Clinical and radiological prevalence of skeletal fluorosis among retired employees of Wonji-Shoa sugar estate in Ethiopia.

OBJECTIVE: To study the clinical and radiological prevalence of skeletal fluorosis among the retired employees of Wonji-Shoa sugar estate. DESIGN: Retrospective and cross-sectional study. SETTING: Wonji-Shoa sugar estate, an agro-industrial estate located in the Ethiopian Rift Valley. SUBJECTS: Two hundred and sixty three employees of the estate who retired between 1995 and 1996. MAIN OUTCOME MEASURES: Clinical evidence of impaired squatting, neck and lumbar mobility, kyphosis, and X-ray evidence of fluorosis. RESULTS: Skeletal fluorosis was more evident among the males (p<0.05), and the prevalence was higher among the factory and the agricultural workers than among the administrative workers (p<0.05). Clinical prevalence was 20% versus the radiological prevalence of 70.3%, indicating that many cases were asymptomatic. Impaired neck and lumbar mobility and impaired squatting significantly agreed with the radiological diagnosis (p<0.05) while kyphosis was not. CONCLUSION: Further clinical and epidemiological studies are suggested and strengthening of the existing defluoridation programmes within the area is recommended.

Leprosy.

Leprosy is a unique infectious disease with a prolonged incubation period and a predilection for skin and nerves. The involvement of nerves by the primary infection as well as the immunologically mediated reversal reactions result in impairment of nerve function and severe disabilities. The introduction of the World Health Organization Multi Drug Therapy over the last two decades has produced dramatic changes in the management and control programmes of leprosy. A recent important contribution to the understanding of leprosy pathogenesis has been the elucidation of the molecular basis for the entry of Mycobacterium leprae into the Schwann cell and the peripheral nerve. Leprosy still remains the commonest cause of peripheral neuropathy in developing countries.

Distribution of fluoride and fluorosis in Ethiopia and prospects for control.

A review and mapping of fluoride test data for 270 water sources in 126 communities and examination of the literature of fluorosis distribution in Ethiopia show that this health problem extends beyond the Rift Valley into some highland communities. Fluoride concentrations above 5.0 mg/l in the Rift Valley were found mostly in hot springs (100% of all sources), lakes (78%), shallow wells (54%) and boreholes (35%) and the lowest concentrations (below 1.5 mg/l) in springs and rivers. Analysis of hydrochemical, economic and demographic factors in the spatial distribution of high-fluoride domestic water sources indicates that the fluorosis problem has become more serious in the Rift Valley in recent decades. Considerable spatial variation in the occurrence of fluoride, even within the same communities, and the presence of some low-fluoride water sources in the Rift Valley offer possibilities for geochemical exploration for acceptable domestic sources. The defluoridation programme in the Wonji irrigation scheme illustrates the problems faced by a large rural community in a developing country. Possibilities for control are examined and recommendations made for the development of alternative water sources and promising defluoridation methods using locally available materials and technologies.

Psychosocial assessment of lathyrism patients in rural Estie district of South Gondar, northern Ethiopia.

Three hundred and thirty three patients in the lathyrism endemic rural Estie district of Northern Ethiopia were interviewed and examined to assess the psychosocial impacts of neurolathyrism. The majority of the affected were in the age group of 11-20 years (43%) followed by 21-30 years (29%). Males were more affected than females (4.8:1). Peak occurrences of neurolathyrism was observed at time of mobilization of the population in villagization and land diversification schemes. Females were affected to lesser extent and at an earlier age than males. Neurolathyrism affected matrimony among the rural farming population where marriage is considered as the most significant social achievement of any young member of the society. Divorce rate due to paralysis was 28%. It also influenced the choice of occupation among the afflicted rural people. Many males went into ecclesiastical professions. A significant number of males also took up occupations which traditionally were considered to be exclusively for women like basketry and embroidery. More females, not withstanding their age, were engaged in cattle-keeping. During the study, the rural communities were made aware of the association of neurolathyrism and consumptions of grass pea seed. It is believed that this step will enable communities to use home-based detoxifying methods and resort to alternate crops during times of food shortage.

