Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

BACKGROUND : Theileria parva causes East Coast fever (ECF), one of the most economically important tick-borne diseases of cattle in sub-Saharan Africa. A live immunisation approach using the infection and treatment method (ITM) provides a strong long-term strain-restricted immunity. However, it typically induces a tick-transmissible carrier state in cattle and may lead to spread of antigenically distinct parasites. Thus, understanding the genetic composition of T. parva is needed prior to the use of the ITM vaccine in new areas. This study examined the sequence diversity and the evolutionary and biogeographical dynamics of T. parva within the African Great Lakes region to better understand the epidemiology of ECF and to assure vaccine safety. Genetic analyses were performed using sequences of two antigencoding genes, Tp1 and Tp2, generated among 119 T. parva samples collected from cattle in four agro-ecological zones of DRC and Burundi. RESULTS : The results provided evidence of nucleotide and amino acid polymorphisms in both antigens, resulting in 11 and 10 distinct nucleotide alleles, that predicted 6 and 9 protein variants in Tp1 and Tp2, respectively. Theileria parva samples showed high variation within populations and a moderate biogeographical sub-structuring due to the widespread major genotypes. The diversity was greater in samples from lowlands and midlands areas compared to those from highlands and other African countries. The evolutionary dynamics modelling revealed a signal of selective evolution which was not preferentially detected within the epitope-coding regions, suggesting that the observed polymorphism could be more related to gene flow rather than recent host immune-based selection. Most alleles isolated in the Great Lakes region were closely related to the components of the trivalent Muguga vaccine. CONCLUSIONS : Our findings suggest that the extensive sequence diversity of T. parva and its biogeographical distribution mainly depend on host migration and agro-ecological conditions driving tick population dynamics. Such patterns are likely to contribute to the epidemic and unstable endemic situations of ECF in the region. However, the fact that ubiquitous alleles are genetically similar to the components of the Muguga vaccine together with the limited geographical clustering may justify testing the existing trivalent vaccine for cross-immunity in the region.Additional file 1: Table S1. Cattle blood sample distribution across agroecological zones.Additional file 2: Table S2. Nucleotide and amino acid sequences of Tp1 and Tp2 antigen epitopes from T. parva Muguga reference sequence.Additional file 3: Table S3. Characteristics of 119 T. parva samples obtained from cattle in different agro-ecological zones (AEZs) of The Democratic Republic of Congo and Burundi.Additional file 4: Figure S1. Multiple sequence alignment of the 11 Tp1 gene alleles obtained in this study.Additional file 5: Table S4. Estimates of evolutionary divergence between gene alleles for Tp1 and Tp2, using proportion nucleotide distance.Additional file 6: Table S5. Tp1 and Tp2 genes alleles with their corresponding antigen variants.Additional file 7: Table S6. Amino acid variants of Tp1 and Tp2 CD8+ T cell target epitopes of T. parva from DRC and Burundi.Additional file 8: Figure S2. Multiple sequence alignment of the 10 Tp2 gene alleles obtained in this study.Additional file 9: Table S7. Distribution of Tp1 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.Additional file 10: Table S8. Distribution of Tp2 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.Additional file 11: Figure S3. Neighbor-joining tree showing phylogenetic relationships among 48 Tp1 gene alleles described in Africa.Additional file 12: Figure S4. Phylogenetic tree showing the relationships among concatenated Tp1 and Tp2 nucleotide sequences of 93 T. parva samples from cattle in DRC and Burundi.This study is part of the PhD work supported by the University of Namur (UNamur, Belgium) through the UNamur-CERUNA institutional PhD grant awarded to GSA for bioinformatic analyses, interpretation of data and manuscript write up in Belgium. The laboratory aspects (molecular biology analysis) of the project were supported by the BecA-ILRI Hub through the Africa Biosciences Challenge Fund (ABCF) programme. The ABCF Programme is funded by the Australian Department for Foreign Affairs and Trade (DFAT) through the BecA-CSIRO partnership; the Syngenta Foundation for Sustainable Agriculture (SFSA); the Bill & Melinda Gates Foundation (BMGF); the UK Department for International Development (DFID); and the Swedish International Development Cooperation Agency (Sida). The ABCF Fellowship awarded to GAS was funded by BMGF grant (OPP1075938). Sample collection, field equipment and preliminary sample processing were supported through the “Theileria” project co-funded to the Université Evangélique en Afrique (UEA) by the Agence Universitaire de la Francophonie (AUF) and the Communauté Economique des Pays des Grands Lacs (CEPGL). The International Foundation for Science (IFS, Stockholm, Sweden) supported the individual scholarship awarded to GSA (grant no. IFS-92890CA3) for field work and part of field equipment to the “Theileria” project.http://www.parasitesandvectors.comam2020Veterinary Tropical Disease

Patterns of genetic diversity in southern and southeastern Araucaria angustifolia (Bert.) O. Kuntze relict populations

Habitat fragmentation and a decrease in population size may lead to a loss in population genetic diversity. For the first time, the reduction in genetic diversity in the northernmost limit of natural occurence (southeastern Brazil) of Araucaria angustifolia in comparison with populations in the main area of the species continuous natural distribution (southern Brazil), was tested. The 673 AFLPs markers revealed a high level of genetic diversity for the species (Ht = 0.27), despite anthropogenic influence throughout the last century, and a decrease of H in isolated populations of southeastern Brazil (H = 0.16), thereby indicating the tendency for higher genetic diversity in remnant populations of continuous forests in southern Brazil, when compared to natural isolated populations in the southeastern region. A strong differentiation among southern and southeastern populations was detected (AMOVA variance ranged from 10%-15%). From Bayesian analysis, it is suggested that the nine populations tested form five “genetic clusters” (K = 5). Five of these populations, located in the northernmost limit of distribution of the species, represent three “genetic clusters”. These results are in agreement with the pattern of geographic distribution of the studied populations

Nonoperative treatment of closed displaced midshaft clavicle fractures.

none7BACKGROUND: closed displaced midshaft clavicle fractures used to be treated nonoperatively, and many studies have reported that nonoperative treatment gave good results. However, more recent studies have reported poorer results following nonoperative treatment, whereas the results of operative treatment have improved considerably. The aim of this paper was to report the results of treating closed displaced midshaft clavicle fractures nonoperatively. MATERIALS AND METHODS: one hundred Edinburgh type 2B clavicle fractures (69 type 2B1 and 31 type 2B2) in 100 patients (78 males and 22 females) aged between 18 and 67 ears (mean 32 years) were treated. All patients were treated using a figure-of-eight bandage. Clinical and radiographic assessment was performed at the time of trauma, 1, 2 and 3 months after the trauma, and then at an average follow-up of 3 years (range 1-5 years). The outcome was rated at the last follow-up using the DASH score. RESULTS: ninety-seven of the 100 fractures healed. Three nonunions were observed. Average healing time was 9 weeks (range 8-12 weeks). No statistically significant correlation between the type of fracture and the healing time was observed. The average DASH score was 24 (range 0-78) and, based on this score, 81 patients presented excellent results, 12 good, 5 fair, and 2 poor. No statistically significant correlation between the type of the fracture and the score was observed. CONCLUSIONS: we believe that nonoperative treatment is still appropriate in most cases, as it yields good results without incurring the potential complications of surgery.noneFaldini C.; Nanni M.; Leonetti D.; Acri F.; Galante C.; Luciani D.; Giannini S.Faldini C.; Nanni M.; Leonetti D.; Acri F.; Galante C.; Luciani D.; Giannini S