Phosphorus budget in the low-income, peri-urban area of Kibera in Nairobi (Kenya).

Kibera, located in Nairobi, Kenya is one of the largest (235,000 inhabitants) low-income areas in East Africa. Surface waters in Kibera show high pollution levels with respect to SRP (soluble reactive phosphorus; range: 2-10 mg P/L), coming from the uncontrolled wastewater discharges in the area. The different P production and consumption values in Kibera were estimated using interviews (155 interviewed) as well as detailed P house-keeping for five representative families. The results show that highest P consumption comes from food, in particular cereals. Highest P production came from urine (55% of the total) and faeces (31%), with relatively lower contributions from grey water and solid wastes. The overall P budget in Kibera amounted to around 9 x 10(3) kg P/month. This is equivalent to 0.47 g P/person yr, both for P production and consumption, with a relative error of 20%. Comparing with the estimated P outflows via the Kibera surface waters, around 65% of the P produced in Kibera will leave the area. In future ECOSAN techniques such as urine separation could well be applied for efficient recycling of these waste sources.

CD4T lymphocyte subsets and disease manifestation in children with and without HIV born to HIV-1 infected mothers.

OBJECTIVE: To understand the natural history of HIV-1 infection in children in terms of evolution of childhood clinical manifestations versus the immune status, we prospectively studied children with and without maternally transmitted HIV-1 infection born to mothers infected with HIV-1 for two years between March 1998 and March 2000. DESIGN: A prospective cohort study. SETTING: An institutional children's home. SUBJECTS: Fifty nine children (26 males and 33 females) with and without maternally transmitted HIV-1 infection born to mothers infected with HIV-1 and adopted in institutional children home. METHODS: HIV-1 status of children under nine months was confirmed by polymerase chain reaction(PCR). ELISA for HIV-1 antibody in serum/plasma was used to confirm HIV-infection status for children aged < or = 18 months. Children were visited every three months between March and June 2000. At every visit blood was collected for total white cell count, haemoglobin and CD4+ and CD8+ T cell counts. The institutional doctor routinely examined children and treated all ailments. Clinical data were recorded. MEASURES: HIV-DNA, anti-HIV antibodies, total white blood count, total T cell counts, CD4 and CD8 T cell subset counts, frequency of childhood manifestations of infection. RESULTS: The children were aged between 4.5 and 13 years. The baseline haematological and immunological profiles (mean, mode) were: HIV-1 sero-converters (WBC 7151,7150; HB 11.6, 12.0; CD4+ 686, 795; CD8+ 2168, 1507) and HIV-1 de-seroconverters (mean, mode) were: (WBC 8386, 7150; HB 11.7, 12.8; CD4+ 735, 795; CD8+ 2168, 1507). The commonest causes of illnesses among the HIV-1 children were URTI (85.3%), TB(56.1 %), pneumonia (56.2%), tonsillitis (34.1%), parotiditis (28%) and acute otitis media (25%). The distribution of clinical manifestations was similar between the two categories of children, except URTI, whose prevalence was significantly increased among HIV-1 infected children (p-value=0.006). Among the HIV-1 infected children, only TB, parotiditis, and acute otitis media (AOM) were significantly associated with decreased CD4+ T cell count (p<0.05) resulting from HIV infection. CONCLUSIONS: HIV infection in children predisposes them to common childhood infections that can be used as markers of immune decline. TB, AOM, URTI may be early indicators of suspicion that would enable selective screening for HIV infection in children.

Maternal immune responses and risk of infant infection with HIV-1 after a short course Zidovudine in a cohort of HIV-1 infected pregnant women in rural Kenya.

