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Ebola virus outbreaks in Africa: Past and present
2012
J.J. Muyembe-Tamfum | S. Mulangu | Justin Masumu | J.M. Kayembe | A. Kemp | Janusz T. Paweska
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 Côte d’Ivoire 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.
Show more [+] Less [-]Immunogeno: Protective mechanism for Rift Valley fever in the Democratic Republic of Congo
2012
Georges Tshilenge
Rift Valley fever (RVF) is an acute, fever causing viral disease that affects domestic animals and humans. In Democratic Republic of Congo (DRC), this pathology is not well documented. No epidemic of the RVF has not been reported but sera samples collected in six provinces surveyed from 2005 to 2006 revealed 14% of apparent prevalence and, high apparent prevalence (20%) of antibodies against RVF virus was reported in Katanga Province during the same survey; this serological evidence was associated with abortions cases in Cattle (Mulumba et al. 2009). Livestock immunisation is important for control of Rift Valley fever virus (RVFV) epidemics; however immunisation of susceptible domestic animals in endemic countries does not protect animals against the clinical disease but prevents the propagation of virus to human population through reduction of the amplification degree in host animals. The humoral immunity is sufficient for protection for animals as well as for humans. The infection caused by RVFV leads to neutralisation of the immunity of the animal (Barnard 1979). Various immunological studies have been made on the characterisation of immune response during RVFV epidemics but, until now several studies have been concentrated on the response of the innate immune particularly based on signal interferon system than the response of the adaptive immune and cell mediated humoral immune. The available information on the immune response related to RVFV does not seem to provide enough information on various mechanisms of the response immune system. The aim of the study is based on mechanism of immune response system including protective effect of immunisation against RVFV. In addition, epidemiological and molecular studies will be assessed. As a matter of fact, following studies will be conducted: • evaluation of the immunological protection against Rift Valley fever in vaccinated and non- vaccinated cattle using IgG and IgM ELISAs in Katanga Province • assessment of cellular response to Rift Valley fever disease in vaccinated and naturally infected cattle • molecular characterisation of RVFV strains circulating in vaccinated and non vaccinated cattle • assessment of protective effect related to vaccinal strains in cattle, using a longitudinal survey. The studies will be carried out Northern Katanga Province within two areas, one with historyof circulation of RVFV and other without history RVFV circulation. Whole blood, spleen, liver, lymph node will be collected as target tissues from cattle carcasses. In addition, goats and sheeps samples will be collected alongside from each area in order to clarify the disease situation. Serological tests based on the detection of Ig M and Ig G will be used. DIVA tests, LAMP, and IHC techniques will be used. Within previously vaccinated areas in the above mentioned areas and those that are not vaccinated, the collected samples will be analysed using RT-PCR/RT-LAMP. In vitro experimental studies systems will be carried out using animal PMBCs that will be infected with wild type of RVF virus as well as with vaccinal strains, such as clones 13 and MP12 to characterise various cell types such as CD4 T cells, CD8 T cells, B-cells, NK cells and, macrophages will be studied with regard to activation and apoptosis signals on various post – infection days, using flow cytometry. A pool of animals will be vaccinated with the Clone 13 and another with the MP12 to determine the traceability. The monitoring of the immune response will be done through the measurement of immunoglobulin G (Ig G) and immunoglobulin M (Ig M). RT-PCR, spectrophotometer or Facs methods will be used for the dosage of cells T CD4 + and Cell T CD8+.
Show more [+] Less [-]‘One Health’ infectious diseases surveillance in Tanzania: Are we all on board the same flight?
2012
Erasto V. Mbugi | Kim A. Kayunze | Bugwesa Z. Katale | Sharon Kendall | Liam Good | Gibson S. Kibik | Julius D. Keyyu | Peter Godfrey-Faussett | Paul van Helden | Mecky I. Matee
Infectious diseases account for nearly 40% of the burden of human mortality and morbidity in low-income countries, of which 7% is attributable to zoonoses and 13% to recently emerging diseases from animals. One of the strategic approaches for effective surveillance, monitoring and control of infectious diseases compromising health in both humans and animals could be through a combination of multiple disciplines. The approach can be achieved through a joint effort from stakeholders comprising health professionals (medical and veterinary), social, economic, agricultural, environmental and other interested parties. With resource scarcity in terms of number of staff, skills and facility in low-income countries, participatory multi- sectoral and multidisciplinary approaches in limiting the burden of zoonotic diseases could be worthwhile. We review challenging issues that may limit the ‘One Health’ approach for infectious diseases surveillance in Tanzania with a focus on Health Policy and how best the human and animal health systems could be complemented or linked to suit the community in need for disease control under the theme’s context.
Show more [+] Less [-]A survey of antimicrobial residues in table eggs in Khartoum State, Sudan, 2007–2008
2012
Mohamed M. Sirdar | Jackie Picard | Shahn Bisschop | Alexander R. Jambalang | Bruce Gummow
The risk to consumers of antimicrobial residues in table eggs produced in Khartoum State, Sudan, was studied. All producing layer farms (n = 175) in the state were sampled in April, June and August 2008. A total of 933 eggs from 335 layer houses were screened for antimicrobial residues by using the growth inhibition of Geobacillus stearothermophilus var. calidolactis in-house test. A high proportion of layer farms (72% in April, 61% in June and 66% in August) and layer houses (63% April, 59% in June and 61% in August) were found to have antimicrobial residues, with no significant difference in prevalence (p = 0.57) between study periods. The study showed that the consumer was at constant risk of exposure to antimicrobial residues in table eggs. The paper discusses reasons for the high prevalence of antimicrobial residues in Sudanese eggs and its implications, and makes recommendations to address this important public health problem.
