Ctenocephalides orientis and Ctenocephalides felis in Thailand: Head geometry by species, sex and geography.

Fleas in the genus Ctenocephalides serve as biological vectors or intermediate hosts of microorganisms such as bacteria, rickettsia, protozoa and helminths. Ctenocephalides felis has a worldwide distribution, while C. orientis has long been considered as a subspecies of C. felis in Asia. To help the morphological recognition of these two species and further explore their differences, we used the geometric morphometric approach applied to the head. Both sexes were examined. Five anatomical landmarks of the head were used, and to capture the curvature of the front head, 10 semilandmarks were added. There was a consistent difference in species classification accuracy when considering landmarks only versus their combination with semilandmarks, suggesting the importance of the curve of the head as a taxonomic signal. Using or not the labels in the reclassification analyses, the head shape allowed by itself almost perfect recognition of the two species, in both sexes, even after adjustment for prior probabilities. The same approach disclosed a high level of sexual size and shape dimorphism in both species. The contribution of size variation to the discrimination by shape was much more important between sexes (from 27% to 45%) than between species (from 0.7% to 7.1%). Nevertheless, in our data, size never could represent a way to reliably recognise the sex of an individual, even less its species. Geographical variation in head shape could only be explored for the C. orientis sample. No significant correlation of morphometric variation with geography could be detected, which would be consistent with gene flow between Thai provinces. The geometric morphometric approach of the flea head, when it incorporates head curves, is a promising tool for rapid, economical, and accurate species and sex identification. It is, therefore, a useful tool for future epidemiological and demographic studies.

Morphological, biometrical, and molecular characterization of Ctenocephalides felis and Ctenocephalides canis isolated from dogs from different geographical regions.

In the present work, a comparative morphological, biometrical and molecular study of Ctenocephalides spp. isolated from dogs (Canis lupus familiaris) from different geographical regions (Spain, Iran, and South Africa) has been carried out. The internal transcribed spacer 1 (ITS1) sequences of Ctenocephalides felis and Ctenocephalides canis collected from dogs from different geographical regions have been determined to clarify the taxonomic status of these species and to assess intraspecific variation and interspecific sequence differences. In addition, a phylogenetic analysis based on ITS1 sequences has been performed. Four different morphological populations were observed in the individuals of C. felis collected from dogs from different geographical locations. Nevertheless, the comparative study of the ITS1 sequences of the different morphological populations observed in C. felis did not show molecular differences. The results showed clear molecular differences between C. felis and C. canis and some specific recognition sites for endonucleases were detected between both species. Thus, BfrBI and DraI sites have diagnostic value for specific determination in C. felis. The phylogenetic tree based on the ITS1 sequences of C. felis and C. canis revealed that all the populations of C. felis from different geographical regions clustered together and separated, with high bootstrap values, from C. canis. We conclude that ITS1 region is a useful tool to approach different taxonomic and phylogenetic questions in Ctenocephalides species.

Ctenocephalides felis felis vs. Ctenocephalides canis (Siphonaptera: Pulicidae): some issues in correctly identify these species.

Ctenocephalides felis felis is one of the most important ectoparasites of dogs and cats throughout the world, because of its geographical distribution, dual parasitological action as an infesting agent and a vector of diseases, the economic losses and the acquired resistance against common insecticides. In Brazil, it surpasses Ctenocephalides canis in distribution, number of host species infested, prevalence and epidemiological importance. However, in some studies the species have been misidentified on the basis of their morphological characters included in taxonomic keys. The morphological variations of chaetotaxy, especially those on the dorsal margin of the hind tibia and lateral metanotal area (LMA), found in certain specimens, have sometimes been erroneously treated as hybrids, in spite of the nonexistence of the two species of Ctenocephalides in the same municipality or region. This review focuses on the characteristics used for interspecific diagnosis and intraspecific variations found between the species. Data on distribution, hosts, prevalence and parasitological action are also presented as an auxiliary means for recognizing the species.