Morphology and Molecular Phylogeny of Raillietina spp. (Cestoda: Cyclophyllidea: Davaineidae) from Domestic Chickens in Thailand

Raillietina species are prevalent in domestic chickens (Gallus gallus domesticus) in Phayao province, northern Thailand. Their infection may cause disease and death, which affects the public health and economic situation in chicken farms. The identification of Raillietina has been based on morphology and molecular analysis. In this study, morphological observations using light (LM) and scanning electron microscopies (SEM) coupled with molecular analysis of the internal transcribed spacer 2 (ITS2) region and the nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) gene were employed for precise identification and phylogenetic relationship studies of Raillietina spp. Four Raillietina species, including R. echinobothrida, R. tetragona, R. cesticillus, and Raillietina sp., were recovered in domestic chickens from 4 districts in Phayao province, Thailand. LM and SEM observations revealed differences in the morphology of the scolex, position of the genital pore, number of eggs per egg capsule, and rostellar opening surface structures in all 4 species. Phylogenetic relationships were found among the phylogenetic trees obtained by the maximum likelihood and distance-based neighbor-joining methods. ITS2 and ND1 sequence data recorded from Raillietina sp. appeared to be monophyletic. The query sequences of R. echinobothrida, R. tetragona, R. cesticillus, and Raillietina sp. were separated according to the different morphological characters. This study confirmed that morphological studies combined with molecular analyses can differentiate related species within the genus Raillietina in Thailand.

A Study on the Seasonal Prevalence of Raillietina Tetragona in Domestic Chick (Gallus Domesticus) from Warangal Region of Andhra Pradesh.

The prevalence of Raillietina tetragona, a helminth parasite was examined in domestic chick for a period of two annual cycles to determine the effects of seasonal variation on intensity and incidence of infection. The results show that the infection was more during summer followed by rainy and winter seasons. The infection was single or in association with other helminth parasites like Raillietina echinobothrida, Raillietina cesticillus and Ascardia galli. The results are discussed in relation to seasonal variation. The results were analysed by student t-test (P<0.05).

Two cestode species in Brazilian turkeys, meleagris gallopavo (Galliformes, Phasianidae): pathology induced by hymenolepis cantaniana and occurrence of raillietina tetragona

Duas especies de cestóides em perus, Meleagris gallopavo (Galliformes, Phasianidae), no Brazil: patologia induzida por Hymenolepis cantaniana e ocorência de Raillietina tetragona. A patologia induzida em perus pelo cestóide H. cantaniana é descrita, com dados sobre prevalência, intensidade media e amplitude das cargas parasitarias. H. cantaniana ocorreu com urna prevalência de 5.0 por cento nas 40 aves examinadas, com intensidade media de 17.5 e amplitude de 14-21 espécimes de cestóides. Não foram observadas lesões macroscópicas nos perus parasitados. As lesões provocadas por H. cantaniana eram representadas, principalmente, ou por múltiplos segmentos dos parásitos, acompanhados por discreta reação inflamatoria mista com a presera de células mononucleares e heterófilos, ou por severos processos inflamatorios transmurais, caracterizados pela presera de células mononucleares, ao longo das carnadas muscular e serosa das vilosidades e criptas intestinais. Estes representam os primeiros achados patológicos relacionados a presera de cestóides em perus a serem relatados no Brasil. Raillietina tetragona, não patogênica para as aves investigadas, ocorreu com baixa prevalência e amplitude de infecção de 2.5 por cento e 1-2 parásitos, respectivamente.

The pathology induced in turkeys (Meleagris gallopavo) by one cestode species Hymenolepis cantaniana is described together with data on prevalence, mean infection and range of worm burdens. H. cantaniana occurred with a prevalence of 5.0 percent in the 40 examined hosts in a range of 14-21 specimens and a mean intensity of 17.5. Gross lesions were not observed in the parasitized birds. Lesions due to H cantaniana mainly consisted of multiple segments of parasites, together with a mild mixed inflammatory reaction with the presence ofmononuclear cells and heterophils or severe transmural inflammatory processes, characterized by the presence ofmononuclear cells along the muscular and serosa layers of the intestinal villi and crypts. These are the first pathological findings related to the presence ofcestodes in turkeys to be reported in Brazil so far. Raillietina tetragona, not pathogenic to the present investigated turkeys, occurred with a low prevalence and range of infection of 2.5 percent and 1-2 worms, respectively.