Bartonella quintana in body lice and head lice from homeless persons, San Francisco, California, USA

Prevalence and associated factors of head lice infestation among primary school children in low- and middle-income countries: systematic review and meta-analysis

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.

Bartonella quintana detection among arthropods and their hosts: a systematic review and meta-analysis

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.

Body Louse Pathogen Surveillance among Persons Experiencing Homelessness, Canada, 2020-2021

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.

The Use of Rabbits Used to Propagate Human Lice for Research

The globally important human diseases of trench fever, epidemic typhus, and relapsing fever are vectored by the human louse Pediculus humanus humanus. Although these conditions are epidemically quiescent at present, they persist in socially dysfunctional situations of war, deprivation, and crowding. The taxonomically closely related head louse, Pediculus humanus capitis, does not respect economic or social status and is quite common in most countries. The 2 types of lice are now recognized as conspecific ecotypes of a single species. While the body louse has been adapted for propagation in the laboratory by feeding in vivo on live rabbits, a similar animal model has not been developed for the host-specific head louse. Accordingly, research for treatment and control of the head louse has largely been performed by using laboratory-reared body lice. This review describes methods for the propagation of body lice in the laboratory and outlines at least 4 areas of research that require sufficient numbers of aged body louse cohorts produced in rabbits for use in controlled studies: 1) pediculicide development and resistance, 2) immunity and vaccine potential, 3) endosymbiotic bacteria needed by lice for nutrition, and 4) lice as vectors of human disease. The review concludes with a discussion of several ethical issues involved with the standard method of using unsedated rabbits and recommends consideration of providing sedating anesthetics for rabbits used in louse feeding procedures.

Eutrichophilus cordiceps Mjöberg, 1910 (Ischnocera: Trichodectidae) in Spiny Tree Porcupines (Coendou villosus): New locality records and the first molecular evidence of association with Bartonella sp

The chewing louse genus Eutrichophilus Mjöberg has 19 species only associated with porcupines (Rodentia: Erethizontidae). Of these species, E. cercolabes, E. cordiceps, E. emersoni, E. minor, E. moojeni, and E. paraguayensis have been recorded in Brazil. In the present study, we report E. cordiceps for the first time in the São Paulo State (Bauru Municipality) and for the second time in the Santa Catarina State (Lages Municipality), providing scanning electron images and light microscopy for the eggs, as well as the first molecular data (18S rRNA) for the genus. Additionally, Bartonella sp. was detected for the first time in this chewing lice species.

Infectious Diseases Among People Experiencing Homelessness: A Systematic Review of the Literature in the United States and Canada, 2003-2022

Homelessness increases the risk of acquiring an infectious disease. We conducted a systematic review of the literature to identify quantitative data related to infectious diseases and homelessness. We searched Google Scholar, PubMed, and SCOPUS for quantitative literature published from January 2003 through December 2022 in English from the United States and Canada. We excluded literature on vaccine-preventable diseases and HIV because these diseases were recently reviewed. Of the 250 articles that met inclusion criteria, more than half were on hepatitis C virus or Mycobacterium tuberculosis. Other articles were on COVID-19, respiratory syncytial virus, Staphylococcus aureus, group A Streptococcus, mpox (formerly monkeypox), 5 sexually transmitted infections, and gastrointestinal or vectorborne pathogens. Most studies showed higher prevalence, incidence, or measures of risk for infectious diseases among people experiencing homelessness as compared with people who are housed or the general population. Although having increased published data that quantify the infectious disease risks of homelessness is encouraging, many pathogens that are known to affect people globally who are not housed have not been evaluated in the United States or Canada. Future studies should focus on additional pathogens and factors leading to a disproportionately high incidence and prevalence of infectious diseases among people experiencing homelessness.

Molecular detection of Bartonella quintana, Acinetobacter baumannii and Acinetobacter haemolyticus in Pediculus humanus lice in Nigeria, West Africa

The human lice Pediculus humanus is distributed worldwide but, it thrives and flourishes under conflict situations where people are forced to live in crowded unhygienic conditions. Molecular methods were used to identify and screen human lice for the DNA of pathogens of public health importance in an area that has been under insurgency related to religious and political conflicts with tens of thousands of internally displaced people (IDP). DNA of Bartonella quintana, Acinetobacter baumannii and Acinetobacter haemolyticus was detected in 18.3%, 40.0% and 1.7%, respectively, of human lice collected from children in Maiduguri, Nigeria. More body lice than head lice were positive for pathogen's DNA (64.3% vs. 44.4%; χ2  = 1.3, p = 0.33), but the difference was not significant. Two lice samples were found to harbour mixed DNA of B. quintana and A. baumannii. Phylogenetic analysis of the cytochrome b (cytb) gene sequences of the positive lice specimens placed them into clades A and E. This is the first report on the molecular identification of human lice and the detection of the DNA of pathogens of public health importance in lice in Nigeria, West Africa. The findings of this study will assist policy makers and medical practitioners in formulating a holistic healthcare delivery to IDPs.

POPULATION STRUCTURE AND BARTONELLA QUINTANA IN HEAD AND BODY LICE IN POKHARA, NEPAL (ANOPLURA: PEDICULIDAE)

This study examined the population structure of head and body lice infesting a random sample of people in Pokhara, Nepal during 2003, 2004, and 2005. A total of 106 participants (6 to 72 yr old, median = 12) volunteered to have lice collected from their heads and clothing. Most participants (70%) harbored only head lice, some (15%) had only body lice, and some (15%) had concurrent infestations of head and body lice (dual infestations). A total of 1,472 lice was collected. Significantly more nymphs were collected than adult lice. Louse populations were generally small (geometric mean = 8.8 lice per person) but a few participants harbored larger louse populations (maximum = 65 lice). People with dual infestations harbored significantly more lice than people with single infestations; however, there was no difference in the infestation intensities between people infested with head lice only vs. those infested with body lice only. Male participants harbored significantly more lice than did females. There were no significant differences in infestation intensity due to participant age or their socioeconomic level. The sex ratio of adult lice was increasingly female biased with increasing adult louse density. Infection of lice with Bartonella quintana was low (ca. 1.5%). Pediculosis is a common problem in urban Nepal.

