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Towards One Health disease surveillance: The Southern African Centre for Infectious Disease Surveillance approach
2012
Esron D. Karimuribo | Kuya Sayalel | Eric Beda | Nick Short | Philemon Wambura | Leonard G. Mboera | Lughano J.M. Kusiluka | Mark M. Rweyemamu
Africa has the highest burden of infectious diseases in the world and yet the least capacity for its risk management. It has therefore become increasingly important to search for ‘fit-for- purpose’ approaches to infectious disease surveillance and thereby targeted disease control. The fact that the majority of human infectious diseases are originally of animal origin means we have to consider One Health (OH) approaches which require inter-sectoral collaboration for custom-made infectious disease surveillance in the endemic settings of Africa. A baseline survey was conducted to assess the current status and performance of human and animal health surveillance systems and subsequently a strategy towards OH surveillance system was developed. The strategy focused on assessing the combination of participatory epidemiological approaches and the deployment of mobile technologies to enhance the effectiveness of disease alerts and surveillance at the point of occurrence, which often lies in remote areas. We selected three study sites, namely the Ngorongoro, Kagera River basin and Zambezi River basin ecosystems. We have piloted and introduced the next-generation Android mobile phones running the EpiCollect application developed by Imperial College to aid geo-spatial and clinical data capture and transmission of this data from the field to the remote Information Technology (IT) servers at the research hubs for storage, analysis, feedback and reporting. We expect that the combination of participatory epidemiology and technology will significantly improve OH disease surveillance in southern Africa.
Afficher plus [+] Moins [-]Prevalence, predilection sites and pathological findings of <i>Taenia multiceps</i> coenuri in slaughtered goats from south-east Iran
2012
Reza Kheirandish | Masoud Sami | Shahrzad Azizi | Mohammad Mirzaei
Coenurosis is a zoonotic disease in a variety of ruminants caused by the metacestode of<em> Taenia multiceps</em>. The coenuri in the brain and spinal cord of sheep and goats have been identified as Coenurus cerebralis whilst those reported in other tissues have been named Coenurus gaigeri. This study was conducted during the spring and summer of 2011. Out of 25 739 goats inspected in slaughterhouses, 23 carcasses (0.09%) revealed one or multiple visible swellings on the different muscles and visceral organs. The coenuri, of variable sizes, were found mainly in the muscles of the thigh, shoulder and neck, and were less common in the abdominal muscles and subcutaneous tissues. Coenuri were also found in the diaphragm, tongue, intercostal muscles, lung, parotid area and tunica adventitia of the aorta in a goat with severe infection. The brains of slaughtered goats that had coenuri in their skeletal muscles were examined and coenuri were found in two specimens (8.69%). The coenuri were located in the occipital lobe, the anterior part of the right cerebrum and the parietal lobe of the left cerebrum. Histopathologically, coenuri in the brain caused pressure atrophy and liquefactive necrosis in the surrounding tissues, hyperaemia, perivascular cuffing, neuronal degeneration, neuronophagia, satellitosis, diffuse microgliosis and astrocytosis. Coenuri in the skeletal muscles caused degenerative and necrotic changes, hyalinisation and myositis. In the lung, tissues around the coenurus revealed atelectasis and focal interstitial fibrosis. In the present study, concurrent occurrence of coenuri in the central nervous system and skeletal muscles supports the hypothesis that C. cerebralis and C. gaigeri are different names for the metacestodes of the same species of tapeworm.
