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1.
Int J Mol Sci ; 23(5)2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35269976

RESUMO

Bacteriocins are emerging as a viable alternative to antibiotics due to their ability to inhibit growth or kill antibiotic resistant pathogens. Herein, we evaluated the ability of the bacteriocin Garvicin KS (GarKS) produced by Lactococcus garvieae KS1546 isolated from cow milk to inhibit the growth of fish and foodborne bacterial pathogens. We found that GarKS inhibited the growth of five fish L. garvieae strains isolated from infected trout and eels. Among fish pathogens, GarKS inhibited the growth of Streptococcus agalactiae serotypes Ia and Ib, and Aeromonas hydrophila but did not inhibit the growth of Edwardsiella tarda. In addition, it inhibited the growth of A. salmonicida strain 6421 but not A. salmonicida strain 6422 and Yersinia ruckeri. There was no inhibition of three foodborne bacterial species, namely Salmonella enterica, Klebsiella pneumoniae, and Escherichia coli. In vitro cytotoxicity tests using different GarKS concentrations showed that the highest concentration of 33 µg/mL exhibited low cytotoxicity, while concentrations ≤3.3 µg/mL had no cytotoxicity on CHSE-214 and RTG-2 cells. In vivo tests showed that zebrafish larvae treated with 33 µg/mL and 3.3 µg/mL GarKS prior to challenge had 53% and 48% survival, respectively, while concentrations ≤0.33 µg/mL were nonprotective. Altogether, these data show that GarKS has a broad inhibitory spectrum against Gram positive and negative bacteria and that it has potential applications as a therapeutic agent for a wide range of bacterial pathogens. Thus, future studies should include clinical trials to test the efficacy of GarKS against various bacterial pathogens in farmed fish.


Assuntos
Bacteriocinas , Doenças dos Peixes , Yersiniose , Animais , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Bovinos , Feminino , Doenças dos Peixes/tratamento farmacológico , Doenças dos Peixes/microbiologia , Doenças dos Peixes/prevenção & controle , Lactococcus , Larva , Peixe-Zebra
2.
J Aquat Anim Health ; 33(3): 162-177, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34121243

RESUMO

Tilapia culture is a very promising industry within the aquaculture sector. However, disease outbreaks have continued to threaten the industry, causing serious economic losses among the producers. Streptococcosis has become the major bacterial disease affecting tilapia production in most regions of the world. To combat the disease and minimize its economic impact on fish producers, numerous preventive and control measures have been developed and reported over the years. This paper aims to systematically review the measures that could be used to manage the disease outbreaks and maintain fish health based on previously published scientific studies. Although numerous measures currently available have been highlighted, it is far better for the producers to maximize the preventive measures for management to be economically feasible. Among the currently available preventive measures, the use of vaccines has been shown to have the most promise, while the use of herbs has been demonstrated to be a more sustainable and economically affordable control measure. However, there are still a number of important gaps in existing literature that require further investigation. Overall, significant progress has been made in preventing and controlling streptococcosis in tilapia although, no single effective measure has been identified. Therefore, a combination of these measures may provide a more effective result.


Assuntos
Doenças dos Peixes , Infecções Estreptocócicas , Tilápia , Animais , Aquicultura , Doenças dos Peixes/prevenção & controle , Infecções Estreptocócicas/prevenção & controle , Infecções Estreptocócicas/veterinária
3.
Trop Anim Health Prod ; 44(7): 1593-8, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22367736

RESUMO

Owing to frequent reports of suspected outbreaks and the presence of reservoir hosts and vectors (warthogs, bushpigs and O. moubata ticks), African swine fever (ASF) is believed to be an endemic disease in Uganda. There have, however, been very few studies carried out to confirm its existence in Uganda. This study was carried out to describe the prevalence of ASF based on pathologic lesions and analysis of serum samples from slaughtered pigs during a suspected outbreak in the Mubende district of Uganda. The study was based on visits to 22 slaughterhouses where individual pigs were randomly selected for a detailed ante-mortem and post-mortem inspections. Sera were also collected for laboratory analysis. A total of 997 pigs (53.7% male and 46.3% female) were examined for lesions suggestive of ASF and sero-positivity of sera for ASF antibodies. The sera were tested using enzyme-linked immunosorbent assay (ELISA) and positive samples were further confirmed with an immunoblot assay. The results showed that 3.8% (38/997) of the pigs examined had clinical signs and post-mortem lesions suggestive of ASF. Two of 997 (0.2%) sera analysed were positive for ASF antibodies. Of the sub-counties investigated, Bagezza (12%) and Kiyuni (11%) had the highest prevalence of lesions suggestive of ASF based on ante- and post-mortem examination results, while Mubende town council (1.7%) had the lowest. This study found a low number of pigs (3.8%) with lesions suggestive of ASF at slaughter and an even lower number of pigs (0.2%) that were seropositive at slaughter, however a significantly higher number of pigs were slaughtered during the outbreak as a strategy for farmers to avoid losses associated with mortality.