Head lice as vectors of pathogenic microorganisms

Body lice and head lice are the most common ectoparasites of humans. Head lice (Pediculus humanus capitis) occur worldwide in children and their caretakers, irrespective of their social status. In contrast, body lice (Pediculus humanus corporis) are confined to marginalized population groups in countries of the Global South, homeless people, and refugees. Body lice are known to transmit an array of bacterial pathogens, such as R. prowazekii, R. rickettsii, C. burneti, B. quintana, B. recurrentis, and Y. pestis. The vector capacity of head lice is still a matter of debate. The objective of the review was to scrutinize the existing evidence on the vector capacity of head lice for the transmission of bacterial pathogens. The PUBMED database was searched using a combination of the terms "pediculus humanus" OR "body lice" OR "head lice" AND "pathogen" OR "Rickettsia prowazekii" OR "Bartonella quintana" OR "Borrelia recurrentis" OR "Coxiella burneti" without a time limit. Data from epidemiological studies as well as historical observations demonstrate that body lice and head lice can carry the same array of pathogens. Since the presence of a bacterial pathogen in an arthropod is not sufficient to state that it can be transmitted to humans, and since experimental models are lacking, as yet one cannot conclude with certainty that head lice serve as vectors, although this review presents circumstantial evidence that they do. Adequately designed experimental and epidemiological studies are needed to ascertain the exact transmission potential of head lice.

Emerging bacterial infectious diseases/pathogens vectored by human lice

Human lice have always been a major public health concern due to their vector capacity for louse-borne infectious diseases, like trench fever, louse-borne relapsing fever, and epidemic fever, which are caused by Bartonella quintana, Borrelia recurrentis, and Rickettsia prowazekii, respectively. Those diseases are currently re-emerging in the regions of poor hygiene, social poverty, or wars with life-threatening consequences. These louse-borne diseases have also caused outbreaks among populations in jails and refugee camps. In addition, antibodies and DNAs to those pathogens have been steadily detected in homeless populations. Importantly, more bacterial pathogens have been detected in human lice, and some have been transmitted by human lice in laboratories. Here, we provide a comprehensive review and update on louse-borne infectious diseases/bacterial pathogens.

Increased Risk of Surgical Field Contamination from Acute Pre-operative Treatment of Pediculosis Capitis (Lice) Infestation - A Case Report of Two Twin Pediatric Patients

Introduction

Little is known about the perioperative management of Pediculus capitis (lice) infestations, including risk of contamination to the sterile field, whether to delay surgery, and optimal time to treat and/or operate.

Case Report

Two identical twin patients presented for elective in situ percutaneous pinning of chronic slipped capital femoral epiphyses. Active pediculosis capitis was noted intraoperatively by the anesthesia team during the first patient's surgery. Meticulous examination of the sterile field at that time demonstrated no organisms or other sources of contamination. The second patient's surgery was delayed to discuss her case with the infectious disease team. Scant literature exists to guide recommendations. Ultimately, a single permethrin treatment immediately before surgery was recommended and followed by our team. After careful prepping and draping, a louse was observed on the sterile field near the planned pin insertion site. The case was immediately canceled and delayed indefinitely. After two additional treatments over the next 4 days, only eggs (but no active insects) were observed in the patient's hair. We elected to proceed to surgery at that time, which concluded without issue.

Conclusion

The surgical implications of an active lice infestation are numerous. Administration of antiparasitic medication in the immediate pre-operative period causes increased movement in pediculosis capitis, which may increase risk of sterile field contamination. Elective procedures should be postponed to complete multiple rounds of permethrin. In cases of urgent/emergent surgery, or in which treatment delay is unfeasible, foregoing delousing treatment in the immediate pre-operative period may be recommended.

Water, Sanitation, and Hygiene (WaSH) insecurity in unhoused communities of Los Angeles, California

BACKGROUND

Access to water and sanitation is a basic human right; however, in many parts of the world, communities experience water, sanitation, and hygiene (WaSH) insecurity. While WaSH insecurity is prevalent in many low and middle-income countries, it is also a problem in high-income countries, like the United States, as is evident in vulnerable populations, including people experiencing homelessness. Limited knowledge exists about the coping strategies unhoused people use to access WaSH services. This study, therefore, examines WaSH access among unhoused communities in Los Angeles, California, a city with the second-highest count of unhoused people across the nation.

METHODS

We conducted a cross-sectional study using a snowball sampling technique with 263 unhoused people living in Skid Row, Los Angeles. We calculated frequencies and used multivariable models to describe (1) how unhoused communities cope and gain access to WaSH services in different places, and (2) what individual-level factors contribute to unhoused people's ability to access WaSH services.

RESULTS

Our findings reveal that access to WaSH services for unhoused communities in Los Angeles is most difficult at night. Reduced access to overnight sanitation resulted in 19% of the sample population using buckets inside their tents and 28% openly defecating in public spaces. Bottled water and public taps are the primary drinking water source, but 6% of the sample reported obtaining water from fire hydrants, and 50% of the population stores water for night use. Unhoused people also had limited access to water and soap for hand hygiene throughout the day, with 17% of the sample relying on hand sanitizer to clean their hands. Shower and laundry access were among the most limited services available, and reduced people's ability to maintain body hygiene practices and limited employment opportunities. Our regression models suggest that WaSH access is not homogenous among the unhoused. Community differences exist; the odds of having difficulty accessing sanitation services is two times greater for those living outside of Skid Row (Adj OR: 2.52; 95% CI: 1.08-6.37) and three times greater for people who have been unhoused for more than six years compared to people who have been unhoused for less than a year (Adj OR: 3.26; 95% CI: 1.36-8.07).

CONCLUSION

Overall, this study suggests a need for more permanent, 24-h access to WaSH services for unhoused communities living in Skid Row, including toilets, drinking water, water and soap for hand hygiene, showers, and laundry services.

Prevalence and Genetic Diversity of Bartonella Spp. in Northern Bats (Eptesicus nilssonii) and Their Blood-Sucking Ectoparasites in Hokkaido, Japan

We investigated the prevalence of Bartonella in 123 northern bats (Eptesicus nilssonii) and their ectoparasites from Hokkaido, Japan. A total of 174 bat fleas (Ischnopsyllus needhami) and two bat bugs (Cimex japonicus) were collected from the bats. Bartonella bacteria were isolated from 32 (26.0%) of 123 bats. Though Bartonella DNA was detected in 79 (45.4%) of the bat fleas, the bacterium was isolated from only one bat flea (0.6%). The gltA sequences of the isolates were categorized into genotypes I, II, and III, which were found in both bats and their fleas. The gltA sequences of genotypes I and II showed 97.6% similarity with Bartonella strains from a Finnish E. nilssonii and a bat flea from a E. serotinus in the Netherlands. The rpoB sequences of the genotypes showed 98.9% similarity with Bartonella strain 44722 from E. serotinus in Republic of Georgia. The gltA and rpoB sequences of genotype III showed 95.9% and 96.7% similarity with Bartonella strains detected in shrews in Kenya and France, respectively. Phylogenetic analysis revealed that Bartonella isolates of genotypes I and II clustered with Bartonella strains from Eptesicus bats in Republic of Georgia and Finland, Myotis bats in Romania and the UK, and a bat flea from an Eptesicus bat in Finland. In contrast, genotype III formed a clade with B. florencae, B. acomydis, and B. birtlesii. These data suggest that northern bats in Japan harbor two Bartonella species and the bat flea serves as a potential vector of Bartonella transmission among the bats.

