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1.
Emerg Infect Dis ; 28(4): 888-890, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35318934

RESUMO

Leishmaniases are neglected tropical diseases of humans and animals. We detected Leishmania infantum in 3 mixed-breed dogs in Zambia that had no travel history outside the country. Our findings suggest presence of and probable emergence of leishmaniasis in Zambia, indicating the need for physicians and veterinarians to consider the disease during diagnosis.


Assuntos
Leishmania infantum , Leishmaniose , Animais , Cães , Leishmaniose/veterinária , Doenças Negligenciadas , Probabilidade , Zâmbia/epidemiologia
2.
Parasitology ; : 1-8, 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35481462

RESUMO

Theileria parva is an apicomplexan protozoan parasite that causes bovine theileriosis (East Coast Fever; ECF) in central, eastern and southern Africa. In Malawi, ECF is endemic in the northern and central regions where it has negatively affected the development of dairy industry. Despite its endemic status the genetic population structure of T. parva in Malawi is currently unknown. To obtain an understanding of T. parva in Malawi, we performed population genetics analysis of T. parva populations in cattle vaccinated with the Muguga cocktail live vaccine and non-vaccinated cattle using mini- and microsatellite markers covering all the four T. parva chromosomes. The T. parva Muguga strain was included in this study as a reference strain. Linkage disequilibrium was observed when all samples were treated as a single population. There was sub-structuring among the samples as shown by the principal coordinate analysis. Majority of the samples clustered with the T. parva Muguga reference strain suggesting that the isolates in Malawi are closely related to the vaccine component, which support the current use of Muguga cocktail vaccine to control ECF. The clustering of samples from non-endemic southern region with those from endemic central region suggests expansion of the distribution of T. parva in Malawi.

3.
Emerg Infect Dis ; 27(8): 2237-2239, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34287134

RESUMO

Rickettsia asembonensis is a flea-related Rickettsia with unknown pathogenicity to humans. We detected R. asembonensis DNA in 2 of 1,153 human blood samples in Zambia. Our findings suggest the possibility of R. asembonensis infection in humans despite its unknown pathogenicity.


Assuntos
Infecções por Rickettsia , Rickettsia felis , Rickettsia , Sifonápteros , Animais , Humanos , Rickettsia/genética , Infecções por Rickettsia/diagnóstico , Infecções por Rickettsia/epidemiologia , Zâmbia/epidemiologia
4.
Parasitol Res ; 120(1): 267-276, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33225402

RESUMO

Tick-borne pathogens (TBPs) in dogs have attracted much attention over the last decade since some are now known to be zoonotic and pose a threat to both animal and human health sectors. Despite the increase in the number of studies on canine TBPs worldwide, only a few studies have been conducted in resource-limited countries where research priority is given to food animals than companion animals. In the present study, the occurrence of TBPs of the genera Babesia, Hepatozoon, Anaplasma, and Ehrlichia was investigated in 209 owned and stray dogs in three major cities in Malawi through molecular techniques. Among the examined dogs, 93 (44.5%) were infected with at least one TBP. The detection rates were 23.1% for Babesia rossi, 2.9% for B. vogeli, 19.1% for Hepatozoon canis, 2.4% for Anaplasma platys, and 3.8% for Ehrlichia canis. This is the first molecular study that has provided evidence that dogs in Malawi are infected with TBPs. Sensitization is required for veterinary practitioners, dog handlers, and pet owners as the detected pathogens affect the animals' wellbeing. Further studies focusing on rural areas with limited or no access to veterinary care are required to ascertain the extent of the TBP infection in dogs.


Assuntos
Anaplasma/isolamento & purificação , Babesia/isolamento & purificação , Doenças do Cão/epidemiologia , Ehrlichia canis/isolamento & purificação , Eucoccidiida/isolamento & purificação , Doenças Transmitidas por Carrapatos/epidemiologia , Anaplasma/classificação , Anaplasma/genética , Animais , Babesia/classificação , Babesia/genética , Cidades , Coinfecção/parasitologia , Doenças do Cão/parasitologia , Cães , Ehrlichia canis/classificação , Ehrlichia canis/genética , Eucoccidiida/classificação , Eucoccidiida/genética , Malaui/epidemiologia , Doenças Transmitidas por Carrapatos/parasitologia , Carrapatos/parasitologia
5.
J Hum Genet ; 65(1): 41-48, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31723216