Assuntos
Vírus da Febre Suína Africana/isolamento & purificação , Febre Suína Africana/epidemiologia , Anticorpos Antivirais/sangue , Surtos de Doenças/veterinária , Matadouros , Febre Suína Africana/virologia , Animais , Autopsia/veterinária , Estudos Transversais , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Immunoblotting/veterinária , Modelos Logísticos , Masculino , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Suínos , Uganda/epidemiologia
4.
Rev Biol Trop ; 60(4): 1631-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23342517

RESUMO

Black lechwe (Kobus leche smithemani) is a semi-aquatic medium sized antelope currently enlisted on the IUCN red list of endangered species and is only endemic to the Bangweulu basin of Zambia. Its population has significantly decreased due to floods that took place during the period 1930-1940 from over 250 000-15000 leading the Zambian government to gazette all habitats of Black lechwe into state protected areas, and to establish urgent management strategies needed to save the remaining population from extinction. Using retrospective data, our findings show that the population has increased from 15000 animals in 1954 to 55 632 in 2009. The current population is estimated at 34.77% (55 632/160 000) of the carrying capacity of the Bangweulu basin. Although the Black lechwe is one of the 42 species offered for consumptive utilization by the Zambia Wildlife Authority (ZAWA), only 0.12% and 0.08% of the current stock was offered for safari and resident hunting annually for the period 2005-2009, respectively. Annual quota utilization were estimated at 67% (n=37) and 81% (n=37) for safari and resident hunting, respectively. Hence, overall income obtained from utilization of Black lechwe is very low accounting for only 2.1% of the total revenue earned from wildlife utilization. Although the current population trend is showing a unit increase of 639 animals per year, it is still far below levels ideal for the lucrative utilization. In this study, we demonstrate that adverse ecological changes on wildlife species, can lead to their vulnerability and danger of extinction, and that their recovery to full carrying capacity may demand a considerable amount of time.


Assuntos
Antílopes/classificação , Ecossistema , Espécies em Perigo de Extinção , Animais , Conservação dos Recursos Naturais/métodos , Conservação dos Recursos Naturais/estatística & dados numéricos , Monitoramento Ambiental , Extinção Biológica , Densidade Demográfica , Zâmbia
5.
Front Microbiol ; 13: 1008870, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36532495

RESUMO

Aeromonas species are Gram-negative bacteria that infect various living organisms and are ubiquitously found in different aquatic environments. In this study, we used whole genome sequencing (WGS) to identify and compare the antimicrobial resistance (AMR) genes, integrons, transposases and plasmids found in Aeromonas hydrophila, Aeromonas caviae and Aeromonas veronii isolated from Indian major carp (Catla catla), Indian carp (Labeo rohita), catfish (Clarias batrachus) and Nile tilapia (Oreochromis niloticus) sampled in India. To gain a wider comparison, we included 11 whole genome sequences of Aeromonas spp. from different host species in India deposited in the National Center for Biotechnology Information (NCBI). Our findings show that all 15 Aeromonas sequences examined had multiple AMR genes of which the Ambler classes B, C and D ß-lactamase genes were the most dominant. The high similarity of AMR genes in the Aeromonas sequences obtained from different host species point to interspecies transmission of AMR genes. Our findings also show that all Aeromonas sequences examined encoded several multidrug efflux-pump proteins. As for genes linked to mobile genetic elements (MBE), only the class I integrase was detected from two fish isolates, while all transposases detected belonged to the insertion sequence (IS) family. Only seven of the 15 Aeromonas sequences examined had plasmids and none of the plasmids encoded AMR genes. In summary, our findings show that Aeromonas spp. isolated from different host species in India carry multiple AMR genes. Thus, we advocate that the control of AMR caused by Aeromonas spp. in India should be based on a One Health approach.

