"Linkage to care" among people living with HIV - definition in the era of "universal test and treat" in a sub-Sahara African setting

BACKGROUND: Prompt linkage to human immunodeficiency virus (HIV) care after diagnosis is of utmost importance for individual health and reduction of HIV transmission. Different definitions for "linkage to care" have challenged comparisons as a public health marker. Its meaning in the era of "universal test and treat" has transformed in all settings, but is most relevant in sub-Sahara Africa, where the burden of new HIV infection is still highest. METHODS: For this narrative review on "linkage to care" definitions with a focus on sub-Saharan Africa, we searched PubMed/Medline between September and December 2020, restricted to the period 2000-2020 using Boolean operators: "HIV" AND ("linkage to care" OR "engagement in care") and screened for institutional definitions of "linkage to care". Additionally, as one example of a rural sub-Saharan African setting, we analysed linkage steps within the Chronic Diseases Clinic Ifakara (CDCI) and its associated Kilombero and Ulanga Antiretroviral Cohort (KIULARCO) in rural Tanzania between 1 January 2017 and 31 March 2019. RESULTS: We analysed 81 articles that included "linkage to care" within different study settings and HIV organisations. Major differences in defining "linkage to care" exist, according to setting and location, patient populations and the timing of steps within the linkage process. We identified 16 different numerators and 10 denominators used to define linkage with time periods ranging from "same day as diagnosis" up to 12 months after diagnosis among 34 original articles from sub-Saharan Africa. At the CDCI, 1149/1671 (69%) newly diagnosed individuals were enrolled into care after diagnosis. Three months after enrolment into care, 94%, 86%, 85% and 71% of enrolled patients had a laboratory evaluation, a clinical evaluation, were initiated on treatment and had a first clinical follow-up visit after initiation of treatment, respectively. DUSCUSSION: To address the inconsistency in defining "linkage to care" and in order to guarantee the comparability of "linkage to care" in the sub-Saharan Africa region, we support the definition from the European region with some adaptions. We suggest a priority list of care indicators if more than one care indicator is available for successful "linkage to care" in the era of "universal test and treat" for sub-Sahara Africa

Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction

In the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphid Metopeurum fuscoviride, a specialist on tansy Tanacetum vulgare, and its specialist primary hymenopterous parasitoid Lysiphlebus hirticornis, both of which are characterized by multivoltine life histories and a classic metapopulation structure. Samples of the aphid host and the parasitoid were collected from eight sites in and around Jena, Germany, where both insect species co-occur, and then were genotyped using suites of polymorphic microsatellite markers. The host aphid was greatly differentiated in terms of its spatial population genetic patterning, while the parasitoid was, in comparison, only moderately differentiated. There was a positive Mantel test correlation between pairwise shared allele distance (DAS) of the host and parasitoid, i.e. if host subpopulation samples were more similar between two particular sites, so were the parasitoid subpopulation samples. We argue that while the differences in the levels of genetic differentiation are due to the differences in the biology of the species, the correlations between host and parasitoid are indicative of dependence of the parasitoid population structure on that of its aphid host. The parasitoid is genetically tracking behind the aphid host, as can be expected in a classic metapopulation structure where host persistence depends on a delay between host and parasitoid colonization of the patch. The results may also have relevance to the Red Queen hypothesis, whereupon in the ‘arms race’ between parasitoid and its host, the latter ‘attempts’ to evolve away from the former

Process Combination of VPP-LED and Vacuum Die Casting for Producing Complex Ceramic 3D-MID

Future developments lead to increasing demands on mechatronic integrated devices (MID). Therefore, ceramics have to be used as substrate material and conductor tracks have to be located in the interior of components to be sufficiently protected. A process combination of vat photopolymerization (VPP-LED) and vacuum die casting is investigated for realizing such structures. First, optimized process parameters are derived by studying the filling behavior of straight capillaries. Subsequently, the results are transferred to complex additively manufactured substrates to derive design guidelines