Show more [+] Less [-]One Health: Towards safeguarding the health, food security and economic welfare of communities
2012
Nabarro, David(the United Nations Food Security and Nutrition)
Zoonotic diseases and human health: The human influenza example
2012
Schoub, Barry D(National Institute for Communicable Diseases)
Over the past few decades a large number of new and emerging infectious diseases have been recognised in humans, partly because of improved diagnostic technologies and increased awareness and also, partly because of dynamic ecological changes between human hosts and their exposure to animals and the environment (Coker et al. 2011). Some 177 new pathogenic organisms have been recognised to be 'emerging', that is, have newly arisen or been newly introduced into human populations; almost three quarters of these, 130 (73%), have come from zoonotic origins (Cascio et al. 2011; Cutler, Fooks & Van Der Poel 2010; Taylor, Latham & Woolhouse 2001; Woolhouse & Gowtage-Sequeria 2005). One of the most prevalent and important human infectious disease is influenza, a disease responsible globally for a quarter million deaths annually. In the USA alone the toll from influenza is estimated at 36 000 deaths and 226 000 hospitalisations, and it ranks as the most important cause of vaccine preventable mortality in that country (CDC 2010). The epidemiological behaviour of human influenza clearly defines it as an emerging infectious disease and the recent understanding of its zoonotic origins has contributed much to the understanding of its behaviour in humans (Fauci 2006).
Show more [+] Less [-]Bartonella spp. in human and animal populations in Gauteng, South Africa, from 2007 to 2009
2012
Trataris, Anastasia N(National Health Laboratory Service) | Rossouw, Jennifer(National Health Laboratory Service) | Arntzen, Lorraine(National Health Laboratory Service) | Karstaedt, Allan(National Health Laboratory Service) | Frean, John(National Health Laboratory Service)
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 °C 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.
Show more [+] Less [-]Towards One Health disease surveillance: The Southern African Centre for Infectious Disease Surveillance approach
2012
Karimuribo, Esron D.(Southern African Centre for Infectious Disease Surveillance) | Sayalel, Kuya(Ngorongoro Conservation Area Authority) | Beda, Eric(Southern African Centre for Infectious Disease Surveillance) | Short, Nick(Royal Veterinary College) | Wambura, Philemon(Southern African Centre for Infectious Disease Surveillance) | Mboera, Leonard G.(National Institute for Medical Research) | Kusiluka, Lughano J.M.(The Open University of Tanzania) | Rweyemamu, Mark M.(Southern African Centre for Infectious Disease Surveillance)
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.
Show more [+] Less [-]Epidemiological investigation into the introduction and factors for spread of Peste des Petits Ruminants, southern Tanzania
2012
Muse, Epaphras A.(Sokoine University of Agriculture Department of Veterinary Microbiology and Parasitology) | Karimuribo, Esron D(Sokoine University of Agriculture Department of Veterinary Medicine and Public Health) | Gitao, George C(University of Nairobi Department of Veterinary pathology, Microbiology and Pathology) | Misinzo, Gerald(Sokoine University of Agriculture Department of Veterinary Microbiology and Parasitology) | Mellau, Lesakit S.B.(Sokoine University of Agriculture Department of Veterinary Medicine and Public Health) | Msoffe, Peter L.M.(Sokoine University of Agriculture Department of Veterinary Medicine and Public Health) | Swai, Emmanuel S.(Veterinary Investigation Centre Arusha) | Albano, Mbyuzi O.(Veterinary Investigation Centre Arusha)
A study was carried out to confirm and identify sources and elucidate factors associated with the introduction of Peste des Petits Ruminants (PPR) in southern Tanzania. This study was conducted in Tandahimba and Newala districts of Mtwara region following suspected outbreak of PPR in the area. Qualitative data were collected using semi-structured questionnaires and in-depth interviews of key informants who included goat and sheep owners with suspected cases of PPR and animal health service providers as well as local administrative authority. Additionally, 216 serum samples and 28 swabs were collected for serological and virological laboratory disease confirmation. The results show that PPR was first introduced in Likuna village of Newala district in February 2009 through newly purchased goats from the Pugu livestock market located about 700 km in the outskirts of Dar es Salaam city. Factors which contributed to spread of PPR included communal grazing and the cheap prices of sick animals bought by livestock keepers for slaughtering in other villages. Laboratory findings confirmed presence of PPR in the area by RT-PCR and serological analysis revealed that seroprevalence was 31%. These findings have confirmed, for the first time, introduction of PPR in southern Tanzania. The presence of PPR poses high risk of southward spread of the disease to other southern African countries in the SADC region thus calling for concerted and collaborative efforts in prevention and control of the disease to avoid losses. Further elaborate studies on the spread, prevalence and risk factors associated with the disease should urgently be investigated.
Show more [+] Less [-]A foresight vision for infectious diseases in Africa
2012
Brownlie, Joe(Royal Veterinary College)