Degree of calcification and cyst activity in hepatic cystic echinococcosis in humans.

To evaluate the relationship between cyst activity and calcification degree in cystic echinococcosis (CE) in humans, 99 hepatic cysts at successive stages of involution, surgically excised from 72 Sardinian patients, have been analyzed. Cysts were classified into 4 groups according to calcification extent: CALC 0 (no calcification); CALC 1 (scattered punctate calcifications); CALC 2 (large coarse segmental/partial calcifications); CALC 3 (complete or nearly complete circumferential ring of calcification up to thick wall of osseous consistency/calcified content of cyst). In addition the possible correlation with antibody response has been explored analyzing IgG1, IgG4 and IgE produced against somatic PSCAg. Results showed that calcification is not restricted to the inactive WHO cyst types CE4 and CE5, but occurs to a varying extent in all morphotypes of metacestode, from active classic unilocular or multivesicular cysts to the more complicated and highly degenerate stages, where cyst wall appears massively calcified. Prevalence of calcification increases with progression of cyst degenerative process, but is not synonymous with parasite inactivity and can be misleading as signs of calcification may coexist with still metabolically active cysts. On the contrary, detection of entirely firmly solidified content seems a reliable indication of cyst inactivity. IgG4 is the dominant isotype associated particularly with the evolutive phase. Positive rates and OD levels, higher in active vs inactive stages, are stable or increase slightly in weakly and moderately calcified cysts (CALC 1/CALC 2), compared to non-calcified ones (CALC 0), strongly decreasing in highly calcified forms (CALC 3). In conclusion, evaluation of calcification extent may be pertinent for staging CE, and immunological tests, particularly for IgG4, and IgE may help to better define cyst activity.

A study of morphological aspects of cystic echinococcosis in sheep in Sardinia.

We have investigated the morphological and structural aspects of hydatid cysts recovered from sheep raised in southern Sardinia during two surveys conducted over the 20 years since the last control attempt at the end of the 1980s. In the first study carried out during 1995-1997, a few years after the last control attempt, a total of 10,334 cysts were examined, recovered from 1029 infected sheep out of a total of 1375 inspected (prevalence 74.84%). In the second survey, conducted ten years later during the period 2005-2010 in the absence of specific control measures, a total of 6249 cysts were recovered from 916 parasitized sheep out of the 1414 examined (prevalence 64.78%). Cysts were grouped into 5 different types: "Unilocular", "Multisepted", "Calcified", "Caseous", "Hyperlaminated". Unilocular: fertile, consist of a single fluid-filled cavity; multisepted: generally sterile, fluid filled, with cavity divided into spheroidal chambers (3-dozen); calcified: sterile, small, with internal chambers almost virtual due to the thickening of internal septa; caseous: sterile, the cavity filled with a thick yellowish matrix; hyperlaminated: sterile, with a virtual cavity filled with extensively folded and overlapping sheets of hyperproduced laminated tissue. A thorough knowledge and the precise characterization of each type of lesion, making it possible to establish detailed parameters for cyst classification, appears very useful for the harmonization of data collection. From a surveillance and control perspective it is proposed that, in addition to other relevant epidemiological information, data from meat inspection be further improved, including morpho-functional indications about cyst type.

Cystic echinococcosis in sheep in Sardinia. Changing pattern and present status.

The epidemiological status of cystic echinococcosis (CE) in sheep in Sardinia over the 20 years since the last control attempt at the end of the 1980s has been assessed, comparing the results of two surveys carried out in abattoirs in southern Sardinia. In the first, conducted in 1995-1997 (5-7 years after the last control effort), CE prevalence of about 75% was observed in the 1375 sheep sampled, with intensity of 10.0 and mean abundance of 7.5. The most affected organ was the liver, whereas a large percentage of infected animals presented cysts in both the liver and lung. Overall, about 26% of parasitized sheep were found to be heavily infected and 12.15% of infected animals harboured fertile cysts. In the second survey, carried out ten years after the first, during the period 2005-2010 in absence of specific control measures, a total of 1414 sheep were examined. CE prevalence was 65%, 78% in the most rural Oristano province and 58% in the most "urbanised" province of Cagliari. Frequency of sheep infected in both the liver and lung had decreased slightly compared to the first survey, particularly in the Cagliari province, as had intensity and mean abundance, though to a lesser extent in the Oristano province. 14.6% of parasitized sheep were heavily infected, showing a general decline over the 10 years between the two surveys, particularly in the Cagliari area where the figure had more than halved. Conversely, about 14% of infected sheep hosted at least 1 fertile cyst, a slight increase compared to the 1st survey. Finally, the trend of CE transmission in Sardinian sheep according to surveys carried out from 1952 to 2010 has been analysed and the results are discussed in the light of the significant socio-economic and structural transformations that have actually modified the zoonosis scenario on the island.