Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 25
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Parasitol Res ; 123(7): 272, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39012570

RESUMEN

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.


Asunto(s)
Variación Genética , Haplotipos , Filogenia , Schistosoma haematobium , Esquistosomiasis Urinaria , Zambia/epidemiología , Animales , Humanos , Schistosoma haematobium/genética , Schistosoma haematobium/aislamiento & purificación , Schistosoma haematobium/clasificación , Niño , Esquistosomiasis Urinaria/parasitología , Esquistosomiasis Urinaria/epidemiología , Masculino , Preescolar , Femenino , Genética de Población , Adolescente
2.
J Infect Dis ; 218(suppl_5): S312-S317, 2018 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-29889270

RESUMEN

Bats are suspected to play important roles in the ecology of filoviruses, including ebolaviruses and marburgviruses. A cave-dwelling fruit bat, Rousettus aegyptiacus, has been shown to be a reservoir of marburgviruses. Using an enzyme-linked immunosorbent assay with the viral glycoprotein antigen, we detected immunoglobulin G antibodies specific to multiple filoviruses in 158 of 290 serum samples of R aegyptiacus bats captured in Zambia during the years 2014-2017. In particular, 43.8% of the bats were seropositive to marburgvirus, supporting the notion that this bat species continuously maintains marburgviruses as a reservoir. Of note, distinct peaks of seropositive rates were repeatedly observed at the beginning of rainy seasons, suggesting seasonality of the presence of newly infected individuals in this bat population. These data highlight the need for continued monitoring of filovirus infection in this bat species even in countries where filovirus diseases have not been reported.


Asunto(s)
Quirópteros/sangre , Quirópteros/inmunología , Infecciones por Filoviridae/sangre , Infecciones por Filoviridae/inmunología , Filoviridae/inmunología , Animales , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Quirópteros/virología , Reservorios de Enfermedades/virología , Femenino , Infecciones por Filoviridae/virología , Glicoproteínas/sangre , Glicoproteínas/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Masculino , Estudios Seroepidemiológicos , Zambia
3.
BMC Microbiol ; 18(1): 2, 2018 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-29433443

RESUMEN

BACKGROUND: Plague is a flea-borne zoonotic and invasive disease caused by a gram negative coccobacillus bacterium called Yersinia pestis. Plague has caused three devastating pandemics globally namely: the Justinian, Black Death and Oriental plague. The disease in the Eastern Province of Zambia has been reported in Nyimba and Sinda Districts in the past 15 years. The aim of this study was to investigate the molecular epidemiology of plague in the two affected districts. Polymerase Chain Reaction (PCR), targeting Plasminogen activator gene (pla gene) of Y. pestis, was performed on suspected human bubo aspirates (n = 7), rodents (n = 216), shrews (n = 27) and fleas (n = 1494). Of these, one positive sample from each source or host was subjected to sequencing followed by phylogenetic analysis. RESULTS: The plasminogen activator gene (pla gene) of Y. pestis was detected in 42.8% bubo aspirates, 6.9% rodents, 3.7% shrew and 0.8% fleas. The fleas were from pigs (n = 4), goats (n = 5) and rodents (n = 3). The sequencing and phylogenetic analysis suggested that the pla gene of Y. pestis in Nyimba and Sinda was similar and the isolates demonstrated a high degree of evolutionary relationship with Antiqua strains from the Republic of Congo and Kenya. CONCLUSION: It can be concluded that pla gene of Y. pestis was present in various hosts in the two districts and the strains circulating in each district were similar and resembles those in the Republic of Congo and Kenya.


