Transcriptome profile of spleen tissues from locally-adapted Kenyan pigs (Sus scrofa) experimentally infected with three varying doses of a highly virulent African swine fever virus genotype IX isolate: Ken12/busia.1 (ken-1033).

BACKGROUND: African swine fever (ASF) is a lethal hemorrhagic disease affecting domestic pigs resulting in up to 100% mortality rates caused by the ASF virus (ASFV). The locally-adapted pigs in South-western Kenya have been reported to be resilient to disease and harsh climatic conditions and tolerate ASF; however, the mechanisms by which this tolerance is sustained remain largely unknown. We evaluated the gene expression patterns in spleen tissues of these locally-adapted pigs in response to varying infective doses of ASFV to elucidate the virus-host interaction dynamics. METHODS: Locally adapted pigs (n = 14) were experimentally infected with a high dose (1x106HAD50), medium dose (1x104HAD50), and low dose (1x102HAD50) of the highly virulent genotype IX ASFV Ken12/busia.1 (Ken-1033) isolate diluted in PBS and followed through the course of infection for 29 days. The in vivo pig host and ASFV pathogen gene expression in spleen tissues from 10 pigs (including three from each infective group and one uninfected control) were analyzed in a dual-RNASeq fashion. We compared gene expression between three varying doses in the host and pathogen by contrasting experiment groups against the naïve control. RESULTS: A total of 4954 differentially expressed genes (DEGs) were detected after ASFV Ken12/1 infection, including 3055, 1771, and 128 DEGs in the high, medium, and low doses, respectively. Gene ontology and KEGG pathway analysis showed that the DEGs were enriched for genes involved in the innate immune response, inflammatory response, autophagy, and apoptosis in lethal dose groups. The surviving low dose group suppressed genes in pathways of physiopathological importance. We found a strong association between severe ASF pathogenesis in the high and medium dose groups with upregulation of proinflammatory cytokines and immunomodulation of cytokine expression possibly induced by overproduction of prostaglandin E synthase (4-fold; p < 0.05) or through downregulation of expression of M1-activating receptors, signal transductors, and transcription factors. The host-pathogen interaction resulted in induction of expression of immune-suppressive cytokines (IL-27), inactivation of autophagy and apoptosis through up-regulation of NUPR1 [5.7-fold (high dose) and 5.1-fold (medium dose) [p < 0.05] and IL7R expression. We detected repression of genes involved in MHC class II antigen processing and presentation, such as cathepsins, SLA-DQB1, SLA-DOB, SLA-DMB, SLA-DRA, and SLA-DQA in the medium and high dose groups. Additionally, the host-pathogen interaction activated the CD8+ cytotoxicity and neutrophil machinery by increasing the expression of neutrophils/CD8+ T effector cell-recruiting chemokines (CCL2, CXCL2, CXCL10, CCL23, CCL4, CXCL8, and CXCL13) in the lethal high and medium dose groups. The recovered pigs infected with ASFV at a low dose significantly repressed the expression of CXCL10, averting induction of T lymphocyte apoptosis and FUNDC1 that suppressed neutrophilia. CONCLUSIONS: We provide the first in vivo gene expression profile data from locally-adapted pigs from south-western Kenya following experimental infection with a highly virulent ASFV genotype IX isolate at varying doses that mimic acute and mild disease. Our study showed that the locally-adapted pigs induced the expression of genes associated with tolerance to infection and repression of genes involved in inflammation at varying levels depending upon the ASFV dose administered.

Phylogenetic Distribution of Ralstonia solanacearum Species Complex Populations in Potato in Kenya.

