Clinical manifestations, prognostic factors, and outcomes of adenovirus pneumonia after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Severe pneumonia is one of the most important causes of mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Adenovirus (ADV) is a significant cause of severe viral pneumonia after allo-HSCT, and we aimed to identify the clinical manifestations, prognostic factors, and outcomes of ADV pneumonia after allo-HSCT.

METHODS

Twenty-nine patients who underwent allo-HSCT at the Peking University Institute of Hematology and who experienced ADV pneumonia after allo-HSCT were enrolled in this study. The Kaplan-Meier method was used to estimate the probability of overall survival (OS). Potential prognostic factors for 100-day OS after ADV pneumonia were evaluated through univariate and multivariate Cox regression analyses.

RESULTS

The incidence rate of ADV pneumonia after allo-HSCT was approximately 0.71%. The median time from allo-HSCT to the occurrence of ADV pneumonia was 99 days (range 17-609 days). The most common clinical manifestations were fever (86.2%), cough (34.5%) and dyspnea (31.0%). The 100-day probabilities of ADV-related mortality and OS were 40.4% (95% CI 21.1%-59.7%) and 40.5% (95% CI 25.2%-64.9%), respectively. Patients with low-level ADV DNAemia had lower ADV-related mortality and better OS than did those with high-level (≥ 106 copies/ml in plasma) ADV DNAemia. According to the multivariate analysis, high-level ADV DNAemia was the only risk factor for intensive care unit admission, invasive mechanical ventilation, ADV-related mortality, and OS after ADV pneumonia.

CONCLUSIONS

We first reported the prognostic factors and confirmed the poor outcomes of patients with ADV pneumonia after allo-HSCT. Patients with high-level ADV DNAemia should receive immediate and intensive therapy.

Epidemiological and molecular characterization of a novel adenovirus of squirrel monkeys after fatal infection during immunosuppression

Adenoviruses are a frequent cause of acute upper respiratory tract infections that can also cause disseminated disease in immunosuppressed patients. We identified a novel adenovirus, squirrel monkey adenovirus 1 (SqMAdV-1), as the cause of fatal infection in an immunocompromised squirrel monkey (Saimiri boliviensis) at the Keeling Center for Comparative Medicine and Research (KCCMR). Sequencing of SqMAdV-1 revealed that it is most closely related (80.4 % pairwise nucleotide identity) to the titi monkey (Plecturocebus cupreus) adenovirus (TMAdV). Although identified in the titi monkey, TMAdV is highly lethal in these monkeys, and they are not thought to be the natural host. While SqMAdV-1 is similar to other primate adenoviruses in size and genomic characteristics, a nucleotide polymorphism at the expected stop codon of the DNA polymerase gene results in a 126 amino acid extension at the carboxy terminus, a feature not previously observed among other primate adenoviruses. PCR testing and partial sequencing of 95 archived faecal samples from other squirrel monkeys (Saimiri boliviensis and Saimiri sciureus) housed at the KCCMR revealed the presence of three distinct, and apparently endemic species of adenoviruses. A grouping of ten squirrel monkey adenovirus variants has high similarity to SqMAdV-1. A single adenovirus variant (designated SqMAdV-3), detected in five monkeys, has similarity to tufted capuchin (Sapajus apella) adenoviruses. The largest group of adenovirus variants detected (designated SqMAdV-2.0-2.16) has very high similarity (93-99 %) to the TMAdV, suggesting that squirrel monkeys may be the natural host of the TMAdV.

Adenovirus Type 7 Pneumonia in Children Who Died from Measles-Associated Pneumonia, Hanoi, Vietnam, 2014

During a 2014 measles outbreak in Vietnam, postmortem pathologic examination of hospitalized children who died showed that adenovirus type 7 pneumonia was a contributory cause of death in children with measles-associated immune suppression. Adenovirus type 7 pneumonia should be recognized as a major cause of secondary infection after measles.

Interferon-dependent immunoproteasome activity during mouse adenovirus type 1 infection

The immunoproteasome is an inducible host mechanism that aids in the clearance of damaged proteins. The immunoproteasome also influences immune function by enhancing peptide presentation by MHC class I and promotes inflammation via IκB degradation and activation of NF-κB. We used mouse adenovirus type 1 (MAV-1) to characterize the role of the immunoproteasome in adenovirus pathogenesis. Following intranasal infection of mice, immunoproteasome activity in the heart and lung was significantly increased in an IFN-γ-dependent manner. Absence of the β5i immunoproteasome subunit and pharmacological inhibition of β5i activity had minimal effects on viral replication, virus-induced cellular inflammation, or induction of cytokine expression. Likewise, the establishment of protective immunity following primary infection was not significantly altered by β5i deficiency. Thus, although immunoproteasome activity is robustly induced during acute infection with MAV-1, our data suggest that other mechanisms are capable of compensating for immunoproteasome activity to maintain antiviral immunity and appropriate inflammatory responses.

[Etiology of fatal pneumonia caused by influenza A(H1N1)pdm2009 virus during the pandemic in Russia]

The results of the study of the autopsy materials from 61 patients with the diagnosis of pneumonia received by virological and genetic methods are reviewed. The materials were studied at the Influenza Etiology and Epidemiology Center of the Ivanovsky Institute of Virology, Ministry of Health and Social Development of the Russian Federation, during epidemic seasons 2009-2010 and 2010-2011. The data were analyzed with respect to age, sex, comorbidity diseases and identified on the groups of the risk of severe forms of the disease. The presence of the pandemic influenza virus strain RNA was confirmed in 70.5% of materials; RNA of influenza B was detected in 1.2% cases. The co-infections caused by the bocavirus, adenovirus, parainfluenza virus type 2 and 4, rhinovirus, and streptococcus were detected only in 19.7%. In most cases, the influenza virus was the etiologic agent of lethal pneumonia, which justifies the necessity of the early etiological diagnosis and treatment with antiviral drugs.

