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1.
Res Vet Sci ; 164: 105030, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37788548

RESUMO

We describe the genetic diversity and phylogenetic relationships of Mycobacterium bovis, isolated from cattle in Malawi. Deletion analysis, spoligotyping, and MIRU-VNTR typing were used to genotype the isolates. Combined with a larger dataset from neighboring countries, the overall M. bovis diversity in Southern Africa was contextualized. From the southern and northern regions of Malawi, 24 isolates were confirmed as M. bovis. We pooled data for the central region (60 isolates) from our recent publication to conceptualize the genetic and phylogenetic relationships of M. bovis in Malawi. European 1 was the dominant M. bovis clonal complex, with 10 unique spoligotype patterns, and SB0131 was ubiquitous. High genetic diversity, a low clustering rate, and many singletons, coupled with a low mutation transmission index, infer a low level of recent transmission, and suggest an endemic status of bovine tuberculosis (bTB) in Malawi. M. bovis isolates from Zambia, Mozambique, and South Africa were genetically related to Malawian isolates, whereas Tanzanian isolates were distantly related. The diversity and phylogenetic analysis suggest earlier introductions and maintenance of M. bovis by constant reinfection from reservoir animals. These findings are fundamental to understanding the source and route of infection in order to establish alternative management strategies for bTB.


Assuntos
Doenças dos Bovinos , Mycobacterium bovis , Tuberculose Bovina , Animais , Bovinos , Mycobacterium bovis/genética , Malaui/epidemiologia , Filogenia , Variação Genética , Tuberculose Bovina/microbiologia , Genótipo , Repetições Minissatélites , Técnicas de Tipagem Bacteriana/veterinária , Doenças dos Bovinos/genética
2.
Sci Rep ; 13(1): 18165, 2023 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-37875565

RESUMO

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.


Assuntos
Arbovírus , Culicidae , Orthobunyavirus , Vírus de RNA , Animais , Humanos , Feminino , Mosquitos Vetores , Orthobunyavirus/genética , Vírus de RNA/genética , Arbovírus/genética
3.
Microorganisms ; 11(1)2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36677492

RESUMO

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.

4.
Virology ; 575: 10-19, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35987079

RESUMO

Nelson Bay orthoreovirus (NBV) is an emerging bat-borne virus and causes respiratory tract infections in humans sporadically. Over the last two decades, several strains genetically related to NBV were isolated from humans and various bat species, predominantly in Southeast Asia (SEA), suggesting a high prevalence of the NBV species in this region. In this study, an orthoreovirus (ORV) belonging to the NBV species was isolated from Indonesian fruit bats' feces, tentatively named Paguyaman orthoreovirus (PgORV). Serological studies revealed that 81.2% (108/133) of Indonesian fruit bats sera had neutralizing antibodies against PgORV. Whole-genome sequencing and phylogenetic analysis of PgORV suggested the occurrence of past reassortments with other NBV strains isolated in SEA, indicating the dispersal and circulation of NBV species among bats in this region. Intranasal PgORV inoculation of laboratory mice caused severe pneumonia. Our study characterized PgORV's unique genetic background and highlighted the potential risk of PgORV-related diseases in Indonesia.


Assuntos
Quirópteros , Orthoreovirus , Animais , Anticorpos Neutralizantes , Humanos , Indonésia/epidemiologia , Camundongos , Orthoreovirus/genética , Filogenia
5.
PLoS Negl Trop Dis ; 16(6): e0010420, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35653390

