Genetic diversity and population genetics of Schistosoma haematobium isolated from children in Lusaka and Siavonga districts, Zambia.

Urogenital schistosomiasis remains a pervasive health challenge in rural Zambian communities. This study explores the molecular epidemiology and genetic diversity of Schistosoma haematobium using mitochondrial genes (cox1 and nadh1). Urine samples from 421 children in Siavonga and Lusaka districts, Zambia, were collected between December 2020 and February 2022. Microscopy and DNA extraction facilitated the identification of S. haematobium, followed by amplification, sequencing, and phylogenetic analysis of cox1 and nadh1 genes. Phylogenetic analysis revealed clustering with samples from mainland African countries, emphasizing shared haplotypes. Both mitochondrial genes exhibited substantial diversity, with 5 haplotypes from 37 cox1 sequences and 12 haplotypes from 23 nadh1 sequences. High haplotype diversity (0.621-0.808) and low nucleotide diversity (0.00181-0.03288) were observed. Siavonga and Lusaka districts shared the majority of S. haematobium haplotypes. Molecular variance and genetic differentiation analysis indicated variations within populations rather than between populations (cox1: -0.025, nadh1: 0.01646). These findings suggest a limited differentiation between S. haematobium populations in Siavonga and Lusaka, potentially indicating gene flow. Tajima's test revealed negative values, indicating a departure from neutrality, introduction of rare alleles, and recent population expansion. This study contributes essential insights into S. haematobium population genetics, crucial for effective urogenital schistosomiasis control in Zambia.

Wastewater Surveillance of SARS-CoV-2 in Zambia: An Early Warning Tool.

Wastewater-based surveillance has emerged as an important method for monitoring the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This study investigated the presence of SARS-CoV-2 in wastewater in Zambia. We conducted a longitudinal study in the Copperbelt and Eastern provinces of Zambia from October 2023 to December 2023 during which 155 wastewater samples were collected. The samples were subjected to three different concentration methods, namely bag-mediated filtration, skimmed milk flocculation, and polythene glycol-based concentration assays. Molecular detection of SARS-CoV-2 nucleic acid was conducted using real-time Polymerase Chain Reaction (PCR). Whole genome sequencing was conducted using Illumina COVIDSEQ assay. Of the 155 wastewater samples, 62 (40%) tested positive for SARS-CoV-2. Of these, 13 sequences of sufficient length to determine SARS-CoV-2 lineages were obtained and 2 sequences were phylogenetically analyzed. Various Omicron subvariants were detected in wastewater including BA.5, XBB.1.45, BA.2.86, and JN.1. Some of these subvariants have been detected in clinical cases in Zambia. Interestingly, phylogenetic analysis positioned a sequence from the Copperbelt Province in the B.1.1.529 clade, suggesting that earlier Omicron variants detected in late 2021 could still be circulating and may not have been wholly replaced by newer subvariants. This study stresses the need for integrating wastewater surveillance of SARS-CoV-2 into mainstream strategies for monitoring SARS-CoV-2 circulation in Zambia.

Current status and molecular epidemiology of rabies virus from different hosts and regions in Malawi.

Although rabies is endemic in Malawi, there have been no studies in which rabies virus was systematically investigated and characterized in multiple animal hosts in that country. In order to provide molecular epidemiological data on rabies virus in Malawi, 683 suspected rabies case reports from 2008 to 2021 were examined, and 46 (dog = 40, cow = 5, and cat = 1) viable rabies-positive brain samples archived at the Central Veterinary Laboratory (CVL), Lilongwe, Malawi, were analyzed genetically. The results showed an increase in the submission of brain samples from 2008 to 2010, with the highest number of submissions observed in 2020. Of the 683 case reports analyzed for the period under review, 38.1% (260/683) (CI: 34.44 - 41.84) were confirmed by direct fluorescent antibody test. Among the confirmed cases, 65.4% (170/260) (CI: 59.23 - 71.09) were canine rabies. Further, phylogenetic analysis revealed that sequences from different animal hosts clustered together within the Africa 1b lineage, suggesting that the strains circulating in livestock are similar to those in domestic dogs. This finding supports the hypothesis that canine rabies is spilling over to livestock and emphasizes the need for further studies to provide data for effective control of rabies in Malawi.

Autochthonous Leishmania infantum in Dogs, Zambia, 2021.

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.

Isolation, discrimination, and molecular detection of Listeria species from slaughtered cattle in Namwala District, Zambia.

