Conjoint Professor David Durrheim

This study explored the Walhallow Aboriginal community's experiences with drinking water to gain a shared understanding about community concerns and to develop ways to address these concerns together. There is a strong connection between people and water, as well as a need to appreciate the social factors associated with the unique cultural and socioeconomic factors that the provision of drinking water has for Aboriginal communities. We used a mixed method design within a community-based participatory action Research (PAR) framework. Water hardness and parental influence were the key factors associated with participants' decisions to drink rainwater. This study provides important insights for water supply authorities when assessing health risks and when choosing appropriate mitigation measures for water quality improvement programs in Aboriginal communities.

BACKGROUND: Q fever remains an important occupational zoonosis in rural Australia. Although Q fever vaccine is recommended in high-risk occupational groups, its availability has been limited in recent years. METHOD: A literature review of the efficacy of the human Q fever vaccine registered in Australia was conducted. RESULTS: Seven relevant vaccine efficacy studies were identified but no large double-blind, randomised, placebo-controlled studies have been conducted. Vaccine efficacy has ranged from 83-100% but limitations of study designs hamper a precise estimate of vaccine efficacy. CONCLUSION: Despite the shortcomings of efficacy studies, the Q fever vaccine available in Australia has considerable protective benefit in established high-risk environments, particularly of an occupational nature.

INTRODUCTION: Irukandji syndrome, a potentially life-threatening condition that follows the sting of small carybdeid jellyfish, occurs along the northern Australian coastline from Broome, Western Australia in the west to Rockhampton, Queensland in the east. Much of this area is classified rural or remote. Because correct patient management is essential to avoid unnecessary fatality, and stings are relatively uncommon in any specific location, it was considered important to document current approaches to Irukandji syndrome management throughout coastal northern Australia, comparing urban and more rural health facilities, and to assess the availability of management guidelines for health staff. METHODS: A telephone survey of the clinicians responsible for Irukandji syndrome patient management at 34 coastal northern Australian health facilities that might encounter this patient presentation was conducted during November and December 2003. Healthcare providers responsible for Irukandji syndrome management on the day of survey were interviewed using a structured, standardized questionnaire, which included a description of a hypothetical patient with Irukandji syndrome. This was used to stimulate a spontaneous description of the usual response of the particular health facility to such a patient presentation. Additional vignettes were used to investigate further specific aspects of patient management, including first aid, and pain and blood pressure management. Respondents were also asked about the existence of Irukandji treatment guidelines at their facility. RESULTS: All 34 facilities contacted agreed to participate. Five health facilities were in urban centres with a population of 50,000 or greater, four were within 50 km of such centres, 20 were more remote and five facilities were on islands. Basic clinical monitoring (blood pressure, pulse, respiratory rate and oxygen saturation) was generally adequately practised. Topical application of vinegar as a first aid measure was described by 79% of respondents, with spontaneous mention of vinegar significantly associated with increasing remoteness (p = 0.023). Other sting site management was variable, with uncertainty about the use of pressure immobilisation bandaging. Intravenous opiate analgesia was administered at 91% of facilities, and magnesium sulphate, a treatment that is still being evaluated for its role in Irukandji syndrome-related pain and hypertension, was mentioned by 12% of respondents for pain relief. Twelve different pharmacological treatments were used for syndrome-associated hypertension, with magnesium sulphate being mentioned by 21% of respondents. Of the 22 facilities with guidelines, 14 used either the Primary Clinical Care Manual or the Central Australian Rural Practitioners Association Standard Treatment Manual. The remaining guidelines were independently produced protocols. The availability of guidelines was associated with appropriate use of intravenous opiate for adequate pain relief (p = 0.037). Although all urban health centres and 75% of health facilities <50 km away had guidelines, only 56% of more remote or island facilities reported the availability of guidelines. CONCLUSIONS: Although monitoring and pain management of patients with Irukandji syndrome were generally appropriate, a variety of inappropriate first aid and hypertension management approaches were found. In general, appropriate practice was associated with the presence of guidelines but, unfortunately, guidelines were less often present in remote health facilities. This is particularly important because the majority of respondents who reported no experience of managing Irukandji syndrome were located in more remote settings. There is a need for uniform, evidence-based guidelines, and mechanisms for effective dissemination of these guidelines with training for all health staff who may be required to manage Irukandji syndrome, particularly in remote areas of northern Australia.

Until recently, the TropBio antigen enzyme-linked immunosorbent assay and the immunochromatographic test rapid-card test were the only commercially available diagnostic tests for lymphatic filariasis. The new Brugia Rapid antibody-detection dipstick is a welcome addition, but there is an urgent need to develop more cost-effective, accurate and standardized immunological tests for use in the global filariasis elimination program.

Artemisinin-class Combination Therapy (ACT) remains the most plausible means by which the ambitious goal of halving malaria mortality by the year 2010 may be achieved. Convincing evidence of ACT efficacy in treating uncomplicated malaria now exists. ACT appears safe but most safety studies have been weak methodologically. Thus there is an acute need for sensitive ongoing pharmacovigilance. Limited availability of ACT in those countries most likely to benefit from its public health use, has resulted in allegations of 'medical malpractice' against the World Health Organization and Global Fund for AIDS, TB and malaria. The ethical principles of autonomy, sanctity of life, beneficence and justice are pertinent to the adoption of ACT as first-line therapy of uncomplicated malaria by endemic countries. © 2004 Elsevier Ltd. All rights reserved.

