خيارات البحث
النتائج 201 - 210 من 674
Genomic sequence of infectious bursal disease virus from Zambia suggests evidence for genome re-assortment in nature النص الكامل
2012
Christopher J. Kasanga | T. Yamaguchi | H.M. Munang’andu | P.N. Wambura | K. Ohya | H. Fukushi
Infectious bursal disease virus (IBDV) is a bi-segmented RNA virus, which belongs to the genus Avibirnavirus of the family Birnaviridae. Two serotypes, 1 and 2, exist in IBDV. The serotype 1 IBDVs are the causative agents of infectious bursal disease (IBD) in chickens worldwide and lead to immunosuppression in young birds. Genome re-assortment has been speculated to occur and contribute to the emergence of new IBDV strains. However, evidence was lacking until recently when two re-assortant viruses were detected in China. In this study, we determined the complete nucleotide sequence of an IBDV, designated KZC-104, from a confirmed natural IBD outbreak in Lusaka, Zambia in 2004. The genome consisted of 3074 and 2651 nucleotides in the coding regions of segments A and B, respectively. Alignment of both nucleotide and deduced amino acid sequences, and phylogenetic analysis revealed that the genome segment A of KZC-104 was derived from a very virulent strain, whereas its segment B was derived from a classical attenuated strain. On BLAST search, the full-length segments A and B sequences showed 98% closest nucleotide homology to the very virulent strain D6948 and 99.8% closest nucleotide homology to the classical attenuated strain D78, respectively. This is a unique IBDV reassortant strain, which has emerged in nature involving segment B of a live attenuated vaccine. This observation provides direct evidence for the involvement of vaccine strains in the emergence of reassortant IBDV in the field. Taken together, these findings suggest an additional risk of using live IBDV vaccines, which may act as genetic donors for genome re-assortment. Further studies are required to investigate the epidemiology and biological characteristics of reassortant strains so that the appropriate and safe IBDV vaccines can be recommended.
اظهر المزيد [+] اقل [-]Unexpectedly low seroprevalence of toxoplasmosis in South Africa النص الكامل
2012
K. Kistiah | John Frean | J. Winiecka-Krusnell | A. Barragan
Toxoplasmosis is an infection of warm-blooded vertebrates caused by the obligate intracellular protozoan parasite, Toxoplasma gondii. It is one of the most common parasitic diseases of humans, infecting approximately one-third of the world’s population. In persons with advanced HIV, toxoplasmosis represents a major opportunistic infection of the central nervous system. Approximately two-thirds of all people living with HIV live in sub-Saharan Africa. In areas such as this, toxoplasmosis could theoretically pose a huge threat. There is little known about T. gondii prevalence in humans in Africa. Geographically, prevalences vary widely on this continent, as observed in other parts of the world. There is limited historical information about the disease in South Africa. More knowledge is needed at a regional level about the risk of toxoplasmosis, diagnostic issues, and measures to reduce the risk to susceptible persons. The seroprevalence of T. gondii in selected populations, namely HIV-positive and HIV-negative individuals, and a more general sample biased towards pregnant women, was therefore investigated and found to be 9.8% (37/376), 12.8% (48/376) and 6.4% (32/497) respectively. Compared with historical data from South Africa, the prevalence has decreased substantially; however, the incidence of clinical disease is unknown, despite the very high burden of HIV and AIDS cases (5.9 million and 0.7 million, respectively in 2009). This study provided information relating to the diagnosis and current seroprevalence of T. gondii in South Africa. Many questions still remain to be answered however, to fully understand the impact of this parasite on the country’s population.
اظهر المزيد [+] اقل [-]First International One Health congress النص الكامل
2012
Martyn H. Jeggo
More than 650 people from around 60 countries attended the 1st International One Health Conference, held in Melbourne from 14 to 16 February 2011. Scientists, clinicians, government and community members from a range of disciplines came together to discuss the benefits of working together to promote a One Health approach to human, animal and environmental health. One Health embraces systems thinking and recognising the interdependence of people, animals and environment. The conference was hosted by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and was supported by international agencies, the Australian and Canadian governments, and industry. The Organising Committee recognised from the outset, the need to provide a forum not just for scientific presentation, but for open discussion and dialogue around the policy and political issues, as well as the science that drives the One Health agenda. The Committee was also cognizant of the need to embrace a definition of One Health that includes food security and food safety and included the social and economic pressures that shapes this area. The meeting was therefore organised under four themes with plenary sessions followed by breakout parallel sessions for each of these. The themes covered Disease Emergence, Environmental Drivers, Trade, Food Security and Food Safety, and Science Policy and Political Action. The plenary session commenced with one or two keynote presentations by world leaders on the topic being covered, followed by panel discussions involving six to eight experts and involving all participants at the congress. Each of the panel members spoke briefly on the topic covered by the keynote speaker and were asked to be as provocative as possible. The discussions that followed allowed debate and discussion on the keynote presentations and the panel members comments. This was followed by six to eight parallel breakout sessions involving in depth papers on the session’s topic. Throughout the conference at various times, sponsored sessions dealt with particular areas of science or policy providing a further framework not only to learn current science but for debate and discussion. A full copy of all abstracts is available on the web at http://www.springerlink.com. In concluding the Congress recognised the interdependence of, and seeks to improve human, animal and environmental health; recognised that communication, collaboration and trust between human and animal health practitioners is at the heart of the One Health concept; agreed that a broad vision that includes other disciplines such as economics and social behaviour is essential to success. The Congress stressed the need to promote the ‘do-able’ such as improving surveillance and response for emerging infectious diseases whilst developing the broader approach. It identified a need to emphasise community participation and development of community capacity, and especially, an open transparent dialogue with both a ‘ground up’ and ‘top down’ approach that would lead to an improved understanding of our ecosystems, including molecular ecobiology, are an essential part of One Health.