RESUMO

Neochlamydia strain S13 is an amoebal symbiont of an Acanthamoeba sp. The symbiont confers resistance to Legionella pneumophila on its host; however, the molecular mechanism underlying this resistance is not completely understood. Genome analyses have been crucial for understanding the complicated host-symbiont relationship but segregating the host's genome DNA from the symbiont's DNA is often challenging. In this study, we successfully identified a bimodal genomic structure in Neochlamydia strain S13 using PacBio RS II supported by ultra-long reads derived from MinION. One mode consisted of circular sequences of 2,586,667 and 231,307 bp; the other was an integrated sequence of the two via long homologous regions. They encoded 2175 protein-coding regions, some of which were implied to be acquired via horizontal gene transfer. They were specifically conserved in the genus Neochlamydia and formed a cluster in the genome, presumably by multiplication through genome replication. Moreover, it was notable that the sequenced DNA was obtained without segregating the symbiont DNA from the host. This is an easy and versatile technique that facilitates the characterization of diverse hosts and symbionts in nature.


Assuntos
Genoma Bacteriano , Bactérias Gram-Negativas/genética , Análise de Sequência de DNA/instrumentação , Acanthamoeba/microbiologia , Genômica/métodos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/isolamento & purificação , Filogenia , Análise de Sequência de DNA/métodos
6.
Int J Mol Sci ; 21(20)2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33053895

RESUMO

Efforts to determine the mosquito genes that affect dengue virus replication have identified a number of candidates that positively or negatively modify amplification in the invertebrate host. We used deep sequencing to compare the differential transcript abundances in Aedes aegypti 14 days post dengue infection to those of uninfected A. aegypti. The gene lethal(2)-essential-for-life [l(2)efl], which encodes a member of the heat shock 20 protein (HSP20) family, was upregulated following dengue virus type 2 (DENV-2) infection in vivo. The transcripts of this gene did not exhibit differential accumulation in mosquitoes exposed to insecticides or pollutants. The induction and overexpression of l(2)efl gene products using poly(I:C) resulted in decreased DENV-2 replication in the cell line. In contrast, the RNAi-mediated suppression of l(2)efl gene products resulted in enhanced DENV-2 replication, but this enhancement occurred only if multiple l(2)efl genes were suppressed. l(2)efl homologs induce the phosphorylation of eukaryotic initiation factor 2α (eIF2α) in the fruit fly Drosophila melanogaster, and we confirmed this finding in the cell line. However, the mechanism by which l(2)efl phosphorylates eIF2α remains unclear. We conclude that l(2)efl encodes a potential anti-dengue protein in the vector mosquito.


Assuntos
Aedes/genética , Aedes/virologia , Vírus da Dengue/fisiologia , Dengue/virologia , Proteínas de Choque Térmico HSP20/genética , Proteínas de Insetos/genética , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , Animais , Biologia Computacional/métodos , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno , Transcriptoma , Replicação Viral
7.
Malar J ; 17(1): 217, 2018 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-29843734

RESUMO

BACKGROUND: The recent spread of artemisinin (ART)-resistant Plasmodium falciparum represents an emerging global threat to public health. In Southeast Asia, the C580Y mutation of kelch13 (k13) is the dominant mutation of ART-resistant P. falciparum. Therefore, a simple method for the detection of C580Y mutation is urgently needed to enable widespread routine surveillance in the field. The aim of this study is to develop a new diagnostic procedure for the C580Y mutation using loop-mediated isothermal amplification (LAMP) combined with the MinION nanopore sequencer. RESULTS: A LAMP assay for the k13 gene of P. falciparum to detect the C580Y mutation was successfully developed. The detection limit of this procedure was 10 copies of the reference plasmid harboring the k13 gene within 60 min. Thereafter, amplicon sequencing of the LAMP products using the MinION nanopore sequencer was performed to clarify the nucleotide sequences of the gene. The C580Y mutation was identified based on the sequence data collected from MinION reads 30 min after the start of sequencing. Further, clinical evaluation of the LAMP assay in 34 human blood samples collected from patients with P. falciparum malaria in Indonesia revealed a positive detection rate of 100%. All LAMP amplicons of up to 12 specimens were simultaneously sequenced using MinION. The results of sequencing were consistent with those of the conventional PCR and Sanger sequencing protocol. All procedures from DNA extraction to variant calling were completed within 3 h. The C580Y mutation was not found among these 34 P. falciparum isolates in Indonesia. CONCLUSIONS: An innovative method combining LAMP and MinION will enable simple, rapid, and high-sensitivity detection of the C580Y mutation of P. falciparum, even in resource-limited situations in developing countries.