Factors Associated With Hospital Readmission Among Patients Experiencing Homelessness

INTRODUCTION

Homelessness is associated with increased acute care utilization and poor healthcare outcomes. This study aims to compare hospital readmission rates among patients experiencing homelessness and patients who are not homeless and assess the impact of different clinical and demographic characteristics on acute care utilization among patients experiencing homelessness.

METHODS

This was a retrospective study of patients encountered in 2018 and 2019 at ChristianaCare Health Systems. The analysis was done in August 2021. The prevalence of major chronic conditions among patients experiencing homelessness (n=1,329) and those not experiencing it (n=143,360) was evaluated. Patients experiencing homelessness were matched with nonhomeless patients using 1:1 propensity score matching. Time-to-event analysis approaches were used to analyze time-to-readmission and 30-day readmission rates.

RESULTS

The 30-day readmission rates were 42.8% among patients experiencing homelessness and 19.9% among matched patients not experiencing homelessness. The hazard of 30-day readmission among patients experiencing homelessness was 2.6 (95% CI=1.93, 3.53) times higher than that among the matched nonhomeless cohort. In patients experiencing homelessness, drug use disorder, major depressive disorder, chronic kidney disease, obesity, arthritis, HIV/AIDS, and epilepsy were associated with shortened time to readmission. Moreover, Black racial identity was associated with shortened time to readmission.

CONCLUSIONS

Patients experiencing homelessness had higher acute care utilization than those not experiencing homelessness. Black racial identity and several comorbidities were associated with increased acute care utilization among patients experiencing homelessness. Efforts to address upstream social determinants of health, destigmatization, and healthcare management accounting for the whole spectrum of clinical comorbidities might be important in promoting the health of people experiencing homelessness.

Body Lice among People Experiencing Homelessness and Access to Hygiene Services during the COVID-19 Pandemic-Preventing Trench Fever in Denver, Colorado, 2020

Eight people with human body louse-borne Bartonella quintana infections were detected among people experiencing homelessness (PEH) in Denver during January-September 2020, prompting a public health investigation and community outreach. Public health officials conducted in-person interviews with PEH to more fully quantify body lice prevalence, transmission risk factors, access to PEH resources, and how the COVID-19 pandemic has affected resource access. Recent body lice exposure was reported by 35% of 153 interview participants. In total, 75% of participants reported reduced access to PEH services, including essential hygiene activities to prevent body lice, during Colorado's COVID-19 stay-at-home orders. Future pandemic planning should consider hygiene resource allocation for PEH populations to prevent emerging and reemerging infections such as B. quintana.

A Review of Bartonella Infections in California-Implications for Public and Veterinary Health

Bartonella are vector-transmitted, intracellular bacteria that infect a wide variety of blood-feeding arthropods and their vertebrate hosts. In California, more than 13 species of Bartonella have been described from companion animals, livestock, and wildlife, of which four have been associated with human disease. Infections in humans cause a range of symptoms from relatively mild to severe, especially in immunocompromised individuals. Exposure to infected domestic animals and wildlife, and their ectoparasites, may increase the risk of cross-species transmission. The objective of this review was to compile and summarize published materials on human and animal Bartonella infections in California. Medical and veterinary case reports of bartonellosis were highlighted in an effort to increase the awareness of this poorly understood and potentially under-recognized disease among healthcare professionals and veterinarians.

First exploratory study of bacterial pathogens and endosymbionts in head lice from a Mayan community in southern Mexico

Lice represent one of the most neglected group of vectors worldwide, particularly in Latin America. Records of bacterial agents related to head lice are non-existent in this region of the continent. Many of these communities often do not have adequate access to public services and/or health protection. The normalization of this condition prevents them from manifesting discomfort, such as bites and itching, which further aggravates the situation, as they can be vectors of important diseases. For this reason, the aim of this work was to identify the richness of bacterial pathogens (Acinetobacter, Bartonella, and Rickettsia) and endosymbionts (Wolbachia) in head lice of paediatric patients from the indigenous municipality of Hoctun, Yucatan, Mexico. DNA extraction was performed using the QIAamp DNA Mini Kit. For the detection of bacterial pathogens, fragments of the gltA, rpoB, and 16S rDNA genes were amplified. For the detection of Wolbachia, the wsp gene was amplified. Of the 28 lice analysed, the presence of two genera of bacterial pathogens was detected Acinetobacter (42.9% = 12/28) and Bartonella (7.14% = 2/28). We also detected the endosymbiont Wolbachia (71.42% = 20/28). Our results showed that DNA from three bacteria species (Acinetobacter baumannii, Bartonella quintana, and Wolbachia pipientis) was present with frequencies ranging from 3.57% to 71.42%. This work represents the first exploratory study of the diversity of agents associated with head lice (Pediculus humanus capitis) in Mexico and Latin America. Due to the findings generated in the present study, it is important to perform surveillance of head lice populations to identify the degree of spread of these pathogens and their impact on populations in the region.

Serologic study of Bartonella sp. infection among human population of Southern Spain

INTRODUCTION

The purpose of this study was to determine the prevalence of IgG antibodies against Bartonella sp. in a randomly selected sample from the population of the patients of North Sanitary District of Jaén.

METHODS

We used a commercially available immunofluorescent test (Focus-Technology IFA Bartonella quintana and B. henselae test).

RESULTS

Six hundred five healthy individuals were divided by sex into three age groups. We detected that 13.55% and 11.07% subjects were IgG seropositive to B. henselae and B. quintana, respectively.

CONCLUSIONS

Our data show that the prevalence of both Bartonella species in Andalusia (Southern Spain) is relatively high. No statistical difference in the seropositivity was observed among these groups. In both cases, the IgG antibody titers ranged from 1/128 to 1/512.

