Survey of echinococcoses in southeastern Qinghai Province, China, and serodiagnostic insights of recombinant Echinococcus granulosus antigen B isoforms

Abstract

Background: Echinococcoses, caused by metacestodes of Echinococcus granulosus (cystic echinococcosis; CE) and E. multilocularis (alveolar echinococcosis; AE), represent major emerging parasitic diseases. These enzootic helminthiases invoke significant public health concerns and social burdens in endemic areas. The diseases are prevalent in the Qinghai-Tibetan Plateau, China, while community-based epidemiological studies have been scarcely reported. We surveyed echinococcosis patients in the southeastern Qinghai Province, China, to better understand the concurrent epidemiological situation in this area. Methods: During July and August of 2013 and 2014, we screened echinococcosis patients at Yushu and Golog Prefectures, Qinghai Province, China, in a diagnostic campaign. A total of 2856 people (male:female ratio, 1:1.12; mean age, 34.6 years; age range, 6-88 years) were ultrasonographically examined for the presence of hepatic echinococcal cysts. We also collected serum samples from patients and analyzed antibody reactivity against recombinant forms of diverse E. granulosus antigen Bs (rEgAgB1-5) by enzyme-linked immunosorbent assay. Results: We detected 134 patients whose imaging scans were compatible with CE (115 cases) and AE (20 patients). One patient might have been infected with both CE and AE. The overall incidence was 4.7% (CE, 4.0%; AE, 0.7%). A large proportion (67.5%) of CE patients was diagnosed at active and transitional CE1-CE3 stages in their late 30s. The AE cases were generally detected at advanced stage in patients at early 20s (60%). Analysis of the receiver operating characteristic curve and Youden's index indicated that rEgAgB2 was the most promising biomarker, followed by rEgAgB3 and rEgAgB1. Overall, sensitivity and specificity of rEgAgB1-3 were 84.5-92.7% and 91.9-94.6%, respectively. rEgAgB4 and 5 showed low sensitivity with high cross-reactivity. Conclusions: Our results strongly suggest that disability-adjusted life years related to echinococcoses in Qinghai-Tibetan areas might be more serious than previously considered. Control and prevention strategy against CE and AE are highly required in these areas. In addition to ultrasonography, serological tests might provide supportive data. However, serological data should be carefully interpreted for differential diagnosis, especially in areas where both CE and AE are co-endemic.

Prevalence of human alveolar echinococcosis in China: a systematic review and meta-analysis

“…3). However, it is necessary to keep monitoring levels through continuous surveillance and investigation in the future [8]. Additionally, the meta-regression analysis suggested that there was a negative correlation between the period in which the studies were conducted and the HAE prevalence, which corroborates the variation trend of HAE prevalence.…”

“…HAE has become a global threat to public health [ 6 – 8 ]. There are 18,235 new cases of HAE every year in the world, with the disease burden reaching 666,433 disability-adjusted life years (DALYs) [ 9 , 10 ].…”

Prevalence of human alveolar echinococcosis in China: a systematic review and meta-analysis

“…However, it is necessary to keep monitoring levels through continuous surveillance and investigation in the future [8]. Additionally, the meta-regression analysis suggested that there was a negative correlation between the period in which the studies were conducted and the HAE prevalence, which corroborates the variation trend of HAE prevalence.…”

Prevalence of human alveolar echinococcosis in China: a systematic review and meta-analysis

“…3). However, it is necessary to keep monitoring levels through continuous surveillance and investigation in the future [8]. Additionally, the metaregression analysis suggested that there was a negative correlation between the time period during which the studies were conducted and the HAE prevalence, which corroborates the variation trend of HAE prevalence.…”