اظهر المزيد [+] اقل [-]Filoviral haemorrhagic fevers: A threat to Zambia? النص الكامل
2012
Katendi Changula | A.S. Mweene
Filoviral haemorrhagic fevers (FVHF) are caused by agents belonging to Filoviridae family, Ebola and Marburg viruses. They are amongst the most lethal pathogens known to infect humans. Incidence of FVHF outbreaks are increasing, with affected number of patients on the rise. Whilst there has been no report yet of FVHF in Zambia, its proximity to Angola and Democratic Republic of Congo, which have recorded major outbreaks, as well as the open borders, increased trade and annual migration of bats between these countries, puts Zambia at present and increased risk. Previous studies have indicated bats as potential reservoir hosts for filoviruses. An increasing population with an increasing demand for resources has forced incursion into previously uninhabited land, potentially bringing them into contact with unknown pathogens, reservoir hosts and/or amplifying hosts. The recent discovery of a novel arenavirus, Lujo, highlights the potential that every region, including Zambia, has for being the epicentre or primary focus for emerging and re-emerging infections. It is therefore imperative that surveillance for potential emerging infections, such as viral haemorrhagic fevers be instituted. In order to accomplish this surveillance, rapid detection, identification and monitoring of agents in patients and potential reservoirs is needed. International co-operation is the strategy of choice for the surveillance and fight against emerging infections. Due to the extensive area in which filoviral infections can occur, a regional approach to surveillance activities is required, with regional referral centres. There is a need to adopt shared policies for the prevention and control of infectious diseases. There is also need for optimisation of currently available tests and development of new diagnostic tests, in order to have robust, highly sensitive and specific diagnostic tests that can be used even where there are inadequate laboratories and diagnostic services.
اظهر المزيد [+] اقل [-]Resource mapping and emergency preparedness to infectious diseases in human and animal populations in Kibaha and Ngorongoro districts, Tanzania النص الكامل
2012
E.D. Karimuribo | B. Jones | M.I. Matee | D.M. Kambarage | S. Mounier-Jack | M.M. Rweyemamu
A rapid situation analysis was conducted in Kibaha and Ngorongoro districts in Tanzania to map resources as well as analysing emergency preparedness to infectious diseases in animal (domestic and wild) and human populations. Kibaha was chosen as a district close to a commercial city (Dar es Salaam) while Ngorongoro represented a remote, border district with high interactions between humans, domestic and wild animals. In this study, data on resources and personnel as well as emergency preparedness were collected from all wards (n = 22), human health facilities (n = 40) and livestock facilities in the two districts using interview checklists and questionnaires. Descriptive statistics for resources were calculated and mapped by district. Kibaha district had a higher human population density, more health workers, better equipped health facilities and better communication and transport systems. On the other hand, Ngorongoro had a higher population of livestock and more animal health facilities but a poorer ratio of animal health workers to livestock. The average ratio of health personnel to population in catchment areas of the health facilities was 1:147 (range of 1:17−1:1200). The ratio of personnel to human population was significantly higher in Kibaha (1:95) than in Ngorongoro (1:203) district (p = 0 < 0.001). Considering the limited resources available to both human and animal health sectors and their different strengths and weaknesses there are opportunities for greater collaboration and resource-sharing between human and animal health for improved surveillance and emergency-preparedness.
اظهر المزيد [+] اقل [-]<i>Bartonella</i> spp. in human and animal populations in Gauteng, South Africa, from 2007 to 2009 النص الكامل
2012
Anastasia N. Trataris | Jennifer Rossouw | Lorraine Arntzen | Allan Karstaedt | John Frean
Bartonellae are highly adaptive organisms that have the ability to evade the host immune system and cause persistent bacteraemia by occupying the host’s erythrocytes. Bartonella spp. is under-studied and health care professionals often misdiagnose Bartonella-related infections. The aim of this study was to investigate the carriage of Bartonella spp. circulating in human and animal populations in Gauteng using culturing and polymerase chain reaction (PCR) detection. A total of 424 human, 98 cat, 179 dog, and 124 wild rodent blood samples were plated onto specialised media and incubated for 7–21 days at 37 ºC in CO2. Culture isolates morphologically similar to Bartonella control strains were confirmed by PCR and sequenced to determine species. Deoxyribonucleic acid (DNA) was extracted from all blood samples and tested by nested PCR. Bartonella could only be cultured from the cat and rodent specimens. Cat isolates were > 99% similar to Bartonella henselae URBHLIE 9, previously isolated from an endocarditis patient, and rat isolates were > 98% similar to either RN24BJ (candidus ‘Bartonella thailandensis’) or RN28BJ, previously isolated from rodents in China. The PCR prevalences were 22.5% in HIV-positive patients, 9.5% in clinically healthy volunteers, 23.5% in cats, 9% in dogs and 25% in rodents. Findings of this study have important implications for HIV-positive patients.
