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Most malaria morbidity in Kenya is due toPlasmodium falciparumwith no cases attributed toP.vivax. Little is known about the epidemiology in northern Kenya along the border with Ethiopia and Sudan. We found that 2% of household members ofP.falciparumcases were infected withP.vivax, affecting all ages in urban and rural sites.

A signature remains elusive of naturally-acquired immunity againstPlasmodium falciparum. We identifiedP. falciparumin a 14-month cohort of 239 people in Kenya, genotyped at immunogenic parasite targets expressed in the pre-erythrocytic (circumsporozoite protein, CSP) and blood (apical membrane antigen 1, AMA-1) stages, and classified into epitope type based on variants in the DV10, Th2R, and Th3R epitopes in CSP and the c1L region of AMA-1. Compared to asymptomatic index infections, symptomatic malaria was associated with a reduced reinfection by parasites bearing homologous CSP-Th2R (adjusted hazard ratio [aHR]:0.63; 95% CI:0.45–0.89; p=0.008) CSP-Th3R (aHR:0.71; 95% CI:0.52–0.97; p=0.033), and AMA-1 c1L (aHR:0.63; 95% CI:0.43–0.94; p=0.022) epitope types. The association of symptomatic malaria with reduced risk of homologous reinfection was strongest for rare epitope types. Symptomatic malaria more effectively promotes functional immune responses. The phenotype represents a legible molecular epidemiologic signature of naturally-acquired immunity by which to identify new antigen targets.

Human movement impacts the spread and transmission of infectious diseases. Recently, a large reservoir of Plasmodium falciparum malaria was identified in a semi-arid region of northwestern Kenya historically considered unsuitable for malaria transmission. Understanding the sources and patterns of transmission attributable to human movement would aid in designing and targeting interventions to decrease the unexpectedly high malaria burden in the region. Toward this goal, polymorphic parasite genes (ama1, csp) in residents and passengers traveling to Central Turkana were genotyped by amplicon deep sequencing. Genotyping and epidemiological data were combined to assess parasite importation. The contribution of travel to malaria transmission was estimated by modelling case reproductive numbers inclusive and exclusive of travelers. P. falciparum was detected in 6.7% (127/1891) of inbound passengers, including new haplotypes which were later detected in locally-transmitted infections. Case reproductive numbers approximated 1 and did not change when travelers were removed from transmission networks, suggesting that transmission is not fueled by travel to the region but locally endemic. Thus, malaria is not only prevalent in Central Turkana but also sustained by local transmission. As such, interrupting importation is unlikely to be an effective malaria control strategy on its own, but targeting interventions locally has the potential to drive down transmission.

Sickle-trait hemoglobin (HbAS) confers nearly complete protection from severe, life-threatening falciparum malaria in African children. Despite this clear protection, the molecular mechanisms by which HbAS confers these protective phenotypes remain incompletely understood. As a forward genetic screen for aberrant parasite transcriptional responses associated with parasite neutralization in HbAS red blood cells (RBCs), we performed comparative transcriptomic analyses of Plasmodium falciparum in normal (HbAA) and HbAS erythrocytes during both in vitro cultivation of reference parasite strains and naturally occurring P. falciparum infections in Malian children with HbAA or HbAS. During in vitro cultivation, parasites matured normally in HbAS RBCs, and the temporal expression was largely unperturbed of the highly ordered transcriptional program that underlies the parasite’s maturation throughout the intraerythrocytic development cycle (IDC). However, differential expression analysis identified hundreds of transcripts aberrantly expressed in HbAS, largely occurring late in the IDC. Surprisingly, transcripts encoding members of the Maurer’s clefts were overexpressed in HbAS despite impaired parasite protein export in these RBCs, while parasites in HbAS RBCs underexpressed transcripts associated with the endoplasmic reticulum and those encoding serine repeat antigen proteases that promote parasite egress. Analyses of P. falciparum transcriptomes from 32 children with uncomplicated malaria identified stage-specific differential expression: among infections composed of ring-stage parasites, only cyclophilin 19B was underexpressed in children with HbAS, while trophozoite-stage infections identified a range of differentially expressed transcripts, including downregulation in HbAS of several transcripts associated with severe malaria in collateral studies. Collectively, our comparative transcriptomic screen in vitro and in vivo indicates that P. falciparum adapts to HbAS by altering its protein chaperone and folding machinery, oxidative stress response, and protein export machinery. Because HbAS consistently protects from severe P. falciparum, modulation of these responses may offer avenues by which to neutralize P. falciparum parasites. IMPORTANCE Sickle-trait hemoglobin (HbAS) confers nearly complete protection from severe, life-threatening malaria, yet the molecular mechanisms that underlie HbAS protection from severe malaria remain incompletely understood. Here, we used transcriptome sequencing (RNA-seq) to measure the impact of HbAS on the blood-stage transcriptome of Plasmodium falciparum in in vitro time series experiments and in vivo samples from natural infections. Our in vitro time series data reveal that, during its blood stage, P. falciparum’s gene expression in HbAS is impacted primarily through alterations in the abundance of gene products as opposed to variations in the timing of gene expression. Collectively, our in vitro and in vivo data indicate that P. falciparum adapts to HbAS by altering its protein chaperone and folding machinery, oxidative stress response, and protein export machinery. Due to the persistent association of HbAS and protection from severe disease, these processes that are modified in HbAS may offer strategies to neutralize P. falciparum.