BACKGROUND: The food industry is increasingly becoming more scrutinized, given the frequency and intensity with which zoonotic diseases are being reported. Pathogen tracking has become more applicable with regards food safety. It is in this regard that the present study was formulated to track Listeria species. in freshly slaughtered cattle carcasses by utilizing standard and molecular biological techniques. METHODS: A cross-sectional study design was conducted from March to December 2020 with 200 samples being equally collected in the rainy and dry seasons. A total of 180 and 20 swabs were aseptically collected from carcasses and the environment respectively. Samples were first subjected to pre-enrichment in half-strength Fraser broth followed by enrichment in full strength Fraser broth and subsequent plating on Listeria agar. Listeria growth characteristics were identified up to species level based on their morphological and biochemical characteristics. Further, molecular detection and phylogenetic analysis was conducted. Quantitative proportionate survey data were analyzed using Stata Version 15 software to estimate crude prevalence taking into account complex design at abattoir level. Factors associated with contamination were characterized using logistic regression. Sequences were analyzed using, Genetyyx version 12 and phylogenetic Mega. RESULTS: Of the 200 samples, 19 were positive for Listeria species identified as L.innocua 14/19 (73.7%) and L. monocytogenes 5/19 (26.3%). All isolates were from freshly slaughtered carcasses, and none from environment. Siginificant differences in contamination levels were observed based on season: rainy season yielded 14 (73.6%) whilst the dry season 5 (26.3%). The L. monocytogenes strains showed a high degree of homogeneity on phylogenetic analysis and clustered based on abattoir. Seasonality was identified as a major determinant influencing contamination based on the final logistic regression model. CONCLUSION: This study found evidence of L. monocytogenes contamination on traditionally raised beef carcasses across various abattoirs surveyed. The failure to find Listeria contamination on the abattoir environment may to a greater extent intimate cattle carccases as primary sources of contamination. However, a more comprerehnsive study incorporating different geographical regions is needed to conclusively ascertain these present findings.

Genotyping of Theileria parva populations in vaccinated and non-vaccinated cattle in Malawi.

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.

Genetic diversity of rabies virus in different host species and geographic regions of Zambia and Zimbabwe.

Rabies is endemic in Zambia and Zimbabwe. The previously investigated strains of rabies virus in central Zambia belong to the Africa 1b lineage, with similar circulating virus strains found in the various tested hosts and regions. However, prior work assessed only limited regions and host species. Thus, this study aimed to more comprehensively determine the genetic diversity of rabies virus across regions of Zambia and Zimbabwe. RNA (n = 76) was extracted from positive direct fluorescent antibody test brain tissues from dog, cow, goat, cat, pig, human, and jackal collected from Zambia and Zimbabwe. The amplicons of the nucleoprotein and glycoprotein genes were obtained from all examined samples by nested RT-PCR and subsequently sequenced. A phylogenetic analysis of the N gene confirmed that all the endemic strains of rabies virus in Zambia and Zimbabwe belong to the Africa 1b lineage. The obtained viral gene sequences were phylogenetically divided into two clusters. Cluster II comprised only Zambian strains. In contrast, cluster I comprised both Zambia and Zimbabwe strains, with strains from Zimbabwe forming a distinct lineage from Zambian strains, implying viral genetic divergence due to geographical barriers. However, no evidence of clustering based on host or region was observed, implying the circulation of similar virus strains occurs in different hosts and regions of Zambia and Zimbabwe. The clustering of rabies virus strains from jackals with those from domestic animals provides evidence of similar virus strains circulating in both wildlife and domestic animals, and that the jackal might be one of the potential reservoirs of rabies virus infection. In this study, no strains circulating in Zimbabwe were detected in Zambia.

Prevalence and risk factors associated with Theileria parva infection in cattle in three regions of Tanzania.

Ticks and tickborne diseases (TBDs) are serious constraints to cattle production in Tanzania and other tropical and subtropical countries. Among the TBDs, East Coast fever (ECF) is the most important as it causes significant economic losses to the cattle industry in Tanzania. However, control of ECF in Tanzania has continued to be a challenge due to inadequate epidemiological information. The main objective of this study was to determine the epidemiological situation of Theileria parva infections in cattle kept under pastoral and agro-pastoral farming systems in Mara, Singida, and Mbeya regions of Tanzania. Blood samples were collected from 648 cattle in the three regions. Genomic DNA was extracted and amplified in a polymerase chain reaction (PCR) using T. parva-specific primers targeting the 104-kD antigen (P104) gene. In addition, information was collected on the possible risk factors of T. parva infection (animal age, region, animal sex, tick burden, tick control method, and frequency of acaricide application). The prevalence of T. parva across the three regions was 14.2%. There was variation in prevalence among the three regions with Mara (21.8%) having a significantly higher (p = 0.001) prevalence than the other regions. Moreover, Mbeya exhibited relatively lower prevalence (7.4%) compared to the other regions. Factors found to be significantly associated with an animal being PCR positive for T. parva were region (p = 0.001) and tick burden (p = 0.003). Other factors were not found to be significant predictors of being PCR positive for T. parva. The present study showed high variation in tick burden and T. parva prevalence across the regions. Therefore, different strategic planning and cost-effective control measures for ticks and T. parva infection should be implemented region by region in order to reduce losses caused by ticks and ECF in the study area.

