Synanthropy of Wild Mammals as a Determinant of Emerging Infectious Diseases in the Asian–Australasian Region

Humans create ecologically simplified landscapes that favour some wildlife species, but not others. Here, we explore the possibility that those species that tolerate or do well in human-modified environments, or 'synanthropic' species, are predominantly the hosts of zoonotic emerging and re-emerging infectious diseases (EIDs). We do this using global wildlife conservation data and wildlife host information extracted from systematically reviewed emerging infectious disease literature. The evidence for this relationship is examined with special emphasis on the Australasian, South East Asian and East Asian regions. We find that synanthropic wildlife hosts are approximately 15 times more likely than other wildlife in this region to be the source of emerging infectious diseases, and this association is essentially independent of the taxonomy of the species. A significant positive association with EIDs is also evident for those wildlife species of low conservation risk. Since the increase and spread of native and introduced species able to adapt to human-induced landscape change is at the expense of those species most vulnerable to habitat loss, our findings suggest a mechanism linking land conversion, global decline in biodiversity and a rise in EIDs of wildlife origin.     

Evaluation of the National Notifiable Diseases Surveillance System for Dengue Fever in Taiwan, 2010–2012

BackgroundIn Taiwan, around 1,500 cases of dengue fever are reported annually and incidence has been increasing over time. A national web-based Notifiable Diseases Surveillance System (NDSS) has been in operation since 1997 to monitor incidence and trends and support case and outbreak management. We present the findings of an evaluation of the NDSS to ascertain the extent to which dengue fever surveillance objectives are being achieved.MethodologyWe extracted the NDSS data on all laboratory-confirmed dengue fever cases reported during 1 January 2010 to 31 December 2012 to assess and describe key system attributes based on the Centers for Disease Control and Prevention surveillance evaluation guidelines. The system’s structure and processes were delineated and operational staff interviewed using a semi-structured questionnaire. Crude and age-adjusted incidence rates were calculated and key demographic variables were summarised to describe reporting activity. Data completeness and validity were described across several variables.Conclusions/SignificanceThe NDSS for dengue fever surveillance is a robust, well maintained and acceptable system that supports the collection of complete and valid data needed to achieve the surveillance objectives. The simplicity of the system engenders compliance leading to timely and accurate reporting. Completeness of hospitalization information could be further improved to allow assessment of severity of illness. To minimize misclassification, an algorithm to accurately classify travel cases should be established.     

Sentinel Surveillance of Influenza-Like Illness in Two Hospitals in Maracay,Venezuela: 2006–2010

Background

Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela.

Methodology/Principal Findings

We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month – 86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second - higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected.

Conclusions/Significance

Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial appearance in 2009. Seasonal influenza A/H3N2 was the most common influenza virus in the post-pandemic phase.     

Conservation and Wildlife Management in South African National Parks 1930s–1960s

In recent decades conservation biology has achieved a high position among the sciences. This is certainly true of South Africa, a small country, but the third most biodiverse in the world. This article traces some aspects of the transformation of South African wildlife management during the 1930s to the 1960s from game reserves based on custodianship and the “balance of nature” into scientifically managed national parks with a philosophy of “command and control” or “management by intervention.” In 1910 the four British colonies had formed the Union of South Africa, and by the 1920s there was wide acceptance of national parks, a development influenced by their success in the United States. It was not, however, until after the Second World War, that management of the expanding conservation estate altered from a rather unsystematic laissez faire variety, into more scientifically informed management practices with an efficient bureaucracy in charge. This was achieved by modifications in organizational structures and institutional cultures initiated by a change of government in 1948 which, this article argues, impacted in turn on wildlife management and shaped and professionalized many aspects of that field science. “Management by intervention” was the hallmark of South African wildlife and conservation biology from the 1960s until recently, when there have been shifts towards “adaptive resource management” in a period of further change in the country’s politics.     

Influenza in Outpatient ILI Case-Patients in National Hospital-Based Surveillance,Bangladesh, 2007–2008

Background

Recent population-based estimates in a Dhaka low-income community suggest that influenza was prevalent among children. To explore the epidemiology and seasonality of influenza throughout the country and among all age groups, we established nationally representative hospital-based surveillance necessary to guide influenza prevention and control efforts.

