The Eighteenth African Health Sciences Congress : Dissemination of Research Results for Utilisation

The African Health Sciences Congress for 1997 will be held in Cape Town; South Africa; from 14 to 18 April. This congress has been an annual event where scientists from across the world meet to present research results and to discuss meaningful approaches to solving some of the world's pressing health problems. The congress which is under the aegis of the African Forum for Health Sciences (AFHES); focusses special attention on ways of finding solutions for problems that afflict the African. The AFHES aims to accentuate; through these meetings; practical approaches that can be used by African governments to tackle health-related matters in order to improve the socio-economic status of the people on the African continent. The common health-related matters that one would be expected to be covered at such a congress are the six major tropical diseases identified by the World Health Organisation (WHO); namely malaria; filariasis; schistosomiasis; leishmaniasis; trypanosomiasis and leprosy. But now; there are other health-related problems on the continent that must be dealt with in order to ensure quality of life. Among them are the new and re-emerging diseases like the haemorrhagic fevers (Ebola and Marbug) and yellowfever; the sexually-transmitted diseases including HIV/AIDS; acute respiratory infections and reproductive health. Then there are the less often mentioned health-related problems currently afflicting the African continent that are not given so much attention as the others. These include sanitation; famine and drought; and malnutrition which arise from political upheavals leading to refugees. The consequences of these socio-economic difficulties further exacerbate the prevalence of the existing tropical and other diseases. Scientists working in Africa should play leading roles in tackling the many health problems that afflict the peoples of Africa. They are well placed to collect direct information on these health issues and to provide practical and meaningful strategies for their solution. The WHO Africa Region has taken a meaningful step towards finding mechanisms of eliminating female mutilation in Africa; and this is highlighted in the Newsdesk pages of this issue of the Journal. This; it is hoped; will be achieved through the use of the African traditional foundation and wisdom. Similarly; the African traditional culture of health should provide the basis for utilising the wisdom of the traditional healers and traditional midwives for dealing with primary health care matters on the African continent. The Journal congratulates all the scientists working in Africa; be they Africans or non-Africans; and those outside Africa; who work tirelessly to solve problems that will pave the way for an acceptable quality of life for the world's peoples. It is earnestly hoped that the scientists in Cape Town during the 18th African Health Sciences Congress will deliberate; discuss and dedicate themselves to solving Africa's pressing health problems. The Journal also acknowledges with gratitude; the organisers of this congress; namely the South African Medical Research Council; the Kenya Medical Research Institute and the Epidemiological Society of Southern Africa (ESSA); which; under the auspices of the African Forum for Health Sciences; have made it possible to hold the Congress in cape Town this year

Screening of metal ion chelators against Leishmania donovani-infected Syrian hamsters

Leishmania donovani-infected Syrian hamsters were treated intraperitoneally with 0.23 mmoles/kg/day of EDTA; EGTA; HEEDTA and 100 mg/kg/day of Pentostam R. The control group received 0.1 ml of phosphate buffered saline. After 30 days of treatment; the animals were sacrificed. Of the Pentostam-treated animals; 5 out 6 had negative spleen cultures; while all the chelator and PBS-treated ones yielded parasites. While all the Pentostam-treated hamsters yielded had negative bone marrow cultures; only 1 out of 6 HEEDTA-treated hamsters yielded parasites. Spleen; liver and bone marrow parasite-loads calculated from chelator-treated animals were consistently significantly higher than for Pentostam-treated animals. These results suggest that although metal ion chelators have some antileishmanial potential; their in vivo activity against L. donovani is low compared to Pentostam

Comparison of Giemsa and acridine orange stains for the diagnosis of Leishmania donovani in biopsies of infected hamsters

Identical impression smears of spleen; liver and bone marrow biopsy materials from Leishmania donovani-infected hamsters were stained using either acridine orange or Giemsa. Spleen parasite-loads calculated from the two stains for identical biopsy material were significantly different from each other. However; liver and bone marrow parasite-loads calculated from either Giemsa-stained or acridine orange-stained biopsies were not significantly different from each other. This study has shown that acridine orange; which is a quick and simple technique; has great potential in the diagnosis of kala-azar when liver and bone marrow biopsies are used