Safety and efficacy of CMX001 as salvage therapy for severe adenovirus infections in immunocompromised patients

No therapeutic agent has yet been established as the definitive therapy for adenovirus infections. We describe the clinical experience of 13 immunocompromised patients who received CMX001 (hexadecyloxypropyl cidofovir), an orally bioavailable lipid conjugate of cidofovir, for adenovirus disease. We retrospectively analyzed 13 patients with adenovirus disease and viremia treated with CMX001; data were available for ≥ 4 weeks after initiation of CMX001 therapy. Virologic response (VR) was defined as a 99% drop from baseline or undetectable adenovirus DNA in serum. The median age of the group was 6 years (range, 0.92-66 years). One patient had severe combined immunodeficiency, 1 patient was a small bowel transplant recipient, and 11 were allogeneic stem cell transplant recipients. Adenovirus disease was diagnosed at a median of 75 days (range, 15-720 days) after transplantation. All patients received i.v. cidofovir for a median of 21 days (range, 5-90 days) before CMX001 therapy. The median absolute lymphocyte count at CMX001 initiation was 300 cells/μL (range, 7-1500 cells/μL). Eight patients (61.5%) had a ≥ 1 log10 drop in viral load after the first week of therapy. By week 8, 9 patients (69.2%) demonstrated a VR, with a median time to achieve VR of 7 days (range, 3-35 days). The change in absolute lymphocyte count was inversely correlated with the change in log10 viral load only at week 6 (r = -0.74; P = .03). Patients with VR had longer survival than those without VR (median 196 days versus 54.5 days; P = .04). No serious adverse events were attributed to CMX001 during therapy. CMX001 may be a promising therapeutic option for the treatment of severe adenovirus disease in immunocompromised patients.

Adenoviral Infections in Hematopoietic Stem Cell Transplantation

Adenoviruses are lytic DNA viruses that are ubiquitous in human communities. In total, 51 different serotypes with varying tissue tropisms have been identified. Adenovirus infections, although frequent, are rarely fatal in immunocompetent individuals who have potent innate and adaptive immunity. But in immunosuppressed individuals, adenoviruses are a significant cause of morbidity and mortality, with limited treatment options. In particular, pediatric recipients of allogeneic hematopoietic stem cell transplantation frequently develop infections early in the posttransplantation period. Because the endogenous recovery of adenovirus-specific T cells has proven important in controlling infection, we explore the potential of adoptive T-cell immunotherapy as a therapeutic strategy. We discuss the advantages and limitations of T-cell therapy for the prophylaxis and treatment of adenovirus infection posttransplantation.

Risk assessment of adenoviruses detected in treated drinking water and recreational water

AIMS

Human adenoviruses (HAds) have previously been detected in sewage and polluted river and dam water, as well as treated drinking water. The 51 serotypes of HAds cause a wide range of infections with clinical manifestations associated with the gastrointestinal, respiratory and urinary tracts, and the eyes. Water may play a meaningful role in the transmission of many of these HAd serotypes, specifically the enteric HAds which are transmitted via the faecal-oral route. The presence of these viruses in water used for drinking and recreational purposes is considered to constitute a potential health risk. In this study, the risk of infection by the group of HAds previously detected over a period of 1 year in selected drinking water supplies, as well as river and dam water used for recreational purposes, was assessed.

METHODS AND RESULTS

Adenoviruses were previously detected in nine of 204 (4.41%) samples of two drinking water supplies (A and B) treated and disinfected according to international specifications, in four of 51 (7.8%) samples of river water and nine of 51 (17.7%) samples of dam water. Application of these previously published results in an exponential risk assessment model indicated an annual risk of infection of 1.01 x 10(-1) and 1.7 x 10(-1) for drinking water supplies A and B, respectively, assuming a daily consumption of 2 l day(-1). The daily risk of infection constituted by HAds in the river water was calculated as 1.71 x 10(-4), and in the dam water as 3.12 x 10(-5), assuming a consumption of 30 ml of water per day.

CONCLUSIONS

The risk of infection exceeded the tolerable risk of one infection per 10 000 consumers per year proposed for drinking water. However, the results for river and dam water used for recreational purposes were within the tolerable risk of one infection per 1000 bathers per day proposed for environmental waters used for recreational purposes.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study showed that the risk of HAd infection calculated for the drinking water supplies and the recreational water may overestimate the actual risk of infection, as conservative values were assumed for some of the variables. For a more accurate assessment of the potential risk of infection research should at least include a thorough investigation of the water consumption of individuals in South Africa, and the efficiency of recovery of the glass wool adsorption-elution method.

Human herpesvirus 6 in bronchalveolar lavage fluid after lung transplantation: a risk factor for bronchiolitis obliterans syndrome?

Bronchiolitis obliterans syndrome (BOS) is the limiting factor to long-term survival after lung transplantation. Previous studies suggested respiratory viral tract infections are associated with the development of BOS. To identify the impact of virus detection in bronchoalveolar lavage (BAL) fluid, we analyzed BAL samples from 87 consecutive lung transplant recipients for human herpesvirus (HHV)-6, Epstein-Barr virus, Herpes simplex virus 1/2, Cytomegalovirus, respiratory syncytical virus and adenovirus by PCR. Acute rejection, BOS and death were recorded for a mean follow-up time of 3.27 +/- 0.47 years. Results of PCR analysis and other potential risk factors were entered into a Cox regression analysis of BOS predictors and death. Only acute rejection was a distinct risk factor for BOS of all stages, death and death from BOS. HHV-6 was detected in 20 patients. Univariate and multivariate analysis revealed that HHV-6 was associated with an increased risk to develop BOS > orb = stage 1 and death, separate from the risk attributable to acute rejection. Identification of HHV-6 DNA in BAL fluid is a potential risk factor for BOS. Our results warrant further studies to elucidate a possible causal link between HHV-6 and BOS.

