Necrotizing tracheobronchitis causing airway obstruction complicated by pandemic 2009 H1N1 influenza: A case report.

RATIONALE: Influenza is an infection caused by the influenza virus, and its symptoms are mostly mild and self-limiting. However, influenza can cause severe or fatal complications in high-risk patients. Although tracheobronchitis is one of the common complications of influenza, necrotizing tracheobronchitis is very rare. Herein, we describe a case of necrotizing tracheobronchitis causing airway obstruction complicated by pandemic 2009 H1N1 influenza. PATIENT CONCERNS: A 60-year-old man presented with fever and dyspnea. On arrival at the emergency room (ER), the patient received oxygen 4 L/minute via a nasal prolong owing to mild hypoxemia. And invasive mechanical ventilation was needed 5 hours after arrival at the ER due to progressive hypoxemia. DIAGNOSES: Fiberoptic bronchoscopy was performed owing to bloody secretion in the endotracheal tube and revealed diffuse tracheobronchitis with necrotic and hemorrhagic materials obstructing the trachea and bronchus. The pandemic 2009 H1N1 influenza virus was detected from the bronchial washing sample; no other microorganism was detected. INTERVENTION: He received peramivir plus oseltamivir and broad-spectrum antibiotics. OUTCOMES: The bloody secretion continued. He developed cardiac arrest due to airway obstruction on the 6th day of admission. After cardiac arrest, his condition progressed to multi-organ failure, and the patient died on the 10th day of admission. LESSONS: We suggest that necrotizing tracheobronchitis be considered in patients with influenza who present with unexplained hypoxemia.

Prevalence and clinical implications of low-risk human papillomavirus among patients with recurrent respiratory papillomatosis in Rio de Janeiro, Brazil.

OBJECTIVE: The aim of this study was to investigate the presence of human papillomavirus (HPV) in biopsy specimens from juvenile and adult patients with histopathological diagnosis of recurrent respiratory papillomatosis (RRP) treated in two public hospitals in Rio de Janeiro, Brazil. METHODS: We performed the detection and genotyping of HPV by PCR technique for the types 6, 11, 16, and 18 in biopsy specimens from 41 RRP patients. RESULTS: The juvenile onset RRP (JoRRP) corresponded to 61% and the adult onset RRP (AoRRP) corresponded to 39% of the study group. Prevalence of males was observed in both the adult (81.3%) and the juvenile (56%) groups. Lesions in the larynx were more frequent in the glottis (46%). Genotyping analysis only revealed patients with HPV-6 (34.1%), HPV-11(17.1%), and co-infection HPV-6 and -11 (48.8%). RRP severity was significantly associated with the JoRRP (p<0.001), with extralaryngeal disease and more surgeries. However, no significant association between RRP severity and HPV types was found. One co-infected patient in the JoRRP died due to the evolution of the disease with lung involvement. CONCLUSION: These results show the strong association of HPV-6 and/or HPV-11 types with RRP and could complement the diagnosis, prognosis, and therapies for these patients. In addition, the HPV vaccination should be encouraged to prevent the disease.

Avian coronavirus isolated from a pigeon sample induced clinical disease, tracheal ciliostasis, and a high humoral response in day-old chicks.

The detection of avian coronaviruses (AvCoV) in wild birds and the emergence of new AvCoV have increased in the past few years. In the present study, the pathogenicity of three AvCoV isolates was investigated in day-old chicks. One AvCoV isolated from a pigeon, which clustered with the Massachusetts vaccine serotype, and two AvCoV isolated from chickens, which grouped with a Brazilian genotype lineage, were used. Clinical signs, gross lesions, histopathological changes, ciliary activity, viral RNA detection, and serology were evaluated during 42 days post infection. All AvCoV isolates induced clinical signs, gross lesions in the trachea, moderate histopathological changes in the respiratory tract, and mild changes in other tissues. AvCoV isolated from the pigeon sample caused complete tracheal ciliostasis over a longer time span. Specific viral RNA was detected in all tissues, but the highest RNA loads were detected in the digestive tract (cloacal swabs and ileum). The highest antibody levels were also detected in the group infected with an isolate from the pigeon. These results confirm the pathogenicity of Brazilian variants, which can cause disease and induce gross lesions and histopathological changes in chickens. Our results suggest that non-Galliformes birds can also play a role in the ecology of AvCoV.

