Pediculosis humanus capitis in 6-7 years old schoolchildren in Valencia, Spain.

OBJECTIVES: Pediculosis humanus capitis is a worldwide public health concern that affects mostly school-aged children. The aim of this study is to determine the rate of pediculosis and to determine possible risk factors in a group of primary school children in Valencia, Spain; 227 children, 6-7 years old, were selected from 7 schools. METHODS: A self-reported questionnaire completed by the parents/guardians about the presence of pediculosis in their children and their knowledge about pediculosis. The results recorded in the questionnaire were analysed by SPSS® software. RESULTS: 30.4% of the children had pediculosis. The results showed significant variation (p < 0.05) in prevalence depending on the following factors: sex, hair length, level of parental education, family size, presence of affected family member in the home, and frequency of hair washing. Less than half of parents/guardians showed an appropriate level of knowledge on pediculosis. Pediculosis remains a health problem in Valencian schoolchildren. The family size and existence of another member with pediculosis were shown to be the main potentiating factors. CONCLUSIONS: Parents are not sufficiently informed about pediculosis and adopt inappropriate practices. There is a need to promote studies with the objective of determining risk factors for pediculosis as well as the need for actions to increase the knowledge of parents and healthcare professionals on this parasitosis to prevent outbreaks in the community, assure correct treatment and maintain effective epidemiological surveillance.

Embryonic Development of Pediculus humanus capitis: Morphological Update and Proposal of New External Markers for the Differentiation Between Early, Medium, and Late Eggs.

BACKGROUND AND OBJECTIVES: The head louse Pediculus humanus capitis is a cosmopolitan ectoparasite that causes pediculosis. In the study of human lice, little research focuses on embryonic development. Currently, external markers of embryonic development represent a new approach in the evaluation of ovicidal drugs. The objective of this work was to update the morphology of embryonic development and propose novel external markers to differentiate between early, medium, or late P. h. capitis eggs. METHODS: Using stereoscopic light microscopy, we describe the morphological characteristics of P. h. capitis eggs with a special focus on embryonic development. RESULTS: The morphological analysis of the eggs revealed the presence of an operculum with ten aeropyles, although no micropyles were observed. For the first time, the presence of defective eggs that were non-viable due to the apparent absence of yolk granules was documented. The early eggs presented yolk granules and developing germ bands, while the medium eggs presented an embryonic rudiment and the outlines of the eyes and limbs. In late eggs, the head with eyes and antennae, the thorax with three pairs of legs, and the abdomen with six pairs of spiracles were observed as formed structures. At the end of this stage, the embryos acquired the morphology of the nymph I stage. CONCLUSION: We propose novel biomarkers (e.g., the presence of spiracles and antennae, the proportion of the egg occupied by the embryo) to facilitate the differentiation between the developmental stages. The updated morphological characteristics of P. h. capitis eggs facilitate the standardization of toxicological tests in the quest for ovicidal drugs.

Pediculus humanus capitis: a study of the male genitalia using a combined stereoscopic, confocal laser scanning, and scanning electron microscopy approach.

BACKGROUND: The male genital structures of arthropods are key features in the taxonomic and phylogenetic study of these organisms. The male genitalia of the head louse Pediculus humanus capitis are complex organs which are partly composed of structures that dynamically extrude during copulation. METHODS: Here, we describe the morphology of the genitalia of P. humanus capitis at the copulation stage, and at rest, by using stereoscopic microscopy, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM). RESULTS: CLSM and SEM images revealed that the vesica is composed of two distinct anatomical parts, the proximal lobe and the distal lobe. Both lobes have short and narrow spines, as well as long and wide scales with either sharp or rounded tips. The rounded scales vary in size and have a wavy base and rounded tips, and thus resemble a tongue in appearance. We identified a gland-like area on the penis with 11 shallow circular depressions, and a flat area with 14-16 exit orifices. The apical end of the penis has a foliaceous trifurcation and serves to expel the contents of the ejaculatory duct. These characteristics were recorded for all the specimens analyzed, indicating that these structures are highly conserved; to our knowledge, they have not been previously reported for any suborder of lice. CONCLUSIONS: To the best of our knowledge, our results reveal for the first time the morphological details, and complexity, of the male genitalia of the head louse P. humanus capitis at different stages of copulation. The new approach described here provided information that should be taken into consideration in future research on the genitalia of lice. Application of this approach will also impact the taxonomic and phylogenetic study of other insect taxa.

Trichuris vulpis (Froelich, 1789) infection in a child: a case report.

We present a human infection with the canine whipworm, Trichuris vulpis, in a child suffering from rhinitis with a diagnosis of rhinitis. T. vulpis eggs resemble those of T. trichiura but they can be differentiated based on their morphological features and egg size, using micrometry with an ocular micrometer. T. vulpis eggs measured an average of 90 µm by 44 µm (range 86-99 µm by 38-47 µm). Prevalence of hookworms (28.1%), Toxocara canis (11.8%), and Trichuris vulpis (3.5%) was found in 292 fecal samples of dogs collected at the peri-domicile, which showed that the risk of infection was not only fortuitous. The treatment of canine whipworm infections is similar to that of T. trichiura infection. We recommend differentiation of the 2 species for their epidemiological and prevention implications.