Asunto(s)
Proteínas Bacterianas/genética , Reservorios de Enfermedades/microbiología , Epidemiología Molecular , Peste/microbiología , Activadores Plasminogénicos/genética , Yersinia pestis/genética , Yersinia pestis/aislamiento & purificación , Animales , Congo , ADN Bacteriano/genética , Brotes de Enfermedades , Monitoreo Epidemiológico/veterinaria , Evolución Molecular , Cabras , Humanos , Kenia , Filogenia , Peste/epidemiología , Peste/transmisión , Reacción en Cadena de la Polimerasa/veterinaria , Roedores/microbiología , Roedores/parasitología , Análisis de Secuencia , Musarañas , Siphonaptera/microbiología , Porcinos , Yersinia pestis/clasificación , Zambia
4.
Arch Virol ; 161(3): 513-9, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26597187

RESUMEN

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive viral disease of young chickens and remains one of the economically most important diseases threatening the poultry industry worldwide. In this study, 16 and 11 nucleotide sequences of the VP2 hypervariable region (VP2-HVR) and part of VP1, respectively, of IBD virus (IBDV) detected in vaccinated broiler chickens in Lusaka in 2012 were determined. Phylogenetic analysis revealed that these Zambian IBDVs separated into three genotypes of very virulent (VV) IBDVs. Although the majority of these viruses belonged to the African VV type (VV1), which consisted of viruses from West Africa, South Africa and Zambia, one virus belonged to the East African VV type (VV2). Interestingly, a Zambian IBDV belonging to the VV3 genotype (composed of viruses from several continents) clustered with attenuated vaccine strains. Although sequence analysis of VP2-HVR showed that all detected Zambian IBDVs had conserved putative virulence marker amino acids (i.e., 222A, 242I, 256I, 294I and 299S), one virus had two unique amino acid substitutions, N280S and E300A. This study demonstrates the diversity of Zambian IBDVs and documents for the first time the possible involvement of attenuated vaccine strains in the epidemiology of IBD in Zambia. Strict biosecurity of poultry farms, monitoring of live vaccine use in the field, surveillance and characterization of IBDV in poultry and development of a vaccine from local or regional IBDV field strains are recommended for improved IBD control in Zambia.


Asunto(s)
Infecciones por Birnaviridae/veterinaria , Virus de la Enfermedad Infecciosa de la Bolsa/clasificación , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Enfermedades de las Aves de Corral/virología , Animales , Infecciones por Birnaviridae/virología , Pollos , Análisis por Conglomerados , Genotipo , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Datos de Secuencia Molecular , Filogenia , ARN Viral/genética , Análisis de Secuencia de ADN , Homología de Secuencia , Proteínas Estructurales Virales/genética , Zambia
5.
J Infect Dis ; 212 Suppl 2: S101-8, 2015 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-25786916

RESUMEN

Fruit bats are suspected to be a natural reservoir of filoviruses, including Ebola and Marburg viruses. Using an enzyme-linked immunosorbent assay based on the viral glycoprotein antigens, we detected filovirus-specific immunoglobulin G antibodies in 71 of 748 serum samples collected from migratory fruit bats (Eidolon helvum) in Zambia during 2006-2013. Although antibodies to African filoviruses (eg, Zaire ebolavirus) were most prevalent, some serum samples showed distinct specificity for Reston ebolavirus, which that has thus far been found only in Asia. Interestingly, the transition of filovirus species causing outbreaks in Central and West Africa during 2005-2014 seemed to be synchronized with the change of the serologically dominant virus species in these bats. These data suggest the introduction of multiple species of filoviruses in the migratory bat population and point to the need for continued surveillance of filovirus infection of wild animals in sub-Saharan Africa, including hitherto nonendemic countries.


Asunto(s)
Quirópteros/virología , Infecciones por Filoviridae/epidemiología , Infecciones por Filoviridae/virología , Filoviridae/inmunología , África/epidemiología , Animales , Anticuerpos Antivirales/sangre , Asia/epidemiología , Línea Celular , Quirópteros/sangre , Quirópteros/inmunología , Brotes de Enfermedades , Ebolavirus/inmunología , Femenino , Infecciones por Filoviridae/sangre , Infecciones por Filoviridae/inmunología , Glicoproteínas/inmunología , Células HEK293 , Fiebre Hemorrágica Ebola/sangre , Fiebre Hemorrágica Ebola/epidemiología , Fiebre Hemorrágica Ebola/inmunología , Fiebre Hemorrágica Ebola/virología , Humanos , Inmunoglobulina G/sangre , Masculino , Prevalencia , Proteínas Virales/inmunología
6.
J Gen Virol ; 96(Pt 2): 440-452, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25381053