OBJECTIVE: To investigate the effects of short-course nucleoside reverse transcriptase inhibitor (Zidovudine, ZDW/AZT) on maternal immune responses and risk of infant infection with HIV-1 among rural-based mothers in western Kenya. DESIGN: A prospective cohort study involving HIV-1 seropositive pregnant mothers and their infants. SUBJECTS: One hundred and seven HIV-1 seropositive asymptomatic pregnant women and their infants. METHODS: After informed consent, the women were enrolled at gestation age between 16-24 weeks. For cultural and economic reasons, all mothers were allowed to breast feed their infants. Short-course antepartum regime of AZT was administered to all mothers starting at 36 weeks gestation until start of labour. Maternal absolute CD4+ T cell subset assays were performed before 3rd trimester (about 36 weeks gestation) and after a 4-week therapy of AZT (at least one month post-nuptially). Infant HIV-1 status was determined by HIV-1 DNA polymerase chain reaction (PCR) on samples sequentially taken at 1, 2, 3, 4, 6 and 9 months and confirmed by serology at 18 months of age. INTERVENTIONS: Antepartum short-course orally administered AZT: 300mg twice-daily starting at 36 weeks gestation until start of labour, 300mg at labour onset and 300mg every three hours during labour until delivery. MAIN OUTCOME MEASURES: Maternal CD4+ T cell counts before and after AZT treatment. Determination of infant HIV-1 infection status. RESULTS: Among 107 women sampled, only 59 received full dose of AZT and thus qualified for present analysis. Of these, 12 infected their children with HIV, while 47 did not. Comparison of CD4+ T cells before and after AZT treatment scored a significant rise in all mothers (P = 0.01). This increase in CD4+ T cells was not significant among mothers who infected their infants with HIV-1 (P = 0.474). However, a significant rise in CD4+ T cells following AZT therapy was observed only in mothers who did not transmit HIV-1 to their infants (P=0.014). CONCLUSION: These data suggest that a rise in the CD4+ T cell counts following short AZT regimen, now widely in use in resource-weak countries, may be evidence of the active suppression of the replication of HIV. However, further studies to examine the multi-factorial effect of CD4+ lymphocytes and pregnancy on MTCT of HIV need to be carried out to help fully explain the effect of AZT on immune response and whether the CD4+T cell count can be used as a true test of immunological normalisation during antiretroviral therapy.

Transmission blocking vaccine studies in leishmaniasis: II. Effect of immunisation using Leishmania major derived 63 kilodalton glycoprotein, lipophosphoglycan and whole parasite antigens on the course of L. major infection in BALB/c mice.

BACKGROUND: Safe, effective and inexpensive vaccines may be the most practical tool for control of any form of leishmaniasis. Leishmaniasis produces a state of pre-immunition which is the underlying mechanism for prolonged immunity to re-infection. Low doses of parasites has been shown to be able to induce protection in mice. It is not known, however, how immune sera from a susceptible host immunised with Leishmania-derived antigens when taken in by the sandfly affects the development and the subsequent transmission of the parasite to naive hosts. OBJECTIVE: To monitor the course of disease in BALB/c mice following challenge using L. major infected P. duboscqi which had previously fed on immunised mice. METHODS: BALB/c mice were immunised adequately with Leishmania major-derived antigens namely, crude whole parasite (WPA), recombinant 63 kilodalton glycoprotein (rgp63), lipophosphoglycan (LPG) and a cocktail composed of rgp63 plus LPG antigens. Laboratory reared Phlebotomus duboscqi sandflies, the natural vector for L. major were later allowed to feed on immunised animals, interrupted and allowed to continue feeding on infected animals for an equal amount of time until they became fully engorged. The sandflies were maintained on apples as a carbohydrate source in an insectary maintained at a temperature of 25 degrees C and 80% relative humidity. On the seventh day these sandflies were used to infect naive BALB/c mice and the course of infection followed for a period of at least three months. RESULTS: Mice infected using sandflies which had previously fed on WPA or rgp63-immunized mice showed disease exacerbation as the infection progressed, whereas those infected using sandflies which had previously fed on LPG-immunised mice had the least lesion sizes compared to control mice infected using sandflies which had fed on saline immunised mice (p < 0.05). CONCLUSIONS: Results from this study indicate that the course of L. major infection in BALB/c mice was dependent on the infective dose of parasites transmitted by the sandflies. Results from this study suggests that sub-infective doses of the parasite from sandflies previously fed on animals immunised with Leishmania-derived antigens needs to be evaluated for their potential in vaccine development against Leishmania infections.

Transmission blocking vaccine studies in leishmaniasis: I. Lipophosphoglycan is a promising transmission blocking vaccine molecule against cutaneous leishmaniasis.

