Antifungal activity of four weedy plant extracts against selected mycotoxigenic fungi.

AIMS: To investigate the antifungal activity of aqueous and organic extracts of four weedy plant species viz. Tagetes minuta, Lippia javanica, Amaranthus spinosus and Vigna unguiculata against isolates of four agriculturally important fungi, i.e. Fusarium verticillioides, F. proliferatum, Aspergillus flavus and A. parasiticus. METHODS AND RESULTS: Dried powdered aerial parts of the plants were extracted sequentially with hexane, dichloromethane, methanol and water and tested for activity using a serial microdilution assay. Results were read every day over 120 h. All extracts except for the water extracts showed growth inhibitory activity against most isolates of the Fusarium spp. The most active were the methanol and hexane extracts of V. unguiculata and A. spinosus with minimum inhibitory concentration (MIC) values of <0.5 mg ml(-1) after 48 h against Fusarium spp. No inhibition of the Aspergillus spp. tested was observed, but conidium formation was stimulated on plates treated with plant extracts when visually compared to the growth controls. CONCLUSIONS: The results obtained from this study indicated that chemical constituents from these plant species may be developed as potential agrochemical fungicides. SIGNIFICANCE AND IMPACT OF THE RESEARCH: Food and feed are subject to infection by a variety of micro-organisms that can induce spoilage and/or produce metabolites that are toxic to humans and animals. Extracts of V. unguiculata and A. spinosus were most active and maybe developed into environmentally friendly fungicides, which are affordable to rural farmers in developing countries.

Antibacterial activities of medicinal plants used for the treatment of diarrhoea in Limpopo Province, South Africa.

The ethnobotanical survey conducted in this study showed that 21 plant species belonging to 14 families are used in traditional medical practice in Limpopo Province, South Africa, for the treatment of diarrhoea. Methanol, ethanol, acetone and hot water extract from different plant parts (leaves, roots, bark and stem rhizome), of several of these plants (Indigofera daleoides, Punica granatum, Syzygium cordatum, Gymnosporia senegalensis, Ozoroa insignis, Elephantorrhiza elephantina, Elephantorrhiza burkei, Ximenia caffra, Schotia brachypetala and Spirostachys africana), were screened for antibacterial activity against Vibro cholera, Escherichia coli and Staphylococcus aureus, Shigella spp., Salmonella typhi. The antibacterial activity was determined by agar-well diffusion method and expressed as the average diameter of the zone of inhibition of bacterial growth around the wells. The minimum inhibitory concentration (MIC) of active extracts was determined by using the micro-plate dilution assay. Most of the extracts showed relatively high antibacterial activity against most of the tested microorganisms with the diameter of inhibition zones ranging between 10 and 31 mm. Of the plants studied, the most active extracts were those obtained from Punica granatum and Indigofera daleoides. All extracts from two plants, namely, Punica granatum and Ozoroa insignis, were active against all bacterial strains while only organic extracts of Indigofera daleoides inhibited the growth of all tested microorganisms. Water extract of Punica granatum were equally active as organic extracts against bacteria such as Staphylococcus aureus, Shigella sonnei and Shigella flexneri. All extracts of Elephantorrhiza elephantina, Elephantorrhiza burkei and Ximenia caffra and Schotia brachypetala were not active against Escherichia coli and Salmonella typhi. The MIC values for active extracts ranged between 0.039 and 0.6 mg/ml. The results obtained appeared to confirm the antibacterial potential of the plants investigated, and their usefulness in the treatment of diarrhoea.

Ethics and HIV research in Zimbabwe.

