Human immunodeficiency virus testing uptake and risk behaviours in Spain

BACKGROUND

The purpose of this study was to estimate the prevalence of human immunodeficiency (HIV) testing in the general population; to analyse factors related to voluntary testing; and to describe the main reasons for testing, the kinds of health services where testing takes place and the relations between self-risk perception and HIV testing.

METHODS

A probability sample survey of health and sexual behaviour in men and women aged 18-49 years and resident in Spain in 2003 (n = 10 980) was used. A combination of face-to-face and computer-assisted self-interview was used, and bivariate and multivariate logistic regression analyses were performed.

RESULTS

Some 39.4% (40.2% in men and 38.5% in women) had ever been tested, blood donation being the main reason for men and pregnancy for women. In the multivariate analysis, HIV testing was associated with foreign nationality, high educational level, having injected drugs and having a large number of sexual partners. In men, it was also associated with age 30-39 years, having had sex with other men and having paid for sex. About 29.3% of men and 32.8% of women had their last voluntary HIV test in primary healthcare centres, whereas only 3.4% of men and 3.6% of women had last been tested in sexually transmitted infection/HIV diagnostic centres. About 20.2% of men and 5.5% of women with risk behaviours had never been tested.

CONCLUSION

The proportion of men with risk behaviours who have never had an HIV test is unacceptably high in Spain. Scaling up access to HIV testing in this population group remains a challenge for health policies and research.

[Heptavalent-pneumococcal conjugate vaccine (Prevenar). Differences in effectiveness between populations]

This article reviews the publications on the effectiveness of heptavalent-pneumococcal conjugate vaccine (PCV7) in the prevention of invasive pneumococcal disease (IPD) in children under five years of age. It also analyses the characteristics of the vaccine and its impact on the epidemiology of IPD in different places. Before the introduction of PCV7, the percentage of cases of IPD due to vaccine serogroups oscillated between 89% in the United States and 43% in Asia. In Spain it was 68%. Active laboratory-based surveillance shows that the introduction of PCV7 has had a highly variable impact on the incidence of IPD, with falls oscillating between 91% in the United States and 12% in Navarre, Spain. The global effectiveness of VNC7v in published studies varies between 31% and 89%, chiefly depending on the patterns of pneumococcal serotypes in each place. Numerous studies show a variable replacement capacity of the pneumococci, which means the effect of the vaccine can be reduced, as non-vaccine serotypes occupy the space left by the vaccine ones. A study in Navarre has found a risk of IPD due to non-vaccine serotypes that is 6 times higher in vaccinated children than in unvaccinated ones. In places where less than 70% of the serotypes that cause IPD are represented in the VNC7v, the effectiveness of its introduction in the vaccination will probably be slight and the routine vaccination schedule serotypes fast. In these cases, VNC7v could be reserved for children with IPD risk factors.

Cell-free propagation of prion strains

Prions are the infectious agents responsible for prion diseases, which appear to be composed exclusively by the misfolded prion protein (PrP(Sc)). Disease is transmitted by the autocatalytic propagation of PrP(Sc) misfolding at the expense of the normal prion protein. The biggest challenge of the prion hypothesis has been to explain the molecular mechanism by which prions can exist as different strains, producing diseases with distinguishable characteristics. Here, we show that PrP(Sc) generated in vitro by protein misfolding cyclic amplification from five different mouse prion strains maintains the strain-specific properties. Inoculation of wild-type mice with in vitro-generated PrP(Sc) caused a disease with indistinguishable incubation times as well as neuropathological and biochemical characteristics as the parental strains. Biochemical features were also maintained upon replication of four human prion strains. These results provide additional support for the prion hypothesis and indicate that strain characteristics can be faithfully propagated in the absence of living cells, suggesting that strain variation is dependent on PrP(Sc) properties.

