Biosurfactant production by halophilic yeasts isolated from extreme environments in Botswana.

Nine morphologically distinct halophilic yeasts were isolated from Makgadikgadi and Sua pans, as pristine and extreme environments in Botswana. Screening for biosurfactant production showed that Rhodotorula mucilaginosa SP6 and Debaryomyces hansenii MK9 exhibited the highest biosurfactant activity using Xanthocercis zambesiaca seed powder as a novel and alternative inexpensive carbon substrate. Chemical characterization of the purified biosurfactants by Fourier Transform Infra-Red spectroscopy suggested that the biosurfactant from R. mucilaginosa SP6 was a rhamnolipid-type whereas the biosurfactant from D. hansenii MK9 was a sophorolipid-type. The two biosurfactants exhibited antimicrobial activities against eight pathogenic bacteria and fungal strains (Proteus vulgaris, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Micrococcus luteus, Cryptococcus neoformans, Candida albicans and Aspergilus niger). The sophorolopid-type biosurfactant was found to be the most potent among the antimicrobial drug resistant strains tested. The findings open up prospects for the development of environmentally friendly antimicrobial drugs that use an inexpensive source of carbon to reduce the costs associated with the production of biosurfactants.

Socio-cultural dimensions of leprosy in north-western Botswana.

A study to determine some socio-cultural factors influencing knowledge and attitudes of the community toward leprosy was carried out in north-western Botswana, where cases of leprosy have been known to exist over the years. The study was largely qualitative, using ethnographic approaches. The research was tailored in a way to capture the ethnic diversity of the region, in particular two ethnic groups, namely Bayei and Bambukushu. The name or symptom complex associated with leprosy was 'ngara' or 'lepero' and this was associated with bad blood. Knowledge on disease causation was lacking, which in turn influenced health seeking behaviour of patients. Patients were well integrated and accepted into the social structure of communities. Women caring for these patients did experience some additional burden and identified time as their major constraint in caretaking. It was apparent that the degree of rejection correlated with seriousness of the disease and extent of disabilities and dysfunction. The present pattern of health seeking behaviour needs to be altered, so that an early diagnosis can be made at the health facility. This will aid appropriate management and prevent occurrence of deformities and disabilities, which in turn will reduce rejection and isolation of patients. Education of community, patients, traditional and religious healers on various aspects of the disease, especially causation, is essential to achieve a change in the health seeking behaviour.

Knowledge and attitude of health workers towards leprosy in north-western Botswana.

The knowledge and attitude of health workers in north-western Botswana towards leprosy was determined by interviewing ninety nine health workers from various health institutions. Knowledge on causation of leprosy was generally lacking. Although majority of respondents knew that the disease is curable, less than half knew the correct duration of treatment. The attitude of service providers was influenced by poor knowledge, and more than a third claimed that patients should be isolated. The pattern of health seeking behaviour, initially traditional or religious healers and then modern health facilities, was a significant finding. In order to ensure early case detection and prevent deformities, it is vital that education of community, patients and health workers is provided to an extent that health seeking behaviour is altered. Traditional and religious leaders must also be included in such training sessions.

Case finding survey for leprosy in Botswana.

A baseline survey to establish the point prevalence of leprosy was carried out in July and August, 1991 in northern Botswana, where cases of leprosy have existed over the years. A total of 799 contacts of 127 index cases and 8235 school children from 18 schools were clinically screened for leprosy. In all, 44 active cases of leprosy were registered and started on multidrug therapy recommended by World Health Organization. Of these cases, 32% were newly identified during the survey. Due to the moderate outcome, surveillance and control of leprosy has been integrated with existing TB control programme. This is the first time ever a systematic attempt was made to establish a programme for control of leprosy in Botswana.

PIP: During July-August 1991, health workers conducted leprosy screening in Ngami, Okavango, Chobe, Boteti, and Mahalapye in northern Botswana to determine the point prevalence of leprosy. They screened 799 contacts of 127 index cases and 6235 school children from 9 secondary and 9 primary schools. During the contact survey, they detected 42 active cases of leprosy, whom they started on multidrug therapy. Only 2 students had active leprosy (paucibacillary cases). They lived in Okavango subdistrict. The health workers also started them on multidrug therapy. The surveys identified 14 (32%) new leprosy cases. Multibacillary leprosy was more common than paucibacillary leprosy (68% vs. 32%). Most cases (84%) were older than 25 years old. Most leprosy cases lived in Ngami and Okavango subdistricts (43% and 41%, respectively). The point prevalence of registered leprosy cases on multidrug therapy in the 5 subdistricts in northern Botswana was 0.18/1000. Since the surveys showed that leprosy prevalence is low, surveillance and control of leprosy activities have been integrated into the existing tuberculosis control program. This integration was the first time that a leprosy control program has been systematically attempted in Botswana.