Body Lice Research Articles

Biophysical properties of human body louse nit related proteins: LNSP1, Agp9 and Agp22

The human parasitic head and body lice lay their eggs on either hair or clothing. Attachments of the eggs are possible because the female lice secret a glue substance from the accessory gland along with the egg, which hardens into a nit sheath that secures and protects the egg (The “nit” commonly refers to either the louse egg with an embryo or the empty hatched egg). Proteins called the louse nit sheath protein (LNSP) are suggested to be the major proteins of the nit sheath, but transcriptome profiling of the accessory glands indicated other proteins such as Agp9 and Agp22 are also expressed in the glands. In this study, human body louse LNSP1 (partial), Agp9, and Agp22 are recombinantly produced using the E. coli expression system, and the biophysical properties characterized. Circular dichroism analysis indicated that the secondary structure elements of LNSP1 N-terminal and middle-domains, Agp9, and Agp22 are prominently random coiled with up to 10–30% anti-parallel β-sheet element present. Size-exclusion chromatography profiles of LNSP1 proteins further suggested that the β-sheets made of the smaller N-terminal domain stacks onto the β-sheets of the larger middle-domain.

Molecular and Functional Characterization of GABA Receptor Subunits GRD and LCCH3 from Human Louse Pediculus Humanus Humanus.

Human louse Pediculus humanus is a cosmopolitan obligatory blood-feeding ectoparasite causing pediculosis and transmitting many bacterial pathogens. Control of infestation is difficult due to the developed resistance to insecticides that mainly target GABA (γ-aminobutyric acid) receptors. Previous work showed that Pediculus humanus humanus (Phh) GABA receptor subunit resistance to dieldrin (RDL) is the target of lotilaner, a synthetic molecule of the isoxazoline chemical class. To enhance our understanding of how insecticides act on GABA receptors, two other GABA receptor subunits were cloned and characterized: three variants of Phh-grd (glycine-like receptor of Drosophila) and one variant of Phh-lcch3 (ligand-gated chloride channel homolog 3). Relative mRNA expression levels of Phh-rdl, Phh-grd, and Phh-lcch3 revealed that they were expressed throughout the developmental stages (eggs, larvae, adults) and in the different parts of adult lice (head, thorax, and abdomen). When expressed individually in the Xenopus oocyte heterologous expression system, Phh-GRD1, Phh-GRD2, Phh-GRD3, and Phh-LCCH3 were unable to reconstitute functional channels, whereas the subunit combinations Phh-GRD1/Phh-LCCH3, Phh-GRD1/Phh-RDL, and Phh-LCCH3/Phh-RDL responded to GABA in a concentration-dependent manner. The three heteromeric receptors were similarly sensitive to the antagonistic effect of picrotoxin and fipronil, whereas Phh-GRD1/Phh-RDL and Phh-LCCH3/Phh-RDL were respectively about 2.5-fold and 5-fold more sensitive to ivermectin than Phh-GRD1/Phh-LCCH3. Moreover, the heteropentameric receptor constituted by Phh-GRD1/Phh-LCCH3 was found to be permeable and highly sensitive to the extracellular sodium concentration. These findings provided valuable additions to our knowledge of the complex nature of GABA receptors in human louse that could help in understanding the resistance pattern to commonly used pediculicides. SIGNIFICANCE STATEMENT: Human louse is an ectoparasite that causes pediculosis and transmits several bacterial pathogens. Emerging strains developed resistance to the commonly used insecticides, especially those targeting GABA receptors. To understand the molecular mechanisms underlying this resistance, two subunits of GABA receptors were cloned and described: Phh-grd and Phh-lcch3. The heteromeric receptor reconstituted with the two subunits was functional in Xenopus oocytes and sensitive to commercially available insecticides. Moreover, both subunits were transcribed throughout the parasite lifecycle.

