Molecular evidence of Plasmodium vivax infection in Duffy negative symptomatic individuals from Dschang, West Cameroon

Background: Plasmodium vivax infection is known to be rare in West/Central Africa, the most accepted explanation being the lack of expression of erythroid Duffy antigen in the local human populations. Duffy negativity prevents the parasite to exploit the entry mechanism on the red blood cell surface. However, there are a growing number of reported vivax infections in Duffy-negative individuals. Data on P. vivax circulation in Cameroon are limited. The aim of the study was to evaluate the P. vivax presence, and its association with the Duffy genotype in West Cameroon. Results: Overall, 484 blood samples were collected consecutively from febrile outpatients attending the Dschang’s Hospital (West Cameroon) during a 3-months period. Plasmodium vivax infection was detected by PCR in 5.6% (n = 27/484) of the cases, representing 38.6% (n = 27/70) of all Plasmodium infections detected. All P. vivax infected individuals showed a Duffy-negative genotype, and the frequency of Duffy-positive individuals in the whole tested population was 1.7%. Conclusions: The results of this study confirm the circulation of P. vivax in Cameroon, as well as that the lack of expression of Duffy-antigen does not confer full protection against vivax malaria acquisition

Frequent expansion of Plasmodium vivax Duffy Binding Protein in Ethiopia and its epidemiological significance.

Plasmodium vivax invasion of human erythrocytes depends on the Duffy Binding Protein (PvDBP) which interacts with the Duffy antigen. PvDBP copy number has been recently shown to vary between P. vivax isolates in Sub-Saharan Africa. However, the extent of PvDBP copy number variation, the type of PvDBP multiplications, as well as its significance across broad samples are still unclear. We determined the prevalence and type of PvDBP duplications, as well as PvDBP copy number variation among 178 Ethiopian P. vivax isolates using a PCR-based diagnostic method, a novel quantitative real-time PCR assay and whole genome sequencing. For the 145 symptomatic samples, PvDBP duplications were detected in 95 isolates, of which 81 had the Cambodian and 14 Malagasy-type PvDBP duplications. PvDBP varied from 1 to >4 copies. Isolates with multiple PvDBP copies were found to be higher in symptomatic than asymptomatic infections. For the 33 asymptomatic samples, PvDBP was detected with two copies in two of the isolates, and both were the Cambodian-type PvDBP duplication. PvDBP copy number in Duffy-negative heterozygotes was not significantly different from that in Duffy-positives, providing no support for the hypothesis that increased copy number is a specific association with Duffy-negativity, although the number of Duffy-negatives was small and further sampling is required to test this association thoroughly

The Intersection of Art and Public History: Schmucker Art Gallery’s Newest Exhibit

“‘Pray For the People Who Feed You’: Voices of Pauper Children in the Industrial Age” is the newest exhibit to be featured in the Schmucker Art Gallery at Gettysburg College. The exhibit was curated by Gettysburg College senior Rebecca Duffy ’16, and is the culmination of her three semester International Bridge Course (IBC) program. At its opening on Friday, October 2, Duffy discussed her experiences with the IBC program and the process she went through in putting together this unique project [excerpt]

Letter to Governor Langer regarding Foreclosure Moratorium, 1933

September 12, 1933, letter from Clyde Duffy of the Sinness and Duffy law firm in Devils Lake to Governor William Langer regarding the moratorium on farm foreclosures in North Dakota. Duffy wrote to Langer asking to be allowed to foreclose on a farm in Rock Lake.https://commons.und.edu/langer-papers/1016/thumbnail.jp

Biochemical, biophysical, and functional characterization of bacterially expressed and refolded receptor binding domain of Plasmodium vivax duffy-binding