BACKGROUND: New strategies for control of leishmaniasis is needed as chemotherapy using antimonial drugs is prolonged, expensive, associated with side effects and relapses. Vector control has limitations and a vaccine which may be the best approach is not available. OBJECTIVES: To assess the level of inhibition of promastigote development and gut morphology in infected Phlebotomus duboscqi sandflies fed on different groups of BALB/c mice immunised with rgp63, lipophosglycan (LPG) or their cocktail and whole parasite antigens prepared from L. major culture-derived promastigotes. METHODS: BALB/c mice were immunised adequately with Leishmania major-derived antigens namely, crude whole parasite (WPA), recombinant 63 kilodalton glycoprotein (rgp63), LPG and a cocktail composed of rgp63 plus LPG antigens. Laboratory reared Phlebotomus duboscqi sandflies, the natural vector for L. major were later allowed to feed on immunised animals, interrupted and allowed to continue feeding on infected animals for an equal amount of time until they became fully engorged. The sandflies were maintained on apples as a carbohydrate source in an insectary maintained at a temperature of 25 degrees C and 80% relative humidity. Some of the sandflies were dissected on days 2, 4 and 6 after feeding and observed using the light and the transmission electron microscopy for any changes in their gut morphology. The remaining sandflies were all dissected on the sixth day post-feeding and examined for procyclics, nectomonads, haptomonads and metacyclic promastigote forms of Leishmania. RESULTS: Sandflies which had previously fed on WPA, LPG plus rgp63 cocktail and LPG-immunised mice showed the lowest infection rates compared to control sandflies fed on saline immunised mice (p < 0.05). A significant number of procyclic promastigotes, the first developmental form of the parasite in culture as well as in the sandfly was observed in sandflies which fed on LPG-immunised mice (p < 0.05). The dominant parasite form in sandflies which fed on rgp63 or LPG-immunised mice was the nectomonad form but very few of the infective metacyclic forms (p < 0.05). Control sandflies fed on saline immunised or infected mice alone displayed a normal pattern of parasite development up to the metacyclic stage. Studies showed that two possible mechanisms through which immune sera from immunised mice may cause inhibition of parasite development is by exflagellation of nectomonad forms and degeneration of the sandfly midgut epithelium as revealed by light and electron microscopy studies respectively. CONCLUSIONS: This study has shown that immune-mediated transmission blocking may be applied to Leishmania infections. Based on observation of the procyclic promastigotes, the dominance of the nectomonad forms, low infectivity rates in sandflies fed on LPG-immunised mice, we concluded that LPG stands out to be a promising transmission blocking vaccine candidate in leishmaniasis.

The place of science in a continent at the crossroads.

I have mentioned it before and I want to repeat it now, that we in Africa share a common history, heritage and basic problems of development. We, therefore, have an inescapable responsibility of pooling our talents and resources in shaping our common destiny. In fulfillment of its mission, AFHES, through its organized con notgresses and this Journal, is an invaluable vessel for enabling us to promote better health for the peoples of this continent. Africa is a continent endowed with great potential that, for one reason or an notother, has been ignored or misused, resulting in the current crisis now enveloping the continent. There is the escalating debt burden, falling agricultural productivity and the ever-increasing population. Efforts to improve the situation are hampered by adverse factors such as malnutrition, HTV/AIDS, malaria and other causes of ill health; wars, poor environmental management and the ever-worrisome problem of refugees. At the sunrise of the 21st Century, we must wake up and reverse the current trend by focusing our resources on priority areas of development. The fight for freedom from the yoke of colonialism and the traumatic experience of apartheid has been won. In some African countries, however, the winning of the fight for freedom has opened up a new fight, a fight that is more fierce and bloody than that which set us free. These include civil strife and internecine wars giving rise to a new black Diaspora, which is far greater than the one experienced during the period of slavery and slave trade. People supposed to build these nations have either been killed or forced into exile. Those intellectually endowed have sought refuge in safer and economically developed countries and, by the same process, also weaken the al notready weak economies of their mother countries. They have, therefore, helped to strengthen the already strong economies of the developed nations. This is indeed, a sad situation that poses a formidable challenge to the future well being of the conti notnent. Civil strife has resulted in the increased numbers of displaced persons and has caused a big setback in the fight against diseases and causes of ill health. In addition, there are new challenges created by emergence of new infections, re-emergence of diseases that had been put under control; and the changing epidemiological patterns and manifestations of existing diseases. Since disease and ill health know no bound notary, we must all be prepared to find solutions to diseases and causes of ill health that continuously haunt this continent. As health experts, we are concerned. We should not be responding to health emergencies occasioned by civil strife. We need peace as it will guarantee not only freedom and personal security, but it will also guarantee our future and the future of those to come after us. We are well aware that as is the case with developed nations, the development of our continent rests on the utilization of research findings, which must be useful, contextual and must stand the test of time. This is our mission and our hope. Africa is at the crossroads. We must not despair or quit, lest we become irrel notevant both to ourselves and to the rest of mankind. Let African governments give science a chance. As I have said several times before and I am still saying it now, quitters never win and winners never quit. We have no alternative but to be winners!

