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Phytochemical isolation of compounds from <i>Sceletium tortuosum</i> and activity testing against <i>Plasmodium falciparum</i>
2012
Itumeleng I. Setshedi | Gerda Fouche | John Dewar | Vinesh Maharaj | Martin S. Myer
Malaria is a major health care problem in tropical regions due to the increasing resistance of Plasmodium falciparum against widely available antimalarial drugs. Traditional societies relied on medicinal plants to treat parasitic infections. As a result, drugs like quinine and artemisinin were isolated from herbs and barks (Varughese et al. 2010). Sceletium tortuosum has been used as medicine for social and spiritual purposes by San hunter gatherers and Khoi pastoralists. Sceletium tortuosum is rich in alkaloids, one of the important classes of natural product producing treatment for parasitic infections (Kayser et al. 2002). Laboratory preparation of extracts of fresh S. tortuosum plant material was conducted mimicking traditional methods of preparation using organic solvents. Mesembrine was isolated from a methanol extract using conventional column chromatography. Sixteen extracts and mesembrine were evaluated for antiplasmodium activity using a plasmodium lactate dehydrogenase culture sensitivity assay with chloroquine as reference drug. Of the sixteen extracts, four showed activity against P. falciparum with IC50 ranging between 1.47 µg/mL and 7.32 µg/mL. Extracts prepared from stored material at -20 °C showed no antiplasmodium activity. The four originally active extracts were re-screened six months later, but the antimalarial activity could not be reproduced. To determine discrepancy in biological results, chemical profiling of the extracts was done using high performance liquid chromatography technique. Differences were observed in the profiles of the active extracts when compared to those of stored plant material. The instability of plant constituents observed could be a result of plant storage suggesting that the plant is best used when fresh.
Mostrar más [+] Menos [-]A socio-economic approach to One Health policy research in southern Africa
2012
Kim A. Kayunze | Angwara D. Kiwara | Eligius Lyamuya | Dominic M. Kambarage | Jonathan Rushton | Richard Coker | Richard Kock | Mark M. Rweyemamu
One-health approaches have started being applied to health systems in some countries in controlling infectious diseases in order to reduce the burden of disease in humans, livestock and wild animals collaboratively. However, one wonders whether the problem of lingering and emerging zoonoses is more affected by health policies, low application of one-health approaches, or other factors. As part of efforts to answer this question, the Southern African Centre for Infectious Disease Surveillance (SACIDS) smart partnership of human health, animal health and socio-economic experts published, in April 2011, a conceptual framework to support One Health research for policy on emerging zoonoses. The main objective of this paper was to identify which factors really affect the burden of disease and how the burden could affect socio-economic well-being. Amongst other issues, the review of literature shows that the occurrence of infectious diseases in humans and animals is driven by many factors, the most important ones being the causative agents (viruses, bacteria, parasites, etc.) and the mediator conditions (social, cultural, economic or climatic) which facilitate the infection to occur and hold. Literature also shows that in many countries there is little collaboration between medical and veterinary services despite the shared underlying science and the increasing infectious disease threat. In view of these findings, a research to inform health policy must walk on two legs: a natural sciences leg and a social sciences one.
Mostrar más [+] Menos [-]Impact of HIV and AIDS on food security in Rufiji District, Tanzania
2012
Kim A. Kayunze
Relatively high prevalence of HIV and AIDS and food insecurity in Rufiji District whilst the linkage between the two problems was not known was the basis of this study. Data were collected amongst 225 households between November 2005 and October 2006 through participatory rural appraisal (PRA), household income and expenditure survey (HIES) and structured interviews. Binary logistic regression was used for analysis in which case the dependent variable was food security in terms of food insecure (0) and food secure (1) based on kilocalories consumed per adult equivalent per day. The independent variables included having been affected by HIV and AIDS in terms of not affected (0) and affected (1). The results reveal that the odds for households affected by HIV and AIDS to be food secure were 0.705 times as high as the odds for households not affected by HIV and AIDS to be food secure. This means that households affected by HIV and AIDS were less likely to be food secure as opposed to those not affected by HIV and AIDS. The B statistic for having been affected by HIV and AIDS was negative (B = -0.350) meaning that being affected by HIV and AIDS had negative impact on food security. However, the Wald statistic which shows the magnitude of impact was small (0.251) and not significant (p = 0.617). This shows that HIV and AIDS had little impact on food security. Based on these findings, it is concluded that although being affected by HIV and AIDS has negative impact on food security, it does not automatically make households food insecure, especially in a short run, and that some non-HIV and AIDS factors like high dependency ratio and low ability to buy food have bigger negative impact than that of HIV and AIDS on food security. On the basis of the conclusion, it is recommended that efforts to improve food security amongst households affected by HIV and AIDS should consider both HIV and AIDS and non-HIV and AIDS factors.