Molecular epidemiology of paramyxoviruses in Zambian wild rodents and shrews.

Rodents and shrews are known to harbour various viruses. Paramyxoviruses have been isolated from Asian and Australian rodents, but little is known about them in African rodents. Recently, previously unknown paramyxovirus sequences were found in South African rodents. To date, there have been no reports related to the presence and prevalence of paramyxoviruses in shrews. We found a high prevalence of paramyxoviruses in wild rodents and shrews from Zambia. Semi-nested reverse transcription-PCR assays were used to detect paramyxovirus RNA in 21 % (96/462) of specimens analysed. Phylogenetic analysis revealed that these viruses were novel paramyxoviruses and could be classified as morbillivirus- and henipavirus-related viruses, and previously identified rodent paramyxovirus-related viruses. Our findings suggest the circulation of previously unknown paramyxoviruses in African rodents and shrews, and provide new information regarding the geographical distribution and genetic diversity of paramyxoviruses.

p67 gene alleles sequence analysis reveals Theileria parva parasites associated with East Coast fever and Corridor disease in buffalo from Zambia.

Theileriosis caused by Theileria parva infections is responsible for high cattle mortalities in Zambia. Although infected buffalo are a risk to cattle, the characterization of T. parva parasites occurring in this host in Zambia has not been reported. Furthermore, considering the advances in the development of a p67 subunit vaccine, the knowledge of p67 genetic and antigenic diversity in both cattle and buffalo associated T. parva is crucial. Therefore, blood samples from buffalo (n=43) from Central, Eastern and Southern provinces, and cattle (n=834) from Central, Copperbelt, Eastern, Lusaka, and Southern provinces, were tested for T. parva infection and the parasites characterized by sequencing the gene encoding the p67 antigen. About 76.7 % of buffalo and 19.3 % of cattle samples were PCR positive for T. parva. Three of the four known p67 allele types (1, 2 and 3) were identified in parasites from buffalo, of which two (allele types 2 and 3) are associated with T. parva parasites responsible for Corridor disease. Only allele type 1, associated with East Coast fever, was identified from cattle samples, consistent with previous reports from Zambia. Phylogenetic analysis revealed segregation between allele type 1 sequences from cattle and buffalo samples as they grouped separately within the same sub-clade. The high occurrence of T. parva infection in buffalo samples investigated demonstrates the risk of Corridor disease infection, or even outbreaks, should naïve cattle co-graze with infected buffalo in the presence of the tick vector. In view of a subunit vaccine, the antigenic diversity in buffalo associated T. parva should be considered to ensure broad protection. The current disease control measures in Zambia may require re-evaluation to ensure that cattle are protected against buffalo-derived T. parva infections. Parasite stocks used in 'infection and treatment' immunization in Zambia, have not been evaluated for protection against buffalo-derived T. parva parasites currently circulating in the buffalo population.

Characterization of human respiratory syncytial virus in children with severe acute respiratory infection before and during the COVID-19 pandemic.

Objectives: Annual outbreaks of human respiratory syncytial virus (HRSV) are caused by newly introduced and locally persistent strains. During the COVID-19 pandemic, global and local circulation of HRSV significantly decreased. This study was conducted to characterize HRSV in 2018-2022 and to analyze the impact of COVID-19 on the evolution of HRSV. Design/methods: Combined oropharyngeal and nasopharyngeal swabs were collected from children hospitalized with severe acute respiratory infection at two hospitals in Zambia. The second hypervariable region of the attachment gene G was targeted for phylogenetic analysis. Results: Of 3113 specimens, 504 (16.2%) were positive for HRSV, of which 131 (26.0%) and 66 (13.1%) were identified as HRSVA and HRSVB, respectively. In early 2021, an increase in HRSV was detected, caused by multiple distinct clades of HRSVA and HRSVB. Some were newly introduced, whereas others resulted from local persistence. Conclusions: This study provides insights into the evolution of HRSV, driven by global and local circulation. The COVID-19 pandemic had a temporal impact on the evolution pattern of HRSV. Understanding the evolution of HRSV is vital for developing strategies for its control.