RESUMEN

Shrews are small insectivorous mammals that are distributed worldwide. Similar to rodents, shrews live on the ground and are commonly found near human residences. In this study, we investigated the enteric virome of wild shrews in the genus Crocidura using a sequence-independent viral metagenomics approach. A large portion of the shrew enteric virome was composed of insect viruses, whilst novel viruses including cyclovirus, picornavirus and picorna-like virus were also identified. Several cycloviruses, including variants of human cycloviruses detected in cerebrospinal fluid and stools, were detected in wild shrews at a high prevalence rate. The identified picornavirus was distantly related to human parechovirus, inferring the presence of a new genus in this family. The identified picorna-like viruses were characterized as different species of calhevirus 1, which was discovered previously in human stools. Complete or nearly complete genome sequences of these novel viruses were determined in this study and then were subjected to further genetic characterization. Our study provides an initial view of the diversity and distinctiveness of the shrew enteric virome and highlights unique novel viruses related to human stool-associated viruses.


Asunto(s)
Biota , Intestinos/virología , Metagenoma , Musarañas/virología , Virus/clasificación , Virus/genética , Animales , Análisis por Conglomerados , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN
7.
J Gen Virol ; 95(Pt 2): 325-330, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24189618

RESUMEN

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.


Asunto(s)
Infecciones por Paramyxoviridae/veterinaria , Paramyxoviridae/clasificación , Paramyxoviridae/aislamiento & purificación , Roedores/virología , Musarañas/virología , Animales , Análisis por Conglomerados , Epidemiología Molecular , Datos de Secuencia Molecular , Paramyxoviridae/genética , Infecciones por Paramyxoviridae/epidemiología , Infecciones por Paramyxoviridae/virología , Filogenia , Reacción en Cadena de la Polimerasa , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Homología de Secuencia , Zambia/epidemiología
8.
Trop Med Infect Dis ; 9(7)2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-39058203

RESUMEN

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.

9.
Microorganisms ; 12(2)2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38399757

RESUMEN

Poultry production is essential to the economy and livelihood of many rural Zambian households. However, the industry is threatened by infectious diseases, particularly Newcastle disease virus (NDV) infection. Therefore, this study employed next-generation sequencing to characterise six NDV isolates from poultry in Zambia's live bird markets (LBMs) and wild waterfowl. Four NDV isolates were detected from 410 faecal samples collected from chickens in LBMs in Lusaka and two from 2851 wild birds from Lochinvar National Park. Phylogenetic analysis revealed that the four NDVs from LBM clustered in genotype VII and sub-genotype VII.2 were closely related to viruses previously isolated in Zambia and other Southern African countries, suggesting possible local and regional transboundary circulation of the virus. In contrast, the two isolates from wild birds belonged to class I viruses, genotype 1, and were closely related to isolates from Europe and Asia, suggesting the possible introduction of these viruses from Eurasia, likely through wild bird migration. The fusion gene cleavage site motif for all LBM-associated isolates was 112RRQKR|F117, indicating that the viruses are virulent, while the isolates from wild waterfowl had the typical 112ERQER|L117 avirulent motif. This study demonstrates the circulation of virulent NDV strains in LBMs and has, for the first time, characterised NDV from wild birds in Zambia. The study further provides the first whole genomes of NDV sub-genotype VII.2 and genotype 1 from Zambia and stresses the importance of surveillance and molecular analysis for monitoring the circulation of NDV genotypes and viral evolution.