Methodolgy/Principal Findings

We conducted influenza-like illness and severe acute respiratory illness sentinel surveillance in 12 hospitals across Bangladesh during May 2007–December 2008. We collected specimens from 3,699 patients, 385 (10%) which were influenza positive by real time RT-PCR. Among the sample-positive patients, 192 (51%) were type A and 188 (49%) were type B. Hemagglutinin subtyping of type A viruses detected 137 (71%) A/H1 and 55 (29%) A/H3, but no A/H5 or other novel influenza strains. The frequency of influenza cases was highest among children aged under 5 years (44%), while the proportions of laboratory confirmed cases was highest among participants aged 11–15 (18%). We applied kriging, a geo-statistical technique, to explore the spatial and temporal spread of influenza and found that, during 2008, influenza was first identified in large port cities and then gradually spread to other parts of the country. We identified a distinct influenza peak during the rainy season (May–September).

Conclusions/Significance

Our surveillance data confirms that influenza is prevalent throughout Bangladesh, affecting a wide range of ages and causing considerable morbidity and hospital care. A unimodal influenza seasonality may allow Bangladesh to time annual influenza prevention messages and vaccination campaigns to reduce the national influenza burden. To scale-up such national interventions, we need to quantify the national rates of influenza and the economic burden associated with this disease through further studies.     

Is the Social–Ecological Framework Useful in Understanding Infectious Diseases? The Case of HIV/AIDS

The extraordinary complexity of emerging infectious diseases calls for new paradigms and approaches to understand the casual mechanisms underlying pathogen emergence and to improve disease prevention. An attempt was made to foster interdisciplinary collaboration and stimulate transdisciplinary approaches to improve emerging infectious disease research during and subsequent to a meeting held in March 2005 as part of the US NIH Roadmap initiative “Research Teams of the Future.” The meeting drew on models and theories associated with the idea of humans and nature as interactive, complex systems. Of the three diseases chosen as case studies to represent the wide range of social and ecological emergence factors involved (dengue, leptospirosis, and HIV/AIDS), HIV/AIDS proved especially difficult. This Profile examines the meeting themes with a particular focus on the deliberations of a working group focused on HIV/AIDS. Attention is given to the challenges of bridging different disciplines and perspectives in applying a social-ecological framework to analyze HIV/AIDS and the benefits of reductionistic vs. holistic strategies in responding to the global HIV/AIDS pandemic. The issues raised point to opportunities to significantly deepen understanding of HIV/AIDS as a transdisciplinary problem. Disclaimer: The author is Director of the Research Program at the East–West Center and was chair of the HIV/AIDS mini-symposium. This Profile is based on the important contributions and efforts of all the members of the HIV/AIDS working group. All omissions or misrepresentations are the author’s.     

Lipid Body–Phagosome Interaction in Macrophages during Infectious Diseases: Host Defense or Pathogen Survival Strategy?

Phagocytosis of invading microorganisms by specialized cells such as macrophages and neutrophils is a key component of the innate immune response. These cells capture and engulf pathogens and subsequently destroy them in intracellular vacuoles—the phagosomes. Pathogen phagocytosis and progression and maturation of pathogen-containing phagosomes, a crucial event to acquire microbicidal features, occurs in parallel with accentuated formation of lipid-rich organelles, termed lipid bodies (LBs), or lipid droplets. Experimental and clinical infections with different pathogens such as bacteria, parasites, and viruses induce LB accumulation in cells from the immune system. Within these cells, LBs synthesize and store inflammatory mediators and are considered structural markers of inflammation. In addition to LB accumulation, interaction of these organelles with pathogen-containing phagosomes has increasingly been recognized in response to infections and may have implications in the outcome or survival of the microorganism within host cells. In this review, we summarize our current knowledge on the LB-phagosome interaction within cells from the immune system, with emphasis on macrophages, and discuss the functional meaning of this event during infectious diseases.     