Background: Malaria control programmes utilising indoor residual spraying are only effective if a high coverage of targeted structures is achieved and an insecticide that is effective against the specific mosquito vector is correctly applied. Ongoing monitoring of spraying operations is essential to assure optimal programme performance and early corrective action, where indicated. Methods: Successful development and application of a computerised spraying operations management system in Mpumalanga Province, South Africa during 1998 resulted in its adaptation and introduction in neighbouring Maputo Province, southern Mozambique during 2000. The structure and components of this computerised management system are described, and its' operational benefit in southern Mozambique, where community-based spray operators apply intradomiciliary insecticide, are reviewed. Conclusions: The computerised management system allowed malaria programme management and field supervisors to monitor spraying coverage, insecticide consumption and application rates on an ongoing basis. The system supported a successful transition to community-based spraying, while assuring correct insecticide application and spraying completion according to schedule.

In 1993, the World Health Organisation (WHO) declared tuberculosis (TB) a global emergency and in 1996, South Africa declared TB as a priority disease. The most effective means of controlling TB is through rapid diagnosis by direct sputum microscopy for acid fast bacilli (AFB), or culture for Mycobacteium tuberculosis (MTB) and prompt initiation of the correct therapy by means of the Directly Observed Treatment, Short course (DOTS) strategy. ln 1997, it was estimated that 10 million of the 30 million people infected with the human immuno-deficiency virus (HM worldwide were co-infected with TB. This review article focuses on TB diagnosis, including newer laboratory tests, treatment, and chemoprophylaxis. Special issues such as extra pulmonary TB, childhood TB, BCG immunisation, and the deadly alliance between TB and HIV/AIDS are also considered. Tuberculosis is a treatable disease and the aim of any family practitioner should be to treat smear positive patients as soon as possible, and cure them at the first attempt.

The most effective way to infuriate an epidemiologist is to call a "prevalence rate" an "incidence rate", or vice versa. Unfortunately, this diabolical practice remains a common feature in print, during presentations at medical references and in conversations between medical colleagues. You may, ask whether this confusion of terminology deserves mention in this column. Our answer is an emphatic "yes"! An incorrect understanding of incidence and prevalence can have disastrous effects on planning, whether within an individual practice or a global public health programme.

In a previous article we discussed the value of determining the relative risk of developing a disease in relation to a specific exposure and thus its utility for assessing the exposure's etiological role in disease causation. This article focuses on attributable risk, another important measure, which assists us in determining what the impact would be of effectively intervening against a specific causative factor. It is determined by subtracting the risk in the unexposed group from the risk in the exposed group, that is, Risk (exposed) - Risk (unexposed). The underlying or background risk without the exposure is assumed to be the same in both groups. When the level of risk is the same in both groups, then the risk difference is 0 and one can conclude that the exposure makes no difference to the disease risk. However, if the risk difference is greater than 0, there is increased risk of the outcome in relation to the specific exposure under investigation. If it is less than 0, that is, a negative number, then the exposure under investigation would appear beneficial with a lower disease risk in the exposed group.

BACKGROUND: Malaria control programmes utilising indoor residual spraying are only effective if a high coverage of targeted structures is achieved and an insecticide that is effective against the specific mosquito vector is correctly applied. Ongoing monitoring of spraying operations is essential to assure optimal programme performance and early corrective action, where indicated. METHODS: Successful development and application of a computerised spraying operations management system in Mpumalanga Province, South Africa during 1998 resulted in its adaptation and introduction in neighbouring Maputo Province, southern Mozambique during 2000. The structure and components of this computerised management system are described, and its' operational benefit in southern Mozambique, where community-based spray operators apply intradomiciliary insecticide, are reviewed. CONCLUSIONS: The computerised management system allowed malaria programme management and field supervisors to monitor spraying coverage, insecticide consumption and application rates on an ongoing basis. The system supported a successful transition to community-based spraying, while assuring correct insecticide application and spraying completion according to schedule.

There is a growing appreciation that decisions on changing drug treatment policy should be based on robust evidence of drug effectiveness. No published information describing the process of decision making prior to malaria treatment policy changes or subsequent success in implementing treatment policy changes exists in South Africa. This retrospective study of the differential implementation of a policy change from chloroquine to sulphadoxine-pyrimethamine for first-line treatment of malaria in two South African provinces, Mpumalanga and Limpopo Province, sought to explore the change from the perspective of national and provincial policy makers and programme managers. Focus-groups discussions, in-depth interviews, participatory exercises and archival documentary analysis were conducted. Policy makers and programme managers mentioned the need for local efficacy data as a prerequisite for changing malaria treatment policy. However, drug efficacy data alone were not sufficient to ensure effective policy making or implementation in this study. An effective strategy identified for motivating a change in policy was emphasizing the potential negative consequences of failure to implement a treatment change. In both provinces it was recognized that, for a policy change to be successful and applied at peripheral levels, the proposed change had to have official sanctioning from credible sources. Physical removal of all previously recommended medication from public healthcare facilities appeared to be a key factor in ensuring successful implementation. Lessons learnt through this retrospective analysis may be of value to a number of countries in sub-Saharan Africa, considering policy change in response to rapidly increasing anti-malarial drug resistance. However, additional case studies of the process of malaria treatment policy change are urgently needed from other African settings to determine commonalities and optimize the efficiency of formulating and implementing malaria treatment policy changes.

