Detection of African swine fever virus genotype XV in a sylvatic cycle in Saadani National Park, Tanzania

This research article was published by Wiley Online Library, 2020African swine fever (ASF) is a severe haemorrhagic disease of domestic pigs caused by ASF virus (ASFV). ASFV is transmitted by soft ticks (Ornithodoros moubata complex group) and by direct transmission. In Africa, ASF is maintained in transmission cycles of asymptomatic infection involving wild suids, mainly warthogs (Phacochoerus afri canus). ASF outbreaks have been reported in many parts of Tanzania; however, active surveillance has been limited to pig farms in a few geographical locations. There is an information gap on whether and where the sylvatic cycle may occur independently of domestic pigs. To explore the existence of a sylvatic cycle in Saadani National Park in Tanzania, blood and serum samples were collected from 19 warthogs se lected using convenience sampling along vehicle-accessible transects within the na tional park. The ticks were sampled from warthog burrows. Blood samples and ticks were subjected to ASFV molecular diagnosis (PCR) and genotyping, and warthog sera were subjected to serological (indirect ELISA) testing for ASFV antibody detection. All warthog blood samples were PCR-negative, but 16/19 (84%) of the warthog sera were seropositive by ELISA confirming exposure of warthogs to ASFV. Of the ticks sampled, 20/111 (18%) were positive for ASFV by conventional PCR. Sequencing of the p72 virus gene fragments showed that ASF viruses detected in ticks belonged to genotype XV. The results confirm the existence of a sylvatic cycle of ASFV in Saadani National Park, Tanzania, that involves ticks and warthogs independent of domestic pigs. Our findings suggest that genotype XV previously reported in 2008 in Tanzania is likely to be widely distributed and involved in both wild and domestic infection cycles. Whole-genome sequencing and analysis of the ASFV genotype XV circulating in Tanzania is recommended to determine the phylogeny of the viruses

Comprehensive transcriptome of the maize stalk borer, Busseola fusca, from multiple tissue types, developmental stages, and parasitoid wasp exposures

International audienc

Genetic variation of LEI0258 locus at major histocompatibility complex (MHC) region in Ethiopian indigenous village chicken

Indigenous chickens are locally adapted to environmental challenges and provide subsistence to millions of farmers in Africa. However, their productivity remains low compared to exotic strains. Efforts are being made to combine the local adaptation of indigenous chicken with productive traits of exotic chicken. Understanding the link between genetic diversity and environmental challenges leads to marker-assisted breed improvement programs for sustainable chicken production at smallholder level. Genetic variation at LEI0258 VNTR locus located within the MHC region has been linked to infectious disease resistance/susceptibility in commercial breeds. The aim of this study was to investigate allelic variability, genetic diversity and genetic relationships of 24 chicken populations in Ethiopia. Here, the diversity at LEI0258 in 236 chickens from 24 Ethiopian indigenous chicken populations using the major Histo-compatibility Complex linked LEI0258 marker is reported. A total of 236 DNA samples were genotyped by capillary electrophoresis from 24 chicken populations. The number of alleles, allele frequency, and heterozygosity levels were used to measure genetic variation at LEI0258 locus in Ethiopian indigenous village chicken. Twenty-nine LEI0258 alleles were observed using capillary electrophoresis that ranged from 185 to 569 bp with no significant difference in allele frequencies between populations. The number of alleles ranged from 179 (Meseret) to 569 (Batambie), with an average of 9.6 alleles per population. Allelic polymorphism was further evaluated through genotyping by Sanger sequencing. Twenty-three DNA samples with different fragment sizes were re-amplified and their alleles sequenced to depict polympormisms based on the combination of two repeat regions at 12 bp and 13 bp, respectively, and flanking regions with SNP and indels. The repeat region at 12 bp appeared 2 to 18 times, whereas the region at 13 bp appeared invariant in all populations. Sequence relationships revealed two distinct groups of alleles. The number of indels and mutations were 33 and 17, respectively. From capillary electrophoresis, the fixation coefficient of the sub-population within the total population (FST), inbreeding/fixation/ coefficient of an individual in a sub population (FIS) and total inbreeding /heterozygosity deficit/ coefficient of an individual within the total population (FIT) in the locus was 0.03, 0.08 and 0.11, respectively. Three percent of the genetic diversity was due to differences among populations, where as 8% and 89% were variations among individuals and variations within individuals, respectively. Despite the overall low genetic differentiation, both fragment and sequencing analysis revealed high allelic and genetic variability across the 24 populations. The high diversity at LEI0258 in Ethiopian indigenous village chicken populations supports the importance of the MHC region in relation to the disease challenges faced by smallholder poultry farmers across Ethiopia. We recommend that breed improvement programs ensure the maintenance of this diversity by selecting breeding stock as diverse as possible at the LEI0258 locus

Detection of antimicrobial resistance, pathogenicity, and virulence potentials of non-typhoidal Salmonella isolates at the Yaounde abattoir using whole-genome sequencing technique

One of the crucial public health problems today is the emerging and re-emerging of multidrug-resistant (MDR) bacteria coupled with a decline in the development of new antimicrobials. Non-typhoidal Salmonella (NTS) is classified among the MDR pathogens of international concern. To predict their MDR potentials, 23 assembled genomes of NTS from live cattle (n = 1), beef carcass (n = 19), butchers’ hands (n = 1) and beef processing environments (n = 2) isolated from 830 wet swabs at the Yaounde abattoir between December 2014 and November 2015 were explored using whole-genome sequencing. Phenotypically, while 22% (n = 5) of Salmonella isolates were streptomycin-resistant, 13% (n = 3) were MDR. Genotypically, all the Salmonella isolates possessed high MDR potentials against several classes of antibiotics including critically important drugs (carbapenems, third-generation cephalosporin and fluoroquinolone). Moreover, >31% of NTS exhibited resistance potentials to polymyxin, considered as the last resort drug. Additionally, ≤80% of isolates harbored “silent resistant genes” as a potential reservoir of drug resistance. Our isolates showed a high degree of pathogenicity and possessed key virulence factors to establish infection even in humans. Whole-genome sequencing unveiled both broader antimicrobial resistance (AMR) profiles and inference of pathogen characteristics. This study calls for the prudent use of antibiotics and constant monitoring of AMR of NTS

A global metagenomic map of urban microbiomes and antimicrobial resistance

We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities.Funding: the Tri-I Program in Computational Biology and Medicine (CBM) funded by NIH grant 1T32GM083937; GitHub; Philip Blood and the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant number ACI-1548562 and NSF award number ACI-1445606; NASA (NNX14AH50G, NNX17AB26G), the NIH (R01AI151059, R25EB020393, R21AI129851, R35GM138152, U01DA053941); STARR Foundation (I13- 0052); LLS (MCL7001-18, LLS 9238-16, LLS-MCL7001-18); the NSF (1840275); the Bill and Melinda Gates Foundation (OPP1151054); the Alfred P. Sloan Foundation (G-2015-13964); Swiss National Science Foundation grant number 407540_167331; NIH award number UL1TR000457; the US Department of Energy Joint Genome Institute under contract number DE-AC02-05CH11231; the National Energy Research Scientific Computing Center, supported by the Office of Science of the US Department of Energy; Stockholm Health Authority grant SLL 20160933; the Institut Pasteur Korea; an NRF Korea grant (NRF-2014K1A4A7A01074645, 2017M3A9G6068246); the CONICYT Fondecyt Iniciación grants 11140666 and 11160905; Keio University Funds for Individual Research; funds from the Yamagata prefectural government and the city of Tsuruoka; JSPS KAKENHI grant number 20K10436; the bilateral AT-UA collaboration fund (WTZ:UA 02/2019; Ministry of Education and Science of Ukraine, UA:M/84-2019, M/126-2020); Kyiv Academic Univeristy; Ministry of Education and Science of Ukraine project numbers 0118U100290 and 0120U101734; Centro de Excelencia Severo Ochoa 2013–2017; the CERCA Programme / Generalitat de Catalunya; the CRG-Novartis-Africa mobility program 2016; research funds from National Cheng Kung University and the Ministry of Science and Technology; Taiwan (MOST grant number 106-2321-B-006-016); we thank all the volunteers who made sampling NYC possible, Minciencias (project no. 639677758300), CNPq (EDN - 309973/2015-5), the Open Research Fund of Key Laboratory of Advanced Theory and Application in Statistics and Data Science – MOE, ECNU, the Research Grants Council of Hong Kong through project 11215017, National Key RD Project of China (2018YFE0201603), and Shanghai Municipal Science and Technology Major Project (2017SHZDZX01) (L.S.