“Recently, head lice belonging to different mitochondrial clades were found to carry the DNA of several bacterial body louse-borne pathogens, such as B. quintana, B. recurrentis, Acinetobacter species and Y. pestis in natural settings [14,16,20,33±38]. Experimental studies have also demonstrated that head lice may also act as a vector of louse-borne diseases” PLoS Negl Trop Dis. 2018 Apr 17. See full article: "Body lice of homeless people reveal the presence of several emerging bacterial pathogens in northern Algeria." …
A Better Picture of Head-Lice Transmission, Aided by Math and a Fine-Toothed Comb
"As evidence mounts that head lice are developing resistance to widely used insecticides, the fight against lice is helped by a better understanding of how they spread—and how to stop them. Controlled studies of transmission of head lice (Pediculus humanus capitis) in real-world settings aren’t exactly feasible, though, because the most accurate investigation would require somehow tracking the detailed movements of, say, a classroom full of children as well as the individual lice those children might be carrying. So, researchers must find different ways to get at the same kind of information." See full article at Entomology Today. …
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Insights About Head Lice Transmission From Field Data and Mathematical Modeling
“Head lice infest millions of school-age children every year, both in developed and developing countries. However, little is known about the number of lice transferred among children during school activities, because direct methods to study this are almost impossible to implement. This issue has been addressed following an indirect method, which consist in collecting data of real infestation from several children groups and using a mathematical model of lice colonies to infer how the infestation observed might have evolved. By determining the events that would most likely lead to infestations as those observed, we find that severe infestations are most likely initiated by a relatively large number of lice transferred at the same moment or within relatively short time spans. In turn, …
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Response of Pediculus humanus capitis (Phthiraptera: Pediculidae) to Volatiles of Whole and Individual Components of the Human Scalp
“The head louse Pediculus humanus capitis (De Geer) (Phthiraptera: Pediculidae) is a cosmopolitan human ectoparasite causing pediculosis, one of the most common arthropod parasitic conditions of humans. The mechanisms and/or chemicals involved in host environment recognition by head lice are still unknown. In this study, we evaluated the response of head lice to volatiles that emanate from the human scalp. In addition, we identified the volatile components of the odor and evaluated the attractive or repellent activity of their pure main components. The volatiles were collected by means of Solid Phase microextraction and the extract obtained was chemically analyzed by gas chromatograph-mass spectrometer. Twenty-four volatile were identified in the human scalp odor, with the main …
Detection of bacterial pathogens including potential new species in human head lice from Mali
“In poor African countries, where no medical and biological facilities are available, the identification of potential emerging pathogens of concern at an early stage is challenging. Head lice, Pediculus humanus capitis, have a short life, feed only on human blood and do not transmit pathogens to their progeny. They are, therefore, a perfect tool for the xenodiagnosis of current or recent human infection. This study assessed the occurrence of bacterial pathogens from head lice collected in two rural villages from Mali, where a high frequency of head lice infestation had previously been reported, using molecular methods. Results show that all 600 head lice, collected from 117 individuals, belonged to clade E, specific to West Africa. Bartonella quintana, the causative agent of trench fever, …
Rickettsia Prowazekii (Epidemic Typhus)
“The human body louse is only a vector and not a reservoir because infected lice die five to seven days after they become infected with R. prowazekii. R. prowazekii multiplies in the gut epithelium of the louse which then detaches, ruptures, and releases rickettsiae into the feces. Rickettsiae from the infected feces enter the skin via abrasions or bite site and access the human host.”Sami M. Akram; Vidhya Prakash. See full article: "Rickettsia Prowazekii (Epidemic Typhus)." …
Pediculus capitis in schoolchildren of the urban area of Nuevo León, México: Analyses of associated factors
“Pediculosis capitis is a recurring problem affecting 6 to 12 millions of children annually; there are no epidemiological data on this subject in the state of Nuevo León, and there are few in México. Therefore, new contributions are needed to design control strategies based on factors that may predispose to head lice infestation… Our results showed that the P. capitis prevalence in Nuevo León is one of the highest in Mexico, that it constitutes a real public health problem, and that there is need to establish prevention programs at home and school to decrease or to control P. capitis with the support of public health authorities.”Biomedica. See the full article: "Pediculus capitis in schoolchildren of the urban area of Nuevo León, México: Analyses of associated factors." …
Identification of Novel Voltage-Gated Sodium Channel Mutations in Human Head and Body Lice (Phthiraptera: Pediculidae)
“In recent years, the increase of head louse infestation in Iran (7.4%) and especially in West-Azerbaijan Province (248%) has raised the hypothesis of insecticide resistance development. There are different mechanisms of resistance to various groups of insecticides, and knockdown resistance (kdr) is a prominent mechanism of resistance to pyrethroids, an insecticide group which is used conventionally for pediculosis control. For detection of kdr-type well-known amino acid substitutions (M815I-T917I-L920F) and additional sodium channel mutations potentially associated with kdr resistance in head and body lice, louse populations were collected from West-Azerbaijan and Zanjan Provinces of Iran.”Journal of Medical Entomology. See full article: "Identification of Novel Voltage-Gated Sodium …
Comparison of the proliferation and excretion of Bartonella quintana between body and head lice following oral challenge
“Human body and head lice are highly related haematophagous ectoparasites but only the body louse has been shown to transmit Bartonella quintana, the causative agent of trench fever. The mechanisms by which body lice became a vector for B. quintana, however, are poorly understood. Following oral challenge, green fluorescent protein-expressing B. quintana proliferated over 9 days postchallenge with the number of bacteria being significantly higher in whole body vs. head lice.”Insect Molecular Biology. See full article: "Comparison of the proliferation and excretion of Bartonella quintana between body and head lice following oral challenge." …