Anisotropic a posteriori error estimate for the virtual element method

We derive an anisotropic a posteriori error estimate for the adaptive conforming virtual element approximation of a paradigmatic two-dimensional elliptic problem. In particular, we introduce a quasi-interpolant operator and exploit its approximation results to prove the reliability of the error indicator. We design and implement the corresponding adaptive polygonal anisotropic algorithm. Several numerical tests assess the superiority of the proposed algorithm in comparison with standard polygonal isotropic mesh refinement schemes

Outpacing movement — ultrafast volume coverage in neuropediatric magnetic resonance imaging

Background Conventional MRI sequences are often affected in neuropediatric imaging by unavoidable movements. Therefore, children younger than 6 years usually have to be examined under sedation/anesthesia. A new real-time MRI technique with automatic slice advancement allows for motion-robust T2-weighted volume coverage of the whole brain within a few seconds in adults. Objective To evaluate to which extent the new volume coverage method can be used to visualize cerebrospinal fluid and reduce the need for anesthesia in children. Materials and methods We assessed 30 children ages 6 years and younger with suspected or proven hydrocephalus, hygroma or macrocephalus using volume coverage sequences with 20 slices per second in three planes. If necessary, a parent was placed in the bore together with the child for calming and gentle immobilization. We compared visualization of cerebrospinal fluid spaces and course of the shunt catheter in volume coverage sequences vs. fast spin-echo sequences. Results The clinical issue could be sufficiently assessed in all children with use of volume coverage sequences, whereas conventional fast spin-echo sequences performed moderately to poorly. Visualization of the tip of a shunt failed in 16% of volume coverage scans and 27% of turbo spin-echo scans. A subsequent examination under anesthesia was never necessary. None of the examinations had to be stopped prematurely. Conclusion The motion-robust volume coverage sequences with T2-type contrast can be used to avoid sedation of children in the evaluation of cerebrospinal fluid spaces, even in the presence of vigorous motion. For other indications and contrasts, the technique must still be evaluated

Composition analysis of liquid particles in the Arctic stratosphere under synoptic conditions

International audienceSynoptic scale polar stratospheric clouds (PSCs) that formed without the presence of mountain lee waves were observed in early December 2002 from Kiruna/Sweden using balloon-borne instruments. The physical, chemical, and optical properties of the particles were measured. Within the PSC solid particles existed whenever the temperature was below the equilibrium temperature for nitric acid trihydrate and liquid particles appeared when the temperature fell below an even lower threshold about 3 K above the frost point with solid particles still present. The correlation of liquid supercooled ternary solution aerosols with local temperatures is a pronounced feature observed during this flight; average molar ratios H2O/HNO3 were somewhat higher than predicted by models. In addition HCl has been measured for the first time in liquid aerosols. The chlorine isotope signature served as a unique tool to identify unambiguously HCl dissolved in STS particles. Within a narrow temperature range of about three degrees above the frost point, the measured average amount of HCl in liquid particles is below 1 weight%

Composition analysis of liquid particles in the Arctic stratosphere

International audienceSynoptic scale polar stratospheric clouds (PSCs) that formed without the presence of mountain leewaves were observed in early December 2002 from Kiruna/Sweden using balloon-borne instruments. The physical, chemical, and optical properties of the particles were measured. Within the PSC solid particles existed whenever the temperature was below the equilibrium temperature for nitric acid trihydrate and liquid particles appeared when the temperature fell below an even lower threshold about 3 K above the frost point. The correlation of liquid supercooled ternary solution aerosols with local temperatures is a pronounced feature observed during this flight although the molar ratios H2O/HNO3 were about a factor of 2 higher than model predictions. In addition HCl has been measured for the first time in liquid aerosols. The chlorine isotope signature served as a unique tool to identify unambiguously HCl dissolved in STS particles. Within a narrow temperature range of about three degrees above the frost point, measured HCl molar ratios are below 1 weight%. There is only fair agreement with model predictions