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The World Health Organization (WHO) treatment protocols for cystic echinococcosis (CE) are based on the standardized ultrasound (US) classification. This study examined whether the classification reflected the natural history of CE in untreated and albendazole-treated patients. Data were collected during mass US screenings in CE endemic regions among transhumant populations, the Turkana and Berber peoples of Kenya and Morocco. Cysts were classified using the WHO classification. Patient records occurring prior to treatment, and after albendazole administration, were selected. 852 paired before/after observations of 360 cysts from 257 patients were analyzed. A McNemar-Bowker χ 2 test for symmetry was significant (p < 0.0001). 744 observations (87.3%) maintained the same class, and 101 (11.9%) progressed, consistent with the classification. Regression to CE3B occurred in seven of 116 CE4 cyst observations (6.0%). A McNemar-Bowker χ 2 test of 1414 paired before/after observations of 288 cysts from 157 albendazole-treated patients was significant (p < 0.0001). 1236 observations (87.4%) maintained the same class, and 149 (10.5%) progressed, consistent with the classification. Regression to CE3B occurred in 29 of 206 CE4 observations (14.1%). Significant asymmetry confirms the WHO classification’s applicability to the natural history of CE and albendazole-induced changes. Regressions may reflect the stability of CE3B cysts. [ABSTRACT FROM AUTHOR]

Precise knowledge of the natural history of cystic echinococcosis (CE) in humans remains somewhat arcane. The aim of the present study was to determine whether aspects of the natural history of established human infection with Echinococcus granulosus could be investigated by using a cross-sectional approach, in a community where CE was endemic. A mass ultrasound-screening survey, coupled with a questionnaire to record all previous surgical histories related to CE, was carried out amongst the primarily transhumant Berber people of the Mid Atlas mountains in Morocco. During two periods of intensive screening, of 10 days in May 2000 and 11 days in May 2001, 11,612 people, representing > 98% of the local population, were checked. One hundred and twenty six (1.1%) of the subjects — 75 (59.5%) of the 6864 females investigated and 51 (40.5%) of the 4748 males — were found ultrasound-positive for CE. Overall, 14.1% of the CE cases detected were children aged 1–15 years (who made up 44% of the study population). Most (77.4%) of the ultrasound-positive subjects investigated were also found seropositive for CE. The frequency of a past history of surgery for CE increased with subject age (P = 0.024), 125 (1.1%) of the subjects being recorded as having had such surgery. The frequency of surgery for pulmonary CE was relatively constant in all age-groups, indicating that infection can occur at any time. The frequency of abdominal CE increased with age (R2 = 0.8102). Assuming that the incidence of infection remains fairly constant over time and that the longer a person spends in this endemic area the more likely it is that he or she will develop CE, then a progression from active through transitional to inactive CE should occur. The cysts observed by ultrasound in the present study were categorized, as type 1, 2, 3, 4 or 5, according to the new, standardized, ultrasound classification of CE developed by the World Health Organization (WHO). There was a clear exponential decline in the frequency of the various cyst types, from type 1 (the most frequent) to type 5 (the rarest). This decline validates the assumptions made, about the natural history of established CE, by those who developed the WHO's classification. The classification should therefore be invaluable to surgeons and clinicians, when they have to consider treatment options for patients with the various types of CE, and to policy makers trying to establish the economic costs of treating CE in endemic settings. [ABSTRACT FROM AUTHOR]

The public health educational impact of community-based ultrasound (US) surveys for cystic echinococcosis (CE) can form an important part of the development about the awareness of the importance of the disease in an endemic area. In addition to identifying asymptomatic carriers and thereby facilitating early diagnosis and treatment, such surveys can be used to impart important educational messages at the individual, household, community, regional and national levels. US surveys are usually appealing to rural communities where such services are not available but where the technique is generally appreciated by its application in a wide field of medical applications. The qualities of the test (painless, non-invasive and gives instant recordable results) are also attractive to participants during such surveys and the majority of the population in a selected study area choose to be screened. Two such surveys were carried out amongst the Berber people of the mid-Atlas mountains in central Morocco in May 2000 and 2001. Over 11,000 people were screened in the two 10-day surveys. Informed consent had been obtained through community meetings and with the chiefs of villages prior to the surveys being conducted. Individuals who volunteered to be screened entered the study and as far as is known there were no refusals. The concept of voluntary participation, the explanation of the life cycle and clinical manifestations of the disease and its prevention are all-important educational messages. The occurrence of CE is almost always known in an endemic community but is usually very poorly understood leading in many cases to a fear of the disease, especially amongst families with an infected individual who has previously undergone surgery. During the US survey considerable attention was paid to provide educational input before, during and after the survey. Information was provided at the start of the survey to local leaders, doctors, veterinarians and school teachers on the aims of the study and to obtain informed consent. At the start of the study everyone was individually schooled about the route of transmission of the parasite and how this may be best prevented. The knowledge level of those screened was assessed by showing hydatid cysts, either freshly obtained from the abattoir of from photographs. Animal cysts were recognised by almost everyone but its transmission and link to human disease was invariably unknown. Patients found to be infected with CE were always confidentially counselled and followed up for treatment, if required. Treatment options were explained to the individual or to parents in the case of a child. Local physicians participated in discussions on the WHO guidelines for the treatment of CE and all cases were fully discussed providing an educational element for the local doctors. The 1% US prevalence found sent an important message to the local politicians and the perceived importance of the disease had an impact at the leadership level. Local leaders made calls for a control programme. The long term educational impact remains to be evaluated as does the role such surveys play in the future collaboration of communities with the implementation of a control programme. [Copyright &y& Elsevier]