Ultrashort-range, high-frequency communication by female mice shapes social interactions

Animals engage in complex social encounters that influence social groups and resource allocation. During these encounters, acoustic signals, used at both short and long ranges, play pivotal roles in regulating the behavior of conspecifics. Mice, for instance, emit ultrasonic vocalizations, signals above the range of human hearing, during close-range social interactions. How these signals shape behavior, however, is unknown due to the difficulty in discerning which mouse in a group is vocalizing. To overcome this impediment, we used an eight-channel microphone array system to determine which mouse emitted individual vocal signals during 30 minutes of unrestrained social interaction between a female and a single male or female conspecific. Females modulated both the timing and context of vocal emission based upon their social partner. Compared to opposite-sex pairings, females in same-sex pairs vocalized when closer to a social partner and later in the 30 minutes of social engagement. Remarkably, we found that female mice exhibited no immediate changes in acceleration (movement) to male-emitted vocal signals. Both males and females, in contrast, modulated their behavior following female-emitted vocal signals in a context-dependent manner. Thus, our results suggest female vocal signals function as a means of ultrashort-range communication that shapes mouse social behavior.

Carbon dioxide binary crystals via the thermal decomposition of RDX at high pressure

A carbon dioxide and nitrous oxide solid solution has been captured in a diamond anvil cell following the thermal decomposition of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) at high temperatures and pressures. This is the first time a carbon dioxide binary solid has been observed at high pressure. This observation has stimulated low temperature crystallographic studies of this binary system using recently developed gas absorption apparatus and computational modelling.

Incidence of invasive salmonella disease in sub-Saharan Africa: a multicentre population-based surveillance study

BACKGROUND

Available incidence data for invasive salmonella disease in sub-Saharan Africa are scarce. Standardised, multicountry data are required to better understand the nature and burden of disease in Africa. We aimed to measure the adjusted incidence estimates of typhoid fever and invasive non-typhoidal salmonella (iNTS) disease in sub-Saharan Africa, and the antimicrobial susceptibility profiles of the causative agents.

METHODS

We established a systematic, standardised surveillance of blood culture-based febrile illness in 13 African sentinel sites with previous reports of typhoid fever: Burkina Faso (two sites), Ethiopia, Ghana, Guinea-Bissau, Kenya, Madagascar (two sites), Senegal, South Africa, Sudan, and Tanzania (two sites). We used census data and health-care records to define study catchment areas and populations. Eligible participants were either inpatients or outpatients who resided within the catchment area and presented with tympanic (≥38·0°C) or axillary temperature (≥37·5°C). Inpatients with a reported history of fever for 72 h or longer were excluded. We also implemented a health-care utilisation survey in a sample of households randomly selected from each study area to investigate health-seeking behaviour in cases of self-reported fever lasting less than 3 days. Typhoid fever and iNTS disease incidences were corrected for health-care-seeking behaviour and recruitment.

FINDINGS

Between March 1, 2010, and Jan 31, 2014, 135 Salmonella enterica serotype Typhi (S Typhi) and 94 iNTS isolates were cultured from the blood of 13 431 febrile patients. Salmonella spp accounted for 33% or more of all bacterial pathogens at nine sites. The adjusted incidence rate (AIR) of S Typhi per 100 000 person-years of observation ranged from 0 (95% CI 0-0) in Sudan to 383 (274-535) at one site in Burkina Faso; the AIR of iNTS ranged from 0 in Sudan, Ethiopia, Madagascar (Isotry site), and South Africa to 237 (178-316) at the second site in Burkina Faso. The AIR of iNTS and typhoid fever in individuals younger than 15 years old was typically higher than in those aged 15 years or older. Multidrug-resistant S Typhi was isolated in Ghana, Kenya, and Tanzania (both sites combined), and multidrug-resistant iNTS was isolated in Burkina Faso (both sites combined), Ghana, Kenya, and Guinea-Bissau.

INTERPRETATION

Typhoid fever and iNTS disease are major causes of invasive bacterial febrile illness in the sampled locations, most commonly affecting children in both low and high population density settings. The development of iNTS vaccines and the introduction of S Typhi conjugate vaccines should be considered for high-incidence settings, such as those identified in this study.

