Clarifying Bunyamwera virus riddles of the past

Pyrosequencing data and phylogenetic analysis for the full genome of Ilesha virus, Ngari virus and Calovo virus are described clarifying their much discussed relationship within the species Bunyamwera virus of the genus Orthobunyavirus of the Bunyaviridae.     

Suicide mortality gap between Francophones and Anglophones of Quebec, Canada

Purpose

Few studies evaluate language-group differences in suicide mortality. This study assessed the suicide mortality gap between Francophones and Anglophones of Quebec, Canada according to age, sex, method, region and socioeconomic deprivation.

Methods

Suicide decedents were extracted from the Quebec death file for 1989–2007 (N = 24,465). Age- and sex-specific suicide mortality rates were calculated for four periods (1989–1993, 1994–1998, 1999–2003, 2004–2007) for Francophones and Anglophones aged ≥10 years. Age-standardized rates of suicide by method, region, and level of social and material deprivation were calculated for each sex. Rate ratios and rate differences were estimated.

Results

Suicide rates for Francophones were two to three times higher than rates for Anglophones, and differences were greatest for adults aged 25–64 years. Francophone males had more than two times the rate of suicide by hanging or firearms than Anglophone males. Francophone females had twice the rate of hanging, poisoning or firearm suicide as Anglophone females, although precision was low. Francophone-Anglophone suicide mortality gaps were higher in urban areas despite lower suicide rates, and varied little across levels of social and material deprivation.

Conclusions

There was a large suicide mortality gap between Francophones and Anglophones of Quebec; especially, among adults aged 25–64 years.     

Reproductive success in Anopheles arabiensis and the M and S molecular forms of Anopheles gambiae: Do natural sporozoite infection and body size matter?

Malaria parasites stages prior to sporozoite formation are known to affect the fecundity of several species of mosquitoes in the laboratory, but little is known about this phenomenon in natural conditions especially with sporozoite-infected anophelines. The reproductive success of wild-caught Anopheles arabiensis and the M and S molecular forms of Anopheles gambiae was investigated by comparing females infected with Plasmodium falciparum sporozoites to females free of sporozoites. Association between sporozoite-infected females' body size and their egg batch size was also measured. There was no significant reduction in egg production due to sporozoite infection among wild females An. arabiensis and the M and S form of An. gambiae. The infected groups and the controls laid similar numbers of eggs. A positive association was found between body size of females infected with P. falciparum and mean egg production. Infected females of the molecular forms of An. gambiae and their sibling species An. arabiensis invest similarly in egg batch size regardless of their body size although the expected egg batch size may differ among them because of differences in their mean body size. A reduction of egg production related to infection status was not observed among females harboring sporozoites. Therefore for the gonotrophic cycles that occur once sporozoites are present, natural infection of all three vectors we studied has no or minimal effect on their densities or their reproductive outputs.     

Life expectancy gap between the Francophone majority and Anglophone minority of a Canadian population

Language is an important determinant of health, but analyses of linguistic inequalities in mortality are scant, especially for Canadian linguistic groups with European roots. We evaluated the life expectancy gap between the Francophone majority and Anglophone minority of Québec, Canada, both over time and across major provincial areas. Arriaga’s method was used to estimate the age and cause of death groups contributing to changes in the life expectancy gap at birth between 1989–1993 and 2002–2006, and to evaluate patterns across major provincial areas (metropolitan Montréal, other metropolitan centres, and small cities/rural areas). Life expectancy at birth was greater for Anglophones, but the gap decreased over time by 1.3 years (52% decline) in men and 0.9 years (47% decline) in women, due to relatively sharper reductions in Francophone mortality from several causes, except lung cancer which countered reductions in women. The life expectancy gap in 2002–2006 was widest in other metropolitan centres (men 5.1 years, women 3.2 years), narrowest in small cities/rural areas (men 0.8 years, women 0.7 years), and tobacco-related causes were the main contributors. Only young Anglophones <40 years in small cities/rural areas had mortality higher than Francophones, resulting in a narrower gap in these areas. Differentials in life expectancy favouring Anglophones decreased over time, but varied across areas of Québec. Tobacco-related causes accounted for the majority of the current life expectancy gap.     

Biological Characteristics and Patterns of Codon Usage Evolution for the African Genotype Zika Virus

We investigated temporal trends of codon usage changes for different host species to determine their importance in Zika virus (ZIKV) evolution. Viral spillover resulting from the potential of codon adaptation to host genome was also assessed for the African genotype ZIKV in comparison to the Asian genotype. To improve our understanding on its zoonotic maintenance, we evaluated in vitro the biological properties of the African genotype ZIKV in vertebrate and mosquito cell lines. Analyses were performed in comparison to Yellow fever virus (YFV). Despite significantly lower codon adaptation index trends than YFV, ZIKV showed evident codon adaptation to vertebrate hosts, particularly for the green African monkey Chlorocebus aethiops. PCA and CAI analyses at the individual ZIKV gene level for both human and Aedes aegypti indicated a clear distinction between the two genotypes. African ZIKV isolates showed higher virulence in mosquito cells than in vertebrate cells. Their higher replication in mosquito cells than African YFV confirmed the role of mosquitoes in the natural maintenance of the African genotype ZIKV. An analysis of individual strain growth characteristics indicated that the widely used reference strain MR766 replicates poorly in comparison to African ZIKV isolates. The recombinant African Zika virus strain ArD128000*^E/NS5 may be a good model to include in studies on the mechanism of host tropism, as it cannot replicate in the tested vertebrate cell line.