A plethora of articles are now being published in both local and international journals on research activities conducted on the human immunodeficiency virus (HIV) in Zimbabwe. Some of the bioethical issues they raise, however, are neither unique to HIV nor unique to developing countries. In this article we discuss several of these issues, including the failure to provide interventions of known efficacy, ethical relevance of study design, informed consent, and exploitation. A challenge raised by much of the research in HIV/AIDS is whether, or under what conditions, it is ethical in research to fail to provide an intervention of known efficacy. The further we diverge from this situation, in which an effective, easy to implement intervention is available, to situations that resemble the controversial international clinical trials to prevent perinatal transmission of HIV the less clear the ethical mandate becomes. In relation to clinical trials the debate has focused on whether the standard of care in the United States--an expensive and complex regimen of Zidovudine--must be provided to all HIV infected pregnant women who join a research study in developing countries. Different scientists and scholars in bioethics have drawn the line differently in terms of what interventions routinely available in the developed world must be provided to research participants in developing countries. At an extreme, no one suggests that the most expensive and complex of Western tertiary care, for example, renal dialysis or coronary bypass, must be provided in research conducted in Zimbabwe. Indeed, public debates about the HIV perinatal transmission trials have not even focused on whether the women in the trials should be provided with HIV combination therapy as they would be in the West or whether they should even have the Zidovudine continued post partum.

Antiretrovial (ARV) drug utilisation in Harare.

OBJECTIVE: To investigate ARV utilisation in Harare in order to gather necessary data to help in the formulation of treatment guidelines to be used in Zimbabwe. DESIGN: A cross sectional study. SETTING: Doctors' rooms and retail pharmacy outlets. SUBJECTS: 68 primary care physicians, 80 pharmacists and 92 patients. MAIN OUTCOME MEASURES: Number of physicians prescribing antiretroviral agents (ARVs) and pharmacists stocking ARVs. Type of ARV utilised, cost to the patient and information on ARV available. RESULTS: Out of the 68 private practitioners interviewed 18 were prescribing ARVs during the period of study. There were 92 patients on ARVs whose mean age was 35 +/- 5 years and consuming an average total of 17 tablets daily. Thirteen out of the 18 doctors had access to laboratory facilities to determine CD4 counts and viral load. The rest were using other approaches to treat and manage HIV/AIDS patients. About a quarter, 27.0%, of the retail pharmacists stocked ARVs. The majority, 82.0%, of the patients appeared to be on Zidovudine (AZT) mainly in combination with other drugs. The most popular combination was that of AZT, Lamivudine (3TC) and Indinavir prescribed to 29.0% of the patients, followed by that of Didanosine (DDI) and hydroxyurea prescribed to 17% of patients. At least 17% of the patients were on AZT monotherapy. There was no significant difference (p = 0.06) in the number of tablets consumed by patients who had other conditions secondary to HIV infection. Only 39 out of the 92 patients reported untoward experiences with ARVs. The major problem being associated gastro-intestinal disturbance which accounted for 56% of the reports. It was not possible to ascertain adherence. CONCLUSION: There appeared to be therapeutic anarchy in the private sector in Harare in the way ARVs were being used. Patients need to be told that deciding to take one of the combinations means making a serious commitment to the drugs on schedule if they want to enjoy the benefit. At the same time there is need to develop and publicize HIV/AIDS treatment guidelines and effective Information, Education and Communication (IEC) materials specific to Zimbabwe.

People's perceptions about malaria transmission and control using mosquito repellent plants in a locality in Zimbabwe.

OBJECTIVE: To assess peoples' perceptions and knowledge about malaria transmission and control with special reference to the use of plants as mosquito repellents. DESIGN: Cross sectional study. SETTING: Mandeya ward "A" (33 degrees E and 18 degrees 30' S), Honde Valley, Zimbabwe. SUBJECTS: 226 household heads present when interview was conducted. MAIN OUTCOME MEASURES: Mosquito control methods, spraying coverage, plants used to repel mosquitoes and reasons for using them. RESULTS: 215 (95.0%) of the respondents' homes had been sprayed and their understanding of malaria transmission was not related to compliance with the National Malaria Control Programme (NMCP). Taking mosquito control measures was related to knowledge of malaria transmission, with 24 (75.0%) of those who did not know, taking no measures of their own. The use of plants was mentioned by 50 (23.5%) of the respondents and the reasons given were that they were cheap 43 (86.0%), effective five (10.0%) and locally available two (4.0%). The plant which was mentioned as being used by all age groups was L. javanica 25 (50.0%) and the other plants were used to a lesser extent. Forty six (92.0%) of the people said that they had used plants for mosquito control. The leafy part of the plant was used by 43 (86.0%) and a fresh preparation 43 (86.2%) gave better protection than a dry one. The plants were crushed and applied on the skin by eight people (14.6%), burnt by 36 people (72.8%) and used in their original form by six people (12.6%) and used once per by day 42 people (84.0%). CONCLUSIONS: One of the important points to emerge from this study is that, despite widespread knowledge about the morbidity of malaria, understanding about its prevention was generally low and this has negative implications on an integrated control programme.

