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Rabies persists as a longstanding issue in Zambia, despite being preventable. The current control measures, including dog vaccination, population control, and movement restriction, guided by 'The Control of Dogs Act Chapter 247 of the Laws of Zambia', have not yielded the desired impact in many areas of the country including Manyinga and Mwansabombwe districts. These two districts continue to report low dog vaccination rates, unrestricted dog movements, and escalating cases of animal and human rabies, along with dog bites. Aligned with global aspirations to achieve zero human rabies cases by 2030, this study scrutinizes the determinants and obstacles hampering the execution of rabies control initiatives in Manyinga and Mwansabombwe. Spanning approximately 11 months, this cross-sectional study gathered pre- and post-vaccination data from 301 households in Manyinga and 100 households in Mwansabombwe. Questionnaires probed knowledge, attitudes, and practices related to rabies prevention and control. A transect survey, key informant interviews, and assessment of rabies vaccination and dog bite records complemented the data collection. Findings revealed that 88.0% of respondents from both districts possessed knowledge about rabies, confirming affected species and transmission. Moreover, 76.8% in Manyinga and 88.6% in Mwansabombwe were acquainted with rabies prevention and control methods. Concerning dog owners, 89.0% were aware of rabies, 66.0% understood its prevention and control, and the majority identified bites as the primary mode of transmission. Despite the high level of knowledge recorded during the survey, the implementation of preventive measures was low, which was attributed to low levels of law enforcement by the local government authority, inadequate staffing in the veterinary department, unwillingness to pay for dog vaccinations, and unavailability of rabies vaccine at the veterinary office in both districts. Vaccination coverage stood at 64.0% in Manyinga and 21.0% in Mwansabombwe. Notably, education and occupation exhibited a positive significant association with rabies knowledge. In terms of dog bite cases, Manyinga recorded 538 dog bite cases from 2017 to June 2022, while Mwansabombwe recorded 81 dog bite and 23 jackal bite cases from 2021 to June 2022. The study underscores critical knowledge gaps in rural areas and emphasizes the imperative for enhanced public education and awareness programs, improved rabies surveillance, free mass vaccination campaigns, and community engagement to augment vaccination coverage and knowledge about rabies.
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Enteric infections due to viral pathogens are a major public health concern. Detecting the risk areas requires a strong surveillance system for pathogenic viruses in sources such as wastewater. Towards building an environmental surveillance system in Zambia, we aimed to identify group A rotavirus (RVA) and human adenovirus (HAdV) in wastewater. Convenient sampling was conducted at four study sites every Tuesday for five consecutive weeks. The research team focused on three different methods of viral concentration to determine the suitability in terms of cost and applicability for a regular surveillance system: the bag-mediated filtration system (BMFS), polyethylene glycol-based (PEG) precipitation, and skimmed milk (SM) flocculation. We screened 20 wastewater samples for HAdV and RVA using quantitative polymerase chain reaction (qPCR) and conventional polymerase chain reaction (cPCR). Of the 20 samples tested using qPCR, 18/20 (90%) tested positive for HAdV and 14/20 (70%) tested positive for RVA. For the genetic sequencing, qPCR positives were subjected to cPCR, of which 12 positives were successfully amplified. The human adenovirus was identified with a nucleotide identity range of 98.48% to 99.53% compared with the reference genome from GenBank. The BMFS and SM flocculation were the most consistent viral concentration methods for HAdV and RVA, respectively. A statistical analysis of the positives showed that viral positivity differed by site (p < 0.001). SM and PEG may be the most appropriate options in resource-limited settings such as Zambia due to the lower costs associated with these concentration methods. The demonstration of HAdV and RVA detection in wastewater suggests the presence of the pathogens in the communities under study and the need to establish a routine wastewater surveillance system for the identification of pathogens.