Mostrar más [+] Menos [-]Human cystic echinococcosis in South Africa
2012
Benjamin Mogoye | Colin N. Menezes | Martin P. Grobusch | Kerstin Wahlers | John Frean
Cystic echinococcosis (CE) is caused by the tapeworm, Echinococcus granulosus. The tapeworms resides in the small intestines of canids and the lifecycle involves both intermediate and definitive hosts. Humans are accidental intermediate hosts. Cystic echinococcosis is an economically important infection constituting a threat to public health, and is considered an emerging disease around the world. There are at least 10 Echinococcus strain types (G1 – G10), each exhibiting diversity of morphology, development and host range. The epidemiology of CE is poorly understood in South Africa. A retrospective data analysis of the National Health Laboratory Service (NHLS) laboratory information system on echinococcosis serology, microscopy and histopathology results in eight provinces (excluding KwaZula-Natal) showed an overall positivity rate in submitted diagnostic samples of 17.0% (1056/6211), with the Eastern Cape (30.4%), North West (19.0%) and Northern Cape (18.0%) provinces showing highest rates. The data showed considerable variability between provinces. The review also showed that most proven cases were negative on serology, implying that the actual number of patients could be underestimated. To our knowledge, no data exist about the prevalent strains of E. granulosus and this prospective study will attempt to fill that gap. The aim is to genotype strains causing the disease in South Africa. Two different polymerase chain reaction (PCR) methods will be used to respectively target the 12S rRNA and nad 1 genes. To date, three samples have been genotyped as G1, G5 and G6; suggesting diversity of strains prevalent in the country, but more data is needed for a clearer picture.
Mostrar más [+] Menos [-]<i>In vitro</i> anti-tick properties of the essential oil of <i>Tagetes minuta</i> L. (Asteraceae) on <i>Hyalomma rufipes</i> (Acari: Ixodidae)
2012
Felix Nchu | Solomon R. Magano | Jacobus N. Eloff
In this study we examined the anti-tick properties of the essential oil of Tagetes minuta L. (Asteraceae: Asterales) against Hyalomma rufipes ticks. We obtained the essential oil of T. minuta by hydro-distillation of a combination of fresh flowers, leaves and soft stems, and analysed these by using gas chromatography (GC) and gas chromatography-linked mass spectrometry (GC-MS). The oil had a high percentage of monoterpenes and the major compounds identified were cis-ocimene (28.5%), beta-ocimene (16.83%) and 3-methyl-2-(2-methyl-2-butenyl)-furan (11.94%). Hyalomma rufipes adults displayed a significant (P < 0.05) dose repellent response to the essential oil of T. minuta. Probit analysis indicated a repellent EC50 of T. minuta essential oil for male ticks to be 0.072 mL/mL (CI 0.053 mL/mL to 0.086 mL/mL) and 0.070 mL/mL (CI 0.052 mL/mL to 0.084 mL/mL) for female ticks. There were no significant differences in repellent responses between male and female ticks. The oil also significantly (P < 0.05) delayed moulting of 60% of H. rufipes engorged nymphs. These results suggest that T. minuta may be a potential source of anti-tick agents.