Plant–Soil Feedbacks Contribute to the Persistence of Bromus inermis in Tallgrass Prairie

As invasive plants become a greater threat to native ecosystems, we need to improve our understanding of the factors underlying their success and persistence. Over the past 30 years, the C₃ nonnative plant Bromus inermis (smooth brome) has been spreading throughout the central grasslands in North America. Invasion by this grass has resulted in the local displacement of natives, including the tallgrass species Panicum virgatum (switchgrass). To determine if factors related to resource availability and plant–soil interactions were conferring a competitive advantage on smooth brome, field plots were set up under varying nitrogen (N) levels. Plots composed of a 1:1 ratio of smooth brome and switchgrass were located in a restored tallgrass prairie and were randomly assigned one of the following three N levels: (a) NH₄NO₃ added to increase available N, (b) sucrose added to reduce available N, and (c) no additions to serve as control. In addition, soil N status, soil respiration rates, plant growth, and litter decomposition rates were monitored. Results indicate that by the 2nd year, the addition of sucrose significantly reduced available soil N and additions of NH₄NO₃ increased it. Further, smooth brome had greater tiller density, mass, and canopy interception of light on N-enriched soils, whereas none of these characteristics were stimulated by added N in the case of switchgrass. This suggests that smooth brome may have a competitive advantage on higher-N soils. Smooth-brome plant tissue also had a lower carbon–nitrogen (C:N) ratio and a higher decomposition rate than switchgrass and thus may cycle N more rapidly in the plant–soil system. These differences suggest a possible mechanism for the persistence of smooth brome in the tallgrass prairie: Efficient recycling of nutrient-rich litter under patches of smooth brome may confer a competitive advantage that enables it to persist in remnant or restored prairies. Increased N deposition associated with human activity and changing land use may play a critical role in the persistence of smooth brome and other N-philic exotic species.     

Peptide Similarity Search Based and Virtual Screening Based Strategies to Identify Small Molecules to Inhibit CarD–RNAP Interaction in M. tuberculosis

International Journal of Peptide Research and Therapeutics - Inhibition of protein–protein interaction is considered as an innovative approach in the drug development field. In the present...     

Host–endoparasitoid–endosymbiont relationships: concealed Strepsiptera provide new twist to Wolbachia in Australian tephritid fruit flies

Wolbachia are widespread endosymbionts that affect arthropod reproduction and fitness. Mostly maternally inherited, Wolbachia are occasionally transferred horizontally. Previously, two Wolbachia strains were reported at low prevalence and titres across seven Australian tephritid species, possibly indicative of frequent horizontal transfer. Here, we performed whole-genome sequencing of field-caught Wolbachia-positive flies. Unexpectedly, we found complete mitogenomes of an endoparasitic strepsipteran, Dipterophagus daci, suggesting that Wolbachia in the flies are linked to concealed parasitization. We performed the first genetic characterization of D. daci and detected D. daci in Wolbachia-positive flies not visibly parasitized, and most but not all Wolbachia-negative flies were D. daci-negative, presumably reflecting polymorphism for the Wolbachia infections in D. daci. We dissected D. daci from stylopized flies and confirmed that Wolbachia infects D. daci, but also found Wolbachia in stylopized fly tissues, likely somatic, horizontally transferred, non-heritable infections. Furthermore, no Wolbachia cif and wmk genes were detected and very low mitogenomic variation in D. daci across its distribution. Therefore, Wolbachia may influence host fitness without reproductive manipulation. Our study of 13 tephritid species highlights that concealed early stages of strepsipteran parasitization led to the previous incorrect assignment of Wolbachia co-infections to tephritid species, obscuring ecological studies of this common endosymbiont and its horizontal transmission by parasitoids.     

Emerging resistance among bacterial pathogens in the intensive care unit – a European and North American Surveillance study (2000–2002)

Background

Globally ICUs are encountering emergence and spread of antibiotic-resistant pathogens and for some pathogens there are few therapeutic options available.

Methods

Antibiotic in vitro susceptibility data of predominant ICU pathogens during 2000–2 were analyzed using data from The Surveillance Network (TSN) Databases in Europe (France, Germany and Italy), Canada, and the United States (US).

