Changing Geographic Patterns and Risk Factors for Avian Influenza A(H7N9) Infections in Humans, China.

The fifth epidemic wave of avian influenza A(H7N9) virus in China during 2016-2017 demonstrated a geographic range expansion and caused more human cases than any previous wave. The factors that may explain the recent range expansion and surge in incidence remain unknown. We investigated the effect of anthropogenic, poultry, and wetland variables on all epidemic waves. Poultry predictor variables became much more important in the last 2 epidemic waves than they were previously, supporting the assumption of much wider H7N9 transmission in the chicken reservoir. We show that the future range expansion of H7N9 to northern China may increase the risk of H7N9 epidemic peaks coinciding in time and space with those of seasonal influenza, leading to a higher risk of reassortments than before, although the risk is still low so far.

Progress in coverage of bed net ownership and use in Burkina Faso 2003-2014: evidence from population-based surveys.

BACKGROUND: Use of insecticide-treated bed nets (ITNs) is the cornerstone of malaria prevention. In 2010 and 2013, the Burkina Faso Government launched mass distribution campaigns of ITNs to increase coverage of ownership and use in the country. This study assessed the progress towards universal bed net coverage in Burkina Faso. METHODS: The authors used data from the Burkina Faso 2003 and 2010 Demographic and Health Surveys (DHS), the 2006 Multiple Indicator Cluster Surveys (MICS) and the 2014 Malaria Indicator Survey (MIS). For each survey, the authors computed key malaria prevention indicators in line with recommendations from the Survey and Indicator Task Force of the Roll Back Malaria Monitoring and Evaluation Reference Group. The trends over a decade was assessed by calculating percentage point change between 2003 and 2014. RESULTS: At national level, the proportion of households owning at least one ITN increased substantially from 5.6, 95% CI (4.7, 6.5%) in 2003 to 89.9% (88.5, 91.2%) in 2014, with low heterogeneity between regions. The proportion of households owning at least one ITN per two people increased significantly from 1.8% (1.4, 2.3%) in 2003 to 49.2% (47.3, 51.0%) in 2014. ITN use in the general population increased from 2.0% (1.6, 2.3%) in 2003, to 67.0% (65.3, 68.7%) in 2014. A similar trend was observed among children under the age of  five years, increasing from 1.9% (1.5, 2.4%) in 2003 to 75.2% (73.2, 77.3%) in 2014, and among pregnant women, increasing from 3.0% (1.9, 4.2%) in 2003 to 77.1% (72.9, 81.3%) in 2014. The intra-household ownership gap was 67.0% (61.5, 72.4%) in 2003, but decreased significantly to 45.3% (43.6, 47.1%) in 2014. The behavioural gap, which was relatively low in 2013 with only 20.0% of people who had access to an ITN but were not using it, further decreased to 5.9% in 2014. CONCLUSION: Burkina Faso made considerable progress in coverage of ITN ownership, access and use between 2003 and 2014, as a result of the two free mass distribution campaigns in 2010 and 2013. However, ITN coverage remains below the national targets of 100% for ownership and 80% for use. The results of 90% of ownership and 67% of use confirm that free mass distribution campaigns of ITNs are effective; however, there is room for improvement to reach and maintain optimal coverage of ITN ownership and use.

Team swimming in ant spermatozoa.

In species where females mate promiscuously, competition between ejaculates from different males to fertilize the ova is an important selective force shaping many aspects of male reproductive traits, such as sperm number, sperm length and sperm-sperm interactions. In eusocial Hymenoptera (bees, wasps and ants), males die shortly after mating and their reproductive success is ultimately limited by the amount of sperm stored in the queen's spermatheca. Multiple mating by queens is expected to impose intense selective pressure on males to optimize the transfer of sperm to the storage organ. Here, we report a remarkable case of cooperation between spermatozoa in the desert ant Cataglyphis savignyi. Males ejaculate bundles of 50-100 spermatozoa. Sperm bundles swim on average 51% faster than solitary sperm cells. Team swimming is expected to increase the amount of sperm stored in the queen spermatheca and, ultimately, enhance male posthumous fitness.

Sib mating without inbreeding in the longhorn crazy ant.

Sib matings increase homozygosity and, hence, the frequency of detrimental phenotypes caused by recessive deleterious alleles. However, many species have evolved adaptations that prevent the genetic costs associated with inbreeding. We discovered that the highly invasive longhorn crazy ant, Paratrechina longicornis, has evolved an unusual mode of reproduction whereby sib mating does not result in inbreeding. A population genetic study of P. longicornis revealed dramatic differences in allele frequencies between queens, males and workers. Mother-offspring analyses demonstrated that these allele frequency differences resulted from the fact that the three castes were all produced through different means. Workers developed through normal sexual reproduction between queens and males. However, queens were produced clonally and, thus, were genetically identical to their mothers. In contrast, males never inherited maternal alleles and were genetically identical to their fathers. The outcome of this system is that genetic inbreeding is impossible because queen and male genomes remain completely separate. Moreover, the sexually produced worker offspring retain the same genotype, combining alleles from both the maternal and paternal lineage over generations. Thus, queens may mate with their brothers in the parental nest, yet their offspring are no more homozygous than if the queen mated with a male randomly chosen from the population. The complete segregation of the male and female gene pools allows the queens to circumvent the costs associated with inbreeding and therefore may act as an important pre-adaptation for the crazy ant's tremendous invasive success.

Malaria risk assessment and mapping using satellite imagery and boosted regression trees in the Peruvian Amazon.

This is the first study to assess the risk of co-endemic Plasmodium vivax and Plasmodium falciparum transmission in the Peruvian Amazon using boosted regression tree (BRT) models based on social and environmental predictors derived from satellite imagery and data. Yearly cross-validated BRT models were created to discriminate high-risk (annual parasite index API > 10 cases/1000 people) and very-high-risk for malaria (API > 50 cases/1000 people) in 2766 georeferenced villages of Loreto department, between 2010-2017 as other parts in the article (graphs, tables, and texts). Predictors were cumulative annual rainfall, forest coverage, annual forest loss, annual mean land surface temperature, normalized difference vegetation index (NDVI), normalized difference water index (NDWI), shortest distance to rivers, time to populated villages, and population density. BRT models built with predictor data of a given year efficiently discriminated the malaria risk for that year in villages (area under the ROC curve (AUC) > 0.80), and most models also effectively predicted malaria risk in the following year. Cumulative rainfall, population density and time to populated villages were consistently the top three predictors for both P. vivax and P. falciparum incidence. Maps created using the BRT models characterize the spatial distribution of the malaria incidence in Loreto and should contribute to malaria-related decision making in the area.

Permanent genetic resources added to Molecular Ecology Resources Database 1 August 2010-30 September 2010.

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis × Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

Conditional use of sex and parthenogenesis for worker and queen production in ants.

The near-ubiquity of sexual reproduction in animal species has long been considered a paradox because sexually reproducing individuals transmit only half of their genome to their progeny. Here, we show that the ant Cataglyphis cursor circumvents this cost by using alternative modes of reproduction for the production of reproductive and nonreproductive offspring. New queens are almost exclusively produced by parthenogenesis, whereas workers are produced by normal sexual reproduction. By selectively using sex for somatic growth and parthenogenesis for germline production, C. cursor has taken advantage of the ant caste system to benefit from the advantages of both sexual and asexual reproduction.