Impact of a health educational interventional program on reducing the head lice infestation among pupils in an elementary school of a sub-tropical region: a quasi-experimental study

BackgroundPediculosis is an important social challenge that can be caused by human head louse, Pediculus humanus capitis. This infestation is cosmopolitan, especially in countries with low hygiene and sanitation. Regular health education classes for students and their parents are required to reduce this infestation in schools and families. This study aimed to evaluate the impact of a health education intervention program on reducing head lice among pupils of an elementary school.MethodsIn a quasi-experimental study, a total of 880 elementary school girls were screened for pediculosis in (2017–2018). The prevalence of pediculosis follow-up continued monthly until the end of the school year after a two months educational intervention course. Visual inspection was applied for initial diagnosis of infection. The suspected cases were confirmed by wood lamp and potassium hydroxide (KOH) microscopic examination. Also eight questions about diagnostic, epidemiology, treatment and prevention were answered in a questionnaire by 50 volunteer parents before and after the training intervention course, to evaluate their general knowledge and measure the effectiveness of learning. All data were statistically analyzed using SPSS software (version 20.0, SPSS, Inc., Chicago, IL, USA). McNemar’s test was also applied to investigate the prevalence rate before and after the intervention. A p -value of less than 0.05 was considered as statistically significant.ResultsAt the beginning of study, pre-intervention prevalence of pediculosis among pupils was 8.4% (49/594). The mean age in all pupils was 9.86 ± 1.83 years old and the most infestation was shown in fourth-grade students with 10 years old. Analysis of statistics demonstrated a significant difference between having infestation and the number of members in the families. Post-intervention phase led to a decreased prevalence of pediculosis in pupils to 3% (8/594) (p-value < 0.05). Based on statistical analysis of questions before and after the training in the questionnaire, a significant increase of parental knowledge was observed on the prevention program of pediculosis (p-value < 0.001).ConclusionThe prevalence of pediculosis was significantly reduced following the educational interventions in the school. The applied interventions may be implemented in other residual centers to get rid of this important infestation.

First report of classical knockdown resistance (kdr) mutation, L1014F, in human head louse Pediculus humanus capitis (Phthiraptera: Anoplura).

There are at least three known knockdown resistance (kdr) mutations reported globally in the human head louse Pediculus humanus capitis De Geer (Phthiraptera: Anoplura) that are associated with reduced sensitivity to pyrethroids. However, the prevalence of kdr mutation in head lice is not known in the Indian subcontinent. To identify kdr mutations in the Indian head lice population, the genomic region of the voltage-gated sodium channel gene encompassing IIS1-2 linker to IIS6 segments was PCR-amplified and sequenced from P. humanus capitis samples collected from different geographic localities of India. DNA sequencing revealed the presence of four kdr mutations: M827I, T929I, L932F and L1014F. The presence of a classical kdr mutation L1014F, the most widely reported mutation across insect-taxa associated with the kdr-trait, is being reported for the first time in P. humanus capitis.

Examination of vertical transmission of Bartonella quintana in body lice following multiple infectious blood meals.

Bartonella quintana is a re-emerging louse-borne pathogen. Horizontal transmission from the body louse vector (Pediculus humanus humanus) to a human host occurs through contact with infectious louse feces containing a high concentration of the bacteria. However, questions have remained about whether vertical transmission from infected vectors to their progeny, which could significantly influence the dynamics of transmission to humans, occurs in body lice. To address this subject, we performed a series of controlled laboratory experiments that examined the presence of B. quintana on the surface of and within eggs produced by female body lice that were provisioned multiple infectious blood meals to recapitulate the natural pathogen acquisition process. Our results demonstrate that B. quintana DNA can be detected from the surface of eggs by qPCR due to vertical transfer of infectious feces to the egg sheath during or after oviposition. However, viable B. quintana could not be cultured from the hemolymph of adult female lice or from within eggs that were surface sterilized, indicating a lack of true transovarial transmission. Based on this evidence, vertical transfer of B. quintana from infected adult lice to their eggs probably has a limited impact on the dynamics of transmission to humans.

