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Seal lice, unique among insects, show remarkable adaptability to the extreme conditions of the deep sea. Evolving with their seal and sea lion hosts, they have managed to tolerate hypoxia, high salinity, low temperature, and elevated hydrostatic pressure. Given the diving capabilities of their mammalian hosts, which can reach depths of hundreds to thousands of meters, our study examines the morphological variation among closely related seal lice species infesting hosts with different maximum diving depths. In particular, our research reveals a significant morphological difference between lice associated with regular and deep-diving hosts, where lice from deep-diving hosts tend to be rounder. This could be an adaptation to withstand the high hydrostatic pressures found in the deep ocean. The rounded shape optimizes the louse's ability to withstand external pressure by redistributing it over a larger ventral/dorsal plane. This in turn minimizes the internal energy required to support body deformations, thereby increasing the louse's resilience in the deep sea environment.

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The ischnoceran louse, Lipeurus tropicalis, which normally infests Gallus gallus domesticus, was subjected to in vitro study (35 ± 1 C, 75-82% relative humidity, on a feather diet). The life table was computed, and its intrinsic rate of natural increase (r) was calculated using the data from in vitro experiments. The value of the intrinsic rate of natural growth (r) is 0.032. Given this rate, a population of L. tropicalis should double after 21.66 days, indicating that it is a moderately paced breeder.

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BACKGROUND: Bartonella quintana is a body louse-borne bacterium causing bacteremia and infective endocarditis. We aimed to describe B. quintana detection among arthropods and their hosts. METHODS: We searched databases in PubMed Central/MEDLINE, Scopus, Embase, and Web of Science from January 1, 1915 (the year of B. quintana discovery) to January 1, 2024, to identify publications containing specific search terms relating to B. quintana detection among arthropods. Descriptive statistics and meta-analysis of pooled prevalence using random-effects models were performed for all arthropods and body and head lice. RESULTS: Of 1265 records, 62 articles were included, describing 8839 body lice, 4962 head lice, and 1692 other arthropods, such as different species of fleas, bedbugs, mites, and ticks. Arthropods were collected from 37 countries, of which 28 had arthropods with B. quintana DNA. Among articles that reported B. quintana detection among individual arthropods, 1445 of 14,088 (0.1026, 95% CI [0.0976; 0.1077]) arthropods tested positive for B. quintana DNA, generating a random-effects model global prevalence of 0.0666 (95% CI [0.0426; 0.1026]). Fifty-six studies tested 8839 body lice, of which 1679 had B. quintana DNA (0.1899, 95% CI [0.1818; 0.1983]), generating a random-effects model pooled prevalence of 0.2312 (95% CI [0.1784; 0.2843]). Forty-two studies tested 4962 head lice, of which 390 head lice from 20 studies originating from 11 different countries had B. quintana DNA (0.0786, 95% CI [0.0713; 0.0864]). Eight studies detected B. quintana DNA exclusively on head lice. Five studies reported greater B. quintana detection on head lice than body lice; all originated from low-resource environments. CONCLUSIONS: Bartonella quintana is a vector-borne bacterium with a global distribution, disproportionately affecting marginalized populations. Bartonella quintana DNA has been detected in many different arthropod species, though not all of these arthropods meet criteria to be considered vectors for B. quintana transmission. Body lice have long been known to transmit B. quintana. A limited number of studies suggest that head lice may also act as possible vectors for B. quintana in specific low-resource contexts.