Experience from successful global elimination programmes highlights the pivotal role of functional surveillance programmes for confirming cessation of local disease transmission. Lymphatic filariasis is targeted for global elimination by 2020 with an earlier target of 2010 for the Pacific Island countries. No surveillance protocol for confirming filariasis elimination in small island countries has yet been agreed evaluated. Currently recommended surveillance strategies for confirming lymphatic filariasis elimination are not ideal for small Pacific countries. Relying on occasional surveys to detect an increasingly rare health condition has inherent epidemiological weaknesses. Characteristics of effective surveillance for confirming filariasis elimination would include adequate sensitivity for detecting residual transmission, ongoing population scrutiny, and integration within a resource-sensitive system that includes other important conditions requiring public health surveillance. We propose that acute adenolymphangitis (ALA) may prove a suitable surveillance condition. ALA surveillance nested within a syndromic communicable disease surveillance programme implemented universally by health facilities may provide a solution to the current conundrum facing Pacific lymphatic filariasis elimination programmes and should be carefully evaluated.

Background: Much communicable disease control research has had little impact on local control programme policy and practice for want of an operational component. The operational research model - the systematic search for knowledge on interventions, tools or strategies that enhance programme effectiveness - is gaining recognition as an appropriate method for addressing perplexing questions within public health programmes. Methods: A series of operational research studies were conducted to refine malaria diagnosis in Mpumalanga Province, South Africa between 1995 and 1999. The grounded theory approach was used with groups of experienced Masters of Public Health students in South Africa and Australia to analyse a compilation of these studies for determining positive and negative attributes of operational research that affect its ability to influence communicable disease control policy and practice. Results: The principal positive attributes of the operational research studies were high local relevance, greater ability to convince local decision-makers, relatively short lag-time before implementation of findings, and the cost-effective nature of this form of research. Potential negative features elicited included opportunities forfeited by using scarce resources to conduct research and the need to adequately train local health staff in research methodology to ensure valid results and accurate interpretation of findings. Conclusions: Operational research effectively influenced disease control policy and practice in rural South Africa, by providing relevant answers to local questions and engaging policy-makers. This resulted in accelerated inclusion of appropriate measures into a local communicable disease control programme.

A plethora of scoring systems have evolved in medicine Ranks or scores are a common feature of quantitative research conducted by family practitioners. In addition ranking is prevalent in the laboratory, e.g. malaria parasitaemia ranked as 0, +, ++, or +++, and at the patient bedside, that is, grading the severity of stroke or leprosy lesions as mild, moderate or severe (+, ++, +++) or of a cancer as Stage l, ll, lll or lV.A convenient way of combining the ranks of a group of related criteria is the creation of an "index". Basic indices result from simply adding the individual ranks of all components, while more sophisticated indices provide individual weightings to each component before they are summed. lt is useful to create indices but they should be used with circumspection.We will use the Apgar scoring system, which is used for the evaluation of newborn babies, to highlight features commonly shared by indices that should always be explicitly considered before use.

The chi-square test is the most commonly used statistic test for investigating the differences between proportion arising from research. It helps to determine where two or more series of proportions are significantly different from one another or whether a single series of proportions differs from a theoretically expected distribution. In addition it allows us to test whether any observed relationship could simply be due to "chance". Proportions would obviously differ from sample to sample selected simply due to the play of chance. The chi-square test thus assists us in making this judgment in an explicit way, and is a measure of the difference between the proportions observed and those that would have been expected if the null hypothesis of no difference between groups had been true.

It is common in the medical literature to be inundated with "p" values in publications. But what do they mean? To interpret p values, it is important to understand the "null hypothesis". The majority of statistical analyses involve comparisons between groups of study participants, and the comparison of interest is often called the "effect". In general, the null hypothesis states that the results observed in the particular study are no different from what might have been expected as a result of chance alone. lt is often the opposite of the research hypothesis that leads to the study. Having set up the null hypothesis we then evaluate the probability that the observed data could have resulted from chance alone. lt is this probability that is called the "p value". In other words, the p value gives probability that the observed difference could have occurred by chance alone, assuming that in reality there is no difference between the populations. The smaller the p value, the more untenable is the null hypothesis. That is to say, a small p value of 0.0025 means that there is only a 25 in 10 000 probability (0.25%) that the observed difference is due to chance alone, assuming that in reality there is no difference.

FOR THE PAST FIVE YEARS, SOUTH AFRICA has seen a marked increase in notified malaria cases without a similar trend in Swaziland, which nestles between the two malarious South African provinces of KwaZulu-Natal and Mpumalanga. Swaziland and these provinces share a border with Mozambique, where malaria is holoendemic. The change from DDT to synthetic pyrethroids for intradomicillary residual spraying in South Africa may have been a contributory factor to this increase. The absence of a similar trend in Swaziland, where DDT continues to be used, adds weight to the ecological association between change in the use of insecticide and increase in malaria cases.

Background. In South Africa, as part of an effort to eliminate indigenous measles by 2002, vaccination campaigns were conducted in 1996-1997 targeting all children aged 9 months to 14 years; coverage was estimated at 85%. The impact of the campaigns on measles disease burden was evaluated in 1999. Methods. We analysed routine measles surveillance data and undertook a retrospective review of hospital registers in two of South Africa's nine provinces. Results. In Mpumalanga in the pre-campaign years (1992-1996), 4498 measles cases and 6 deaths were reported; 182 cases and no deaths were reported in 1997-1998. Hospital registers showed 1647 measles hospitalizations and 11 deaths in the pre-campaign period, and 60 hospitalizations and no deaths after the campaign (1997-April 1999). In Western Cape in pre-campaign years (1992-1997), 5164 measles cases and 19 deaths were reported; 132 cases and no deaths were reported in 1998. Hospital registers showed 736 measles hospitalizations and 23 deaths in the pre-campaign period, and 29 measles hospitalizations and no deaths post-campaign (1998-July 1999). Conclusions. Study findings indicate that reported measles cases, measles-related hospitalizations and deaths were considerably reduced in both provinces after the campaign compared with the pre-campaign period. Longer observation is needed to evaluate the long-term impact of the campaigns.

