[A biography of infectious diseases: Hans Zinsser and his Rats, Lice and History].

Hans Zinsser, a well-known bacteriologist and immunologist in the United States in the early 20th century, made great advancement in the research of pathogen of typhus and its vaccine, with the epidemic typhus renamed after him. His masterpiece, Rats, Lice and History, teased out the co-evolutionary process of infectious diseases and their related organisms, focusing on specific cases and the development history of typhus. In this sense, he revealed the tremendous impact of infectious diseases on human history. He examined microorganisms and humans equally rather than simply from a human point of view. He analysed the pathological features of infectious diseases and provided professional insights into historical events of infectious diseases, such as the origin of syphilis and the plague of Athens, based on sufficient citations and references. He also advocated interpreting the history of infectious diseases with a holistic insight of history. His book, Rats, Lice and History, has been reprinted many times after its first publication, driving the following scholars to put the history of infectious diseases into a grand background of human development, enhancing the comprehension of ecology and politics and promoting the development of research in the history of diseases including life sciences, history and other disciplines.

Daily patterns in parasite processes: diel variation in fish louse transcriptomes.

Parasites, similar to all other organisms, time themselves to environmental cues using a molecular clock to generate and maintain rhythms. Chronotherapeutic (timed treatment) techniques based on such rhythms offer great potential for improving control of chronic, problematic parasites. Fish lice are a key disease threat in aquaculture, with current control insufficient. Assessing the rhythmicity of fish lice transcriptomes offers not only insight into the viability of chronotherapy, but the opportunity to identify new drug targets. Here, for the first known time in any crustacean parasite, diel changes in gene transcription are examined, revealing that approximately half of the Argulus foliaceus annotated transcriptome displays significant daily rhythmicity. We identified rhythmically transcribed putative clock genes including core clock/cycle and period/timeless pairs, alongside rhythms in feeding-associated genes and processes involving immune response, as well as fish louse drug targets. A substantial number of gene pathways showed peak transcription in hours immediately preceding onset of light, potentially in anticipation of peak host anti-parasite responses or in preparation for increased feeding activity. Genes related to immune haemocyte activity and chitin development were more highly transcribed 4 h post light onset, although inflammatory gene transcription was highest during dark periods. Our study provides an important resource for application of chronotherapy in fish lice; timed application could increase efficacy and/or reduce dose requirement, improving the current landscape of drug resistance and fish health while reducing the economic cost of infection.

The impact of anti-sea lice pesticides, azamethiphos and deltamethrin, on European lobster (Homarus gammarus) larvae in the Norwegian marine environment.

Anti-sea lice pesticides, used in the salmonid aquaculture industry, are a growing environmental concern due to their potential to adversely affect non-target crustaceans. Azamethiphos and deltamethrin are two bath treatment pesticides used on salmon farms in Norway, however, limited information is available on their impact on European lobster (Homarus gammarus) larvae in the Norwegian marine environment. Here, we firstly report the lethal (LC50) and effective (EC50) concentrations of azamethiphos and deltamethrin for stage I and stage II larvae, following 1-h exposures. Using a hydrodynamic model, we also modelled the dispersal of both compounds into the marine environment around selected Norwegian farms and mapped the potential impact zones (areas that experience LC50 and EC50 concentrations) around each farm. Our data shows that azamethiphos and deltamethrin are acutely toxic to both larval stages, with LC50 and EC50 values below the recommended treatment concentrations. We also show that the azamethiphos impact zones around farms were relatively small (mean area of 0.04-0.2 km2), however deltamethrin impact zones covered much larger areas (mean area of 21.1-39.0 km2). These findings suggest that deltamethrin poses a significant risk to European lobster in the Norwegian marine environment while the impact of azamethiphos may be less severe.

Efficacy of bornyl acetate and camphene from Valeriana officinalis essential oil against two storage insects.

