Cystic echinococcosis in Spain: current situation and relevance for other endemic areas in Europe

Cystic echinococcosis (CE) remains an important health problem in many regions of the world, both where no control measures have been implemented, and where control programs have been incompletely successful with ensuing re-emergence of the disease. In Spain, official data on CE show an increase in the proportion of intermediate hosts with CE during the last few years, and autochthonous pediatric patients have been reported, a sign of active local transmission of disease. A similar picture emerges from data reported to the European Food Safety Authority by other European countries. Nevertheless, several crucial aspects related to CE that would help better understand and control the disease have not been tackled appropriately, in particular the emergence of infection in specific geographical areas. In this respect, while some data are missing, other data are conflicting because they come from different databases. We review the current situation of CE in Spain compared with areas in which similar problems in the CE field exist, and offer recommendations on how to overcome those limitations. Specifically, we believe that the introduction of national registries for CE with online data entry, following the example set by the European Registry for Alveolar Echinococcosis, would help streamline data collection on CE by eliminating the need for evaluating and integrating data from multiple regions, by avoiding duplication of data from patients who access several different health facilities over time, and by providing much needed clinical and epidemiological data that are currently accessible only to clinicians.     

Cystic echinococcosis in humans: our clinic experience

Echinococcosis in humans is a zoonotic infection caused by larval stages of cestode species of the Echinococcus genus. In cystic echinococcosis (CE), caused by Echinococcus granulosus, the liver is the first and the more frequent involved organ, followed by the lung. Heart, spleen, kidney and brain are usually less involved. The finding of a cyst in course of echinococcosis is usually fortuitous, during ultrasound examination, X-ray or CT. The Authors report 4 cases of human CE admitted to the Department of Infectious Diseases University of Naples "Federico II". Each case is peculiar both for the organ involved by the cysts and for the symptomatolgy. The abdominal pain, in case 1 caused by gallstones, allowed, by the ultrasound examination, to find several hydatid cysts in the liver, never symptomatic until then. The woman, in case 2, was operated for cysts in the lung, without receiving pharmacological prophylaxis. The same occurred in case 4, in which the lack of prophylaxis caused very serious relapses. In case 3, the young woman underwent an ultrasound examination because of an abdominal pain. A unique large cyst extended only in the spleen. The specific serology for immunoglobulin anti-E. granulosus resulted positive 1:61 (n.v. < 50). The Albendazole therapy caused the disappareance of pain, quickly. Later, the patient was splenectomized. It's not clear why only the spleen was involved and why the anti-E. granulosus serum levels of were increased only a little. The man, in case 4, was admitted with chest pain and electrocardiographic findings of myocardial anterior ischemia. He underwent surgical treatment of three hepatic cysts by E. granulosus, during the previous year. Two-dimensional echocardiography, transesophageal echocardiography, and cardiac magnetic resonance revealed a round cystic mass, 6 x 6 mm, located in the middle interventricular septum. The cardiac isoenzymes were in the normal ranges, but the anti-E. granulosus immunoglobulins were positive 1:5120 (n.v. < 64). The patient was treated with Albendazole. This caused the almost simultaneous disappearance of the circular cystic and clinical and electrocardiographic findings of myocardial ischemia. A cardiac hydatid cyst is an uncommon lesion, occurring in about 0.4-2% of patients with echinococcosis. In conclusion, Cystic echinococcosis is a problem in Mediterranean regions because of the high population of stray dogs, favourable conditions created by man and, above all, the illegal slaughtering.     

Human cystic echinococcosis in Sardinia during the 20th century

At the beginning of the 20th century in Sardinia human Cystic Echinococcosis was considered a highly endemic disease by all the health operators. In the early twenties the number of reported cases was 429, but incidence appeared rising due to increase in availability of data and to improvements in diagnosis. The fall of personal and public hygienic conditions together with the drift from urban to rural areas during the second world war, had in fact facilitated the possibilities of infection, causing a strong growth of surgical cases during the post war years, so that incidence rate remains high and almost unvaried until the end of the eighties. Comparative analysis of young and probably old cysts indicates that this high rate of surgical cases was attributable to treated hepatic cysts in elderly. On the contrary the continuous reduction in the number of young cysts clearly shows a slow but constant decrease of the infection rate.     

Cystic echinococcosis and the Mediterranean Region: a long-lasting association

Cystic echinococcosis (CE) is an important zoonosis in Italy and in the whole Mediterranean Region, as confirmed by the work by Ettore Biocca, whose contributions to the subject are reported in a summarised annex to the bibliography. The contribution to the understanding and control of CE are presented, with special emphasis on the socio-economic impact, on factors affecting the maintenance of CE in the Mediterranean Region, on the epidemiological situation and control measures, on the present status of epidemiological surveillance, on the control problems in normal and emergency situations, on health education and training. Also, the justifications of combined control programmes are discussed, which may be applied only in situations of peace and well-being.     