BACKGROUND: Much communicable disease control research has had little impact on local control programme policy and practice for want of an operational component. The operational research model - the systematic search for knowledge on interventions, tools or strategies that enhance programme effectiveness - is gaining recognition as an appropriate method for addressing perplexing questions within public health programmes. METHODS: A series of operational research studies were conducted to refine malaria diagnosis in Mpumalanga Province, South Africa between 1995 and 1999. The grounded theory approach was used with groups of experienced Masters of Public Health students in South Africa and Australia to analyse a compilation of these studies for determining positive and negative attributes of operational research that affect its ability to influence communicable disease control policy and practice. RESULTS: The principal positive attributes of the operational research studies were high local relevance, greater ability to convince local decision-makers, relatively short lag-time before implementation of findings, and the cost-effective nature of this form of research. Potential negative features elicited included opportunities forfeited by using scarce resources to conduct research and the need to adequately train local health staff in research methodology to ensure valid results and accurate interpretation of findings. CONCLUSIONS: Operational research effectively influenced disease control policy and practice in rural South Africa, by providing relevant answers to local questions and engaging policy-makers. This resulted in accelerated inclusion of appropriate measures into a local communicable disease control programme.

We have reviewed data on malaria cases collected routinely by both passive and active methods for the period 1987 to 1999. Malaria transmission in Mpumalanga was markedly seasonal and unstable, occurring between October and May, and was essentially influenced by both temperature and rainfall. Malaria control in the province is by a combination of residual intradomicillary spraying with synthetic pyrethroids and prompt effective therapy of cases at primary health-care clinics. The prevalence of malaria in the province decreased from east to west in direct relation to altitude, with the highest prevalence in the east (<600 m altitude) and decreasing towards the west (>600 m altitude). Although the number of notified cases has increased since 1993, with epidemics recorded in 1996 and 1999, the mortality ratio has remained under 0.5% of notified cases per annum. A large proportion (30%) of malaria cases was found in patients younger than 15 years and affected school attendance. The majority of malaria cases were in the economically active age group of 15-50 years. Current malaria control in the province should be continued and the development of additional tools such as insecticide-treated nets is recommended.

Introduction. Quinine therapy for 7 days remains the mainstay for treating hospitalised malaria cases in South Africa. However, limited resources, including available beds and staff, often result in early discharge of non-severe cases, with quinine tablets for outpatient use. The effectiveness of shorter course quinine therapy coupled with a long-acting antimalarial drug has never been established in Africa, in particular in a population without malaria immunity. Methods. A study was conducted to evaluate the effectiveness of a 3-day course of therapy with quinine sulphate (10 mg/kg 8-hourly) followed by a single dose of sulfadoxine-pyrimethamine (SP) according to weight category, before discharge, for 133 hospitalised patients with uncomplicated Plasmodium falciparum malaria at Shongwe Hospital, Mpumalanga province, between February and July 1998. Study endpoints included clinical recovery and parasitological cure, including polymerase chain reaction (PCR) 42 days after initiating treatment. Results. One hundred and thirty of 131 patients (99%) successfully followed up for 42 days demonstrated clinical and parasitological cure. The remaining patient, who had evidence of a recrudescent infection on PCR, was 1 of 61 patients who were still parasitaemic on discharge from hospital. Conclusion. The abbreviated course of quinine therapy coupled with a single dose of SP for the treatment of non-severe hospitalised cases of P. falciparum malaria, in an area with demonstrated low levels of SP resistance, was highly effective. This approach has potential benefits, including reduced duration of hospitalisation, fewer quinine-associated adverse events and protection against the evolution of quinine resistance by limiting unsupervised quinine therapy in the community. It may, however, be prudent to document a negative blood film before discharge from hospital.

Objectives. To assess therapeutic efficacy of sulfadoxine-pyrimethamine (SP) in treatment of uncomplicated Plasmodium falciparum malaria 3 years after introduction in Mpumalanga, South Africa. Setting. Tonga district with a population of 116 418 and subject to seasonal malaria, with an average annual incidence of 3 200 cases. Subjects. One hundred and nineteen malaria patients presenting to a sentinel surveillance clinic and recruited according to World Health Organisation (WHO) criteria. Methodology. Patients satisfying WHO inclusion criteria were treated with a single oral dose of SP and the response of infection to treatment in each patient was routinely monitored clinically and parasitologically on days 1,2,3,7, 14,21,28 and 42 post-treatment. One hundred and ten patients completed follow-up to day 42 or evidence of clinical or parasitological failure. Results. The cure rate at day 42 was 93.6% (103/110). Two patients (1.8%, RII) were early treatment failures on day 3, while recrudescence (4.5%, RI) occurred in 5 patients on day 28 (N = 3) and on day 42 (N=2). Conclusion. In Mpumalanga P. falciparum remains sensitive to SP, with no significant difference between the baseline cure rate (94.5%) and the cure rate in the present study (93.6%).

