced) independently of physical phenomena such as tiredness, and cognitive concomitants such as "not wanting to continue or initiate a task." The unexplained feeling of fatigue is a common medical complaint, and accompanies various medical and psychiatric conditions. Several meaning systems can be identified in relation to feeling of fatigue and provide material for construction of a measuring instrument. Such a scale will allow us to answer four questions: Is the feeling of fatigue a unitary and primary experience or sensation? Is it the same regardless of the clinical or social context in which it occurs? Are the somatic and cognitive accompaniments of feeling of fatigue an essential part of its definition? Does feeling of fatigue have a neurobiological basis?