Determination of the optimal EDTA and Pentostam concentration in the treatment of Leishmania donovani-infected laboratory animal rodent models

The objective of this study was to undertake a dose response study to determine the optimal Pentostam and Ethylenediamine tetraacetic acid (EDTA) dose that could be used in the treatment of leishmania-infected golden hamsters or BALB/c mice for a period of 30 days. This pilot experiment was done using only one chelator; EDTA and the toxicity results obtained from this experiment formed the basis for the selection of a suitable chelator dose of this class for the future treatment of leishmania-infected laboratory animal rodent models. It is concluded that Pentostam concentrations beyond 600 mg/kg are highly toxic to mice and therefore unsuitable for use. Although Pentostam have been used to treat leishmania-infected BALB/c mice; this study has shown that a concentration of 100 mg/KG/day is the most suitable dose for use in the treatment of rodent animal models

Screening of metal ion chelators against Leishmania donovani-infected BALB/c mice

Previous in vitro experiments by Mbati et al. have shown that Ethylenediamine tetraacic acid (EDTA) and Ethyleneglycol-bis (B-aminoethyl ether) N;N;N1;N1; tetraacetic acid (EGTA) substantially reduce parasite burdens of leishmania donovani in either cell free media or when engulfed in mouse peritoneal macrophages. The objective of this study was to compare the activity of the same chelators against Leishmania donovani in BALB/c mice infected with a much lower parasite inoculum

Identification of schistosome-infected snails by detecting schistosomal antigens and DNA sequences

Cercarial shedding tests do not provide species identification of the shistosomes concerned and cannot detect prepatent schistosomal infections. We have demonstrated that both immunodetection by ELISA of schistosomal antigens in snail hemophlymph, and dot hybridization of snail extracts by DNA probe representing highly repeated sequences, proved suitable for detecting infected snails during prepatnecy as well as patency. A group-specific monoclonal antibody was found to be suitable for detecting Schistosoma mansoni infection in Biomphalaria sp., but not for positive identification of S. haematobium in Blulinus sp. Comparative evaluation of the diagnostic qualities, and technical aspects and cost of these tests, point to the superiority of the immunodetection approach for large scale detection of snails prepatently infected with S. mansoni. This approach is potentially useful for providing extended information on schistosome-snail epidemiology that may facilitate rapid evaluation of the danger of post-control reinfection, and help make decisions on the time and place of supplementary control measures. In this context the potential usefulness of the immunodetection or DNA probing approach for facilitating catalytic model representation of schistosome-snail epidemiology warrants further evaluation. Specific identification of S. haematobium in Bulinus by either of these approaches may be possible depending on the development of suitable antibodies or DNA probes

Evaluation of the optimal inoculation of leishmania major culture-derived stationary phase promastigotes required to assess protective immune status in the vervet monkey model

"Vervet monkeys have been shown to be resistant to a homologous challenge of Leishmania major after an active infection followed by self cure responses. Confirmation of the protective immune status of such animals was demonstrated by exposing a group of 4 monkeys to multiple infected sandfly challenge. Two animals revealed small transient nodule formation while in the remaining two; no signs or symptoms were obvserved. In order to ascertain the level of promastigote challenge which was equivalent to such a ""natural"" fly challenge; 3 additional groups of immune vervet monkeys were challenged with 1x103; 1x104 and 105 stationary phase culture promastigotes in the presence of salivary gl and lysates. In all groups; there was no lesion development whatsoever. A second challenge of 1x106; 1x107 and 4x107 in these same animal groups; revealed self healing nodules in the group inoculated with 1x106 promastigotes whilst in the remaining 2 groups challeged at the higher levels; there was nodule formation which progressed to ulceration. A challenge dose of 1x105 culture promastigotes was thus considered to be optimal since this level of challenge in naive animals was demonstrated to result in ulcer formation when inoculated with salivary gland lysates."