Assuntos
Malária Falciparum/classificação , Mutação , Técnicas de Amplificação de Ácido Nucleico/métodos , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Humanos , Indonésia , Malária Falciparum/parasitologia , Nanoporos , Plasmodium falciparum/isolamento & purificação
8.
BMC Infect Dis ; 17(1): 621, 2017 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-28903726

RESUMO

BACKGROUND: A simple and accurate molecular diagnostic method for malaria is urgently needed due to the limitations of conventional microscopic examination. In this study, we demonstrate a new diagnostic procedure for human malaria using loop mediated isothermal amplification (LAMP) and the MinION™ nanopore sequencer. METHODS: We generated specific LAMP primers targeting the 18S-rRNA gene of all five human Plasmodium species including two P. ovale subspecies (P. falciparum, P. vivax, P. ovale wallikeri, P. ovale curtisi, P. knowlesi and P. malariae) and examined human blood samples collected from 63 malaria patients in Indonesia. Additionally, we performed amplicon sequencing of our LAMP products using MinION™ nanopore sequencer to identify each Plasmodium species. RESULTS: Our LAMP method allowed amplification of all targeted 18S-rRNA genes of the reference plasmids with detection limits of 10-100 copies per reaction. Among the 63 clinical samples, 54 and 55 samples were positive by nested PCR and our LAMP method, respectively. Identification of the Plasmodium species by LAMP amplicon sequencing analysis using the MinION™ was consistent with the reference plasmid sequences and the results of nested PCR. CONCLUSIONS: Our diagnostic method combined with LAMP and MinION™ could become a simple and accurate tool for the identification of human Plasmodium species, even in resource-limited situations.


Assuntos
Malária/diagnóstico , Técnicas de Amplificação de Ácido Nucleico/métodos , Primers do DNA , Humanos , Indonésia , Limite de Detecção , Malária Falciparum/diagnóstico , Malária Vivax/diagnóstico , Técnicas de Diagnóstico Molecular/instrumentação , Técnicas de Diagnóstico Molecular/métodos , Nanoporos , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Plasmodium/genética , Reação em Cadeia da Polimerase , RNA Ribossômico 18S
9.
Exp Parasitol ; 166: 10-5, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26965399

RESUMO

Babesia bovis is an apicomplexan hemoprotozoan that can invade bovine red blood cells (RBCs), where it multiplies asexually. RBC invasion assays using free viable merozoites are now routinely used to understand the invasion mechanism of B. bovis, and to evaluate the efficacy of chemicals and antibodies that potentially inhibit RBC invasion by the parasite. The application of high-voltage pulses (high-voltage electroporation), a commonly used method to isolate free merozoites from infected RBCs, reduces the viability of the merozoites. Recently, a cold treatment of B. bovis in vitro culture was found to induce an effective release of merozoites from the infected RBCs. In the present study, we incubated in vitro cultures of B. bovis in an ice bath to liberate merozoites from infected RBCs and then evaluated the isolated merozoites in RBC invasion and invasion-inhibitions assays. The viability of the purified merozoites (72.4%) was significantly higher than that of merozoites isolated with high-voltage electroporation (48.5%). The viable merozoites prepared with the cold treatment also invaded uninfected bovine RBCs at a higher rate (0.572%) than did merozoites prepared with high-voltage electroporation (0.251%). The invasion-blocking capacities of heparin, a polyclonal rabbit antibody directed against recombinant B. bovis rhoptry associated protein 1, and B. bovis-infected bovine serum were successfully demonstrated in an RBC invasion assay with the live merozoites prepared with the cold treatment, suggesting that the targets of these inhibitors were intact in the merozoites. These findings indicate that the cold treatment technique is a useful tool for the isolation of free, viable, invasion-competent B. bovis merozoites, which can be effectively used for RBC invasion and invasion-inhibition assays in Babesia research.