Accelerated high fidelity prion amplification within and across prion species barriers

Experimental obstacles have impeded our ability to study prion transmission within and, more particularly, between species. Here, we used cervid prion protein expressed in brain extracts of transgenic mice, referred to as Tg(CerPrP), as a substrate for in vitro generation of chronic wasting disease (CWD) prions by protein misfolding cyclic amplification (PMCA). Characterization of this infectivity in Tg(CerPrP) mice demonstrated that serial PMCA resulted in the high fidelity amplification of CWD prions with apparently unaltered properties. Using similar methods to amplify mouse RML prions and characterize the resulting novel cervid prions, we show that serial PMCA abrogated a transmission barrier that required several hundred days of adaptation and subsequent stabilization in Tg(CerPrP) mice. While both approaches produced cervid prions with characteristics distinct from CWD, the subtly different properties of the resulting individual prion isolates indicated that adaptation of mouse RML prions generated multiple strains following inter-species transmission. Our studies demonstrate that combined transgenic mouse and PMCA approaches not only expedite intra- and inter-species prion transmission, but also provide a facile means of generating and characterizing novel prion strains.

[Epidemiology of notifiable diseases in Navarre, 2006]

Epidemiological vigilance in Navarre (601,874 inhabitants) in 2006 included 34 diseases whose notification is compulsory and epidemic outbreaks. Notification is carried out on a weekly basis by the doctors from paediatrics, primary care and specialised care facing any suspicion of these processes, and is completed with microbiological diagnoses. In 2006 the incidence of influenza reached 16.8 cases per 1,000 inhabitants (Epidemic Index, EI: 0.46), showing a late seasonal peak (March) of low dimensions. The incidence of respiratory tuberculosis was 11.3 cases per 100,000 inhabitants, and that of non-respiratory tuberculosis was 2.3; both at similar levels to recent years. Seven cases of tuberculosis occurred in three aggregates amongst cohabitants, and another 7 in non-cohabiting persons resident in the same municipality. Six percent of the cases were coinfected with HIV, and 37% occurred in immigrants. The incidence of meningococcal disease rose to 19 cases (3.2 cases per 100,000 inhabitants; EI 1.46), all of them sporadic. Neisseria meningitidis serogroup B was isolated in 16 cases. There was one case of serogroup C, in a child who had received 3 doses of combined vaccine. In two cases (11%) death occurred. The incidence of legionnaire's disease rose to 28 cases per 100,000 inhabitants (EI:4.88), due to a community outbreak that affected 146 people. Excluding this outbreak, incidence was similar to previous years (3.3 per 100,000 inhabitants). In August an outbreak of parotitis began, and 911 cases had been counted until the end of 2006; and it has continued during 2007. Eleven cases of malaria were registered, all imported. Notifications of toxic food infections has continued to fall (IE:0.48).

A large Legionnaires' disease outbreak in Pamplona, Spain: early detection, rapid control and no case fatality

An outbreak of Legionnaire's disease was detected in Pamplona, Spain, on 1 June 2006. Patients with pneumonia were tested to detect Legionella pneumophila antigen in urine (Binax Now; Binax Inc., Scarborough, ME, USA), and all 146 confirmed cases were interviewed. The outbreak was related to district 2 (22 012 inhabitants), where 45% of the cases lived and 50% had visited; 5% lived in neighbouring districts. The highest incidence was found in the resident population of district 2 (3/1000 inhabitants), section 2 (14/1000). All 31 cooling towers of district 2 were analysed. L. pneumophila antigen (Binax Now) was detected in four towers, which were closed on 2 June. Only the strain isolated in a tower situated in section 2 of district 2 matched all five clinical isolates, as assessed by mAb and two genotyping methods, AFLP and PFGE. Eight days after closing the towers, new cases ceased appearing. Early detection and rapid coordinated medical and environmental actions permitted immediate control of the outbreak and probably contributed to the null case fatality.