Impact of the crayfish Procambarus clarkii on Schistosoma haematobium transmission in Kenya.

The Louisiana red swamp crayfish, Procambarus clarkii, which was introduced into east Africa in the 1950s or 1960s, has since widely dispersed. Previous work by our group has shown that P. clarkii can reduce populations of the molluscan intermediate hosts of human schistosomes through predatory and competitive interactions. Here, we investigate whether crayfish can reduce populations of Bulinus africanus and consequently, Schistosoma haematobium prevalence in school children. Children from 6 primary schools in the Machakos and Kitui Districts of Kenya were selected for study. Schools were divided into 3 experimental-control pairs. At experimental schools, crayfish were introduced into nearby aquatic habitats harboring Bulinus africanus snails and serving as S. haematobium transmission sites. Snail habitats near control schools did not receive crayfish. Six months after crayfish introduction, all infected children were treated with praziquantel. Children were then monitored quarterly for 2 years, at which time infection and reinfection rates were compared statistically between the paired schools. In one such pair, crayfish failed to establish, resulting in neither snail control nor a reduction in transmission. At the second pair of schools, the numbers of snails were decreased by the presence of crayfish, but a clear difference in infection rates in children could not be detected, primarily because drought conditions kept overall transmission rates low. At the third school pair, crayfish established well in experimental habitats, snail numbers decreased precipitously, and children at the experimental school were significantly less likely to acquire S. haematobium infections than children at the control school. Our results indicate that under certain environmental circumstances, P. clarkii exerts a significant impact on the transmission of human schistosomiasis in Kenya. Important questions remain regarding the impact of P. clarkii on Kenyan freshwater ecosystems, not the least of which is its potential to significantly influence the epidemiology of schistosomiasis in east Africa.

Diagnosis of Wuchereria bancrofti infection by the polymerase chain reaction employing patients' sputum.

A preliminary evaluation of the diagnostic potential of a polymerase chain reaction (PCR) assay using diurnally collected sputum from bancroftian filariasis patients is described. A new set of PCR primers amplifying a 254-bp-long sequence termed AccI, derived from a long dispersed repeated sequence and SspI primers previously employed for PCR-based diagnosis were employed in this study with similar results. Of the 34 sputum samples from patients, 32 (94%) were PCR positive. Of the 18 patients with low to high microfilaremia (21-1560 microfilariae/ml), 16 (88.8%) were PCR positive. Of the remaining 16 patients, 6 with very low microfilaremia (2-6 microfilariae/ml) and 10 without microfilaremia, all (100%) were PCR positive. Two PCR-positive cases among the 13 endemic normal individuals tested (15.4%) may represent cases of occult filariasis. PCR amplification was also demonstrated with one PCR-positive sputum aliquot when mixed with 14 sputum aliquots from uninfected (PCR-negative) individuals. The potential diagnostic merits of the sputum-PCR assay are discussed.

Evaluation of a standardized direct agglutination test (DAT) for the diagnosis of visceral leishmaniasis in Kenya.