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BACKGROUND: Head lice infestation is a prevalent dermatological condition among adolescent girls, which has wide-ranging adverse physical, psychological, and emotional effects on their lives. However, these experiences have been sparsely documented. This study aimed to investigate the lived experiences of Iranian adolescent girls regarding head lice infestation. METHODS: In this phenomenological study, a purposive sampling technique was employed to select 15 adolescent girls who were experiencing head lice infestation. Collaboration was established with local schools to identify and recruit the participants. Subsequently, the purpose and nature of the study were explained to the identified participants and their guardians. Semi-structured in-depth interviews were conducted to gather the necessary data. The collected data underwent analysis using Colaizzi's seven-step method. To enhance the credibility of the findings, Lincoln and Guba's (2004) criteria were applied. The management of the data was facilitated through the utilization of MAXQDA software version 0.9.5. RESULTS: The average age of the participants, aged 12 to 17, was 14.5 (standard deviation = 1.7). In terms of education, the majority of them had completed upper secondary education (n = 8, 53.3%), followed by lower secondary education (n = 4, 26.6%). The participants' experiences were categorized into four main themes and 15 sub-themes. The main themes included living in the shadow of fear, torment of infestation, "struggling with head lice, and disturbing ramifications. The sub-themes encompassed social fear, fear of harm, fear of beauty decline, stigma, bullying behavior, self-blame, adversity, challenging struggle, effective coping, nonconforming behavior, family disruption, academic disruption, health threats, and confused mental state. CONCLUSION: During head lice infestation, adolescent girls endured negative experiences and extensive fears, considering it a significant ordeal. They encountered multiple challenges while dealing with lice and utilized both adaptive and maladaptive strategies to cope with the infestation. It is recommended to enhance public awareness regarding head lice infestation, and healthcare providers should offer emotional support and counseling services to affected girls and their families.

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INTRODUCTION: Head lice infestation remains a persistent public health concern among primary school children in resource-limited settings, affecting their well-being and academic performance. Despite previous studies, there is no consistent evidence on the prevalence and factors associated with head lice infestation. This study aimed to determine the prevalence and factors related to head lice infestation among primary school children in low and middle-income countries. METHODS: This review was conducted by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Relevant electronic databases, including PubMed, Cochrane Library, Web of Science, Science Direct, AJOL, and Google Scholar, were used to retrieve articles. The study included only published articles written in English languages between December 01, 2014 to January 31, 2024 for studies reporting the prevalence of head lice infestation or associated factors among primary school children in low- and middle-income countries. This review has been registered on PROSPERO with Prospero registration number CRD42024506959. The heterogeneity of the data was evaluated using the I2 statistic. A meta-analysis was conducted using STATA 17 software, with a 95% confidence interval. Publication bias was evaluated using funnel plots and statistical tests, such as Egger's and Beggs's tests, to identify publication biases in the included studies. Meta-regression was also carried out to assess the source of publication of publication bias. RESULTS: The review included 39 studies involving 105,383 primary school children. The pooled prevalence of head lice infestation among primary school children in low- and middle-income countries was 19.96% (95% CI; 13.97, 25.95). This review also found out that being a girl was 3.71 times (AOR = 3.71; 95% CI: 1.22-11.26) more likely to have head lice infestation as compared to boys, while children with a previous history of infestation were 4.51 times (AOR = 4.51; 95% CI: 2.31-8.83) more likely to have head lice infestation as compared to their counterparts. CONCLUSION: The overall prevalence of head lice infestation among primary school children in low- and middle-income countries was found to be high. Female gender, children who had a previous history of infestation, and family size were significant predictors of head lice infestation. As a result, policymakers and program administrators should focus on the identified determinants.

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Pediculus humanus capitis (head louse), which causes pediculosis capitis, remains a global health concern. Plant products are efficient alternative pediculicides for treating the human ectoparasite P. h. capitis which is resistant to permethrin. The study evaluates the toxicity and mechanisms of 6-gingerol and Cymbopogon citratus leaf extract on P. h. capitis. Pediculus humanus capitis adult stages were exposed to three different dosages of 6-gingerol and C. citratus crude leaf extract on filter sheets for 5, 10, and 30 min, respectively. The biochemical approach was used to assess the activity of detoxifying enzymes including acetylcholinesterase (AChE), glutathione S-transferase (GST), and oxidase. Scanning electron microscope (SEM) was used to investigate the ultrastructure of the morphological body of lice. After 30 min, 6-gingerol and C. citratus leaf extract killed P. h. capitis completely. Bioassay periods significantly affected lice mortality (P < 0.05). The LC50 values for 6-gingerol and C. citratus extract were 1.79 µg/cm2 and 25.0 µg/cm2, respectively. 6-Gingerol and C. citratus leaf extract significantly lower AChE and GST activity (P < 0.05). Cymbopogon citratus also caused morphological ultrastructure changes in P. h. capitis, including an irregularly formed head, thorax, abdominal respiratory spiracles, and belly. 6-Gingerol and C. citratus leaf extracts could be used as an alternate pediculicide to decrease P. h. capitis populations.