Don't Be a Nit Wit; Know Your Lousy Companions!

Lice have been a burden on humans since antiquity. The species implicated in human infestations, the head louse (Pediculus humanus capitis), body louse (Pediculus humanus humanus), and pubic louse (Pthirus pubis), are very well adapted to the human host and are readily transmissible between and among individuals. In addition to dermal reactions and social stigmas associated with louse infestations, the body lice are of additional medical and public health concern in the spreading of bacterial agents associated with louse-borne relapsing fever, epidemic typhus, and trench fever. In the United States, pthiriasis, caused by P. pubis, is classified as a sexually transmitted infection. In this review, we provide an update on the taxonomy, epidemiology, biology, evolution, clinical importance, treatment and control, diagnosis, and reporting of parasitic human lice.

Vaktsyna Rudolfa Vaiglia u borotbi z vysypnym epidemichnym tyfom

Introduction. Vaccination has made a breakthrough in history by overcoming the infectious diseases that have plagued humanity for millennia. The twentieth century was marked by the invention of vaccines against epidemics typhus, which have become the only salvation in overcoming this disease. The history of the vaccine was developed on the example of the first effective vaccine against epidemic typhus, developed by a prominent Polish scientist, professor at the University of Lviv Rudolf Weigl, the history of vaccine development and the method of culturing R. Prowazekii in the intestine of Pediculus humanus corporis was studied. From Rickettsia Рrowazekii – the causative agent of epidemic typhus transmitted by aphids (Pediculus humanus corporis) in the history of mankind killed more people than in all known wars. Brazilian researcher Enrique da Rocha Lima differentiated described in detail and gave a specific name to the causative agent of typhus in 1916. In 1920, GW Epstein, as well as S. Burt Weilbach, John L. Todd and FW Palfrey in 1922 confirmed the etiological significance of R. Prowazekii in the presence of typhus. Biological and morphological characteristics, the life cycle of the pathogen and the impossibility of reproduction on artificial nutrient media were established. The aim of the study. According to the study of scientific sources to investigate the history of the technology of R. Weigl vaccine against epidemic typhus from its first series obtained in the laboratory and from 1930, when its production began, the period covering the 20-30s of the twentieth century. To establish that the scientific achievements of the scientists are not only the history of microbiology and virology, it is relevant today. Materials and methods. Content analysis, a method of systematic analysis of research on the typhus vaccine, was used. The implementation of scientific research began with a retrospective analysis of the scientific works of R. Weigl and his students. Selection of sources was carried out in the archives and scientific libraries of Lviv and the Research Institute of Epidemiology and Hygiene of Danylo Halytsky Lviv National Medical University, in scientometric databases PubMed, Medline, Web of Science, Google Scholar by keywords: lice, typhus, rubella, R. Prowazekii. 174 scientific works in English, Ukrainian, Polish, French and Russian were analyzed and sources were selected in which the issue of creating a vaccine against typhus, technology of its production, efficiency of application was covered. Results. The vaccine, developed by Professor Rudolf Weigl, author of the method of cultivating and accumulating the causative agent of this disease – R. Prowazekii in the intestine of the laboratory population of lice, despite the complexity of its preparation, for over 20 years was the only immunobiological drug to control typhus. Conclusions. We should be grateful to Rudolf Weigl and his students, who have often studied R. Рrowazekii at the cost of their lives and developed a vaccine against typhus, which has killed millions of people on our planet. Vaccination with a full dose of R. Weigl’s vaccine does not guarantee protection against infection, but reduces morbidity, completely eliminates mortality and facilitates the course of epidemic typhus.