اظهر المزيد [+] اقل [-]Acknowledgement to reviewers النص الكامل
2012
Editorial Office
Effect of packing on changes in erythrocyte osmotic fragility and malondialdehyde concentration in donkeys administered with ascorbic acid النص الكامل
2012
Folashade Olaifa | Joseph O. Ayo | Suleiman F. Ambali | Peter I. Rekwot
Experiments were performed with the aim of investigating the effect of packing on erythrocyte osmotic fragility (EOF) and malondialdehyde (MDA) concentration in donkeys, and the effect of ascorbic acid (AA). Twelve apparently healthy donkeys raised under the traditional extensive system served as experimental subjects. Six donkeys administered orally with AA (200 mg/kg) and subjected to packing were used as experimental animals, whilst six others not administered with AA served as controls. Blood samples were collected pre- and post-packing from all the donkeys for the determination of MDA and EOF. At 0.3% Sodium Chloride (NaCl) concentration, the percentage haemolysis was 93.69% ± 2.21% in the control donkeys and the value was significantly (<em>P</em> < 0.05) higher than the value of 71.31% ± 8.33%, recorded in the experimental donkeys. The post-packing MDA concentration obtained in the control donkeys was 39.62 µmol ± 4.16 µmol, and was not significantly different (<em>P</em> > 0.05) from the value of 35.97 µmol ± 2.88 µmol recorded in the experimental donkeys. In conclusion, the increase in haemolysis obtained in the donkeys suggested that packing induced oxidative stress, which was ameliorated by AA administration.
اظهر المزيد [+] اقل [-]The epidemiology and socio-economic impact of Rift Valley fever epidemics in Tanzania: A review النص الكامل
2012
Calvin Sindato | Esron Karimuribo | E.G. Mboera
A review was conducted to provide comprehensive update on Rift Valley fever (RVF) in Tanzania, with particular attention devoted to trend of occurrence, epidemiological factors, socio-economic impact and measures which were applied to its control. Information presented in this paper was obtained through extensive literature review. Rift Valley fever was documented for the first time in Tanzania in 1977. This was followed by epidemics in 1997 and 2007. Contrary to the latest epidemic in 2007 sporadic cases of RVF during the previous epidemics were confined to mainly livestock and mostly affecting northern parts of Tanzania. The latest disease epidemic expanded to cover wider areas (mostly northern and central zones) of the country involving both human and domestic ruminants. During the latest disease outbreak 52.4% (n = 21) of regions in Tanzania mainland were affected and majority (72.7, n = 11) of the regions had concurrent infections in human and animals. Phylogenetic comparison of nucleotide and amimo acid sequences revealed different virus strains between Kenya and Tanzania. Epidemiological factors that were considered responsible for the previous RVF epidemics in Tanzania included farming systems, climatic factors, vector activities and presence of large population of ruminant species, animal movements and food consumption habits. Majority of the RVF positive cases in the latest epidemic were livestock under pastoral and agro-pastoral farming systems. The disease caused serious effects on rural people’s food security and household nutrition and on direct and indirect losses to livestock producers in the country. Psycho-social distress that communities went through was enormous, which involved the thinking about the loss of their family members and/or relatives, their livestock and crop production. Socially, the status of most livestock producers was eroded in their communities. Cessation of lucrative trade in ruminants resulted in serious economic losses to the populations who were totally dependent upon this income. Livestock internal market flows drastically dropped by 37% during latest epidemic. Rift Valley fever epidemics had dramatic impact of RVF outbreak on the international animal trade in which there was a 54% decline in exports equivalent to loss of $352 750.00. The estimate of loss as a result of deaths for cattle was $4 243 250.00 whereas that of goats and sheep was $2 202 467.00. Steps taken to combat epidemics included restriction of animal movements, ban of the slaughter of cattle and vaccination of livestock and health education. From past epidemics we have learnt that each subsequent outbreak had expanded to cover wider areas of the country. The disease had dramatic socio-economic impacts both at community and nation at large. The main challenges related to the control of RVF outbreaks included lack of preparedness plan for RVF, poor coordination and information transmission, limited facilities and manpower for RVF outbreak intervention. Control of the 2007 RVF epidemic was largely the result of animal and human health agencies working in an integrated manner.
اظهر المزيد [+] اقل [-]One Health: Towards safeguarding the health, food security and economic welfare of communities النص الكامل
2012
David Nabarro