Bartonella quintana in Head Lice from Sénégal

High mitochondrial gene diversity of Pediculus humanus capitis among children in northern Iran

BACKGROUND

The head louse, Pediculus humanus capitis, is an obligate ectoparasite and its infestation remains a major public health issue worldwide. Determining the genetic characteristics of the existing clades is essential to identify the population structure and to develop head lice-control programs. Hence, we aimed to investigate the genetic diversity of head lice among infested individuals in northern Iran.

METHODS

Adult head lice were collected from 100 infested individuals referring to the health centers throughout five geographical regions in Mazandaran Province, Iran. Partial fragments of the mitochondrial cytb gene were amplified by PCR, then consequently sequenced.

RESULTS

The results of the phylogenetic tree of collected head lice confirmed the existence of two clades, A and B, in the studied areas. Thirteen haplotypes were detected in the studied populations, of which 11 were novel haplotypes. Clade A was the dominant form and accounted for 75% of samples, while clade B included the rest. Haplotype and nucleotide diversity were 0.999 and 0.0411, respectively.

CONCLUSIONS

Clade A and B of Pediculus humanus capitis exist among the human populations of northern Iran. We observed high genotypic diversity of this head lice.

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.

Phylogenetic and network analysis of Pediculus humanus in Nigeria reveal the presences of clade E body lice and novel haplotypes

An investigation was conducted for the first time to determine the prevalence and genetic diversity of human lice, for the first time in Nigeria, using conventional PCR and sequencing methods. Three mitochondrial genes, cytochrome oxidase subunit 1 (cox1), cytochrome b (cytb), and 12S rRNA of Nigerian human lice, were amplified, sequenced, and analyzed. Overall, high prevalence (72.5%; 103/142) of lice infestation was recorded among the examined volunteers. Head lice infestation was more common 63 (61.2%) than body lice infestation 34 (33.0%). Co-infestation with both head and body lice was recorded in six humans (5.8%). The Nigerian human lice specimens were placed mostly into clade A with few in clade E, including body lice for the first time. Six, three, and eight haplotypes of Nigerian human lice were obtained for the cytb, cox1, and 12S rRNA genes, respectively. Additionally, one (E51), three (A31, A32, and E5), and six (A20, A21, A23, A24, A30, and E1) novel haplotypes were recorded for cox1, cytb, and 12S rRNA, respectively, from the Nigerian specimens which were corroborated by the ML phylogenetic trees and MJ network analyses. Genetic diversity indices indicate minimal variation in the parameters analyzed among the clades of the three genes. However, a statistically significant Snn test, negative Tajima's D test for clade A (cox1 and 12S rRNA genes), and negative Fu and Li's D test in clade A for cox1 gene indicate a geographical structure and the signature of population expansion of the Nigerian human lice. The findings from this study provide additional data on the human lice structure in Africa.

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.

Lice and lice-borne diseases in humans in Africa: a narrative review

Lice are host-specific insects. Human lice include Pediculus humanus humanus (body lice) which are known to be vectors of serious human bacterial infectious diseases including epidemic typhus, relapsing fever, trench fever and plague; Pediculus humanus capitis (head lice) that frequently affect children; and Pthirus pubis, commonly known as crab lice. In Africa, human infections transmitted by lice remained poorly known and therefore, underestimated, perhaps due to the lack of diagnostic tools and professional knowledge. In this paper we review current knowledge of the microorganisms identified in human lice in the continent of Africa, in order to alert health professionals to the importance of recognising the risk of lice-related diseases.

Human pediculosis, a global public health problem

Background

Human pediculosis is caused by hematophagous lice, which are transmitted between individuals via direct and/or indirect contact. Despite the public health importance of louse infestation, information concerning the global burden of pediculosis and the epidemiological landscape of louse-borne diseases is limited. The aim of this review was to summarize the biology, epidemiology, diagnosis, and control of lice infestation in humans. We also discussed the latest advances in molecular taxonomy and molecular genetics of lice.

Methods

We searched five electronic bibliographic databases (PubMed, ScienceDirect, CNKI, VIP Chinese Journal Database, and Wanfang Data) and followed a standard approach for conducting scoping reviews to identify studies on various aspects of human lice. Relevant information reported in the identified studies were collated, categorized, and summarized.

Results

A total of 282 studies were eligible for the final review. Human pediculosis remains a public health issue affecting millions of people worldwide. Emerging evidence suggests that head lice and body lice should be considered conspecific, with different genotypes and ecotypes. Phylogenetic analysis based on mitochondrial (mt) cytb gene sequences identified six distinct clades of lice worldwide. In addition to the direct effect on human health, lice can serve as vectors of disease-causing pathogens. The use of insecticides plays a crucial role in the treatment and prevention of louse infestation. Genome sequencing has advanced our knowledge of the genetic structure and evolutionary biology of human lice.