T-Cell Immunotherapy for Adenoviral Infections of Stem-Cell Transplant Recipients

Human adenoviruses are ubiquitous lytic DNA viruses that can be divided into 51 different serotypes, grouped from A to F on the basis of genome size, composition, homology, and organization. Adenovirus infections, although frequent, are rarely fatal in immunocompetent individuals, due to potent innate and adaptive immune responses. By contrast, adenoviruses are a significant cause of morbidity and mortality in immunosuppressed individuals, for whom there are limited treatment options. Since antiviral drugs have variable efficacy in the treatment of severe adenovirus disease, iatrogenic reconstitution with in vitro expanded virus-specific cytotoxic T lymphocytes (CTLs) is an attractive option for prophylaxis and treatment, particularly because the endogenous recovery of adenovirus-specific T cells has proved important in controlling infection in vivo. Thus, we have characterized human T-cell responses to adenovirus in vitro and explored the potential of adoptive T-cell immunotherapy as a prophylactic or therapeutic strategy for adenovirus infections posttransplant.

Evaluation of toxicity from high-dose systemic administration of recombinant adenovirus vector in vector-naïve and pre-immunized mice

Toxicity associated with in vivo administration of adenovirus (Ad) vectors has been linked to activation of both innate and adaptive immune responses. Pre-existing immunity to the prevalent Ad serotypes, acquired by the majority of the human population as a result of natural infections, has the potential to modulate vector efficacy and safety. Previously, we evaluated some aspects of toxicity from systemic Ad vector in vector-naive and pre-immunized rhesus monkeys. In this report, we summarize data from several studies analyzing toxic effects from systemically administered E1/E3-deleted Ad vector in vector-naive and pre-immunized C57BL/6 mice. Our results indicate that pre-immunization can be associated with increased mortality shortly after systemic administration of Ad. Transient leukopenia and thrombocytopenia were observed early post vector infusion in both vector-naive and pre-immunized animals. Pre-exposure to the vector did not prevent induction of pro-inflammatory cytokines; however, pre-immunized mice showed less tissue toxicity. Growth of bone marrow myeloid and erythroid progenitors was transiently inhibited in pre-immunized animals, but only the myeloid progenitors were affected in vector-naive animals. In summary, pre-existing immunity to Ad vector substantially modifies host immune responses to systemic Ad vector.

Incidence and outcome of adenovirus disease in transplant recipients after reduced-intensity conditioning with alemtuzumab

Adenoviruses are emerging as a major cause of infectious complications after allogeneic transplantation. We evaluated the incidence and outcome of symptomatic adenovirus infection or adenovirus disease after alemtuzumab-based reduced-intensity conditioning in 86 consecutive patients. The overall probability of adenovirus disease was 18.4% (11/86 patients). Five patients died of progressive adenovirus disease, and this was the most important infectious cause of mortality in this cohort. The probability of nonrelapse mortality was 49% in patients with adenovirus disease compared with 25.5% in those without (P=.007). The severity of lymphocytopenia and continuation of immunosuppressive therapy were the most important risk factors for progressive adenovirus disease and death. In contrast, patients who were not receiving immunosuppressive therapy or had had it reduced or withdrawn cleared the virus. We also detected a correlation between the lack of preemptive anti-cytomegalovirus (CMV) therapy for CMV reactivation and the risk of progressive adenovirus disease (P=.05). Our findings highlight the emergence of adenovirus as an important posttransplantation pathogen even after reduced-intensity conditioning and demonstrate the effect of the severity of lymphocytopenia, anti-CMV prophylaxis, and immunosuppressive therapy on the outcome of adenovirus disease.

Canine distemper and related diseases: report of a severe outbreak in a kennel

An outbreak of canine distemper in a kennel of German shepherds in the province of Bari is reported. Six 42-day-old pups developed typical signs of canine distemper (fever, conjunctivitis, respiratory distress and enteritis) and died within 7-10 days. Neurological symptoms were observed only in one pup. Four additional pups, which had shown no sign of illness, were separated and vaccinated, but two of these developed a severe, fatal nervous form 15 days later. Post-mortem examination, carried out on two pups which died without neurological signs, showed pneumonia and enteritis, more severe in one of the two examined pups. Smears from the brain and the conjunctiva of both dogs tested positive for canine distemper virus (CDV) by an immunofluorescent assay, confirmed by the identification of viral RNA using RT-PCR. Bordetella bronchiseptica and a canine adenovirus strain, characterized as canine adenovirus type 2 by a differential PCR assay, were isolated from the lungs of the pup showing the most pronounced lesions. Furthermore, canine coronavirus was detected by PCR in the intestinal content of this pup, suggesting a multifactorial aetiology of the outbreak.

Fatal Type 3 Adenoviral Pneumonia in Immunocompetent Adult Identical Twins

We describe adult twin sisters who developed severe adenoviral pneumonia with relative leukopenia, progressive focal infiltrates, shock, and hypoxia. Potential determinants of severe adenoviral disease are discussed.