New chemistries for the control of human head lice, Pediculus humanus capitis: A mini-review

Pediculus lice represent one of the longest and most prevalent parasitic infestations of humans. Head lice are an economic and social concern whereas body lice pose a more serious public health threat. Significant progress has been made in the study of human lice over the last 10 years, allowing for new approaches in their control. An in vitro rearing system has made it possible to maintain insecticide-susceptible and -resistant reference strains, which allowed an in depth study of pediculicide resistance, including its underlying molecular mechanisms and the detection and monitoring of resistance. The generation of inbreed strains facilitated the efficient sequencing, assembly and annotation of the genomes and transcriptomes of both lice. The use of functional genomics and reverse genetics elucidated the genetics involved in the evolution of resistance and the discovery of novel target sites for the development of new pediculicides. In this review, four new effective pediculicide products, each with different mode of action and unique chemistries, will be presented. They have been found to be safe and selective, and control resistant lice. As such, they meet the criteria necessary to be used in rotations as a sustainable resistance management strategy.

Molecular Monitoring of Knockdown Resistance in Head Louse (Phthiraptera: Pediculidae) Populations in Iran

Knockdown resistance (kdr) is a common mechanism of insecticide resistance in head lice to the conventionally used pyrethroid pediculosis and can be the result of various amino acid substitutions within the voltage-sensitive sodium channel (VSSC). In this study, 54 sequences from varied specimens were investigated to monitor well-known resistance mutations and probable new mutations. The Pediculus humanus capitis de Geer specimens were collected from 13 provinces in Iran. The specimens were stored in 70% ethanol until DNA extraction and PCR amplification of ~900-bp fragment of VSSC. The sequences were analyzed using different bioinformatics software for the detection of well-known kdr substitutions and additional mutations potentially associated with kdr resistance in head lice. There were six new and an old (haplotype I) kdr haplotypes within the Iranian head louse population. K794E, F815I, and N818D amino acid substitutions were reported for the first time. The P813H mutation was the most prevalent amino acid substitution in eight provinces. Among 53 sequences, 26 (49%) were homozygous susceptible, and 27 (51%) were heterozygotes. Thus, 51% of the head lice collected in Iran harbored only the P813H allele. The exact test for the Hardy-Weinberg (H-W) equilibrium showed that genotype frequencies differed significantly from the expectation in East-Azerbaijan and Tehran provinces. Moreover, these populations had an inbreeding coefficient (Fis) <0, indicating the excess of heterozygotes. This observation suggests that the populations of head lice from Iran are currently under active selective pressure. For the rest of the populations, H-W equilibrium and the expectations were significantly in harmony. The results of the current study highlight molecular techniques in the accurate detection of resistance genotypes before their establishment within the head louse population. Accurate detection of resistant genotypes seems to be helpful in decision-making on lice control programs and resistance monitoring and management.

The Toxicity of Essential Oils From Three Origanum Species Against Head Louse, Pediculus humanus capitis

PURPOSE

Pediculosis caused by human head louse, Pediculus humanus capitis De Geer (Anoplura: Pediculidae) is a public health problem with a high prevalence, especially among children in school age. Different chemical pediculicides (insecticides) are used against lice but the repeated application of these pediculicides for the treatment of P. humanus capitis infestation in the past decades has resulted in the development of resistance. The plant essential oils have been used as alternative sources of lice treatment agents. Pediculicidal activity of the essential oils of three Origanum species (O. onites, O. majorana and O. minutiflorum) against P. humanus capitis adults was examined in this study.

METHODS

Essential oils from aerial parts of three Origanum species were obtained by hydrodistillation using a Clevenger-type apparatus. P. humanus capitis specimens used were obtained from infested children by combing method at primary schools. Adult lice were exposed to three dilutions (1%, 0.5% and 0.1% w/v) of tested oils for 5 min using the adult immersion test.

RESULTS

According to the results, all Origanum essential oils at 1% concentration have been shown to significantly decrease the rate of limb, bowel and abdomen movements, producing more than 90% mortality after 12 h.

CONCLUSION

Our results indicated that Origanum essential oils can be used for the development of new pediculicides against head louse.

Bartonella spp. in Small Mammals and Their Fleas in Differently Structured Habitats From Germany

Most Bartonella spp. are transmitted by fleas and harbored by small mammals which serve as reservoirs. However, little is known about the composition of fleas and their Bartonella spp. from small mammals in Central Europe. Therefore, the aims of this study were to investigate flea communities on small mammals from three differently structured sites (urban, sylvatic, renatured) in Germany as well as the prevalence of Bartonella spp. in small mammals and their parasitizing fleas. In total, 623 small mammals belonging to 10 different species (the majority were Myodes glareolus and Apodemus flavicollis) were available. Fleas were removed from the small mammals' fur, morphologically identified and DNA was extracted. To detect Bartonella spp., two conventional PCRs targeting the gltA gene and the 16S-23S rRNA intergenic spacer were carried out followed by sequencing. Obtained sequences were compared to those in GenBank. In total, 1,156 fleas were collected from 456 small mammals. Altogether, 12 different flea species (the majority were Ctenophthalmus agyrtes, Nosopsyllus fasciatus, and Megabothris turbidus) were detected. At the urban site mostly Leptopsylla segnis and N. fasciatus were collected which may be vectors of zoonotic pathogens to companion animals. The overall prevalence for Bartonella in small mammals was 43.3% and in fleas 49.1%. Five different Bartonella spp. were detected in small mammals namely B. grahamii, B. taylorii, B. doshiae, Bartonella sp. N40 and uncultured Bartonella sp. whereas in fleas four Bartonella spp. were found which were with the exception of B. doshiae identical to the Bartonella species detected in their small mammal hosts. While B. grahamii was the only zoonotic Bartonella sp. most Bartonella strains found in fleas and small mammals belonged to uncultured Bartonella spp. with unknown zoonotic potential. This study showed a high diversity of flea species on small mammals from Germany. Further, high prevalence rates of Bartonella species were detected both in fleas and in their mammalian hosts. Several different Bartonella species with a high genetic variability were discovered. Especially at the urban study sites, this may pose a risk for Bartonella transmission to companion animals and humans.

Serologic study of Bartonella sp. infection among human population of Southern Spain

INTRODUCTION

The purpose of this study was to determine the prevalence of IgG antibodies against Bartonella sp. in a randomly selected sample from the population of the patients of North Sanitary District of Jaén.