Coenzyme Q and protein/lipid oxidation in a BSE-infected transgenic mouse model

Oxidative stress and antioxidants play an important role in neurodegenerative diseases. However, the exact participation of antioxidants in the evolution of prion diseases is still largely unknown. The aim of this study was to assess brain levels of coenzyme Q (CoQ), an endogenous lipophilic antioxidant, and the antioxidant/pro-oxidant status by determining oxidative damage to proteins and lipids after intracerebral bovine spongiform encephalopathy (BSE) infection of transgenic mice expressing bovine prion protein (PrP). Our results indicate that, whereas the ratio between the two CoQ homologues present in mice (CoQ(9) and CoQ(10)) is not altered by prion infection during the course of the disease, significant increases in total CoQ(9) and CoQ(10) were observed in BSE-infected mice 150 days after inoculation. This time point coincided with the first manifestation of PrP(Sc) deposition in nervous tissue. In addition, CoQ(9) and CoQ(10) levels, neuropathological alterations, and PrP(Sc) deposition in nervous tissues underwent further increases as the illness progressed. Lipid and protein oxidation were observed only at the final stage of the disease after clinical signs had appeared. These findings indicate upregulation of CoQ(9)- and CoQ(10)-dependent antioxidant systems in response to the increased oxidative stress induced by prion infection in nervous tissue. However, the induction of these endogenous antioxidant systems seems to be insufficient to prevent the development of the illness.

Reduced susceptibility to bovine spongiform encephalopathy prions in transgenic mice expressing a bovine PrP with five octapeptide repeats

In this work, transgenic (Tg) mice were generated expressing a bovine prion protein containing five octarepeats (BoPrP5OR-Tg). After intracerebral inoculation of bovine spongiform encephalopathy (BSE) inoculum, these mice suffered a BSE-like neuropathology but survived longer compared with homologous Tg mice expressing similar levels of a six octarepeat BoPrP protein (BoPrP6OR-Tg). De novo-generated five octarepeat (5OR) PrPSc showed no biochemical differences from 6OR-PrPSc, and the proteinase K-resistant core (PrPres) was biochemically indistinguishable from the 6OR counterpart. Lower susceptibility to BSE is suggested for BoPrP5OR-Tg mice, as they were not as efficient at replicating BSE prions from the same natural source inoculum as BoPrP6OR-Tg mice expressing similar PrPC levels. These results raise the possibility of selecting cattle breeds bearing the 5OR Prnp allele that are less susceptible to prion infection.

Changes in breast cancer mortality in Navarre (Spain) after introduction of a screening programme

OBJECTIVE

The aim of this study was to assess changes in the trend of breast cancer mortality in Navarre, and the effect that a screening programme may have had on these changes.

METHODS

A breast cancer screening programme targeting women aged 45-65 years was launched in Navarre in September 1990. Breast cancer deaths between 1975 and 2004 were identified from the Navarre Mortality Registry, and the date of diagnosis was obtained by linkage with the population-based Navarre Cancer Registry. We compared breast cancer mortality during the pre-screening (1987-89) and screening (2002-04) periods, and with the estimated rate in the last period calculated by a linear model with a Poisson distribution. The long-term trends (from 1975 through 2004) were described by joinpoint regression analysis. Prevalent cases (those diagnosed before 1991) were excluded to minimize dilution of the benefit in the post-screening period due to deaths from tumours diagnosed before screening began.

RESULTS

The joinpoint analysis showed a rising trend in breast cancer mortality rates until 1994, followed by a continual decrease of just over 5% per year. A comparison of mortality rates between the last pre-screening and the screening periods showed a decrease of 36% (95% confidence interval [CI] 21-48%), with the largest reduction in the 50-69 years age group (52%; CI: 33-65%). In this age group, mortality in the 2002-04 period was 62% lower than that projected from extrapolation of the pre-screening trend, while in unscreened age groups (30-44 and > or =75 years), mortality was only 22% lower. When prevalent tumours were excluded, the 50-69 years age group presented a further decrease in mortality than when all tumours were considered.