Assuntos
Babesia bovis/fisiologia , Temperatura Baixa , Eritrócitos/parasitologia , Animais , Anticorpos Antiprotozoários/imunologia , Anticoagulantes/farmacologia , Babesia bovis/imunologia , Babesiose/parasitologia , Bovinos , Centrifugação com Gradiente de Concentração , Eletroporação , Feminino , Heparina/farmacologia , Merozoítos/fisiologia , Parasitemia/parasitologia , Coelhos
10.
Vet Res Commun ; 48(4): 2753-2760, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38676858

RESUMO

INTRODUCTION: Tick-borne diseases (TBDs) pose a major hindrance to livestock production in countries with limited resources. Effective prevention and management of TBDs require a thorough understanding of disease vectors and pathogens. However, there is limited information on studies of bovine tick-borne pathogens (TBPs) using molecular methods in Malawi. This study aimed to detect TBPs of cattle populations in southern Malawi, which has the largest cattle population in the country. METHODOLOGY: A total of 220 blood samples from apparently healthy cattle were collected in six districts, and were screened for selected TBPs using polymerase chain reaction (PCR). RESULTS: The overall detection rate of TBPs was 72.3%. Among the detected pathogens, Babesia bigemina had the highest detection rate (34.5%), followed by Anaplasma marginale (23.2%), Anaplasma phagocytophilum (22.3%), Theileria taurotragi (22.3%), Theileria parva (15.5%), Anaplasma bovis (9.6%), Babesia bovis (7.3%), Theileria mutans (4.1%), and Babesia naoakii (2.7%). Among the positive samples, 64.2% were found to be co-infected with two or more TBPs, with the highest number of seven pathogens detected in a single sample. The study documents the existence of A. phagocytophilum, B. bovis, and B. naoakii in Malawian cattle for the first time. CONCLUSION: The findings herein demonstrate a significant burden of TBPs on cattle in Malawi, which gives a challenge in combating TBDs. The high TBP burden, along with the high co-infection frequencies in Malawian cattle necessitates the urgency to implement effective control strategies to enhance cattle production in the country.


Assuntos
Babesia , Doenças dos Bovinos , Filogenia , Doenças Transmitidas por Carrapatos , Animais , Bovinos , Malaui/epidemiologia , Doenças Transmitidas por Carrapatos/veterinária , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/parasitologia , Doenças Transmitidas por Carrapatos/microbiologia , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/epidemiologia , Babesia/isolamento & purificação , Babesia/genética , Reação em Cadeia da Polimerase/veterinária , Babesiose/epidemiologia , Babesiose/parasitologia , Theileria/genética , Theileria/isolamento & purificação , Anaplasmose/epidemiologia , Anaplasmose/microbiologia , Anaplasma/genética , Anaplasma/isolamento & purificação
11.
PLoS One ; 19(4): e0302053, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38625961

RESUMO

Increased antimicrobial resistance (AMR) among bacteria underscores the need to strengthen AMR surveillance and promote data-based prescribing. To evaluate trends and associations between antimicrobial usage (AMU) and AMR, we explored a dataset of 34,672 bacterial isolates collected between 2015 and 2020 from clinical samples at the University Teaching Hospital (UTH) in Lusaka, Zambia. The most frequently isolated species were Escherichia coli (4,986/34,672; 14.4%), Staphylococcus aureus (3,941/34,672; 11.4%), and Klebsiella pneumoniae (3,796/34,672; 10.9%). Of the 16 drugs (eight classes) tested, only amikacin and imipenem showed good (> 50%) antimicrobial activity against both E. coli and K. pneumoniae, while nitrofurantoin was effective only in E. coli. Furthermore, 38.8% (1,934/4,980) of E. coli and 52.4% (2,079/3,791) of K. pneumoniae isolates displayed multidrug resistance (MDR) patterns on antimicrobial susceptibility tests. Among S. aureus isolates, 44.6% (973/2,181) were classified as methicillin-resistant (MRSA). Notably, all the MRSA exhibited MDR patterns. The annual hospital AMR rates varied over time, while there was a weak positive relationship (r = 0.38, 95% CI = 0.11-0.60) between the monthly use of third-generation cephalosporins (3GCs) and 3GC resistance among Enterobacterales. Overall, the results revealed high AMR rates that fluctuated over time, with a weak positive relationship between 3GC use and resistance. To our knowledge, this is the first report to evaluate the association between AMU and AMR in Zambia. Our results highlight the need to strengthen antimicrobial stewardship programs and optimize AMU in hospital settings.


