Adenovirus type 2 encephalitis and concurrent Epstein-Barr virus infection in an adult man

Near-fatal Cerebral Edema Associated with Adenovirus Type 2 Infection in a Previously Healthy Infant

We report a near-fatal case of cerebral edema associated with adenovirus type 2 infection in a previously healthy 19-month-old boy. After 3 to 4 d of high fever and a series of seizures, he developed persistent loss of consciousness and irreversible respiratory arrest. Adenovirus type 2 infection was diagnosed by virus isolation from his stool and serology.

Neuropsychological sequelae of acute-onset sporadic viral encephalitis

Acute encephalitis is an inflammation of the brain parenchyma. In the USA, by estimation, 20,000 cases occur every year. A variety of cognitive deficits may persist after the acute stage, and they are often the sole cause of disability. Recent literature demonstrates the heterogeneity of both amnestic disorders and the outcome following encephalitis. Herpes simplex virus is the most commonly recognised single aetiology of sporadic encephalitis and it may be the cause of the most severe symptoms. Antiviral medication, however, seems to have improved the cognitive outcome when compared to the historical, untreated cases. The cognitive sequelae following herpes simplex virus encephalitis (HSVE) are best known and most commonly described, e.g., in textbooks, but they do not represent the typical symptomatology of encephalitis in general. Much less is unfortunately known about other types of encephalitis, those that account perhaps up to 80% of all cases, where both mild and severe defects have been observed. This article summarises the current knowledge.

Acute meningoencephalitis caused by adenovirus serotype 26

Adenoviridae are rare causes of meningoencephalitis in both immunocompetent and immunocompromised hosts. In this article the authors report a case of adenoviral meningoencephalitis caused by serotype 26 and its identification, not described previously, in cerebrospinal fluid (CSF) by PCR and brain tissue by immunohistochemical staining.

Involvement of adenovirus in clinical mononucleosis-like syndromes in young children

Although Epstein-Barr virus (EBV) commonly causes infectious mononucleosis (IM) or IM-like syndromes, other agents can be implicated. In this study, viral and parasitic screening was performed to determine the etiological agent of pediatric IM-like syndromes in 38 children. Adenovirus was the agent most frequently detected (47.3%), followed by EBV (31.5%) and cytomegalovirus (2.6%). Although the statistically significant difference between viral detection rates observed in patients who fulfilled clinical and hematological criteria and detection rates in those who presented clinical symptoms only (91.6% vs. 64.3%) indicates that hematological abnormalities are common in viral IM-like syndromes, the existence of syndromes of viral etiology without hematological criteria cannot be discarded. A further analysis showed an absence of lymphocytosis in adenovirus infections as well as a low number (14.3%) of EBV infections associated with increased neutrophils. These data suggest the usefulness of appropriate virological techniques for the detection of adenovirus in pediatric IM-like syndromes.

Cognitive outcome in acute sporadic encephalitis

Acute encephalitis is an inflammation of the brain parenchyma. In the United States, 20,000 cases occur yearly. A variety of cognitive deficits, often the sole cause of disability, may persist after the acute stage. Still, infectious diseases tend to be covered only briefly in neuropsychological handbooks. Recent literature demonstrates the heterogeneity of both amnestic disorders and the outcome following encephalitides. Herpes Simplex virus (HSV), the most common single etiology of sporadic encephalitis, usually causes the most severe symptoms. Modern antiviral medication, however, seems to improve the cognitive outcome. Much less is known about non-HSV encephalitides, where both mild and severe defects have been observed. This article summarizes the current knowledge and also calls upon a more active neuropsychological research in the area.

Isolation and characterization of adenovirus 5 from the brain of an infant with fatal cerebral edema

This report describes a fatal case of cerebral edema caused by adenovirus in a previously healthy 18-month-old infant who developed skin rash, pulmonary congestion, and fever and who died 6 days later. Adenovirus hexon gene sequences were detected in brain tissue and brain tissue cultures. The virus was typed as adenovirus 5.

Shorter survival in HIV-positive patients with diarrhoea who excrete adenovirus from the GI tract

Adenoviruses have been described as a cause of diarrhoea in patients infected with the human immunodeficiency virus (HIV). The prevalence of adenoviruses was studied in all HIV-positive patients presenting with diarrhoea at the Royal Free Hospital in London between 1991 and 1995. In addition, all postmortems carried out in HIV-positive individuals registered at the same centre between 1990 and 1997 were reviewed for evidence of adenovirus infection. Adenovirus was detected in 16.1% of patients presenting with diarrhoea. These individuals had a significantly lower CD4 count and were more likely to have had a diagnosis of acquired immunodeficiency syndrome (AIDS) than patients with diarrhoea in whom adenovirus was not detected. The median survival was 1 year compared with 2.4 years for those without adenoviruses; this difference remained significant (P = .008) after controlling for differences in CD4 counts between the groups. Gastrointestinal adenovirus excretion occurs at an advanced stage of HIV disease, and is associated with a poor prognosis. We suggest that adenoviruses may contribute to mortality in this population.