CONCLUSIONS

Fourteen years after the introduction of a screening programme, a major reduction in breast cancer mortality has been observed.

Progression of prion infectivity in asymptomatic cattle after oral bovine spongiform encephalopathy challenge

The presence of BSE prion infectivity in asymptomatic cattle and its tissue distribution are important concerns for both human and veterinary health and food safety. In this work, a collection of tissues from asymptomatic cattle challenged orally with BSE and culled at 20, 24, 27, 30 and 33 months have been used to inoculate intracerebrally BoPrP-Tg110 mice expressing bovine PrP to assess their infectivity. Results demonstrate that BSE infectivity in asymptomatic cattle is essentially restricted to the nervous system, Peyer's patches and tonsils, as reported previously for terminally BSE-diseased cattle. BSE infectivity was detectable in Peyer's patches and tonsils at all time points analysed, but infectivity in nervous tissues (brainstem and sciatic nerve) was only detectable after 27 months from inoculation. Infectivity in brainstem increased markedly at 33 months after inoculation. All other investigated tissues or fluids (spleen, skeletal muscle, blood and urine) revealed no detectable infectivity throughout the time course studied.

Perturbation of endoplasmic reticulum homeostasis facilitates prion replication

Prion diseases are fatal and infectious neurodegenerative disorders characterized by the accumulation of an abnormally folded form of the prion protein (PrP), termed PrP(Sc). Prion replication triggers endoplasmic reticulum (ER) stress, neuronal dysfunction, and apoptosis. In this study we analyze the effect of perturbations in ER homeostasis on PrP biochemical properties and prion replication. ER stress led to the generation of a mis-folded PrP isoform, which is detergent-insoluble and protease-sensitive. To understand the mechanism by which ER stress generates PrP misfolding, we assessed the contribution of different signaling pathways implicated in the unfolded protein response. Expression of a dominant negative form of IRE1 alpha or XBP-1 significantly increased PrP aggregation, whereas overexpression of ATF4 or an active mutant form of XBP-1 and ATF6 had the opposite affect. Analysis of prion replication in vitro revealed that the PrP isoform generated after ER stress is more efficiently converted into PrP(Sc) compared with the protein extracted from untreated cells. These findings indicate that ER-damaged cells might be more susceptible to prion replication. Because PrP(Sc) induces ER stress, our data point to a vicious cycle accelerating prion replication, which may explain the rapid progression of the disease.

Mumps outbreak in Navarre region, Spain, 2006-2007

More than 1300 cases of mumps were reported in Navarre, an autonomous community in northeast Spain, between August 2006 and January 2007. The first outbreak of 19 cases was reported on 10 August in Viana, a village with a population of 3860 people.

[Dealing with tuberculosis in primary care. Contact tracing procedures]

Although the number of cases of tuberculosis in Navarre has fallen in recent years, it is necessary to adapt the control programs to the new situation. The keys to advancing in its prevention and control are: obtaining an early diagnosis and an effective treatment of patients and detecting and treating people with a latent infection. Primary care plays an important role in both activities. Half of the cases of active tuberculosis that are diagnosed have been contacts by bacilliferous TB patients or else have had a high personal predisposition to developing the disease. That is why detection and treatment of the latent infection in our setting must be carried out: 1) through screening persons at high risk of becoming infected and developing the disease, and 2) trough a systematic study of contacts of persons with the disease. In the treatment of both active tuberculosis and latent infection it is essential to obtain good patient adherence.

[Epidemiology of tuberculosis in Navarre]

BACKGROUND

To describe the tendency and epidemiological characteristics of tuberculosis and estimate the prevalence of tuberculosis infection in Navarre. Methods. An analysis was made of the cases of tuberculosis reported in the 1993-2006 period, completed with microbiological information and data from other registries.