10.
Emerg Infect Dis ; 19(9)2013.
Artículo en Inglés | MEDLINE | ID: mdl-23968816

RESUMEN

Human parainfluenza virus type 3 (HPIV3) genome was detected in 4 baboons in Zambia. Antibody for HPIV3 was detected in 13 baboons and 6 vervet monkeys in 2 distinct areas in Zambia. Our findings suggest that wild nonhuman primates are susceptible to HPIV3 infection.


Asunto(s)
Chlorocebus aethiops/virología , Enfermedades de los Monos/epidemiología , Papio/virología , Virus de la Parainfluenza 3 Humana/genética , Infecciones por Respirovirus/veterinaria , Animales , Humanos , Datos de Secuencia Molecular , Virus de la Parainfluenza 3 Humana/clasificación , Filogenia , Serotipificación , Proteínas Virales/genética , Zambia/epidemiología
11.
J Gen Virol ; 94(Pt 6): 1357-1364, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23426354

RESUMEN

To examine polyomavirus (PyV) infection in wildlife, we investigated the presence of PyVs in Zambia with permission from the Zambia Wildlife Authority. We analysed 200 DNA samples from the spleens and kidneys (n = 100 each) of yellow baboons and vervet monkeys (VMs) (n = 50 each). We detected seven PyV genome fragments in 200 DNA samples using a nested broad-spectrum PCR method, and identified five full-length viral genomes using an inverse PCR method. Phylogenetic analysis of virally encoded proteins revealed that four PyVs were closely related to either African green monkey PyV or simian agent 12. Only one virus detected from a VM spleen was found to be related, with relatively low nucleotide sequence identity (74 %), to the chimpanzee PyV, which shares 48 % nucleotide sequence identity with the human Merkel cell PyV identified from Merkel cell carcinoma. The obtained entire genome of this virus was 5157 bp and had large T- and small t-antigens, and VP1 and VP2 ORFs. This virus was tentatively named vervet monkey PyV 1 (VmPyV1) as a novel PyV. Comparison with other PyVs revealed that VmPyV1, like chimpanzee PyV, had a longer VP1 ORF. To examine whether the VmPyV1 genome could produce viral proteins in cultured cells, the whole genome was transfected into HEK293T cells. We detected VP1 protein expression in the transfected HEK293T cells by immunocytochemical and immunoblot analyses. Thus, we identified a novel PyV genome from VM spleen.


Asunto(s)
Chlorocebus aethiops/virología , Infecciones por Polyomavirus/veterinaria , Poliomavirus/aislamiento & purificación , Enfermedades de los Primates/virología , Animales , Secuencia de Bases , Genoma Viral , Células HEK293 , Humanos , Riñón/virología , Datos de Secuencia Molecular , Filogenia , Poliomavirus/clasificación , Poliomavirus/genética , Poliomavirus/fisiología , Infecciones por Polyomavirus/virología , Bazo/virología , Zambia
12.
Microorganisms ; 11(1)2023 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-36677492

RESUMEN

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.

13.
J Gen Virol ; 93(Pt 10): 2247-2251, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22815269

RESUMEN

In order to survey arenaviruses in the Republic of Zambia, we captured 335 rodents from three cities between 2010 and 2011. Eighteen Luna virus (LUNV) and one lymphocytic choriomeningitis virus (LCMV)-related virus RNAs were detected by one-step RT-PCR from Mastomys natalensis and Mus minutoides, respectively. Four LUNV strains and one LCMV-related virus were isolated, and the whole genome nucleotide sequence was determined by pyrosequencing. Phylogenetic analyses revealed that the LUNV clade consists of two branches that are distinguished by geographical location and that the LCMV-related virus belongs to the LCMV clade, but diverges from the typical LCMVs. Comparison of nucleoprotein amino acid sequences indicated that the LCMV-related virus could be designated a novel arenavirus, which was tentatively named as the Lunk virus. Amino acid sequences of the GP, NP, Z and L proteins showed poor similarity among the three Zambian arenavirus strains, i.e. Luna, Lunk and Lujo virus.


