Cardinium symbiosis as a potential confounder of mtDNA based phylogeographic inference in Culicoides imicola (Diptera: Ceratopogonidae), a vector of veterinary viruses

BACKGROUND: Culicoides imicola (Diptera: Ceratopogonidae) is an important Afrotropical and Palearctic vector of disease, transmitting viruses of animal health and economic signifcance including African horse sickness and bluetongue viruses. Maternally inherited symbiotic bacteria (endosymbionts) of arthropods can alter the frequency of COI (cytochrome c oxidase subunit I) mitochondrial haplotypes (mitotypes) in a population, masking the true patterns of host movement and gene fow. Thus, this study aimed to assess the mtDNA structure of C. imicola in relation to infection with Candidatus Cardinum hertigii (Bacteroides), a common endosymbiont of Culicoides spp. METHODS: Using haplotype network analysis, COI Sanger sequences from Cardinium-infected and -uninfected C. imicola individuals were frst compared in a population from South Africa. The network was then extended to include mitotypes from a geographic range where Cardinium infection has previously been investigated. RESULTS: The mitotype network of the South African population demonstrated the presence of two broad mitotype groups. All Cardinium-infected specimens fell into one group (Fisher’s exact test, P=0.00071) demonstrating a linkage disequilibrium between endosymbiont and mitochondria. Furthermore, by extending this haplotype network to include other C. imicola populations from the Mediterranean basin, we revealed mitotype variation between the Eastern and Western Mediterranean basins (EMB and WMB) mirrored Cardinium-infection heterogeneity. CONCLUSIONS: These observations suggest that the linkage disequilibrium of Cardinium and mitochondria refects endosymbiont gene fow within the Mediterranean basin but may not assist in elucidating host gene fow. Subsequently, we urge caution on the single usage of the COI marker to determine population structure and movement in C. imicola and instead suggest the complementary utilisation of additional molecular markers.A BBSRC Doctoral Training Partnership studentship and a Marie Curie Individual Fellowship.https://parasitesandvectors.biomedcentral.compm2022Veterinary Tropical Disease

Variation in Number and Formation of Repeat Sequences in the rDNA ITS2 Region of Five Sibling Species in the Anopheles barbirostris Complex in Thailand

Repeat sequences of approximately 100 base pairs in length were found in the rDNA ITS2 region of Anopheles barbirostris van der Wulp (Diptera: Culicidae) species A1, A2, A3, A4, and An. campestris-like in the An. barbirostris complex. Variation in the number of repeats was observed among the five sibling species. Specifically, 10 repeats were observed in A1, eight in A2, A4, and campestris-like, and three in A3. Based on similarities in the sequences of the repeats, related repeats were classified into nine groups. Although A2, A4, and the campestris-like species had the same number of repeats, the ITS2 region of the three species contained different groups of repeats. Excluding the repeat sequences facilitated good alignment of the ITS2 region in the five sibling species. Phylogenetic analyses of the 95 isolines were compared with results obtained from mitochondrial genes (COI and COII). The results revealed marked differences among the five sibling species, particularly regarding the ITS2 region of A3, which was more distinct from the other four species than COI and COIL Repeat sequences in the ITS2 region of other Anopheles species retrieved from GenBank also were analyzed. New repeat sequences were found in An. beklemishevi Stegnii and Kabanova, An. crucians Wiedemann and An. funestus Giles, suggesting that the occurrence of repeat sequences in the ITS2 region are not rare in anopheline mosquitoes

Withdrawal of life-support in paediatric intensive care - a study of time intervals between discussion, decision and death

<p>Abstract</p> <p>Background</p> <p>Scant information exists about the time-course of events during withdrawal of life-sustaining treatment. We investigated the time required for end-of-life decisions, subsequent withdrawal of life-sustaining treatment and the time to death.</p> <p>Methods</p> <p>Prospective, observational study in the ICU of a tertiary paediatric hospital.</p> <p>Results</p> <p>Data on 38 cases of withdrawal of life-sustaining treatment were recorded over a 12-month period (75% of PICU deaths). The time from the first discussion between medical staff and parents of the subject of withdrawal of life-sustaining treatment to parents and medical staff making the decision varied widely from immediate to 457 hours (19 days) with a median time of 67.8 hours (2.8 days). Large variations were subsequently also observed from the time of decision to actual commencement of the process ranging from 30 minutes to 47.3 hrs (2 days) with a median requirement of 4.7 hours. Death was apparent to staff at a median time of 10 minutes following withdrawal of life support varying from immediate to a maximum of 6.4 hours. Twenty-one per cent of children died more than 1 hour after withdrawal of treatment. Medical confirmation of death occurred at 0 to 35 minutes thereafter with the physician having left the bedside during withdrawal in 18 cases (48%) to attend other patients or to allow privacy for the family.</p> <p>Conclusions</p> <p>Wide case-by-case variation in timeframes occurs at every step of the process of withdrawal of life-sustaining treatment until death. This knowledge may facilitate medical management, clinical leadership, guidance of parents and inform organ procurement after cardiac death.</p

The tree that hides the forest: Cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus Complex (Diptera: Ceratopogonidae) at the European level

Background: Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex. Methods: Portion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex. Results: Our analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus. Conclusions: To our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region.[Figure not available: See fulltext.

Mortality in very long-stay pediatric intensive care unit patients and incidence of withdrawal of treatment

Background: The mortality for children with prolonged stay in pediatric intensive care units (PICU) is much higher than overall mortality. The incidence of withdrawal or limitation of therapy in this group is unknown. Purpose: To assess mortality and characteristics of children admitted for ≥28 days to our ICU, and to describe the extent to which limitations of care were involved in the terminal phase preceding death. Methods: For the period 2003 to 2005 clinical data were collected retrospectively for children with prolonged stay (defined as ≥28 days) in a medical/surgical PICU of a university children's hospital. Results: In the PICU, 4.4% of the children (116/2,607, equal gender, mean age 29 days) had a prolonged stay. Median (range) stay was 56 (28-546) days. These children accounted for 3% of total admissions and occupied 63% of total admission days. Mortality during admission for this group was fiv