Информационно–методическое письмо "Анализ заболеваемости педикулёзом в Российской Федерации и использование современных педикулицидных средств для его лечения и профилактики (по состоянию на 01.01 2022)"

The morbidity of human lice in the Russian Federation in 2016–2021 was analyzed. High intensive infection rates were registered in the Central, Northwestern and Far Eastern Federal Districts. The maximum level of pediculosis infestation of the population was noted in Moscow (88.7–96.1 % of all cases of this disease in the Central Federal District). The resistance of lice to permethrin led to a decrease in the pediculicidal activity of pediculicides based on it. The range of modern drugs effective against permethrin-resistant head and body lice and the dynamics of the ratio of pediculicides based on substances from different groups of insecticides during 1991–2021 were analyzed. Keywords: pediculosis, Pediculus humanus, resistance, pyrethroids, pediculicides.

Pyrethroid-linked resistance allelic mutations by molecular analysis in wild human head louse (Phthiraptera: Pediculidae) populations from schoolgirls of South Iran

BackgroundHuman head louse, Pediculus humanus capitis De Geer, 1767 (Anoplura: Pediculidae), is one of the most frequent ectoparasites infesting Homo sapiens worldwide. Reduced sensitivity to treatment due to genetic mutations, in particular knockdown resistance (kdr) (or target site insensitivity) allele, has led to this infestation prevalence. Molecular characterization of this resistance has a crucial impact on selecting appropriate treatment protocol. The aim of this study was to investigate kdr gene mutations on voltage-sensitive sodium channel (VSSC) among wild head lice samples from Fars province, southern Iran. MethodsHead lice were collected using plastic detection combs on girls enrolled in public schools from 10 counties in Fars province. The specimens were screened in 10 pools (each pool per county containing 35 specimens), with three pools (30%) being positive. Following species identification with valid entomological keys, 350 (68%) out of 514 randomly collected adult head lice were analyzed after their somatic genomic DNA extraction using Sinaclon kit. Samples were investigated by polymerase chain reactions (PCR), and the amplicon was subsequently sequenced. ResultsSequence analysis showed that the sodium channel genes in the pooled ectoparasites had two intron and three exon regions. Single (L840F), double (I836L, E837K), and triple novel point mutations (V875L, Q876P, S879V); the last involving two concomitant allelic substitutions; were discovered in the second and third exon regions of head louse DNA on chromosome II from three (30%) counties. Other exon or intron regions remained non-mutated from the remaining seven counties. ConclusionsThe detection of six amino acid substitutions from 30% of examined head lice among infested schoolgirls reveal that mutants are minutely developing. These findings provide further incentive to recapitulate the legitimacy of current control measures and resolve dynamics of resistance in human head louse populations.

Development of molecular detection methods of Bovicola ovis from sheep fleece

The sheep body louse (Bovicola ovis) commonly referred to as sheep lice are small chewing ectoparasites of sheep. Infection results in significant economic costs to the Australian sheep industry due to reduced wool quality caused by chronic itching from sheep rubbing and biting fleece. Treatment relies on use of insecticides; however, resistance has developed against pyrethroid and other insect growth regulator lousicides. There is urgent need to develop cost-effective lice management to reduce the use of insecticides, with the application of insecticidal treatments only applied when an infestation is detected. However, the current detection method relies on fleece parting for detection of B. ovis which is highly dependent on the skill of the inspector, the number of sheep examined, and the prevalence and severity of the infestation. To improve B. ovis detection, a highly sensitive (5 × 10−8 ng/μL) and specific multiplex quantitative PCR which simultaneously detects sheep lice and sheep DNA was developed. In addition, a B. ovis loop-mediated isothermal amplification (LAMP) assay was developed for field use. The B. ovis LAMP (Bov-LAMP) assay was optimized to reliably detect B. ovis from wool samples down to 5 × 10−6 ng/μL, with time to positive (Tp) < 10 min. Both assays demonstrate high sensitivity and specificity, enabling rapid identification of B. ovis DNA from sheep fleece samples and have the capacity to be used for ongoing management and surveillance of B. ovis in Australian sheep flocks.