6.
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
7.
Pathogens ; 10(6)2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-34070735

RESUMO

Aquaculture is the fastest food-producing sector in the world, accounting for one-third of global food production. As is the case with all intensive farming systems, increase in infectious diseases has adversely impacted the growth of marine fish farming worldwide. Viral diseases cause high economic losses in marine aquaculture. We provide an overview of the major challenges limiting the control and prevention of viral diseases in marine fish farming, as well as highlight potential solutions. The major challenges include increase in the number of emerging viral diseases, wild reservoirs, migratory species, anthropogenic activities, limitations in diagnostic tools and expertise, transportation of virus contaminated ballast water, and international trade. The proposed solutions to these problems include developing biosecurity policies at global and national levels, implementation of biosecurity measures, vaccine development, use of antiviral drugs and probiotics to combat viral infections, selective breeding of disease-resistant fish, use of improved diagnostic tools, disease surveillance, as well as promoting the use of good husbandry and management practices. A multifaceted approach combining several control strategies would provide more effective long-lasting solutions to reduction in viral infections in marine aquaculture than using a single disease control approach like vaccination alone.

8.
BMC Res Notes ; 14(1): 313, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34399833

RESUMO

OBJECTIVES: Aeromonads cause severe diseases in farmed aquatic organisms. Herein, we examined 28 isolates causing disease in farmed aquatic organisms from India (n = 24) and Taiwan (n = 4) to gain insight of their genotypic and phenotypic properties. RESULTS: API 20NE biochemical phenotyping showed ≥ 90% similarity classifying all isolates as Aeromonas hydrophila. 16S rRNA genotyping showed ≥ 98% homology among all isolates with A. sobria (NR119044.1ATCC), A. veronii (MK990549.1), A. caviae (NR029252.1) and A. hydrophila (MG984625.1ATCC) and other reference strains. In contrast, gyrB showed a higher intraspecies diversity (≥ 96%) than 16S rRNA delineating the 28 isolates into three groups. Group-I consisted of seven Indian isolates clustered with A. sobria (MK484163.1ATCC), group-II comprised of five Indian and two Taiwanese isolates clustered with A. veronii AF417626.1ATCC while group-III had 11 Indian and three Taiwanese isolates grouped with A. hydrophila (AY987520.1 and DQ519366.1) reference strains. None of our isolates clustered with A. caviae (AJ868400.1ATCC) reference strain. These findings suggest that A. sobria, A. veronii and A. hydrophila could be the etiological agents of diseases observed in farmed fish and soft-shelled turtles (Pelodiscus sinensis) examined in this study. Overall, our findings accentuate the importance of combining phenotyping with genotyping for correct taxonomic classification of Aeromonas spp. in Aquaculture.


Assuntos
Aeromonas , Aeromonas/genética , Aeromonas hydrophila/genética , Animais , Índia , RNA Ribossômico 16S/genética , Taiwan
9.
BMC Vet Res ; 6: 21, 2010 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-20406464

RESUMO

BACKGROUND: Awareness of bovine tuberculosis (BTB) by cattle owners is of extreme importance to policy makers when considering mitigation. However, to our knowledge, little is known on cattle owners' awareness of BTB in Zambia. Similarly, such knowledge is uncommon within and outside Africa. The current study investigates the epidemiological characteristics of BTB in Zambian cattle in relation to awareness by cattle owners in high and low cattle BTB prevalence settings. A cross sectional study was designed and data was gathered based on 106 cattle owners and cattle herds; subjected to an interviewer-administered questionnaire and comparative intradermal tuberculin test using a cut-off for positivity of 4 mm, respectively. RESULTS: Reported levels of cattle and wildlife contact by respondents was at 40%, 58.2% and 1.8%, were relatively proportional to herd level prevalence of cattle BTB at 64.8%, 58.1% and 5.9% in Blue lagoon, Lochinvar and Kazungula respectively. Although 42/106 (39.6%) of cattle owners had heard of BTB, only 3 (7%) had an idea on how the disease was spread. Cattle contact with wildlife was associated with high levels of awareness by cattle owners (chi2 = 43.5, df = 2, P < 0.001). Awareness of BTB in low prevalence settings was lower compared to high prevalence settings. CONCLUSIONS: Our study has revealed low levels of awareness among cattle owners on BTB. These results could be useful for policy makers when planning mitigation measures to consider awareness levels by cattle owners for effective implementation. Such information is useful for determining sensitisation programs for cattle owners before mitigation. These results further provide useful insights that disease control is a multi-factorial process with cattle owners as an integral part that can support policy implementation.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Tuberculose Bovina/epidemiologia , Tuberculose Bovina/transmissão , Criação de Animais Domésticos , Animais , Animais Selvagens , Bovinos , Coleta de Dados , Prevalência , Zâmbia/epidemiologia
10.
BMC Vet Res ; 6: 29, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20515454