Prevalence of antibodies to hepatitis C virus among patients with leprosy in several African countries and the Yemen.

The prevalence of anti-HCV was determined in 1,309 leprosy patients and a control group of 1,469 subjects from 6 sub-Saharan African countries and the Yemen. Sera found positive by an initial second generation ELISA were subjected to 3 additional confirmatory tests. The anti-HCV prevalence in leprosy patients (7.1%) was significantly higher than in the control group (2.6%). HCV seroprevalence increased with age in both the control and leprosy groups. No statistically significant difference could be found between anti-HCV prevalence and the several clinical forms of leprosy among patients. The results of this study indicate a high degree of exposure or chronic carriage of hepatitis C among leprosy patients.

The epidemiology of lathyrism in north and central Ethiopia.

Lathyrism is a neurotoxic disorder caused by excessive, prolonged consumption of the hardy, environmentally tolerant legume, the grass-pea, Lathyrus sativus, which contains the neurotoxic amino acid beta-N-oxalylamino-L-alanine acid (BOAA). The disease develops after heavy consumption of grass-pea for over two months. It is uniformly manifested by a predominantly motor spastic paraparesis with varying degrees of disability. A door-to-door epidemiological survey for the disease using trained lay health workers was carried out in the major areas of northwest and central Ethiopia where L. sativus is grown. For security reasons, some of the other endemic areas wre not accessible for the survey. The survey involved a population of 1,011,272. A total of 3,026 affected persons were identified. The disease was found to be widespread in the northwest and central highland areas of the country. The prevalence rates ranged from 1/10,000 to 7.5/1,000. The highest prevalences were in North and South Gonder, and East and West Gojam. The male:female ratio of cases was 2.6:1; the females exhibited a milder form of the disease. The cultivation of L. sativus is increasing in Ethiopia, which makes the development of low-BOAA strains very important in order to control the high incidence of lathyrism, a crippling disease which affects the productive young members of the society.

DNA fingerprinting in the epidemiology of African serogroup A Neisseria meningitidis.

The restriction endonuclease (RE) technique was used to compare 172 meningococcal group A strains collected between 1969 and 1990, mainly from countries of the so-called African Meningitis Belt, the Gambia and Ethiopia. The 64 strains from various African countries (Niger, Chad, Burkina Faso, Cameroon, Morocco, Djibouti) were distributed within 3 main restriction enzyme patterns (REPs); the 77 Gambian strains fell into 5 REPs and the 24 Ethiopian strains into 2 such patterns. Several of the main REPs were formed by clusters of closely related clones. Clones, very similar to dominating REPs of the 1960s in Niger, Burkina Faso and Cameroon, were in the 1980s found to be strongly represented in the Gambia to the extreme west of the Meningitis Belt. One of the Gambian clones from 1983-86 was identical to an Indian clone recovered in New Delhi 1986-87. Another clone was detected in 1983 in the Gambia, in 1989 again in the Gambia as well as in Ethiopia, and in 1990 in Tanzania. Our results are largely in line with those of previous studies based on modern techniques of protein and isoenzyme electrophoresis. The RE method is useful mainly for the exact genotypic differentiation of closely related clones, and seems to be a valuable complement to phenotypic tools for epidemiological mapping of Group A meningococcal infection.

Low HTLV-1 seroprevalence in endemic tropical spastic paraparesis in Ethiopia.

Tropical spastic paraparesis (TSP), a chronic progressive myelopathy, occurs in Ethiopia in epidemic form as neurolathyrism, while the endemic form has remained obscure. We describe the clinical features of 22 patients with TSP and the results of screening for HTLV-1 in these patients, 26 patients with other neurological disorders, 14 patients with leukaemia and 66 blood donors. The major manifestations in the patients with TSP were weakness and spasticity of the lower limbs with upper motor neurone signs and minimal sensory loss and bladder dysfunction. Two patients with TSP (9%), 2 patients with other neurological disorders (7.7%) and one patient with leukaemia and deafness were seropositive for HTLV-1. All the 66 blood donors were seronegative. Our results suggest that HTLV-1 may not play a major role in the pathogenesis of TSP in Ethiopia.