A prototype test kit being developed, by the World Health Organization (WHO), for the diagnosis of visceral leishmaniasis (VL) was evaluated in the Baringo district of Rift Valley province in Kenya. The screening of approximately 10,000 individuals for the signs of VL produced 305 suspected cases. These cases and 304 controls matched for sex and age (+/- 2 years) were then tested with the kit, which is based on a direct agglutination test (DAT). The evaluation was a three-stage process. The first stage, the field screening, involved screening filter-paper samples of dried blood from the suspects and controls at a DAT titre of 1:500. The second stage, the laboratory titration, involved screening of the same individuals by testing freshly eluted filter-paper samples at 1:500 to 1:2000 dilution. In the third stage, the full-scale titration, all samples that had been positive at 1:2000 were titrated at 1:500-1:512,000. All the suspects giving DAT titres of 1:2000 or higher were considered positive for VL. This diagnosis was checked, whenever possible, by the examination of smears and/or cultures of splenic aspirates for leishmanial parasites. Those found to be parasitologically positive were put on a standard treatment regime of 20 mg sodium stibogluconate (Pentostam)/kg.day. Although 42 (13.8%) of the 305 clinical suspects investigated were DAT-positive (at 1:2000), it was only possible to take splenic aspirates from 32. Four (12.5%) of these 32 were apparently false-positives by DAT, as no parasites could be detected in their splenic aspirates. The others provided positive smears and cultures (27 cases) or a negative smear but a positive culture (one case). It was possible to re-examine two of the four serologically positive but parasitologically negative VL suspects at a 3-month follow-up: neither had a palpable spleen, one had seroconverted and the other had much lower DAT titre (1:32,000) than when investigated previously (1:128,000). All the parasitologically confirmed cases remained DAT-positive (1:2000) at this follow-up. The low cut-off titre (1:2000) and the simple procedure should make the kit suitable for use by health workers at all levels of primary-health care, including those with limited training and skills, for screening rural communities at risk of VL.

Experimental control of the schistosome-transmitting snail Biomphalaria pfeifferi by the ampullariid snail Pila ovata.

Adults of the African ampullariid snail Pila ovata were examined for their ability to control laboratory populations of the pulmonate snail Biomphalaria pfeifferi, a widespread, intermediate host of the human pathogen Schistosoma mansoni in sub-Saharan Africa. In a 6-week experiment conducted in large (100 x 60 x 60 cm) outdoor tanks containing floating macrophytes (Nymphaea caerula) and initially set up with one adult ampullariid for every three adult pulmonates, the numbers of B. pfeifferi egg masses were always about half those in similar tanks without P. ovata. Although, by week 6, the numbers of B. pfeifferi in the control tanks (without ampullariids) had increased 5-fold, from an initial mean of 30 snails/tank, there was no significant increase in the numbers of B. pfeifferi in the experimental tanks (containing ampullariids). Results of experiments conducted in indoor glass aquaria indicated that adult P. ovata rapidly attacked egg masses or neonates (< 2.5 mm shell diameter) of B. pfeifferi but had no effect on the adults. The adult ampullariids also significantly decreased cover by floating macrophytes over a 6-week period compared with that in similar but ampullariid-free aquaria. This decrease in plant cover is relevant to biological control of the schistosome vectors as macrophytes serve as food, shelter and oviposition sites for pulmonate snails. The present result indicate the ability of P. ovata to inhibit multiplication of B. pfeifferi populations, at least under laboratory conditions, both directly, through predation, and indirectly, by competition for resources. Pila ovata may therefore prove useful in the biological control of medically important, pulmonate snails.

The need for rehabilitation of lost skills in health care delivery.

During the last 40 years or so when African nations started regaining their independence from colonial rule, vigorous programmes were initiated for education and training in all sectors of national development. The leaders of these independent nations set their goals on the elimination of ignorance, poverty and disease. Thus matters of health have been a priority over these years. Health care personnel have been trained in all the relevant areas such as medicine, pharmacy, nursing, dentistry and all other allied professions. However, the maximum utilisation of the trained health care manpower has not kept pace with the rapid needs of development in these nations. This deficiency has been compounded by the rapid advancements in medical science and technology. Thus in the under-utilisation of these graduates from tertiary educational institutions, the graduate becomes professionally obsolete due to the fact that he/she has not been adequately utilized, or due to lack of continuing education, or due to some othef reasons. The medical doctor, dentist, pharmacist, nurse, clinical officer or laboratory technologist may have lost the special skills that were acquired during college education and may therefore become professionally and functionally senescent and obsolete. So there is need to habilitate those skills in order to serve efficiently in the provision of health care. I am afraid that some of the personnel did not have sufficient background education and hence would not benefit from rehabilitation programmes, let alone training in newer technologies. Similarly, I dare say that in the university faculties and departments and polytechnics that educate and train the prospective health care personnel, many of the teaching staff would also require rehabilitation of their skills that may have become obsolete. There is also need for such rehabilitation in the health research institutes in order to provide the relevant answers for the solution of national health problems. Thus as we move into the next millennium, there is dire need to rehabilitate our health personnel in the skills that have been lost in order to re-train them to be able to apply contemporary methods of health care provision. In the present state of affairs, the use of modern technological methods are essential in providing health care because these new technologies are more effective and therefore ultimately more cost-effective. Hence the need for rehabilitation of lost skills as a pre notrequisite for re-training is a priority. I call on all the health policy makers as well as those who are concerned with the improvement of health care delivery to take some critical and decisive steps to ensure that health care providers are adequately educated and properly trained. Continuing medical education as well as continuing education in other health professions should incorporate rehabilitation of lost skills as well as retraining on newer and more appropriate methods for the provision of good quality health care delivery services are important and urgent. Continuing education therefore should be a condition for continued registration and certification if we are to achieve meaningful quality health care delivery.