Serologic testing for Bartonella in Manitoba, Canada, 2010-2020: a retrospective case series.

Background:Bartonella are gram-negative bacilli not identified by routine bacterial culture. The objectives of this study were to review the results of all serologic testing for Bartonella ordered in Manitoba, Canada, and to review cases with positive test results among adults to assess species identification, risk factors, clinical manifestations and outcomes.Methods:This retrospective study included all Bartonella serologic tests ordered in Manitoba and performed at the National Microbiology Laboratory, Winnipeg, from Jan. 1, 2010, until Dec. 31, 2020. We analyzed the aggregate data for all serologic tests for Bartonella for patients of all ages. We reviewed the charts of adult (age ≥ 18 yr) patients with serologic positivity for Bartonella who had a medical chart at 1 of Winnipeg’s 2 largest hospitals (Health Sciences Centre and St. Boniface Hospital) to extract clinical and demographic data and create a case series. Descriptive statistics were performed.Results:During the study period, 1014 Bartonella serologic tests were ordered in adult and pediatric patients, of which 24 (2.4%) gave a positive result. Sixteen adults (12 men and 4 women; mean age 48 yr) seen at a participating hospital had a positive result. Molecular species-level identification occurred on explanted cardiac valves in 5 (31%) of the 16 cases; B. quintana was identified in all 5. Six patients (38%) were diagnosed with probable B. quintana infection, for a total of 11 B. quintana cases (69%); 8 (73%) of the 11 had endocarditis. Four cases of B. quintana infection (36%) were associated with rural residence. Four cases (25%) of probable B. henselae were identified; 2 patients had fever and lymphadenopathy, and 2 had endocarditis. The remaining patient was deemed to have a false-positive result as his B. henselae titre was at the threshold for positivity, his B. quintana serologic test gave a negative result, and his clinical syndrome was not suggestive of Bartonella infection. Two patients died; both had multivalvular B. quintana endocarditis with ruptured intracranial mycotic aneurysms.Interpretation:Bartonella quintana was a common cause of Bartonella serologic positivity among adults in Manitoba in 2010–2020 and was associated with endocarditis and systemic embolization. As B. quintana is transmitted by body lice, active case finding for people who lack suitable housing, both in urban and rural settings, should prioritize those with elevated Bartonella titres to receive echocardiography and detect endocarditis before systemic embolization occurs.

