Background: There are limited studies on the molecular profile of thalassemia in Hainan, the free trade island in China. Our aim was to reveal the prevalence and molecular mutation spectrum of thalassemia in different ethnic groups and regions of Hainan through a large sample study for the first time.Methods: A total of 231,596 individuals from 19 cities and counties in Hainan were screened by hematological parameter analysis, and further genetic analysis was performed on individuals with MCV less than 82 fL.Results: Totally, 31,780 (13.72%) subjects were diagnosed as thalassemia carriers. The overall prevalence of α-thalassemia, β-thalassemia, and α+β-thalassemia were 11.04%, 1.48%, and 1.20%, respectively. We further analyzed the molecular profiles of thalassemia in various ethnic groups and mainly compared the difference between Han and Li. The results showed that the frequency of thalassemia in the Li population (47.03%) was much higher than that in Han (9.37%). Except for β-thalassemia (1.31% of Li vs. 1.47% of Han), the frequencies of α-thalassemia (39.59% of Li vs. 7.35% of Han) and α+β-thalassemia (6.13% of Li vs. 0.56% of Han) in the Li were obviously higher than those in Han. The high-frequent genotypes of α-thalassemia in Han were αα/--^SEA (25.55%), -α^3.7/αα (22.17%), -α^4.2/αα (21.59%), α^WSα/αα (8.93%), and -α^3.7/-α^4.2 (4.17%) and those of Li were -α^4.2/αα (17.24%), -α^3.7/αα (17.16%), -α^3.7/-α^4.2 (15.09%), α^WSα/αα (9.69%), and α^WSα/-α^3.7 (8.06%), respectively. The αα/--^SEA was the highest genotype of α-thalassemia in Han but only accounted for 1.87% in Li. For β-thalassemia, the top three high-frequent genotypes in both Han and Li were β^{CD41/42(-TTCT)}/β^N, β^-28(A>G)/β^N, and β^{IVS-Ⅱ-654(C>T)}/β^N, but the frequency of β^{CD41/42(-TTCT)}/β^N in Li (90.96%) was much higher than that in Han (56.32%) and the data reported in other provinces of China. Additionally, the prevalence of thalassemia ranged from 8.16% to 34.35% in Hainan, Wuzhishan, Baoting, Qiongzhong, and Baisha have a higher prevalence than other areas.Conclusion: Our study revealed the characteristics of ethnic and regional differences in the prevalence of thalassemia in the childbearing age population of Hainan for the first time, indicating that the prevalence of thalassemia among Li nationality is the highest in China. Those findings will be useful for genetic counseling and the prevention of thalassemia.

Scrub typhus, caused by mite-borne Orientia tsutsugamushi (O. tsutsugamushi), is a major febrile disease in the Asia-Pacific region. The DNA load of O. tsutsugamushi in the blood was previously found to be significantly higher in patients with fatal disease than those with non-fatal disease and correlated with the duration of illness, presence of eschar, and hepatic enzyme levels. In this prospective observation study, we analyzed the association of bacterial DNA load with clinical features, disease severity, and genotype using real-time PCR targeting the 56 kDa TSA gene of O. tsutsugamushi in the blood samples of 117 surviving patients with scrub typhus who had not received appropriate antibiotic treatment. The median O. tsutsugamushi DNA load was 3.11×10³ copies/mL (range, 44 to 3.3×10⁶ copies/mL). The severity of patients was categorized as mild, moderate, and severe based on the number of dysfunctional organs, and no significant difference in O. tsutsugamushi DNA load was found among these groups. Patients infected with the Karp group showed a significantly higher O. tsutsugamushi DNA load than those in the Gilliam (P < 0.05) and TA763 (P < 0.01) groups. Patients belonging to the Li ethnic group showed a significantly higher DNA load than those in the Han ethnic groups. The blood bacterial DNA load of patients showed no significant difference between groups divided by gender, age, with or without eschar, or the season of disease onset. The highest body temperature recorded during fever onset was positively correlated with O. tsutsugamushi DNA load (ρ = 0.272, P  = 0.022). Correlation analyses indicated that the serum total bilirubin level was positively correlated with O. tsutsugamushi DNA load. In conclusion, the findings in this study demonstrated the association of DNA load of O. tsutsugamushi with the severity and genotype in patients with scrub typhus in Hainan, China.

Background: Hainan has one of the high incidences of thalassemia in China, but the epidemiological data in the whole province has not been reported yet. The objective of our study was to reveal the true prevalence and molecular mutation spectrum of thalassemia in the population of Hainan who are of childbearing age.Methods: We screened 166,936 individuals from 19 cities and counties in Hainan by hematological parameters analysis, and further conducted genetic analysis for individuals whose MCV was less than 82fL.Results: In total, 21,619 (12.95%) subjects were diagnosed as thalassemia carriers or patients. The overall prevalence of α‐thalassemia, β‐thalassemia, and α+β‐thalassemia were 10.39%, 1.38%, and 1.18%, respectively. Eleven α‐thalassemia mutations and sixteen β‐thalassemia mutations were identified. The high‐frequent genotypes of α‐thalassemia were ‐α^3.7/αα (19.70%), ‐α^4.2/αα (19.39%), αα/‐‐^SEA (15.60%), α^WSα/αα (9.24%), and ‐α^3.7/‐α^4.2 (8.90%), and those of β‐thalassemia were β^{CD41/42(−TTCT)}/β^N (58.92%), β^−28(A>G)/β^N (16.05%), β^{IVS−Ⅱ−654(C>T)}/β^N (8.42%), β^CD71/72(+A)/β^N (6.03%), β^CD17(A>T)/β^N (5.47%), and β^{CD26 (GAG>AAG)}/β^N (2.69%). In addition, the frequencies and hematological profiles of many rare mutations of α‐ [Fusion, HKαα, αααanti^4.2, IVS‐II‐55 (T>G), IVS‐II‐119 (−G,+CTCGGCCC)] and β‐globin genes [−50 (G>A), IVS‐Ⅱ‐81 (C>T)] in Hainan were reported for the first time.Conclusion: Our study revealed the high prevalence and extensive molecular spectrum of thalassemia in childbearing age population of Hainan, suggesting thalassemia in Hainan ranks second in prevalence among all regions in China. The findings will be useful for genetic counseling and prevention of thalassemia.