Assuntos
Antibacterianos , Anti-Infecciosos , Humanos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Escherichia coli , Zâmbia/epidemiologia , Staphylococcus aureus , Farmacorresistência Bacteriana , Anti-Infecciosos/farmacologia , Hospitais , Klebsiella pneumoniae , Encaminhamento e Consulta , Testes de Sensibilidade Microbiana
12.
Exp Mol Pathol ; 94(1): 228-38, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22981919

RESUMO

Our efforts are concerned with identifying features of incomplete malignant transformation caused by non viral pathogens. Theileria parva (T. parva) is a tick-transmitted protozoan parasite that can cause a fatal lymphoproliferative disease in cattle. The T. parva-infected lymphocytes display a transformed phenotype and proliferate in culture media like the other tumor cells, however those cells will return to normal after antiprotozoal treatment reflecting the incomplete nature of transformation. To identify signaling pathways involved in this form of transformation of T. parva-infected cells, we screened a library of anticancer compounds. Among these, TIBC, a specific inhibitor of MDM2, markedly inhibited proliferation of T. parva-infected lymphocytes and promoted apoptosis. Therefore we analyzed MDM2 function in T. parva-infected cells. Several T. parva-infected cell lines showed increased expression level of MDM2 with alternatively spliced isoforms compared to the lymphoma cells or ConA blasts. In addition, buparvaquone affected MDM2 expression in T. parva transformed cells. Moreover, p53 protein accumulation and function were impaired in T. parva-infected cells after cisplatin induced DNA damage despite the increased p53 transcription level. Finally, the treatment of T. parva-infected cells with boronic-chalcone derivatives TIBC restored p53 protein accumulation and induced Bax expression. These results suggest that the overexpression of MDM2 is closely linked to the inhibition of p53-dependent apoptosis of T. parva-infected lymphocytes. Aberrant expression of host lymphocyte MDM2 induced by cytoplasmic existence of T. parva, directly and/or indirectly, is associated with aspects of this type of transformation of T. parva-infected lymphocytes. This form of transformation shares features of oncogene induced malignant phenotype acquisition.


Assuntos
Transformação Celular Neoplásica , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Linfócitos T/parasitologia , Theileria parva/patogenicidade , Proteína Supressora de Tumor p53/metabolismo , Sequência de Aminoácidos , Animais , Apoptose , Bovinos , Linhagem Celular , Cisplatino/farmacologia , Dano ao DNA/efeitos dos fármacos , Ativação Enzimática , Ativação Linfocitária , Dados de Sequência Molecular , NF-kappa B/metabolismo , Naftoquinonas/farmacologia , Isoformas de Proteínas , Proteínas Proto-Oncogênicas c-mdm2/genética , Transdução de Sinais , Linfócitos T/patologia , Theileria parva/imunologia , Proteína X Associada a bcl-2/biossíntese
13.
J Vet Diagn Invest ; 35(3): 307-310, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37029660

RESUMO

The lack of quick, accurate, and low-cost detection methods has hindered the active control strategies for bovine tuberculosis (bTB) in resource-limited countries with a high burden of disease. We developed a dry loop-mediated isothermal amplification (LAMP) assay for rapid and specific detection of Mycobacterium bovis, the principal causative agent of bTB, and evaluated the efficacy of the assay using suspected bTB samples collected during routine meat inspection at major regional abattoirs in Malawi. Template genomic DNA was extracted directly from the granulomatous bTB-like lesion (crude extracted DNA), as well as growth from the incubated mycobacterial growth indicator tubes (MGIT). Field results were visualized by the naked eye within 40 min following a color change of the amplified products. The sensitivity and specificity of the dry LAMP assay while using 152 DNA samples extracted from MGIT with confirmed M. bovis results were 98% and 88%, respectively. When 43 randomly selected crude DNA samples from lesions were used, the sensitivity and specificity of the dry LAMP assay were 100% and 75%, respectively. Our LAMP assay offers the potential to meet the demands for a low-cost and rapid field detection tool for bTB in resource-limited countries in which bTB is endemic.