Sickle-trait hemoglobin (HbAS) confers near-complete protection from severe, life-threatening falciparum malaria in African children. Despite this clear protection, the molecular mechanisms by which HbAS confers these protective phenotypes remain incompletely understood. As a forward genetic screen for aberrant parasite transcriptional responses associated with parasite neutralization in HbAS red blood cells (RBCs), we performed comparative transcriptomic analyses ofPlasmodium falciparumin normal (HbAA) and HbAS erythrocytes during bothin vitrocultivation of reference parasite strains and naturally-occurringP. falciparuminfections in Malian children with HbAA or HbAS. Duringin vitrocultivation, parasites matured normally in HbAS RBCs, and the temporal expression was largely unperturbed of the highly ordered transcriptional program that underlies the parasite’s maturation throughout the intraerythrocytic development cycle (IDC). However, differential expression analysis identified hundreds of transcripts aberrantly expressed in HbAS, largely occurring late in the IDC. Surprisingly, transcripts encoding members of the Maurer’s clefts were overexpressed in HbAS despite impaired parasite protein export in these RBCs, while parasites in HbAS RBCs underexpressed transcripts associated with the endoplasmic reticulum and those encoding serine repeat antigen proteases that promote parasite egress. Analyses ofP. falciparumtranscriptomes from 32 children with uncomplicated malaria identified stage-specific differential expression: among infections composed of ring-stage parasites, only cyclophilin 19B was underexpressed in children with HbAS, while trophozoite-stage infections identified a range of differentially-expressed transcripts, including downregulation in HbAS of several transcripts associated with severe malaria in collateral studies. Collectively, our comparative transcriptomic screenin vitroandin vivoindicates thatP. falciparumadapts to HbAS by altering its protein chaperone and folding machinery, oxidative stress response, and protein export machinery. Because HbAS consistently protects from severeP. falciparum, modulation of these responses may offer avenues by which to neutralizeP. falciparumparasites.ImportanceSickle-trait hemoglobin (HbAS) confers near-complete protection from severe, life-threatening malaria, yet the molecular mechanisms that underlie HbAS protection from severe malaria remain incompletely understood. Here, we use RNA-seq to measure the impact of HbAS on the blood stage transcriptome ofPlasmodium falciparuminin vitrotime series experiments andin vivosamples from natural infections. Our in vitrotime series data reveal that, during its blood stage,P. falciparum’sgene expression in HbAS is impacted primarily through alterations in the abundance of gene products as opposed to variations in the timing of gene expression. Collectively, ourin vitroandin vivodata indicate thatP. falciparumadapts to HbAS by altering its protein chaperone and folding machinery, oxidative stress response, and protein export machinery. Due to the persistent association of HbAS and protection from severe disease, these processes that are modified in HbAS may offer strategies to neutralizeP. falciparum.

Background There is a wide ranging incidence of venous thromboembolism after surgery and it continues to be a major cause of morbidity after spinal procedures.This study’s aim was to investigate the relationship between timing and administration of venous thromboembolism (VTE) pharmacologic chemoprophylaxis after spinal surgery and the resulting VTE and bleeding complications by reviewing current practices and outcomes at a high-volume single institution to better define opportunities for perioperative intervention to prevent VTE without increasing bleeding complications. Methods All patients who underwent elective one or two-stage lumbar spinal fusion procedures were identified. A logistic regression was used to evaluate (1) risk of symptomatic VTE within 30 days of surgery and (2) bleeding-related complications. The odds of developing a VTE as well as bleeding-related complications were compared among the three treatment groups: no chemoprophylaxis, chemoprophylaxis 24h post-surgery. Results When adjusted for doses administered, the odds of developing a postoperative VTE within 30 days were 0.189 (95% confidence interval (0.044, 0.808)) in patients who received anticoagulation Conclusion Patients undergoing elective spinal surgery who received anticoagulation within 24h of the conclusion of their procedure had an 81% reduction in the odds of developing a deep vein thrombosis within 30 days with no significant difference in bleeding complications.