Head lice dispose of blood meal fluid through breathing tubules

The moment when you realize that your itchy child has an infestation of headlice can be an instant of pure horror suffused with relief. Horror at the thought of the hideous creatures dining on your child's blood, and relief that they can usually be cleared. It's a rite of passage. Most insects that feast on fluids pee large volumes as they process their liquid lunches. But not lice. In fact, they don't urinate at all, for fear of alerting their host to their presence. Yet they lose fluid and dehydrate rapidly if separated from their succulent host, desiccating within 24 h when unable to feed regularly. So how do these pernicious pests dispose of the large volumes of fluid they ingest each day? Headlouse expert Ian Burgess (Insect Research &amp; Development Ltd, UK) decided to find out.Fortunately, Burgess had access to a ready supply of fresh head lice: the school children of Cambridgeshire, UK. ‘Some of our regulars just give us a call when the kids next get lice’, says Burgess, who has been working with local schools and parents for 25 years, helping them to vanquish tenacious infestations. Fortunately, the larger and more robust human clothing louse (Pediculus humanus humanus) survives more easily in the lab, so Burgess was able to keep a colony content by simply offering them a rabbit to feed on once a day.Monitoring the insects’ masses before and after dining, Burgess recorded that the smaller head lice (P. h. capitis ∼0.68 mg) consumed ∼0.11 mg of blood, losing 75% of the mass they gained within 3 h. In contrast, the larger clothing lice (∼1.87 mg) downed more than 50% of their body mass in blood (∼0.98 mg), losing the mass more slowly. ‘Most head lice returned to their pre-feeding mass by approximately 4 h after feeding, compared with 17–24 h for clothing lice’, says Burgess, explaining that head lice dine little and often.However, when Burgess checked how fast the insects lost mass after feeding in air at different humidities, there was no difference in the rate of mass loss, even at 100% humidity. ‘If humidity affected the rate of water loss, then the lice exposed to a saturated atmosphere would have some difficulty eliminating water… through cuticular evaporation’, says Burgess. In other words, the lice must be actively pumping water out of their bodies instead of simply allowing it to evaporate like sweat. But which orifices were the insects losing water from?As insects breathe through a network of tubules (tracheae) that open at structures – spiracles – at the surface of the body, Burgess recorded the mass change of clothing lice as they excreted water after dining and found that the creatures lost 15% of their blood meal mass over the next 40 min. Then, after feeding the lice, he smeared Vaseline (petroleum jelly) over their spiracles and the thoracic spiracles turned out to be particularly critical: blocking them reduced the insects’ water loss by ∼50%. In addition, when Burgess blocked the spiracles by immersing the insects in water – which should allow them to lose water but without breathing air – the lice also failed to lose mass; they could no longer inhale oxygen to power water excretion through their spiracles.Most intriguingly, when Burgess coated the insects’ abdomens in Vaseline, that supercharged their ability to lose water. The partially smothered insects disposed of more than 25% of their blood meal through the remaining spiracles. Burgess suspects that blocking the abdominal spiracles stimulates a feedback mechanism that triggers each louse to work harder to excrete water, ‘with the result that it “overdoes” it’, he says.

Evaluating the efficacy of Capparis spinosa Total flavonoids to control Bird Lice (Menacanthus stramineus)

The present study included an in-vitro and in-vivo insecticidal investigation for one of wild Iraqi plant Capparis spinosa total flavonids on locally chicken lice (Menacanthus stramineus). Extraction of total flavonoids from 115g of fresh plant samples by reflex extraction with 600ml distilled water with (10% v/ v) HCl, for 8 hours continuously and the aglycon part was obtained with ethyl acetate. The acetate layer was dried and the residue was weighted and subjected for qualitative and quantitative analysis. Three flavonoids concentrations of Capparis spinosa total Flavonoid (5,3 and 1) mg/ml in 100ml distilled water to treat a collected sample of Bird Lice (Menacanthus stramineus) in vitro and in vivo at different life stages in comparison to a traditional anti lice drug treatment permethrin (0.5mg/ml) as positive control. Distilled water application was considered as negative control. Results of present study showed that the plant was rich with different types of flavonoids and the effect of flavonoid extracts of the Capparis spinosa plant in the decimation of the different stage of chicken body lice, as the concentration factor had non-significant effect on the killing of adult and a significant effect on the killing of eggs/nymph, and this effect increased with the increase in the concentrations of the extract.

The Complete Mitochondrial Genome of the Chicken Body Louse, Menacanthus cornutus, and Evolutionary Patterns of Extensive Gene Rearrangements in the Mitochondrial Genomes of Amblycera (Psocodea: Phthiraptera).

Animal mitochondrial (mt) genomes are typically double-strand circular DNA molecules, but diverse structural variations have been widely found in multiple groups. In parasitic lice (Phthiraptera), the structure of mt genomes varies remarkably across all five suborders. In this study, we reported the complete mt genome of a chicken body louse, Menacanthus cornutus, which has a typical single circular mt chromosome and drastic mt gene rearrangements. This mt genome is 15,693 bp in length, consisting of 13 protein-coding genes, 23 tRNA genes, 2 rRNA genes, and a control region. A comparison with a typical insect mt genome suggested that two highly similar trnM are present in the mt genome of M. cornutus. Moreover, almost every single gene was rearranged, and over half of mt genes were inverted. Phylogenetic analyses inferred from the mt genome sequences supported the monophyly and position of Amblycera. Mapped over the phylogenetic relationships of Amblycera, we identified two inversion events for the conserved gene blocks in Boopidae and Menoponidae. The inverted ND4L-ND4 was likely a synapomorphic rearrangement in Menoponidae. Our study demonstrated the importance of sequencing mt genomes for additional taxa to uncover the mechanism underlying the structural evolution of the mt genome in parasitic lice.