Distribution of biting sites on the human body by the malaria vector Anopheles arabiensis Patton (Diptera: Culicidae) was investigated near a source of mosquitoes in the Kruger National Park, South Africa. Eight adult male volunteers (2 teams × 2 pairs of subjects) conducted human bait collections while seated on camp chairs in the open-air, wearing only short trousers (no shirt, socks or shoes). Mosquito collections during 18.30-22.30 hours on five consecutive nights in April 1998 yielded a total of 679 An. arabiensis females biting subjects with or without their ankles and feet treated with deet insect repellent (15% diethyl-3-methylbenzamide, Tabard¿ lotion). On subjects whose feet and ankles were smeared with repellent, 160 An. arabiensis females were captured biting in 60 man-hours: 88.1% on the legs, 1.4% on the arms and 1.2% on other parts of the body, but none on the repellent-treated feet or ankles. On subjects without repellent treatment, 519 An. arabiensis were caught biting in 60 man-hours: 81.1% on feet and ankles, 16.4% on legs, 1.4% on arms and 1.2% on the rest of the body. For individual subjects, the reduction of An. arabiensis bites ranged from 36.4 to 78.2% (mean protection 69.2%). Results of this study confirm previous findings that, in this part of South Africa - inhabited only by wildlife - when people sit outside during the evening An. arabiensis prefers to bite their lower limbs: 97.5% below the knees. Overall, the number of bites by the malaria vector An. arabiensis was reduced more than three-fold (from 26 to 8/person/evening), simply by treating ankles and feet with a consumer brand of deet repellent. Whether or not this provides a satisfactory degree of protection against malaria risk would depend on the malaria sporozoite rate in the malaria vector population.

Malaria is a re-emerging disease in much of Africa. In response, the World Health Organization launched the Roll Back Malaria (RBM) initiative. One of six key principles adopted is the early detection of malaria cases. However, the importance of definitive diagnosis and potential value of field deployment of rapid malaria tests in RBM has been largely ignored. The Lowveld Region of Mpumalanga Province, South Africa, is home to a predominantly non-immune population, of approximately 850000 inhabitants, who are at risk of seasonal Plasmodium falciparum malaria. Malaria treatment in this area is usually only initiated on detection of malaria parasites in the peripheral bloodstream, as many other rickettsial and viral febrile illness mimic malaria. The malaria control programme traditionally relied on light microscopy of Giemsa-stained thick blood films for malaria diagnosis. This review summarizes operational research findings that led to the introduction of rapid malaria card tests for primary diagnosis of malaria throughout the Mpumalanga malaria area. Subsequent operational research and extensive experience over a four-year period since introducing the ICT Malaria Pf test appears to confirm the local appropriateness of this diagnostic modality. A laboratory is not required and clinic staff are empowered to make a prompt definitive diagnosis, limiting delays in initiating correct therapy. The simple, accurate and rapid non-microscopic means now available for diagnosing malaria could play an important role in Rolling Back Malaria in selected areas.

Field assessment of the residual effect of deltamethrin (20 mg/m2) against Anopheles arabiensis (Diptera: Culicidae) mosquitoes was performed during evaluation of the malaria vector control programme in Mpumalanga Province, South Africa. Ten treated sleeping rooms, five of which were mud- and five cement-walled, were used in bioassays with laboratory-reared An. arabiensis. The bioassays were run for seven consecutive months after treatment. Seven months after treatment deltamethrin-treated surfaces were still completely effective against the susceptible strain of An. arabiensis, with a 24-hour holding mortality of 100%.

Cholera is a severe diarrhoeal illness caused by certain strains of Vibrio cholerae, which can lead rapidly to dehydration and death. Communities dependent on water contaminated with human faeces and those with poor sanitation are very vulnerable to cholera epidemics. Although the Vibrio cholerae Ol El Tor strain presently circulating in southern Africa is multi-drug resistant and currently available vaccines offer inadequate proteccion, cholera can be pre-vented by simple cost-effective measures, including chlorination or sustained boiling of drinking water. The key to cholera management is aggressive fluid replacement with the correct fluids. The latter strategy is so effective that a cholera death may be viewed as a health system failure deserving formal review. The only sustainable solution to the scourge of cholera is fundamental economic and social development with the provision of safe water and adequate sanitation.

After good quality data is collected either through a routine surveillance system, survey or clinical research it is important that this data is analysed and presented in a way that can lead to improved patient management or public health action. A table is simply a standard way of arranging a set of data into rows and columns and a good starting point for preparing powerful visual displays of data, such as graphs and charts, where some of the detail of the data may be losc lf the amount of data is small and relationships are simple, a table may be all that is needed. Therefore, in preparing tables, it is important to keep in mind thattheir primary purpose isto"communicate" information about the data and that, almost any quantitative information can be organised into tables.

The last few months have witnessed a massive cholera epidemic in KwaZulu-Natal province. Also, cholera has recently been reported in Mpumalanga North-West, Gauteng and Western Cape provinces. In the Northern province, an unusual number of patients with diarrhoeal disease have been reported, and at least one death confirmed as due to cholera at autopsy.

Human rabies is endemic throughout South Africa and every year a number of deaths occur, mainly in children largely due to bites from infected dogs, coupled to incorrect management after the exposure.The encephalomyelitis that follows central nervous system invasion bythe rabies lyssavirus is invariably fatal. However modern vaccines and immunoglobulin registered for use in South Africa are safe and very effective in preventing rabies when administered correctly before and after exposure. Unfortunately the prohibitive cost of rabies vaccine does not allow for prophylactic routine immunisation of all children or indeed for the immunisation of all animal bke victims in South Africa.This article reviews current best practice in determining which persons should receive pre-exposure vaccination and post-exposure treatment. lt updates and expands the clinical guidelines for rabies management prepared by the South Africa Department of Health, briefly discussing specific principles of management. In addition, the confirmation of diagnosis and approach to patient care are described.

ldentifying the exposure or agent responsible for causing a particular disease, is often a prerequisite to developing effective prevention strategies, and improving patient management. However controversy may accompany the detection or refutation of a causal link. A good example was the debate in South Africa about the cause of acquired immunodeficiency syndrome (AIDS).