Adenovirus colitis in human immunodeficiency virus infection: an underdiagnosed entity

Adenovirus infection of the gastrointestinal tract in human immunodeficiency virus (HIV)-infected patients is rarely reported, probably because of a lack of familiarity of most pathologists with diagnostic criteria during routine light microscopy and possible misidentification as cytomegalovirus infection. We studied colonoscopic biopsy specimens from 135 HIV-infected patients with clinically suspected cytomegalovirus colitis during a 4.5-year period to morphologically identify the presence of adenovirus infection. Immunohistochemical staining for adenovirus was performed for confirmation on all suspected cases. Adenovirus infected cells showed characteristic amphophilic or eosinophilic nuclear inclusions, predominantly affecting the surface epithelium and characteristically involving goblet cells. Sixteen cases showed morphologic features of adenovirus infection, all confirmed by immunohistochemistry. Twelve cases also showed cytomegalovirus infection, whereas 4 showed adenovirus alone. In 10 cases, adenovirus colitis was not recognized during initial routine histopathologic diagnostic evaluation. Adenovirus inclusions also were discovered in the stomach, the duodenum, and the liver in single cases. Conclusions are as follows: (1) Adenovirus colitis has been underdiagnosed at our institution and, we suspect, in general. (2) The morphologic features and nuclear inclusions of adenovirus colitis are characteristic and can be identified reliably by routine light microscopy. (3) Adenovirus infection also may be diagnosed morphologically in extracolonic sites, such as the stomach, the small intestine, and the liver. (4) Coinfection of adenovirus with cytomegalovirus and other agents is seen frequently, but, less frequently, adenovirus may be identified as a sole pathogen.

Cognitive impairment after acute encephalitis: comparison of herpes simplex and other aetiologies

OBJECTIVE

To compare the cognitive defects after acute acyclovir treated herpes simplex encephalitis with those after other types of acute encephalitis.

METHODS

Seventy seven consecutive patients between 1985 and 1995 and 29 normal controls were studied. Of the 77 patients without concomitant neurological conditions, 17 had herpes simplex, one virus encephalitis (HSVE group), 27 had some other identified aetiology (non-HSVE group), and in 33 patients the cause was unknown. Acyclovir treatment was started less than four days after the first mental symptoms in 12 of 17 patients with HSVE. A thorough neuropsychological assessment was carried out about one month after the onset.

RESULTS

The HSVE group had deficits in verbal memory, verbal-semantic functions, and visuoperceptual functions more often than the non-HSVE group. The risk for cognitive defects was twofold to four-fold in the patients with HSVE compared with the non-HSVE patients. Two (12%) of the patients with HSVE and 12 (44%) of the non-HSVE patients were cognitively intact. Six patients with HSVE (46%) and 17 (89%) non-HSVE patients later returned to work. The lesions on CT or MRI were bilateral only in one patient with HSVE. The defects in the three patients with adenovirus infection were severe and resembled the amnesia after HSVE. Cognitive impairment, not previously reported, was found in encephalitis after rotavirus infection and epidemic nephropathy.

CONCLUSION

The recovery in the HSVE group was better than expected based on the medical literature. On the other hand there were surprisingly severe cognitive defects in encephalitis after other viruses. With early acyclovir treatment patients with the least severe HSVE were equivalent to those with non-HSV encephalitis with good outcome whereas those with the most severe non-HSV encephalitis were equivalent to those with HSVE with poor outcome.

Adenoviral-mediated thymidine kinase gene transfer into the primate brain followed by systemic ganciclovir: pathologic, radiologic, and molecular studies