The essential oil was extracted from the roots of Valeriana officinalis L. by hydrodistillation. The qualitative and quantitative analysis of its chemical constituents was conducted on GC-MS and GC-FID in this study. Seventeen compounds were detected and the major constituents included bornyl acetate (48.2%) and camphene (13.8%). The toxic and repellent effects of the essential oil and its two major constituents were evaluated on Liposcelis bostrychophila and Tribolium castaneum. The results of bioassays indicated that the essential oil showed the promising fumigant and contact toxicity against L. bostrychophila (LC50 = 2.8 mg/L air and LD50 = 50.9 µg/cm2, respectively) and the notable contact effect on T. castaneum (LD50 = 10.0 µg/adult). Meanwhile, the essential oil showed comparable repellent effect on T. castaneum at all testing concentrations. Bornyl acetate and camphene also exhibited strong fumigant and contact toxicity against both species of pests (LC50 = 1.1, 10.1 mg/L air and LD50 = 32.9, 701.3 µg/cm2 for L. bostrychophila; > 126.3, 4.1 mg/L air, and 66.0, 21.6 µg/adult for T. castaneum). Bornyl acetate and camphene showed moderate repellent effect on T. castaneum and conversely showed attractant effect on L. bostrychophila. This work highlights the insecticidal potential of V. officinalis, which has been noted as a traditional medicinal plant.

Fumigant and repellent activities of essential oil extracted from Artemisia dubia and its main compounds against two stored product pests.

The major chemical constituents of the essential oil extracted from Artemisia dubia wall. ex Bess. (Family: Asteraceae) were found as terpinolene (19.02%), limonene (17.40%), 2,5-etheno[4.2.2]propella-3,7,9-triene (11.29%), isoelemicin (11.05%) and p-cymene-8-ol (5.93%). Terpinolene and limonene were separated as main components from the essential oil. The essential oil showed fumigant toxicity against Tribolium castaneum and Liposcelis bostrychophila with LC50 values of 49.54 and 0.74 mg/L, respectively. The essential oil and isolated compounds of A. dubia showed repellency activities against both insects. Terpinolene and limonene showed the fumigant toxicity against T. castaneum. Terpinolene showed obvious fumigant toxicity against L. bostrychophila. The results indicated that the essential oil of A. dubia had potential to be developed into natural insecticides for controlling stored product pests.

Electron Microscopic Alterations in Pediculus humanus capitis Exposed to Some Pediculicidal Plant Extracts

Head lice, Pediculus humanus capitis, infestation is an important public health problem in Egypt. Inadequate application of topical pediculicides and the increasing resistance to the commonly used pediculicides made the urgent need for the development of new agents able to induce irreversible changes in the exposed lice leading to their mortality. The aim of the present work is to evaluate pediculicidal efficacy of some natural products such as olive oil, tea tree oil, lemon juice, and ivermectin separately in comparison with tetramethrin-piperonyl butoxide (licid), as a standard pediculicide commonly used in Egypt. The effects of these products were evaluated by direct observation using dissecting and scanning electron microscopes (SEM). Results showed that after 1 hr exposure time in vitro, absolute (100%) mortalities were recorded after exposure to 1% ivermectin and fresh concentrate lemon juice. The mortalities were decreased to 96.7% after exposure to tea tree oil. Very low percentage of mortality (23.3%) was recorded after 1 hr of exposure to extra virgin olive oil. On the other hand, the reference pediculicide (licid) revealed only mortality rate of 93.3%. On the contrary, no mortalities were recorded in the control group exposed to distilled water. By SEM examination, control lice preserved outer smooth architecture, eyes, antenna, respiratory spiracles, sensory hairs, and legs with hook-like claws. In contrast, dead lice which had been exposed to pediculicidal products showed damage of outer smooth architecture, sensory hairs, respiratory spiracles and/or clinching claws according to pediculicidal products used.

Composition and repellency of the essential oils of Evodia calcicola Chun ex Huang and Evodia trichotoma (Lour.) Pierre against three stored product insects.

During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oils of Evodia calcicola and Evodia trichotoma leaves were found to possess strong repellency against the red flour beetle Tribolium castaneum adults, the cigarette beetle Lasioderma serricorne adults and the booklouse Liposcelis bostrychophila. The two essential oils obtained by hydrodistillation were investigated by GC-MS. The main components of E. calcicola essential oil were identified to be (-)-ß-pinene (44.02%), ß-phellandrene (20.93%), ocimene (16.49%), and D-limonene (9.87%). While the main components of the essential oil of E. trichotoma were D-limonene (69.55%), 1R-a-pinene (11.48%), caryophyllene (2.80%) and spathulenol (2.24%). Data showed that T. castaneum was the most sensitive than other two stored product insects. Compared with the positive control, DEET (N, N-diethyl-3- methylbenzamide), the two essential oils showed the same level repellency against the red flour beetle. However, the essential oil of E. trichotoma showed the same level repellency against the cigarette beetle, while E. calcicola essential oil possessed the less level repellency against L. serricorne, relative to the positive control, DEET. Moreover, the two crude oils also exhibited strong repellency against L. bostrychophila, but lesser level repellency than the positive control, DEET. Thus, the essential oils of E. calcicola and E. trichotoma may be potential to be developed as a new natural repellent in the control of stored product insects.