South Africa's wildlife reserves are a major tourist attraction and source of employment. The reserves have many of Africa's large wild mammals; however, attacks by these animals pose a risk not only to tourists but also to workers on the reserves. Commercial press records covering all South African newspapers were reviewed for a 10-year period to identify all reported deaths and injuries to workers on wildlife reserves resulting from encounters with wild mammals. During the period, six workers were reported killed and 14 workers were reported injured in such encounters. Although better reporting mechanisms are needed, attacks on workers by wild mammals in South African wildlife reserves appear to be rare. None of the cases reviewed here can be considered an unnatural, unprovoked attack. It is essential that all workers on wildlife reserves have training on how to avoid attacks and how to respond if an attack occurs.

Objective: To assess the repellency effect of three local plants; fever tea (Lippia javanica), rose geranium (Pelargonium reniforme) and lemon grass (Cymbopogon excavatus) against laboratory reared Anopheles arabiensis mosquitoes. Design: A laboratory experimental study. Setting: Mpumalanga Province, South Africa. Subjects: Three adult male volunteers. Main Outcome Measures: Affordable alternatives to synthetic repellents against biting of Anopheles arabiensis mosquitoes. Results: All three alcohol plant extracts provided significantly more protection (p = 0.012) than alcohol control. The alcohol plant extract of L. javanica provided 76.7% protection against An. arabiensis after a four hour period, and C. excavatus and P. reniforme provided 66.7% and 63.3% protection for three hours, respectively. At five hours post application only L. javanica alcohol extract provided appreciable protection (59.3%) against An. arabiensis. Conclusion: The results of this study indicate that L. javanica, P. reniforme and C. excavatus protect against An. arabiensis mosquito bites with the repellent effect of L. javanica lasting significantly longer than that of the other two plants.

Objectives. To determine routine measles coverage at district level and to explore reasons for immunisation failure in Mpumalanga Province, South Africa. Design. An adaptation of the World Health Organisation (WHO) Expanded Programme on Immunisation (EPI) cluster sampling method was used to make a random selection of 30 clusters in each of 21 health districts, 630 clusters in total. Seven individuals from the age group 12-23 months were randomly selected from each cluster and immunisation status and source were transcribed from their child health records. Where no immunisations were administered, reasons provided by parents or guardians were recorded. Setting. Mpumalanga Province, South Africa. Results. The weighted valid population coverage with measles vaccine for children aged 12-23 months in Mpumalanga Province was 71.1% (95% confidence interval 64.9-78.5%); this was the lowest of all EPI antigens. There was marked heterogeneity in measles coverage across the province, with a coefficient of variation of 22.2%. Districts with the lowest coverage shared borders with neighbouring provinces. District measles coverage was highly positively correlated with diphtheria, pertussis and tetanus (DPT3) coverage (r = 0.960, P = 0.000). There was a strong negative correlation between ranked measles campaign coverage and routine measles immunisation coverage. Obstacles to immunisation accounted for nearly half (49%) of all reasons for immunisation failure,while lack of information and lack of motivation accounted for 30% and 22%, respectively. Conclusions. Survey results highlight the need for supplementary immunisation, including non-selective campaigns, if Mpumalanga is to achieve the South African goal of measles elimination by 2002. The value of determining district resolution coverage in order to identify areas with low measles coverage requiring supplementary intervention was also demonstrated. A strong negative correlation between routine and campaign coverage deserves further study in other settings.

Objective. To assess community knowledge and perceptions about malaria and its control in a rural setting. Design. Descriptive cross-sectional survey. Setting. Tonga district with a population of 116,418, seasonal malaria with an annual incidence of 3200 cases. Subjects. Female heads of 299 randomly selected households. Methodology. A total of 299 households were selected from a random sample of 30 clusters. Community knowledge and perceptions about malaria and its control were assessed by interviews with the female head of each of the 299 selected households. Results. Respondents ranked malaria as the third most serious health problem facing the community after TB and AIDS. Seventy-two per cent (214/299) of respondents reported that they knew what malaria disease was and of these, 92.1% (197/214) mentioned mosquito bites as the cause of malaria. The respondents' understanding of the causal role of mosquitoes in malaria was significantly related to their knowledge about disease symptoms (P < 0.001). Reported community compliance with the malaria control programme (MCP) was satisfactory; 86.6% (259/299) of respondents reported that their homes had been sprayed during the past 2 years but 10.0% (30/299) did not know why homes were sprayed. Hospitals or clinics were the facilities where respondents most commonly sought treatment for fever; 66.9% (200/299) reported that they would seek treatment immediately after the onset of high fever. Specific practices such as replastering or washing of inside walls compromised the effectiveness of the MCP. Personal preventive measures were sometimes used against malaria (50.8%, 152/299) and use was positively associated with education level (P = 0.001). Respondents expressed their desire for more information about malaria and their willingness to contribute to the control of malaria in their community. Conclusion. The survey collected information which was directly relevant to the development of health education messages to increase community awareness of the problem of malaria, to emphasise the importance of early diagnosis and prompt treatment of malaria, to improve community understanding of the function of indoor residual spraying, and to enlighten the population of the role of mosquitoes in malaria transmission and the availability and benefits of personal protection measures against mosquito bites.