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This case report was prepared to provide information about Menacanthus pallidulus (Neumann, 1912), which was detected for the first time on a domestic chicken in Hatay province of Türkiye. Louse specimens collected from a chicken by a student were brought to Hatay Mustafa Kemal University Faculty of Veterinary Medicine, Department of Parasitology, and sent to Selçuk University Faculty of Veterinary Medicine, Department of Parasitology, for identification of species and microscopic examination revealed the presence of Menacanthus pallidulus (Neumann, 1912). Thus, with this study, the presence of M. pallidulus on domestic chickens was recorded for the first time in Türkiye.

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We analyzed body lice collected from persons experiencing homelessness in Winnipeg, Manitoba, Canada, during 2020-2021 to confirm vector species and ecotype and to identify louseborne pathogens. Of 556 lice analyzed from 7 persons, 17 louse pools (218 lice) from 1 person were positive for the louseborne bacterium Bartonella quintana.

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Seal lice (Echinophthirius horridus) are bloodsucking ectoparasites of phocid seals and vectors of pathogens like the heartworm, Acanthocheilonema spirocauda. Grey and harbour seal populations are recovering in German waters and wildlife health surveillance is crucial for wildlife conservation. A new, high effort sampling protocol for seal lice was applied for grey and harbour seals along the German North- and Baltic Sea coast. Freshly dead seals were systematically sampled within a health monitoring of stranded seals over 12 months. Prevalence, intensity and distribution patterns of seal lice were analysed. 58% of harbour seals (n = 71) and 70% of grey seals (n = 10) were infected with seal lice. A majority of harbour seals displayed mild levels of infection, while three were moderately and two were severely infected. The head was the preferred predilection site, indicating that E. horridus prefers body areas with frequent access to atmospheric oxygen. Nits and different developmental stages were recorded in all age classes in grey and harbour seals in all seasons. For the first time, copulating specimens of E. horridus were recorded on a dead harbour seal, highlighting that E. horridus reproduces throughout the year on seals of all age classes in German waters.

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This study aims to assess the effect of the COVID-19 pandemic on the consumption of self-care products for pediculosis capitis management, in Portugal. A segmented regression analysis of interrupted time series (March 2020) was performed from January 2017 to August 2023 to analyze the short- and long-term impact of the COVID-19 pandemic on the consumption of pediculicides and related products. Monthly rates of absolute consumption were estimated by community pharmacies' dispensing records. Portuguese municipalities were organized into quintiles according to their purchasing power index and percentage of youth, to study the association of these social and demographic variables on the sale of these products. COVID-19 pandemic significantly reduced the sales of products indicated for pediculosis. Since the start of the pandemic, an absolute decrease of 21.0 thousand packages was observed in the monthly average consumption (p < 0.0001) compared to the pre-pandemic period. After this reduction, the average monthly trend increased in the pandemic period in comparison with the previous period, although not significant (267.0 packages per month, p = 0.1102). Regions with higher disposable income and more young people were associated with higher sales of these products. The outbreak of the COVID-19 pandemic has had a notable impact on the sales of self-care products for pediculosis capitis in Portugal, in the short term. The lockdowns and other isolation measures implemented to control the spread of the virus may have led to a decrease in the number of head lice cases, consequently resulting in a reduction in sales of products.