Background:Asymptomatic Plasmodium falciparum infections are common in sub-Saharan Africa, but their effect on subsequent symptomaticity is incompletely understood.Methods:In a 29-month cohort of 268 people in Western Kenya, we investigated the association between asymptomatic P. falciparum and subsequent symptomatic malaria with frailty Cox models.Results:Compared to being uninfected, asymptomatic infections were associated with an increased 1 month likelihood of symptomatic malaria (adjusted hazard ratio [aHR]: 2.61, 95% CI: 2.05 to 3.33), and this association was modified by sex, with females (aHR: 3.71, 95% CI: 2.62 to 5.24) at higher risk for symptomaticity than males (aHR: 1.76, 95% CI: 1.24 to 2.50). This increased symptomatic malaria risk was observed for asymptomatic infections of all densities and in people of all ages. Long-term risk was attenuated but still present in children under age 5 (29-month aHR: 1.38, 95% CI: 1.05 to 1.81).Conclusions:In this high-transmission setting, asymptomatic P. falciparum can be quickly followed by symptoms and may be targeted to reduce the incidence of symptomatic illness.Funding:This work was supported by the National Institute of Allergy and Infectious Diseases (R21AI126024 to WPO, R01AI146849 to WPO and SMT).

Background Repeated exposure to malaria infections could protect against symptomatic progression as people develop adaptive immunity to infections acquired over time. Methods We investigated how new, recurrent, and persistent Plasmodium falciparum infections were associated with the odds of developing symptomatic compared with asymptomatic malaria. Using a 14-month longitudinal cohort in Western Kenya, we used amplicon deep sequencing of 2 polymorphic genes (pfama1 and pfcsp) to assess overlap of parasite genotypes (represented by haplotypes) acquired within an individual’s successive infections. We hypothesized infections with novel haplotypes would increase the odds of symptomatic malaria. Results After excluding initial infections, we observed 534 asymptomatic and 88 symptomatic infections across 186 people. We detected 109 pfcsp haplotypes, and each infection was classified as harboring novel, recurrent, or persistent haplotypes. Incident infections with only new haplotypes had higher odds of symptomatic malaria when compared with infections with only recurrent haplotypes [odds ratio (OR): 3.24; 95% confidence interval (CI), 1.20–8.78], but infections with both new and recurrent haplotypes (OR: 0.64; 95% CI: 0.15–2.65) did not. Assessing persistent infections, those with mixed (persistent with new or recurrent) haplotypes (OR: 0.77; 95% CI: 0.21–2.75) had no association with symptomatic malaria compared with infections with only persistent haplotypes. Results were similar for pfama1. Conclusions These results confirm that incident infections with only novel haplotypes were associated with increased odds of symptomatic malaria compared with infections with only recurrent haplotypes but this relationship was not seen when haplotypes persisted over time in consecutive infections.

Malaria control may be enhanced by targeting reservoirs of Plasmodium falciparum transmission. One putative reservoir is asymptomatic malaria infections and the scale of their contribution to transmission in natural settings is not known. We assess the contribution of asymptomatic malaria to onward transmission using a 14-month longitudinal cohort of 239 participants in a high transmission site in Western Kenya. We identify P. falciparum in asymptomatically- and symptomatically-infected participants and naturally-fed mosquitoes from their households, genotype all parasites using deep sequencing of the parasite genes pfama1 and pfcsp, and use haplotypes to infer participant-to-mosquito transmission through a probabilistic model. In 1,242 infections (1,039 in people and 203 in mosquitoes), we observe 229 (pfcsp) and 348 (pfama1) unique parasite haplotypes. Using these to link human and mosquito infections, compared with symptomatic infections, asymptomatic infections more than double the odds of transmission to a mosquito among people with both infection types (Odds Ratio: 2.56; 95% Confidence Interval (CI): 1.36–4.81) and among all participants (OR 2.66; 95% CI: 2.05–3.47). Overall, 94.6% (95% CI: 93.1–95.8%) of mosquito infections likely resulted from asymptomatic infections. In high transmission areas, asymptomatic infections are the major contributor to mosquito infections and may be targeted as a component of transmission reduction., Asymptomatic malaria infections contribute to transmission. Here, Sumner et al. infer participant-to-mosquito transmission by sampling naturally-fed mosquitoes from households in Western Kenya and find that asymptomatic infections more than double the odds of transmission to a mosquito compared to symptomatic infections.

Direct detection of genetic biomarkers in tissue and body fluids without complex target extraction and amplification processes can revolutionize nucleic acid-based diagnostics by enabling the use of this technology at the point-of-care. The development of point-of-care diagnostics is important to increase access to early treatment in underserved populations in low to middle income countries, which are disproportionally affected by infectious diseases and increasingly affected by certain types of cancer. The main obstacle to the development of such technologies is the low concentration of target sequences that makes this goal challenging. We report a method for direct detection of pathogen RNA in blood lysate using a bioassay using surface-enhanced Raman spectroscopy (SERS)-based detection assay that can be integrated in a “lab-in-a-stick” portable device. We could directly detect synthetic target with a limit of detection of 200 fM and, more importantly, we detected P. falciparum malaria parasite RNA directly in infected red blood cells lysate. Additionally, this paper will discuss the use of the developed assay for the identification of head and neck squamous cell carcinoma (HNSCC), which is an increasingly prevalent malignancy in low to middle income countries.