METHODS

We used a commercially available immunofluorescent test (Focus-Technology IFA Bartonella quintana and B. henselae test).

RESULTS

Six hundred five healthy individuals were divided by sex into three age groups. We detected that 13.55% and 11.07% subjects were IgG seropositive to B. henselae and B. quintana, respectively.

CONCLUSIONS

Our data show that the prevalence of both Bartonella species in Andalusia (Southern Spain) is relatively high. No statistical difference in the seropositivity was observed among these groups. In both cases, the IgG antibody titers ranged from 1/128 to 1/512.

Molecular identification of head lice collected in Franceville (Gabon) and their associated bacteria

BACKGROUND

Pediculus humanus, which includes two ecotypes (body and head lice), is an obligate bloodsucking parasite that co-evolved with their human hosts over thousands of years, thus providing a valuable source of information to reconstruct the human migration. Pediculosis due to head lice occurred each year throughout the world and several pathogenic bacteria, which are usually associated with body lice, are increasingly detected in them. In Gabon, where this pediculosis is still widespread, there is a lack of data on genetic diversity of head lice and their associated bacteria.

METHODS

This study aimed to investigate the phylogeny of head lice collected in Gabon and their associated bacteria, using molecular tools. Between 26 March and 11 April 2018, 691 head lice were collected from 86 women in Franceville. We studied the genetic diversity of these lice based on the cytochrome b gene, then we screened them for DNA of Bartonella quintana, Borrelia spp., Acinetobacter spp., Yersinia pestis, Rickettsia spp., R. prowazekii, Anaplasma spp. and C. burnetii, using real time or standard PCR and sequencing.

RESULTS

Overall 74.6% of studied lice belonged to Clade A, 25.3% to Clade C and 0.1% to Clade E. The phylogenetic analysis of 344 head lice yielded 45 variable positions defining 13 different haplotypes from which 8 were novel. Bacterial screening revealed the presence of Borrelia spp. DNA in 3 (0.4%) of 691 head lice belonging to Clade A and infesting one individual. This Borrelia is close to B. theileri (GenBank: MN621894). Acinetobacter spp. DNA has been detected in 39 (25%) of the 156 screened lice; of these 13 (8.3%) corresponded to A. baumannii. Acinetobacter nosocomialis (n = 2) and A. pittii (n = 1) were also recorded.

CONCLUSIONS

To of our knowledge, this study is the first to investigate the genetic diversity of head lice from Gabon. It appears that Clade C is the second most important clade in Gabon, after Clade A which is known to have a global distribution. The detection of Borrelia spp. DNA in these lice highlight the potential circulation of these bacteria in Gabon.

Isolation and genetic properties of Bartonella in eastern bent-wing bats (Miniopterus fuliginosus) in Japan

The prevalence and genetic characteristics of Bartonella species in eastern bent-wing bats (Miniopterus fuliginosus) from Japan were investigated. Bartonella bacteria were isolated from 12/50 (24%) of bats examined. Analyses of sequence similarities of the citrate synthase gene (gltA) and RNA polymerase beta-subunit-encoding (rpoB) gene indicated that the isolates from M. fuliginosus were distinct from those present in known Bartonella species as the levels of similarity for both of the genes were lower than the cut-off values for species identification in Bartonella. A phylogenetic analysis of the gltA sequences revealed that the Miniopterus bat-associated strains fell into five genotypes (I to V). Though genotypes I to IV formed a clade with Bartonella from Miniopterus bats from Taiwan, genotype V made a monophyletic clade separate from other bat isolates. In a phylogenetic analysis with the concatenated sequences of the 16S rRNA, gltA, rpoB, cell division protein (ftsZ) gene, and riboflavin synthase gene (ribC), isolates belonging to genotypes I to IV clustered with Bartonella strains from Taiwanese Miniopterus bats, similar to the outcome of the phylogenetic analysis with gltA, whereas genotype V also made a monophyletic clade separate from other bat-associated Bartonella strains. The present study showed that M. fuliginosus in Japan harbor both genus Miniopterus-specific Bartonella suggesting to be specific to the bats in Japan.

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The prevalence of Bartonella in Miniopterus fuliginosus was 24%(12/50).

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M. fuliginosus in Japan harbored two novel Bartonella species in their blood.

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One Bartonella species was the genus Miniopterus-specific Bartonella.

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The other was distinct from other known bat-associated Bartonella.

Genetic Diversity of Pediculus humanus capitis (Phthiraptera: Pediculidae) in Peninsular Malaysia and Molecular Detection of Its Potential Associated Pathogens

Pediculosis capitis caused by Pediculus humanus capitis (De Geer) is endemic all over the world, and children are mostly affected, particularly those living in overcrowded institutions. Several studies have shown that P. h. capitis carried human pathogenic bacteria, suggesting the potential role of head lice in the transmission of pathogens to humans. In this study, we determined the genetic diversity of head lice collected from welfare homes sheltering underprivileged children by using DNA barcoding and demonstrated the presence of Acinetobacter spp., Serratia marcescens, and Staphylococcus aureus in head lice, which have never been investigated before in Malaysia. Cox1 DNA barcoding identified the head lice, P. h. capitis collected from welfare homes across two geographical areas of Peninsular Malaysia as belonging to clades A, B, and D. Acinetobacter bacteria: Acinetobacter guillouiae, Acinetobacter junii, Acinetobacter baumannii, and Acinetobacter nosocomialis were detected in head lice belonging to clades A and also D. In addition, DNA from S. marcescens and S. aureus were also detected in both clades A and D. To our knowledge, this is the first report on the genetic diversity of head lice in Malaysia through DNA barcoding, as well as the first to provide molecular evidence on the type of bacteria occurring in head lice in Malaysia. It is anticipated that the DNA barcoding technique used in this study will be able to provide rapid and accurate identification of arthropods, in particular, medically important ectoparasites.

