Category: Etiology

New pathogens, and diseases old and new. I) Afipia felis and Rochalimaea. II) Parvovirus B 19. III) herpesvirus 6

Abstract:

The paper describes events that in the last fifteen years, have led to the identification of the aetiological agents of three widely known diseases: cat scratch disease, erythema infectiosum and exanthem subitum. The particular features of Afipia felis and Rochalimaea, Parvovirus B 19 and Herpesvirus 6 are presented.

The paternity of new diseases (i.e. bacillary angiomatosis, bacillary peliosis hepatitis, LES-like syndrome, chronic fatigue syndrome, petechial glove and sock syndrome, etc.) has also been attributed to some of these pathogens as has the paternity of some older ones (i.e. aplastic crisis, erythroblastosis fetalis, trench fever, hepatitis, opportunistic infection, etc.).

It has been argued that the same pathogen can cause different diseases depending on the immunogenic state of the subject. To date, persisting difficulties in isolating the pathogen or differentiating between latent or active infection, still in some cases raises doubts concerning the attribution of the disease to a specific agent.

New immunological or molecular techniques, allowing the direct detection of in vivo replication, are still needed in order to establish a sure connection between some of these agents and some of these diseases. Progress here will both give more accurate data about the epidemiology of some diseases and allow us to apply more appropriate treatment and prevention techniques.

 

Source: Zannolli R, Morgese G. New pathogens, and diseases old and new. I) Afipia felis and Rochalimaea. II) Parvovirus B 19. III) herpesvirus 6. Panminerva Med. 1995 Dec;37(4):238-47. http://www.ncbi.nlm.nih.gov/pubmed/8710408

 

Reducing heterogeneity in chronic fatigue syndrome: a comparison with depression and multiple sclerosis

Abstract:

Chronic fatigue syndrome (CFS) is a heterogeneous illness characterized by a high prevalence of psychiatric problems. We reasoned that we could reduce heterogeneity by excluding patients with psychiatric problems preceding CFS.

We compared the functional status, mood, fatigue level, and psychiatric status of this more homogeneous group of CFS patients with the same parameters in patients with mild multiple sclerosis and in patients with major depression or dysthymia.

Patients with CFS and those with multiple sclerosis were similar in terms of level of anger, severity of depression, level of anxiety, and frequency of current psychiatric diagnoses. Patients with CFS resembled depressed patients in having impaired vigor and experiencing substantial fatigue and confusion–problems constituting part of the case definition of CFS.

The group with CFS was not psychologically vulnerable before the development of this condition and maintained adequate networks of social support despite disabling illness.

Stratification to exclude patients with prior psychiatric disease and those with mild CFS allowed us to define a group of patients with CFS who more resembled patients with mild MS than patients with major depression or dysthymia and thus were more likely to have illness with an infectious or immunologic cause. Use of such a stratification strategy should prove important in testing of the viral/immunologic hypothesis of the etiology of CFS.

 

Source: Natelson BH, Johnson SK, DeLuca J, Sisto S, Ellis SP, Hill N, Bergen MT. Reducing heterogeneity in chronic fatigue syndrome: a comparison with depression and multiple sclerosis. Clin Infect Dis. 1995 Nov;21(5):1204-10. http://www.ncbi.nlm.nih.gov/pubmed/8589144

 

A preliminary investigation of chlorinated hydrocarbons and chronic fatigue syndrome

Abstract:

OBJECTIVE: To determine whether serum levels of chlorinated hydrocarbons are elevated in patients with chronic fatigue syndrome.

METHODS: Chlorinated hydrocarbon levels were measured in 22 patients with chronic fatigue syndrome (CFS) (as defined by the Centers for Disease Control [CDC]); in 17 patients with CFS symptoms whose history of exposure to toxic chemicals excluded them from the research definition of CFS; and in 34 non-CFS control subjects matched for age and sex.