Direct detection of genetic biomarkers in body fluid lysate without target amplification will revolutionize nucleic acid-based diagnostics. However, the low concentration of target sequences makes this goal challenging. We report a method for direct detection of pathogen RNA in blood lysate using a bioassay using surface-enhanced Raman spectroscopy (SERS)-based detection integrated in a “lab-in-a-stick” portable device. Two levels of signal enhancement were employed to achieve the sensitivity required for direct detection. Each target sequence was tagged with an ultrabright SERS-encoded nanorattle with ultrahigh SERS signals, and these tagged target sequences were concentrated into a focused spot for detection using hybridization sandwiches with magnetic microbeads. Furthermore, the washing process was automated by integration into a “lab-in-a-stick” portable device. We could directly detect synthetic target with a limit of detection of 200 fM. More importantly, we detected plasmodium falciparum malaria parasite RNA directly in infected red blood cells lysate. To our knowledge, this is the first report of SERS-based direct detection of pathogen nucleic acid in blood lysate without nucleic acid extraction or target amplification. The results show the potential of our integrated bioassay for field use and point-of-care diagnostics.

Background To assess the importance of heredity in the etiology of inflammatory breast cancer (IBC), we compared IBC patients to several carefully chosen comparison groups with respect to the prevalence of first-degree family history of breast cancer. Methods IBC cases (n = 141) were compared to non-inflammatory breast cancer cases (n = 178) ascertained through George Washington University (GWU) with respect to the prevalence of first-degree family history of breast cancer and selected environmental/lifestyle risk factors for breast cancer. Similar comparisons were conducted with subjects from three case–control studies: breast cancer cases (n = 1145) and unaffected controls (n = 1142) from the Cancer Genetic Markers of Susceptibility (CGEMS) study, breast cancer cases (n = 465) and controls (n = 9317) from the Women’s Health Initiative (WHI) study, and ovarian cancer cases (n = 260) and controls (n = 331) from a study by University of Toronto (UT). Results The frequency of first-degree breast cancer family history among IBC cases was 17.0 % compared to 24.4 % for GWU breast cancer cases, 23.9 % and 17.9 % for CGEMS breast cancer cases and controls, respectively, 16.9 % and 12.6 % for WHI breast cancer cases and controls, respectively, and 24.2 % and 11.2 % for UT ovarian cancer cases and controls, respectively. IBC cases had a significantly lower prevalence of parous women than WHI breast cancer cases (OR = 0.46, 95 % CI:0.27–0.81) and controls (OR = 0.31, 95 % CI:0.20–0.49). Oral contraceptive use was significantly higher among IBC cases compared to WHI breast cancer cases (OR = 7.77, 95 % CI:4.82–12.59) and controls (OR = 8.14, 95 % CI:5.28–12.61). IBC cases had a significantly higher frequency of regular alcohol consumption (≥1 drink per day) compared to WHI controls (OR = 1.84, 95 % CI:1.20–2.82) and UT controls (OR = 1.86, 95 % CI:1.07–3.22) and higher (statistically non-significant) prevalence (21.3 %) compared to breast cancer cases from GWU (18.2 %) and WHI (15.2 %). Conclusions The prevalence of first-degree breast cancer family history among IBC cases was lower compared to breast and ovarian cancer cases but higher than unaffected individuals. Our multiple-case inflammatory and non-inflammatory breast cancer families may reflect aggregation of common genetic and/or environmental factors predisposing to both types of breast cancer. Our findings that oral contraceptive use and regular alcohol consumption may be associated with IBC warrant further investigations.

The purpose of this study was to determine whether the use of pictorial anchors improved a visual analog scale (VAS) designed to assess asthma episodes. The sample consisted of 77 children with moderate to severe asthma attending a summer camp. They rated one of two VASs, either nonpictorial (39 subjects in year 1) or pictorial (38 subjects in year 2), three times a day for 2 weeks to report the severity of their asthma symptoms. Immediately after the subjects rated the VAS, pulmonary function testing was obtained. The mean VAS scores increased 64% using the pictorial VAS while the mean PEFRs in the 2 years were almost identical, suggesting that changes on the VAS were not due to differences in pulmonary functioning. For boys, the increase in individual mean VAS score in year 2 using the pictorial VAS was 44%; for girls, the increase in individual mean VAS scores was 112%. Use of a pictorial VAS increases the range of severity of symptoms reported by children with asthma. The instrument may be a useful tool in the systematic quantifiable assessment of subjective symptomatology in pediatric asthma.