Cystic echinococcosis: progress and limits in epidemiology and immunodiagnosis

This study discusses the epidemiology and immunodiagnosis of cystic echinococcosis (caused by Echinococcus granulosus). Despite the development of molecular methods to prepare antigens, nowadays there is no standard, highly sensitive, and specific test available for antibody detection in cystic echinococcosis. Furthermore, because serological tests can give only a limited support to clinical findings there is a clear need for new advances in immunodiagnosis of E. granulosus infection.     

Cystic echinococcosis in Greece. Past and present

Cystic echinococcosis is a zoonotic disease with a wide geographical distribution, Greece included, and is considered to be a serious problem for the public health and the livestock economy. Although the disease was widespread in Greece since ancient times, cystic echinococcosis was identified as a serious problem around 1970, and since then national surveillance programmes are running, based on meat inspection and stray dogs management. Ever since, there are official records of the parasite's prevalence in humans and livestock which show a continuous decline. More precisely, human hydatidosis, according to the official records, declines from an annual incidence of 14.8 per 100,000 inhabitants during 1967-1971 to 0.3 in 2008. Late surveys reveal that in Greece the prevalence of echinococcosis was 23-39.2% for sheep, 7.6-14.7% for goats, 0% in cattle and 0.6% in pigs, while further molecular analyses in Southern Greece showed the existence of the genotypes G1 and G3 in sheep and G7 in goats in that area. All data presented demonstrate that the parasite is still present in Greece. Surveillance is nowadays being performed under EU regulations but it is highly important to improve and adopt corrective and preventive measures to avoid animal and human infection.     

Cystic echinococcosis in Italy from the 1950s to present

In Italy the epidemiological pattern of cistic echinococcosis (CE) is incomplete and the information for most regions is out of date, contradictory, and almost exclusively limited to the intermediate hosts. The disease is found most frequently in particular social and economic conditions: widespread use of extensive or semi-extensive sheep farming, illegal slaughtering, and high numbers of sheepdogs and other types of dogs. The highest incidence in sheep is found in Sardinia (70.6-92.8%), Sicily (6.5-36.5%), Basilicata (5-28%), Abruzzo (22%) and Tuscany (47%). It North Italy, it is never higher than 0.5% in slaughtered sheep. No data are available on the biomolecular characterization of the strains of E. granulosus in Italy, apart from Sardinia and recently Lazio. G1 (Sheep strain), G7 (Pig strain) G2 (Tasmanian sheep strain) have been identified in Sardinia and G1 and G3 (Buffalo strain) have been recently isolated in Lazio. In Italy, CE has was also found in buffaloes (2.63-9.8%) and horses (<1%). However, further epidemiological surveys and genotyping study are necessary. The small quantity of up to date information on the diffusion of E. granulosus in dogs (Abruzzo 4%, Sardinia 6-10% and Sicily 19.3%) highlights the need for modern, fast, sensitive and low risk diagnostic methods which would provide a true picture of the pattern of the infection in this host.     

Cystic echinococcosis of the pelvic bone with recurrences: a case report

Hydatid cysts commonly affect the liver and the lung. However, they rarely involve bones with vertebral column. We hereby report a case of a female patient with cystic echinococcosis of the hip bone and ilium. She presented with a long history of frequent recurrences highlighting the dismal prognosis at this rare site. Resection of the hydatid cyst from the sacroiliac region was done with allograft and autograft (rib graft) with lumbosacroiliac fixation. Follow-up of the patient at 6 months showed no detectable abnormality on radiology and the patient was doing well.     

Cystic echinococcosis of lung and heart coupled with repeated echinococcosis of brain--a case report

Echinococcosis is rarely encountered as a cystic brain disease. In this article we are presenting a case of a young woman repeatedly operated due to echinococcosis of lung, heart and brain. Recurrent brain ecchinococcosis developed despite preoperative and postoperative albendazol therapy after first and combined therapy with albendazol and praziquantel after the second brain surgery. The mechanism of recurrence remains unclear (primary infestation, dissemination after spontaneous or intraoperative cyst rupture or new infestation).     

Epidemiology of hydatid disease in Sardinia: a study of fertility of cysts in sheep

Hydatidosis, caused by Echinococcus granulosus, is a cyclozoonotic disease of economic significance in Sardinia. The life-cycle involves stray and sheep dogs as definitive hosts and sheep, pigs, goats and cattle as intermediate hosts. The most important intermediate host is sheep, due to home slaughtering with ready access of the viscera to dogs. This survey was undertaken in 1987 to ascertain the epidemiological significance of sheep in maintaining the life-cycle. A total of 700 (91.3%) of 767 sheep harboured hydatid cysts. The frequency distribution of the number of hydatid cysts was over-dispersed. Of 497 infected sheep, 7.6% had fertile cysts, 75.7% sterile cysts and 16.7% fertile + sterile cysts.     