RESUMO

BACKGROUND: In Zambia, translocation of wildlife from National Parks to private owned game ranches demands that only animals free of infectious diseases that could adversely affect the expansion of the wildlife industry should be translocated to game ranches. Sarcoptes mange (Sarcoptes scarbiei) has been involved in the reduction of wildlife populations in some species. RESULTS: Sarcoptes mange (Sarcoptes scarbiei) was detected and eradicated from two herds of African buffalo (Syncerus caffer) calves captured in the Kafue GMA in July 2004 and August 2005. The overall prevalence was estimated at 89.5% (77/86). Sex had no influence on the occurrence and severity of the disease. Of the 86 calves used in the study, 72.1% had good body condition scores, 20.9% were fair and 7.0% were poor. Of the 77 infected calves, 53.2% were mildly infected, 28.6% were moderately and 18.2% were severely infected. Body condition score was correlated to the severity of the infection (r = 0.72, p < 0.000, n = 86) at capture. Eradication of Sarcoptes mites from the entire herd using ivermetcin was dependant on the severity of the infection. The overall ability of ivermectin to clear the infection after the first treatment was estimated at 81.8% (n = 77). It increased to 94.8% and 100% after the second and third treatments respectively. CONCLUSION: This is the first report on the epidemiology and treatment of Sarcoptes mange in African buffaloes in Zambia. This study improves our understanding about Sarcoptes scabiei epidemiology and treatment which will have further applications for the safe animal translocation.


Assuntos
Búfalos , Inseticidas/uso terapêutico , Ivermectina/uso terapêutico , Sarcoptes scabiei , Escabiose/veterinária , Animais , Composição Corporal , Feminino , Masculino , Prevalência , Escabiose/epidemiologia , Zâmbia/epidemiologia
11.
Viruses ; 13(1)2020 12 25.
Artigo em Inglês | MEDLINE | ID: mdl-33375689

RESUMO

Viral hemorrhagic septicemia virus (VHSV) is a highly pathogenic virus that infects a wide range of host fish species causing high economic losses in aquaculture. Epithelial cells in mucosal organs are target sites for VHSV entry into fish. To protect fish against VHSV infection, there is a need to develop antiviral compounds able to prevent establishment of infection at portals of virus entry into fish. Bacillus subtilis is a probiotic with excellent antiviral properties, of which one of its secretions, surfactin, has been shown to inhibit viral infections in mammals. Herein, we demonstrate its ability to prevent VHSV infection in olive flounder (Paralichthys olivaceus) intestinal epithelial cells (IECs) and infection in internal organs. Our findings show inhibition of VHSV infection in IECs by B. subtilis and surfactin. In addition, our findings showed inhibition of VHSV in Epithelioma Papulosum Cyprini (EPC) cells inoculated with intestinal homogenates from the fish pretreated with B. subtilis by oral exposure, while the untreated fish had cytopathic effects (CPE) caused by VHSV infection in the intestines at 48 h after the VHSV challenge. At 96 h post-challenge, samples from the untreated fish had CPE from head kidney and spleen homogenates and no CPE were observed in the intestinal homogenates, while the B. subtilis-pretreated fish had no CPE in all organs. These findings demonstrate that inhibition of VHSV infection at portals of virus entry in the intestines culminated in prevention of infection in internal organs. In summary, our results show that B. subtilis has the potential to prevent VHSV infection in fish and that its use as a probiotic in aquaculture has the potential to serve as an antiviral therapeutic agent against different viral infections.


