[Prevalence of human soil-borne nematode infections in Yunnan Province: a cross-sectional study in 2015].

OBJECTIVE: To investigate the current prevalence of human soil-borne nematode infections in Yunnan province, so as to provide the scientific evidence for formulating the soil-borne nematodiasis control strategy in the province. METHODS: In 2015, a total of 20 survey sites were sampled in 10 counties (cities) of Yunnan Province using the stratified cluster random sampling method. Stool samples were collected from all local permanent residents at ages of one year and older in each survey site, and the soil-borne nematode eggs were identified using the modified Kato-Katz technique and the egg number was counted. In addition, the hookworm species was identified using the filter-paperculture method, and Enterobius vermicularis eggs were detected using the cellophane tape method in children at ages of 3 to 6 years. RESULTS: A total of 5 067 residents received stool examinations, and 950 residents were detected with soil-borne nematode infections, with an overall prevalence rate of 18.75%. The prevalence of Ascaris lumbricoides, Trichuris trichura and hookworm was 7.52%, 8.47% and 9.02%, respectively. Among 446 children detected using the cellophane tape method, 5 children were detected with E. vermicularis infections. Among the 160 residents with hookworm infections, there were 139 residents with Necator americanus infections (86.88%), 16 with A. duodenale infections (10.00%) and 5 with mixed infections (3.12%). Mild A. lumbricoides (67.98%, 259/381), T. trichura (88.58%, 380/429) and hookworm infections (94.53%, 432/457) were predominant. Among the four ecological zones, the highest prevalence of human soilborne nematode infections was found in the East Tibet-South Sichuan Ecological Zone (31.79%), and among the 10 survey counties (cities), the greatest prevalence was seen in Gongshan Derung and Nu Autonomous County (50.13%), while the lowest prevalence was found in Ninglang Yi Autonomous County (0.40%). The prevalence of human soil-borne nematode infections was 5.67% (43/759), 26.67% (610/2 287) and 14.70% (297/2 021) in high-, moderate- and low-economic-level regions, respectively. There were no significant differences in the prevalence of human soil-borne nematode infections in terms of ecological regions, survey counties (cities) or economic development levels (χ2 = 342.20, 814.60 and 201.34, all P < 0.05). There was no significantdifference in the prevalence of human soil-borne nematode infections between male (18.21%, 441/2 422) and female residents (19.24%, 509/2 645) (χ2 = 0.89, P > 0.05), and soil-borne nematode infections were detected in residents at all age groups, with the greatest prevalence found in residents at ages of 1 to 9 years (25.88%). In addition, the highest prevalence of soil-borne nematode infections was seen in residents with the Dulong Ethnic Minority (82.09%), in preschool children (25.06%) and in illiterate residents (24.80%), and there was no age-, ethnicity-, occupation- or education level-specific prevalence of soil-borne nematode infections detected (χ2 = 46.50, 1 016.96, 36.33 and 52.43, all P < 0.05). CONCLUSIONS: The prevalence of human soil-borne nematode infections remains high in Yunnan Province. The management of soil-borne nematodiasis requires to be reinforced among low-age children, farmers, old people and residents with low educations levels or ethnic groups.

Host Status of Selected Crops to Meloidogyne chitwoodi.

Various crops were tested in greenhouse and field trials for their potential utility in the rotation sequence in the potato cropping system in Meloidogyne chitwoodi-infested soils of the Klamath Basin in northeastern California and southern Oregon. Two Solarium accessions from the International Potato Center in Peru were potential sources of resistance to M. chitwoodi. Cultivars of barley, oat, rye, wheat, and white lupine were maintenance hosts, supporting the nematode population at its current level without substantial increase or decline. Poor to nonhosts to race 1 of the nematode included cultivars of alfalfa, amaranth, oilseed radish, oilseed rape, and safflower. These crops have potential for inclusion in the cropping system but are subject to various constraints, including frost sensitivity and availability of markets. Sugarbeet, a new crop in the area, is a maintenance or better host of M. chitwoodi. Potato, tomato, and sunflower are excellent hosts.

Zellweger syndrome: report of one case.

Zellweger syndrome is a fatal autosomal-recessive hereditary disease characterized by the absence of peroxisomes in liver and kidneys. The absence of peroxisomes results in impairment of many metabolic pathways, especially beta-oxidation of very long chain fatty acids (VLCFAs). We report a case of a three-month-old male infant with facial dysmorphism, hypotonia, psychomotor retardation, and hepatomegaly. He had an elder brother with the same facial features and hypotonia who died of hepatic failure at four months of age. Biochemical studies revealed elevation of blood pipecolic acid and VLCFAs, compatible with peroxisomal disorder. Electron microscopy of liver biopsy revealed absence of peroxisomes. Zellweger syndrome was diagnosed. Because this syndrome is usually fatal in early life, genetic counseling and prenatal diagnosis are crucial.