Pediculosis capitis y transmisión potencial de enfermedades infecciosas reemergentes en Colombia. Revisión de la literatura

Introducción. La infestación por piojos de la cabeza en humanos (Pediculus humanus capitis) se conoce como pediculosis capitis. Estos parásitos pueden ser vectores de enfermedades infecciosas con potencial reemergente.Objetivos. Revisar la literatura actual sobre las enfermedades infecciosas transmitidas por piojos de la cabeza y realizar una breve descripción de sus manifestaciones clínicas.Materiales y métodos. Se realizó una revisión de la literatura en PubMed, ScienceDirect, SciELO y Redalyc mediante la siguiente estrategia de búsqueda: años de publicación: 1938 a 2019; idioma: inglés y español; términos de búsqueda: “Pediculus”, “lice infestations”, “bacteria”, “emerging communicable diseases”, “Rickettsia”, “Bartonella”, “Borrelia”, “Acinetobacter”, “Yersinia“, and “Colombia”, y sus equivalentes en español.Resultados. De los 110 artículos incluidos, la mayoría correspondió a investigaciones originales (48.2%). A nivel mundial, numerosos estudios han reportado la transmisión de Rickettsia prowazekii, Bartonella quintana, Borrelia recurrentis, Staphylococcus aureus, Acinetobacter baumannii y Yersinia pestis, entre otras bacterias, por los piojos de la cabeza y del cuerpo en humanos.Conclusiones. Aunque las enfermedades infecciosas transmitidas por piojos de la cabeza son raras, guardan potencial reemergente en poblaciones afectadas por migraciones humanas, crisis sociopolíticas, indigencia e inmunosupresión. En Colombia no se han realizado investigaciones sobre la transmisión de estas enfermedades por Pediculus spp., por lo que se sugiere que en estudios futuros se determine la prevalencia y los aspectos epidemiológicos de las enfermedades transmitidas por piojos de la cabeza en población colombiana.

Detection of permethrin resistance and phylogenetic clustering of turkish head lice (Pediculus humanus capitis; De Geer, 1767 populations

Head lice infestation caused by Pediculus humanus capitis De Geer, 1767 is one of the most common public health problems. The relationship between humans and head lice dates back millions of years ago that differentiated into different phylogenetic clades. Treatment of head lice infestation usually based on insecticide-based products, which promotes the resistance in the head lice populations. In the present study, we aimed to screen the presence of permethrin resistance among collected P. h. capitis specimens in Turkey. Three mutation sites (T917I, L920F, and M815I) were screened using real-time PCR and resistance was identified by melt analysis. Of the studied specimens, resistance allele frequency (RAF) was found 0.98 for T917I, 0.99 for L920F, and 1.00 for M815I. The phylogenetic study revealed that Clade A and Clade B are present and overlap in Turkey. The present study is first to screen the resistance among Turkish head lice specimens. To not stimulate the pyrethroids resistance in head lice populations, early detection of resistance is crucial and will help the health professionals to choose suitable formula in the treatment. We suggest that the resistance status needs to be screened in randomly selected populations before any treatment application is given.

Bartonella spp. Prevalence (Serology, Culture, and PCR) in Sanitary Workers in La Rioja Spain

Bartonella spp. are increasingly implicated in association with a spectrum of zoonotic infectious diseases. One hundred sanitary workers in La Rioja, Spain completed a questionnaire and provided blood specimens for Bartonella spp. serology and Bartonella alpha-Proteobacteria growth medium (BAPGM) enrichment blood culture/PCR. Six immunofluorescence assays (IFA) were performed and aseptically obtained blood specimens were inoculated into liquid BAPGM and subcultured onto blood agar plates. Bartonella DNA was amplified using conventional and real-time PCR assays. The Bartonella spp., strain, or genotype was determined by DNA sequencing. Bartonella seroreactivity was documented in 83.1% and bloodstream infection in 21.6% of participants. Bartonella henselae, B. vinsonii subsp. berkhoffii genotypes I and III, and B. quintana were identified. IFA seroreactivity and PCR positivity were not statistically associated with self-reported symptoms. Our results suggest that exposure to and non-clinical infection with Bartonella spp. may occur more often than previously suspected in the La Rioja region.

Where Are We With Human Lice? A Review of the Current State of Knowledge

Pediculus humanus is an obligate bloodsucking ectoparasite of human that includes two ecotypes, head louse and body louse, which differ slightly in morphology and biology, but have distinct ecologies. Phylogenetically, they are classified on six mitochondrial clades (A, B, C, D, E, and F), head louse encompasses the full genetic diversity of clades, while body louse belongs to clades A and D. Recent studies suggested that not only body louse, but also head louse can transmit disease, which warrants greater attention as a serious public health problem. The recent sequencing of body louse genome confirmed that P. humanus has the smallest genome of any hemimetabolous insect reported to date, and also revealed numerous interesting characteristics in the nuclear and mitochondrial genomes. The transcriptome analyses showed that body and head lice were almost genetically identical. Indeed, the phenotypic flexibility associated with the emergence of body lice, is probably a result of regulatory changes, perhaps epigenetic in origin, triggered by environmental signals. Current lice control strategies have proven unsuccessful. For instance, ivermectin represents a relatively new and very promising pediculicide. However, ivermectin resistance in the field has begun to be reported. Therefore, novel opportunities for pest control strategies are needed. Our objective here is to review the current state of knowledge on the biology, epidemiology, phylogeny, disease-vector and control of this fascinating and very intimate human parasite.

Bartonella quintana Endocarditis in a Homeless Man with Cat Exposure in San Diego, California

We report a case of Bartonella quintana endocarditis in a homeless man with congenital bicuspid aortic valve and significant cat exposure living in downtown San Diego, California.

Prevalence of zoonotic Bartonella among prairie rodents in Illinois

Bartonella is a genus of gram-negative bacteria that includes a variety of human and veterinary pathogens. These pathogens are transmitted from reservoirs to secondary hosts through the bite of arthropod vectors including lice and fleas. Once in the secondary host, the bacteria cause a variety of pathologies including cat-scratch disease, endocarditis, and myocarditis. Reservoirs of these bacteria are numerous and include several species of large mammals, mesocarnivores, and small mammals. Research on reservoirs of these bacteria has focused on western North America, Europe, and Asia, with little focus on the eastern and central United States. We assessed the prevalence of zoonotic Bartonella species among prairie-dwelling rodent species in the midwestern United States. Tissue samples (n = 700) were collected between 2015 and 2017 from five rodent species and screened for the presence of Bartonella DNA via PCR and sequencing of two loci using Bartonella-specific primers. Bartonella were prevalent among all five species, with 13-lined ground squirrels (Ictidomys tridecemlineatus) serving as a likely reservoir of the pathogen B. washoensis, and other rodents serving as reservoirs of the pathogens B. grahamii and B. vinsonii subsp. arupensis. These results demonstrate the value of studies of disease ecology in grassland systems, particularly in the context of habitat restoration and human–vector interactions.