Assuntos
Antibiose , Bacillus subtilis/fisiologia , Células Epiteliais/virologia , Doenças dos Peixes/virologia , Linguado/virologia , Mucosa Intestinal/virologia , Infecções por Rhabdoviridae/veterinária , Animais , Células Cultivadas , Novirhabdovirus
12.
Sci Rep ; 10(1): 20364, 2020 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-33230226

RESUMO

Tilapia lake virus (TiLV) causes high mortality and high economic losses in tilapines. We describe an experimental challenge study focusing on early post challenge innate immune responses. Nile tilapia (Oreochromis niloticus) were infected with 105 TCID50/mL TiLV intraperitoneally, followed by virus quantification, histopathology and gene expression analysis in target (brain/liver) and lymphoid (spleen/headkidney) organs at 3, 7, 12, 17, and 34 days post challenge (dpc). Onset of mortality was from 21 dpc, and cumulative mortality was 38.5% by 34 dpc. Liver and kidney histopathology developed over the period 3-17 dpc, characterized by anisocytosis, anisokaryocytosis, and formation of multinucleated hepatocytes. Viral loads were highest at early time (3 dpc) in liver, spleen and kidney, declining towards 34 dpc. In brain, viral titer peaked 17 dpc. Innate sensors, TLRs 3/7 were inversely correlated with virus titer in brain and headkidney, and IFN-ß and Mx showed a similar pattern. All organs showed increased mRNA IgM expression over the course of infection. Overall, high virus titers downplay innate responses, and an increase is seen when viral titers decline. In silico modeling found that TiLV segments 4, 5 and 10 carry nucleolar localization signals. Anti-viral effects of TiLV facilitate production of virus at early stage of infection.


Assuntos
Ciclídeos/imunologia , Doenças dos Peixes/imunologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata , Vírus de RNA de Sentido Negativo/patogenicidade , Animais , Anticorpos Antivirais/biossíntese , Anticorpos Antivirais/genética , Encéfalo/imunologia , Encéfalo/virologia , Ciclídeos/virologia , Doenças dos Peixes/mortalidade , Doenças dos Peixes/patologia , Doenças dos Peixes/virologia , Regulação da Expressão Gênica , Hepatócitos/imunologia , Hepatócitos/virologia , Imunoglobulina M/biossíntese , Imunoglobulina M/genética , Interferon beta/genética , Interferon beta/imunologia , Rim/imunologia , Rim/virologia , Fígado/imunologia , Fígado/virologia , Vírus de RNA de Sentido Negativo/crescimento & desenvolvimento , Vírus de RNA de Sentido Negativo/imunologia , Baço/imunologia , Baço/virologia , Análise de Sobrevida , Fatores de Tempo , Receptor 3 Toll-Like/genética , Receptor 3 Toll-Like/imunologia , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/imunologia
13.
PLoS One ; 15(3): e0230739, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32214386

RESUMO

The autovaccine was produced in-house using a bacterial isolate from a diseased fish from the target farm. Three groups of 150 fish each were injected with either 1) an oil-adjuvanted, inactivated whole cell autovaccine, 2) adjuvant only or 3) PBS (negative control). Approximately 660 degree days post vaccination, the fish were challenged with 9x105 cfu bacteria/fish by intraperitoneal injection and monitored for a further 28 days. Protection against infections was measured by lack of/reduced bacterial loads both by bacterial re-isolation and immunohistochemistry as well as absence of clinical signs/pathology. Significantly less L. garvieae (p<0.03) was re-isolated from either the adjuvant only or control groups compared to the vaccinated group. Furthermore, a significantly high amount (p<0.001) of anti-L. garvieae specific antibodies were observed in the vaccinated group compared to the adjuvant only or control groups at time of challenge. This coincided with protection against infection measured by absence/reduced L. garvieae re-isolation from internal organs, reduced clinical signs and lack of pathology in this group. In the adjuvant only and control groups, bacteria were re-isolated from the kidney, liver, spleen, brain and eyes during the first 14 days. The findings suggest that oil-based vaccines can protect tilapia against L. garvieae infection through an antibody mediated response.