Epidemiological pattern of leprosy in Ethiopia: a review of the control programmes.

Leprosy control started in a limited area of Ethiopia in 1956. Extended coverage of the country was achieved in the early seventies. Review of the data from the control projects since 1976 revealed that leprosy is a disease of the Ethiopian highlands where prevalence rates as high as 7 per thousand have been recorded in some provinces, while the cumulative national average for the last 13 years was 2.6 per thousand. The paucibacillary form was predominant. However, unlike other African countries, a relatively high proportion of multibacillary leprosy was found in Ethiopia. The male-to-female ratio was 2:1 with the highest prevalence in the 15-44 years age bracket. Detection rates for new cases have shown a gradual decline since 1982, a year before multiple drug therapy (MDT) was introduced into the country. For the last 5 years the number of new cases has stabilized at 4700/year. These trends probably reflect a general reduction in the prevalence of leprosy in the country, while the conspicuous decline in 1982 is most likely related to discharge of cases during screening before MDT. The new villagization policy of Ethiopia with its effective reorganization of the populations is believed to make control programmes and supervision of MDT easier and presumably more effective. Similarly, more reliable prevalence and incidence studies could be undertaken with success.

Lathyrism in rural northwestern Ethiopia: a highly prevalent neurotoxic disorder.

Lathyrism is a disorder of the central motor system, induced by heavy consumption of the grass-pea, Lathyrus sativus an environmentally tolerant legume containing the neurotoxic excitatory amino acid beta-N-oxalylamino-L-alanine (BOAA). A complete door-to-door resurvey of the Dembia and Fogera regions of northwestern Ethiopia, areas endemic for lathyrism, revealed an estimated mean disease prevalence of 0.6%-2.9%. Most patients developed the disease in the epidemic of 1976/77, although new cases appear to have occurred with an estimated mean annual incidence of 1.7:10,000. Production and consumption of grass-pea is increasing in Ethiopia, making attempts to develop low-BOAA strains to prevent lathyrism increasingly important.

Community-based study of neurological disorders in Ethiopia: development of a screening instrument.

This paper describes the development of a screening instrument for a community-based neuroepidemiological survey in a rural community in Ethiopia. A pilot study in 1984 to pre-test the questionnaires developed revealed that epilepsy, poliomyelitis, mental retardation and speech disturbances were the most common neurological disorders among the 3,000 rural inhabitants surveyed. The study suggested that a base-population of about 50,000 was required for a future major epidemiological survey to identify rare neurological disorders.

Neurological complications of endemic skeletal fluorosis, with special emphasis on radiculo-myelopathy.

The results of surveys carried out between 1976 and 1985 in the fluorosis-endemic area of the Ethiopian Rift Valley is summarised, with emphasis on the neurological complications resulting from the crippling osteofluorosis. The neurological manifestations in the forms of myelopathy with and without radiculopathy (respectively 72% and 28%) occurred after exposure to high fluoride (greater than 4 ppm) for longer than 10 years. These deficits were clearly found to be a consequence of fluoride deposition in bones, resulting in generalised sclerosis and osteophytosis, with reduction in the diameter of the intervertebral foramina and of the spinal conal. Advanced osteosclerosis commonly causes severe spastic quadriparesis in flexion, accompanied by distressing spasms and urinary incontinence. The dilemma of these medical problems in relation to the agro-industrial economic developments of the Ethiopian Rift Valley is discussed.

Cerebrovascular accidents in Ethiopia.

The causes, risk factors and outcome of cerebrovascular accidents (CVA) in 150 patients admitted to Tikur Anbessa Hospital, Addis Ababa, Ethiopia, between 1983 and 1985 were studied. Cerebral thrombosis was the commonest cause of CVA (50.6%), followed by cerebral haemorrhage (24%) and cerebral embolism (15%). The single most important risk factor for CVA was hypertension. Mortality was highest with cerebral haemorrhage (89.4%) and lowest with cerebral embolism (13%). An important measure which could reduce the incidence of CVA is the vigorous and sustained control of hypertension.

Ceftriaxone in the treatment of septicaemia due to multiple drug resistant bacteria.

