Highly Resolved Genomes of Two Closely Related Lineages of the Rodent Louse Polyplax serrata with Different Host Specificities.

Sucking lice of the parvorder Anoplura are permanent ectoparasites with specific lifestyle and highly derived features. Currently, genomic data are only available for a single species, the human louse Pediculus humanus. Here, we present genomes of two distinct lineages, with different host spectra, of a rodent louse Polyplax serrata. Genomes of these ecologically different lineages are closely similar in gene content and display a conserved order of genes, with the exception of a single translocation. Compared with P. humanus, the P. serrata genomes are noticeably larger (139 vs. 111 Mbp) and encode a higher number of genes. Similar to P. humanus, they are reduced in sensory-related categories such as vision and olfaction. Utilizing genome-wide data, we perform phylogenetic reconstruction and evolutionary dating of the P. serrata lineages. Obtained estimates reveal their relatively deep divergence (∼6.5 Mya), comparable with the split between the human and chimpanzee lice P. humanus and Pediculus schaeffi. This supports the view that the P. serrata lineages are likely to represent two cryptic species with different host spectra. Historical demographies show glaciation-related population size (Ne) reduction, but recent restoration of Ne was seen only in the less host-specific lineage. Together with the louse genomes, we analyze genomes of their bacterial symbiont Legionella polyplacis and evaluate their potential complementarity in synthesis of amino acids and B vitamins. We show that both systems, Polyplax/Legionella and Pediculus/Riesia, display almost identical patterns, with symbionts involved in synthesis of B vitamins but not amino acids.

Acute prurigo simplex in humans caused by pigeon lice

Abstract: Pigeon lice are insects that feed on feathers of these birds; their life cycle includes egg, nymph and adult and they may cause dermatoses in humans. Four persons of the same family, living in an urban area, presented with widespread intensely pruritic erythematous papules. A great number of lice were seen in their house, which moved from a nest of pigeons located on the condenser of the air-conditioning to the dormitory of one of the patients. Even in urban environments, dermatitis caused by parasites of birds is a possibility in cases of acute prurigo simplex. Pigeon lice are possible etiological agents of this kind of skin eruption, although they are often neglected, even by dermatologists.

Ecological Niches of Sucking Lice (Phthiraptera: Anoplura) and Their Coevolution Relationship with Small Mammal Hosts in Yunnan, China / 中国寄生虫学与寄生虫病杂志

Objective To investigate the ecological niches of sucking lice (Phthiraptera: Anoplura) on the body surface of small mammal hosts and the co-evolutionary relationship between lice and mammal hosts in Yunnan Province. Method Thirty species of small mammals were captured and used as 30 resource sequences. The distribution and composition of the dominant 22 species of sucking lice on the body surface of the 30 species small mammal hosts were analyzed as the utilization proportion for each resource sequence. The niche breadth and proportional similarity were measured. SPSS 13.0 statistical software was used for analyzing the niche overlap matrix of sucking lice by hierarchical clustering analysis, and a dendrogram was made. Results The niche breadth was narrow for most species of sucking louse. Among the detected species, Hoplopleura pacifica showed the widest niche breadth, but only 0.1536. Indices of niche proportional similarity of most sucking lice were relatively small from 0.0005 to 0.4695. The 22 species of sucking lice were classified into 16 niche overlap groups, by ?=5.5, through a hierarchical clustering analysis for the niche overlaps, and the clustering process of most sucking lice was late. Conclusion The sucking lice have a high specificity for hosts, of which different species show an apparent niche divergence on host selection. The results reveal a high coevolution between sucking lice and the mammal hosts.