Respiratory syncytial virus acute respiratory infections in ≥ 65-year-old adults in long-term care facilities in the Czech Republic.

OBJECTIVES: Due to immunosenescence and presence of comorbidities, respiratory syncytial virus (RSV) disease burden is a major health concern in older adults, which is expected to increase with the life expectancy rise. Data on RSV burden are scarce in older adults residing in long-term care facilities, a vulnerable population living in crowded settings. Therefore, two independent prospective studies were conducted during the 2003-2004 and 2004-2005 RSV seasons to assess RSV acute respiratory illnesses (ARIs) and lower respiratory tract infections (LRTIs) in ≥ 65-year-old adults residing in long-term care facilities in the Czech Republic. METHODS: RSV ARI episodes were confirmed by polymerase chain reaction in nasal swabs collected within 3 days of symptoms onset. The mortality and morbidity of RSV-confirmed ARIs, as well as the risk factors associated with RSV-confirmed ARIs were evaluated. RESULTS: Among 1,251 participants in the 2003-2004 season (ARI surveillance between October and March), there were no RSV-positive cases in 255 ARI and 105 LRTI episodes. Among 1,280 participants in the 2004-2005 season (ARI surveillance between October and April), there were 39 and 26 RSV-positive cases in 335 ARI and 217 LRTI episodes, respectively, and RSV-positive ARI and LRTI episode incidence rates were 45.82 and 30.40 per 1,000 person-years. Among 290 RSV-negative and 39 RSV-positive ARI cases in the 2004-2005 season, 15 and 4 hospitalizations, 188 and 26 LRTIs, and 11 and 3 deaths were reported. Risk factors associated with RSV-positive ARI were female gender (odds ratio: 4.98), chronic heart failure class II (odds ratio: 2.31) and diabetes requiring insulin treatment (odds ratio: 9.82). CONCLUSIONS: These studies showed that RSV was an important cause of ARI in older adults living in long-term care facilities in the 2004-2005 season, with fluctuating yearly incidences.

Atypical scrapie/Nor98 in a sheep from New Zealand.

In a consignment of sheep brains from New Zealand, to be used in Europe as negative control material in scrapie rapid screening test evaluations, brain samples from 1 sheep (no. 1512) gave the following initially confusing results in various screening tests: the brainstem repeatedly produced negative results in 2 very similar screening kits (enzyme-linked immunosorbent assay [ELISA]-1, ELISA-2), a macerate made from brainstem and cerebellum returned a clearly positive result in ELISA-2, and the macerate and a brainstem sample gave negative results in a third screening test (ELISA-3). In subsequent testing, cerebellum tissue alone tested strongly positive in ELISA-1 and produced a banding pattern very similar to atypical scrapie/Nor98 in a confirmatory Western blot (WB). The macerate showed weak staining in the confirmatory WB but presented a staining pattern identical to atypical scrapie/Nor98 in the scrapie-associated fibril WB. The latter test confirmed conclusively the first case of atypical scrapie/Nor98 in a sheep from New Zealand. Other parts of the brain either tested negative or very weak positive in ELISA-2 and in WBs, or tested with negative results by histopathology and immunohistochemistry. It appears that sheep no. 1512 is a case of atypical scrapie/Nor98 in which the abnormal prion protein was detected mainly in the cerebellum. This case emphasizes the need to retain brainstem, and cerebral and cerebellar tissues, as frozen and fixed materials, for conclusive confirmatory testing. Furthermore, consideration should be given to which screening method to use.

A four year longitudinal sero-epidemiological study of bovine herpesvirus type-1 (BHV-1) in adult cattle in 107 unvaccinated herds in south west England.

BACKGROUND: Bovine herpesvirus type-1 (BHV-1) is an important pathogen of cattle that presents with a variety of clinical signs, including the upper respiratory tract infection infectious bovine rhinotracheitis (IBR). A seroepidemiological study of BHV-1 antibodies was conducted in England from 2002 - 2004: 29,782 blood samples were taken from 15,736 cattle from 114 herds which were visited on up to three occasions. Antibody concentration was measured using a commercial ELISA. Farm management information was collected using an interview questionnaire, and herd size and cattle movements were obtained from the cattle tuberculosis testing database and the British Cattle Movement Service. Hierarchical statistical models were used to investigate associations between cattle and herd variables and the continuous outcome percentage positive (PP) values from the ELISA test in unvaccinated herds. RESULTS: There were 7 vaccinated herds, all with at least one seropositive bovine. In unvaccinated herds 83.2% had at least one BHV-1 seropositive bovine, and the mean cattle and herd BHV-1 seroprevalence were 42.5% and 43.1% respectively. There were positive associations between PP value, age, herd size, presence of dairy cattle. Adult cattle in herds with grower cattle had lower PP values than those in herds without grower cattle. Purchased cattle had significantly lower PP values than homebred cattle, whereas cattle in herds that were totally restocked after the foot-and-mouth epidemic in 2001 had significantly higher PP values than those in continuously stocked herds. Samples taken in spring and summer had significantly lower PP values than those taken in winter, whereas those taken in autumn had significantly higher PP values than those taken in winter. The risks estimated from a logistic regression model with a binary outcome (seropositive yes/no) were similar. CONCLUSION: The prevalence of BHV-1 seropositivity in cattle and herds has increased since the 1970s. Although the study population prevalence of BHV-1 was temporally stable during study period, the associations between serological status and cattle age, herd size, herd type, presence of young stock and restocked versus continuously stocked herds indicate that there is heterogeneity between herds and so potential for further spread of BHV-1 within and between herds.