Efficacy of herbal shampoo base on native plant against head lice (Pediculus humanus capitis De Geer, Pediculidae: Phthiraptera) in vitro and in vivo in Thailand.

Head lice infestation (or pediculosis) is an important public health problem in Thailand, especially in children between the ages 5 and 11 years. Head lice resistance is increasing, chemical pediculicides have lost their efficacy, and, therefore, alternative pediculicides such as herbal shampoos have been proposed to treat head lice infestation. Thus, the present study investigated the efficacy of three herbal shampoos based on native plants in Thailand (Acorus calamus Linn., Phyllanthus emblica Linn., and Zanthoxylum limonella Alston) against head lice and compared them with carbaryl shampoo (Hafif shampoo, 0.6% w/v carbaryl), malathion shampoo (A-Lice shampoo, 1.0% w/v malathion), and commercial shampoos (Babi Mild Natural' N Mild and Johnson's baby shampoo) in order to assess their in vitro and in vivo efficacy. For in vitro study, doses of 0.12 and 0.25 ml/cm(2) of each herbal shampoo were applied to filter paper, then 10 head lice were place on the filter paper. The mortalities of head lice were recorded at 5, 15, 30, and 60 min. The results revealed that all herbal shampoo were more effective on pediculicidal activity than chemical and commercial shampoos with 100% mortality at 15 min; LT50 values ranged from 0.25 to 1.90 min. Meanwhile, chemical shampoos caused 20-80% mortality, and LT50 values ranged from 6.50 to 85.43 min. On the other side, commercial shampoos showed 4.0% mortality. The most effective pediculicide was Z. limonella shampoo, followed by A. calamus shampoo, P. emblica shampoo, carbaryl shampoo, malathion shampoo, and commercial shampoo, respectively. In vivo results showed that all herbal shampoos were also more effective for head lice treatment than chemical and commercial shampoos with 94.67-97.68% of cure rate after the first treatment; the second treatment, 7 days later, revealed that the cure rate was 100%. Meanwhile, chemical shampoo showed 71.67-93.0% of cure rate and, unfortunately, commercial shampoos were nontoxic to head lice and showed 0% of cure rate after the first and the second treatments. Our data showed that three herbal shampoos of native plants in Thailand in this study are suitable to be used as pediculicides for Thai children since it is safe for children and there is no side-effect after application.

The efficacy and safety of alphacypermethrin as a pour-on treatment for water buffalo (Bubalus bubalis) infested with Haematopinus tuberculatus (Phthiraptera: Haematopinidae).

The sucking louse Haematopinus tuberculatus (Burmeister 1839) is an ectoparasite of buffaloes, cattle, camels, and American bison. Alphacypermethrin (ACYP) is a pyrethroid insecticide commonly used to control arthropods of veterinary and public health interest. Therapeutics, such as antiparasitic compounds, is often administered to buffaloes based on dosage and intervals recommended for cattle because very few drugs have buffalo-specific label indications. A trial was conducted on 20 louse-infested buffaloes at a farm to assess the efficacy and safety of ACYP pour-on, at the manufacturer's recommended dose for cattle, on buffaloes naturally infested by H. tuberculatus. Ten animals were assigned to ACYP-treated group (ACYP-group) and ten to untreated control group (C-group). On day 0, all ACYP-group buffaloes received alphacypermethrin pour-on. Louse counts were performed on days -1, 7, 14, 21, 28, 35, 42, 49, and 56 at eight predilection sites on the skin of each buffalo. ACYP was completely effective (100%) at day 7, highly effective (99.8%) at day 14, and completely effective (100%) from day 21 until the end of the study (day 56 post-treatment). During the trial, ACYP was well tolerated by all animals as there were no observed clinically adverse reactions. The results of this trial suggest that ACYP is an effective, safe, and user-friendly compound suitable for treatment of buffaloes with natural louse infestations.

Biting and bloodsucking lice of dogs--treatment by means of a neem seed extract (MiteStop®, Wash Away Dog).

Dogs infested with lice belonging either to the group of Mallophaga (hairlings, i.e., Trichodectes canis) or Anoplura (bloodsucking lice, e.g., Linognathus setosus) were washed with the neem seed preparations MiteStop® or Wash Away Dog. It was found that a single treatment with one of these products killed both motile stages and those developing inside eggs (nits) being glued at the hair. In both cases the product had been left for 20 min onto the hair before it was washed away just with normal tap water.