Haemoglobin phenotypes of the wild European mouflon sheep living on the island of Sardinia

Haemoglobin (Hb) phenotypes have been studied in 100 wild European mouflons living on the island of Sardinia by means of isoelectric focusing (pH 6.7-7.7 range) of the native tetramers, acid-urea-Triton gel-electrophoresis, and reversed-phase HPLC of globin chains. The result indicates the presence of two beta-globin alleles one of which, corresponding to the beta B, being the most common (f = 0.94). None were carriers of the earlier described Hb A. The new Hb was provisionally named Hb M. Severely anaemic mouflons were able to synthesize Hb C at expense of the Hb B alone, thus suggesting structural and physiological homologies between mouflon beta B and sheep beta A globin genes, and between the newly observed beta M allele and the beta B of the domestic Sardinian sheep.     

Cystic echinococcosis in a wild population of the brush-tailed rock-wallaby (Petrogale penicillata), a threatened macropodid

Infection of small macropodids with the larval stage of Echinococcus granulosus can cause fatalities as well as significant pulmonary impairment and other adverse sequelae. The brush-tailed rock-wallaby (Petrogale penicillata) is a small macropodid listed as vulnerable on the IUCN's Red List of Threatened Species. This study used radiographic techniques to determine the prevalence and severity of pulmonary hydatid infection and growth rates of hydatid cysts in a wild population of this macropodid. The overall prevalence was 15.3% (9/59 animals) with 20.0% (8/40 animals) of adults infected. During the study period, the death of at least 1 infected animal was directly attributed to pulmonary hydatidosis. Rapid cyst growth occurred in some animals (up to 43% increase in cyst volume in 3 months). Cyst volume reduced lung capacity by up to 17%. Secondary pulmonary changes were uncommon but, in 1 animal, resulted in reduction in lung capacity by approximately 50%. Infection was associated with a higher blood urea concentration, but no significant differences in other blood variables were detected. These results indicate that hydatid infection may be a significant risk to threatened populations of small macropodids and should be addressed in conservation management plans for these animals.     

Molecular cross-talk in host-parasite relationships: the intriguing immunomodulatory role of Echinococcus antigen B in cystic echinococcosis

Cystic echinococcosis (CE), a zoonosis caused by the development of Echinococcus granulosus tapeworm larvae in the internal organs of ungulates and humans, continues to pose a major public health burden in underdeveloped and industrialised areas worldwide. Research designed to improve parasitic disease control and find out more about parasite biology has already identified a number of E. granulosus antigenic molecules. The major E. granulosus immunomodulant antigen isolated from hydatid fluid is antigen B, a 120kDa polymeric lipoprotein consisting of various 8kDa subunits. By inhibiting elastase activity and neutrophil chemotaxis and eliciting a non-protective Th2 cell response, antigen B helps the parasite evade the human response. In this review, we briefly discuss current information on the molecular characteristics and immunomodulatory properties of E. granulosus antigen B. Besides focusing on findings that provide intriguing insights into the complex interplay between host and parasite, we suggest how this information could extend the current therapeutic options in inflammatory diseases.     

A retrospective analysis of human cystic echinococcosis in Sardinia (Italy), an endemic Mediterranean region,from 2001 to 2005

To assess the current impact of human CE in Sardinia (Italy) and to monitor the changes over time, a survey has been carried out for the period 2001–2005 using hospital inpatient discharge reports (HDR) as information source, supplementing data wherever possible with additional information retrieved directly from medical records. The total of 726 admissions with “Echinococcosis” as primary diagnosis (annual rate of 8.9 per 100,000 inhabitants) concerned 540 CE cases with an annual mean incidence rate of 6.62 per 100,000 inhabitants. Male-to-female ratio was 1.36, suggesting a marked risk associated with traditional male occupations. Age-specific incidence showed increasing rates of clinical CE with age for both genders. The liver was found to be the most common localization, affecting 72% of patients, while pulmonary CE was more frequent in males than in females. CE risk was unevenly distributed in the island. The more pastoral areas had the highest probability of humans becoming infected, with an incidence rate of clinical cases of ~ 14.0 per 100,000 for areas with sheep/inhabitants index of > 6. Compared to the past, incidence rates appear to be decreasing both for pulmonary and hepatic localizations, while there is a reversal of the CE “urbanization” trend resulting in “ruralization”, accompanied by a greater degree of parasite ecological “isolation” and focus-points of infection risk. In spite of this decrease, the cost of hospital care alone (~4 million euros) suggests that the monetary plus non-monetary costs of CE are still very high but not fully recognised.