Transduction of experimental gliomas with the herpes simplex virus thymidine kinase gene (HSV-tk) using a replication-defective adenoviral vector (ADV/RSV-tk) confers sensitivity to ganciclovir (GCV) leading to tumor destruction and prolonged host survival in rodents. To determine treatment tolerance prior to clinical trials, we conducted toxicity studies in 6 adult baboons (Papio sp.). The animals received intracerebral injections of either a high dose of ADV/RSV-tk [1.5 x 10(9) plaque-forming units (pfu)] with or without GCV, or a low dose of ADV/RSV-tk (7.5 x 10(7) pfu) with GCV. The low dose corresponded to the anticipated therapeutic dose; the high dose was expected to be toxic. Magnetic resonance imaging (MRI) of the brain was obtained before treatment and at 3 and 6 weeks after treatment. Animals receiving the high-dose vector and GCV either died or became moribund and required euthanasia during the first 8 days of treatment. Necropsies revealed cavities of coagulative necrosis at the injection sites. Animals receiving only the high-dose vector were clinically normal; however, lesions were detected with MRI at the injection sites corresponding to cystic cavities at necropsy. Animals receiving the low-dose vector and GCV were clinically normal, exhibited small MRI abnormalities, and, although no gross lesions were present at necropsy, microscopic foci of necrosis were present. The vector sequence was detected by polymerase chain reaction (PCR) at the injection sites and in non-adjacent central nervous system tissue in all animals. Recombinant DNA sequence was detected outside of the nervous system in some animals, and persisted up to 6 weeks. The viral vector injections stimulated the production of neutralizing antibodies in the animals. No shedding of the vector was found in urine, feces, or serum 7 days after intracerebral injection. This study suggests that further investigations including clinical toxicity trials of this form of brain tumor therapy are warranted.

Adenovirus mixture isolated from the brain of an AIDS patient with encephalitis

A mixture of adenoviruses 31 and 49 was isolated from the brain of an AIDS patient with encephalitis. Adenovirus hexon protein was detected in neurons by indirect immunofluorescence. By restriction endonuclease analysis both adenovirus 31 and 49 were shown to be new genotypes. This is the first report of the isolation of a mixture of adenoviruses from adenovirus encephalitis and the first association of adenovirus 49, a new candidate serotype, with encephalitis.

Adenoviruses in the immunocompromised host

Adenoviruses are among the many pathogens and opportunistic agents that cause serious infection in the congenitally immunocompromised, in patients undergoing immunosuppressive treatment for organ and tissue transplants and for cancers, and in human immunodeficiency virus-infected patients. Adenovirus infections in these patients tend to become disseminated and severe, and the serotypes involved are clustered according to the age of the patient and the nature of the immunosuppression. Over 300 adenovirus infections in immunocompromised patients, with an overall case fatality rate of 48%, are reviewed in this paper. Children with severe combined immunodeficiency syndrome and other primary immunodeficiencies are exposed to the serotypes of subgroups B and C that commonly infect young children, and thus their infections are due to types 1 to 7 and 31 of subgenus A. Children with bone marrow and liver transplants often have lung and liver adenovirus infections that are due to an expanded set of subgenus A, B, C, and E serotypes. Adults with kidney transplants have viruses of subgenus B, mostly types 11, 34, and 35, which cause cystitis. This review indicates that 11% of transplant recipients become infected with adenoviruses, with case fatality rates from 60% for bone marrow transplant patients to 18% for renal transplant patients. Patients with AIDS become infected with a diversity of serotypes of all subgenera because their adult age and life-style expose them to many adenoviruses, possibly resulting in antigenically intermediate strains that are not found elsewhere. Interestingly, isolates from the urine of AIDS patients are generally of subgenus B and comprise types 11, 21, 34, 35, and intermediate strains of these types, whereas isolates from stool are of subgenus D and comprise many rare, new, and intermediate strains that are untypeable for practical purposes. It has been estimated that adenoviruses cause active infection in 12% of AIDS patients and that 45% of these infections terminate in death within 2 months. In all immunocompromised patients, generalized illness involving the central nervous system, respiratory system, hepatitis, and gastroenteritis usually have a fulminant course and result in death. Treatments for adenovirus infections are of little proven value, although certain purine and pyrimidine analogs have shown beneficial effects in vitro and may be promising drugs.

Fatal adenovirus meningoencephalitis in a bone marrow transplant patient

We describe a bone marrow transplant patient with fatal subacute adenovirus meningoencephalitis, the first such patient reported. Neuropathological examination revealed unique, bilaterally symmetrical degeneration in the inferomedial temporal cortex, amygdaloid nuclei, hippocampi, hypothalamus, and some brainstem nuclei. Viral intranuclear inclusions were noted in these areas by light microscopy and confirmed by electron microscopy. Identification was authenticated by viral culture and the isolation of adenovirus from cerebral cortical tissues, and further confirmed by immunofluorescence and serological methods.

Opportunistic central nervous system pathology in patients with AIDS

Central nervous system disease related to the acquired immunodeficiency syndrome (AIDS) includes both those illnesses arising from primary human immunodeficiency virus infection and those secondary to opportunistic processes. Ten percent of AIDS patients present with neurological illness; nearly 40% have significant neurological symptoms and 75% have neuropathological abnormalities on autopsy. The frequency of multiple central nervous system pathological processes in the neurologically symptomatic AIDS patient may approach 30%, making the diagnosis and follow-up of these patients extremely difficult. Specific AIDS-related opportunistic infections of the central nervous system are discussed.