RESUMO

Rift valley fever (RVF) is a mosquito-borne disease of animals and humans. Although RVF outbreaks are usually reported at 5-15-year intervals in sub-Saharan Africa, Zambia has experienced an unusually long inter-epizootic/-epidemic period of more than three decades. However, serological evidence of RVF virus (RVFV) infection in domestic ruminants during this period underscores the need for comprehensive investigation of the mechanisms of virus perpetuation and disease emergence. Mosquitoes (n = 16,778) captured from eight of the ten provinces of Zambia between April 2014 and May 2019 were pooled (n = 961) and screened for RVFV genome by a pan-phlebo RT-PCR assay. Aedes mosquito pools (n = 85) were further screened by nested RT-PCR assay. Sera from sheep (n = 13), goats (n = 259) and wild ungulates (n = 285) were screened for RVFV antibodies by ELISA while genome detection in pooled sera (n = 276) from domestic (n = 248) and wild ungulates (n = 37) was performed by real-time RT-PCR assay. To examine the association between the long inter-epizootic period and climatic variables, we examined El Niño-Southern Oscillation indices, precipitation anomalies, and normalized difference vegetation index. We then derived RVF risk maps by exploring climatic variables that would favor emergence of primary RVFV vectors. While no RVFV genome could be detected in pooled mosquito and serum samples, seroprevalence was significantly high (OR = 8.13, 95% CI [4.63-14.25]) in wild ungulates (33.7%; 96/285) compared to domestic ruminants (5.6%; 16/272). Retrospective analysis of RVF epizootics in Zambia showed a positive correlation between anomalous precipitation (La Niña) and disease emergence. On risk mapping, whilst northern and eastern parts of the country were at high risk, domestic ruminant population density was low (< 21 animals/km2) in these areas compared to low risk areas (>21 animals/km2). Besides evidence of silent circulation of RVFV and the risk of disease emergence in some areas, wildlife may play a role in the maintenance of RVFV in Zambia.


Assuntos
Culicidae , Febre do Vale de Rift , Vírus da Febre do Vale do Rift , Animais , Anticorpos Antivirais , Surtos de Doenças/veterinária , Mosquitos Vetores , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Vírus da Febre do Vale do Rift/genética , Ruminantes , Estudos Soroepidemiológicos , Ovinos , Zâmbia/epidemiologia
6.
iScience ; 25(4): 104122, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35402872

RESUMO

The amino acid residue at position 333 of the rabies virus (RABV) glycoprotein (G333) is a major determinant of RABV pathogenicity. Virulent RABV strains possess Arg333, whereas the attenuated strain HEP-Flury (HEP) possesses Glu333. To investigate the potential attenuation mechanism dependent on a single amino acid at G333, comparative analysis was performed between HEP and HEP333R mutant with Arg333. We examined their respective tropism for astrocytes and the subsequent immune responses in astrocytes. Virus replication and subsequent interferon (IFN) responses in astrocytes infected with HEP were increased compared with HEP333R both in vitro and in vivo. Furthermore, involvement of IFN in the avirulency of HEP was demonstrated in IFN-receptor knockout mice. These results indicate that Glu333 contributes to RABV attenuation by determining the ability of the virus to infect astrocytes and stimulate subsequent IFN responses.

7.
Emerg Infect Dis ; 28(4): 888-890, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35318934

RESUMO

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


Assuntos
Leishmania infantum , Leishmaniose , Animais , Cães , Leishmaniose/veterinária , Doenças Negligenciadas , Probabilidade , Zâmbia/epidemiologia
8.
PLoS Negl Trop Dis ; 16(2): e0010193, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35120135

RESUMO

BACKGROUND: Although vector-borne zoonotic diseases are a major public health threat globally, they are usually neglected, especially among resource-constrained countries, including those in sub-Saharan Africa. This scoping review examined the current knowledge and identified research gaps of vector-borne zoonotic pathogens in Zambia. METHODS AND FINDINGS: Major scientific databases (Web of Science, PubMed, Scopus, Google Scholar, CABI, Scientific Information Database (SID)) were searched for articles describing vector-borne (mosquitoes, ticks, fleas and tsetse flies) zoonotic pathogens in Zambia. Several mosquito-borne arboviruses have been reported including Yellow fever, Ntaya, Mayaro, Dengue, Zika, West Nile, Chikungunya, Sindbis, and Rift Valley fever viruses. Flea-borne zoonotic pathogens reported include Yersinia pestis and Rickettsia felis. Trypanosoma sp. was the only tsetse fly-borne pathogen identified. Further, tick-borne zoonotic pathogens reported included Crimean-Congo Haemorrhagic fever virus, Rickettsia sp., Anaplasma sp., Ehrlichia sp., Borrelia sp., and Coxiella burnetii. CONCLUSIONS: This study revealed the presence of many vector-borne zoonotic pathogens circulating in vectors and animals in Zambia. Though reports of human clinical cases were limited, several serological studies provided considerable evidence of zoonotic transmission of vector-borne pathogens in humans. However, the disease burden in humans attributable to vector-borne zoonotic infections could not be ascertained from the available reports and this precludes the formulation of national policies that could help in the control and mitigation of the impact of these diseases in Zambia. Therefore, there is an urgent need to scale-up "One Health" research in emerging and re-emerging infectious diseases to enable the country to prepare for future epidemics, including pandemics.