Mostrar más [+] Menos [-]Infectious diseases of economic importance: Molecular biological characteristics of foot-and-mouth disease viruses collected in Tanzania from 1967 to 2009
2012
Christopher J. Kasanga | R. Sallu | C.A.R. Mpelumbe-Ngeleja | J. Wadsworth | N.P. Ferris | G.H. Hutchings | P.P. Wambura | M.G.S. Yongolo | N.J. Knowles | Donald P. King | M.M. Rweyemamu
Foot-and-mouth disease (FMD) is endemic in Tanzania. Since the first reports in 1954, FMD has caused significant economic losses in the country due to mortality and morbidity of livestock and costs associated with controlling the disease. The aim of this study was to review the serotype and genetic relationships of the FMD virus (FMDV) recovered from outbreaks in Tanzania, and compare them with viruses detected from elsewhere in the sub-Saharan region. At the World Reference Laboratory for foot-and-mouth disease (WRLFMD), a total of 106 FMD viruses have been isolated from samples collected between 1967 and 2009 from northern, southern, eastern and central parts of Tanzania. The presence of FMDV was determined by laboratory methods such as VI, CF, antigen ELISA and RT-PCR. Phylogenies of VP1 sequences were determined by the Neighbour-joining method. Foot-and-mouth disease virus SAT1 was the most frequent serotype (46.2%; n = 49) isolated in Tanzania followed by O (26.4%; n = 27), A (14.1%; n = 15) and SAT 2 (11.3%; n = 13). Genotyping showed that type O viruses fell into either the EAST AFRICA 1 (EA-1) or EA-2 topotypes, type A’s into the AFRICA topotype (genotype I), type SAT 1’s into topotype I and type SAT 2’s into topotype IV. This study reveals that serotypes A, O, SAT1 and SAT2 cause FMD outbreaks in Tanzania. Recent samples from outbreaks in 2008, 2009 and 2010 have been typed as serotypes A, O, SAT1 and SAT2. Phylogenetic analysis of FMDV isolates from Tanzania showed that they are genetically related to lineages and topotypes from West and East Africa. In Tanzania, lack of comprehensive animal movement records and inconsistent vaccination programs 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, together with improved local epidemiological investigation of FMD outbreaks is required to elucidate the complex epidemiology of FMD in the sub-Saharan region.
Mostrar más [+] Menos [-]A foresight vision for infectious diseases in Africa
2012
Joe Brownlie
A foresight vision for infectious diseases in Africa
Mostrar más [+] Menos [-]Economic benefits or drivers of a ‘One Health’ approach: Why should anyone invest?
2012
Jonathan Rushton | Barbara Häsler | Nicoline de Haan | Ruth Rushton
One Health concepts and ideas are some of the oldest in the health discipline, yet they have not become main stream. Recent discussions of the need for One Health approaches require some reflection on how to present a case for greater investments. The paper approaches this problem from the perspective of the control and management of resources for health in general. It poses the following questions, (1) where do we need extra resources for One Health, (2) where can we save resources through a One Health approach and (3) who has control of the resources that do exist for One Health? In answering these questions three broad areas are explored, (1) The management and resources allocated for diseases, (2) The isolation of parts of the society that require human and animal health services and (3) The use of resources and skills that are easily transferable between human and animal health. The paper concludes that One Health approaches are applicable in many scenarios. However, the costs of getting people from different disciplines to work together in order to achieve a true One Health approach can be large. To generate tangible benefits requires careful management of specialist skills, knowledge and equipment, which can only be achieved by a greater openness of the human and animal health disciplines. Without this openness, policy makers will continue to doubt the real value of One Health. In summary the future success of One Health is about people working in the research, education and provision of health systems around the world embracing and managing change more effectively.
Mostrar más [+] Menos [-]Seroprevalence of leptospirosis in dogs in urban Harare and selected rural communities in Zimbabwe
2012
Solomon Dhliwayo | Gift Matope | Lisa Marabini | Keith Dutlow | Davis M. Pfukenyi
A cross-sectional study was conducted to investigate seroprevalence of canine leptospirosis in urban Harare and five selected rural communities in Zimbabwe and to assess public awareness of the disease. Sera from randomly selected dogs were tested for antibodies to the serovars Canicola, Grippotyphosa, Icterohaemorrhagiae and Pomona of <em>Leptospira interrogans</em> using an enzyme-linked immunosorbent assay. Clinical chemistry was performed on all seropositive and selected seronegative sera to screen for hepatic and renal insufficiency. A questionnaire- based survey was conducted in Harare to assess dog owners’ awareness of leptospirosis and other zoonoses. Overall, 15.6% of sera samples tested (39 out of 250; 95% confidence interval [CI]: 11.0% – 20.2%) were positive for leptospiral antibodies. A significantly higher (<em>p</em> < 0.05) seroprevalence was recorded in urban dogs than in rural dogs (25% vs. 11.2%). No significant difference in seroprevalence was observed amongst dogs from different rural communities or between sexes of dogs. There was a significant association between seropositivity and hepatic and/or renal insufficiency (<em>p</em> < 0.01), with dogs having hepatic and/or renal insufficiency being approximately twice as likely to be seropositive (relative risk = 1.96; 95% CI: 1.3–3.0). Of the dog owners, 78.8% (119/151) were aware of zoonoses. Except for rabies (92.4%), awareness of leptospirosis (5.0%) and other zoonoses amongst these owners was low. This study showed that leptospirosis was present and represented a risk to dogs from urban Harare and the selected rural communities in Zimbabwe. Availing training programmes for dog owners would be beneficial in improving disease control and reducing the public health risk of pet zoonoses.
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