Ceftriaxone, a highly effective, B-Lactamase resistant broad spectrum parenteral cephalosporin was used in the treatment of 26 consecutive patients with clinically and/or bacteriologically resistant infections at the Addis Ababa University Tikur Anbessa and Ethio-Swedish Paediatric Teaching Hospitals. The patients who had failed to respond to a combination of two or more previously appropriate antibiotics were treated with ceftriaxone administered in two divided doses (daily 50-100 mg/kg) in children and a single dose of 2-3 gm in adults for an average duration of 9.9 days. Of the 21 evaluable cases 16 (76%) were cured, three died and two developed superinfection with Pseudomonas and Staphylococcus species. Primary pathogenic bacteria were eradicated from all the 21 bacteraemic patients on the third day of therapy. Twelve of the 21 patients had serious underlying conditions. Except for the two superinfections, the results of the trial confirm that ceftriaxone is a very potent and effective agent in the treatment of resistant bacteraemic infections. No significant adverse effect of the drug was encountered during the therapy.

Characteristics of serogroup A Neisseria meningitidis responsible for an epidemic in Ethiopia, 1988-89.

In September 1988, an epidemic of meningococcal disease started in Ethiopia. 21 Neisseria meningitidis isolates recovered from patients in Addis Ababa and towns 200 km south of the capital were characterized by serogrouping, serotyping, testing of susceptibility to antibiotics, restriction endonuclease fingerprinting, and multilocus enzyme electrophoresis. The 21 isolates were essentially homogeneous for all properties tested and belonged to clone III-1 of serogroup A N. meningitidis, which was also responsible for the epidemics in Saudi Arabia in 1987 and in Sudan and Chad in 1988.

Endemic fluorosis in the Ethiopian Rift Valley.

Between 1977 and 1985, the fluoride content of drinking water and the incidence of endemic fluorosis were assessed and correlated in 16 large farms, villages and towns in the Ethiopian Rift Valley. The fluoride level of drinking-water collected from wells there ranged from 1.2 mg/litre to 36.0 mg/l (mean 10.0 mg/l). Dental fluorosis was observed in more than 80% of sampled children resident in the Rift Valley since birth, with maximum prevalence in the age-group 10-14 years; 32% of the children showed severe dental mottling. Males were affected more than females. Three areas, Wonji-Shoa, Alemtena and Samiberta, were identified as having cases of skeletal fluorosis. The highest incidence was at Wonji-Shoa sugar estates, where a linear relationship was observed between the development of crippling fluorosis, fluoride concentration of drinking-water, and period of exposure to it. The first cases of skeletal fluorosis there appeared among workers (98% males) who had been consuming water with fluoride content of more than 8ppm for over 10 years. Among 30 workers with crippling skeletal fluorosis, cervical radiculo-myelopathy was found to be the commonest incapacitating neurologic complication. As a preventive measure, low-fluoride surface water should be supplied for drinking wherever feasible; if this is not possible, the development of partial defluoridation should be considered.

Muramidase (lysozyme) findings in sural and radial nerve biopsies in leprosy patients after varying periods of treatment.

Using the immunoperoxidase staining method, tissue muramidase (lysozyme) activity was studied in 34 nerve biopsies from leprosy patients and compared to findings in the skin. In a majority of lepromatous and borderline-lepromatous leprosy patients, the enzyme was seen to form a saccular pattern within the cells; whereas a granular pattern was found at the tuberculoid end of the leprosy spectrum, as well as during reversal reactions. Indeed, the most intense enzymatic activity was found in four patients with reversal reactions. Compared to the skin, muramidase activity was found to be more intense and persisted longer in the nerves. Successful antileprosy treatment reduced the enzymatic activity in both the nerves and the skin, but more so in the skin. Schwann cells and axons did not show muramidase activity, indicating that the muramidase-positive cells are not of neuronal origin. Our results suggest that a high percentage of mononuclear cells infiltrating the peripheral nerves in leprosy are derived from blood monocytes. The function of tissue muramidase in leprosy is not yet clear. Its peculiar intracellular distribution pattern in the different forms of leprosy, however, warrants further study to elucidate its role in the pathogenesis of the disease.