An Adenovirus Linked to Mortality and Disease in Long-Tailed Ducks (Clangula hyemalis) in Alaska

An adenovirus was isolated from intestinal samples of two long-tailed ducks (Clangula hyemalis) collected during a die-off in the Beaufort Sea off the north coast of Alaska in 2000. The virus was not neutralized by reference antiserum against known group I, II, or III avian adenoviruses and may represent a new serotype. The prevalence of the virus was determined in live-trapped long-tailed ducks at the mortality site and at a reference site 100 km away where no mortality was observed. Prevalence of adenovirus antibodies in serum samples at the mortality site was 86% compared to 10% at the reference site. Furthermore, 50% of cloacal swabs collected at the mortality site and only 7% of swabs from the reference site were positive for adenoviruses. In 2001, no mortality was observed at either of the study areas, and virus prevalence in both serum and cloacal samples was low, providing further evidence that the adenovirus was linked to the mortality event in 2000. The virus was used to infect long-tailed ducks under experimental conditions and resulted in lesions previously described for avian adenovirus infections and similar to those observed in long-tailed duck carcasses from the Beaufort Sea. The status of long-tailed ducks has recently become a concern in Alaska due to precipitous declines in breeding populations there since the mid-1970s. Our findings suggest that the newly isolated adenovirus is a disease agent and source of mortality in long-tailed ducks, and thus could be a contributing factor in population declines.

Adenovirus infection in hematopoietic stem cell transplantation: effect of ganciclovir and impact on survival

Adenoviruses (ADV) are emerging as important causes of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). In mainly non-T-cell depleted HSCT recipients, we analyzed the incidence of ADV infection, risk factors for infection, the effect of ganciclovir administered for prevention of cytomegalovirus (CMV), and the impact of ADV infection on survival. The overall incidence of ADV, irrespective of the method of detection, was 8.5% (450/5233) and 12.3% (43/348) after the first or second allogeneic HSCT, and 6.3% (78/1219) and 6.5% (5/77) after the first or second autologous HSCT, respectively. The most frequent sites of infection and disease were stool and gastrointestinal tract, respectively. Statistically significant risk factors associated with ADV infections among allogeneic recipients included younger age, grade II to IV graft-versus-host disease, year of transplantation, and a second allogeneic HSCT. Furthermore, allogeneic patients seronegative for CMV at transplantation and seropositive allogeneic patients who did not receive ganciclovir, either at engraftment or as pre-emptive therapy on CMV reactivation, were at higher risk of developing ADV infections compared with seropositive patients who received ganciclovir (odds ratio=1.8, 95% confidence interval (CI) 1.2 to 2.8, P=.005 and odds ratio=3.4, 95% CI 2.1 to 5.55, P<.0001, respectively). The hazard of overall mortality was higher in patients who contracted ADV compared with those who did not (hazard ratio 1.5, 95% CI 1.3 to 1.7, P<.0001). This study shows that ADV infections are associated with poor transplantation outcome in T-cell repleted HSCT recipients. Ganciclovir, given for CMV prevention, may have a protective effect. Controlled treatment and prevention studies are warranted.

An adenovirus associated with intestinal impaction and mortality of male common eiders (Somateria mollissima) in the Baltic Sea

We examined 10 common eider (Somateria mollissima) males found dead in 1998 during a die-off in the northern Baltic Sea off the southwestern coast of Finland. We diagnosed impaction of the posterior small intestine with mucosal necrosis as the cause of death in all 10 and isolated adenoviruses from cloacal samples of six birds. The adenovirus isolates were not neutralized by reference antisera to group I, II, or III avian adenoviruses. Cloacal swabs from 22 apparently healthy eider females nesting at the mortality area were negative for viruses. An adenovirus isolated from one of the eiders caused clinical signs of illness and gastrointestinal pathology in experimentally infected mallard (Anas platyrhynchos) ducklings. These findings suggest that the adenovirus contributed to the mortality of common eider males in the Finnish archipelago.

Cytomegalovirus and adenovirus infections and diseases among 75 paediatric unrelated allogeneic bone marrow transplant recipients

Viral infections remain a major complication of allogeneic bone marrow transplantation. A population of children who underwent unrelated allogeneic bone marrow transplantation in a single centre has been followed-up for viral infections and diseases. We describe the detection of cytomegalovirus (CMV) and adenovirus among 75 children transplanted between 1989 and 2000. CMV was detected among 22 patients (29%) and adenovirus among 19 patients (25%); they were associated with clinical diseases in 10 and 8 patients, respectively. Four patients had adenovirus and CMV coinfection. The obvious risk factor for CMV infection is seropositivity of the recipient prior to transplantation. Adenovirus is detected significantly more frequently when conditioning regimen includes anti-thymocyte or anti-lymphocyte globulin. Diseases associated with adenovirus have been correlated with a significantly higher mortality rate, stressing the need for the implementation of a systematic virological survey for this virus and for the evaluation of therapeutic protocols including new molecules.

Lack of interaction between avian leukosis virus subgroup J and fowl adenovirus (FAV) in FAV-antibody-positive chickens

Unfounded field speculation has suggested that avian leukosis virus subgroup J (ALV-J) predisposes young meat-type chickens to inclusion body hepatitis caused by fowl adenovirus (FAV). To address this hypothesis, we infected 1-day-old grandparent meat-type chickens carrying maternal antibodies against FAV with a field isolate of FAV associated with inclusion body hepatitis in broilers, ALV-J, or both FAV and ALV-J. We examined the effects of FAV alone or in combination with ALV-J on the basis of clinical signs, overall mortality, growth rate, and gross and microscopic lesions. With such criteria for evaluating possible interactions, we found no significant differences in the dually infected birds in comparison with chickens that received a monovalent challenge with either FAV or ALV-J.