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Antimicrobial resistance (AMR) among Escherichia coli from food animals is a rising problem, and heavy antimicrobial use in poultry is a contributing factor. In Zambia, studies linking poultry-associated AMR and antibiotic use (AMU) are rare. This study aimed to investigate commercial and medium-/small-scale poultry farmers' usage of antimicrobials based on a questionnaire survey in ten districts of Zambia. In addition, the study characterized extended-spectrum ß-lactamase (ESBL)-producing E. coli isolates obtained from poultry in the same districts. Data regarding knowledge and usage of antimicrobials were collected from commercial and medium-/small-scale poultry farmers using a pre-tested structured questionnaire. At the same time, cloacal samples were collected and analyzed. One hundred and fifty E. coli isolates were tested for antimicrobial susceptibility using eight antibiotic classes. The isolates were further screened for ESBL production by streaking them on cefotaxime (CTX)-supplemented MacConkey agar, then subjecting them to sequencing on a NextSeq. The questionnaire survey showed that more medium-/small-scale than commercial poultry farmers used antimicrobials (OR = 7.70, 95% CI = 2.88-20.61) but less prescriptions (OR = 0.02, 95% CI = 0.00-0.08). Susceptibility testing revealed that resistance was highest to ampicillin (128/148, 86.5%) and tetracycline (101/136, 74.3%) and that the prevalence of multidrug resistance (MDR) (28/30, 93.3%) was high. Whole-genome sequencing (WGS) of eight (8/30, 26.7%) isolates with CTX Minimum Inhibitory Concentration (MIC) ≥ 4 µg/mL revealed the presence of ESBL-encoding genes blaCTX-M-14, blaCTX-M-55, and blaTEM. WGS also detected other AMR genes for quinolones, aminoglycosides, phenicols, tetracycline, macrolides, and folate-pathway antagonists. Altogether, the questionnaire survey results showed a higher proportion of AMU and lower prescription usage among medium-/small-scale farmers. In addition, our results emphasize the circulation of ESBL-producing E. coli strains with associated MDR. It is critical to educate farmers about AMR risks and to encourage responsible usage of antimicrobials. Furthermore, there is a need to strengthen regulations limiting access to antimicrobials. Finally, there is a need to establish a one health system to guide public health response.
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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.
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Antibacterianos , Antiinfecciosos , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Escherichia coli , Zambia/epidemiología , Staphylococcus aureus , Farmacorresistencia Bacteriana , Antiinfecciosos/farmacología , Hospitales , Klebsiella pneumoniae , Derivación y Consulta , Pruebas de Sensibilidad MicrobianaRESUMEN
Poultry products in Zambia form an integral part of the human diet in many households, as they are cheap and easy to produce. The burden of poultry diseases has, however, remained a major challenge. Growing consumer demand for poultry products in Zambia has resulted in non-prudent antimicrobial use on farms, intending to prevent and treat poultry diseases for growth optimisation and maximising profits. This cross-sectional study aimed to identify the different types of bacteria causing diseases in chickens in Lusaka and to detect the extended-spectrum lactamase (ESBL)-encoding genes. We collected 215 samples from 91 diseased chickens at three post-mortem facilities and screened them for Gram-negative bacteria. Of these samples, 103 tested positive for various clinically relevant Enterobacteriaceae, including Enterobacter (43/103, 41.7%), Escherichia coli (20/103, 19.4%), Salmonella (10/103, 9.7%), and Shigella (8/103, 7.8%). Other isolated bacteria included Yersinia, Morganella, Proteus, and Klebsiella, which accounted for 21.4%. E. coli, Enterobacter, Salmonella, and Shigella were subjected to antimicrobial susceptibility testing. The results revealed that E. coli, Enterobacter, and Shigella were highly resistant to tetracycline, ampicillin, amoxicillin, and trimethoprim-sulfamethoxazole, while Salmonella showed complete susceptibility to all tested antibiotics. The observed resistance patterns correlated with antimicrobial usage estimated from sales data from a large-scale wholesale and retail company. Six (6/14, 42.9%) E. coli isolates tested positive for blaCTX-M, whilst eight (8/14, 57.1%) Enterobacter samples tested positive for blaTEM. Interestingly, four (4/6, 66.7%) of the E. coli isolates carrying blaCTX-M-positive strains were also positive for blaTEM. Sanger sequencing of the PCR products revealed that five (5/6, 83.3%) of the abovementioned isolates possessed the blaCTX-M-15 allele. The results suggest the presence of potentially pathogenic ESBL-producing Enterobacteriaceae in poultry, threatening public health.
