Avian trichomoniasis caused by Trichomonas gallinae is a serious protozoan disease worldwide. The domestic pigeon (Columba livia domestica) is the main host for T. gallinae and plays an important role in the spread of the disease. Based on the internal transcribed spacers of nuclear ribosomal DNA of this parasite, a pair of primers (TgF2/TgR2) was designed and used to develop a PCR assay for the diagnosis of T. gallinae infection in domestic pigeons. This approach allowed the identification of T. gallinae, and no amplicons were produced when using DNA from other common avian pathogens. The minimum amount of DNA detectable by the specific PCR assay developed in this study was 15 pg. Clinical samples from Guangzhou, China, were examined using this PCR assay and a standard microscopy method, and their molecular characteristics were determined by phylogenetic analysis. All of the T. gallinae-positive samples detected by microscopic examination were also detected as positive by the PCR assay. Most of the samples identified as negative by microscopic examination were detected as T. gallinae positive by the PCR assay and were confirmed by sequencing. The positive samples of T. gallinae collected from Guangzhou, China, were identified as T. gallinae genotype B by sequencing and phylogenetic analyses, providing relevant data for studying the ecology and population genetic structures of trichomonads and for the prevention and control of the diseases they cause.
China* ; Columbidae* ; Diagnosis ; DNA ; DNA, Ribosomal ; Ecology ; Genetic Structures ; Genotype ; Methods ; Microscopy ; Parasites ; Polymerase Chain Reaction* ; Trichomonas*

Objective To grasp the distribution status of Oncomelania hupensis snails in Poyang Lake area,so as to provide the evidence for formulating and adjusting the schistosomiasis prevention and control strategy in lake areas. Methods The vec-tor grid was created and sampled randomly by 200 m × 200 m in the spatial database of grassland,and the distribution of snails was investigated in the selected grid by using the method of mechanical sampling by 50 m × 50 m. At the same time,the eleva-tion of investigation points was extracted based on the topographic map of Poyang Lake. Results Totally 949 and 210 investiga-tion points were collected from the south and north of Poyang Lake areas,accounting for 3.04%and 3.21%of all the investiga-tion points in the respective region. The number of investigation points,the appearance rate of snail frame,and the average den-sity of alive snails were 15231,8.15%,and 0.463/0.1 m2,respectively. The elevation of snail distribution area of the south and north Poyang Lake areas were 11-16 m and 9-16 m respectively. The elevation of concentrated snail belts of the south Poyang Lake area were 12-13 m and 15-16 m,and the elevation of concentrated snail belts of the north Poyang Lake area was 12-14 m. Conclusions The distribution of snails is in the range of 9-16 m. The suitable habitats of snail breeding are moving from the south Poyang Lake area to the north Poyang Lake area,and from high elevation to low elevation. In the future,the schistosomia-sis prevention and control measures could be formulated based on the geographical characteristics of current snail distribution in order to consolidate the achievements of schistosomiasis control.