A Case of Phthiriasis Palpebrarum Treated with Tea Tree Oil in a Child

PURPOSE: The authors of the present study report a case of phthiriasis palpebrarum treated with petrolatum ointment and tea tree oil in a 12-month-old boy. CASE SUMMARY: A bluish-gray macule and blood clots were found on the central portion of the upper eyelid of a boy who had rubbed his eyelid vigorously 1 week prior. Several 0.5 mm sized brownish-gray nits and 1.6 mm sized lice on the eyelashes were visible and was diagnosed with phthiriasis palpebrarum after light microscopic examination. The nits and lice were gently removed mechanically with the help of a white petrolatum ointment (Vaseline) and the eyelashes were cleaned with 50% tea tree oil. Nits and lice were successfully eradicated without recurrence 10 days after daily treatment with petrolatum ointment and 10% tea tree oil eyelash cleansing.

In vitro screening of anti-lice activity of Pongamia pinnata leaves.

Growing patterns of pediculocidal drug resistance towards head louse laid the foundation for research in exploring novel anti-lice agents from medicinal plants. In the present study, various extracts of Pongamia pinnata leaves were tested against the head louse Pediculus humanus capitis. A filter paper diffusion method was conducted for determining the potential pediculocidal and ovicidal activity of chloroform, petroleum ether, methanol, and water extracts of P. pinnata leaves. The findings revealed that petroleum ether extracts possess excellent anti-lice activity with values ranging between 50.3% and 100% where as chloroform and methanol extracts showed moderate pediculocidal effects. The chloroform and methanol extracts were also successful in inhibiting nymph emergence and the petroleum ether extract was the most effective with a complete inhibition of emergence. Water extract was devoid of both pediculocidal and ovicidal activities. All the results were well comparable with benzoyl benzoate (25% w/v). These results showed the prospect of using P. pinnata leave extracts against P. humanus capitis in difficult situations of emergence of resistance to synthetic anti-lice agents.

In Vitro Screening of Anti-lice Activity of Pongamia pinnata Leaves

Growing patterns of pediculocidal drug resistance towards head louse laid the foundation for research in exploring novel anti-lice agents from medicinal plants. In the present study, various extracts of Pongamia pinnata leaves were tested against the head louse Pediculus humanus capitis. A filter paper diffusion method was conducted for determining the potential pediculocidal and ovicidal activity of chloroform, petroleum ether, methanol, and water extracts of P. pinnata leaves. The findings revealed that petroleum ether extracts possess excellent anti-lice activity with values ranging between 50.3% and 100% where as chloroform and methanol extracts showed moderate pediculocidal effects. The chloroform and methanol extracts were also successful in inhibiting nymph emergence and the petroleum ether extract was the most effective with a complete inhibition of emergence. Water extract was devoid of both pediculocidal and ovicidal activities. All the results were well comparable with benzoyl benzoate (25% w/v). These results showed the prospect of using P. pinnata leave extracts against P. humanus capitis in difficult situations of emergence of resistance to synthetic anti-lice agents.

Pediculosis de la cabeza / No disponible

En nuestra experiencia, las infestaciones por piojos de la cabeza son ahora más frecuentes y difíciles de tratar que años atrás. Probablemente se debe al incremento de resistencias a los insecticidas clásicos, documentado en muchos países1,2. Pueden influir otros factores, como la falta de estudios clínicos que avalen las pautas de aplicación y resultados de muchos de los productos comercializados en España, y la falta de control médico sobre el diagnóstico y tratamiento. Nuestros objetivos son: 1. Revisar la biología del parásito, especialmente los aspectos de mayor utilidad para el tratamiento. 2. Actualizar el tratamiento. 3. Recopilar los productos comercializados en España

Head lice infestations are, in our experience, more frequent and difficult to treat today than in the past. This is probably due to the increasing resistance to classical insecticides, documented in many countries1,2. Other factors can also be of influence, such as the lack of clinical studies validating the application guidelines and the results of many of the products sold in Spain, and the lack of medical control on diagnosis and treatment. Our objectives are to: 1. Review the biology of the parasite, especially the aspects of greatest utility for the treatment. 2. Update treatments. 3. To compile the products sold in Spain

Anticholinesterase and pediculicidal activities of monoterpenoids.