Invasion of erythrocytes by malaria parasites is mediated by specific molecular interactions. Plasmodium vivax is completely dependent on interaction with the Duffy blood group antigen to invade human erythrocytes. The P. vivax Duffy-binding protein, which binds the Duffy antigen during invasion, belongs to a family of erythrocyte-binding proteins that also includesPlasmodium falciparum sialic acid binding protein andPlasmodium knowlesi Duffy binding protein. The receptor binding domains of these proteins lie in a conserved, N-terminal, cysteine-rich region, region II, found in each of these proteins. Here, we have expressed P. vivax region II (PvRII), the P. vivax Duffy binding domain, in Escherichia coli. Recombinant PvRII is incorrectly folded and accumulates in inclusion bodies. We have developed methods to refold and purify recombinant PvRII in its functional conformation. Biochemical, biophysical, and functional characterization confirms that recombinant PvRII is pure, homogeneous, and functionally active in that it binds Duffy-positive human erythrocytes with specificity. Refolded PvRII is highly immunogenic and elicits high titer antibodies that can inhibit binding of P. vivax Duffy-binding protein to erythrocytes, providing support for its development as a vaccine candidate forP. vivax malaria. Development of methods to produce functionally active recombinant PvRII is an important step for structural studies as well as vaccine development

Reduced Plasmodium vivax Erythrocyte Infection in PNG Duffy-Negative Heterozygotes

BACKGROUND: Erythrocyte Duffy blood group negativity reaches fixation in African populations where Plasmodium vivax (Pv) is uncommon. While it is known that Duffy-negative individuals are highly resistant to Pv erythrocyte infection, little is known regarding Pv susceptibility among heterozygous carriers of a Duffy-negative allele (+/−). Our limited knowledge of the selective advantages or disadvantages associated with this genotype constrains our understanding of the effect that interventions against Pv may have on the health of people living in malaria-endemic regions. METHODS AND FINDINGS: We conducted cross-sectional malaria prevalence surveys in Papua New Guinea (PNG), where we have previously identified a new Duffy-negative allele among individuals living in a region endemic for all four human malaria parasite species. We evaluated infection status by conventional blood smear light microscopy and semi-quantitative PCR-based strategies. Analysis of a longitudinal cohort constructed from our surveys showed that Duffy heterozygous (+/−) individuals were protected from Pv erythrocyte infection compared to those homozygous for wild-type alleles (+/+) (log-rank tests: LM, p = 0.049; PCR, p = 0.065). Evaluation of Pv parasitemia, determined by semi-quantitative PCR-based methods, was significantly lower in Duffy +/− vs. +/+ individuals (Mann-Whitney U: p = 0.023). Overall, we observed no association between susceptibility to P. falciparum erythrocyte infection and Duffy genotype. CONCLUSIONS: Our findings provide the first evidence that Duffy-negative heterozygosity reduces erythrocyte susceptibility to Pv infection. As this reduction was not associated with greater susceptibility to Pf malaria, our in vivo observations provide evidence that Pv-targeted control measures can be developed safely

Lesbian Love Sonnets: Adrienne Rich and Carol Ann Duffy

Our conceptualization of sexuality is rooted in gender. Modern, western society defines sexuality as which genders one is and is not attracted to—often appearing as a binary between homosexuality and heterosexuality. Recently, however, queer theorists have begun to push against the idea of binary sexuality altogether. The interplay between gender and sexuality additionally manifests in the history of literature. Because the two are so intimately intertwined, writing about sexuality necessitates writing about gender. Twenty-One Love Poems by Adrienne Rich and Rapture by Carol Ann Duffy are two poetry collections where, as lesbian poets, gender and sexuality play an important role. Both Twenty-One Love Poems and Rapture draw on the tradition of sonnet sequences, a tradition defined by strict structure and gendered power dynamics. As lesbians with female speaker-poets writing about other women, Rich and Duffy both include and subvert themes and tropes, highlighted by their playing with the prescribed structure. Viewing the collections through the lens of sonnet sequences provides an intriguing perspective for examining the depiction of gender and, by extension, sexuality

Poverty, Poaching and Trafficking: What are the links?

A rapid review of academic and grey literature revealed that the links between poverty, poaching and trafficking are under-researched and poorly understood. Yet, the assumption that poaching occurs because of poverty is omnipresent, with little ‘hard evidence’ to support the claim. Despite this, the authors are confident that the links are there, based on the evidence gathered. However, their understandings are hampered by a series of factors: trafficking and poaching are overwhelmingly framed as an issue of conservation/biodiversity loss rather than of poverty and development; it is difficult to collect clear and detailed data on poaching precisely because of its illicit nature; and many of the cases examined are also linked in with conflict zones, making research even more challenging