Results

Oxacillin resistance rates among Staphylococcus aureus isolates ranged from 19.7% to 59.4%. Penicillin resistance rates among Streptococcus pneumoniae varied from 2.0% in Germany to as high as 20.2% in the US; however, ceftriaxone resistance rates were comparably lower, ranging from 0% in Germany to 3.4% in Italy. Vancomycin resistance rates among Enterococcus faecalis were ≤ 4.5%; however, among Enterococcus faecium vancomycin resistance rates were more frequent ranging from 0.8% in France to 76.3% in the United States. Putative rates of extended-spectrum β-lactamase (ESBL) production among Enterobacteriaceae were low, <6% among Escherichia coli in the five countries studied. Ceftriaxone resistance rates were generally lower than or similar to piperacillin-tazobactam for most of the Enterobacteriaceae species examined. Fluoroquinolone resistance rates were generally higher for E. coli (6.5% – 13.9%), Proteus mirabilis (0–34.7%), and Morganella morganii (1.6–20.7%) than other Enterobacteriaceae spp (1.5–21.3%). P. aeruginosa demonstrated marked variation in β-lactam resistance rates among countries. Imipenem was the most active compound tested against Acinetobacter spp., based on resistance rates.

Conclusion

There was a wide distribution in resistance patterns among the five countries. Compared with other countries, Italy showed the highest resistance rates to all the organisms with the exception of Enterococcus spp., which were highest in the US. This data highlights the differences in resistance encountered in intensive care units in Europe and North America and the need to determine current local resistance patterns by which to guide empiric antimicrobial therapy for intensive care infections.     

Deaths Ascribed to Non-Communicable Diseases among Rural Kenyan Adults Are Proportionately Increasing: Evidence from a Health and Demographic Surveillance System, 2003–2010

Background

Non-communicable diseases (NCDs) result in more deaths globally than other causes. Monitoring systems require strengthening to attribute the NCD burden and deaths in low and middle-income countries (LMICs). Data from health and demographic surveillance systems (HDSS) can contribute towards this goal.

Methods and Findings

Between 2003 and 2010, 15,228 deaths in adults aged 15 years (y) and older were identified retrospectively using the HDSS census and verbal autopsy in rural western Kenya, attributed into broad categories using InterVA-4 computer algorithms; 37% were ascribed to NCDs, 60% to communicable diseases (CDs), 3% to injuries, and <1% maternal causes. Median age at death for NCDs was 66y and 71y for females and males, respectively, with 43% (39% male, 48% female) of NCD deaths occurring prematurely among adults aged below 65y. NCD deaths were mainly attributed to cancers (35%) and cardio-vascular diseases (CVDs; 29%). The proportionate mortality from NCDs rose from 35% in 2003 to 45% in 2010 (χ² linear trend 93.4; p<0.001). While overall annual mortality rates (MRs) for NCDs fell, cancer-specific MRs rose from 200 to 262 per 100,000 population, mainly due to increasing deaths in adults aged 65y and older, and to respiratory neoplasms in all age groups. The substantial fall in CD MRs resulted in similar MRs for CDs and NCDs among all adult females by 2010. NCD MRs for adults aged 15y to <65y fell from 409 to 183 per 100,000 among females and from 517 to 283 per 100,000 population among males. NCD MRs were higher among males than females aged both below, and at or above, 65y.

Conclusions

NCDs constitute a significant proportion of deaths in rural western Kenya. Evidence of the increasing contribution of NCDs to overall mortality supports international recommendations to introduce or enhance prevention, screening, diagnosis and treatment programmes in LMICs.     

Population Based National Tuberculosis Prevalence Survey among Adults (>15 Years) in Pakistan, 2010–2011

Background

We aimed to determine the prevalence of pulmonary tuberculosis (TB) amongst the adult population in 2010–2011 in Pakistan.

Method

A nationwide cross-sectional survey with multistage cluster sampling was conducted among adults (≥15 years) in 95 clusters in 2010–2011. All consenting participants were screened for cough and by chest X-ray. Participants with presumptive TB submitted two sputum samples for smear microscopy, culture, and molecular testing if needed. The TB prevalence estimates were adjusted for missing data and the cluster design.

