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Background: Tuberculosis (TB) and malaria are endemic and are major public health burdens in Nigeria. Sputum smear microscopy for AFB and malaria microscopy are important for laboratory diagnosis and management of TB and malaria respectively. The \Vorld Health Organization has recommended the integration of malaria microscopy Quality Assessment (QA) with that of other microscopically diagnosed diseases, but there is no published evidence about the feasibility of implementing this policy in a resource poor setting in sub-Saharan Africa. Hypothesis: It is feasible to develop a model Quality Assessment (QA) system for malaria microscopy built on the existing TB microscopy QA system, in the context ofthe Nigerian health system. Objectives: To assess the feasibility oflinking malaria microscopy quality assessment into the existing AFB microscopy quality assessment system in Kano, Nigeria. Materials and methods: Five TB microscopy centres were selected for implementing the integrated TB and malaria microscopy QA scheme in the state. A model system was designed based on the Lot Quality Assurance System for selecting and blinded rechecking ofTB and malaria slides from these laboratories. Supervision and evaluation was conducted at 3 monthly intervals for 24 months. Results: Microscopy tests made up 21% of the laboratory tests conducted in one year in Kano state. The proportion of malaria and AFB microscopy among the microscopy tests was 35.1% and 27.2% respectively. To implement the model the five laboratories selected for implementing TB and malaria microscopy quality assessments had at least one microscope and two microscopists covering both TB and malaria. Full integration of the QA for TB and malaria microscopy was achieved in two laboratories, and partial integration in two other laboratories. The system improved the quality of TB and malaria microscopy results, particularly specificity. The average specificity of TB microscopy from the five laboratories increased from 80% to 97.9% and for the two laboratories in which malaria microscopy QA was fully integrated it increased from 76.0% and 66.7% to 100%. The average specificity of malaria microscopy from the two laboratories increased from 77.8% to 80.0%. On average, the concordance rate of TB microscopy results increased from 81% at baseline to 91.0% at the final assessment. For malaria microscopy the concordance rate increased from 69.2% at the baseline, to 83.3% at the final assessment in . one laboratory, but decreased from 100% to 83.3% in the other laboratory due to 16.7% false positive results. Increases in the concordant TB and malaria microscopy results were positively associated with the ability of the laboratories to prepare and stain the TB and malaria slides. There was a decreased false positivity and false negativity rates of TB microscopy results in all the five laboratories. Conclusions: It is feasible to integrate the QA system for TB and malaria microscopy and the assessment improved the quality of both services. However, a lot of advocacy is needed to engage all the relevant stakeholders and the integrated system needs testing out in different settings in order to be able to develop sound recommendations to guide the complex scaling up process.

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J. P. HEATH: A light and electron microscopical study of the mechanisms of pathogenicity of Trichomonas vaginalis, in epithelial cell cultures. T. vaginalis is a urogenital protozoan parasite of man, causing the disease known as trichomoniasis. In males the disease is often symptomless; in females acute infections are often associated with inflammation of the cervical and vaginal walls, superficial erosions of the vaginal epithelium and a heavy, purulent vaginal discharge. In this study I have used an in vitro model of trichomoniasis in order to elucidate some of the mechanisms of pathogenicity of the parasite. The behaviour and cytopathogenicity of T. vaginalis in epithelial cell cultures was examined using phase contrast and interference reflection light microscopy, and scanning and transmission electron microscopy. The trichomonads attack the epithelial cell monolayers causing pathological changes within the cells which lead to the detachment and lysis of the cells. The lysed cell debris is phagocytosed by the trichomonads. Two aspects of the behaviour of T. vaginalis are of prime importance in the pathogenic processes that lead to the death of the cell cultures: 1) T. vaginalis readily adheres to the exposed surfaces of the epithelial cells and to the glass substratum on which the cells are grown. The adhesions are of the intermediate junction type, characterised by a gap of 10 - 20 nm. Damage to the monolayer of epithelial cells is restricted to those cells with adherent trichomonads. 2) When T. vaginalis adheres to a solid substratum it loses its characteristic spherical shape which is assumed in suspension and it develops pseudopodia which it uses to locomote in an amoeboid manner. The amoeboid trichomonads are capable of migrating between and under the monolayer mechanically breaking the adhesions of the cells to each other and to the substratum. The pseudopodia, and regions of active phagocytosis, of T. vaginalis contain actin-like microfilaments. Mechanisms that may be involved in the adhesiveness and amoeboid movements of T. vaginalis are discussed, and the possible relevance of these phenomena and of chemical factors to the cytopathogenicity of T. vaginalis in cell cultures and in humans is considered.