Bioavailability of rifampicin in a separate formulation and fixed dose combination with isoniazid NIH: a case for a fixed dose combination (FDC) for the treatment of tuberculosis.

OBJECTIVES: To study and compare the bioavailability of rifampicin (RIF), in two locally manufactured formulations; an FDC and a separate formulation and an imported FDC formulation. DESIGN: Open within subjects, single blind cross over study. INTERVENTIONS: Each volunteer subject, acting as their own control, received the two fixed dose combinations and the separate formulation with the same amount of 450 mg RIF. MAIN OUTCOME MEASURES: Cmax (peak drug concentration achieved), Tmax (time at which peak drug concentration is achieved), T1/2el (biological half-life of elimination) and area under the curve (AUC) for zero to 10 hours and zero to infinity. These are obtained from plotting plasma concentration against time. RESULTS: There was a significant difference in the Cmax between free and RIF combined with INH (6.1 and 7.6 mg/l respectively) and no significant difference in the other parameters measured, of the local products. Comparison of the local products and imported product showed no significant difference in AUC but significant differences in T1/2el, C max and Tmax (p = 0.003, 0.041 and 0.025 respectively). CONCLUSION: The Zimbabwe manufactured and the German products had "demonstrable bioavailability" as defined by the International Union Against Tuberculosis and Lung Diseases (IUATLD). The local manufacturer appeared to have the technological capability to produce a registrable combined RIF/INH table to be used in the treatment of tuberculosis and to prevent the irrational use of RIF.

The impact of health education on the knowledge, attitudes and practices of a rural community with regards to schistosomiasis control using a plant molluscicide, Phytolacca dodecandra.

OBJECTIVE: To determine the impact of health education on knowledge, attitudes and practices (KAP) with regards to use of a plant molluscicide in snail control. DESIGN: Repeat cross sectional survey. SETTING: Chiweshe communal lands. SUBJECTS: Males and females--age range 13 to 87 years. MAIN OUTCOME MEASURES: Changes in: KAP after health education, water usage pattern, water contact behaviour, willingness to participate in use of P. dodecandra. RESULTS: A high proportion of the community indicated prior knowledge of schistosomiasis during both knowledge, attitudes and practices (KAP) surveys. In the follow up KAP survey changes in the community's water contact behaviour as well as their practices in relation to sanitation were reported. The involvement of the community in the application of P. dodecandra during the course of the study ensured continued support and participation of the community. This was evidenced in the follow up survey when it was apparent that the community's attitude towards schistosomiasis had been influenced by the different activities that had taken place. CONCLUSION: Changes in the community's KAP with regards to schistosomiasis control, can be interpreted as an indication of the impact of the health education delivered during the course of the study. Health education should, therefore, precede programmes that require full participation of the community, as this enables the community to make informed decisions regarding their participation.

TB infection: an exploratory study of BCG protective properties and the possible role of environmental mycobacteria.