RESULTS: DDE (1,1-dichloro-2,2-bis (p-chlorophenyl) ethene) was detected in all serum samples at levels over 0.4 ppb. The incidence of hexachlorobenzene (HCB) contamination (> 2.0 ppb) was 45% in the CFS group, compared with 21% in the non-CFS control group (P < 0.05). The CFS group had a significantly higher total organochlorine level (15.9 ppb; SEM, 4.4) than the control group (6.3 ppb; SEM, 1.1; P < 0.05). The toxic exposure group also had a higher mean organochlorine level (13.6 ppb; SEM, 6.2) than the control group, but the difference was not statistically significant. DDE and HCB comprised more than 90% of the total organochlorines measured in each of the groups.

CONCLUSION: The results suggest that recalcitrant organochlorines may have an aetiological role in CFS. There were no significant differences in serum organochlorine concentrations between CFS patients and chronic fatigue patients with a history of toxic chemical exposure. Therefore, exclusion of patients from the CDC research definition of CFS on the basis of a reported history of known exposure to toxic chemicals is not valid. The role of low-level organochlorine bioaccumulation in the development of CFS symptoms requires further investigation.

 

Source: Dunstan RH, Donohoe M, Taylor W, Roberts TK, Murdoch RN, Watkins JA, McGregor NR. A preliminary investigation of chlorinated hydrocarbons and chronic fatigue syndrome. Med J Aust. 1995 Sep 18;163(6):294-7. http://www.ncbi.nlm.nih.gov/pubmed/7565234

 

Can the chronic fatigue syndrome be defined by distinct clinical features?

Abstract:

To determine whether patients diagnosed as having chronic fatigue syndrome (CFS) constitute a clinically homogeneous class, multivariate statistical analyses were used to derive symptom patterns and potential patient subclasses in 565 patients. The notion that patients currently diagnosed as having CFS constitute a single homogeneous class was rejected.

An alternative set of clinical subgroups was derived. The validity of these subgroups was assessed by sociodemographic, psychiatric, immunological and illness behaviour variables. A two-class statistical solution was considered most coherent, with patients from the smaller class (27% of the sample) having clinical characteristics suggestive of somatoform disorders. The larger class (73% of sample) presented a more limited combination of fatigue and neuropsychological symptoms, and only moderate disability but remained heterogeneous clinically. The two patient groups differed with regard to duration of illness, spontaneous recovery, severity of current psychological morbidity, utilization of medical services and CD8 T cell subset counts. The distribution of symptoms among patients was not unimodal, supporting the notion that differences between the proposed subclasses were not due simply to differences in symptom severity.

This study demonstrated clinical heterogeneity among patients currently diagnosed as CFS, suggesting aetiological heterogeneity. In the absence of discriminative clinical features, current consensus criteria do not necessarily reduce the heterogeneity of patients recruited to CFS research studies.

 

Source: Hickie I, Lloyd A, Hadzi-Pavlovic D, Parker G, Bird K, Wakefield D. Can the chronic fatigue syndrome be defined by distinct clinical features? Psychol Med. 1995 Sep;25(5):925-35. http://www.ncbi.nlm.nih.gov/pubmed/8588011

 

The validity and reliability of the fatigue syndrome that follows glandular fever

Abstract:

The validity and reliability of an empirically defined fatigue syndrome were tested in a prospective cohort study of 245 primary care patients, with glandular fever or an upper respiratory tract infection. Subjects were interviewed three times in the 6 months after onset. Subjects with the empirically defined fatigue syndrome were compared with those who were well and those who had a psychiatric disorder.

The validity of the fatigue syndrome was supported, separate from psychiatric disorders in general and depressive disorders in particular. Only 16% of subjects with the principal component derived fatigue factor also met criteria for a psychiatric disorder (excluding pre-morbid phobias). Compared with subjects with psychiatric disorders, subjects with the operationally defined fatigue syndrome reported more severe physical fatigue, especially after exertion, were just as socially incapacitated, had fewer mental state abnormalities, and showed little overlap on independent questionnaires. A more mild fatigue state also existed.

Both fatigue syndrome and state were more reliable diagnoses over time than depressive disorders. The empirically defined syndrome probably is a valid and reliable condition in the six months following glandular fever.