Three commercial repellents marketed in South Africa: Bio-Skincare(TM) (BSC, oils of coconut, jojoba, rapeseed and vitamin E), Mosiguard(TM) towelletes with 0.574g quwenling (p-menthane-3,8-diol, PMD) and the standard deet (15% diethyl-3-methylbenzamide, Tabard(TM) lotion), were compared against a laboratory colony of the mosquito Anopheles arabiensis Patton (Diptera: Culicidae), the predominant malaria vector in South Africa. Human forearms were treated with 1.2g BSC, 0.8g PMD towelette or 0.5g deet and exposed to 200 hungry An. arabiensis females for 1 min, at intervals of 1-6h post-treatment. Tests were conducted by three adult male volunteers (aged 30-45 years, crossover controlled test design for 3 consecutive days), using their left arm for treatment and right arm for untreated control. Biting rates averaged 39-52 bites/min on untreated arms, All three repellents provided complete protection against An. arabiensis for up to 3-4h post-application; deet and PMD gave 90-100% protection up to 5-6h, but BSC declined to only 52% protection 6h post-treatment. These results are interpreted to show that all three repellent products give satisfactory levels of personal protection against An. arabiensis for 4-5h, justifying further evaluation in the field.

Monthly collections of the Anopheles gambiae complex mosquitoes were made on human bait at seven fixed sites in the Lowveld Region of Mpumalanga Province, South Africa, between August 1997 and May 1998 to contribute to the evaluation and planning of the malaria vector control programme. Members of the An. gambiae complex were distinguished from other anopheline species using morphological keys and were subsequently specifically identified by polymerase chain reaction (PCR). A total of 5084 anophelines were collected during the survey, of which 2837 (55.8 %) were Anopheles coustani Laveran, 1418 (27.9 %) were members of the Anopheles funestus group, 435 (8.6 %) were members of the An. gambiae complex, 264 (5.2 %) were Anopheles pretoriensis Theobald, and 130 (2.6 %) comprised nine other anopheline species. From a total of 425 PCR identifications of adult females of the An. gambiae complex, 238 (56.0 %) were Anopheles merus Donitz, 129 (30.4 %) Anopheles quadrianmulatus Theobald and 58 (13.6 %) were Anopheles arabiensis Patton. No circumsporozoite antigen for Plasmodium falciparum was detected in any of the female An. gambiae complex mosquitoes. Monthly A n. gambiae s.l. captures were significantly correlated with rainfall but there was no correlation between mosquito captures and monthly malaria notifications. Malaria notifications were, however, strongly associated with mean dally temperatures. The peak in malaria incidence paralleled the peak in rainfall with a time lag of 2-3 months. This study provides updated information on the distribution of the An. gambiae complex in Mpumalanga Province's Lowveld Region, notably the incidence of mosquitoes biting humans outside sprayed houses between 18:00 and 22:00. The study also provides the first documented evidence of large numbers of An. merus feeding on humans in Mpumalanga. Further analysis of rainfall and temperature patterns may facilitate the prediction of malaria epidemics with sufficient lead-time to enable the Provincial Malaria Control Programme to launch pre-emptive control measures.

Objectives To investigate primary care clinicians' knowledge of tuberculosis (TB) management and control. Methods: A cross-sectional survey of primary care clinicians in public service, attending the TB symposium organised for the 1999 World TB Day in Mpumalanga Province,South Africa. One hundred and sixty-eight primary clinicians completed the questionnaire. Respondents included 36 doctors (21%),94 nurses (58%) and 34 (21%) allied health professionals. The response rate was 100%. Results The mean questionnaire score was 58% (range: 0-97%) but there was profound heterogeneity in answers to specific questions. Certain deficiencies found could seriously compromise TB management, for example the finding that only 55% of respondents knew the correct duration of continuation phase therapy for new pulmonary TB patients. Doctors performed better on the questionnaire, with 64% (23/ 36) scoring greater than 75% compared to 20% (20/98) of nurse practitioners, but doctors were, weaker in questions relating to TB control. Nurse practitioners who had attended TB training programmes scored considerably better than their colleagues, with 47% (14/30) scoring greater than 75% compared to 8% (5/64) of their colleagues (Xt= 19.12; p=0.000;. Respondents demonstrated limited knowledge of managing childhood TB. Only 17% (28/ {pipe} 68) could provide the rationale for BCG immunisation, 33% (55/168) provided the indication for tuberculin skin testing and 21% (35/ 168) named the correct prophylactic TB therapy for children under two years. Conclusions Nurse clinicians in Mpumalanga Province who had attended TB training programs demonstrated superior knowledge on TB management and control com-pared to their colleagues who had received no training. Primary care doctors appear to be an under-utilised resource in the TB Control Program in Mpumalanga Province and require orientation on control program priorities. In general,the knowledge of primary care clinicians on managing TB in children is inadequate and must become a focus for future training.

In our previous article in this series, we considered categorical data and noted that this form of data was usually summarised using proportions. The other major data-type is quantitative data. Quantitative data may either be counted as whole numbers (discrete data), e.g. the number of cases of meningococcal meningitis in an outbreak on a mine, or be measured using a continuous scale, e.g. temperature measurement of a patient with brucellosis.

Quantitative data is traditionally summarised by two measures: A measure of the centre (average) of a data set and one of spread around this central point. In the previous article we noted that there are four useful measures for depicting the centre of a set of data namely the "arithmetic mean", "median", "mode" and "geometric mean". For the spread of a data set around the central point,there are three measures that are commonly used viz. the range, inter-quartile range and standard deviation.