OBJECTIVE: To evaluate the presence of environmental mycobacterial strains and explore the implications for BCG vaccination against TB. DESIGN: Multimethod approach which included structured interviews and medical records examination. Soil and water samples were analysed using standard microbiology methods. SETTING: Beatrice Infectious Diseases Hospital, Public Health laboratories, University of Zimbabwe Medical School and several residential areas in Harare. SUBJECTS: 129 tuberculosis inpatients at Beatrice Infectious Diseases Hospital, 26 Public Health Laboratory technicians handling TB specimens and 51 fourth year medical students. MAIN OUTCOME MEASURES: Vaccination status of TB inpatients, medical students and laboratory technicians, protective efficacy of BCG in all subjects, presence of environmental mycobacterium in the environment. RESULTS: The type of tuberculosis did not differ significantly between vaccinated and non-vaccinated TB patients x2(df = 1) = 0.171 p > 0.05. There was no apparent difference between the revaccinated and non-vaccinated laboratory technicians. One respondent out of each of the revaccinated and non-vaccinated laboratory technicians had developed pulmonary tuberculosis. Among the fourth year medical students, four had positive tuberculin test results, even though they had not been vaccinated at the University clinic. Environmental mycobacteria presumptively identified as Mycobacterium scrofulaceum and Mycobacterium intracellulare were isolated from both the water and soil samples taken from a few selected areas in Harare. Of the 129 TB in-patients, 88 (68.2%) had previously been vaccinated against TB. Similarly among the 51 medical students 44(86.3%) had been vaccinated. Laboratory technicians re-vaccinated on the job were nine out of 26. CONCLUSION: The results obtained seemed to indicate that BCG protective efficacy did wane with time and revaccination appeared not to be useful. Environmental mycobacterium that could influence the BCG efficacy do exist in our environment.

Prevalence of gonorrhoea and knowledge of sexually transmitted infections in a farming community in Zimbabwe.

OBJECTIVE: To determine the prevalence of gonorrhoea and knowledge about sexually transmitted infections in a farming community. DESIGN: Cross sectional study. SETTING: Commercial farming area, Zimbabwe. SUBJECTS: 1,005 individuals aged between 15 and 60 years. MAIN OUTCOME MEASURES: Prevalence rates, knowledge of gonorrhoea and other sexually transmitted infections (STIs) by age and sex. RESULTS: Knowledge of gonorrhoea and other STIs was higher while knowledge of AIDS was lower among males than females. Frequency of past history of STIs in five years was significantly higher among males than females (OR 3.22; 95% CI 2.45 to 4.25). Physical examination revealed that 14% of males and 22% of females had other STIs besides gonorrhoea. The prevalence of gonorrhea was 18.4% (95% CI 16.0 to 20.8) and was higher among females than males (OR 2.77; 95% CI 1.97 to 3.90). Thirty one percent of the gonorrhoea infections were due to penicillinase producing Neisseria gonorrhoeae. CONCLUSIONS: Our findings emphasize the disparity between knowledge and practices with regards to STIs, and the importance of STIs as potential targets for and indices in the fight against human immunodeficiency virus (HIV) infection.

PIP: A cross-sectional study of 1005 males and females 15-60 years of age from a commercial farming community (Hippo Valley Sugar Estates) in Zimbabwe investigated knowledge and prevalence rates of gonorrhea and other sexually transmitted infections (STIs). Although over 70% of respondents were aware of gonorrhea, only 45.5% were knowledgeable about AIDS. Males had higher knowledge of gonorrhea and other STIs than females, but lower knowledge of HIV/AIDS. 47% of subjects had a history of an STI in the 5 years preceding the study. The frequency of such a history was significantly higher among males compared to females (odds ratio (OR), 3.22; 95% confidence interval (CI), 2.45-4.25). Physical examination indicated that 20.5% of males and 37.9% of females had signs of STIs. The majority of STI cases affected men in the 20-29 year age group and women 30-39 years of age. Gonorrhea prevalence was 18.4% and significantly higher among females than males (OR, 2.77; 95% CI, 1.97-3.90). 31% of gonorrhea infections were associated with penicillinase-producing Neisseria gonorrhoeae. Since STIs have been associated with increased transmission of HIV, these infections should be targeted for campaigns aimed at reducing the disparity between knowledge and practices. Moreover, examination of the prevalence of STIs such as gonorrhea is a quick way of assessing the impact of HIV control measures in a community.