Assuntos
Doenças Transmissíveis Emergentes , Doenças Transmitidas por Vetores/epidemiologia , Zoonoses/epidemiologia , Animais , Vetores Artrópodes , Bactérias , Humanos , Saúde Única , Trypanosoma , Vírus , Zâmbia/epidemiologia
9.
Transbound Emerg Dis ; 69(3): 1659-1662, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-33900037

RESUMO

Mycobacterium bovis (M. bovis) causes tuberculosis in mammals and is a major public health threat worldwide. While M. bovis has been reported in humans, domestic and wild ruminants at the human-wildlife-livestock interface area in Zambia, there is paucity of information on the role of primates as reservoir hosts. We screened seven wild chacma baboons (Papio ursinus) for tuberculosis at the human-wildlife interface area in Lochinvar National Park in the Kafue Flats, Zambia. Following necropsy, lung tissue and associated lymph nodes with tuberculous-like lesions collected from four adult male baboons were prepared for Mycobacterium culture. The isolates were initially typed using the Mycobacterium tuberculosis complex-discrimination multiplex PCR assay and further characterized by spoligotyping and 26-loci MIRU-VNTR. Mycobacteria were isolated from all four animals and identified as M. bovis by PCR. On Spoligotyping, all isolates belonged to SB 0120 spoligotype, which is similar to what was previously reported in humans, cattle and Kafue lechwe antelopes in Kafue Flats ecosystem. Furthermore, on MIRU-VNTR typing, the baboon isolates clustered with cattle and Kafue lechwe isolates from the same catchment area. This finding intimates probable cross-species transmission of M. bovis in the Kafue Flats ecosystem. Due to the close interaction of baboons and humans at interface areas in Zambia, our results have potential implications for public health. Equally, this finding raises concerns for conservation.


Assuntos
Antílopes , Doenças dos Bovinos , Mycobacterium bovis , Tuberculose Bovina , Tuberculose , Animais , Animais Selvagens/microbiologia , Bovinos , Ecossistema , Humanos , Masculino , Repetições Minissatélites , Papio ursinus , Tuberculose/epidemiologia , Tuberculose/microbiologia , Tuberculose/veterinária , Tuberculose Bovina/microbiologia , Zâmbia/epidemiologia
10.
Emerg Microbes Infect ; 10(1): 2169-2172, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34736356

RESUMO

While evidence suggests presence of HEV infection in humans in Zambia, currently, there is no information on its occurrence in domestic pigs. Here, we investigated the presence of HEV antibodies and genome in domestic pigs in Zambia. Sera (n = 484) from domestic pigs were screened for antibodies against HEV by ELISA while genome detection in fecal (n = 25) and liver (n = 100) samples from slaughter pigs was conducted using nested RT-PCR assay. Overall, seroprevalence was 47.7% (231/484) while zoonotic genotype 3 HEV RNA was detected in 16.0% (20/125) of slaughtered pigs. This is the first report to highlight occurrence of HEV infection in domestic pigs in Zambia. This finding suggests possible contamination of the pork supply chain. Moreover, there is a potential risk of zoonotic transmission of HEV to abattoir workers, pig farmers and handlers.


Assuntos
Vírus da Hepatite E/imunologia , Hepatite E/veterinária , Doenças dos Suínos/virologia , Matadouros , Animais , Anticorpos Anti-Hepatite/sangue , Hepatite E/sangue , Hepatite E/epidemiologia , Hepatite E/virologia , Vírus da Hepatite E/genética , Vírus da Hepatite E/isolamento & purificação , Estudos Soroepidemiológicos , Sus scrofa/sangue , Sus scrofa/virologia , Suínos , Doenças dos Suínos/sangue , Doenças dos Suínos/epidemiologia , Zâmbia/epidemiologia
11.
Pathogens ; 10(10)2021 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-34684256