Afficher plus [+] Moins [-]Ectoparasites of sheep in three agro-ecological zones in central Oromia, Ethiopia
2012
Bersissa Kumsa | Kebede Beyecha | Mesula Geloye
A cross-sectional study was conducted to determine the prevalence and risk factors for ectoparasites infestation in sheep in three agro-ecological zones in central Oromia, Ethiopia, from October 2009 to April 2010. The study revealed that 637 (48.1%) of the 1325 sheep examined were infested with one or more ectoparasites. The ectoparasites identified were <em>Bovicola ovis</em> (27.2%), <em>Melophagus ovinus</em> (16.4%), <em>Ctenocephalides</em> sp. (2.3%), <em>Linognathus africanus</em> (1.2%), <em>Linognathus ovillus </em> (0.3%),<em> Sarcoptes</em> sp. (1.2%), <em>Amblyomma variegatum</em> (4.4%), <em>Rhipicephalus evertsi evertsi</em> (1.9%), <em>Rhipicephalus pravus</em> (1.9%), <em>Rhipicephalus</em> (<em>Boophilus</em>) <em>decoloratus</em> (1.1%), <em>Rhipicephalus sanguineus</em> (0.9%), <em>Rhipicephalus praetextatus</em> (1.1%) and <em>Hyalomma truncatum</em> (1.6%). Statistically significant difference was observed in prevalence of <em>B. ovis</em> amongst study agroecological zones: highland 36.6%, midland 20.9% and lowland 14.0%. Significantly higher prevalence was recorded in highland agroecological zone. A significantly (OR = 0.041, <em>p</em> < 0.001) higher prevalence of <em>M. ovinus</em> in the highland (31.7%) than in both the lowland (0%) and midland (1.9%) was observed. The risk of tick infestation in the lowland and midland was 9.883 times and 13.988 times higher than the risk in the highland, respectively. A significantly higher prevalence of <em>Ctenocephalides</em> species was encountered in both the lowland (OR = 4.738, <em>p</em> = 0.011) and midland (OR = 8.078, <em>p</em> = 0.000) than in the highland agro-ecological zone. However, a significant difference (<em>p</em> = 0.191) amongst agro-ecological zones was not found for the prevalence of <em>Linognathus</em> and <em>Sarcoptes </em>species. Statistically significant variation (<em>p</em> > 0.05) was never recorded in the prevalence of all the identified species of ectoparasites between male and female sheep hosts. However, a significantly (<em>p</em> = 0.006) higher prevalence of<em> B. ovis</em> was recorded between young and adult sheep. The risk of <em>B. ovis</em> infestation was 1.45 times higher in young than the adult sheep. Furthermore, a significantly (<em>p</em> < 0.001) higher prevalence of <em>M. ovinus</em>, <em>B. ovis</em> and <em>Sarcoptes</em> sp. was found between sheep with poor and a good body condition. The ever increasing threat of ectoparasites on overall sheep productivity and tanning industry in Ethiopia warrants urgent control intervention. Further studies on the role of ectoparasites in transmission of diseases to sheep, zoonotic importance, comparative prevalence and load, and the importance of sheep as alternative hosts in different agroecological zones, breeds and management systems in Ethiopia are recommended so as to design applicable control programme in the country.
Afficher plus [+] Moins [-]Foot-and-mouth disease virus serotypes detected in Tanzania from 2003 to 2010: Conjectured status and future prospects
2012
Christopher J. Kasanga | Raphael Sallu | Fredrick Kivaria | Mathias Mkama | Joseph Masambu | Mmeta Yongolo | Sachindra Das | Chanasa Mpelumbe-Ngeleja | Philemon N. Wambura | Donald P. King | Mark M. Rweyemamu
This study was conducted to investigate the presence of foot-and-mouth disease virus (FMDV) in different geographic locations of Tanzania. Epithelial tissues and fluids (n = 364) were collected from cattle exhibiting oral and foot vesicular lesions suggestive of FMD and submitted for routine FMD diagnosis. The analysis of these samples collected during the period of 2002 and 2010 was performed by serotype-specific antigen capture ELISA to determine the presence of FMDV. The results of this study indicated that 167 out of 364 (46.1%) of the samples contained FMDV antigen. Of the 167 positive samples, 37 (28.4%) were type O, 7 (4.1%) type A, 45 (21.9%) SAT 1 and 79 (45.6%) SAT 2. Two FMDV serotypes (O and SAT 2) were widely distributed throughout Tanzania whilst SAT 1 and A types were only found in the Eastern zone. Our findings suggest that serotypes A, O, SAT 1 and SAT 2 prevail in Tanzania and are associated with the recent FMD outbreaks. The lack of comprehensive animal movement records and inconsistent vaccination programmes make it difficult to determine the exact source of FMD outbreaks or to trace the transmission of the disease over time. Therefore, further collection and analysis of samples from domestic and wild animals are being undertaken to investigate the genetic and antigenic characteristics of the circulating strains, so that a rational method to control FMD in Tanzania and the neighbouring countries can be recommended.