High levels of adenovirus DNA in serum correlate with fatal outcome of adenovirus infection in children after allogeneic stem-cell transplantation

An increase in the incidence of adenovirus (AdV) infection leading to death among children who have undergone allogeneic stem-cell transplantation has made it necessary to find new ways to monitor AdV infection. In this retrospective study, levels of AdV DNA in serum samples obtained from 36 transplant recipients with stool cultures positive for AdV were measured by polymerase chain reaction (PCR) semiquantitatively by analyzing serial dilutions of the DNA template. Six (86%) of 7 children who died of AdV infection, compared with only 2 (7%) of 29 other patients, had high serum levels of AdV DNA (detectable by PCR at a > or =100-fold dilution of the DNA template; P<.0001). High serum levels of AdV DNA were reached a mean of 18 days before death (range, 6-29 days). Quantification of adenoviral DNA in serum may prove to be a valuable tool to diagnose and monitor AdV infection and disease in immunocompromised children.

Adenovirus type 7 associated with severe and fatal acute lower respiratory infections in Argentine children

BACKGROUND

Adenoviruses are the second most prevalent cause of acute lower respiratory infection of viral origin in children under four years of age in Buenos Aires, Argentina. The purpose of this study was to analyze the clinical features and outcome of acute lower respiratory infection associated with different adenovirus genotypes in children.

METHODS

Twenty-four cases of acute lower respiratory infection and adenovirus diagnosis reported in a pediatric unit during a two-year period were retrospectively reviewed. Adenovirus was detected by antigen detection and isolation in HEp-2 cells. Adenovirus DNA from 17 isolates was studied by restriction enzyme analysis with Bam HI and Sma I.

RESULTS

Subgenus b was found in 82.3% of the cases, and subgenus c in 17.7%. Within subgenus b, only genotype 7 was detected, with genomic variant 7h in 85.7% (12/14) and genomic variant 7i in 14.3% (2/14). Mean age was 8.8 +/-; 6 months, and male to female ratio was 3.8: 1. At admission, pneumonia was observed in 71% of the cases and bronchiolitis in 29%. Malnutrition occurred in 37% of the cases; tachypnea in 79%; chest indrawing in 66%; wheezing in 58%; apneas in 16%; and conjunctivitis in 29%. Blood cultures for bacteria and antigen detection of other respiratory viruses were negative. During hospitalization, fatality rate was 16.7% (4 /24). Of the patients who died, three had Ad 7h and one Ad 7i. Thus, fatality rate for adenovirus type 7 reached 28.6% (4/14).

CONCLUSIONS

These results show the predominance of adenovirus 7 and high lethality associated with the genomic variants 7h and 7i in children hospitalized with acute lower respiratory infection.

Intravenous ribavirin treatment for severe adenovirus disease in immunocompromised children

BACKGROUND

Adenovirus is an important cause of morbidity and mortality in the immunocompromised host. The incidence of severe adenovirus disease in pediatrics is increasing in association with growing numbers of immunocompromised children, where case fatality rates as high as 50% to 80% have been reported. There are no approved antiviral agents with proven efficacy for the treatment of severe adenovirus disease, nor are there any prospective randomized, controlled trials of potentially useful anti-adenovirus therapies. Apparent clinical success in the treatment of severe adenovirus disease is limited to a few case reports and small series. Experience is greatest with intravenous ribavirin and cidofovir. Ribavirin, a guanosine analogue, has broad antiviral activity against both RNA and DNA viruses, including documented activity against adenovirus in vitro. Ribavirin is licensed in aerosol form for the treatment of respiratory syncytial virus infection, and orally in combination with interferon to treat hepatitis C. Intravenous ribavirin is the treatment of choice for infection with hemorrhagic fever viruses. The most common adverse effect of intravenous ribavirin is reversible mild anemia. The use of cidofovir in severe adenovirus infection has been limited by adverse effects, the most significant of which is nephrotoxicity.

OBJECTIVE

We report our experience with intravenous ribavirin therapy for severe adenovirus disease in a series of immunocompromised children and review the literature.

DESIGN/METHODS

We retrospectively reviewed the medical records of 5 children treated with intravenous ribavirin for documented severe adenovirus disease. Two patients developed adenovirus hemorrhagic cystitis after cardiac and bone marrow transplants, respectively. The bone marrow transplant patient also received intravenous cidofovir for progressive disseminated disease. An additional 3 children developed adenovirus pneumonia; 2 were neonates, 1 of whom had partial DiGeorge syndrome. The remaining infant had recently undergone a cardiac transplant. Intravenous ribavirin was administered on a compassionate-use protocol.

RESULTS

Complete clinical recovery followed later by viral clearance was observed in 2 children: the cardiac transplant recipient with adenovirus hemorrhagic cystitis and the immunocompetent neonate with adenovirus pneumonia. The remaining 3 children died of adenovirus disease. Intravenous ribavirin therapy was well tolerated. Use of cidofovir in 1 child was associated with progressive renal failure and neutropenia.

DISCUSSION

Our series of patients is representative of the spectrum of immunocompromised children at greatest risk for severe adenovirus disease, namely solid-organ and bone marrow transplant recipients, neonates, and children with immunodeficiency. Although intravenous ribavirin was not effective for all children with severe adenovirus disease in this series or in the literature, therapy is unlikely to be of benefit if begun late in the course of the infection. Early identification, eg by polymerase chain reaction of those patients at risk of disseminated adenovirus disease may permit earlier antiviral treatment and better evaluation of therapeutic response.