 

Source: White PD, Grover SA, Kangro HO, Thomas JM, Amess J, Clare AW. The validity and reliability of the fatigue syndrome that follows glandular fever. Psychol Med. 1995 Sep;25(5):917-24. http://www.ncbi.nlm.nih.gov/pubmed/8588010

 

The existence of a fatigue syndrome after glandular fever

Abstract:

This prospective cohort study was designed to test whether a distinct fatigue syndrome existed after the onset of glandular fever.

Two hundred and fifty primary care patients, with either glandular fever or an ordinary upper respiratory tract infection (URTI) were interviewed three times in the 6 months after the clinical onset of their infection. At each interview a standardized psychiatric interview was given and physical symptoms were assessed. There were 108 subjects with and Epstein-Barr virus (EBV) infection; 83 subjects had glandular fever not caused by EBV and 54 subjects had an ordinary URTI. Five subjects were excluded because they had no evidence of an infection.

Principal components analyses of symptoms supported the existence of a fatigue syndrome, particularly in the two glandular fever groups. The addition of symptoms not elicited by the standard interviews gave the full syndrome. This included physical and mental fatigue, excessive sleep, psychomotor retardation, poor concentration, anhedonia, irritability, social withdrawal, emotional lability, and transient sore throat and neck gland swelling with pain. A fatigue syndrome probably exists after glandular fever.

 

Source: White PD, Thomas JM, Amess J, Grover SA, Kangro HO, Clare AW. The existence of a fatigue syndrome after glandular fever. Psychol Med. 1995 Sep;25(5):907-16. http://www.ncbi.nlm.nih.gov/pubmed/8588009

 

Chronic intestinal candidiasis as a possible etiological factor in the chronic fatigue syndrome

Abstract:

The chronic candidiasis syndrome, also known as the Candida-related complex, putatively caused by the overgrowth of Candida albicans in the gastrointestinal tract and secondarily in the genital organs, is briefly described.

Patients with this disorder have many of the same symptoms as those with the chronic fatigue syndrome, except for the recurrent flu-like symptoms of the latter disorder. The positive response of a large number of patients with the chronic fatigue syndrome (CFS) to an oral antifungal agent and a diet for intestinal candidiasis has been described by another clinician.

There is evidence that Candida albicans infection of the mucous membranes depresses T cell and natural killer (NK) cell function. Similar abnormalities of immune function are found in the CFS. The function of cytotoxic T cells, T helper cells, and NK cells is important in preventing reactivation of infections from Epstein-Barr virus, cytomegalovirus, and other herpesviruses.

Reactivation of one or more of these viruses could lead to the expression of the flu-like symptoms in the CFS. Yet the immune dysfunction found in this disorder has been considered the primary underlying causal factor.

It is proposed that chronic intestinal candidiasis may be an agent which leads to immune depression in many CFS patients and therefore that it could be a causal factor in CFS.

 

Source: Cater RE 2nd. Chronic intestinal candidiasis as a possible etiological factor in the chronic fatigue syndrome. Med Hypotheses. 1995 Jun;44(6):507-15. http://www.ncbi.nlm.nih.gov/pubmed/7476598

 

Postinfectious fatigue: prospective cohort study in primary care

Abstract:

The idea that chronic fatigue has an infectious origin has become popular, but the main evidence for such an association has come from retrospective case-control studies, which are subject to ascertainment bias. We report a prospective study of the outcome of clinically diagnosed infections in patients presenting to UK general practitioners.

Questionnaires assessing fatigue and psychiatric morbidity were sent to all patients aged 18-45 years in the study practices. The prevalence of chronic fatigue and chronic fatigue syndrome was then ascertained among 1199 people aged 18-45 who presented to the general practitioners with symptomatic infections and in 1167 people who attended the surgeries for other reasons. 84% were followed up at 6 months. 9.9% of cases and 11.7% of controls reported chronic fatigue (odds ratio 1.0 [95% CI 0.6-1.1]). There were no differences in the proportions who met various criteria for chronic fatigue syndrome. No effect of infection was noted when we excluded subjects who reported fatigue or psychological morbidity at the baseline screening.