Afficher plus [+] Moins [-]Towards one Africa, one health: The Southern African Centre for Infectious Disease Surveillance One Health focus on infectious diseases
2012
Rweyemamu, Mark M.(Sokoine University of Agriculture Southern African Centre for infectious diseases surveillance) | Paweska, Janusz(Sokoine University of Agriculture Southern African Centre for infectious diseases surveillance) | Kambarage, Dominic(Sokoine University of Agriculture Southern African Centre for infectious diseases surveillance) | Namuba, Filomena(Sokoine University of Agriculture Southern African Centre for infectious diseases surveillance)
Ebola virus outbreaks in Africa: Past and present
2012
Muyembe-Tamfum, J.J.(Institut national de Recherche Biomédicale) | Mulangu, S.(Southern African Centre for Infectious Disease Surveillance) | Masumu, Justin(Institut national de Recherche Biomédicale) | Kayembe, J.M.(Université de Kinshasa) | Kemp, A.(National Institute for Communicable Diseases of the National Health Laboratory Service) | Paweska, Janusz T(National Institute for Communicable Diseases of the National Health Laboratory Service)
Ebola haemorrhagic fever (EHF) is a zoonosis affecting both human and non-human primates (NHP). Outbreaks in Africa occur mainly in the Congo and Nile basins. The first outbreaks of EHF occurred nearly simultaneously in 1976 in the Democratic Republic of the Congo (DRC, former Zaire) and Sudan with very high case fatality rates of 88% and 53%, respectively. The two outbreaks were caused by two distinct species of Ebola virus named Zaire ebolavirus (ZEBOV) and Sudan ebolavirus (SEBOV). The source of transmission remains unknown. After a long period of silence (1980-1993), EHF outbreaks in Africa caused by the two species erupted with increased frequency and new species were discovered, namely Cote d'lvoire ebolavirus (CIEBOV) in 1994 in the Ivory Coast and Bundibugyo ebolavirus (BEBOV) in 2007 in Uganda. The re-emergence of EHF outbreaks in Gabon and Republic of the Congo were concomitant with an increase in mortality amongst gorillas and chimpanzees infected with ZEBOV. The human outbreaks were related to multiple, unrelated index cases who had contact with dead gorillas or chimpanzees. However, in areas where NHP were rare or absent, as in Kikwit (DRC) in 1995, Mweka (DRC) in 2007, Gulu (Uganda) in 2000 and Yambio (Sudan) in 2004, the hunting and eating of fruit bats may have resulted in the primary transmission of Ebola virus to humans. Human-to-human transmission is associated with direct contact with body fluids or tissues from an infected subject or contaminated objects. Despite several, often heroic field studies, the epidemiology and ecology of Ebola virus, including identification of its natural reservoir hosts, remains a formidable challenge for public health and scientific communities.
Afficher plus [+] Moins [-]The African buffalo: A villain for inter-species spread of infectious diseases in southern Africa
2012
Michel, Anita L.(University of Pretoria Department of Veterinary Tropical Diseases) | Bengis, Roy G(Directorate Veterinary Services)
The African buffalo (Syncerus caffer) is a large wild bovid which until recently ranged across all but the driest parts of sub-Saharan Africa, and their local range being limited to about 20 km from surface water. They are of high ecological value due to their important role as bulk feeders in the grazing hierarchy. They also have high economic value, because they are one of the sought after 'Big Five' in the eco-tourism industry. In Africa, buffaloes have been recognised for some time as an important role player in the maintenance and transmission of a variety of economically important livestock diseases at the wildlife and/or livestock interface. These include African strains of foot-and-mouth disease (FMD), Corridor disease (theileriosis), bovine tuberculosis and bovine brucellosis. For a number of other diseases of veterinary importance, African buffaloes may also serve as amplifier or incidental host, whereby infection with the causative pathogens may cause severe clinical signs such as death or abortion as in the case of anthrax and Rift Valley fever, or remain mild or subclinical for example heartwater. The long term health implications of most of those infections on the buffalo at a population level is usually limited, and they do not pose a threat on the population's survival. Because of their ability to harbour and transmit important diseases to livestock, their sustainable future in ecotourism, trade and transfrontier conservation projects become complex and costly and reliable diagnostic tools are required to monitor these infections in buffalo populations.