The repetitive and inadequate application of pediculicidal products frequently results in the development of resistance to these compounds. Essential oils are a promising alternative to synthetic insecticides, although their mode of action remains to be explored. It has been proposed that one possible target of the essential oils is the inhibition of acetylcholinesterase (AChE). The role of monoterpenoids as possible AChE inhibitors and their relationship with the toxicity was investigated both in vitro and in vivo. Inhibition of electric eel AChE activity showed that the most effective inhibitor was 1,8-cineole with IC(50) 6 x 10(-3) M. The inhibition of AChE activity of head louse homogenate by 1,8-cineole showed IC(50) 7.7 x 10(-2) M. The intoxication symptoms of head lice exposed to vapors of 1,8-cineole was recorded before the in vivo head louse AChE inhibition assay. No correlation was found between neurotoxic symptoms and inhibition of AChE activity.

Impact of the botanical insecticide Neem Azal on survival and reproduction of the biting louse Damalinia limbata on angora goats.

Secondary metabolites present in the neem tree (Azadirachta indica A. Juss, Meliaceae), exhibit a wide range of biological activities in insects. However, few studies have been undertaken to assess the potential of neem products as insecticides for the control of ectoparasites of domestic animals. This study was undertaken to estimate the efficacy of Neem Azal, an azadirachtin-rich extract of neem seeds, in controlling Damalinia limbata (Phthiraptera) louse infestation of angora goats. The study was conducted on a fibre animal farm situated in Central Italy. Groups of 11-12 goats were treated with Neem Azal at an azadirachtin concentration of 650ppm or 125ppm, with Neguvon or were left untreated. Their louse burden was assessed fortnightly to monthly for 22 weeks. A reduction in louse densities of 76-96% was observed from week 2 to week 18 after treatment with the neem solution containing azadirachtin at a concentration of 650ppm. At the lower test concentration (125ppm) a reduction of 60-92% could be recorded from week 2 to week 14. Neem Azal was found to reduce the survival of both adult and nymph stages of D. limbata and to interfere with oviposition and oogenesis of female lice. A decrease in oviposition was observed in neem exposed female lice and the examination of their ovaries revealed morphological alterations in both vitellogenic and previtellogenic ovarioles at the follicular and germinal level. Since neem compounds target different life stages and physiological processes of D. limbata, the development of insecticide resistance by biting lice exposed to neem-based insecticides appears unlikely. For this reason and for its prolonged activity, which in principle allows angora goats to be protected for a large part of the mohair production cycle, neem-based insecticides may have a potential interest for mohair producing breeders.

A new shampoo based on neem (Azadirachta indica) is highly effective against head lice in vitro.

Because topical compounds based on insecticidal chemicals are the mainstay of head lice treatment, but resistance is increasing, alternatives, such as herbs and oils are being sold to treat head lice. To test a commercial shampoo based on seed extract of Azadirachta indica (neem tree) for its in vitro effect, head lice (n=17) were collected from school children in Australia and immersed in Wash-Away Louse shampoo (Alpha-Biocare GmbH, Germany). Vitality was evaluated for more than 3 h by examination under a dissecting microscope. Positive and negative controls were a commercially available head lice treatment containing permethrin 1% (n=19) and no treatment (n=14). All lice treated with the neem shampoo did not show any vital signs from the initial examination after immersion at 5-30 min; after 3 h, only a single louse showed minor signs of life, indicated by gut movements, a mortality of 94%. In the permethrin group, mortality was 20% at 5 min, 50% at 15 min, and 74% after 3 h. All 14 head lice of the negative control group survived during the observation period. Our data show that Wash-Away Louse is highly effective in vitro against head lice. The neem shampoo was more effective than the permethrin-based product. We speculate that complex plant-based compounds will replace the well-defined chemical pediculicides if resistance to the commonly used products further increases.

[Reflection of the problem of pediculosis and its prevention in verbal folk art (according to the materials available in Russian verbal folk art)].

The paper analyzes different forms of oral folk art, dealing with the problem of lice and pediculosis, which were collected by V.I. Dal and given in his two-volume collected works "Proverbs of the Russian people".

Development of a paw paw herbal shampoo for the removal of head lice.

The development and clinical testing of an herbal lice removal shampoo, containing a standardized extract of paw paw, thymol, and tea tree oil, are described. All of these ingredients were selected for their ability to deplete adenosine triphosphate (ATP) levels and, thus, prevent ATP-dependent pesticide resistance. Optimum concentrations of the ingredients, treatment times, and dosing schedules were established through in vitro tests with head lice. In addition to pilot studies involving 21 participants, a final clinical trial, using the optimum shampoo formulation in 16 participants, demonstrated 100% effectiveness in removing head lice and nits.