The strongest independent predictors of postinfectious fatigue were fatigue assessed before presentation with clinical infection (3.0 [1.9-4.7]) and psychological distress before presentation (1.8 [1.2-2.9]) and at presentation with the acute infection (1.8 [1.1-2.8]). There was no effect of sex or social class. Our study shows no evidence that common infective episodes in primary care are related to the onset of chronic fatigue or chronic fatigue syndrome.

Comment in:

Viral illness and chronic fatigue (syndrome). [Lancet. 1995]

Viral illness and chronic fatigue (syndrome) [Lancet. 1995]

Viral illness and chronic fatigue (syndrome). [Lancet. 1995]

Viral illness and chronic fatigue (syndrome) [Lancet. 1995]

Viral illness and chronic fatigue (syndrome). [Lancet. 1995]

 

Source: Wessely S, Chalder T, Hirsch S, Pawlikowska T, Wallace P, Wright DJ. Postinfectious fatigue: prospective cohort study in primary care. Lancet. 1995 May 27;345(8961):1333-8. http://www.ncbi.nlm.nih.gov/pubmed/7752755

 

Epstein-Barr virus (EBV) and the chronic fatigue syndrome: normal virus load in blood and normal immunologic reactivity in the EBV regression assay

Abstract:

The etiology of chronic fatigue syndrome (CFS) is unknown. Some patients have high antibody titers to viral capsid antigen (VCA) and early antigen (EA) of Epstein-Barr virus (EBV), suggesting that reactivation of EBV is involved. We investigated virus load (spontaneous transformation) and immunologic regression of EBV-induced transformation in peripheral blood mononuclear cells (PBMCs) from 10 selected patients with CFS who had high antibody titers to VCA and EA. The outcome was compared with that for nine healthy controls and one patient with severe chronic active EBV infection (SCAEBV). There were no significant differences in viral load between patients and healthy controls. Immunologic regression of in vitro-transformed PBMCs was also equally efficient in patients and controls. The SCAEBV-infected patient and two controls, who were all seronegative for EBV, showed impaired regression. In conclusion, we were unable to demonstrate a role for reactivation of EBV in CFS, even in selected patients with high titers of antibody to VCA and EA of EBV.

 

Source: Swanink CM, van der Meer JW, Vercoulen JH, Bleijenberg G, Fennis JF, Galama JM. Epstein-Barr virus (EBV) and the chronic fatigue syndrome: normal virus load in blood and normal immunologic reactivity in the EBV regression assay. Clin Infect Dis. 1995 May;20(5):1390-2. http://www.ncbi.nlm.nih.gov/pubmed/7620030

 

Chronic fatigue syndrome. 1: Etiology and pathogenesis

Abstract:

Chronic fatigue syndrome (CFS) is a disorder of unknown etiology characterized by debilitating fatigue and other somatic and neuropsychiatric symptoms. A range of heterogeneous clinical and laboratory findings have been reported in patients with CFS. Various theories have been proposed to explain the underlying pathophysiologic processes but none has been proved.

Research findings of immunologic dysfunction and neuroendocrine changes suggest the possible dysregulation of interactions between the nervous system and the immune system. Without a clear understanding of its etiopathogenesis, CFS has no definitive treatment.

Management approaches have been necessarily speculative, and they have evolved separately in a number of medical and nonmedical disciplines. The results of several controlled treatment studies have been inconclusive. An accurate case definition identifying homogeneous subtypes of CFS is needed. The integration of medical and psychologic treatment modalities and the use of both biologic and psychologic markers to evaluate treatment response will enhance future treatment strategies.

 

Source: Farrar DJ, Locke SE, Kantrowitz FG. Chronic fatigue syndrome. 1: Etiology and pathogenesis. Behav Med. 1995 Spring;21(1):5-16. http://www.ncbi.nlm.nih.gov/pubmed/7579775