In this study the influence of physical factors on the survival and infectivity of S. mansoni and S.haematobium miracidia was compared. The physical factors studied include termperature, light, gravity, depth, hydrostatic pressure, host-parasite dispersion, rate of flow of water and turbulence, ultra-violet radiation and the length of contact time. While the influence of one physical factor was being investigated all the others were kept constant and the levels of each factor applied were chosen in order to include the limits that may be encountered in the field. The criteria for the influence of a physical factor on miracidia were the infection rates produced in susceptible snails. In some cases the factor was applied to the miracidia alone for a period of time before exposing the snails to them. Miracidia were examined under a dissecting microscope for mortality or degree of activity of survivors, where the factor (such as temperature or ultra-violet radiation) affected their metabolic rates. The degree of activity of miracidia which indicated the extent to which a physical factor affected them was described as "ACTIVE", "SLOW" or "LETHARGIC" and was quantified by calculating the mean rates of movement of miracidia in those categories. For factors which acted as stimuli, such as light and gravity, the responses of the miracidia were recorded as a positive or a negative taxis. The use of carefully designed apparatus and simplified methods made it possible to reproduce the experiments several times, and statistical analysis of the results helped to assess the significance of differences obtained. These studies have shown that the survival and infectivity of S.mansoni and S.haematobium miracidia were influenced in a very similar manner by the different physical factors and that both parasites have a remarkable capacity to locate, select and infect their snail hosts. It was found that they were not limited by depth, hydrostatic pressure or dispersion and that they were capable of infecting snail hosts in water flowing at moderate rates. The different responses of S.mansoni and S.haematobium miracidia to light and gravity appear to increase their chances of meeting their particular snail hosts. The use of the physical factors studied to interfere with the infective capacity of schistosome miracidia and thereby reduce transmission in endemic areas has been discussed.

A field study on the ecology and epidemiology of S. haematobium was carried out in 8 different parts of the Volta Lake from November 1978 to June 1980. Snail sampling for B. rohlfsi was conducted monthly in 39 lakeside villages and data on human prevalence rates and egg counts were obtained in 30 of the villages. A detailed, integrated study of S. haematobium was conducted at the large lake- side village of Agbenoxoe. The snail sampling technique was an efficient version of the man- time method. For screening urine samples for S. haematobium eggs, the "Nuclepore" filtration method was used - its first large-scale, field application. At Agbenoxoe, a new method of recording water contact data was initiated. From snail sampling, it was learned that S. haematobium trans- mission was distinctly seasonal, and intensity varied according to the type and amount of vegetation in water contact points (WCPs), the shape of the WCPs, and their geographical location. S. haematobium infection rates in B. rohlfsi around the lake were among the highest in the world. The snail had a high intrinsic rate of natural increase, but could not maintain an equilibrium population in the unstable habi- tat of the lake. An original mathematical model was developed to describe the dynamics of S. haematobium transmission to B. rohlfsi. S. haematobium prevalence rates and egg counts were exceptionally high in 2 lake sections - the Afram and Obosum branches - mainly because of past and present growth of Ceratophyllum which led to high transmission during most months of the year. However transmission became interrupted when Ceratophyllum density became too great and decayed in WCPs. Levels of infection were lower in the other lake sections surveyed, mainly because of less Ceratophyllum growth which confined high transmission to December to March each year. Analysis of all the human data revealed that the 5- 19 year-old age span was responsible for 93% of the potential contamination of S. haematobium eggs in the Volta Lake. At Agbenoxoe, snail sampling, prevalence, egg count, incidence, and water contact data fit together to paint a uniform picture of very focal and seasonal transmission.

A general review of cutaneous leishmaniasis (CL) and its management is followed by a retrospective review of 306 cases of CL in British soldiers from Belize. The diagnosis was confirmed by demonstration of the parasite, by histology and/or culture, in 61% of cases. Leishmania braziliensis braziliensis (Lbb) was identified in 78 cases and Leishmania mexicana (Lmm) in a further 29 cases. Only cases in which the parasite was identified were analysed further. A single lesion was present in 71%, usually on the exposed extremities. The mean diameter of the ulcers was 14.4mm and lesions had been present for a mean of 9.9 weeks before treatment started. Those due to Lbb were larger, yet they had been present for a shorter time than those due to Lmm. There were no other distinguishing clinical features between them. Treatment with sodium stibogluconate was effective. A 10 day course of 600-800mg od healed 48.5%, whereas a 14 day course of 600 mg bd healed 63.9%. A total of 24g of sodium stibogluconate healed the ulcers of 90% soldiers irrespective of the regime used. Reports of myalgia, anorexia and malaise were more frequent in those who received the higher daily dose. A transient leucopenia and a rise in serum aminotransferases were noted during treatment. These studies led me to propose some management guidelines. The diagnosis should be confirmed histologically and by culture. Sodium stibogluconate 20mg/kg/day should be administered for 20 days. Patients should be assessed 6 weeks after the completion of treatment both clinically - complete epithelialisation with a flat, non-indurated, scar, and by culture of a biopsy.

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