Phylogenetic relationship between the endosymbiont \u201cCandidatus Riesia pediculicola\u201d and its human louse host

BackgroundThe 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.MethodsThe 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).ResultsThe 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.ConclusionOur 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

High Genetic Diversity and Rickettsia felis in Pediculus humanus Lice Infesting Mbuti (pygmy people), -Democratic Republic of Congo.

Pediculus humanus is an obligate bloodsucking parasite of humans that has two ecotypes, the head louse and the body louse, which share an intimate history of coevolution with their human host. In the present work, we obtained and analysed head and body lice collected from Mbuti pygmies living in the Orientale province of the Democratic Republic of the Congo. Cytochrome b DNA analysis was performed in order to type the six known lice clades (A, D, B, F, C and E). The results revealed the presence of two mitochondrial clades. Clade D was the most frequent (61.7% of 47), followed by clade A (38.3% of 47). Sixteen haplotypes were found in 47 samples, of which thirteen were novel haplotypes, indicating an unusually high genetic diversity that closely mirrors the diversity of their hosts. Moreover, we report for the first time the presence of the DNA of R. felis in three (6.4% of 47) head and body lice belonging to both clades A and D. Additional studies are needed to clarify whether the Pediculus lice can indeed transmit this emerging zoonotic bacterium to their human hosts.

Light sheet fluorescence microscopy for the investigation of blood-sucking arthropods dyed via artificial membrane feeding

Physical methods to control pest arthropods are increasing in importance, but detailed knowledge of the effects of some of these methods on the target organisms is lacking. The aim of this study was to use light sheet fluorescence microscopy (LSFM) in anatomical studies of blood-sucking arthropods in vivo to assess the suitability of this method to investigate the morphological structures of arthropods and changes in these structures over time, using the human louse Pediculus humanus (Phthiraptera: Pediculidae) as sample organism. Plasma treatment was used as an example of a procedure employed to control arthropods. The lice were prepared using an artificial membrane feeding method involving the ingestion of human blood alone and human blood with an added fluorescent dye in vitro. It was shown that such staining leads to a notable enhancement of the imaging contrast with respect to unstained whole lice and internal organs that can normally not be viewed by transmission microscopy but which become visible by this approach. Some lice were subjected to plasma treatment to inflict damage to the organisms, which were then compared to untreated lice. Using LSFM, a change in morphology due to plasma treatment was observed.These results demonstrate that fluorescence staining coupled with LSFM represents a powerful and straightforward method enabling the investigation of the morphology—including anatomy—of blood-sucking lice and other arthropods.Graphical

A Pain in the Flank

Abstract Culture-negative endocarditis is rarely encountered and that caused by Bartonella quintana has been very rarely described. Virtually, all such cases in the literature have been related to human body louse exposure due to homelessness or living in refugee camps or similar environments. We describe a case of B. guintana endocarditis in a healthy adult with no exposure to body lice and no other risk factors. The patient also presented without fevers, which is also very uncommon. Rather, she presented with isolated flank pain due to a renal infarction, which led to an investigation for an endovascular source for emboli. The diagnosis was confirmed by a combination of serology and polymerase chain reaction from the excised valve. This case highlights the potentially atypical nature of culture-negative endocarditis and the power of multiplex polymerase chain reaction to make diagnoses that likely would not have been established in the past.

Prevalence of Pediculus humunus capitis, Pediculus humanuscorporis, and Pthirus pubis in Al-Kut, Iraq.