RESULTS

The incidence of tuberculosis in Navarre declined from 24.0 cases per 100,000 inhabitants in 1993 to 13.7 per 100,000 in 2006. Between 2000 and 2006 the incidence of tuberculosis fell by an annual 6.5% in those born in Spain and by an annual 9.3% in those born in other countries. In the 2004-2006 period, the diagnoses of tuberculosis were more frequent in males (60%), between the ages of 25 and 34 years (26.1%), and over 65 years of age (24.1%), and in persons born in Spain (69.0%). Four point three percent of the cases were coinfected with HIV. Six point six percent had had prior antituberculosis treatment, 5.4% showed resistance to some antituberculosis drug, and 2.3% resistance to more than one. There was a predominance of pulmonary forms (68.9%) and 37% of the total had positive sputum bacilloscopy. Death occurred in 6.2% of the cases before treatment was finalised. Between 2004 and 2006 15 clusters of cases were detected, 11 amongst cohabitants. Ninety-three percent of the secondary cases occurred from index cases born in Spain.

CONCLUSION

There has been a notable advance in the control of tuberculosis, both in the native population and in that from other countries, although there is still room for improvement.

Isolation and characterization of a proteinase K-sensitive PrPSc fraction

Recent studies have shown that a sizable fraction of PrPSc present in prion-infected tissues is, contrary to previous conceptions, sensitive to digestion by proteinase K (PK). This finding has important implications in the context of diagnosis of prion disease, as PK has been extensively used in attempts to distinguish between PrPSc and PrPC. Even more importantly, PK-sensitive PrPSc (sPrPSc) might be essential to understand the process of conversion and aggregation of PrPC leading to infectivity. We have isolated a fraction of sPrPSc. This material was obtained by differential centrifugation at an intermediate speed of Syrian hamster PrPSc obtained through a conventional procedure based on ultracentrifugation in the presence of detergents. PK-sensitive PrPSc is completely degraded under standard conditions (50 mug/mL of proteinase K at 37 degrees C for 1 h) and can also be digested with trypsin. Centrifugation in a sucrose gradient showed sPrPSc to correspond to the lower molecular weight fractions of the continuous range of oligomers that constitute PrPSc. PK-sensitive PrPSc has the ability to convert PrPC into protease-resistant PrPSc, as assessed by the protein misfolding cyclic amplification assay (PMCA). Limited proteolysis of sPrPSc using trypsin allows for identification of regions that are particularly susceptible to digestion, i.e., are partially exposed and flexible; we have identified as such the regions around residues K110, R136, R151, K220, and R229. PK-sensitive PrPSc isolates should prove useful for structural studies to help understand fundamental issues of the molecular biology of PrPSc and in the quest to design tests to detect preclinical prion disease.

Sheep-passaged bovine spongiform encephalopathy agent exhibits altered pathobiological properties in bovine-PrP transgenic mice

Sheep can be experimentally infected with bovine spongiform encephalopathy (BSE), and the ensuing disease is similar to scrapie in terms of pathogenesis and clinical signs. BSE infection in sheep is an animal and human health concern. In this study, the transmission in BoPrP-Tg110 mice of prions from BSE-infected sheep was examined and compared to the transmission of original cattle BSE in cattle and sheep scrapie prions. Our results indicate no transmission barrier for sheep BSE prions to infect BoPrP-Tg110 mice, but the course of the disease is accelerated compared to the effects of the original BSE isolate. The shortened incubation period of sheep BSE in the model was conserved in subsequent passage in BoPrP-Tg110 mice, indicating that it is not related to infectious titer differences. Biochemical signature, lesion profile, and PrP(Sc) deposition pattern of both cattle and sheep BSE were similar. In contrast, all three sheep scrapie isolates tested showed an evident transmission barrier and further adaptation in subsequent passage. Taken together, those data indicate that BSE agent can be altered by crossing a species barrier, raising concerns about the virulence of this new prion towards other species, including humans. The BoPrP-Tg110 mouse bioassay should be considered as a valuable tool for discriminating scrapie and BSE in sheep.