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Mosquitoes interact with various organisms in the environment, and female mosquitoes in particular serve as vectors that directly transmit a number of microorganisms to humans and animals by blood-sucking. Comprehensive analysis of mosquito-borne viruses has led to the understanding of the existence of diverse viral species and to the identification of zoonotic arboviruses responsible for significant outbreaks and epidemics. In the present study on mosquito-borne bunyaviruses we employed a broad-spectrum RT-PCR approach and identified eighteen different additional species in the Phenuiviridae family and also a number of related but unclassified bunyaviruses in mosquitoes collected in Zambia. The entire RNA genome segments of the newly identified viruses were further analyzed by RNA sequencing with a ribonuclease R (RNase R) treatment to reduce host-derived RNAs and enrich viral RNAs, taking advantage of the dsRNA panhandle structure of the bunyavirus genome. All three or four genome segments were identified in eight bunyavirus species. Furthermore, L segments of three different novel viruses related to the Leishbunyaviridae were found in mosquitoes together with genes from the suspected host, the Crithidia parasite. In summary, our virus detection approach using a combination of broad-spectrum RT-PCR and RNA sequencing analysis with a simple virus enrichment method allowed the discovery of novel bunyaviruses. The diversity of bunyaviruses is still expanding and studies on this will allow a better understanding of the ecology of hematophagous mosquitoes.
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Arbovirus , Culicidae , Orthobunyavirus , Virus ARN , Animales , Humanos , Femenino , Mosquitos Vectores , Orthobunyavirus/genética , Virus ARN/genética , Arbovirus/genéticaRESUMEN
Background and Aim: Inappropriate use of antimicrobials exacerbates antimicrobial resistance (AMR) in the poultry sector. Information on factors driving AMR in the layer poultry sector is scarce in Zambia. This study examined the drivers of AMR in the layer poultry sector in the Lusaka and Copperbelt Provinces of Zambia. Materials and Methods: This cross-sectional study employed a structured questionnaire in 77 layer poultry farms in the provinces of Lusaka and Copperbelt, Zambia, from September 2020 to April 2021. Data analysis was conducted using Stata version 16.1. Antimicrobial resistance was defined as the presence of multidrug resistance (MDR) isolates. Multivariable regression analysis was used to identify drivers of AMR. Results: In total, 365 samples were collected, from which 339 (92.9%) Escherichia coli and 308 (84.4%) Enterococcus spp. were isolated. Multidrug resistance was identified in 39% of the E. coli and 86% of the Enterococcus spp. The overall prevalence of AMR in layer poultry farms was 51.7% (95% confidence interval [CI]: 40.3%-63.5%). Large-scale farmers (Adjusted odds ratio [AOR] = 0.20, 95% CI: 0.04%-0.99%) than small-scale and farmers who were aware of AMR than those who were unaware (AOR = 0.26, 95% CI: 0.08%-0.86%) were less likely to experience AMR problems. Conclusion: This study found a high prevalence of AMR in layer poultry farming linked to the type of farm management practices and lack of AMR awareness. Evidence of high MDR in our study is of public health concern and requires urgent attention. Educational interventions must increase AMR awareness, especially among small- and medium-scale poultry farmers.
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West Nile virus (WNV) causes encephalitis in human and animals. WNV is phylogenetically classified into at least five distinct genetic lineages with different pathogenicity. The pathogenesis of West Nile encephalitis is affected by ubiquitin accumulation in infected cells, but the mechanism is unknown. In this study, the association between ubiquitin accumulation and WNV pathogenicity was investigated. Ubiquitin accumulation was detected in cells infected with NY99 strain belonging to lineage-1, but not FCG and Zmq16 strains belonging to lineage-2. Substitution of the Finger and Palm sub-domains of NS5 from lineage-1 to -2 decreased ubiquitin accumulation and viral replication. Furthermore, the survival rate was increased, and viral replication and ubiquitin accumulation in the brain were attenuated, in mice inoculated with the substituted WNV compared with lineage-1 WNV. Therefore, the intracellular ubiquitin accumulation induced by the Finger and Palm sub-domains of NS5 is linked to the differences in pathogenicity among WNV lineages.
