The burden of parainfluenza virus infection in patients with hematological malignancy and hematopoietic stem cell transplant (HSCT) recipients in the absence of active immunization and approved therapy: The role of infection control

Background. Community respiratory viruses, mainly RSV and influenza, are significant causes of morbidity and mortality in patients with leukemia and HSCT recipients. The data on impact of PIV infections in these patients is lacking. Methods. We reviewed the records of patients with leukemia and HSCT recipients who developed PIV infection from Oct'02–Nov'07 to determine the outcome of such infections. Results. We identified 200 patients with PIV infections including 80(40%) patients with leukemia and 120 (60%) recipients of HSCT. Median age was 55 y (17-84 y). As compared to HSCT recipients, patients with leukemia had higher APACHE II score (14 vs. 10, p<0.0001); were more likely to have ANC<500 (48% vs. 10%, p<0.0001) and ALC<200 (45% vs. 23.5%, p=0.02). PIV type III was the commonest isolate (172/200, 86%). Most patients 141/200 (70%) had upper respiratory infection (URI), and 59/200 (30%) had pneumonia at presentation. Patients in leukemia group were more likely to require hospitalization due to PIV infection (77% vs. 36% p=0.0001) and were more likely to progress to pneumonia (61% vs. 39%, p=0.002). Fifty five patients received aerosolized ribavirin and/or IVIG. There were no significant differences in the duration of symptoms, length of hospitalization, progression to pneumonia or mortality between the treated verses untreated group. The clinical outcome was unknown in 13 (6%) patients. Complete resolution of symptoms was noted in 91% (171/187) patients and 9% (16/187) patients died. Mortality rate was 17% (16/95) among patients who had PIV pneumonia, with no significant difference between leukemia and HSCT group (16% vs. 17%). The cause of death was acute respiratory failure and/or multi-organ failure in (13, 81%) patients. Conclusions. Patients with leukemia and HSCT could be at high risk for serious PIV infections including PIV pneumonia. Treatment with aerosolized ribavirin and/or IVIG may not have significant effect on the outcome of PIV infection.^

Studies of biological rhythms in responses to influenza infection and vaccination

Three studies examined seasonal or circadian variations in selected responses to influenza infection or vaccination. The first, a seroepidemiologic study, evaluated temporal patterns of antibody titers to influenza A/Texas. Human umbilical cord bloods were sampled over a two-year period when the virus was not present in the community. No endogenous seasonal pattern was detected. The second study included three experiments on circadian rhythms in mice. Neither susceptibility nor protection from inactivated or attenuated vaccine varied significantly according to time of administration. A slight effect, however, was suggested with inactivated vaccine. Three human vaccine trials comprised the third study. Outcome variables included rise in antibody titer, final antibody titer, incidence of adverse reactions, and protection from community infection. Patterns in antibody response and protection variables were inconsistent, and generally not clinically significant. Local reactions to inactivated vaccine were more frequent if injections were received in the afternoon as compared to morning. This was true to adults that had been previously vaccinated. ^

SERIOUS MORBIDITY DUE TO ACUTE RESPIRATORY DISEASE ASSOCIATED WITH EPIDEMIC INFLUENZA

Current measures of the health impact of epidemic influenza are focused on analyses of death certificate data which may underestimate the true health effect. Previous investigations of influenza-related morbidity have either lacked virologic confirmation of influenza activity in the community or were not population-based. Community virologic surveillance in Houston has demonstrated that influenza viruses have produced epidemics each year since 1974. This study examined the relation of hospitalized for Acute Respiratory Disease (ARD) to the occurrence of influenza epidemics. Considering only Harris County residents, a total of 13,297 ARD hospital discharge records from hospitals representing 48.4% of Harris County hospital beds were compiled for the period July 1978 through June 1981. Variables collected from each discharge included: age, sex, race, dates of admission and discharge, length of stay, discharge disposition and a maximum of five diagnoses. This three year period included epidemics caused by Influenza A/Brazil (H1N1), Influenza B/Singapore, Influenza A/England (H1N1) and Influenza A/Bangkok (H3N2).^ Correlations of both ARD and pneumonia or influenza hospitalizations with indices of community morbidity (specifically, the weekly frequency of virologically-confirmed influenza virus infections) are consistently strong and suggest that hospitalization data reflect the pattern of influenza activity derived from virologic surveillance.^ While 65 percent of the epidemic period hospital deaths occurred in patients who were 65 years of age or older, fewer than 25 percent of epidemic period ARD hospitalizations occurred in persons of that age group. Over 97 percent of epidemic period hospital deaths were accompanied by a chronic underlying illness, however, 45 percent of ARD hospitalizations during epidemics had no mention of underlying illness. Over 2500 persons, approximately 35 percent of all persons hospitalized during the three epidemics, would have been excluded in an analysis for high risk candidates for influenza prophylaxis.^ These results suggest that examination of hospitalizations for ARD may better define the population-at-risk for serious morbidity associated with epidemic influenza. ^

The development of poultry farms risk assessment tool for avian influenza in Imo State, Nigeria

Background: Nigeria was one of the 13 countries where avian influenza outbreak in poultry farms was reported during the 2006 avian influenza pandemic threat and was also the first country in Africa to report the presence of H5N1influenza among its poultry population. There are multiple hypotheses on how the avian influenza outbreak of 2006 was introduced to Nigeria, but the consensus is that once introduced, poultry farms and their workers were responsible for 70% of the spread of avian influenza virus to other poultry farms and the population. ^ The spread of avian influenza has been attributed to lack of compliance by poultry farms and their workers with poultry farm biosecurity measures. When poultry farms fail to adhere to biosecurity measures and there is an outbreak of infectious diseases like in 2006, epidemiological investigations usually assess poultry farm biosecurity—often with the aid of a questionnaire. Despite the importance of questionnaires in determining farm compliance with biosecurity measures, there have been few efforts to determine the validity of questionnaires designed to assess poultry farms risk factors. Hence, this study developed and validated a tool (questionnaire) that can be used for poultry farm risk stratification in Imo State, Nigeria. ^ Methods: Risk domains were generated using literature and recommendations from agricultural organizations and the Nigeria government for poultry farms. The risk domains were then used to develop a questionnaire. Both the risk domain and questionnaire were verified and modified by a group of five experts with a research interest in Nigeria's poultry industry and/or avian influenza prevention. Once a consensus was reached by the experts, the questionnaire was distributed to 30 selected poultry farms in Imo State, Nigeria that participated in this study. Survey responses were received for all the 30 poultry farms that were selected. The same poultry farms were visited one week after they completed the questionnaires for on-site observation. Agreement among survey and observation results were analyzed using a kappa test and rated as poor, fair, moderate, substantial, or nearly perfect; and internal consistency of the survey was also computed. ^ Result: Out of the 43 items on the questionnaire, 32 items were validated by this study. The agreement between the survey result and onsite observation was analyzed using kappa test and ranged from poor to nearly perfect. Most poultry farms had their best agreements in the contact section of the survey. The least agreement was noted in the farm management section of the survey. Thirty-two questions on the survey had a coefficient alpha > 0.70, which is a robust internal consistency for the survey. ^ Conclusion: This study developed 14 risk domains for poultry farms in Nigeria and validated 32 items from the original questionnaire that contained 43 items. The validated items can be used to determine the risk of introduction and spread of avian influenza virus in poultry farms in Imo State, Nigeria. After further validations in other states, regions and poultry farm sectors in Nigeria; this risk assessment tool can then be used to determine the risk profile of poultry farms across Nigeria.^