Ultra-efficient replication of infectious prions by automated protein misfolding cyclic amplification

Prions are the unconventional infectious agents responsible for transmissible spongiform encephalopathies, which appear to be composed mainly or exclusively of the misfolded prion protein (PrPSc). Prion replication involves the conversion of the normal prion protein (PrPC) into the misfolded isoform, catalyzed by tiny quantities of PrPSc present in the infectious material. We have recently developed the protein misfolding cyclic amplification (PMCA) technology to sustain the autocatalytic replication of infectious prions in vitro. Here we show that PMCA enables the specific and reproducible amplification of exceptionally minute quantities of PrPSc. Indeed, after seven rounds of PMCA, we were able to generate large amounts of PrPSc starting from a 1x10(-12) dilution of scrapie hamster brain, which contains the equivalent of approximately 26 molecules of protein monomers. According to recent data, this quantity is similar to the minimum number of molecules present in a single particle of infectious PrPSc, indicating that PMCA may enable detection of as little as one oligomeric PrPSc infectious particle. Interestingly, the in vitro generated PrPSc was infectious when injected in wild-type hamsters, producing a disease identical to the one generated by inoculation of the brain infectious material. The unprecedented amplification efficiency of PMCA leads to a several billion-fold increase of sensitivity for PrPSc detection as compared with standard tests used to screen prion-infected cattle and at least 4000 times more sensitivity than the animal bioassay. Therefore, PMCA offers great promise for the development of highly sensitive, specific, and early diagnosis of transmissible spongiform encephalopathy and to further understand the molecular basis of prion propagation.

Presymptomatic detection of prions in blood

Prions are thought to be the proteinaceous infectious agents responsible for transmissible spongiform encephalopathies (TSEs). PrP(Sc), the main component of the infectious agent, is also the only validated surrogate marker for the disease, and its sensitive detection is critical for minimizing the spread of the disease. We detected PrP(Sc) biochemically in the blood of hamsters infected with scrapie during most of the presymptomatic phase of the disease. At early stages of the incubation period, PrP(Sc) detected in blood was likely to be from the peripheral replication of prions, whereas at the symptomatic phase, PrP(Sc) in blood was more likely to have leaked from the brain. The ability to detect prions biochemically in the blood of infected but not clinically sick animals offers a great promise for the noninvasive early diagnosis of TSEs.

Cell expression of a four extra octarepeat mutated PrPCmodifies cell structure and cell cycle regulation

RK13 cell lines generated to express bovine PrP(C) with a four extra octarepeat insertional mutation (Bo-10ORPrP(C)) show partially insoluble PrP(C) and lower rates of cell growth when compared to either the same cells expressing wild type Bo-6ORPrP(C) or the original RK13 cell line. The expression of Bo-10ORPrP(C) in cell cultures was also associated with changes in cell size and reorganization of the actin cytoskeleton. This last process was reversed by Clostridium difficile toxin-B, a specific inhibitor of small GTPase proteins. Further, in clones expressing Bo-10ORPrP(C), increased proportions of cells at cell cycle stage G2/M were observed. Proteasome inhibitors caused a further expansion of G2/M-stage cells that was more marked in cell lines expressing Bo-10ORPrP(C) than those expressing Bo-6ORPrP(C), while this effect was minimal or null in the original RK13 cell line. Hence, the presence of Bo-10ORPrP(C) in RK13 cells promotes cell cycle arrest at G2/M, and the effect is amplified by proteasome inhibition. These findings suggest a role for PrP(C) in cell morphology and cell cycle regulation, and open new avenues for understanding the mechanisms underlying PrP mutation-associated diseases.

Current legionellosis outbreak with 139 cases in Pamplona, Spain

By 8 June 2006, 139 cases of legionellosis had been reported in an outbreak in Pamplona, north Spain.