First Determination of Pyrethroid Knockdown Resistance Alleles in Human Head Lice (Phthiraptera: Pediculidae) From Chile

The infestation with the human ectoparasite, Pediculus humanus capitis (De Geer), is a common public health problem affecting schoolchildren worldwide. In Chile, the main active ingredients present in the over-the-counter pediculicides contain pyrethroids. Despite the extended use of these products, there is no evidence of the insecticide resistance status of the head lice geographically located in Chile. The most extended resistant mechanism of pyrethroids consists of the target site insensitivity (Kdr) determined by the presence of mutations linked to insecticide-binding sites in the voltage-sensitive sodium channel. T917I is recognized as the main mutation in head lice, and detection is considered to be a biomarker of resistance. The goal of the present study was to detect the presence and distribution of T917I mutation in five geographic locations of Chile. All five geographically selected louse populations had a frequency of pyrethroid resistance genes that ranged from 36 to 77%, and 94.9% of the collected head lice had one or two T917I mutant alleles. Moreover, the frequency of the aggregate resistant alleles was 50.5%. This is the first evidence that head lice in Chile had the mutations commonly associated with the resistance to pyrethroids. Moreover, the overrepresentation of heterozygotes in the studied populations suggests that head lice in Chile are currently under active selective pressure.

Changing Demographics and Prevalence of Body Lice among Homeless Persons, Marseille, France

The prevalence of body lice among 2,288 sheltered homeless persons in the city of Marseille during 2000–2017 was 12.2% and significantly decreased over time. We report a positive association between body lice infestations and older age, duration of stays in France for migrants, frequent consumption of alcohol, and tobacco smoking.

Chagas Disease Knowledge and Risk Behaviors of the Homeless Population in Houston, TX

Chagas disease is a parasitic infection, caused by Trypanosoma cruzi, endemic in Latin America. Sylvatic T. cruzi-infected triatomine vectors are present in rural and urban areas in the southern USA and may transmit T. cruzi infection to at-risk populations, such as homeless individuals. Our study aimed to evaluate Chagas disease knowledge and behaviors potentially associated with transmission risk of Chagas disease among Houston, Texas' homeless population by performing interviews with 212 homeless individuals. The majority of the 212 surveyed homeless individuals were male (79%), African-American (43%), American-born individuals (96%). About 30% of the individuals reported having seen triatomines in Houston, and 25% had evidence of blood-borne transmission risk (IV drug use and/or unregulated tattoos). The median total time homeless was significantly associated with recognition of the triatomine vector. Our survey responses indicate that the homeless populations may exhibit potential risks for Chagas disease, due to increased vector exposure, and participation in blood-borne pathogen risk behaviors. Our findings warrant additional research to quantify the prevalence of Chagas disease among homeless populations.

Molecular Survey of Head and Body Lice, Pediculus humanus, in France

Human lice, Pediculus humanus, are obligate blood-sucking parasites. Phylogenetically, they belong to several mitochondrial clades exhibiting some geographic differences. Currently, the body louse is the only recognized disease vector, with the head louse being proposed as an additional vector. In this article, we study the genetic diversity of head and body lice collected from Bobigny, a town located close to Paris (France), and look for louse-borne pathogens. By amplifying and sequencing the cytb gene, we confirmed the presence of clades A and B in France. Besides, by amplifying and sequencing both cytb and cox1 gene, we reported, for the first time, the presence of clade E, which has thus far only been found in lice from West Africa. DNA from Bartonella quintana was detected in 16.7% of body lice from homeless individuals, but in none of the head lice collected from 47 families. Acinetobacter DNA was detected in 11.5% of head lice belonging to all three clades and 29.1% of body lice. Six species of Acinetobacter were identified, including two potential new ones. Acinetobacter baumannii was the most prevalent, followed by Candidatus Acinetobacter Bobigny-1, Acinetobacter calcoaceticus, Acinetobacter nosocomialis, Acinetobacter junii, and Candidatus Acinetobacter Bobigny-2. Body lice were found to be infected only with A. baumannii. These findings show for the first time, the presence of clade E head lice in France. This study is also the first to report the presence of DNAs of several species of Acinetobacter in human head lice in France.

Do drowning and anoxia kill head lice?

Chemical, physical, and mechanical methods are used to control human lice. Attempts have been made to eradicate head lice Pediculus humanus capitis by hot air, soaking in various fluids or asphyxiation using occlusive treatments. In this study, we assessed the maximum time that head lice can survive anoxia (oxygen deprivation) and their ability to survive prolonged water immersion. We also observed the ingress of fluids across louse tracheae and spiracle characteristics contrasting with those described in the literature. We showed that 100% of lice can withstand 8 h of anoxia and 12.2% survived 14 h of anoxia; survival was 48.9% in the untreated control group at 14 h. However, all lice had died following 16 h of anoxia. In contrast, the survival rate of water-immersed lice was significantly higher when compared with non-immersed lice after 6 h (100% vs. 76.6%, p = 0.0037), and 24 h (50.9% vs. 15.9%, p = 0.0003). Although water-immersed lice did not close their spiracles, water did not penetrate into the respiratory system. In contrast, immersion in colored dimeticone/cyclomethicone or colored ethanol resulted in penetration through the spiracles and spreading to the entire respiratory system within 30 min, leading to death in 100% of the lice.

The epidemic typhus and trench fever are risk for public health due to increased migration in southeast of Turkey

Pediculus humanus capitis is a small ectoparasitic insect that has lived and feds on human beings for thousands of years. Molecular techniques have been used for Pediculus species identification and evolutionary, phylogenic, and ecological studies. A total of 23 adults of P. h. capitis were collected in Gaziantep, located in southeast Turkey, and DNA was isolated from all P. h. capitis using DNA extraction kit. All DNA samples were screened for investigate of Ricettsia prowazekii, Bartonella quintana and Borrelia recurrentis with real-time polymerase chain reaction. In addition, we investigated genetic variation in DNA samples of Pediculus humanus capitis using the cytochrome oxidase I genetic DNA sequence. We found 4 (17.4%) Ricettsia prowazekii and 3 (13.1%) Bartonella quintana in DNA samples of Pediculus humanus capitis, while we did not find any Bartonella recurrentis in any of the DNA samples. We demonstrated 1.8% genetic variations in DNA samples of Pediculus humanus capitis with Bartonella quintana. The phylogenetic tree based on the cytochrome oxidase I gene revealed that P. h. capitis in southeast Turkey are classified into two clades (clade A, clade B) and Bartonella quintana was found in only clade B. However, we did not find any genetic variations in other DNA samples in this region. The genetic variations may be related to P. h.capitis vector of Bartonella quintana has found in this study. In addition, this study was shown that P. h. capitis do transmit Rickettsia prowazekii and Bartonella quintana to people, epidemic typhus and trench fever may emergence in Gaziantep southeast of Turkey in the future.