CONCLUSIONS

Two of 5 children with severe adenovirus disease treated with intravenous ribavirin recovered. The availability of newer rapid diagnostic techniques, such as polymerase chain reaction, may make earlier, more effective treatment of adenovirus infection possible. Given the seriousness and increasing prevalence of adenovirus disease in certain hosts, especially children, a large, multicenter clinical trial of potentially useful anti-adenoviral therapies, such as intravenous ribavirin, is clearly required to demonstrate the most effective and least toxic therapy.

Adenoviral infections and a prospective trial of cidofovir in pediatric hematopoietic stem cell transplantation

Adenoviral (ADV) infections are increasingly recognized as a cause of morbidity and mortality in pediatric hematopoietic stem cell transplantation (HSCT). We reviewed our experience with ADV infections in HSCT patients hospitalized for transplantation at Childrens Hospital Los Angeles January 1998 through December 1998. ADV was detected in 47% of patients, with recipients of HSCT from alternative donors (matched unrelated, unrelated cord, and mismatched related donors) being more frequently culture positive than recipients of HSCT from matched siblings (62% versus 27%, P = .04). Detection of ADV from 2 or more sites was associated with organ injury, eg, hemorrhagic cystitis, enteritis, and hepatitis. Because of the high incidence of ADV culture-positive patients and the lack of effective anti-ADV therapy, we initiated a prospective trial to evaluate cidofovir (CDV) in the treatment of ADV infections in HSCT recipients. Eight patients were enrolled on a dosage schedule of 1 mg/kg 3 times weekly. AD of these patients eventually achieved long-term viral suppression and clinical improvement, although 6 patients needed prolonged CDV therapy for up to 8 months before CDV could be stopped without ADV recurrence. We did not observe dose-limiting nephrotoxicity, and the discontinuation of the drug was not required in any patients. Prospective controlled trials to further define the role of CDV in the treatment of ADV infections in HSCT patients are warranted.

Proliferation of lung macrophages in acute fatal viral infections in chickens

Marked proliferation of macrophages engulfing yellow pigments and fragmented erythrocytes were seen in the air capillaries and blood capillaries of the lungs of chickens affected with acute fatal viral hydropericardium syndrome, highly pathogenic infectious bursal disease, and highly pathogenic avian influenza. Proliferation of lung macrophages was associated with systemic proliferation of macrophages. Acute destruction of erythrocytes in these infections may have induced systemic hyperplasia of macrophages. The acute and severe proliferation of lung macrophages may cause acute respiratory dysfunction and be one of the factors inducing mortality in infected chickens. This syndrome may be categorized as "virus-associated hemophagocytic syndrome."

Genomic identification and characterization of avian adenoviruses associated with inclusion body hepatitis

Four pathogenic avian adenovirus isolates associated with inclusion body hepatitis and mortality in commercial broiler chicks and chickens were characterized and identified. These group I avian adenovirus isolates were classified as group E (serotypes 6, 7, 8, and 9) avian adenoviruses on the basis of the restriction enzyme patterns of their viral DNA. Isolate 3718 was neutralized by a serotype 6 reference avian adenovirus antiserum and isolates 8193, 8380, and 8565 were all neutralized by a serotype 8 reference avian adenovirus antiserum by virus neutralization assays. Infectivity and virulence such as mortality, hemorrhages, enlarged green livers with intranuclear inclusion bodies, stunting, intestinal sloughing, and poor feathering were observed in specific-pathogen-free chicken embryos and were identical for all four isolates when embryos were inoculated via the yolk sac and/or chorioallantoic membrane. Complete mortality was observed within 72 hr postinoculation in specific-pathogen-free (SPF) chickens inoculated intramuscularly for all four avian adenovirus isolates.

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.

Isolation of fowl adenoviruses serotype 4 from pigeons with hepatic necrosis

Nine homogenized livers were taken to isolate the causative agent of adenovirus type I and type II infections in pigeons. The samples were passaged up to four times on primary chicken embryo hepatocytes. Adenoviruses were isolated from all of the six type II but none of the three type I infections. Serologically the isolated adenoviruses were classified as fowl adenovirus (FAV) serotype 4. Restriction enzyme analysis of two isolates in comparison with FAV4 reference strain KR5 confirmed the serological results and classification of the pigeon isolates as FAV4 strains.

Retrograde and anterograde labeling of cerebellar afferent projection by the injection of recombinant adenoviral vectors into the mouse cerebellar cortex

Adenoviral vectors have recently been recognized as highly efficient systems for gene delivery into various tissues. We show that a reporter gene introduced into nerve terminals via an adenovirus can be used to label cell bodies retrogradely and then label the axons and nerve terminals of the infected neurons anterogradely in vivo. We injected a replication-defective recombinant adenovirus carrying the E. coli beta-galactosidase gene (lacZ) into the cerebellar cortex of the adult mouse. The first evidence of retrograde labeling was obtained at 2 days after the infection when neurons in the pontine nuclei and the reticulotegmental nucleus of the pons weakly expressed beta-galactosidase, and at 3 days post-infection when neurons in all precerebellar nuclei, known to project to the cerebellar cortex, were strongly stained with X-gal in a Golgi-like manner. Anterograde transport of lacZ gene products was recognized at 3 days post-infection; beta-galactosidase-positive axons arose from somata or dendrites of retrogradely labeled neurons, passed through the middle or inferior cerebellar peduncles, and entered the cerebellum. Anterogradely labeled mossy terminals were recognized on the injection side at 8 days post-infection, and on the contralateral side at 14 days post-infection. Beta-galactosidase expression persisted for up to two months, with a decrease in the total number of labeled cells over time. We could not find any signs of anterograde or retrograde transsynaptic labeling in the nuclei synaptically linked to the cerebellar cortex at any time point after injection up to 58 days post-infection.