Asunto(s)
Arenavirus del Viejo Mundo/clasificación , Genoma Viral , Nucleoproteínas/genética , Secuencia de Aminoácidos , Animales , Arenavirus del Viejo Mundo/genética , Secuencia de Bases , Datos de Secuencia Molecular , Filogenia , ARN Viral/genética , Roedores/genética , Roedores/virología , Zambia
14.
Antibiotics (Basel) ; 11(7)2022 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-35884098

RESUMEN

Pigs have been shown to be a reservoir for recently emerging livestock-associated Staphylococcus aureus (LA-SA), including methicillin resistant strains in many countries worldwide. However, there is sparse information about LA-SA strains circulating in Zambia. This study investigated the prevalence, phenotypic and genotypic characteristics of S. aureus from pigs and workers at farms and abattoirs handling pigs in Lusaka Province of Zambia. A total of 492 nasal pig swabs, 53 hand and 53 nasal human swabs were collected from farms and abattoirs in selected districts. Standard microbiological methods were used to isolate and determine antimicrobial susceptibility patterns of S. aureus. Polymerase Chain Reaction was used to confirm the species identity and detect antimicrobial resistance and virulence genes of isolates, whereas genetic diversity was evaluated using spa typing. Overall prevalence of S. aureus was 33.1%, 37.8% for pigs and 11.8% for humans. The isolates were resistant to several antibiotics with resistance ranging from 18% to 98% but were all susceptible to vancomycin. Typical LA-SA spa types were detected. The presence of plasmid mediated resistance genes such as tetM (12.8%), other resistance determinants and immune evasion cluster genes among the isolates is of great public health concern. Thus, continuous surveillance of S. aureus using a "One health" approach is warranted to monitor S.aureus infections and spread of antimicrobial resistance.

15.
Emerg Infect Dis ; 17(10): 1921-4, 2011 10.
Artículo en Inglés | MEDLINE | ID: mdl-22000372

RESUMEN

To investigate arenavirus in Zambia, we characterized virus from the kidneys of 5 arenavirus RNA-positive rodents (Mastomys natalensis) among 263 captured. Full-genome sequences of the viruses suggested that they were new strains similar to Lassa virus-related arenaviruses. Analyzing samples from additional rodents and other species can elucidate epizootiologic aspects of arenaviruses.


Asunto(s)
Arenavirus/clasificación , Animales , Infecciones por Arenaviridae/veterinaria , Infecciones por Arenaviridae/virología , Arenavirus/genética , Arenavirus/aislamiento & purificación , Datos de Secuencia Molecular , Murinae , Filogenia , ARN Viral/análisis , Enfermedades de los Roedores/virología , Proteínas de la Matriz Viral/genética , Zambia
16.
J Gen Virol ; 92(Pt 6): 1416-1427, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21367986

RESUMEN

Although the quest to clarify the role of wild birds in the spread of the highly pathogenic H5N1 avian influenza virus (AIV) has yielded considerable data on AIVs in wild birds worldwide, information regarding the ecology and epidemiology of AIVs in African wild birds is still very limited. During AIV surveillance in Zambia (2008-2009), 12 viruses of distinct subtypes (H3N8, H4N6, H6N2, H9N1 and H11N9) were isolated from wild waterfowl. Phylogenetic analyses demonstrated that all the isolates were of the Eurasian lineage. Whilst some genes were closely related to those of AIVs isolated from wild and domestic birds in South Africa, intimating possible AIV exchange between wild birds and poultry in southern Africa, some gene segments were closely related to those of AIVs isolated in Europe and Asia, thus confirming the inter-regional AIV gene flow among these continents. Analysis of the deduced amino acid sequences of internal proteins revealed that several isolates harboured particular residues predominantly observed in human influenza viruses. Interestingly, the isolates with human-associated residues exhibited higher levels of virus replication in the lungs of infected mice and caused more morbidity as measured by weight loss than an isolate lacking such residues. This study stresses the need for continued monitoring of AIVs in wild and domestic birds in southern Africa to gain a better understanding of the emergence of strains with the potential to infect mammals.