Bacterial meningitis is one of a select group of febrile illnesses that may rapidly progress unless suspected early by the family practitioner. Unless appropriate therapy is initiated without delay, the outcome is often fatal. This article provides the family practitioner with an overview of current best practice when treating bacterial meningitis. Emphasis is placed on a high index of suspicion, particularly in certain patient groups like children where unusual atypical presentations are common. Empirical treatment options by age group for immediate therapy is discussed and the useful array of diagnostic modalities available is cataloged. The issue of chemoprophylaxis for close contacts of meningococcal disease patients and the importance of immediate notification are succinctly discussed. On a prevention note, the appropriateness of providing vaccination to travelers is considered.

Meticulous preparation and an intimate knowledge of available equipment and techniques, characterize most successful expeditions or adventures, whether they be the treacherous climb to the summit of Kilimanjaro, the arduous swim across the English Channel or nerve-wracking analysis of one's first data-set. Being confronted by a large number of measurements can be intimidating and attempts at analysis an utter waste of time unless a systematic approach is adopted. An important first exploratory step before launching into the production of florid graphics, is to convert data into a simple presentation form that allows insightful "eye-balling". We have already introduced the concept of discrete data with its distinct categories,e.g. male and female. These categories are useful for constructing tables and we will discuss the immense value of well-constructed tables for analysing and communicating data in the next article in this series.

The results of a confidential inquiry into mortality attributed to malaria in South Africa's Mpumalanga Province are being used to guide the design of strategies for improving the management of cases and reducing the probability of deaths from the disease.

Objectives. To determine the use of antimalarial prophylaxis and the relative frequency of adverse events with different regimens in visitors to the Kruger National Park. Design. Retrospective postal survey of a cohort of 7397 visitors during April 1996. Telephonic interviews were conducted with all respondents who reported neuropsychiatric adverse events necessitating medical attention, and their medical caregivers. Results. The most commonly used regimens were chloroquine and proguanil in combination (C and P) (35.6%) and mefloquine (18.4%). However, non-recommended regimens were also used by travellers to this chloroquine-resistant area, including chloroquine alone (15.7%). Adverse events were reported by 23.8% of travellers and were more common in the C and P group than the mefloquine group (28.9% v. 25.0%, P = 0.0100). Gastro-intestinal side-effects were significantly more common in the C and P group (nausea (P = 0.0170), diarrhoea (P = 0.0008), mouth ulcers (P = 0.0000)), while neuropsychiatric side-effects were more common in the mefloquine group (depression (P = 0.0000), light-headedness (P = 0.0009), anxiety (P = 0.0060)). Only 30% of travellers reported using antimalarial drugs both regularly as prescribed and for 4 weeks after leaving the malaria area. The most commonly reported reason for changing prophylaxis was advice from a physician or pharmacist (41.9%). Conclusions. Health professionals providing medical advice to prospective travellers to malarious areas must tailor recommendations based on the balance between malaria risk in a specific geographical area and the benefits and tolerance of protective measures. Mosquito-avoidance measures should always be advocated, but counselling on antimalarial prophylaxis will be guided by the malaria/prophylaxis (serious adverse events) risk ratio. Where drug measures are indicated, the importance of their correct use should be emphasised.

SETTING: The Kruger National Park (KNP), Mpumalanga Province, South Africa. OBJECTIVE: The prevalence of tuberculosis caused by Mycobacterium bovis exceeds 70% in African buffalo in the southern region of the KNP. Inter-species transmission (lion, cheetah, baboon, antelope) has also been confirmed. Regular culling of emaciated buffalo and processing of meat and hides constitute routine control policy. Following extensive media coverage of the problem, public health concerns about the transmission of M. bovis to humans, including visitors to the KNP, prompted this investigation. DESIGN: The study was designed to determine the prevalence of infection and/or active disease due to M. bovis among KNP employees selected from three defined risk groups based on occupation category. RESULTS: Of 206 persons screened for active disease by sputum bacteriology, two persons with disease due to M. tuberculosis were identified. No isolate of M. bovis was found. Differential skin testing using three antigens failed to show any degree of M. bovis infection risk, even among high risk occupations. Reasons for these results are discussed. CONCLUSIONS: Bovine tuberculosis was not indicated as an occupational zoonosis in the KNP, nor was aerosol transmission implicated as a mechanism for human infection. Concerns about the public health implications of tuberculosis in buffalo in the KNP have therefore not been validated.

Background: The risk of malaria to visitors to South Africa's nature reserves is unknown. Current recommendations for travelers are based on malaria incidence rates in local communities. These rates may well overestimate travelers' malaria risk and lead to unnecessary use of antimalarial prophylaxis with associated drug-related adverse events. This study investigated the incidence of malaria in visitors to South Africa's Kruger National Park (KNP). Methods: Postal questionnaires were sent to the cohort of visitors staying in the KNP during April 1996, 6 to 8 weeks after they returned to their homes. Nonrespondents received duplicate questionnaires 8 weeks later. Responses from 3267 groups, representing 11,107 visitors (56.8%) allowed determination of the malaria attack rate in this group of travelers and assessment of associations between malaria risk and a number of factors, including type of accommodation used during the visit; duration of stay; use of chemoprophylaxis; and use of personal protection measures. All travelers indicating that they had suffered an episode of malaria following their visit were telephonically contacted and their health providers traced to determine the basis of diagnosis and clinical outcome. Results: One clinically suspected and four confirmed cases of Plasmodium falciparum malaria among the visitors suggest a low attack rate of 4.5 cases per 10,000 visitors during April, the highest risk month for malaria in South Africa. No association was found between malaria risk and accommodation type, duration of stay, use and type of chemoprophylaxis, and use and number of personal protection measures. Conclusions: These findings confirm the importance of careful assessment of local malaria risk before individualized advice is provided to travelers.