Antifolate drug resistance and point mutations in Plasmodium falciparum in Kenya.

Due to increased chloroquine resistance, the antifolate/sulpha drug combinations are becoming increasingly important in the chemotherapy of falciparum malaria. However, point mutations in the dihydrofolate reductase gene lead to resistance to the antifolate drugs. We therefore investigated the prevalence of the 6 reported point mutations in this gene among field isolates of Plasmodium falciparum from Kenya, to determine if the mutations correlated with resistance to pyrimethamine and the biguanides cycloguanil and chlorcycloguanil. We used a mutation-specific polymerase chain reaction technique to test for these reported mutations in 21 Kenyan isolates and 4 reference lines. We also amplified and directly sequenced the dihydrofolate reductase coding sequence from these parasites to confirm the results and test for other possible mutations. Of the reported mutations, we found S108N, which is the central mutation of pyrimethamine resistance, and mutations N51I and C59R, which modulate the levels of resistance and may confer decreases in response to cycloguanil that are folate and p-aminobenzoic acid dependent. No isolate possessed the paired point mutations S108T and A16V, or I164L and S108N, which have been associated with cycloguanil resistance in previous studies. These results provided supportive evidence for the combined use of a cycloguanil-class drug (e.g., chlorproguanil) and a sulpha drug (e.g., dapsone) against P.falciparum malaria in Kenya.

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.

Quality control of Kato slide counts for Schistosoma mansoni: a review of 12 years' experience in Kenya.

A total of 19 annual or biannual audits were performed over a 12-year period by an independent microscopist on randomized subsamples of Kato slides examined for Schistosoma mansoni eggs by Kenyan microscopists from the Division of Vector-borne Diseases (DVBD). The recounts were invariably lower than the originals owing to some deterioration of the preparations between counts, but the two were strongly correlated: significant regressions of recounts on counts taking up 80-90% of the observed variance. Observer bias differed significantly between microscopists but remained stable over time, whereas repeatability of recounts on counts dropped slightly in periods of maximum work load but did not vary systematically with time. Approximately 7% of the counts and recounts disagreed on the presence or absence of eggs, but less than a third of these were negatives that were found positive on recount. False negatives dropped to 1.3% if duplicate counts were considered. The performance of the Kenyan microscopists was remarkably high and consistent throughout the 12-year period. This form of quality control is suitable for projects where limited funds preclude full-time supervisors using more sophisticated systems.

PIP: When Kato slides are stored properly, the number of Schistosoma mansoni eggs in fecal smears remains countable for many months after preparation--a feature facilitating quality control studies in parasite control programs with limited resources. The present study compared egg recounts performed by independent microscopists in a total of 10,113 slides obtained in 19 annual or biannual audits with the original counts made by Division of Vector-borne Diseases (DVBD) microscopists in Kenya's Machakos and Makueni Districts in 1984-96. Recounts were performed 1-18 months after initial slide preparation. The overall proportion of discrepant counts in the 12-year study period was 6.83%. The majority of discrepant counts involved light infestations (50 eggs/g). At each audit, more slides were recorded as positive by DVBD microscopists and negative by the auditor than were recorded as negative by the DVBD and positive by the auditor. This trend is presumed to reflect Kato slide deterioration--especially a drying out before storage in hot, dry weather--between the initial count and the audit. Mean DVBD egg counts declined steadily between audits 10 (1989) and 19 (1996) in tandem with intensified treatment campaigns in the area. These findings confirm the suitability of this technique for quality control in programs with limited funds.

