[Epidemiological and clinical features of newly reported advanced schistosomiasis cases in Sichuan Province from 2011 to 2022]

OBJECTIVE

To analyze the epidemiological characteristics of newly reported advanced schistosomiasis cases in Sichuan Province, so as to provide the evidence for analyzing the causes and formulating targeted control measures of newly reported advanced schistosomiasis cases.

METHODS

Individual case investigation forms for advanced schistosomiasis cases were collected from the Sichuan Provincial Epidemic Annual Report System from 2011 to 2022, and patients' demographics, previous medical history and liver parenchymal grading were retrieved. All advanced schistosomiasis cases' medical records were reviewed, and the subtypes of schistosomiasis-endemic villages where the cases' household registration were, floating population, survival and death and time of death were collected.

RESULTS

A total of 321 newly reported advanced schistosomiasis cases were found in Sichuan Province from 2011 to 2022, with a male to female ratio of 0.99 to 1. There were 274 cases at ages of over 50 years (85.4%), with the highest proportion seen at ages of 60 to 69 years (87 cases, 27.1%), and splenomegaly was the most common type (180 cases, 56.1%), with no dwarfism type detected. The highest number of cases was reported in 2011 (78 cases), followed by in 2022 (74 cases), and the highest number of cases were reported in Meishan City (199 cases, 62.0%), Dongpo District (131 cases, 40.8%), and hilly subtype areas (136 cases, 42.4%). As of the end of 2022, there were 111 deaths due to advanced schistosomiasis, with the highest number of deaths seen in 2018 (25 deaths), and the highest mortality was seen among patients with the ascites type (41.2%). There were 47 (37.3%), 40 (59.5%) and 4 (23.5%) cases with grade III liver parenchyma among patients with splenomegaly, ascites, and colonic proliferation types, respectively, and there was a significant difference in the grading of III liver parenchyma among three types of patients (H = 12.092, P < 0.05), with more severe liver parenchyma injuries seen among patients with the ascites type than among those with splenomegaly and colonic proliferation type (Z = 24.262 and 44.738, both Padjusted values < 0.05).

CONCLUSIONS

There have been newly reported advanced schistosomiasis cases in Sichuan Province during recent years, and patients with the ascites type should be given a high priority among advanced schistosomiasis cases in Sichuan Province. Intensified clue surveys are needed for early identification and treatment of advanced schistosomiasis cases, so as to increase the survival rate and improve the quality of life.

Genetic evolutionary analysis of soybean mosaic virus populations from three geographic locations in China based on the P1 and CP genes

Soybean mosaic virus (SMV) is one of the major pathogens causing serious soybean losses. Little is known about the genetic structure and evolutionary biology of the SMV population in southwestern China. In this study, 29 SMV isolates were obtained from Sichuan Province, and the genomic regions encoding the first protein (P1) and coat protein (CP) were sequenced. Combined with SMV isolates from the southeastern and northeastern regions of China, the genetic and molecular evolution of SMV was studied. Recombination analysis revealed that intraspecific and interspecific recombination had occurred in the SMV population. A phylogenetic tree based on the P1 gene reflected the geographic origin of the non-interspecific recombinant SMV (SMV-NI), while a tree based on the CP gene did not. Though frequent gene flow of the SMV-NI populations was found between the southeastern and northeastern populations, the southwestern population was relatively independent. Genetic differentiation was significant between the SMV interspecific recombinant (SMV-RI) and the non-interspecific recombinant (SMV-NI) populations. It was interesting to note that there was an almost identical recombination breakpoint in SMV-RI and Watermelon mosaic virus (WMV). Population dynamics showed that SMV-RI might be in an expanding state, while the SMV-NI population is relatively stable.