Assessment of environmental pollution by PCBs, DDT and its metabolites using human milk of mothers in Zimbabwe.

The milk samples were collected from mothers who had lived in the area for at least 5 years, healthy and breast feeding their first, second or third child. Of the 175 mothers' milk samples analysed, the organochlorine pesticide residues were detected in the following order of frequency: pp-DDE, 100%, pp-DDT 98%; and sum PCB, 53%. Of all the seven areas analysed the Kariba area and the highest mean level of sum DDT--25,259 ng/g milk fat and the lowest mean level of sum DDT of 1607 ng/G milk fat was found in Esigodini which is a rural area. The major DDT metabolite was pp-DDE. The ratio of pp-DDT/pp-DDE was highest in Kariba (0.6) suggesting recent pollution by DDT in that area. The results show that the vector control programmes (extensive pesticide spraying of disease-carrying pests, such as mosquitoes and tsetse flies), agricultural activities and dietary habits were the main contributing factors towards the high levels of pesticides in most of the areas. Kadoma area had the highest mean level of sum-PCB (60 ng/g milk fat).

Immunopharmacological aspects of praziquantel.

A possible synergy has been shown between chemotherapy with praziquantel, PZQ (normally administered once in 12 months), and the immune system in mice infected with schistosomiasis. This has been supported by a reduction in the effectiveness of PZQ against adult schistosomes in T and B lymphocyte depleted mice. We have investigated the effect of a standard dose, 40 mg/kg, of PZQ on polymorphonucluecytes (PMN) spreading, granulocytes chemotaxis, adherence and lymphocyte blastogenic responses. Blood samples were collected from volunteer children with or without urinary schistosomiasis infection, after obtaining their consent. The results obtained showed that PZQ, three hours after administration (plasma half life; 1.5 h), appeared to significantly (p < 0.001) enhance the chemotactic affect of N-fmlp and the blastogenic effect of soluble schistosome egg antigen (SEA) and phytohaemaglutanin (PHA). It would be reasonable to conclude that these observed effects of PZQ may contribute to the overall mode of action of PZQ.

Schistosomiasis and hepatitis B infection in pregnancy: implications for vaccination against hepatitis B.

A study to investigate the prevalence of schistosomiasis and hepatitis B viral (HBV) infection, among pregnant women was carried out at Howard Hospital in Chiweshe District, Zimbabwe. Urine and stool specimens, for the determination of Schistosoma haematobium and Schistosoma mansoni respectively, were collected from 299 pregnant women attending an antenatal clinic. In addition, five ml of blood was collected from each of the women for the determination of hepatitis B serum markers, HBsAg and anti-HB antibodies. S. haematobium and S. mansoni infection prevalence was 50 pc among the pregnant women. About 13 pc of them had both infections. Frequency of stillbirth or infant mortality was 16 pc among expectant mothers who previously had schistosoma infection compared to 8 pc among those who had no history of schistosomal infection. Only 2 pc of the pregnant women tested positive for the two hepatitis B markers. However, further hepatitis B prevalence B studies still have to be carried out with a larger cohort of pregnant women in schistosomiasis endemic areas. At the same time the seroconversion rates of children born from mothers living in schistosomiasis endemic areas would need to be compared with those of non-endemic areas before any changes in the recommended vaccination schedule are made.

In vitro activity of several antimicrobial agents against Neisseria gonorrhoeae and comparison of cost of treatment.

During a cross sectional study on the prevalence and incidence of gonorrhoea, Neisseria gonorrhoeae was isolated from 185 people aged between 16 and 60 years. In vitro activity of six antimicrobial antibacterial agents, penicillin, erythromycin, tetracycline, cotrimoxazole, ceftriaxone and norfloxacin on the isolated N. gonorrhoeae were carried out. The results obtained showed that, of all 111 isolates, 48 (43.2 pc) were penicillinase producing N. gonorrhoeae (PPNG) and 63 (56.8 pc) were non PPNGs. Over 90 pc of both PPNG and non PPNG isolates were sensitive to tetracyline and erythromycin. Seventy five pc of the PPNG and 45 pc non-PPNG were not sensitive to two units of penicillin. Both PPNG and non-PPNG were less sensitive to cotrimoxazole 25 micrograms. Norfloxacin and ceftriaxone were over 70 pc effective but were extremely expensive for most people who got infected.