Assuntos
Doenças dos Bovinos , Mycobacterium bovis , Tuberculose Bovina , Bovinos , Animais , Mycobacterium bovis/genética , Matadouros , Malaui , Técnicas de Amplificação de Ácido Nucleico/veterinária , Técnicas de Amplificação de Ácido Nucleico/métodos , Tuberculose Bovina/diagnóstico , Tuberculose Bovina/epidemiologia , DNA , Sensibilidade e Especificidade
14.
Microorganisms ; 11(10)2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37894242

RESUMO

Molecular assays and capillary electrophoresis sequencing have been used to identify parasites in livestock. The low sample capacity, which increases labor and processing time, is one drawback. Targeted amplicon sequencing (Ampliseq) uses the fast and large sample capacity platform to identify parasites in the target host, overcoming this limitation. DNA was extracted from 162 whole blood samples collected from cattle in three provinces in the Philippines. Using Illumina's Miseq platform, the V4 hypervariable region of the piroplasma 18S rRNA gene was amplified and sequenced. The AMPtk pipeline was used to obtain distinct amplicon sequence variants (ASVs) and the NCBI BLAST non-redundant database was used to assign taxonomy. In total, 95 (58.64%) samples were positive for piroplasma. Using the AMPTk pipeline, 2179 ASVs were obtained. A total of 79 distinct ASVs were obtained after clustering and filtering, which belonged to genera Babesia (n = 58), Theileria (n = 17), Hepatozoon (n = 2), and Sarcocystis (n = 2). The ASV top hits were composed of 10 species: Babesia bovis, B. bigemina, Theileria orientalis, Babesia sp., Hepatozoon canis, Sarcocystis cruzi, T. annulata, T. equi, T. mutans, and Theileria sp. Thung Song. The results generated in this study demonstrated the applicability of Ampliseq in detecting piroplasmid parasites infecting cattle in the Philippines.

15.
Microbiol Resour Announc ; 12(5): e0131822, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37074197

RESUMO

We report sequences of the complete linear chromosome and five linear plasmids of the relapsing fever spirochete "Candidatus Borrelia fainii" Qtaro. The chromosome sequence of 951,861 bp and the 243,291 bp of plasmid sequences were predicted to contain 852 and 239 protein-coding genes, respectively. The predicted total GC content was 28.4%.

16.
Heliyon ; 9(2): e13647, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36865451

RESUMO

Bovine tuberculosis (bTB) is an infectious disease with significant socioeconomic, animal, and public health impacts. However, the prevalence of bTB remains largely unclear in Malawi due to a paucity of information. Additionally, the existence of multiple risk factors is postulated to enhance bTB transmission in animals. A cross-sectional survey to estimate the prevalence of bTB, animal characteristics and identify associated risk factors was conducted from slaughtered cattle at three major regional abattoirs (southern, central and northern regions) in Malawi. Out of a total of 1547 cattle examined, 154 (9.95%) had bTB-like lesions in various visceral organs and lymph nodes; one sample per animal was collected, processed, and cultured in the in the BACTEC Mycobacterial growth indicator tube (MGIT) 960 system. From the 154 cattle that showed tuberculous like lesions, only 112 were positive on MGIT and 87 were confirmed to have M. bovis based on multiplex PCR. Cattle from the southern region (odds ratio (OR) = 1.96, 95% CI: 1.03-3.85) and central region (OR = 2.00, 95% CI: 1.16-3.56) were more likely presented with bTB-like lesions at slaughter than from the northern region. The risk of having bTB-like lesions was higher in females (OR = 1.51, CI: 1.00-2.29), older cattle (OR = 2.17, CI: 1.34-3.37), and crossbreeds (OR = 1.67, 95% CI: 1.12-2.47) than in males, younger animals, and Malawi Zebu breed, respectively. The high prevalence of bTB is of critical concern and necessitates active surveillance and strengthening of the current control strategies under a One Health (OH) approach at the animal-human interface.

17.
PLoS One ; 18(5): e0285861, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37192155

RESUMO

A novel multiplex loop-mediated isothermal amplification (LAMP) method combined with DNA chromatography was developed for the simultaneous detection of three important respiratory disease-causing viruses: severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus, and influenza B virus. Amplification was performed at a constant temperature, and a positive result was confirmed by a visible colored band. An in-house drying protocol with trehalose was used to prepare the dried format multiplex LAMP test. Using this dried multiplex LAMP test, the analytical sensitivity was determined to be 100 copies for each viral target and 100-1000 copies for the simultaneous detection of mixed targets. The multiplex LAMP system was validated using clinical COVID-19 specimens and compared with the real-time qRT-PCR method as a reference test. The determined sensitivity of the multiplex LAMP system for SARS-CoV-2 was 71% (95% CI: 0.62-0.79) for cycle threshold (Ct) ≤ 35 samples and 61% (95% CI: 0.53-0.69) for Ct ≤40 samples. The specificity was 99% (95%CI: 0.92-1.00) for Ct ≤35 samples and 100% (95%CI: 0.92-1.00) for the Ct ≤40 samples. The developed simple, rapid, low-cost, and laboratory-free multiplex LAMP system for the two major important respiratory viral diseases, COVID-19 and influenza, is a promising field-deployable diagnosis tool for the possible future 'twindemic, ' especially in resource-limited settings.


Assuntos
COVID-19 , Orthomyxoviridae , Humanos , SARS-CoV-2/genética , COVID-19/diagnóstico , Sensibilidade e Especificidade , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , DNA , RNA Viral/análise
18.
Front Cell Infect Microbiol ; 12: 848693, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35372115

RESUMO

Toxoplasma gondii bradyzoites establish chronic infections within their host cells. Recent studies have demonstrated that several parasite effector proteins are translocated to host cells during the bradyzoite stage of chronic infection. To understand the interaction between host cells and bradyzoites at the transcriptomic landscape level, we utilized single-cell RNA-sequencing (scRNA-Seq) to characterize the bradyzoite-induced host cell response. Distinct gene expression profiles were observed in infected host, cells with low parasite mapped reads, and mock (non-exposed) control cells. Gene set enrichment analysis showed that c-Myc and NF-κB signaling and energy metabolic pathways were upregulated by infection. Type I and II interferon response pathways were upregulated in cells with low parasite mapped reads compared to the non-exposed host control cells, and this upregulation effect was reversed in infected cells. Differences were observed in the host cells depending on the differentiation status of the parasites, as determined by BAG1 and SAG1 expression. NF-κB, inflammatory response pathways, and IFN-γ response pathways were downregulated in host cells containing T. gondiiBAG1+/SAG1-, whereas this downregulation effect was reversed in case of T. gondiiBAG1-/SAG1+. We also identified two distinct host cell subsets that contained T. gondiiBAG1+/SAG1-, one of which displayed distinct transcriptomes with upregulated c-Myc expression. Overall, these data clearly demonstrate that host cell transcriptional alteration by bradyzoite infection is different from that of tachyzoite infection, indicating fine-tuning of the host immune response.


Assuntos
Toxoplasma , Diferenciação Celular , Regulação para Baixo , Toxoplasma/metabolismo , Transcriptoma , Regulação para Cima
19.
Interdiscip Perspect Infect Dis ; 2022: 2109641, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36212105

RESUMO

With an increasing number of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) sequences gathered worldwide, we recognize that deletion mutants and nucleotide substitutions that may affect whole-genome sequencing are accumulating. Here, we propose an additional strategy for tiling PCR for whole-genome resequencing, which can make the pipeline robust for mutations at the primer annealing site by a redundant amplicon scheme. We further demonstrated that subtracting overrepresented amplicons from the multiplex PCR products reduced the bias of the next-generation sequencing (NGS) library, resulting in decreasing required sequencing reads per sample. We applied this sequencing strategy to clinical specimens collected in Bangladesh. More than 80% out of the 304 samples were successfully sequenced. Less than 5% were ambiguous nucleotides, and several known variants were detected. With the additional strategies presented here, we believe that whole-genome resequencing of SARS-CoV-2 from clinical samples can be optimized.

20.
Infect Genet Evol ; 98: 105213, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35041968

RESUMO

Toxoplasma gondii is one of the most common zoonotic protozoan parasites. It has three major infectious stages: rapidly multiplying tachyzoites (Tz), slowly replicating bradyzoites (Bz) and a resting/free-living stage, sporozoites (Sz). The regulatory mechanisms governing stage-specific gene expression are not fully understood. Few transcriptional start sites (TSS) are known for Sz. In this study, we obtained TSS of Sz using an oligo-capping method and RNA-seq analysis. We identified 1,043,503 TSS in the Sz transcriptome. These defined 38,973 TSS clusters, of which, 11,925 were expressed in Sz and 1535 TSS differentially expressed in Sz. Based on these data, we defined promoter regions and novel sporozoite stage-specific motifs using MEME. TGTANNTACA was distributed around -55 to -75 regions from each TSS. Interestingly, the same motif was reported in another apicomplexan, Plasmodium berghei, as a cis-element of female-specific gametocyte genes, implying the presence of common regulatory machinery. Further comparative analysis should better define the distribution and function of these elements in other members of this important parasitic phylum.


Assuntos
Regiões Promotoras Genéticas , Esporozoítos/genética , Toxoplasma/genética , Sítio de Iniciação de Transcrição , RNA-Seq
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