[The incidence of neurological disorders in tropical South America. Experience in the Bolivian lowlands].

Background: The Chiquitano tribe lives in the southern Amazonas region in Bolivia, remote from larger towns. Data on the epidemiology of neurological disorders are completely lacking.
Methods: A combined prospective-retrospective study was designed to determine the prevalence and annual incidence of major neurological diseases. In an one-year prospective study 1514 individuals (total population 5652) who consulted the general practitioner were interviewed and examined for neurological disturbances. These histories were analysed retrospectively by a neurologist and classified according the diagnosis key of the DGN.
Results: During a one-year period (April 1995-March 1996), 139 patients suffering from neurological diseases were seen (one-year incidence and prevalence 2.45%). Cervical and lumbosacral pain syndromes were the most common neurological problems; these were caused by sleeping in hammocks, and by hard agricultural labour. Tropical myositis (12.9%) was very frequent and the most frequent muscle disease. Epilepsy was found in 11 patients and extrapyramidal syndromes in 2 patients. Regarding epilepsy, a high dark rate is assumed because of social and cultural traditions. Strokes are rare, since many risk factors are not present. All cases of meningitis were lethal and clearly demonstrated infrastructural problems. Patients with social diseases (AIDS, drug- and alcohol addiction, injuries caused by violence) were rarely seen.
Conclusion: In a shrinking world, and with the development of "Tropical Neurology" as a specialised discipline neuroepidemiological data are increasingly important for two reasons. First of all, they sensitise neurologists to this topic, and secondly, they can be used to estimate the need for neurologists serving the Third World's minority populations.