Assuntos
Autovacinas/imunologia , Ciclídeos/imunologia , Ciclídeos/microbiologia , Doenças dos Peixes/prevenção & controle , Lactococcus/fisiologia , Animais , Autopsia , Doenças dos Peixes/patologia , Especificidade de Órgãos
14.
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
16.
Viruses ; 11(10)2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31554184

RESUMO

Tilapia is the second most farmed fish species after carp in the world. However, the production has come under threat due to emerging diseases such as tilapia lake virus (TiLV) that causes massive mortalities with high economic losses. It is largely unknown whether different tilapia strains are equally susceptible to TiLV infection. In the present study we compared the susceptibility of gray (Oreochromis niloticus x O. aureus) and red tilapia (Oreochromis spp.) to experimental TiLV infection. Virus was injected intraperitoneally at a concentration of 104 TCID50/mL. Our findings show that gray tilapia had a lower mortality, 86.44%, but statistically not significantly different (p = 0.068) from red tilapia (100%). The duration of the mortality period from onset to cessation was similar for the two species, starting at 2-3 days post challenge (dpc) with a median at 10-11 dpi and ending on 20-22 dpi. In addition, there was no difference between species in mean viral loads in brain, liver and headkidney from fish collected soon after death. As for host response, expression levels of IL-1ß and TNFα were equally high in brain and headkidney samples while levels in liver samples were low for both red and gray tilapia, which coincides with lower viral loads in liver compared to brain and headkidney for both species. We find that red and gray tilapia were equally susceptible to TiLV infection with similar post challenge mortality levels, equal virus concentration in target organs and similar proinflammatory cytokine responses in target and lymphoid organs at time of death. Nonetheless, we advocate that the search for less susceptible tilapia strains should continue with the view to reduce losses from TiLV infection in aquaculture.


Assuntos
Doenças dos Peixes/virologia , Vírus de RNA/patogenicidade , Tilápia/virologia , Animais , Aquicultura , Citocinas/genética , Suscetibilidade a Doenças , Doenças dos Peixes/imunologia , Doenças dos Peixes/mortalidade , Expressão Gênica , Análise de Sobrevida , Carga Viral
17.
Front Microbiol ; 8: 406, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28382024

RESUMO

The global expansion of the aquaculture industry has brought with it a corresponding increase of novel viruses infecting different aquatic organisms. These emerging viral pathogens have proved to be a challenge to the use of traditional cell-cultures and immunoassays for identification of new viruses especially in situations where the novel viruses are unculturable and no antibodies exist for their identification. Viral metagenomics has the potential to identify novel viruses without prior knowledge of their genomic sequence data and may provide a solution for the study of unculturable viruses. This review provides a synopsis on the contribution of viral metagenomics to the discovery of viruses infecting different aquatic organisms as well as its potential role in viral diagnostics. High throughput Next Generation sequencing (NGS) and library construction used in metagenomic projects have simplified the task of generating complete viral genomes unlike the challenge faced in traditional methods that use multiple primers targeted at different segments and VPs to generate the entire genome of a novel virus. In terms of diagnostics, studies carried out this far show that viral metagenomics has the potential to serve as a multifaceted tool able to study and identify etiological agents of single infections, co-infections, tissue tropism, profiling viral infections of different aquatic organisms, epidemiological monitoring of disease prevalence, evolutionary phylogenetic analyses, and the study of genomic diversity in quasispecies viruses. With sequencing technologies and bioinformatics analytical tools becoming cheaper and easier, we anticipate that metagenomics will soon become a routine tool for the discovery, study, and identification of novel pathogens including viruses to enable timely disease control for emerging diseases in aquaculture.