RESUMO

Rickettsial pathogens are amongst the emerging and re-emerging vector-borne zoonoses of public health importance. Though traditionally considered to be transmitted by ixodid ticks, the role of argasid ticks as vectors of these pathogens is increasingly being recognized. While bat-feeding (Ornithodoros faini) and chicken-feeding (Argas walkerae) argasid ticks have been shown to harbor Rickettsia pathogens in Zambia, there are currently no reports of Rickettsia infection in southern Africa from warthog-feeding (Phacochoerus africanus) soft ticks, particularly Ornithodoros moubata and Ornithodoros porcinus. Our study sought to expand on the existing knowledge on the role of soft ticks in the epidemiology of Rickettsia species through screening for Rickettsia pathogens in warthog burrow-dwelling soft ticks from two national parks in Zambia. The tick species from which Rickettsia were detected in this study were identified as Ornithodoros porcinus, and an overall minimal Rickettsia infection rate of 19.8% (32/162) was observed. All of the sequenced Rickettsia were identified as Rickettsia lusitaniae based on nucleotide sequence similarity and phylogenetic analysis of the citrate synthase (gltA) and 17kDa common antigen (htrA) genes. Utilizing all of the gltA (n = 10) and htrA (n = 12) nucleotide sequences obtained in this study, BLAST analysis showed 100% nucleotide similarity to Rickettsia lusitaniae. Phylogenetic analysis revealed that all of the Zambian gltA and htrA gene sequences could be grouped with those of Rickettsia lusitaniae obtained in various parts of the world. Our data suggest that Rickettsia lusitaniae has a wider geographic and vector range, enhancing to our understanding of Rickettsia lusitaniae epidemiology in sub-Saharan Africa.

12.
mBio ; 12(4): e0141521, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34425707

RESUMO

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) possesses a discriminative polybasic cleavage motif in its spike protein that is recognized by the host furin protease. Proteolytic cleavage activates the spike protein, thereby affecting both the cellular entry pathway and cell tropism of SARS-CoV-2. Here, we investigated the impact of the furin cleavage site on viral growth and pathogenesis using a hamster animal model infected with SARS-CoV-2 variants bearing mutations at the furin cleavage site (S gene mutants). In the airway tissues of hamsters, the S gene mutants exhibited low growth properties. In contrast to parental pathogenic SARS-CoV-2, hamsters infected with the S gene mutants showed no body weight loss and only a mild inflammatory response, thereby indicating the attenuated variant nature of S gene mutants. This transient infection was sufficient for inducing protective neutralizing antibodies that cross-react with different SARS-CoV-2 lineages. Consequently, hamsters inoculated with S gene mutants showed resistance to subsequent infection with both the parental strain and the currently emerging SARS-CoV-2 variants belonging to lineages B.1.1.7 and P.1. Taken together, our findings revealed that the loss of the furin cleavage site causes attenuation in the airway tissues of hamsters and highlighted the potential benefits of S gene mutants as potential immunogens. IMPORTANCE SARS-CoV-2 uses its spike protein to enter target cells. The spike protein is cleaved by a host protease, and this event facilitates viral entry and broadens cell tropism. In this study, we employed SARS-CoV-2 mutants lacking the S protein cleavage site and characterized their growth and pathogenicity using hamsters, a laboratory animal model for SARS-CoV-2 infection. These mutants exerted low pathogenicity but induced sufficient levels of neutralizing antibodies in hamsters, which protected hamsters from rechallenge with pathogenic clinical SARS-CoV-2 strains. These virus mutants may be used as protective immunogens against SARS-CoV-2 infection.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/patologia , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/genética , Animais , Linhagem Celular , Chlorocebus aethiops , Reações Cruzadas/imunologia , Furina/metabolismo , Humanos , SARS-CoV-2/genética , SARS-CoV-2/imunologia , SARS-CoV-2/patogenicidade , Vacinas Atenuadas/imunologia , Células Vero , Virulência/genética
13.
Pathogens ; 10(6)2021 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-34208340

RESUMO

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.

14.
PLoS Negl Trop Dis ; 15(4): e0009222, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33909621

RESUMO

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.