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Fiebre del Nilo Occidental , Virus del Nilo Occidental , Humanos , Animales , Ratones , Virus del Nilo Occidental/genética , Ubiquitina , Encéfalo , Replicación Viral/genéticaRESUMEN
The emergence of pre-extensively drug-resistant tuberculosis (pre-XDR-TB) is a threat to TB control programs in developing countries such as Zambia. Studies in Zambia have applied molecular techniques to understand drug-resistance-associated mutations, circulating lineages and transmission patterns of multi-drug-resistant (MDR) Mycobacterium tuberculosis. However, none has reported genotypes and mutations associated with pre-XDR TB. This study characterized 63 drug-resistant M. tuberculosis strains from the University Teaching Hospital between 2018 and 2019 using targeted gene sequencing and conveniently selected 50 strains for whole genome sequencing. Sixty strains had resistance mutations associated to MDR, one polyresistant, and two rifampicin resistant. Among MDR strains, seven percent (4/60) had mutations associated with pre-XDR-TB. While four, one and nine strains had mutations associated with ethionamide, para-amino-salicylic acid and streptomycin resistances, respectively. All 50 strains belonged to lineage 4 with the predominant sub-lineage 4.3.4.2.1 (38%). Three of four pre-XDR strains belonged to sub-lineage 4.3.4.2.1. Sub-lineage 4.3.4.2.1 strains were less clustered when compared to sub-lineages L4.9.1 and L4.3.4.1 based on single nucleotide polymorphism differences. The finding that resistances to second-line drugs have emerged among MDR-TB is a threat to TB control. Hence, the study recommends a strengthened routine drug susceptibility testing for second-line TB drugs to stop the progression of pre-XDR to XDR-TB and improve patient treatment outcomes.
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Zambia has seen rapid development in aquaculture, and in recent years, the industry has experienced disease outbreaks where fish have increasingly become a potential contributor to emerging bacterial zoonotic diseases. The aim of this study was to identify bacterial pathogens with zoonotic potential in apparently healthy fish and water from their habitat. A total of sixty-three fish were sampled, and fifty-nine water samples were collected from the habitats of these fish. Bacteria were cultured from the internal organs of fish and water, and these were identified through standard bacteriological methods comprising morphological characterization, Gram-staining, and a panel of biochemical tests. The following bacterial pathogens with zoonotic potential were identified at a farm prevalence of Aeromonas (13.2%), Bacillus (2.1%), Clostridium (2.1%), Escherichia coli (0.7%), Klebsiella (6.9%), Lactococcus (2.1%), Listeria (0.7%), Staphylococcus (18.1%), and Streptococcus (0.7). Other bacteria with varying significance as fish pathogens identified included Acinetobacter (2.1%), Aequorivita (1.4%), Aerococcus (1.4%), Bordetella (2.1%), Carnobacterium (10.4%), Citrobacter (3.5%), Corynebacterium (1.4%), Dermatophilus (1.4%), Enterococcus (2.1%), Flavobacterium (4.2%), Micrococcus (6.9%), Planococcus (1.4%), Proteus (1.4%), Pseudomonas (6.3%), Rhodococcus (1.4%), Shewanella (1.4%), Streptococcus (0.7%), and Vagococcus (0.7%). The current study provides baseline information for future reference and the implementation of public health guidelines with regard to potential zoonotic diseases in fish.
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Bats are of significant interest as reservoirs for various zoonotic viruses with high diversity. During the past two decades, many herpesviruses have been identified in various bats worldwide by genetic approaches, whereas there have been few reports on the isolation of infectious herpesviruses. Herein, we report the prevalence of herpesvirus infection of bats captured in Zambia and genetic characterization of novel gammaherpesviruses isolated from striped leaf-nosed bats (Macronycteris vittatus). By our PCR screening, herpesvirus DNA polymerase (DPOL) genes were detected in 29.2% (7/24) of Egyptian fruit bats (Rousettus aegyptiacus), 78.1% (82/105) of Macronycteris vittatus, and one Sundevall's roundleaf bat (Hipposideros caffer) in Zambia. Phylogenetic analyses of the detected partial DPOL genes revealed that the Zambian bat herpesviruses were divided into seven betaherpesvirus groups and five gammaherpesvirus groups. Two infectious strains of a novel gammaherpesvirus, tentatively named Macronycteris gammaherpesvirus 1 (MaGHV1), were successfully isolated from Macronycteris vittatus bats, and their complete genomes were sequenced. The genome of MaGHV1 encoded 79 open reading frames, and phylogenic analyses of the DNA polymerase and glycoprotein B demonstrated that MaGHV1 formed an independent lineage sharing a common origin with other bat-derived gammaherpesviruses. Our findings provide new information regarding the genetic diversity of herpesviruses maintained in African bats.