Afficher plus [+] Moins [-]Electronic Integrated Disease Surveillance System and Pathogen Asset Control System
2012
Wahl, Tom G.(MosAlarko Plaza One) | Burdakov, Aleksey V.(MosAlarko Plaza One) | Oukharov, Andrey O.(MosAlarko Plaza One) | Zhilokov, Azamat K.(MosAlarko Plaza One)
Electronic Integrated Disease Surveillance System (EIDSS) has been used to strengthen and support monitoring and prevention of dangerous diseases within One Health concept by integrating veterinary and human surveillance, passive and active approaches, case-based records including disease-specific clinical data based on standardised case definitions and aggregated data, laboratory data including sample tracking linked to each case and event with test results and epidemiological investigations. Information was collected and shared in secure way by different means: through the distributed nodes which are continuously synchronised amongst each other, through the web service, through the handheld devices. Electronic Integrated Disease Surveillance System provided near real time information flow that has been then disseminated to the appropriate organisations in a timely manner. It has been used for comprehensive analysis and visualisation capabilities including real time mapping of case events as these unfold enhancing decision making. Electronic Integrated Disease Surveillance System facilitated countries to comply with the IHR 2005 requirements through a data transfer module reporting diseases electronically to the World Health Organisation (WHO) data center as well as establish authorised data exchange with other electronic system using Open Architecture approach. Pathogen Asset Control System (PACS) has been used for accounting, management and control of biological agent stocks. Information on samples and strains of any kind throughout their entire lifecycle has been tracked in a comprehensive and flexible solution PACS. Both systems have been used in a combination and individually. Electronic Integrated Disease Surveillance System and PACS are currently deployed in the Republics of Kazakhstan, Georgia and Azerbaijan as a part of the Cooperative Biological Engagement Program (CBEP) sponsored by the US Defense Threat Reduction Agency (DTRA).
Afficher plus [+] Moins [-]New technologies to diagnose and monitor infectious diseases of livestock: Challenges for sub-Saharan Africa
2012
King, Donald P.(Institute for Animal Health) | Madi, Miki(Institute for Animal Health) | Mioulet, Valerie(Institute for Animal Health) | Wadsworth, Jemma(Institute for Animal Health) | Wright, Caroline F.(Institute for Animal Health) | Valdazo-González, Begoña(Institute for Animal Health) | Ferris, Nigel P.(Institute for Animal Health) | Knowles, Nick J.(Institute for Animal Health) | Hammond, Jef(Institute for Animal Health)
Using foot-and-mouth disease (FMD) as an example, this review describes new tools that can be used to detect and characterise livestock diseases. In recent years, molecular tests that can detect and characterise pathogens in a diverse range of sample types have revolutionised laboratory diagnostics. In addition to use in centralised laboratories, there are opportunities to locate diagnostic technologies close to the animals with suspected clinical signs. Work in this area has developed simple-to-use lateral-flow devices for the detection of FMD virus (FMDV), as well as new hardware platforms to allow molecular testing to be deployed into the field for use by non-specialists. Once FMDV has been detected, nucleotide sequencing is used to compare field strains with reference viruses. Transboundary movements of FMDV are routinely monitored using VP1 sequence data, while higher resolution transmission trees (at the farm-to-farm level) can be reconstructed using full-genome sequencing approaches. New technologies such as next-generation sequencing technologies are now being applied to dissect the viral sequence populations that exist within single samples. The driving force for the use of these technologies has largely been influenced by the priorities of developed countries with FMD-free (without vaccination) status. However, it is important to recognise that these approaches also show considerable promise for use in countries where FMD is endemic, although further modifications (such as sample archiving and strain and serotype characterisation) may be required to tailor these tests for use in these regions. Access to these new diagnostic and sequencing technologies in sub-Saharan Africa have the potential to provide novel insights into FMD epidemiology and will impact upon improved strategies for disease control. Effective control of infectious diseases is reliant upon accurate diagnosis of clinical cases using laboratory tests, together with an understanding of factors that impact upon the epidemiology of the infectious agent. A wide range of new diagnostic tools and nucleotide sequencing methods are used by international reference laboratories to detect and characterise the agents causing outbreaks of infectious diseases. In the past, high costs (initial capital expenses, as well as day-to-day maintenance and running costs) and complexity of the protocols used to perform some of these tests have limited the use of these methods in smaller laboratories. However, simpler and more cost-effective formats are now being developed that offer the prospect that these technologies will be even more widely deployed into laboratories particularly those in developing regions of the world such as sub-Saharan Africa.
Afficher plus [+] Moins [-]One Health - 'joining the dots'
2012
Dockrell, Hazel M(London School of Hygiene & Tropical Medicine Department of Immunology and Infection)