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, was identified in three of the 600 (0.5%) head lice studied. Our study also shows, for the first time, the presence of the DNA of two pathogenic bacteria, namely Coxiella burnetii (5.1%) and Rickettsia aeschlimannii (0.6%), detected in human head lice, as well as the DNA of potential new species from the Anaplasma and Ehrlichia genera of unknown pathogenicity. The finding of several Malian head lice infected with B. quintana, C. burnetii, R. aeschlimannii, Anaplasma and Ehrlichia is alarming and highlights the need for active survey programs to define the public health consequences of the detection of these emerging bacterial pathogens in human head lice.

[Pediculus capitis in schoolchildren of the urban area of Nuevo León, México: Analyses of associated factors]

INTRODUCTION

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.

OBJECTIVE

To determine the prevalence of Pediculus capitis in primary school children and to evaluate risk factors and individual or socioeconomic characteristics statistically associated with infestation.

MATERIALS AND METHODS

We included 840 schoolchildren from six municipalities after parents and children signed an informed consent. Ectoparasites were collected from infested children using a finetoothed comb. Participants were interviewed using a questionnaire on individual and socioeconomic variables including age, gender, education, hair characteristics, overcrowding, and siblings with pediculosis, among others.

RESULTS

The overall prevalence of head lice in schoolchildren was 28% (235/840), the highest prevalence was among girls (33.7%, 140/417), and children from the fifth grade (10-11 years old) were the most affected (6.2%; 52/840). Female gender, long hair and the father's education level were significantly associated with P. capitis.

CONCLUSION

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.

Genotyping ofBartonellabacteria and their animal hosts: current status and perspectives

Growing evidence demonstrates that bacterial species diversity is substantial, and many of these species are pathogenic in some contexts or hosts. At the same time, laboratories and museums have collected valuable animal tissue and ectoparasite samples that may contain substantial novel information on bacterial prevalence and diversity. However, the identification of bacterial species is challenging, partly due to the difficulty in culturing many microbes and the reliance on molecular data. Although the genomics revolution will surely add to our knowledge of bacterial systematics, these approaches are not accessible to all researchers and rely predominantly on cultured isolates. Thus, there is a need for comprehensive molecular analyses capable of accurately genotyping bacteria from animal tissues or ectoparasites using common methods that will facilitate large-scale comparisons of species diversity and prevalence. To illustrate the challenges of genotyping bacteria, we focus on the genusBartonella, vector-borne bacteria common in mammals. We highlight the value and limitations of commonly used techniques for genotyping bartonellae and make recommendations for researchers interested in studying the diversity of these bacteria in various samples. Our recommendations could be applicable to many bacterial taxa (with some modifications) and could lead to a more complete understanding of bacterial species diversity.

Human Lice in Paleoentomology and Paleomicrobiology

Lice are a classic example of cospeciation. Human lice confirm this cospeciation with lice specialized in hominids which differ from those of gorillas and chimpanzees. Head lice and body lice seem to belong to closely related species with different ecotypes and a different geographical distribution which may reflect population movements. Paleo-entomology allows us in some cases to trace the migrations of archaic human populations. The analysis of lice found on mummies in Egypt and South America has clarified a certain number of these migrations, also the study of lice and the diseases they transmit has shed a new light on the epidemics of the past.

Molecular Markers of Pesticide Resistance and Pathogens in Human Head Lice (Phthiraptera: Pediculidae) From Rural Georgia, USA

Although the head louse, Pediculus humanus capitis De Geer, and body louse, Pediculus humanus humanus L., both have a worldwide distribution, the occurrence of head louse pediculosis appears to be more prevalent in modern societies despite systematic use of various pediculicides. This study tested head lice collected in rural Georgia and body lice collected in Russia for the prevalence of a kdr-biomarker that is associated with permethrin resistance. This study also screened lice for the presence of DNA from Bartonella quintana and Acinetobacter species. The kdr-permethrin resistance biomarker for the T917I mutation was detected by RFLP and PCR in 99.9% of head lice tested from Georgia, whereas only 2.9% of body lice from Russia tested positive for this kdr biomarker. DNA of B. quintana was detected in 10.3% of head lice from Georgia, whereas 84.8% of body lice from Russia tested positive. Acinetobacter DNA was detected in 80.8% (95% CI, 68-89%) of head lice from Georgia and all body lice from Russia tested.

Human head lice and pubic lice reveal the presence of several Acinetobacter species in Algiers, Algeria

There are two majorspecies of medically important lice that parasitize humans: Phthirus pubis, found in pubic hair, and Pediculus humanus. Pediculus humanus consists of two eco types that live in specific niches on the human host: body lice (Pediculus humanus humanus), found on the human body and clothing, and head lice (Pediculus humanus capitis), found on the scalp. To date, only body lice are known to be vectors of human disease; however, it has recently been reported that the DNA of several bacterial agents has been detected in head lice, raising questions about their role in the transmission of pathogens. This issue caught our attention, in addition to the fact that the pathogenic bacteria associated with P. pubis and P. humanus capitis have never been investigated in Algeria. To investigate this,molecular techniques (real-time PCR) were used to screen for the presence of Acinetobacter spp., Bartonella spp., Borrelia spp. and Rickettsia prowazekii DNA from P. humanus capitis (64 lice) collected from schoolchildren,and P. pubis (4 lice),collected from one adultman living in Algiers. Positive samples for Acinetobacter spp.were identified by sequencing therpoBgene. Conventional PCR targeting the partial Cytb gene was used to determine the phylogenetic clade of the collected lice. Of the 64 samples collected, Acinetobacter spp. DNA was detected in 17/64 (27%) of head lice, identified as: A. baumannii (14%), A. johnsonii (11%) and A. variabilis (2%). Of the four P. pubissamples, 2(50%) were positive for A. johnsonii. The phylogenetic tree based on the Cytb gene revealed that P. humanus capitis were grouped into clades A and B. In this study, we report andidentify for the first time Acinetobacter spp.in Algerian P. pubis and P. humanus capitis. The detection of the genus Acinetobacter in lice should not be underestimated, especially in P. humanus capitis, which is distributed worldwide. However, additional epidemiological data are required to determine if human lice may act as an environmental reservoir and are actively involved in the propagation of these bacteria to humans.