Rabies Realities: Navigating Barriers to Rabies Control in Rural Zambia-A Case Study of Manyinga and Mwansabombwe Districts.

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.

Molecular Detection and Characterization of Rickettsia Species in Ixodid Ticks from Selected Regions of Namibia.

Rickettsial pathogens are among the emerging and re-emerging vector-borne zoonoses of public health importance. Reports indicate human exposure to Rickettsial pathogens in Namibia through serological surveys, but there is a lack of data on infection rates in tick vectors, hindering the assessment of the relative risk to humans. Our study sought to screen Ixodid ticks collected from livestock for the presence of Rickettsia species in order to determine infection rates in ticks and to determine the Rickettsia species circulating in the country. We collected and pooled Hyalomma and Rhipicephalus ticks from two adjacent regions of Namibia (Khomas and Otjozondjupa) and observed an overall minimum Rickettsia infection rate of 8.6% (26/304), with an estimated overall pooled prevalence of 9.94% (95% CI: 6.5-14.3). There were no statistically significant differences in the estimated pooled prevalence between the two regions or tick genera. Based on the nucleotide sequence similarity and phylogenetic analysis of the outer membrane protein A (n = 9) and citrate synthase (n = 12) genes, BLAST analysis revealed similarity between Rickettsia africae (n = 2) and Rickettsia aeschlimannii (n = 11), with sequence identities ranging from 98.46 to 100%. Our initial study in Namibia indicates that both zoonotic R. africae and R. aeschlimannii are in circulation in the country, with R. aeschlimannii being the predominant species.

Molecular detection and phylogenetic characterization of Rickettsia in ticks collected from leopard tortoise (Geochelone pardalis) in rural Zambia.

In sub-Saharan Africa, limited studies have investigated zoonotic pathogens that may be harboured by ticks infesting reptiles such as tortoises. Here, we report the presence of pathogenic Rickettsia in ticks (Amblyomma marmoreum) collected from the leopard tortoise (Geochelone pardalis) in rural Zambia. Using polymerase chain reaction, 56% (49/87) of ticks were positive for the Rickettsia outer membrane protein (ompB) gene. Multi-locus sequence and phylogenetic analysis based on the ompB, ompA, and citrate synthase (gltA) genes showed that the ticks carried R. africae, and other Rickettsia spp. closely related to R . raoultii, R . massiliae, R . tamurae and R . monacensis. Given the proximity between humans, livestock, and wildlife in these habitats, there exists a considerable risk of transmission of zoonotic Rickettsia to human populations in this rural setting. These results call for heightened awareness and further research into the dynamics of tick-borne diseases in regions where humans and animals coexist, particularly in the context of tortoise-associated ticks as vectors. Understanding and addressing these potential disease vectors is crucial for effective public health measures and the prevention of Rickettsia zoonoses.

Detection of Extended-Spectrum Beta-Lactamase (ESBL)-Producing Enterobacteriaceae from Diseased Broiler Chickens in Lusaka District, Zambia.

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.

Genotypic Characterisation and Antimicrobial Resistance of Extended-Spectrum ß-Lactamase-Producing Escherichia coli in Humans, Animals, and the Environment from Lusaka, Zambia: Public Health Implications and One Health Surveillance.

BACKGROUND: Extended-spectrum ß-lactamases (ESBL) in Escherichia coli are a serious concern due to their role in developing multidrug resistance (MDR) and difficult-to-treat infections. OBJECTIVE: This study aimed to identify ESBL-carrying E. coli strains from both clinical and environmental sources in Lusaka District, Zambia. METHODS: This cross-sectional study included 58 ESBL-producing E. coli strains from hospital inpatients, outpatients, and non-hospital environments. Antimicrobial susceptibility was assessed using the Kirby-Bauer disk diffusion method and the VITEK® 2 Compact System, while genotypic analyses utilised the Illumina NextSeq 2000 sequencing platform. RESULTS: Among the strains isolated strains, phylogroup B2 was the most common, with resistant MLST sequence types including ST131, ST167, ST156, and ST69. ESBL genes such as blaTEM-1B, blaCTX-M,blaOXA-1, blaNDM-5, and blaCMY were identified, with ST131 and ST410 being the most common. ST131 exhibited a high prevalence of blaCTX-M-15 and resistance to fluoroquinolones. Clinical and environmental isolates carried blaNDM-5 (3.4%), with clinical isolates showing a higher risk of carbapenemase resistance genes and the frequent occurrence of blaCTX-M and blaTEM variants, especially blaCTX-M-15 in ST131. CONCLUSIONS: This study underscores the public health risks of blaCTX-M-15- and blaNDM-5-carrying E. coli. The strengthening antimicrobial stewardship programmes and the continuous surveillance of AMR in clinical and environmental settings are recommended to mitigate the spread of resistant pathogens.