Lice infestations or pediculosis occurs throughout the world and is caused by Pediculus humunus capitis (head louse), Pediculus humanuscorporis (body louse), and Pthirus pubis (crab louse). This study was conducted within March-October 2020 and aimed to investigate the presence of human lice among 1,632 individuals from 225 families living at different economic and social levels in AL-Kut city, Iraq, and its suburbs (urban, rural, and slum areas). Data collection was performed on volunteer families by completing survey forms and visual examinations. The families were divided by the number of members into 10-15, 7-9, 4-6, and 3-2 persons, for which, the infestation rates were estimated at 24.2%, 21.4%, 12.5%, and 8.6%, respectively. Moreover, in this study, urban, rural, and slum areas were infected at 11.5%, 33.6%, and 21.6 %, respectively. The infestation appeared in all ages, and the higher and lowest rates were obtained for the age ranges of 3-17 and 18-40 years old (79.04% and 20.9%), respectively. Based on the results, the rates of infestation were 21.8% and 13.3% in females and males, respectively. The findings of this study showed that the infection rate of Pediculus humanus corporis among the subjects aged 4-24 years old was 11.0% and that of Pthirus pubis was 3.0% in the cases aging 14-32 years old. Due to the high infestation with ectoparasites in these areas and large families, it is highly important to create conditions for health and provide information to control and prevent infection.

Prevalence of sheep lice and trends in control practices across Australia - Australian sheep parasite control surveys from 2003 to 2019.

The sheep body louse (Bovicola ovis) is a parasite of major economic concern in Australia. This article reports lice incidence and control practices on Australian sheep farms as determined by three cross-sectional surveys of the years 2003, 2011 and 2018. The incidence of live lice detected within a flock was similar across the survey years with a slight decline in 2018 (2003: 20%, 2011: 18.6% and 2018: 13.9%). In an average year, most farmers did not see any direct or indirect evidence of lice infestation (2011: 59.3% and 2018: 69.5%), however, over a five-year period 38.9% (2003), 66.3% (in 2011) and 55.8% (in 2018) reported seeing evidence of lice infestation at least once with significant variation between sheep producing regions in 2011. In an average year, nearly three quarters of respondents treated for lice (2011:73.5% and 2018: 73.3%) with the majority treating immediately following shearing and very few treating sheep with long wool. Even higher percentages treated for lice at least once in the preceding five-year period (2011: 86.2% and 2018: 87.5%). Backliner was the most popular method of chemical application for lice control in sheep off-shears or with short wool (2003: 77%, 2011: 73% and 2018: 74.3%). For long wool treatments, hand jetting declined in popularity from 2003 (64%) to 2011 (54%) and 2018 (8.6%) as backliners became more popular (2003: 36%, 2011: 51% and 2018: 60%). The use of benzoylphenyl urea insect growth regulators (IGR) for off-shears/short wool treatment declined from 2003 (92.8%) to 2011 (51%) and 2018 (2.9%) and were largely replaced by neonicotinoids and spinosad for backliner/spray-on products. The use of organophosphates declined for plunge dipping (2003: 83.8%, 2011: 83% and 2018: 7.7%). Spinosad use for plunge dipping off-shears/short wool increased over the survey years (2003, 0%, 2011: 9% and 2018:46.2%). The use of IGRs declined for backliner application on long wool and were mainly replaced by spinosad in 2011 and 2018. Fewer respondents reported suspected resistance to lice control products in 2018 (8%) compared with 2003 (26%) and 2011 (13%) with most reporting suspected resistance to IGR and synthetic pyrethroids and emerging suspicions of resistance to neonicotinoids in 2018. Resistance to lice control products also reduced in importance as a reason for recurring lice infestations between 2011 (ranked 2nd) and 2018 (ranked 6th). Biosecurity was important to sheep producers with the highest ranked reason for recurring lice infestations being from stray or purchased sheep.