Asunto(s)
Animales Salvajes/virología , Anseriformes/virología , Virus de la Influenza A/clasificación , Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/virología , Animales , Heces/virología , Humanos , Virus de la Influenza A/genética , Virus de la Influenza A/patogenicidad , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Filogenia , Proteínas Virales/genética , Virulencia , Zambia
17.
PLoS Negl Trop Dis ; 15(4): e0009222, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33909621

RESUMEN

BACKGROUND: An estimated 75% or more of the human rabies cases in Africa occur in rural settings, which underscores the importance of rabies control in these areas. Understanding dog demographics can help design strategies for rabies control and plan and conduct canine mass vaccination campaigns effectively in African countries. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional survey was conducted to investigate domestic dog demographics in Kalambabakali, in the rural Mazabuka District of Zambia. The population of ownerless dogs and the total achievable vaccination coverage among the total dog population was estimated using the capture-recapture-based Bayesian model by conducting a canine mass vaccination campaign. This study revealed that 29% of the domestic dog population was under one year old, and 57.7% of those were under three months old and thus were not eligible for the canine rabies vaccination in Zambia. The population growth was estimated at 15% per annum based on the cross-sectional household survey. The population of ownerless dogs was estimated to be small, with an ownerless-to-owned-dog ratio of 0.01-0.06 in the target zones. The achieved overall vaccination coverage from the first mass vaccination was estimated 19.8-51.6%. This low coverage was principally attributed to the owners' lack of information, unavailability, and dog-handling difficulties. The follow-up mass vaccination campaign achieved an overall coverage of 54.8-76.2%. CONCLUSIONS/SIGNIFICANCE: This paper indicates the potential for controlling canine rabies through mass vaccination in rural Zambia. Rabies education and responsible dog ownership are required to achieve high and sustainable vaccination coverage. Our findings also propose including puppies below three months old in the target population for rabies vaccination and emphasize that securing an annual enforcement of canine mass vaccination that reaches 70% coverage in the dog population is necessary to maintain protective herd immunity.


Asunto(s)
Enfermedades de los Perros/prevención & control , Vacunas Antirrábicas/inmunología , Rabia/veterinaria , Cobertura de Vacunación/estadística & datos numéricos , Animales , Teorema de Bayes , Estudios Transversales , Perros , Femenino , Masculino , Vacunación Masiva/veterinaria , Propiedad , Rabia/prevención & control , Vacunas Antirrábicas/administración & dosificación , Población Rural , Zambia
18.
Pathogens ; 10(6)2021 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-34208340

RESUMEN

Rabies remains endemic in Zambia. Despite conducting canine vaccinations in Lusaka district, the vaccination coverage and actual seropositivity in the dog population in Lusaka district are rarely evaluated. This study estimated the seropositivity-based immunization coverage in the owned dog population in Lusaka district using the expanded program on immunization cluster survey method. The time-series trend of neutralizing antibodies against rabies in vaccinated dogs was also evaluated. Of 366 dogs in 200 dog-owning households in Lusaka district, blood samples were collected successfully from 251 dogs. In the sampled dogs, 42.2% (106/251) had an antibody titer ≥0.5 IU/mL. When the 115 dogs whose blood was not collected were assumed to be seronegative, the minimum immunization coverage in Lusaka district's owned dog population was estimated at 29.0% (95% confidence interval: 22.4-35.5). It was also found that a single vaccination with certified vaccines is capable of inducing protective levels of antibodies. In contrast, higher antibody titers were observed in multiple-vaccinated dogs than in single-vaccinated dogs, coupled with the observation of a decline in antibody titer over time. These results suggest the importance of continuous booster immunization to maintain herd immunity and provide useful information to plan mass vaccination against rabies in Zambia.