An evaluation of surveillance of malaria at primary health care level in Kenya.

As less than twenty five per cent of persons suffering from malaria seek formal treatment in most of sub-Saharan Africa, Facility-based morbidity statistics are inadequate for monitoring malaria control programmes. This explorative study assessed whether a health centre equipped with a microscope and trained personnel could monitor malaria transmission within its catchment area. The study was conducted at Chemase Health Centre in Nandi District in Kenya, an area holoendemic for malaria with Anopheles gambiae as the main vector and Plasmodium falciparum as the commonest cause of malaria. From first August to 31 October 1991, first seven children under five years of age on each working day accompanied by their mothers to the maternal and child health clinic were studied. A general examination was performed by a Registered Clinical Officer (Medical Assistant) and thin and thick blood smears made, stained with Giemsa stain and examined for malaria parasites by a Medical Laboratory Technologist. Mothers were interviewed by enrolled community nurses on antimalarial measures they were using in their homes. Four hundred and fifty five children mostly under five years of age, consisting of 48.1% males and 51.9% females, were studied. Malaria parasites were present in 209 (45.9%) blood smears of the children. The percentage of blood smears positive for malaria parasites was high in children below 36 months of age. There was a tendency for low percentage of blood smears positive for malaria in children whose mothers reported using mosquito nets or insecticide sprays. The study did not interrupt the routine of the health centre. Periodic monitoring of new malaria illnesses. and percentage of blood smears positive for malaria parasites in children aged 0 to 35 months should be introduced into health centre practice in Kenya. This catchment area approach could be used to monitor malaria control programmes as well as predicting malaria epidemics.

PIP: Traditionally, new cases are used to assess the presence and level of transmission of malaria. In sub-Saharan Africa, where only 8-25% of persons suffering from malaria use formal health services for treatment, facility-based morbidity statistics are inadequate for monitoring malaria control programs. The present study investigated whether children and mothers attending a primary health care center equipped with a microscope and trained personnel could serve as a basis for such monitoring. The first 7 children under 5 years of age presenting to Chemase Health Center in Kenya's Nandi District each day in a 3-month period in 1991 were enrolled, yielding a cohort of 455 children mostly under 5 years of age. A general examination was performed by a Registered Clinical Officer and thin and thick blood smears were prepared and examined for malaria parasites. Parasites were detected in 209 blood smears (45.9%), with the highest prevalence among children under 36 months of age. Mothers who reported use of mosquito nets or insecticide sprays were less likely to have children with malarial infection. Periodic monitoring of new malaria illnesses and the percentage of blood smears positive for malaria parasites in children 0-35 months of age should be introduced into health centers in Kenya in order to monitor malaria control programs and predict epidemics. Personnel reported that the study did not interrupt normal health center routines.

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

Field trial of permethrin impregnated sisal curtains in malaria control in western Kenya.

A trial to determine the effectiveness of sisal eaves-curtains impregnated with permethrin for malaria control was conducted in the malaria holoendemic western Kenya between 1991 and 1993. Indoor resting densities of Anopheles gambiae s.l. and Anopheles funestus were reduced by 90.9% and 93.8% respectively in protected houses. The entomological inoculation rate (EIR) was reduced by 72% in the intervention village. There was no significant reduction in vector longevity or survival as shown by the sustained high sporozoite rates. Monthly bioassays for retained insecticidal potency of permethrin on the fibre indicated vector mortality rates above 95% over the period. Of 283 and 240 children followed up from the intervention and control villages, a mean malaria prevalence of 43.2% and 52.2% respectively was observed over the trial period (p < 0.01). The prevalence rose to 73.5% and 75.7% (p = 0.541) respectively after the removal of the curtains. No significant differences were observed in the mean parasite density between the groups or between the proportions with parasite density exceeding 2,500 per microliter and with or without fever. The prevalence of splenomegaly was significantly lower in the intervention group compared to the control, both during (p = 0.005) and after the intervention (p < 0.001). There was no significant difference in the mean change in haematocrit at the end of the intervention. We observe that permethrin impregnated sisal curtains effectively retain permethrin, alter favourably the indoor vector density and EIR, and could provide a reduction in malaria prevalence.