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BACKGROUND OBJECTIVES: Lice infestation is considered as a reemerging problem as well as a health challenge. Based on Protection Motivation Theory, the present study was conducted to investigate the effectiveness of training mothers in regard to pediculosis preventive behavior among school students. METHODS: In a critical trial, 180 mothers of primary school daughters were assessed in two study groups in the Iranian city of Qom in 2021. They received training intervention in a course of four ninety-minute sessions during four weeks. After six months, the post-test questionnaire and the checklist were completed by them. The data were gathered using a valid and reliable questionnaire. Finally, data analysis was performed using SPSS 20. RESULTS: After the training intervention, a significant difference was observed within the intervention group in scores of the prevention motivation constructs (P<0.001). Besides, there was a significant difference between the mean scores of the preventive behavior of the mothers and daughters in the intervention group before the training intervention and six months after it (P<0.001). However, no significant difference was seen before and after the intervention in the control group (P>0.05). Additionally, no significant differences were observed between the intervention and control groups (P<0.001) in terms of comparing the mean score differences of all the constructs of protection motivation theory, the mothers' behavior and the daughters' behavior checklist. INTERPRETATION CONCLUSION: The results indicate the effectiveness of training mothers based on Protection Motivation Theory in regard to pediculosis. Therefore, it seems that in developing training programs, utilizing this theory could prove useful to bring about changes in the individuals' behavior regarding the prevention of pediculosis.

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Four genera and at least fifty species of chewing lice have been recorded infesting hummingbirds (Trochilidae). Here, we record for the first time, the genus Trochiliphagus in Brazil, as well as, a new host record for Trochiliphagus mellivorus Carriker, the fork-tailed woodnymph, Thalurania furcata.

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Koi carp are globally known for their colors and cultural significance. The introduction of these fish to new environments poses a threat to local biodiversity, in addition to releasing parasites, such as argulid ectoparasites. This study presents a record of Argulus japonicus infecting carp in an artificial lake in Southern Brazil using morphological and molecular methods, with a 100% prevalence (n = 3) and a mean intensity of 21.6 parasites per host, distributed over the body surface. The invasion history of hosts in the study locality indicates that the introduction of A. japonicus occurred decades before its first formal record in Brazil.

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BACKGROUND: The chicken body louse is an obligate ectoparasite of domestic chickens. Chicken body lice feed on feathers, and infestation with this louse is linked to decreases in egg production, hen weight, and feed conversion efficiency. However, it is unknown how chicken body lice impact egg-laying chickens in cage-free environments. Welfare and behavior metrics were collected from flocks of egg-laying chickens either infested with chicken body lice or left uninfested. METHODS: In two trials, two flocks of cage-free commercial egg-laying chickens were infested with chicken body lice or maintained as uninfested controls. At three timepoints, behavior and welfare of all chickens was measured. On-animal sensors were used to quantify pecking, preening, and dustbathing behavior. Other animal-based welfare metrics included recording comb wounds and skin lesions. RESULTS: Birds infested with chicken body lice exhibited significantly more preening behaviors than uninfested birds, even at low louse levels. Moderate or severe skin lesions were detected on birds that were moderately infested with chicken body lice while skin lesions were never detected on uninfested birds. CONCLUSIONS: The welfare of chickens was impacted by the chicken body louse, a chewing louse that primarily feather feeds. Evidence of skin lesions on infested birds suggests that lice may cause more damage to birds than previously thought, and further evaluation of louse economic damage is necessary.

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There is a large burden of treatable dermatologic conditions in refugee populations. Parasitic infestations are particularly common when there are barriers to basic hygiene, crowded living or travel conditions, and lack of access to health care. Body lice are associated with anemia and can transmit a variety of diseases; chronic impetigo secondary to scabies is a leading cause of chronic kidney disease globally. Dermatologists have unique skills to identify skin infections, inflammatory diseases, and infestations. Appropriate dermatologic care has the potential to improve overall outcomes.

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Pthiriasis palpebrarum, a rare condition caused by Phthirus pubis, can mimic blepharitis and manifest as intense itching, inflammation and eyelid redness. We describe a case of Pthiriasis palpebrarum in a young girl with right upper eyelid discomfort. A slit lamp examination revealed eggs on her eyelashes and adult lice on the eyelids' surface. Dermatology consultation confirmed the diagnosis and successful treatment followed. Family evaluation uncovered genital Phthiriasis pubis in her parents, who received appropriate treatment. This report emphasises the importance of accurate diagnosis and management of this masquerading condition by careful slit lamp and microscopic evaluation. It also highlights the significance of comprehensive family history and examination.

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