Abstract:

Objective To investigate the current status of intestinal parasitic infections in areas inhabited by Bulang nationality in Yunnan Province, and to provide a scientific basis for formulating prevention and control strategies. Methods In 2015 and 2023, the survey was carried out in Bulang Township, Menghai County, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province using cluster random sampling, and the survey subjects were permanent residents of all ages who lived for more than 6 months. The fecal samples and information of survey subjects such as gender, age and education level were collected. The modified Kato-Katz thick smear method (two slides per sample) was used to detect and count the eggs of intestinal worms, and each fecal sample was cultured to detect the hookworm used tube-filter paper culture method. Intestinal protozoa were detected by iodine staining smear method. Eggs, cysts or hookworms detected during fecal examination were judged to be intestinal parasitic infections, and the intensity of soil-transmitted nematode was determined. The population data of the two surveys were combined as the standard population to standardize the infection rate. The chi-square test was used for the comparison of the standardized infection rate. Results In 2015, a total of 800 people were surveyed in areas inhabited by Bulang nationality in Yunnan Province, and 564 people were positive for parasitic infection, with a standardized infection rate of 71.09%. In 2023, a total of 1 128 people were surveyed, and 203 people were positive for parasitic infection, with a standardized infection rate of 17.84%. The standardized infection rate of parasites in 2023 was lower than that in 2015 (χ² = 1 107.636, P < 0.01). The standardized infection rates of intestinal worms in 2023 was 12.17%, which was lower than that in 2015 (69.36%) (χ² = 1 304.222, P < 0.01). The standardized infection rates of Ascaris lumbricoides, hookworm and Trichuris trichura in 2023 (2.78%, 6.76% and 3.13%) were lower than those in 2015 (54.67%, 25.86% and 30.22%) (χ² = 1 266.428, 258.666, 510.527, all P < 0.01). In 2015 and 2023, the intensity of A. lumbricoides, hookworm and T. trichura were mainly mild infected. In 2015 and 2023, the standardized infection rates of intestinal protozoa were 5.21% and 6.39%, respectively, with no significant difference (χ² = 2.518, P > 0.05). The standardized infection rate of Blastocystis hominis in 2023 (3.11%) was higher than that in 2015 (1.04%) (χ² = 20.424, P < 0.01). The standardized infection rates of females and males were 75.47% and 66.18% in 2015 and 20.53% and 14.92% in 2023, respectively. The standardized infection rates of females in 2015 and 2023 were higher than those in males (χ² = 20.035, 10.416, both P < 0.01). The 20-29 year age group had the highest standardized infection rate of 23.53% in 2023, and there were statistically significant differences between the age groups (χ² = 14.683, P < 0.05); but no significant difference in 2015 (χ² = 13.211, P > 0.05). There was a significant difference in the standardized infection rate among the different education levels in 2015 (χ² = 21.108, P < 0.01), but no significant difference in 2023 (χ² = 2.007, P > 0.05). The standardized infection rate of Bulang nationality was 71.03%, which was higher than that of other nationalities (1.39%) (χ² = 155.480, P < 0.01) in 2015, and there was no significant difference between the standardized infection rate of Bulang nationality (17.73%) and other nationalities (20.83%) in 2023 (χ² = 0.456, P > 0.05). Conclusion In 2023, the infection rate of intestinal parasites in areas inhabited by Bulang nationality in Yunnan Province decreased significantly compared with 2015. The infection rate of intestinal worms decreased significantly, and the infection rate of intestinal protozoa increased.

Key words: Intestinal parasites, Yunnan Province, Bulang nationality, Infection rate