Characterization of an avian adenovirus associated with inclusion body hepatitis in day-old turkeys

A group I avian adenovirus isolated from day-old turkeys with inclusion body hepatitis (IBH) was identified as turkey adenovirus serotype 2 (TAV2) based on cross-neutralization assays and DNA restriction endonuclease analyses. Yolk sac inoculation of embryonated turkey eggs resulted in embryo mortality and significantly (P < 0.01) decreased hatchability compared with sham-inoculated controls. Embryo mortality occurred primarily between day 24 of incubation and the time embryos hatched. Focal necrosis was detected in livers of 11/52 virus-inoculated embryos that died postinoculation and 1/27 hatchlings; in three embryos, areas of necrosis contained intranuclear inclusion bodies. These findings identify the IBH isolate as TAV2, incriminate the virus as a potential cause of suboptimal hatchability in turkeys, and provide additional evidence for causal involvement in IBH.

Adenovirus-induced inclusion body hepatitis in four-day-old broiler breeders

Two separate parent broiler flocks originating from the same grandparent flock experienced mortalities of 23% and 40%, respectively, in chicks between 1 and 14 days of age. Chicks affected at 4 days of age had tremors, depression, and hypoglycemia. They had pale yellow, swollen, friable livers. Pancreata were discolored and hemorrhagic. Spleens were swollen and sightly darkened. Microscopic lesions consisted of multifocal areas of acute hepatic and pancreatic necrosis with numerous basophilic intranuclear inclusions with karyomegaly. Splenic sections had severe lymphoid depletion and reticular cell and macrophage hyperplasia. An adenovirus from affected livers was isolated in chicken embryo liver cells. Serologic evidence suggests that the grandparent flock began egg production seronegative to adenovirus antibodies, was exposed during production, and, subsequently, shed adenovirus vertically to its progeny. The clinical syndrome was reproduced by injecting the isolated adenovirus into 1-day-old antibody-negative chicks. Histologic lesions in the experimentally reproduced disease cases were identical to those in the naturally occurring cases.

Systemic adenovirus infection associated with high mortality in mule deer (Odocoileus hemionus) in California

Seventeen counties in northern California experienced epizootics of high mortality in the mule deer (Odocoileus hemionus) population during the latter half of 1993. Thirteen deer submitted to the California Veterinary Diagnostic Laboratory System as part of this natural die-off had systemic adenovirus infection. Pulmonary edema was present in all 13 deer. Erosions, ulceration, and abscessation of the upper alimentary tract occurred in 7/13 deer. Four of 13 deer had hemorrhagic enteritis. All 13 deer had widespread systemic vasculitis with endothelial intranuclear inclusions. Fluorescein isothiocyanate-labeled antibody directed against bovine adenovirus type 5 bound to antigen in endothelial cells. Adenovirus was identified by transmission electron microscopy within the nuclei of endothelial cells in 6/6 deer examined. An adenovirus was isolated from lung homogenates of one deer that were cultured on black-tailed deer pulmonary artery endothelial cells. With the exception of the intranuclear inclusions evident on histologic evaluation, gross and histologic changes were similar to those described for bluetongue virus infection and epizootic hemorrhagic disease virus infection in white-tailed deer. Nine additional deer were emaciated and had pharyngeal abscesses with focal vasculitis, which may represent the chronic affects of previous nonfatal adenovirus infection.

Expression of early and late adenoviral proteins in fatal adenovirus bronchopneumonia

The localization and distribution of three adenoviral proteins, hexon, E1A, and 55-kDa E1B, in 16 cases of fatal adenovirus bronchopneumonia in infants and children, are described. The proteins were immunohistochemically demonstrated in paraffin sections using monoclonal antibodies followed by the avidin-biotin-peroxidase method. The hexon antigen was present in inclusion-bearing bronchial, bronchiolar, and alveolar cells, mainly in the so-called rosette cells, as well as in necrotic debris in necrotizing areas. E1A antigen was also recognized in cells with nuclear inclusions where the reaction decorated the inclusion, nuclear chromatin, and cytoplasm but distributed mainly in alveolar cells and to a lesser extent in bronchial and bronchiolar cells. The 55-kDa E1B protein was extensively present in "activated," reactive-appearing, nuclei of bronchial, bronchiolar, and alveolar epithelial cells and in the cytoplasm of rare cells having nuclear inclusions. These activated nuclei did not stain for the other two antigens. "Smudge" cells reacted poorly or not at all with any of the antibodies. The reactivity found produced a sort of complementary pattern between the hexon-positive, inclusion-containing cells and the 55-kDa E1B-positive, inclusion-noncontaining cells. The relationships of present findings and virologic data are discussed.

Inclusion body hepatitis in Gambel's quail (Callipepla gambelii)

An acute necrotizing hepatitis in 1- to 3-wk-old Gambel's quail (Callipepla gambelii) caused by an adenovirus is described. The infection caused high mortality in captive raised, orphan chicks at two wildlife rehabilitation facilities in Arizona (USA). Gross lesions varied from pale livers to multiple, pinpoint, white foci scattered throughout the livers. Microscopically, scattered foci of hepatocellular necrosis were present. Intact hepatocytes at teh periphery of necrotic foci had eosinophilic and basophilic intranuclear inclusion bodies.

