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.

Coccidiosis caused by protozoan parasites of the genus Eimeria has a severe economic impact on commercial production worldwide. Micronemes of Eimeria play important roles in invading intestinal cell processes. In this study, the DNA vaccine expressing Eimeria tenella microneme protein 3 (EtMIC3) was constructed to evaluate its immune protective effect against E. tenella infection in chickens. The results demonstrated that chickens immunized with pVAX-EtMIC3 produced strong immune responses in the body, as shown by significant lymphocyte proliferation, cytokine production, and antibody responses. The average body weight gains of chickens in all the vaccinated groups were higher than those of non-vaccinated and challenged groups. In general, oocyst shedding was reduced, and bloody feces and gut lesion scores decreased. In addition, the survival rate of the immunized chickens increased compared to that of the unvaccinated and challenged control chickens. In summary, this study indicated that pVAX-EtMIC3 could induce protective immune effects against coccidiosis and that EtMIC3 is a potential vaccine candidate against coccidiosis.

The prevalence of chlamydiosis in pet dogs was surveyed in Shenzhen, Guangdong Province, China. A total of 442 serum samples were collected from three districts of Shenzhen, namely the Futian, Nanshan, and Luohu Districts, and assayed for Chlamydiaceae antibodies by indirect haemagglutination assay. The results showed that the mean positive rate was 6.11%, and the positive rate for the Futian District was the highest (9.52%), followed by the Nanshan District (7.08%), and the Luohu District (4.02%). The positive rate for male dogs was 6.08%, and for female dogs 6.16%. Out of all the 38 breeds of dogs examined, 14 breeds were positive. The positive rate for the Cocker Spaniel dog was the highest (14.2%), followed by the Pekinese dog