Post-Treatment Follow-Up Study of Abdominal Cystic Echinococcosis in Tibetan Communities of Northwest Sichuan Province, China

Abstract

BackgroundHuman cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, with the liver as the most frequently affected organ, is known to be highly endemic in Tibetan communities of northwest Sichuan Province. Antiparasitic treatment with albendazole remains the primary choice for the great majority of patients in this resource-poor remote area, though surgery is the most common approach for CE therapy that has the potential to remove cysts and lead to complete cure. The current prospective study aimed to assess the effectiveness of community based use of cyclic albendazole treatment in Tibetan CE cases, and concurrently monitor the changes of serum specific antibody levels during treatment.Methodology/Principal FindingsUltrasonography was applied for diagnosis and follow-up of CE cases after cyclic albendazole treatment in Tibetan communities of Sichuan Province during 2006 to 2008, and serum specific IgG antibody levels against Echinococcus granulosus recombinant antigen B in ELISA was concurrently monitored in these cases. A total of 196 CE cases were identified by ultrasound, of which 37 (18.9%) showed evidence of spontaneous healing/involution of hepatic cyst(s) with CE4 or CE5 presentations. Of 49 enrolled CE cases for treatment follow-up, 32.7% (16) were considered to be cured based on B-ultrasound after 6 months to 30 months regular albendazole treatment, 49.0% (24) were improved, 14.3% (7) remained unchanged, and 4.1% (2) became aggravated. In general, patients with CE2 type cysts (daughter cysts present) needed a longer treatment course for cure (26.4 months), compared to cases with CE1 (univesicular cysts) (20.4 months) or CE3 type (detached cyst membrane or partial degeneration of daughter cysts) (9 months). In addition, the curative duration was longer in patients with large (>10 cm) cysts (22.3 months), compared to cases with medium (5–10 cm) cysts (17.3 months) or patients with small (<5 cm) cysts (6 months). At diagnosis, seven (53.8%) of 13 cases with CE1 type cysts without any previous intervention showed negative specific IgG antibody response to E. granulosus recombinant antigen B (rAgB). However, following 3 months to 18 months albendazole therapy, six of these 7 initially seronegative CE1 cases sero-converted to be specific IgG antibody positive, and concurrently ultrasound scan showed that cysts changed to CE3a from CE1 type in all the six CE cases. Two major profiles of serum specific IgG antibody dynamics during albendazole treatment were apparent in CE cases: (i) presenting as initial elevation followed by subsequent decline, or (ii) a persistent decline. Despite a decline, however, specific antibody levels remained positive in most improved or cured CE cases.ConclusionsThis was the first attempt to follow up community-screened cystic echinococcosis patients after albendazole therapy using ultrasonography and serology in an endemic Tibetan region. Cyclic albendazole treatment proved to be effective in the great majority of CE cases in this resource-poor area, b...

Factors Influencing the Serological Response in Hepatic Echinococcus granulosus Infection

“…The stage of the cyst is the variable most often investigated in correlation with serology results, with a consensus finding that patients with CE1 and CE4-CE5 (hepatic) cysts are seronegative in a high percentage of cases (30-58% and 50-87%, respectively), while rates of negativity are lower in the presence of CE2 and CE3 cysts (5-20%). 10,[12][13][14] When the variables associated with serology results were investigated in more detail, serodiagnosis performance correlated with stage, number (single versus multiple), location (liver versus lungs), and size (< or > than 15 cm) of cysts; presence of complications; and collection of serum after treatment. 10,11,13,15 Although in the majority of cases of hepatic CE the combined use of imaging and serology allows for a reliable diagnosis, in some instances they are inconclusive, and differential diagnosis with other lesions may be challenging.…”

“…10,[12][13][14] When the variables associated with serology results were investigated in more detail, serodiagnosis performance correlated with stage, number (single versus multiple), location (liver versus lungs), and size (< or > than 15 cm) of cysts; presence of complications; and collection of serum after treatment. 10,11,13,15 Although in the majority of cases of hepatic CE the combined use of imaging and serology allows for a reliable diagnosis, in some instances they are inconclusive, and differential diagnosis with other lesions may be challenging. This is particularly true in the case of small CE1 and old inactive CE4-CE5 cysts that may lack clear pathognomonic signs of echinococcal etiology on US and are serology negative in a high proportion of cases.…”

Evaluation of Patients with Cystic Echinococcosis

“…Spleen (12) 77.7 (7) Splenectomy (6) Cystostomy and drainage (1) Bone (5) 100 (5) Debridement (3) Partial cystectomy and drainage (1) Mesentery (7) 85.1 (6) Small bowel resection (1) Cystectomy (5) Omentum (6) 100 (6) Cystectomy (6) Muscle (3) 100 (3) Cystectomy (3) Brain (2) 100 (2) Cystectomy (2) Adrenal (1) 100 (1) Cystectomy (1) Bladder (1) 100 (1) Cystectomy (1) Pancreas (1) 100 (1) Cystectomy (1) Turkiye Parazitol Derg 2017; 41: [28][29][30][31][32][33] Türkoğlu at al. Cystic Echinococcosis and lack of disease control programs (1,6,7).…”

“…Another alternative is mebendazole, which is given at a daily dose of 40-50 mg/kg in three divided doses (6,26). It has been reported that the treatment response rate of 30% was achieved when patients were treated for 3-6 months, while the prolongation of treatment to up to 18-30 months accomplished a 32.7% decrease in the number of cysts and 49% cystic degeneration, which amounted to an overall response rate of 81% (26,29). The most important reason why albendazole treatment does not have the desired level of success is its poor absorptive capacity.…”

The genome of the hydatid tapeworm Echinococcus granulosus

“…The larval (metacestode) stage causes hydatidosis (cystic hydatid disease; cystic echinococcosis), a chronic cyst-forming disease in the intermediate (human) host. Currently, up to 3 million people are infected with E. granulosus 2,3 , and, in some areas, 10% of the population has detectable hydatid cysts by abdominal ultrasound and chest X-ray 4,5 .…”