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Quirópteros , Gammaherpesvirinae , Herpesviridae , Animales , Filogenia , Zambia/epidemiología , Herpesviridae/genéticaRESUMEN
The presence of antimicrobial-resistant Enterococci in poultry is a growing public health concern worldwide due to its potential for transmission to humans. The aim of this study was to determine the prevalence and patterns of antimicrobial resistance and to detect drug-resistant genes in Enterococcus faecalis and E. faecium in poultry from four districts in Zambia. Identification of Enterococci was conducted using phenotypic methods. Antimicrobial resistance was determined using the disc diffusion method and antimicrobial resistance genes were detected using polymerase chain reaction and gene-specific primers. The overall prevalence of Enterococci was 31.1% (153/492, 95% CI: 27.1-35.4). Enterococcus faecalis had a significantly higher prevalence at 37.9% (58/153, 95% CI: 30.3-46.1) compared with E. faecium, which had a prevalence of 10.5% (16/153, 95% CI: 6.3-16.7). Most of the E. faecalis and E. faecium isolates were resistant to tetracycline (66/74, 89.2%) and ampicillin and erythromycin (51/74, 68.9%). The majority of isolates were susceptible to vancomycin (72/74, 97.3%). The results show that poultry are a potential source of multidrug-resistant E. faecalis and E. faecium strains, which can be transmitted to humans. Resistance genes in the Enterococcus species can also be transmitted to pathogenic bacteria if they colonize the same poultry, thus threatening the safety of poultry production, leading to significant public health concerns.
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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%.
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Slaughterhouses in South Sudan mirror the economic losses resulting from cattle organs and carcass condemnation due to zoonotic and epizootic diseases of livestock, such as tuberculosis, cysticercosis, and hydatidosis in cattle. However, due to the war, slaughterhouse record keeping has been inconsistent in South Sudan, and thus the estimation of diseases in cattle and their impact may be underestimated. Therefore, this study was conducted to estimate the major causes of carcasses and organ condemnation of cattle slaughtered at Lokoloko abattoir and the resulting financial losses. A cross-sectional active abattoir survey involving antemortem and postmortem examinations was conducted on 310 cattle between January 2021 and March 2021. Furthermore, five-year (September 2015-September 2020) retrospective data on meat inspection records were also collected and analyzed. During the antemortem inspection of the active abattoir survey, 103 (33.2%) cattle had signs of disease. These signs included herniam 17 (5.5%), local swelling 16 (5.2%), lameness 15 (4.8%), emaciation 13 (4.2%), blindness 12 (3.9%), depression 11 (3.5%), pale mucus membrane 7 (2.3%), nasal discharge 5 (1.6%), lacrimation 4 (1.3%), and salivation 03 (0.97%). Postmortem inspection revealed gross pathological findings on 180 (58.6%) carcasses, out of which 47 (26.1%) livers and 31 (17.2%) hearts were condemned due to various causes. The active abattoir survey and the retrospective data revealed that tuberculosis, fascioliasis, hydatidosis, and heart cysticercosis were the leading causes of condemnation of carcasses and organs. In the active abattoir survey, a total of 19,592,508 South Sudanese Pounds, equivalent to US$29,686 was lost from organ condemnation, while in the retrospective data; the overall direct financial loss during the five years was estimated to be 299,225,807 South Sudanese Pounds equivalent to US$453,372. This study revealed that bacterial and parasitic diseases were the common causes of carcass and organ condemnations and caused significant financial losses at Lokoloko abattoir in Wau, South Sudan. Therefore, there is a need for training farmers on cattle disease management, heightened meat inspections, and proper disposal of condemned meat.
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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.