19.
Int J Parasitol Parasites Wildl ; 12: 34-41, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32420023

RESUMEN

The Kafue ecosystem is a vast conservation protected area comprising the Kafue National Park (KNP) and the Game Management Areas (GMA) that act as a buffer around the national park. The KNP has been neglected as a potential foci for rhodesiense sleeping sickness despite the widespread presence of the tsetse vector and abundant wildlife reservoirs. The aim of this study was to generate information on circulating trypanosomes and their eminent threat/risk to public health and livestock production of a steadily growing human and livestock population surrounding the park. We detected various trypanosomes circulating in different mammalian wildlife species in KNP in Zambia by applying a high throughput ITS1-polymerase chain reaction (PCR)/nanopore sequencing method in combination with serum resistant associated-PCR/Sanger sequencing method. The prevalence rates of trypanosomes in hartebeest, sable antelope, buffalo, warthog, impala and lechwe were 6.4%, 37.2%, 13.2%, 11.8%, 2.8% and 11.1%, respectively. A total of six trypanosomes species or subspecies were detected in the wildlife examined, including Trypanosoma brucei brucei, T. godfreyi, T. congolense, T. simiae and T. theileri. Importantly we detected human infective T. b. rhodesiense in buffalo and sable antelope with a prevalence of 9.4% and 12.5%, respectively. In addition, T. b. rhodesiense was found in the only vervet monkey analyzed. The study thus reaffirmed that the Kafue ecosystem is a genuine neglected and re-emerging foci for human African trypanosomiasis. This is the first assessment of the trypanosome diversity circulating in free-ranging wildlife of the KNP.

20.
J Med Entomol ; 54(3): 719-725, 2017 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-28399281

RESUMEN

A cross-sectional study was conducted in the Eastern part of Zambia that previously reported a plague outbreak. The aim of the study was to evaluate the potential role of pigs, goats, and sheep as sero-surveillance hosts for monitoring plague, and to investigate the flea vectors and potential reservoir hosts to establish the current status of plague endemicity in the district. Serum samples were collected from 96 rodents, 10 shrews, 245 domestic pigs, 232 goats, and 31 sheep, whereas 106 organs were eviscerated from rodents and shrews. As for fleas, 1,064 Echidnophaga larina Jordan & Rothschild, 7 Xenopsylla cheopis (Rothschild), and 382 Echidnophaga gallinacea (Westwood) were collected from these animals in 34 villages. Enzyme-Linked Immunosorbent Assay (ELISA) and Polymerase Chain Reaction (PCR) tests were performed on serum, and organs and fleas to determine IgG antibodies against Fraction 1 antigen and pla gene of Yersinia pestis, respectively. ELISA results showed that 2.83% (95% CI = 0.59-8.05) rodents, 9.0% (95% CI = 5.71-13.28) domestic pigs, 4.7% (95% CI = 2.39-8.33) goats, and 3.2% (95% CI = 0.08-16.70) sheep were positive for IgG antibodies against Fra1 antigen of Y. pestis. On PCR, 8.4% (95% CI = 3.96-15.51) of the rodents were detected with Y. pestis pla gene, whereas all fleas were found negative. The common fleas identified were E. larina from pigs, whereas X. cheopis were the only fleas collected from rodents. The presence of sero-positive animals as well as the occurrence of X. cheopis on local rodents suggests that Y. pestis remains a risk in the district.


Asunto(s)
Monitoreo Epidemiológico/veterinaria , Infestaciones por Pulgas/veterinaria , Insectos Vectores/microbiología , Peste/microbiología , Enfermedades de los Roedores/epidemiología , Siphonaptera/microbiología , Yersinia pestis/aislamiento & purificación , Animales , Antígenos Bacterianos/sangre , Proteínas Bacterianas/sangre , Estudios Transversales , Ensayo de Inmunoadsorción Enzimática/veterinaria , Infestaciones por Pulgas/epidemiología , Infestaciones por Pulgas/parasitología , Ganado/microbiología , Peste/transmisión , Reacción en Cadena de la Polimerasa/veterinaria , Enfermedades de los Roedores/microbiología , Roedores , Zambia/epidemiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA