Parasites & Vectors

Abstract Background Globally, the disease ecology of reptiles remains understudied, even for threatened and iconic species such as the Galápagos marine iguana ( Amblyrhynchus cristatus ). Although marine iguanas are parasitized by distinct species of ticks and mites, research on vector-borne diseases for this species is limited. Methods In this study, we detected 16S ribosomal RNA (rRNA) sequences of Candidatus Allocryptoplasma in transcriptomic data from marine iguana blood samples. These 16S rRNA sequences were further characterized through phylogenetic analysis and a haplotype network. Results Our analysis revealed the first molecular evidence for the infection of marine iguanas with Candidatus Allocryptoplasma, a candidate genus in the family Anaplasmataceae with unknown pathogenic potential, likely transmitted by ticks. Phylogenetic analysis of the novel 16S rRNA sequences together with available Anaplasmataceae sequences confirmed their assignment to this candidate genus. A haplotype network analysis indicated that the agent infecting the marine iguana represents a distinct lineage within the known Ca . Allocryptoplasma diversity. Conclusions Candidatus Allocryptoplasma had a high prevalence within marine iguanas, infecting individuals across most of the geographical range of this species. To elucidate the transmission dynamics of this bacterium in the Galápagos ecosystem, ectoparasites of the marine iguana and shared vertebrate hosts should be screened for infection with Ca . Allocryptoplasma. Graphical Abstract

Abstract Background Hemotropic Mycoplasma spp. (hemoplasmas) parasitize erythrocytes and cause hemolytic anemia in several mammalian species, including cats. Mycoplasma haemofelis ( Mhf ), “ Candidatus Mycoplasma haemominutum” ( C Mhm) and “ Candidatus Mycoplasma turicensis” ( C Mt) are the three main feline hemoplasma species. A species closely related to C Mhm was recently proposed as a putative novel species based on the 23S ribosomal RNA (rRNA) gene. Methods In this study, 16S and 23S rRNA genes were used to investigate hemoplasma diversity in cats. Blood samples from 388 cats were obtained and screened for hemoplasma infection based on a PCR assay targeting the 16S rRNA gene. Positive samples were sequenced based on the 16S and 23S rRNA genes. All obtained sequences were analyzed by the nucleotide Basic Local Alignment Search Tool (BLASTn), the DnaSP6 computer program, phylogenetic construction, genetic network and pairwise identity matrix. Results The 388 blood samples collected from the cats were screened for hemoplasma infection. The tests showed that 68 cats (17.5%, 95% confidence interval [CI] 13.9–21.7%) were positive for hemoplasmas. Of these 68 positive samples, 49 were successfully sequenced for both the 16S and 23S rRNA genes and the sequences subsequently assigned to 11 nucleotide sequence types (ntSTs). The 16S rDNA analysis revealed one Mhf group, at least three groups within C Mhm and at least two groups within C Mt. Notably, we identified C Mhm as well as two putative species closely related to C Mhm from 23S rDNA analysis, including one that has been previously identified. In contrast, the identity of the C Mt-derived 23S rDNA sequence ntST#11 remains unclear due to the lack of C Mt reference sequences, highlighting the need for more comprehensive C Mt data in public databases. Conclusions Our data suggested the presence of two putative species related to C Mhm identified in domestic cats in Thailand. Integrating analyses of independent genetic markers, such as 16S and 23S rRNA genes, would enhance hemoplasma species identification and novel species discovery. Graphical abstract

Abstract Background The human louse (Pediculus humanus) is a haematophagous ectoparasite that is intimately related to its host. It has been of great public health concern throughout human history. This louse has been classified into six divergent mitochondrial clades (A, D, B, F, C and E). As with all haematophagous lice, P. humanus directly depends on the presence of a bacterial symbiont, known as “Candidatus Riesia pediculicola”, to complement their unbalanced diet. In this study, we evaluated the codivergence of human lice around the world and their endosymbiotic bacteria. Using molecular approaches, we targeted lice mitochondrial genes from the six diverged clades and Candidatus Riesia pediculicola housekeeping genes. Methods The mitochondrial cytochrome b gene (cytb) of lice was selected for molecular analysis, with the aim to identify louse clade. In parallel, we developed four PCR primer pairs targeting three housekeeping genes of Candidatus Riesia pediculicola: ftsZ, groEL and two regions of the rpoB gene (rpoB-1 and rpoB-2). Results The endosymbiont phylogeny perfectly mirrored the host insect phylogeny using the ftsZ and rpoB-2 genes, in addition to showing a significant co-phylogenetic congruence, suggesting a strict vertical transmission and a host–symbiont co-speciation following the evolutionary course of the human louse. Conclusion Our results unequivocally indicate that louse endosymbionts have experienced a similar co-evolutionary history and that the human louse clade can be determined by their endosymbiotic bacteria. Graphical Abstract

Abstract Background Rickettsia spp. are human pathogens that cause a number of diseases and are transmitted by arthropods, such as ixodid ticks. Estonia is one of few regions where the distribution area of two medically important tick species, Ixodes persulcatus and I. ricinus, overlaps. The nidicolous rodent-associated Ixodestrianguliceps has also recently been shown to be present in Estonia. Although no data are available on human disease(s) caused by tick-borne Rickettsia spp. in Estonia, the presence of three Rickettsia species in non-nidicolous ticks has been previously reported. The aim of this study was to detect, identify and partially characterize Rickettsia species in nidicolous and non-nidicolous ticks attached to rodents in Estonia. Results Larvae and nymphs of I.ricinus (n = 1004), I. persulcatus (n = 75) and I.trianguliceps (n = 117), all removed from rodents and shrews caught in different parts of Estonia, were studied for the presence of Rickettsia spp. by nested PCR. Ticks were collected from 314 small animals of five species [Myodes glareolus (bank voles), Apodemus flavicollis (yellow necked mice), A.agrarius (striped field mice), Microtus subterranius (pine voles) and Sorex araneus (common shrews)]. Rickettsial DNA was detected in 8.7% (103/1186) of the studied ticks. In addition to identifying R.helvetica, which had been previously found in questing ticks, we report here the first time that the recently described I.trianguliceps-associated Candidatus Rickettsia uralica has been identified west of the Ural Mountains. Graphical Abstract

AbstractThe fast development of molecular taxonomy is impacting our knowledge of the world parasite diversity at an unprecedented level. A number of operational taxonomic units have been uncovered and new species described. However, it is not always that new parasite species are being described in compliance with the International Code of Zoological Nomenclature. This is the case of “Candidatus Dirofilaria hongkongensis”, a nematode found in dogs, jackals and humans in Hong Kong and parts of India. This name has been proposed without a formal description and without the designation of a holotype, and therefore is an unavailable name. Finally, we argue that using the provisional status Candidatus in zoological nomenclature is inappropriate, considering this term is not considered in the International Code of Zoological Nomenclature.