FUNDING

Bill & Melinda Gates Foundation.

The Typhoid Fever Surveillance in Africa Program (TSAP): Clinical, Diagnostic, and Epidemiological Methodologies

BACKGROUND

New immunization programs are dependent on data from surveillance networks and disease burden estimates to prioritize target areas and risk groups. Data regarding invasive Salmonella disease in sub-Saharan Africa are currently limited, thus hindering the implementation of preventive measures. The Typhoid Fever Surveillance in Africa Program (TSAP) was established by the International Vaccine Institute to obtain comparable incidence data on typhoid fever and invasive nontyphoidal Salmonella (iNTS) disease in sub-Saharan Africa through standardized surveillance in multiple countries.

METHODS

Standardized procedures were developed and deployed across sites for study site selection, patient enrolment, laboratory procedures, quality control and quality assurance, assessment of healthcare utilization and incidence calculations.

RESULTS

Passive surveillance for bloodstream infections among febrile patients was initiated at thirteen sentinel sites in ten countries (Burkina Faso, Ethiopia, Ghana, Guinea-Bissau, Kenya, Madagascar, Senegal, South Africa, Sudan, and Tanzania). Each TSAP site conducted case detection using these standardized methods to isolate and identify aerobic bacteria from the bloodstream of febrile patients. Healthcare utilization surveys were conducted to adjust population denominators in incidence calculations for differing healthcare utilization patterns and improve comparability of incidence rates across sites.

CONCLUSIONS

By providing standardized data on the incidence of typhoid fever and iNTS disease in sub-Saharan Africa, TSAP will provide vital input for targeted typhoid fever prevention programs.

Non-equilibrium cobalt(iii) "click" capsules

Cobalt(iii) tetrahedral capsules have been prepared using an assembly-followed-by-oxidation protocol from a cobalt(ii) precursor and a readily derivatizable pyridyl-triazole ligand system. Experiments designed to probe the constitutional dynamics show that these architectures are in a non-equilibrium state. A preliminary investigation into the host-guest chemistry of a water-soluble derivative shows it can bind and differentiate a range of different neutral organic molecules. The stability of this ensemble also permits the study of guest-binding at high salt concentrations.

Adherence to highly active antiretroviral therapy (HAART): a meta-analysis

This meta-analysis synthesizes eighty-four observational studies, conducted across twenty countries, to determine the mean proportion of people who reported ≥90% adherence to prescribed highly active antiretroviral therapy (HAART) and to identify the factors associated with high levels of adherence. Eight electronic databases were searched to locate all relevant studies available by January 2010, which were then coded for sample characteristics and adherence levels. The average rate of reporting ≥90% adherent HAART adherence is 62%. However, this proportion varies greatly across studies. In particular, a greater proportion of individuals maintaining ≥90% adherence to HAART is more likely in studies with higher proportions of men who have sex with men (MSM) and lower proportions of injection drug users (IDU), with participants in an earlier stage of infection, and in studies conducted in countries characterized by lower Human Development Index (HDI) scores.

A meta-analysis of the efficacy of HIV/AIDS prevention interventions in Asia, 1995-2009

The HIV/AIDS epidemic continues to grow in pockets across Asia, despite early successes at curtailing its spread in countries like Thailand. Recent evidence documents dramatic increases in incidence among risk groups and, alarmingly, the general population. This meta-analysis summarizes the sexual risk-reduction interventions for the prevention of HIV-infection that have been evaluated in Asia. Sexual risk-reduction outcomes (condom use, number of sexual partners, incident sexually transmitted infections [STI], including HIV) from 46 behavioral intervention studies with a comparison condition and available by August 2010 were included. Overall, behavioral interventions in Asia consistently reduced sexual risk outcomes. Condom use improved when interventions sampled more women, included motivational content, or did not include STI testing and treatment. Incident HIV/STI efficacy improved most when interventions sampled more women, were conducted more recently, or when they included STI counseling and testing. Sexual frequency efficacy improved more in interventions that were conducted in countries with lower human development capacities, when younger individuals were sampled, or when condom skills training was included. Behavioral interventions for reducing sexual risk in Asia are efficacious; yet, the magnitude of the effects co-varies with specific intervention and structural components. The impact of structural factors on HIV intervention efficacy must be considered when implementing and evaluating behavioral interventions. Implications and recommendations for HIV/AIDS interventions are discussed.