Experimental infection of bobwhite quail with Indiana C adenovirus

Bobwhite quails (Colinus virginianus) were inoculated intratracheally, intraperitoneally, or subcutaneously with Indiana C adenovirus at 1, 3, 6, or 9 weeks of age. Mortality rates were 33-100% in quails inoculated at 1 or 3 weeks of age and 0-10% in quails inoculated at 6 or 9 weeks of age. Gross and histologic lesions included necrotizing tracheitis and bronchitis with pneumonia, necrotizing hepatitis and splenitis, and lymphoid depletion of the bursa of Fabricius; these were consistent with quail bronchitis. Indiana C is highly pathogenic in bobwhite quails and cannot be recommended as a vaccine to prevent quail bronchitis.

Use of virulent hemorrhagic enteritis virus for the induction of colibacillosis in turkeys

Three hundred fifty 1-day-old large white turkeys were reared in brooding batteries to 10 days of age, after which they were moved to floor pens on litter. At 7 weeks of age, poults were allotted into four treatment groups as follows: 1) virulent hemorrhagic enteritis virus (HEV) alone (100 turkeys), 2) Escherichia coli alone (100 turkeys), 3) HEV + E. coli (100 turkeys), and 4) negative controls (50 turkeys). HEV was given orally at 7 weeks of age, followed by E. coli challenge in the drinking water 2 days later for 10 consecutive days. All groups were observed daily for mortality, both during and after challenge. Turkeys that died or were moribund were necropsied, and cultures were taken from the liver and bone marrow for bacterial isolation. Total mortality rates were 23% in the HEV + E. coli group, 10% in the HEV-only group, 3% in the E. coli-only group, and 0% in the negative control group. Cumulative mortality values were significantly different from those of the negative controls (P < or = 0.05) for HEV only and the HEV + E. coli group. E. coli was isolated from the liver and bone marrow of almost all turkeys that died.

Viral tracheitis in goslings in Saskatchewan

Up to 12% mortality occurred in goslings between 4 and 11 days of age in two sequential hatches from a single breeder flock. Respiratory signs were noted before the birds died. The most consistent necropsy finding was a white opaque plug of fibrin and cellular debris in the trachea. The tracheal epithelium was hyperplastic and metaplastic with intranuclear inclusion bodies present in superficial cells. An adenovirus was isolated in both chicken and goose embryo liver cells.

Early region 4 sequence and biological comparison of two isolates of mouse adenovirus type 1

The DNA sequence of 88-100 map units of mouse adenovirus type 1 (MAV-1) was determined. One translational open reading frame showed 48% sequence similarity to a human adenovirus type 2 early region 4 protein. Based on the protein similarity, genome location, and transcriptional polarity, we concluded that this region of MAV-1 corresponds to early region 4. A 241-bp sequence consisting of 10 imperfect direct repeats with sequence similarity to minisatellite DNA was found in this region. Two virus isolates with different passage histories were examined and were found to have a sequence polymorphism within this region. The two viruses were compared for growth in cell culture and mice and small quantitative differences were observed only in vivo.

Observations of experimentally induced quail bronchitis

Quail bronchitis was experimentally reproduced in captive-reared bobwhite quails (Colinus virginianus). Quails were inoculated with 10(6) mean tissue culture infective doses of quail bronchitis virus at 1,3,6, or 9 weeks of age by the intratracheal, intraperitoneal, or subcutaneous route. Clinical signs were minimal, but occasionally birds were ruffled, exhibited open-mouthed breathing, and developed "snicks." Mortality rates of quails inoculated at 1 or 3 weeks ranged from 7% to 87%. Quails inoculated at 6 or 9 weeks of age had mortality rates from 0% to 20%. Mean body weights of survivors that had been inoculated at 3 or 6 weeks were significantly less than those of controls (P less than 0.05). No significant differences in body weight were detected between quails inoculated at 1 or 9 weeks and their uninoculated controls. Antibodies to group I adenovirus were detected by agar gel precipitation in 87.5% of birds that survived infection.

Effect of avian adeno-associated virus on pathogenicity of Tipton virus in chicks

The avian adeno-associated virus (A-AV) reduced the pathogenicity of an adenovirus infection in vivo. Groups of chicks were infected with Tipton virus alone or in combination with high or low doses of A-AV. In both trials, the associated virus delayed and reduced chick mortality. This effect was dose-dependent and significant at the higher dose level.

Epidemic adenovirus inclusions body hepatitis of the chicken in Australia

The occurrence of inclusion body hepatitis (IBH) on 11 properties in Australia is described. The 6 Victorian cases occurred between 1967 and 1973 and were identified as incidental findings accompanying other diseases or occurred as ill-defined, minor economic disease episodes. In well-managed flocks the extra mortality attributable to IBH was as low as 1.8% which represented a 50% increase in total mortality. The 1973 epidemic in New South Wales on 5 related farms resulted in flock mortality of 8.4% to 32.3% and an average mortality of 19.5% of 814,000 birds. For uninfected flocks of 307,000 birds the average mortality was 8.5%. Higher mortality in male flocks was statistically highly significant as was lowered efficiency of feed conversion. Growth rate in both sexes was depressed by about 0.15 kg in 70 days and heavy downgrading at processing occurred. Secondary infections were important. The cardinal features of IBH were fatal necrotising hepatitis with Cowdry type-A intranuclear inclusion body formation; secondary bacterial infections were also important causes of loss.

Virological studies of sudden, unexplained infant deaths in Glasgow 1967-70

Virus isolation tests on 72 sudden unexplained infant deaths and 34 cases of explained death showed that 42 and 29% respectively had virus infections. A wide range of viruses was encountered, mainly enteroviruses and adenoviruses, mostly from bowel specimens. The findings did not suggest that overwhelming virus infection was a common feature of sudden death in infancy.