Expanding diversity of bunyaviruses identified in mosquitoes.

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.

Molecular detection and characterization of Anaplasma spp. in cattle and sable antelope from Lusaka and North-Western provinces of Zambia.

Rickettsiales of the genus Anaplasma are globally distributed tick-borne pathogens of animals and humans with complex epidemiological cycles. Anaplasmosis is an important livestock disease in Zambia but its epidemiological information is inadequate. This study aimed to detect and characterize the species of Anaplasma present in domestic and wild ruminants in Zambia with a focus on the infection risk posed by the translocation of sable antelope (Hippotragus niger) from North-Western Province to Lusaka Province. Archived DNA samples (n = 100) extracted from whole blood (sable n = 47, cattle n = 53) were screened for Anaplasmataceae using 16S rRNA partial gene amplification followed by species confirmation using phylogenetic analysis. Out of the 100 samples, Anaplasma species were detected in 7% (4/57) of the cattle and 24% (10/43) of the sable antelope samples. Of the 14 positive samples, five were determined to be A. marginale (four from cattle and one from sable), seven were A. ovis (sable) and two were A. platys (sable). Phylogenetic analysis of the 16S rRNA partial gene sequences revealed genetic proximity between A. ovis and A. marginale, regardless of host. The detection of Anaplasma in wildlife in Zambia shows the risk of transmission of Anaplasma species associated with wildlife translocation.

Antibiotic Resistance Patterns of Listeria Species Isolated from Broiler Abattoirs in Lusaka, Zambia.

L. monocytogenes is a public health threat linked to fast foods such as broiler chickens. This study aimed to verify the occurrence of Listeria species in chickens from abattoirs and evaluate their antimicrobial resistance. In total, 150 broiler carcass swabs distributed as cloacal (n = 60), exterior surface (n = 60), and environmental (n = 30) were collected. Listeria species were characterized using biochemical tests and PCR. We conducted antibiotic resistance tests using the disc diffusion and Etest (Biomerieux, Durham, NC, USA) methods. Overall isolation of Listeria species was 15% (23/150) 95% CI (10.16-22.33), 2% (3/150) 95% CI (0.52-6.19) and 13% (20/150) 95% CI (8.53-20.08) came from environmental swabs and carcass swabs, respectively. Proportions of positive Listeria isolates were L. monocytogenes 74% (17/23), L. welshimeri 22% (5/23), and L. innocua 4% (1/23). Listeria species from the exterior carcass swabs was 61% (14/23), cloacal swabs 26% (6/23), and environmental swabs 3% (3/23). L. monocytogenes had the greatest resistance percentage to the following antibiotics: clindamycin (61%, 10/23), tetracycline 30% (7/23), and erythromycin 13%, (3/23). Isolation of L. monocytogenes in relatively high numbers, including the antimicrobial profiles, suggests a potential risk of the pathogen remaining viable in the food continuum and a public health risk to would-be consumers.

Sequence Diversity of Tp1 and Tp2 Antigens and Population Genetic Analysis of Theileria parva in Unvaccinated Cattle in Zambia's Chongwe and Chisamba Districts.

East Coast Fever (ECF), caused by Theileria parva, is a major constraint to improved livestock keeping in east and central Africa, including Zambia. To understand the dynamics and determine the candidates for immunization in Zambia's Chongwe and Chisamba districts, a combination of Tp1 and Tp2 gene sequencing and microsatellite analysis using nine markers was conducted from which an abundance of Muguga, Kiambu, Serengeti and Katete epitopes in the field samples was obtained. Phylogenetic analysis showed six (Tp1) and three (Tp2) clusters with an absence of geographical origin clustering. The majority of haplotypes were related to Muguga, Kiambu, Serengeti and Katete, and only a few were related to Chitongo. Both antigens showed purifying selection with an absence of positive selection sites. Furthermore, low to moderate genetic differentiation was observed among and within the populations, and when vaccine stocks were compared with field samples, Chongwe samples showed more similarity to Katete and less to Chitongo, while Chisamba samples showed similarity to both Katete and Chitongo and not to Muguga, Kiambu or Serengeti. We conclude that the use of Katete stock for immunization trials in both Chongwe and Chisamba districts might produce desirable protection against ECF.