Efficacy of HIV prevention interventions in Latin American and Caribbean nations, 1995-2008: a meta-analysis

This meta-analysis synthesized 37 HIV prevention interventions (from 28 studies) that were evaluated in Latin American and Caribbean nations. These studies were obtained through systematic searches of English, Spanish, and Portuguese-language databases available as of January 2009. Overall, interventions significantly increased knowledge (d = 0.40) and condom use (d = 0.25) but the effects varied widely. Interventions produced more condom use when they focused on high-risk individuals, distributed condoms, and explicitly addressed social-cultural components. The best-fitting models utilized factors related to geography, especially indices of a nations' human development index (HDI) and income inequality (i.e., Gini index). Interventions that provided at least 3 h of content succeeded better when HDI and income inequality were lower, suggesting that intensive HIV prevention activities succeed best where the need is greatest. Implications for HIV intervention development in Latin America and the Caribbean are discussed.

A network-individual-resource model for HIV prevention

HIV is transmitted through dyadic exchanges of individuals linked in transitory or permanent networks of varying sizes. A theoretical perspective that bridges key individual level elements with important network elements can be a complementary foundation for developing and implementing HIV interventions with outcomes that are more sustainable over time and have greater dissemination potential. Toward that end, we introduce a Network-Individual-Resource (NIR) model for HIV prevention that recognizes how exchanges of resources between individuals and their networks underlies and sustains HIV-risk behaviors. Individual behavior change for HIV prevention, then, may be dependent on increasing the supportiveness of that individual's relevant networks for such change. Among other implications, an NIR model predicts that the success of prevention efforts depends on whether the prevention efforts (1) prompt behavior changes that can be sustained by the resources the individual or their networks possess; (2) meet individual and network needs and are consistent with the individual's current situation/developmental stage; (3) are trusted and valued; and (4) target high HIV-prevalence networks.

What is the prognosis of mild normocytic anaemia in older people?

BACKGROUND

There is reduced survival for people with all types of anaemia and it has been shown that there is a low yield from investigations for older people with normocytic anaemia. However, the longer-term outcomes of people with mild normocytic anaemia are not known.

AIMS

To determine the 5-year prognosis of older people with mild normocytic anaemia, compared with non-anaemic controls.

METHODS

This was a prospective cohort study, with some retrospective data collection, comparing 52 people aged > or =65 years (haemoglobin 100-119 g/L; mean cell volume 80-99 fL) without an obvious cause at presentation with 52 non-anaemic controls. The incidence of death, new malignancies and significant illnesses was compared between the two groups, 5 years later.

RESULTS

Anaemic patients were less likely to be living at home at baseline. Although survival was lower for the anaemic group at all follow-up times, these differences were not significantly different. Over 5 years, there were no significant differences between groups in the types of problems that developed.

CONCLUSIONS

A mild normocytic anaemia in older people, in the absence of an obvious cause, is not associated with significant differences in outcomes but is associated with poorer independence and a trend to lower survival. We suggest it may therefore be a marker of frailty in older people.

Person-to-person transmission of Giardia lamblia in day-care nurseries

In an outbreak of giardiasis at two day-care nurseries in metropolitan Toranto Giardia lamblia appeared to be transmitted person to person. No common source of infection could be found. The proportions of children infected in the two nurseries were 39% and 17%; infection was spread to 7% and 23% of their household contacts. Of the infected children and household contacts 26% and 30% respectively of those for whom detailed information could be obtained were symptomatic. Canadian children were more likely to be infected and symptomatic than were immigrant children attending the nurseries. The most susceptible ages for infection were 1 to 3 years. The results of this study suggest that all children in day-care nurseries who are infected with G. lamblia should be treated, regardless of whether they are symptomatic.