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Rotavirus A (RVA) causes diarrheal disease in humans and various animals. Recent studies have identified bat and rodent RVAs with evidence of zoonotic transmission and genome reassortment. However, the virological properties of bat and rodent RVAs with currently identified genotypes still need to be better clarified. Here, we performed virus isolation-based screening for RVA in animal specimens and isolated RVAs (representative strains: 16-06 and MpR12) from Egyptian fruit bat and Natal multimammate mouse collected in Zambia. Whole-genome sequencing and phylogenetic analysis revealed that the genotypes of bat RVA 16-06 were identical to that of RVA BATp39 strain from the Kenyan fruit bat, which has not yet been characterized. Moreover, all segments of rodent RVA MpR12 were highly divergent and assigned to novel genotypes, but RVA MpR12 was phylogenetically closer to bat RVAs than to other rodent RVAs, indicating a unique evolutionary history. We further investigated the virological properties of the isolated RVAs. In brief, we found that 16-06 entered cells by binding to sialic acids on the cell surface, while MpR12 entered in a sialic acid-independent manner. Experimental inoculation of suckling mice with 16-06 and MpR12 revealed that these RVAs are causative agents of diarrhea. Moreover, 16-06 and MpR12 demonstrated an ability to infect and replicate in a 3D-reconstructed primary human intestinal epithelium with comparable efficiency to the human RVA. Taken together, our results detail the unique genetic and virological features of bat and rodent RVAs and demonstrate the need for further investigation of their zoonotic potential. IMPORTANCE Recent advances in nucleotide sequence detection methods have enabled the detection of RVA genomes from various animals. These studies have discovered multiple divergent RVAs and have resulted in proposals for the genetic classification of novel genotypes. However, most of these RVAs have been identified via dsRNA viral genomes and not from infectious viruses, and their virological properties, such as cell/host tropisms, transmissibility, and pathogenicity, are unclear and remain to be clarified. Here, we successfully isolated RVAs with novel genome constellations from three bats and one rodent in Zambia. In addition to whole-genome sequencing, the isolated RVAs were characterized by glycan-binding affinity, pathogenicity in mice, and infectivity to the human gut using a 3D culture of primary intestinal epithelium. Our study reveals the first virological properties of bat and rodent RVAs with high genetic diversity and unique evolutional history and provides basic knowledge to begin estimating the potential of zoonotic transmission.
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Quirópteros , Murinae , Infecciones por Rotavirus , Rotavirus , Animales , Quirópteros/virología , Diarrea/veterinaria , Diarrea/virología , Genoma Viral , Genotipo , Kenia , Filogenia , Rotavirus/genética , Rotavirus/aislamiento & purificación , Infecciones por Rotavirus/veterinaria , Murinae/virologíaRESUMEN
Relapsing fever (RF) is an arthropod-borne disease caused by Borrelia spirochete, which is one of the major public health concerns in endemic regions including Africa. However, information on Borrelia spirochetes is limited in Zambia. Here, we investigate the Borrelia spirochetes harbored by Ornithodoros ticks in Zambian National Parks. We analyzed 182 DNA samples pooled from 886 Ornithodoros ticks. Of these, 43 tested positive, and their sequence revealed that the ticks harbored both Old and New World RF borreliae. This research presents the first evidence of Old-World RF borreliae in Zambia. The New World RF borreliae detected herein differed from the Candidatus Borrelia fainii previously reported in Zambia and were closely related to the pathogenic Borrelia sp. VS4 identified in Tanzania. Additionally, Borrelia theileri was recently reported in Zambia. Hence, at least four different Borrelia species occur in Zambia, and the organisms causing relapsing fever there might be more complex than previously thought. We empirically confirmed that real-time PCR with TaqMan minor groove binder probes accurately and simultaneously detected both Old and New World RF. In this manner, they could facilitate quantitative analyses of both types of RF borreliae. Subsequent investigations should endeavor to isolate the aforementioned Borrelia spp. and perform serosurveys on patients with RF.