Result

Of 131,329 eligible individuals, 105,913 (81%) participated in the survey, of whom 10,471 (9.9%) were eligible for sputum examination. We found 341 bacteriologically positive TB cases of whom 233 had sputum smear-positive TB. The adjusted prevalence estimates for smear and bacteriologically positive TB were 270/100,000 (95% confidence interval (CI) 217–323), and 398/100,000 (95% CI 333–463), respectively. Only 61% of the diagnosed TB cases screened positive on symptoms (cough >2wks), whereas the other TB cases were detected based on X-ray abnormalities. The TB prevalence increased with age and was 1.8 times higher among men than women. The prevalence-to-notification ratio of smear-positive TB was 3.1 (95% CI 2.5–3.7), was higher among men than women, and increased with age.

Conclusion

Our data suggest that there is under-detection and/or -notification of TB, especially among men and elderly. TB control should be strengthened specifically in these risk groups. X-ray examination should be combined with symptom screening to enhance case detection.     

Surveillance of the Incidence of Non-Communicable Diseases (NCDs) with Sparse Resources: A Simulation Study Using Data from a National Diabetes Registry,Denmark, 1995–2004

We propose two new methods to estimate secular trends in the incidence of a chronic disease from a series of prevalence studies and mortality data. One method is a direct inversion formula, the second method is a least squares estimation. Both methods are validated in a simulation study based on data from a diabetes register. The results of the validation show that the proposed methods may be useful in epidemiological settings with sparse resources, where running a register or a series of follow-up studies is difficult or impossible.     

GluA4 Dependent Plasticity Mechanisms Contribute to Developmental Synchronization of the CA3–CA1 Circuitry in the Hippocampus

During the course of development, molecular mechanisms underlying activity-dependent synaptic plasticity change considerably. At immature CA3–CA1 synapses in the hippocampus, PKA-driven synaptic insertion of GluA4 AMPA receptors is the predominant mechanism for synaptic strengthening. However, the physiological significance of the developmentally restricted GluA4-dependent plasticity mechanisms is poorly understood. Here we have used microelectrode array (MEA) recordings in GluA4 deficient slice cultures to study the role of GluA4 in early development of the hippocampal circuit function. We find that during the first week in culture (DIV2–6) when GluA4 expression is restricted to pyramidal neurons, loss of GluA4 has no effect on the overall excitability of the immature network, but significantly impairs synchronization of the CA3 and CA1 neuronal populations. In the absence of GluA4, the temporal correlation of the population spiking activity between CA3–CA1 neurons was significantly lower as compared to wild-types at DIV6. Our data show that synapse-level defects in transmission and plasticity mechanisms are efficiently compensated for to normalize population firing rate at the immature hippocampal network. However, lack of the plasticity mechanisms typical for the immature synapses may perturb functional coupling between neuronal sub-populations, a defect frequently implicated in the context of developmentally originating neuropsychiatric disorders.

     

Australian Gay and Bisexual Men’s Attitudes to HIV Treatment as Prevention in Repeated,National Surveys, 2011-2013

Objective

Assess the acceptability of HIV treatment as prevention and early antiretroviral treatment among gay and bisexual men in Australia and any changes in attitudes over time.

Methods

National, online, cross-sectional surveys of gay and bisexual men were repeated in 2011 and 2013. Changes in attitudes to HIV treatment over time were assessed with multivariate analysis of variance. The characteristics of men who agreed that HIV treatment prevented transmission and thought that early treatment was necessary were identified with multivariate logistic regression.

Results

In total, 2599 HIV-negative, untested and HIV-positive men participated (n = 1283 in 2011 and n = 1316 in 2013). Attitudes changed little between 2011 and 2013; most participants remained sceptical about the preventative benefits of HIV treatment. In 2013, only 2.6% of men agreed that HIV treatment prevented transmission; agreement was associated with being HIV-positive, having an HIV-positive regular partner, and having received HIV post-exposure prophylaxis. In contrast, 71.8% agreed that early antiretroviral treatment is necessary; younger men were more likely and HIV-positive men and participants with HIV-positive partners were much less likely to agree with this.

Conclusions

Promoting the individual health benefits of HIV treatment rather than its preventative benefits remains more acceptable to Australian gay and bisexual men.