Assuntos
Doenças do Cão/prevenção & controle , Vacina Antirrábica/imunologia , Raiva/veterinária , Cobertura Vacinal/estatística & dados numéricos , Animais , Teorema de Bayes , Estudos Transversais , Cães , Feminino , Masculino , Vacinação em Massa/veterinária , Propriedade , Raiva/prevenção & controle , Vacina Antirrábica/administração & dosagem , População Rural , Zâmbia
15.
Arch Virol ; 166(3): 915-919, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33475831

RESUMO

Tick-borne pathogens are an emerging public health threat worldwide. However, information on tick-borne viruses is scanty in sub-Saharan Africa. Here, by RT-PCR, 363 ticks (Amblyomma, Hyalomma and Rhipicephalus) in the Namwala and Livingstone districts of Zambia were screened for tick-borne phleboviruses (TBPVs). TBPVs (L gene) were detected in 19 (5.2%) Rhipicephalus ticks in Namwala. All the detected TBPVs were Shibuyunji viruses. Phylogenetically, they were closely related to American dog tick phlebovirus. This study highlights the possible role of Rhipicephalus ticks as the main host of Shibuyunji virus and suggests that these viruses may be present outside the area where they were initially discovered.


Assuntos
Amblyomma/virologia , Febre por Flebótomos/epidemiologia , Phlebovirus/isolamento & purificação , Rhipicephalus/virologia , Doenças Transmitidas por Carrapatos/epidemiologia , Animais , Variação Genética/genética , Febre por Flebótomos/transmissão , Febre por Flebótomos/virologia , Phlebovirus/genética , Filogenia , Prevalência , Análise de Sequência de DNA , Doenças Transmitidas por Carrapatos/virologia , Zâmbia/epidemiologia
16.
Viruses ; 12(9)2020 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-32878170

RESUMO

Bluetongue (BT) is an arthropod-borne viral disease of ruminants with serious trade and socio-economic implications. Although the disease has been reported in a number of countries in sub-Saharan Africa, there is currently no information on circulating serotypes and disease distribution in Zambia. Following surveillance for BT in domestic and wild ruminants in Zambia, BT virus (BTV) nucleic acid and antibodies were detected in eight of the 10 provinces of the country. About 40% (87/215) of pooled blood samples from cattle and goats were positive for BTV nucleic acid, while one hartebeest pool (1/43) was positive among wildlife samples. Sequence analysis of segment 2 revealed presence of serotypes 3, 5, 7, 12 and 15, with five nucleotypes (B, E, F, G and J) being identified. Segment 10 phylogeny showed Zambian BTV sequences clustering with Western topotype strains from South Africa, intimating likely transboundary spread of BTV in Southern Africa. Interestingly, two Zambian viruses and one isolate from Israel formed a novel clade, which we designated as Western topotype 4. The high seroprevalence (96.2%) in cattle from Lusaka and Central provinces and co-circulation of multiple serotypes showed that BT is widespread, underscoring the need for prevention and control strategies.


Assuntos
Vírus Bluetongue/isolamento & purificação , Bluetongue/virologia , Doenças dos Bovinos/virologia , Doenças das Cabras/virologia , Doenças dos Ovinos/virologia , Animais , Bluetongue/epidemiologia , Vírus Bluetongue/classificação , Vírus Bluetongue/genética , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças das Cabras/epidemiologia , Cabras , Filogenia , Ovinos , Doenças dos Ovinos/epidemiologia , Zâmbia/epidemiologia
17.
Transbound Emerg Dis ; 67(6): 2741-2752, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32434281

RESUMO

African swine fever (ASF) causes persistent outbreaks in endemic and non-endemic regions in Zambia. However, the epidemiology of the disease is poorly understood, particularly during the inter-epidemic periods. We conducted surveillance for ASF in asymptomatic domestic pigs and soft ticks in selected Zambian provinces. While serum samples (n = 1,134) were collected from crossbred pigs from all study sites between 2014 and 2017, whole blood (n = 300) was collected from both crossbred and indigenous pigs in Eastern Province (EP) in 2017. Soft ticks were collected from Mosi-oa-Tunya National Park in Southern Province (SP) in 2019. Sera were screened for antibodies against ASF by ELISA while genome detection in whole blood and soft ticks was conducted by PCR. Ticks were identified morphologically and by phylogenetic analysis of the 16S rRNA gene. Seroprevalence was highest in EP (50.9%, 95% CI [47.0-54.9]) compared to significantly lower rates in SP (2.9%, 95% CI [1.6-5.1]). No antibodies to ASFV were detected in Lusaka Province. In EP, the prevalence of ASFV genome was 11.7% (35/300), significantly higher (OR = 6.2, 95% CI [2.4-16.6]) in indigenous pigs compared to crossbred pigs. The pooled prevalence of ASFV genome in ticks was 11.0%, 95% CI [8.5-13.9]. Free-range husbandry system was the only factor that was significantly associated with seropositive (p < .0001, OR = 39.3) and PCR-positive results (p < .001, OR = 5.7). Phylogenetically, based on the p72 gene, ASFV from Ornithodoros moubata ticks detected in this study belonged to genotype I, but they separated into two distinct clusters. Besides confirming ASF endemicity in EP and the presence of ASFV-infected ticks in SP, these results provide evidence for exposure of domestic pigs to ASFV in non-endemic regions during the inter-epidemic period.