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A three-year study investigated the epidemiology of epizootic ulcerative syndrome (EUS) in fish from Kavango-Zambezi (KAZA) and Great Limpopo (GL) transfrontier conservation areas of Zimbabwe. A total of 38 sites comprising 27 wild fisheries and 11 aquacultures, from Mashonaland West, Matabeleland North and South, and Midlands were selected. Of the 27 wild fisheries, EUS-positive fish were detected from 9 (33.3%) and none from the 11 aquacultures. No positive cases were detected from Nile tilapia (Oreochromis niloticus) from both aquacultures and wild fisheries. A total of 9.9% (239/2423) fish from the nine positive fisheries had typical EUS lesions, and infection was confirmed in 15 species. Prevalence was significantly higher (p < 0.05) in KAZA (11.5%; 95% CI: 9.6-13.4) compared with GL (8.6%; 95% CI: 7.1-10.1). The most affected were Clarias, followed by Barbus and Oreochromis species. Most cases (>80%) were reported in winter when ambient temperature was low. Further studies are required to determine water parameters associated with EUS outbreaks. These results suggested that the African sharptooth catfish (Clarias gariepinus) could be used potentially as an indicator species for EUS surveillance programmes. Thus, implementation of surveillance and biosecurity programmes that take into consideration the epidemiology of EUS will be beneficial.
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Aphanomyces , Bagres , Cíclidos , Cyprinidae , Enfermedades de los Peces , Animales , Zimbabwe , Enfermedades de los Peces/epidemiología , Úlcera , AguaRESUMEN
Rapid, accurate and reliable assays are required for timely detection of drug-resistant tuberculosis and early initiation of second-line TB treatment as well as to minimize transmission of resistant strains. This study assessed diagnostic performance characteristics of two rapid molecular assays, line probe assay (LPA) and GeneXpert (MTB/RIF), in the detection rifampicin monoresistance using the phenotypic proportion method on Lowenstein−Jensen media as the gold standard. This study involved a total of 357 isolates, 74 rifampicin-resistant and 283 rifampicin-susceptible, collected at the Central Tuberculosis Reference Laboratory (CTRL) in Dar es Salaam, Tanzania, between 2016 and 2019. Sensitivity, specificity and positive and negative predictive values were used to assess the performance characteristics of the two assays while kappa coefficient was used to determine agreement of test results. The receiver operating curve (ROC) was used to determine the discriminatory ability of the test in distinguishing resistant and susceptible TB isolates. Our results showed that GeneXpert had sensitivity, specificity and positive and negative predictive values of 93.2, 82.7, 58.5 and 97.9%, respectively; the corresponding performance for LPA was 86.5, 97.5, 90.1 and 96.5%, respectively. Compared with conventional phenotypic DST results, GeneXpert had a moderate agreement (kappa 0.621, p < 0.001), while LPA had high agreement (0.853, p < 0.001). LPA showed an accuracy of 95.2% compared to GeneXpert's 84.9%. ROC curve depicted the ability of the tests to distinguish rifampicin-sensitive and rifampicin-resistant strains to be 87.9% for GeneXpert and 92.0% for LPA. Our results indicate the superiority of LPA over GeneXpert regarding detection of rifampicin monoresistance. However, logistic challenges such as longer turnaround time and need for skilled laboratory personnel may limit its use.
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Increased antimicrobial resistance (AMR) has been reported for pathogenic and commensal Escherichia coli (E. coli), hampering the treatment, and increasing the burden of infectious diarrhoeal diseases in children in developing countries. This study focused on exploring the occurrence, patterns, and possible drivers of AMR E. coli isolated from children under-five years in Zambia. A hospital-based cross-sectional study was conducted in the Lusaka and Ndola districts. Rectal swabs were collected from 565 and 455 diarrhoeic and healthy children, respectively, from which 1020 E. coli were cultured and subjected to antibiotic susceptibility testing. Nearly all E. coli (96.9%) were resistant to at least one antimicrobial agent tested. Further, 700 isolates were Multi-Drug Resistant, 136 were possibly Extensively-Drug Resistant and nine were Pan-Drug-Resistant. Forty percent of the isolates were imipenem-resistant, mostly from healthy children. A questionnaire survey documented a complex pattern of associations between and within the subgroups of the levels of MDR and socio-demographic characteristics, antibiotic stewardship, and guardians' knowledge of AMR. This study has revealed the severity of AMR in children and the need for a community-specific-risk-based approach to implementing measures to curb the problem.