Tracheal papillomatosis: what do we know so far?

Tracheal papillomatosis (TP) is a benign condition characterized by papillomatous growth of the bronchial epithelium that involves the trachea. This abnormal growth is a result of infection with human papilloma virus (HPV). Two subtypes of HPV were found in most cases of TP, HPV-6 and HPV-11. TP, presents in two forms, the juvenile onset (JO) or adult onset (AO). The clinical presentation is typically nonspecific and it ranges from mild symptoms like cough to life-threatening conditions like upper airway obstruction. Treatment depends on the location of the papillomas and age of the patient and the plan of therapy is usually made on an individual basis. Treatment can range from observation with symptomatic control to specific medical therapy and multiple surgeries in case of recurrence or progressively worsening disease. The recent invention of HPV vaccine is expected to be the first step in eradicating respiratory papillomatosis.

Roles of vaccinia virus genes E3L and K3L and host genes PKR and RNase L during intratracheal infection of C57BL/6 mice.

The importance of the 2'-5' oligoadenylate synthetase (OAS)/RNase L and double-stranded RNA (dsRNA)-dependent protein kinase (PKR) pathways in host interferon induction resulting from virus infection in response to dsRNA has been well documented. In poxvirus infections, the interactions between the vaccinia virus (VV) genes E3L and K3L, which target RNase L and PKR, respectively, serve to prevent the induction of the dsRNA-dependent induced interferon response in cell culture. To determine the importance of these host genes in controlling VV infections, mouse single-gene knockouts of RNase L and PKR and double-knockout mice were studied following intratracheal infection with VV, VVΔK3L, or VVΔE3L. VV caused lethal disease in all mouse strains. The single-knockout animals were more susceptible than wild-type animals, while the RNase L(-/-) PKR(-/-) mice were the most susceptible. VVΔE3L infections of wild-type mice were asymptomatic, demonstrating that E3L plays a critical role in controlling the host immune response. RNase L(-/-) mice showed no disease, whereas 20% of the PKR(-/-) mice succumbed at a dose of 10(8) PFU. Lethal disease was routinely observed in RNase L(-/-) PKR(-/-) mice inoculated with 10(8) PFU of VVΔE3L, with a distinct pathology. VVΔK3L infections exhibited no differences in virulence among any of the mouse constructs, suggesting that PKR is not the exclusive target of K3L. Surprisingly, VVΔK3L did not disseminate to other tissues from the lung. Hence, the cause of death in this model is respiratory disease. These results also suggest that an unanticipated role of the K3L gene is to facilitate virus dissemination.

Survey of Florida green turtles for exposure to a disease-associated herpesvirus.

A recently developed enzyme-linked immunosorbent assay (ELISA) was used to assess exposure of Florida wild green turtles Chelonia mydas to LETV, the herpesvirus associated with lung-eye-trachea disease (LETD). Plasma samples from 329 wild juvenile green turtles netted in the Indian River lagoon, along the Sebastian reef, or in the Trident basin (Indian River and Brevard Counties, Florida) were tested by ELISA for the presence of antibodies to LETV. Plasma samples from 180 wild juvenile green turtles were tested from these study sites to compare the prevalence of anti-LETV antibodies. While some plasma samples from each site contained anti-LETV antibodies (confirmed by Western blot analysis), plasma samples collected from the Indian River lagoon had statistically higher optical density values measured in the ELISA. No statistical differences were observed when these same plasma samples were analyzed for changes in the level of anti-LETV antibodies over 3 years (1997, 1998, and 1999). To explore the relationship between anti-LETV antibodies and fibropapillomatosis (FP), plasma from 133 green turtles scored for fibropapilloma tumor severity were tested by ELISA. There was no correlation between tumor severity and the presence of antibodies against LETV. Additional plasma samples collected from 16 tagged green turtles captured and sampled more than once (recaptures) were also tested to monitor antibody levels to LETV relative to the FP status of individual turtles over time. Again there was no clear relationship between FP tumor status and the presence of antibodies to LETV. Finally, ELISA tests on plasma from 13 nesting female turtles (9 green and 4 loggerhead) revealed high levels of anti-LETV antibodies in 11 individuals, including 2 loggerhead turtles. These results provide strong evidence that wild Florida green turtle populations at these 3 study sites are exposed to LETV or a closely related virus and that loggerhead turtles may be exposed as well. Based on a cutoff optical density value of 0.310, 71 out of the 329 wild Florida green turtles tested were seropositive for LETV antibodies (seroprevalence = 21.6%). In addition, no relationship between FP tumor severity or status and the presence of anti-LETV antibodies was found, further supporting the hypothesis that LETV and the FP-associated herpesvirus (FPHV) are separate infections of marine turtles.

Persistent infectivity of a disease-associated herpesvirus in green turtles after exposure to seawater.

Herpesviruses are associated with several diseases of marine turtles including lung-eye-trachea disease (LETD) and gray patch disease (GPD) of green turtles (Chelonia mydas) and fibropapillomatosis (FP) of green, loggerhead (Caretta caretta), and olive ridley turtles (Lepidochelys olivacea). The stability of chelonian herpesviruses in the marine environment, which may influence transmission, has not been previously studied. In these experiments, LETD-associated herpesvirus (LETV) was used as a model chelonian herpesvirus to test viral infectivity after exposure to seawater. The LETV virus preparations grown in terrapene heart (TH-1) cells were dialyzed for 24 to 120 hr against aerated artificial or natural seawater or Hank's balanced salt solution (HBBS). Fresh TH-1 cells were inoculated with dialyzed LETV, and on day 10 post-infection cells were scored for cytopathic effect. Virus samples dialyzed up to 120 hr were positive for the herpesvirus DNA polymerase gene by polymerase chain reaction. Electron microscopy revealed intact LETV nucleocapsids after exposure of LETV to artificial seawater or HBSS for 24 hr at 23 C. LETV preparations remained infectious as long as 120 hr in natural and artificial seawater at 23 C. Similar results were obtained with a second culturable chelonian herpesvirus, HV2245. LETV infectivity could not be detected after 48 hr exposure to artificial seawater at 30 C. Since LETV and HV2245 remain infectious for extended periods of time in the marine environment, it is possible that FP-associated and GPD-associated herpesviruses also may be stable. These findings are significant both for researchers studying the epidemiological association of herpesviruses with diseases of marine turtles and for individuals who handle turtles in marine turtle conservation efforts.

In situ hybridization for the detection of infectious laryngotracheitis virus in sections of trachea from experimentally infected chickens.

An in situ hybridization procedure for the detection of infectious laryngotracheitis virus (ILTV) in experimentally infected chickens is described. Formalin-fixed, paraffin-embedded sections of trachea, taken from chickens on days 3-10 post-inoculation (p.i.) with ILTV were hybridized with a mixture of 2 biotinylated, polymerase chain reaction-generated DNA fragments. The fragments correspond to sequences of the ILTV glycoprotein C and thymidine Kinase genes. In situ hybridization was seen in 7 out of 7 chickens examined on day 3 p.i., 2 out of 2 examined on day 4 p.i. and 3 out of 3 examined on day 5 p.i. No hybridization was observed in 3 out of 3 chickens examined on day 10 p.i. ILTV nucleic acid was detected in nuclei of degenerated tracheal epithelial cells and in intranuclear inclusion bodies of syncytia.