Evaluation of a risk score to predict future Clostridium difficile disease using UK primary care and hospital data in Clinical Practice Research Datalink.

We evaluated the applicability of a Clostridium difficile infection (CDI) risk index developed for patients at hospital discharge to identify persons at high-risk of CDI in a primary care population. This retrospective observational study used data from the UK Clinical Practice Research Datalink, linked with Hospital Episodes Statistics. The risk index was based on the following patient characteristics: age, previous hospitalizations, days in hospital, and prior antibiotics use. Individual risk scores were calculated by summing points assigned to pre-defined categories for each characteristic. We assessed the association of risk factors with CDI by multivariate logistic regression. The estimated CDI incidence rate was 4/10,000 and 2/10,000 person-years in 2008 and 2012, respectively. On an index with a maximal risk of 19, a cut-off for high risk of ≥7 had sensitivity, specificity and positive predictive values of 80%, 87% and 12%, respectively. A high-risk person had a ~ 35% higher risk of CDI than a low-risk person. Multivariate risk factor analysis indicated a need to reconsider the relative risk scores. The CDI risk index can be applied to the UK primary care population and help identify study populations for vaccine development studies. Reassessing the relative weights assigned to risk factors could improve the index performance in this setting.

A four year longitudinal sero-epidemiology study of Neospora caninum in adult cattle from 114 cattle herds in south west England: associations with age, herd and dam-offspring pairs.

BACKGROUND: Neosporosis caused by the protozoan parasite Neospora caninum, is an economically important cause of abortion, stillbirth, low milk yield, reduced weight gain and premature culling in cattle. Consequently, a seroepidemiological study of N. caninum antibodies was conducted in England with 29,782 samples of blood taken from 15,736 cattle from 114 herds visited on three occasions at yearly intervals. Herds were categorised into lower (< 10%) and higher (> or = 10%) median herd seroprevalence. Hierarchical models were run to investigate associations between the sample to positive (S/P) ratio and herd and cattle factors. RESULTS: Ninety-four percent of herds had at least one seropositive cow; 12.9% of adult cattle had at least one seropositive test. Approximately 90% of herds were seropositive at all visits; 9 herds (8%) changed serological status between visits. The median N. caninum seroprevalence in positive herds was 10% (range 0.4% to 58.8%). There was a positive association between the serostatus of offspring and dams that were ever seropositive. In the hierarchical model of low seroprevalence herds there was no significant association between S/P ratio and cattle age. There was a significantly lower S/P ratio in cattle in herds that were totally restocked after the foot-and-mouth epidemic of 2001 compared with those from continuously stocked herds and cattle purchased into these herds had a higher S/P ratio than homebred cattle. In the model of high seroprevalence herds the S/P ratio increased with cattle age, but was not associated with restocking or cattle origin. CONCLUSION: There were no strong temporal changes in herd seroprevalence of N. caninum but 90% of herds had some seropositive cattle over this time period. Vertical transmission from seropositive dams appeared to occur in all herds. In herds with a high seroprevalence the increasing S/P ratio in 2-4 year old cattle is suggestive of exposure to N. caninum: horizontal transmission between adult cattle, infection from a local source or recrudescence and abortions. Between-herd movements of infected cattle enhance the spread of N. caninum, particularly into low seroprevalence herds. Some restocked herds had little exposure to N. caninum, while in others infection had spread in the time since restocking.

Seroprevalence and epidemiological characteristics of Mycobacterium avium subsp. paratuberculosis on 114 cattle farms in south west England.

Between December 2002 and April 2006, 114 cattle farms in the south west of England were visited at least once, with 100 farms visited three times. A total of 29,782 serum samples were collected from 15,736 individually identified cattle. The sera were tested for the presence of antibodies against Mycobacterium avium subsp. paratuberculosis (MAP) using an indirect enzyme-linked immunosorbent assay (ELISA). The mean seroprevalence in herds sampled three times was 7.1%; 10.1% of cattle had at least one positive result. There were 78%, 75% and 75% dairy herds with at least one positive bovine at the first, second and third routine visits, respectively. In comparison, 44%, 42% and 46% suckler herds had at least one positive bovine for the first, second and third routine visits, respectively. In most herds (>90%), within herd seroprevalence of MAP remained stable over time. Markov chain Monte Carlo (MCMC) simulation methods were used to re-estimate the test sensitivity and specificity. The sensitivity results were 33.3% (95% CI, 28.8-37.8%), 34.5% (95% CI, 30.3-38.8%) and 34.8% (95% CI, 30.8-38.9%) for the first, second and third routine visits and the specificity results were 99.7% (95% CI, 99.3-99.9%), 99.8% (95% CI, 99.4-99.9%) and 99.7% (95% CI, 99.3-99.9%) for the first, second and third routine visits, respectively. The expected true prevalence was also estimated, 11 (21.1%) suckler herds and 1 (2.1%) dairy herd were predicted to be truly free from infection during the study period. The seroprevalence of antibodies against MAP increased with cattle age. There was a significantly higher seroprevalence of MAP in dairy breeds of cattle compared with suckler breeds of cattle. This was more pronounced in Channel Island breeds. Smaller dairy herds (<100 cattle) had a relatively lower seroprevalence of MAP than dairy herds with >/=100 cattle. In 8 (42%) of the 19 herds with > or =100 cattle born into the same herd, seropositive cattle were clustered by birth month whilst in the remaining herds clustering was not apparent. Daughters were significantly more likely to be MAP seropositive when born to a seropositive dam.