18.
Jpn J Vet Res ; 54(1): 3-13, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16786973

RESUMO

Eco-tourism depending on wildlife is becoming increasingly profitable and landowners are beginning to favor game farming and ecotourism. In these areas, large-scale translocation of wildlife involves a diversity of species and large populations. The African buffalo (Syncerus caffer) is one of the major tourist attractions in Zambia. It accounts for 8.7% and 12.4% of the total animal species hunted in the Game Management Areas and the total hunting revenue earned in Zambia, respectively. It is ecologically an important animal species essential for the purpose of habitat control and facilitating the provision of suitable grazing pastures. However, the rearing of the African buffalo on game ranches has been hampered by its carrier state of the Southern Africa Terroritory (SAT) serotypes of foot and mouth disease virus (FMD). The African buffalo is also known to be a carrier of Theileria parva lawrencei, the causative agent of corridor disease (CD) that continues to have devastating effects on the livestock industry in Zambia. In addition, the importation of buffaloes from countries with populations endemic to bovine tuberculosis is highly restricted. Veterinary regulations in Zambia, strongly advocate against the translocation of buffaloes from protected areas to private ranches for disease control purposes thereby mounting a considerable constraint on the economic and ecological viability of the industry. It is hoped that this review will motivate the relevant government authorities in exploiting ways in which this animal species play a central role in eco-tourism.


Assuntos
Búfalos/parasitologia , Búfalos/virologia , Portador Sadio/veterinária , Animais , Brucelose/epidemiologia , Brucelose/veterinária , Portador Sadio/parasitologia , Portador Sadio/virologia , Conservação dos Recursos Naturais , Febre Aftosa/epidemiologia , Theileriose/epidemiologia , Tuberculose/epidemiologia , Tuberculose/veterinária , Zâmbia/epidemiologia
19.
Jpn J Vet Res ; 54(1): 15-23, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16786974

RESUMO

Anthrax is endemic in Western and North-western Provinces of Zambia. The disease occurs throughout the year and impacts negatively on the economy of the livestock industry and public health in Zambia. During 1989-1995, there were 1626 suspected cases of anthrax in cattle in Western province and of these 51 were confirmed. There were 220 cases of human anthrax cases in 1990 alone and 248 cases during 1991-1998 with 19.1% and 7.7% case fatality rates, respectively. Interplay of the ecology of affected areas and anthropogenic factors seem to trigger anthrax epidemics. Anthrax has drawn considerable attention in recent years due to its potential use as a biological weapon. In this paper, the history, current status and approaches towards the control of the disease in Zambia are discussed. Quarantine measures restrict trade of livestock and exchange of animals for draught power resulting in poor food security at household levels. Challenges of anthrax control are complex and comprise of socio-political, economical, environmental and cultural factors. Inadequate funding, lack of innovative disease control strategies and lack of cooperation from stakeholders are the major constraints to the control of the disease. It is hoped that the information provided here will stimulate continued awareness for the veterinary and medical authorities to maintain their surveillance and capabilities against the disease. This may lead to a culminating positive impact on livestock and human health in the southern African region.


Assuntos
Antraz/epidemiologia , Antraz/veterinária , Bacillus anthracis/crescimento & desenvolvimento , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Surtos de Doenças/veterinária , Zoonoses/epidemiologia , Zoonoses/microbiologia , Animais , Antraz/microbiologia , Bovinos , Ecologia , Humanos , Zâmbia/epidemiologia
20.
Front Microbiol ; 7: 1986, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28018317

RESUMO

Studies on the epidemiology of viral diseases in aquaculture have for a long time depended on isolation of viruses from infected aquatic organisms. The role of aquatic environments in the epidemiology of viral diseases in aquaculture has not been extensively expounded mainly because of the lack of appropriate tools for environmental studies on aquatic viruses. However, the upcoming of metagenomics analyses opens great avenues in which environmental samples can be used to study the epidemiology of viral diseases outside their host species. Hence, in this review I have shown that epidemiological factors that influence the composition of viruses in different aquatic environments include ecological factors, anthropogenic activities and stocking densities of cultured organisms based on environmental metagenomics studies carried out this far. Ballast water transportation and global trade of aquatic organisms are the most common virus dispersal process identified this far. In terms of disease control for outdoor aquaculture systems, baseline data on viruses found in different environments intended for aquaculture use can be obtained to enable the design of effective disease control strategies. And as such, high-risk areas having a high specter of pathogenic viruses can be identified as an early warning system. As for the control of viral diseases for indoor recirculation aquaculture systems (RAS), the most effective disinfection methods able to eliminate pathogenic viruses from water used in RAS can be identified. Overall, the synopsis I have put forth in this review shows that environmental samples can be used to study the epidemiology of viral diseases in aquaculture using viral metagenomics analysis as an overture for the design of rational disease control strategies.

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