Morphine induced, behavioural, biochemical and immunological correlations.

Tolerance and dependence on morphine appear more or less simultaneously. Evidence has accumulated that addiction leads to depressed immune function and seem to suggest that dependence is under genetic influence. Morphine and related substances of abuse open perspective on ways to investigate the basic mechanisms related to their cellular and systemic effects.

Layman's perception of antimicrobial agents: a challenge to health education strategy in Zimbabwe.

In many developing countries there has not been any systematic analysis of societal beliefs and attitudes towards drug entities, the meaning which is attributed to drugs and their effects and how such meanings might influence drug consumption and health seeking behaviour. It is in many developing countries that a lot of antimicrobial agents are available freely over the counter or on the street. This is said to make the assessment of the therapeutic outcome during their use often very difficult. The present study has shown that continued health education while at the same time paying attention to societal beliefs and attitudes towards infectious diseases and medicines used, is required. The specific aims must be to reinforce beliefs that facilitate appropriate use of antimicrobial agents and to discourage those that impede it.

Drug information for the community: type and source.

Patients' failure to adhere to a well-founded drug regimen is a recognised source of failure to treatment. This may be a result of a deliberate action by the patient or a misinterpretation or inadequate provision of information. By and large, live information sources tend to behave in a reactive fashion; they answer specific questions which patients ask. Similar to individualised drug dosages, information and subsequent communication need tailoring according to wide range of premises related to human beings. The present study on what type of information on drugs, people required, reports some thought provoking findings, for instance, a major fraction of people (70 pc) in the rural areas studied, did not request any information on their medication because health care providers had generally no time to discuss with their patients. Even worse others were thought to be extremely rude. Health care will continue to be inappropriate unless the care providers, at all levels, are able to understand their patients perceptions, by asking how they care about health and disease in general; whether they agree with the diagnosis and the need for the intervention recommended; and finally whether compliance with drug regimen is feasible.

Drug information for patients in the community.

The failure of patients to follow drug regimens may be due to lack of information or the negative attitudes of patients and health care providers. We have found that most patients in rural areas did not ask for information about their treatment because they felt their health carers had little time for such matters. These problems will continue unless practitioners at all levels make better efforts to understand their patients' perceptions of illness and treatment, and especially whether compliance with drug treatment is feasible.

PIP: The failure of up to half of all patients in developing countries to adhere to recommended drug regimens may reflect inadequate physician- provider communication rather than resistance to treatment. There is substantial evidence that patients are more likely to conform to treatment regimens when they are fully informed about their medical condition and the medication prescribed. To investigate the extent to which patients in Zimbabwe received this type of information, household heads in 910 households in the Mashonaland West Province were interviewed. The sample included equal numbers of respondents from urban, rural, and commercial farming areas. Diseases most commonly reported by rural residents and farmers were diarrhea, influenza, cough, hypertension, and malaria. Most of the illnesses were attributed to natural or supernatural causes, and 80% of respondents in these subsamples claimed to distrust their health care provider and never asked questions about medications prescribed. The rural residents perceived health care personnel as too busy to answer questions and did not believe they would understand any information offered. On the other hand, these respondents indicated they would like to have information on the cause of their illness, its duration and treatment, the best way to take prescribed drugs, actions to take when drugs produce side effects, and storage of medication. Physicians who treat semi-literate rural residents with indigenous health beliefs are urged to provide information about medication tailored to match the individual perceptions and needs of the patient. This need is less urgent in urban areas, where 60% of respondents had general knowledge about the action of various medicines and were able to obtain information from pharmacists.