Assuntos
Vírus da Febre Suína Africana/fisiologia , Febre Suína Africana/epidemiologia , Argasidae/virologia , Infecções Assintomáticas/epidemiologia , Epidemias/veterinária , Monitoramento Epidemiológico/veterinária , Febre Suína Africana/virologia , Animais , Prevalência , Estudos Soroepidemiológicos , Sus scrofa , Suínos , Zâmbia/epidemiologia
18.
Emerg Infect Dis ; 26(4): 811-814, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32187004

RESUMO

We detected West Nile virus (WNV) nucleic acid in crocodiles (Crocodylus niloticus) in Zambia. Phylogenetically, the virus belonged to lineage 1a, which is predominant in the Northern Hemisphere. These data provide evidence that WNV is circulating in crocodiles in Africa and increases the risk for animal and human transmission.


Assuntos
Jacarés e Crocodilos , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Humanos , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental/genética , Zâmbia/epidemiologia
19.
Arch Virol ; 164(10): 2531-2536, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31300890

RESUMO

Whilst bovine leukemia virus (BLV) causes considerable economic losses to the dairy industry worldwide, information on its molecular epidemiology and economic impact in beef cattle is limited. Here, blood from 880 animals from Zambia's major cattle-rearing provinces was screened for BLV by nested PCR. Positive pools were sequenced and phylogenetically analyzed. The estimated pooled prevalence was 2.1%. All strains belonged to genotype 1 and formed a distinct phylogenetic cluster. The study suggests circulation of genotype 1 BLV in beef cattle in these regions. This is the first report on molecular detection and characterization of BLV from beef cattle in Africa.


Assuntos
Leucose Enzoótica Bovina/epidemiologia , Leucose Enzoótica Bovina/virologia , Genótipo , Vírus da Leucemia Bovina/genética , Vírus da Leucemia Bovina/isolamento & purificação , Animais , Bovinos , Vírus da Leucemia Bovina/classificação , Epidemiologia Molecular , Filogenia , Reação em Cadeia da Polimerase , Prevalência , Análise de Sequência de DNA , Zâmbia/epidemiologia
20.
Onderstepoort J Vet Res ; 85(1): e1-e5, 2018 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-30035596

RESUMO

African swine fever (ASF) is a contagious haemorrhagic disease associated with causing heavy economic losses to the swine industry in many African countries. In 2017, Zambia experienced ASF outbreaks in Mbala District (Northern province) and for the first time in Isoka and Chinsali districts (Muchinga province). Meanwhile, another outbreak was observed in Chipata District (Eastern province). Genetic analysis of part of the B646L gene, E183L gene, CP204L gene and the central variable region of the B602L gene of ASF virus (ASFV) associated with the outbreaks in Mbala and Chipata districts was conducted. The results revealed that the ASFV detected in Mbala District was highly similar to that of the Georgia 2007/1 isolate across all the genome regions analysed. In contrast, while showing close relationship with the Georgia 2007/1 virus in the B646L gene, the ASFV detected in Chipata District showed remarkable genetic variation in the rest of the genes analysed. These results suggest that the Georgia 2007/1-like virus could be more diverse than what was previously thought, underscoring the need of continued surveillance and monitoring of ASFVs within the south-eastern African region to better understand their epidemiology and the relationships between outbreaks and their possible origin.


Assuntos
Vírus da Febre Suína Africana/genética , Febre Suína Africana/epidemiologia , Surtos de Doenças/veterinária , Variação Genética , Genótipo , Febre Suína Africana/virologia , Animais , Filogenia , Análise de Sequência de DNA/veterinária , Sus scrofa , Suínos , Zâmbia/epidemiologia
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