Ralstonia solanacearum is a pathogen causing bacterial wilt disease of potato, resulting in 70% potato production losses in Kenya. A study was conducted to determine the diversity of R. solanacearum species complex strains within the main potato-growing regions of Kenya. Potato tubers were collected in different potato-growing regions of Kenya from visibly wilted potato plants as well as samples of tomato, irrigation water, and cultures for pathogen isolation. Genomic DNA was isolated from 135 purified cultures of RSSC isolates and PCR-amplified using multiplex and sequevar primers targeting the endoglucanase (egl) partial gene sequences. Pathogenicity tests using R. solanacearum strain (phylotype II sequevar I) were done on the cultivars Kenya Karibu, Shangi, Chulu, Wanjiku, and MoneyMaker. Phylogenetic analysis of the partial egl gene identified two genospecies, R. pseudosolanacearum sp. nov. (1.5%) and R. solanacearum (98.5%). All R. solanacearum strains clustered in sequevar I and were distributed in all the potato-growing regions surveyed. The cultivars were grown in a greenhouse for two cycles in a randomized complete block design and inoculated with R. solanacearum strain. The severity scores were assessed and the area under the disease progress curve (AUDPC) was determined. All the cultivars tested for pathogenicity exhibited wilting symptoms at varying intervals after infection, with none showing complete resistance to R. solanacearum. Cultivar Shangi exhibited minimum disease severity and progression of 41.14% and AUDPC of 1041.7, respectively, while 'Kenya Karibu' was the most susceptible with a high progression rate of 68.24% and AUDPC of 1897.5, respectively. 'MoneyMaker', 'Chulu', and 'Wanjiku' showed no significant difference in disease severity, depicting a simultaneous rate of infection among them. These findings provide valuable information to better understand the pathogen genetic diversity in Kenya and how it spreads.

Occurrence of a Novel Strain of Moroccan Watermelon Mosaic Virus Infecting Pumpkins in Kenya.

The Potyvirus Moroccan watermelon mosaic virus (MWMV) naturally infects and severely threatens production of cucurbits and papaya. In this study, we identified and characterized MWMV isolated from pumpkin (Cucurbita moschata) intercropped with MWMV-infected papaya plants through next-generation sequencing (NGS) and Sanger sequencing approaches. Complete MWMV genome sequences were obtained from two pumpkin samples through NGS and validated using Sanger sequencing. The isolates shared 83.4 to 83.7% nucleotide (nt) and 92.3 to 95.1% amino acid (aa) sequence identities in the coat protein and 79.5 to 79.9% nt and 89.2 to 89.7% aa identities in the polyprotein with papaya isolates of MWMV. Phylogenetic analysis using complete polyprotein nt sequences revealed the clustering of both pumpkin isolates of MWMV with corresponding sequences of cucurbit isolates of the virus from other parts of Africa and the Mediterranean regions, distinct from a clade formed by papaya isolates. Through sap inoculation, a pumpkin isolate of MWMV was pathogenic on zucchini (Cucurbita pepo), watermelon (Citrullus lanatus), and cucumber (Cucumis sativus) but not on papaya. Conversely, the papaya isolate of MWMV was nonpathogenic on pumpkin, watermelon, and cucumber, but it infected zucchini. The results suggest the occurrence of two strains of MWMV in Kenya having different biological characteristics associated with the host specificity.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The first complete genome sequence of the African swine fever virus genotype X and serogroup 7 isolated in domestic pigs from the Democratic Republic of Congo.

BACKGROUND: African swine fever (ASF), a highly contagious hemorrhagic disease, affects domestic pigs in the Democratic Republic of Congo (DRC) where regular outbreaks are reported leading to high mortality rates approaching 100% in the affected regions. No study on the characteristics of the complete genome of strains responsible for ASF outbreaks in the South Kivu province of DRC is available, limited a better understanding of molecular evolution and spread of this virus within the country. The present study aimed at determining the complete genome sequence of ASFV strains genotype X involved in 2018-2019 ASF disease outbreaks in South Kivu province of DRC. MATERIALS AND METHODS: Genomic DNA of a spleen sample from an ASFV genotype X-positive domestic pig in Uvira, during the 2018-2019 outbreaks in South Kivu, was sequenced using the Illumina HiSeq X platform. Obtained trimmed reads using Geneious Prime 2020.0.4 were blasted against a pig reference genome then contigs were generated from the unmapped reads enriched in ASFV DNA using Spades implemented in Geneious 2020.0.4. The assembly of the complete genome sequence of ASFV was achieved from the longest overlapping contigs. The new genome was annotated with the genome annotation transfer utility (GATU) software and the CLC Genomics Workbench 8 software was further used to search for any ORFs that failed to be identified by GATU. Subsequent analyses of the newly determined Uvira ASFV genotype X genome were done using BLAST for databases search, CLUSTAL W for multiple sequences alignments and MEGA X for phylogeny. RESULTS: 42 Gbp paired-end reads of 150 bp long were obtained containing about 0.1% of ASFV DNA. The assembled Uvira ASFV genome, termed Uvira B53, was 180,916 bp long that could be assembled in 2 contigs. The Uvira B53genome had a GC content of 38.5%, encoded 168 open reading frames (ORFs) and had 98.8% nucleotide identity with the reference ASFV genotype X Kenya 1950. The phylogenetic relationship with selected representative genomes clustered the Uvira B53 strain together with ASFV genotype X reported to date (Kenya 1950 and Ken05/Tk1). Multiple genome sequences comparison with the two reference ASFV genotype X strains showed that 130 of the 168 ORFs were fully conserved in the Uvira B53. The other 38 ORFs were divergent mainly due to SNPs and indels (deletions and insertions). Most of 46 multigene family (MGF) genes identified were affected by various genetic variations. However, 8 MGF ORFs present in Kenya 1950 and Ken05/Tk1 were absent from the Uvira B53 genome including three members of MGF 360, four of MGF 110 and one of MGF 100 while one MGF ORF (MGF 360-1L) at the left end of the genome was truncated in Uvira B53. Moreover, ORFs DP96R and p285L were also absent in the Uvira B53 genome. In contrast, the ORF MGF 110-5L present in Uvira B53 and Ken05/Tk1 was missing in Kenya 1950. The analysis of the intergenic region between the I73R and I329L genes also revealed sequence variations between the three genotype X strains mainly characterized by a deletion of 69 bp in Uvira B53 and 36 bp in Kenya 1950, compared to Ken05/Tk1. Assessment of the CD2v (EP402R) antigen unveiled the presence of SNPs and indels particularly in the PPPKPY tandem repeat region between selected variants representing the eight serogroups reported to date. Uvira B53 had identical CD2v variable region to the Uganda (KM609361) strain, the only other ASFV serogroup 7 reported to date. CONCLUSION: We report the first complete genome sequence of an African swine fever virus (ASFV) p72 genotype X and CD2v serogroup 7, termed Uvira B53. This study provides additional insights on genetic characteristics and evolution of ASFV useful for tracing the geographical spread of ASF and essential for improved design of control and management strategies against ASF.

Metagenomic analyses and genetic diversity of Tomato leaf curl Arusha virus affecting tomato plants in Kenya.

BACKGROUND: Tomato production is threatened worldwide by the occurrence of begomoviruses which are associated with tomato leaf curl diseases. There is little information on the molecular properties of tomato begomoviruses in Kenya, hence we investigated the population and genetic diversity of begomoviruses associated with tomato leaf curl in Kenya. METHODS: Tomato leaf samples with virus-like symptoms were obtained from farmers' field across the country in 2018 and Illumina sequencing undertaken to determine the genetic diversity of associated begomoviruses. Additionally, the occurrence of selection pressure and recombinant isolates within the population were also evaluated. RESULTS: Twelve complete begomovirus genomes were obtained from our samples with an average coverage of 99.9%. The sequences showed 95.7-99.7% identity among each other and 95.9-98.9% similarities with a Tomato leaf curl virus Arusha virus (ToLCArV) isolate from Tanzania. Analysis of amino acid sequences showed the highest identities in the regions coding for the coat protein gene (98.5-100%) within the isolates, and 97.1-100% identity with the C4 gene of ToLCArV. Phylogenetic algorithms clustered all Kenyan isolates in the same clades with ToLCArV, thus confirming the isolates to be a variant of the virus. There was no evidence of recombination within our isolates. Estimation of selection pressure within the virus population revealed the occurrence of negative or purifying selection in five out of the six coding regions of the sequences. CONCLUSIONS: The begomovirus associated with tomato leaf curl diseases of tomato in Kenya is a variant of ToLCArV, possibly originating from Tanzania. There is low genetic diversity within the virus population and this information is useful in the development of appropriate management strategies for the disease in the country.

First detection of African swine fever (ASF) virus genotype X and serogroup 7 in symptomatic pigs in the Democratic Republic of Congo.

BACKGROUND: African swine fever (ASF) is a highly contagious and severe hemorrhagic viral disease of domestic pigs. The analysis of variable regions of African swine fever virus (ASFV) genome led to more genotypic and serotypic information about circulating strains. The present study aimed at investigating the genetic diversity of ASFV strains in symptomatic pigs in South Kivu province of the Democratic Republic of Congo (DRC). MATERIALS AND METHODS: Blood samples collected from 391 ASF symptomatic domestic pigs in 6 of 8 districts in South Kivu were screened for the presence of ASFV, using a VP73 gene-specific polymerase chain reaction (PCR) with the universal primer set PPA1-PPA2. To genotype the strains, we sequenced and compared the nucleotide sequences of PPA-positive samples at three loci: the C-terminus of B646L gene encoding the p72 protein, the E183L gene encoding the p54 protein, and the central hypervariable region (CVR) of the B602L gene encoding the J9L protein. In addition, to serotype and discriminate between closely related strains, the EP402L (CD2v) gene and the intergenic region between the I73R and I329L genes were analyzed. RESULTS: ASFV was confirmed in 26 of 391 pigs tested. However, only 19 and 15 PPA-positive samples, respectively, were successfully sequenced and phylogenetically analyzed for p72 (B646L) and p54 (E183L). All the ASFV studied were of genotype X. The CVR tetrameric repeat clustered the ASFV strains in two subgroups: the Uvira subgroup (10 TRS repeats, AAAABNAABA) and another subgroup from all other strains (8 TRS repeats, AABNAABA). The phylogenetic analysis of the EP402L gene clustered all the strains into CD2v serogroup 7. Analyzing the intergenic region between I73R and I329L genes revealed that the strains were identical but contained a deletion of a 33-nucleotide internal repeat sequence compared to ASFV strain Kenya 1950. CONCLUSION: ASFV genotype X and serogroup 7 was identified in the ASF disease outbreaks in South Kivu province of DRC in 2018-2019. This represents the first report of ASFV genotype X in DRC. CVR tetrameric repeat sequences clustered the ASFV strains studied in two subgroups. Our finding emphasizes the need for improved coordination of the control of ASF.

Genomic analysis of Sweet potato feathery mottle virus from East Africa.

Sweet potato feathery mottle virus is a potyvirus that infect sweet potato. The genome of the virus was analysed to understand genetic diversity, evolution and gene flow. Motifs, nucleotide identity and a phylogenetic tree were used to determine phylogroup of the isolates. Gene flow and genetic diversity were tested using DnaSP v.5. Codons evolution were tested using three methods embedded in Datamonkey. The results indicate occurrence of an isolate of phylogroup B within East Africa. Low genetic differentiation was observed between isolates from Kenya and Uganda indicating evidence of gene flow between the two countries. Four genes were found to have positively selected codons bordering or occurring within functional motifs. A motif within P1 gene evolved differently between phylogroup A and B. The evidence of gene flow indicates frequent exchange of the virus between the two countries and P1 gene motif provide a possible marker that can be used for mapping the distribution of the phylogroups.

Serological and molecular evidence of Brucella species in the rapidly growing pig sector in Kenya.

BACKGROUND: Brucellosis is an emerging yet neglected zoonosis that has been reported in Kenya. Epidemiological data on brucellosis in ruminants is readily accessible; however, reports on brucellosis in pigs remain limited. This study sought to detect Brucella infection in pig serum by both serological and molecular techniques. Serum from 700 pigs randomly collected at a centralized abattoir in Nairobi region, Kenya were screened in parallel, using both Rose Bengal Test (RBT) and competitive Enzyme-Linked Immuno-sorbent Assay (cELISA) for antibodies against Brucella spp. All sera positive by RBT and 16 randomly selected negative samples were further tested using conventional PCR targeting bcsp31 gene and real-time PCR (RT-PCR) assays targeting IS711 and bcsp31 genes. RESULTS: A prevalence of 0.57% (n = 4/700) was estimated using RBT; none of these samples was positive on cELISA. All RBT positive sera were also positive by both PCRs, while two sero-negative samples also tested positive on RT-PCR (n = 6/20). Brucella abortus was detected in four out of the six PCR positive samples through a real-time multiplex PCR. CONCLUSION: The detection of antibodies against Brucella spp. and DNA in serum from slaughterhouse pigs confirm the presence of Brucella in pigs. Therefore, investigation of the epidemiology and role of pigs in the transmission of brucellosis in Kenya is needed. Further targeted studies would be useful to systematically quantify and identify the spp. of Brucella in pigs.

The Diagnostic Utility of Induced Sputum Microscopy and Culture in Childhood Pneumonia.

BACKGROUND.: Sputum microscopy and culture are commonly used for diagnosing the cause of pneumonia in adults but are rarely performed in children due to difficulties in obtaining specimens. Induced sputum is occasionally used to investigate lower respiratory infections in children but has not been widely used in pneumonia etiology studies. METHODS.: We evaluated the diagnostic utility of induced sputum microscopy and culture in patients enrolled in the Pneumonia Etiology Research for Child Health (PERCH) study, a large study of community-acquired pneumonia in children aged 1-59 months. Comparisons were made between induced sputum samples from hospitalized children with radiographically confirmed pneumonia and children categorized as nonpneumonia (due to the absence of prespecified clinical and laboratory signs and absence of infiltrate on chest radiograph). RESULTS.: One induced sputum sample was available for analysis from 3772 (89.1%) of 4232 suspected pneumonia cases enrolled in PERCH. Of these, sputum from 2608 (69.1%) met the quality criterion of <10 squamous epithelial cells per low-power field, and 1162 (44.6%) had radiographic pneumonia. Induced sputum microscopy and culture results were not associated with radiographic pneumonia, regardless of prior antibiotic use, stratification by specific bacteria, or interpretative criteria used. CONCLUSIONS.: The findings of this study do not support the culture of induced sputum specimens as a diagnostic tool for pneumonia in young children as part of routine clinical practice.

Etiology of severe childhood pneumonia in the Gambia, West Africa, determined by conventional and molecular microbiological analyses of lung and pleural aspirate samples.

Molecular analyses of lung aspirates from Gambian children with severe pneumonia detected pathogens more frequently than did culture and showed a predominance of bacteria, principally Streptococcus pneumoniae, >75% being of serotypes covered by current pneumococcal conjugate vaccines. Multiple pathogens were detected frequently, notably Haemophilus influenzae (mostly nontypeable) together with S. pneumoniae.

Diversity and functional analysis of rumen and fecal microbial communities associated with dietary changes in crossbreed dairy cattle.

The objective of this study was to investigate the effect of varying roughage and concentrate proportions, in diet of crossbreed dairy cattle, on the composition and associated functional genes of rumen and fecal microbiota. We also explored fecal samples as a proxy for rumen liquor samples. Six crossbred dairy cattle were reared on three diets with an increasing concentrate and reducing roughage amount in three consecutive 10-day periods. After each period, individual rumen liquor and fecal samples were collected and analyzed through shotgun metagenomic sequencing. Average relative abundance of identified Operational Taxonomic Units (OTU) and microbial functional roles from all animals were compared between diets and sample types (fecal and rumen liquor). Results indicated that dietary modifications significantly affected several rumen and fecal microbial OTUs. In the rumen, an increase in dietary concentrate resulted in an upsurge in the abundance of Proteobacteria, while reducing the proportions of Bacteroidetes and Firmicutes. Conversely, changes in microbial composition in fecal samples were not consistent with dietary modification patterns. Microbial functional pathway classification identified that carbohydrate metabolism and protein metabolism pathways dominated microbial roles. Assessment of dietary effects on the predicted functional roles of these microbiota revealed that a high amount of dietary concentrate resulted in an increase in central carbohydrate metabolism and a corresponding reduction in protein synthesis. Moreover, we identified several microbial stress-related responses linked to dietary changes. Bacteroides and Clostridium genera were the principal hosts of these microbial functions. Therefore, the roughage to concentrate proportion has more influence on the microbial composition and microbial functional genes in rumen samples than fecal samples. As such, we did not establish a significant relationship between the rumen and fecal metagenome profiles, and the rumen and fecal microbiota from one animal did not correlate more than those from different animals.

Aetiology of lobar pneumonia determined by multiplex molecular analyses of lung and pleural aspirate specimens in the Gambia: findings from population-based pneumonia surveillance.

OBJECTIVES: To determine the causes of lobar pneumonia in rural Gambia. DESIGN AND SETTING: Population-based pneumonia surveillance at seven peripheral health facilities and two regional hospitals in rural Gambia. 7-valent pneumococcal conjugate vaccine (PCV7) was introduced routinely in August 2009 and replaced by PCV13 from May 2011. METHODS: Prospective pneumonia surveillance was undertaken among all ages with referral of suspected pneumonia cases to the regional hospitals. Blood culture and chest radiographs were performed routinely while lung or pleural aspirates were collected from selected, clinically stable patients with pleural effusion on radiograph and/or large, dense, peripheral consolidation. We used conventional microbiology, and from 8 April 2011 to 17 July 2012, used a multiplex PCR assay on lung and pleural aspirates. We calculated proportions with pathogens, associations between coinfecting pathogens and PCV effectiveness. PARTICIPANTS: 2550 patients were admitted with clinical pneumonia; 741 with lobar pneumonia or pleural effusion. We performed 181 lung or pleural aspirates and multiplex PCR on 156 lung and 4 pleural aspirates. RESULTS: Pathogens were detected in 116/160 specimens, the most common being Streptococcus pneumoniae(n=68), Staphylococcus aureus (n=26) and Haemophilus influenzae type b (n=11). Bacteria (n=97) were more common than viruses (n=49). Common viruses were bocavirus (n=11) and influenza (n=11). Coinfections were frequent (n=55). Moraxella catarrhalis was detected in eight patients and in every case there was coinfection with S. pneumoniae. The odds ratio of vaccine-type pneumococcal pneumonia in patients with two or three compared with zero doses of PCV was 0.17 (95% CI 0.06 to 0.51). CONCLUSIONS: Lobar pneumonia in rural Gambia was caused primarily by bacteria, particularly S. pneumoniae and S. aureus. Coinfection was common and M. catarrhalis always coinfected with S. pneumoniae. PCV was highly efficacious against vaccine-type pneumococcal pneumonia.

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.

Haplotype analysis of the mitochondrial DNA d-loop region reveals the maternal origin and historical dynamics among the indigenous goat populations in east and west of the Democratic Republic of Congo.

This study aimed at assessing haplotype diversity and population dynamics of three Congolese indigenous goat populations that included Kasai goat (KG), small goat (SG), and dwarf goat (DG) of the Democratic Republic of Congo (DRC). The 1169 bp d-loop region of mitochondrial DNA (mtDNA) was sequenced for 339 Congolese indigenous goats. The total length of sequences was used to generate the haplotypes and evaluate their diversities, whereas the hypervariable region (HVI, 453 bp) was analyzed to define the maternal variation and the demographic dynamic. A total of 568 segregating sites that generated 192 haplotypes were observed from the entire d-loop region (1169 bp d-loop). Phylogenetic analyses using reference haplotypes from the six globally defined goat mtDNA haplogroups showed that all the three Congolese indigenous goat populations studied clustered into the dominant haplogroup A, as revealed by the neighbor-joining (NJ) tree and median-joining (MJ) network. Nine haplotypes were shared between the studied goats and goat populations from Pakistan (1 haplotype), Kenya, Ethiopia and Algeria (1 haplotype), Zimbabwe (1 haplotype), Cameroon (3 haplotypes), and Mozambique (3 haplotypes). The population pairwise analysis (FST ) indicated a weak differentiation between the Congolese indigenous goat populations. Negative and significant (p-value <.05) values for Fu's Fs (-20.418) and Tajima's (-2.189) tests showed the expansion in the history of the three Congolese indigenous goat populations. These results suggest a weak differentiation and a single maternal origin for the studied goats. This information will contribute to the improvement of the management strategies and long-term conservation of indigenous goats in DRC.

Prevalence of tick-transmitted pathogens in cattle reveals that Theileria parva, Babesia bigemina and Anaplasma marginale are endemic in Burundi.

BACKGROUND: Tick-borne diseases (TBDs) constitute a major constraint for livestock development in sub-Saharan Africa, with East Coast fever (ECF) being the most devastating TBD of cattle. However, in Burundi, detailed information is lacking on the current prevalence of TBDs and on the associated economic losses from mortality and morbidity in cattle as well as the costs associated with TBD control and treatment. The aim of this study was, therefore, to assess the prevalence and spatial distribution of tick-borne pathogens (TBPs) in cattle across the major agro-ecological zones (AEZs) in Burundi. METHODS: In a cross-sectional study conducted in ten communes spanning the five main AEZs in Burundi, blood samples were taken from 828 cattle from 305 farms between October and December 2017. Evidence of Theileria parva infection was assessed by antibody level, measured using a polymorphic immunodominant molecule (PIM) antigen-based enzyme-linked immunosorbent assay (ELISA) and by a T. parva-specific p104 gene-based nested PCR. Antibodies against Theileria mutans infection were detected using the 32-kDa antigen-based indirect ELISA, while the 200-kDa antigen and the major surface protein 5 (MSP5)-based indirect ELISA were used to detect antibodies against Babesia bigemina and Anaplasma marginale, respectively. RESULTS: The prevalence of T. parva across the ten communes sampled ranged from 77.5 to 93.1% and from 67.8 to 90.0% based on the ELISA and PCR analysis, respectively. A statistically significant difference in infection was observed between calves and adult cattle; however, T. parva infection levels were not significantly associated with sex and breed. The seroprevalence indicating exposure to T. mutans, B. bigemina and A. marginale ranged from 30 to 92.1%, 33.7 to 90% and 50 to 96.2%, respectively. Mixed infections of TBPs were detected in 82.91% of cattle sampled, with 11 different combinations of pathogen species detected . CONCLUSIONS: The findings indicate that T. parva, A. marginale and B. bigemina infections are endemic in Burundi. Knowledge of the spatial distribution of TBPs will facilitate the design of effective targeted strategies to control these diseases. There is a need for further investigations of the distribution of tick vectors and the population structure of TBPs in order to identify the key epidemiological factors contributing to TBD outbreaks in Burundi.

Molecular survey of cattle ticks in Burundi: First report on the presence of the invasive Rhipicephalus microplus tick.

A recent research study on prevalence of tick-borne pathogens in Burundi reported high prevalence and endemicity of Theileria parva, Anaplasma marginale and Babesia bigemina infections in cattle. Detailed information about tick species infesting animals, their distribution and genetic diversity in Burundi is outdated and limited. This study therefore assessed the prevalence and genetic diversity of tick species infesting cattle across agroecological zones (AEZs) in Burundi. A cross-sectional study on the occurrence of tick species was conducted in 24 districts of Burundi between October and December 2017. Differential identification and characterization of ticks collected was conducted using tick morphological keys and molecular tools (cox1 and 12S rRNA gene). Chi-square test was used to test for association between agroecological zones and the prevalence of tick species. Phylogenetic relationships were inferred using bayesian and maximum likelihood algorithms. A total of 483 ticks were collected from the five AEZs sampled. Six tick species comprising of Rhipicephalus appendiculatus, R. sanguineus, R. evertsi evertsi, R. microplus, R. decoloratus and Amblyomma variegatum were observed. Rhipicephalus appendiculatus were the most prevalent ticks (~45%). A total of 138 specimens (28%) were found to be Rhipicephalus microplus, suggesting an emerging threat for cattle farmers. Twelve R. appendiculatus cox1 haplotypes were obtained from 106 specimens that were sequenced. Two cox1 haplotypes of R. microplus which clustered into previously reported Clade A were observed. Rhipicephalus sanguineus and R. evertsi evertsi ticks, the vectors of numerous zoonotic pathogens, were collected from cattle, which constitute a high risk for public health. These findings reveal an overlapping distribution of tick vectors in Burundi. The design of ticks and tick-borne diseases control strategies should consider the distribution of different vectors across the AEZs particularly the presence of the highly invasive R. microplus tick in Burundi and the potential risk of introducing the pathogenic Babesia bovis.

African Swine Fever Virus (ASFV): Biology, Genomics and Genotypes Circulating in Sub-Saharan Africa.

African swine fever (ASF) is a highly infectious and fatal haemorrhagic disease of pigs that is caused by a complex DNA virus of the genus Asfivirus and Asfarviridae African suids family. The disease is among the most devastating pig diseases worldwide including Africa. Although the disease was first reported in the 19th century, it has continued to spread in Africa and other parts of the world. Globally, the rising demand for pork and concomitant increase in transboundary movements of pigs and pork products is likely to increase the risk of transmission and spread of ASF and pose a major challenge to the pig industry. Different genotypes of the ASF virus (ASFV) with varying virulence have been associated with different outbreaks in several countries in sub-Saharan Africa (SSA) and worldwide, and understanding genotype circulation will be important for ASF prevention and control strategies. ASFV genotypes unique to Africa have also been reported in SSA. This review briefly recounts the biology, genomics and genotyping of ASFV and provides an account of the different genotypes circulating in SSA. The review also highlights prevention, control and progress on vaccine development and identifies gaps in knowledge of ASFV genotype circulation in SSA that need to be addressed.

Comparative Analysis of SLA-1, SLA-2, and DQB1 Genetic Diversity in Locally-Adapted Kenyan Pigs and Their Wild Relatives, Warthogs.

Swine leukocyte antigen (SLA) plays a central role in controlling the immune response by discriminating self and foreign antigens and initiating an immune response. Studies on SLA polymorphism have demonstrated associations between SLA allelic variants, immune response, and disease resistance. The SLA polymorphism is due to host-pathogen co-evolution resulting in improved adaptation to diverse environments making SLA a crucial genomic region for comparative diversity studies. Although locally-adapted African pigs have small body sizes, they possess increased resilience under harsh environmental conditions and robust immune systems with reported tolerance to some diseases, including African swine fever. However, data on the SLA diversity in these pigs are not available. We characterized the SLA of unrelated locally-adapted domestic pigs from Homa Bay, Kenya, alongside exotic pigs and warthogs. We undertook SLA comparative diversity of the functionally expressed SLA class I (SLA-1, SLA-2) and II (DQB1) repertoires in these three suids using the reverse transcription polymerase chain reaction (RT-PCR) sequence-based typing (SBT) method. Our data revealed higher genetic diversity in the locally-adapted pigs and warthogs compared to the exotic pigs. The nucleotide substitution rates were higher in the peptide-binding regions of the SLA-1, SLA-2, and DQB1 loci, indicative of adaptive evolution. We obtained high allele frequencies in the three SLA loci, including some breed-specific private alleles, which could guide breeders to increase their frequency through selection if confirmed to be associated with enhanced resilience. Our study contributes to the growing body of knowledge on genetic diversity in free-ranging animal populations in their natural environment, availing the first DQB1 gene data from locally-adapted Kenyan pigs.

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

African 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 africanus). 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 selected using convenience sampling along vehicle-accessible transects within the national 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.

The first genotype II African swine fever virus isolated in Africa provides insight into the current Eurasian pandemic.

African swine fever (ASF) caused by the African swine fever virus (ASFV) is ranked by OIE as the most important source of mortality in domestic pigs globally and is indigenous to African wild suids and soft ticks. Despite two ASFV genotypes causing economically devastating epidemics outside the continent since 1961, there have been no genome-level analyses of virus evolution in Africa. The virus was recently transported from south-eastern Africa to Georgia in 2007 and has subsequently spread to Russia, eastern Europe, China, and south-east Asia with devastating socioeconomic consequences. To date, two of the 24 currently described ASFV genotypes defined by sequencing of the p72 gene, namely genotype I and II, have been reported outside Africa, with genotype II being responsible for the ongoing pig pandemic. Multiple complete genotype II genome sequences have been reported from European, Russian and Chinese virus isolates but no complete genome sequences have yet been reported from Africa. We report herein the complete genome of a Tanzanian genotype II isolate, Tanzania/Rukwa/2017/1, collected in 2017 and determined using an Illumina short read strategy. The Tanzania/Rukwa/2017/1 sequence is 183,186 bp in length (in a single contig) and contains 188 open reading frames. Considering only un-gapped sites in the pairwise alignments, the new sequence has 99.961% identity with the updated Georgia 2007/1 reference isolate (FR682468.2), 99.960% identity with Polish isolate Pol16_29413_o23 (MG939586) and 99.957% identity with Chinese isolate ASFV-wbBS01 (MK645909.1). This represents 73 single nucleotide polymorphisms (SNPs) relative to the Polish isolate and 78 SNPs with the Chinese genome. Phylogenetic analysis indicated that Tanzania/Rukwa/2017/1 clusters most closely with Georgia 2007/1. The majority of the differences between Tanzania/Rukwa/2017/1 and Georgia 2007/1 genotype II genomes are insertions/deletions (indels) as is typical for ASFV. The indels included differences in the length and copy number of the terminal multicopy gene families, MGF 360 and 110. The Rukwa2017/1 sequence is the first complete genotype II genome from a precisely mapped locality in Africa, since the exact origin of Georgia2007/1 is unknown. It therefore provides baseline information for future analyses of the diversity and phylogeography of this globally important genetic sub-group of ASF viruses.