Conclusions

Human pediculosis is a public health problem affecting millions of people worldwide, particularly in developing countries. More progress can be made if emphasis is placed on the use of emerging omics technologies to elucidate the mechanisms that underpin the physiological, ecological, and evolutionary aspects of lice.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-022-00986-w.

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.

Detection of Potential Zoonotic Bartonella Species in African Giant Rats (Cricetomys gambianus) and Fleas from an Urban Area in Senegal

Bartonellae are bacteria associated with mammals and their ectoparasites. Rodents often host different species of Bartonella. The aim of this study was to investigate the presence of Bartonella spp. in African giant pouched rats (Cricetomys gambianus) and their ectoparasites in Dakar, Senegal. In 2012, 20 rats were caught, and their fleas were identified. DNA was extracted from 170 selected fleas and qPCR was carried out to detect Bartonella spp. Subsequently, a Bartonella culture was performed from the rat blood samples and the isolated strains (16S rRNA, rpoB, ftsZ and ITS3) were genotyped. A total of 1117 fleas were collected from 19 rats and identified as Xenopsylla cheopis, the tropical rat flea. Bartonella DNA was detected in 148 of 170 selected fleas (87.1%). In addition, Bartonella strains were isolated from the blood of 17 rats (85%). According to Bartonella gene-sequence-based criteria for species definition, the isolated strains were identified as B. massiliensis (four strains) and two potential new species related to the zoonotic B. elizabethae. In this paper, these potentially new species are provisionally called Candidatus Bartonella militaris (11 strains) and Candidatus Bartonella affinis (two strains) until their description has been completed. Cricetomys gambianus and its fleas could constitute a public health risk in Dakar due to the high prevalence of Bartonella infection reported.

Molecular Characterization and Genetic Diversity of Haplogroup E Human Lice in Guinea, West Africa

Pediculus humanus capitis, the head louse, is an obligate blood-sucking ectoparasite that occurs in six divergent mitochondrial clades (A, D, B, F, C and E). Several studies reported the presence of different pathogenic agents in head lice specimens collected worldwide. These findings suggest that head louse could be a dangerous vector and a serious public health problem. Herein, we aimed to study the mitochondrial genetic diversity, the PHUM540560 gene polymorphisms profile of head lice collected in Guinea, as well as to screen for their associated pathogens. In 2018, a total of 155 head lice were collected from 49 individuals at the Medicals Centers of rural (Maférinyah village) and urban (Kindia city) areas, in Guinea. Specimens were subjected to a genetic analysis and pathogens screening using molecular tools. Results showed that all head lice belonged to eight haplotypes in the E haplogroup, with six newly identified for the first time. The study of the PHUM540560 gene polymorphisms of our clade E-head lice revealed that 82.5% exhibited the same polymorphism profile as the previously reported clade A-body lice. Screening for targeted pathogens revealed the presence of Acinetobacter spp., while sequencing highlighted the presence of several species, including Acinetobacter baumannii, Acinetobacter nosocomialis, Acinetobacter variabilis, Acinetobacter towneri and for the first time Acinetobacter haemolyticus. Our study is the first to report the existence of the Guinean haplogroup E, the PHUM540560 gene polymorphism profile as well as the presence of Acinetobacter species in head lice collected from Guinea.

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.

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.

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.

Molecular Survey of Rickettsia spp., Anaplasma spp., Ehrlichia spp., Bartonella spp., and Borrelia spp. in Fleas and Lice in Ethiopia

Bacterial arthropod-borne pathogens can often cause fever in Africa, but rural laboratories in these settings are usually too basic to provide a precise picture of their epidemiological impact. Our aim was to determine the prevalence of bacterial pathogens in fleas and lice in a rural area of southeast Ethiopia. Between July and November 2013, we extracted DNA from 91 fleas (Ctenocephalides felis [n = 50; 54.9%], Pulex irritans [n = 37; 40.1%], and C. canis [n = 4; 4.4%] and 30 lice (Pediculus humanus capitis [n = 16; 53.3%] and Pediculus humanus humanus [n = 14; 46.7%]), using two quantitative PCR (qPCR) analyses to look for bacteria from the genera: Anaplasma, Bartonella, Borrelia, Coxiella, Ehrlichia, Francisella, and Rickettsia. Of the 91 fleas analyzed, pathogens were present in 79 (86.8%), including Rickettsia felis (n = 41; 45%), Anaplasma platys (n = 40; 44.0%), Rickettsia monacensis (n = 2; 2.2%), Ehrlichia muris-like agent (n = 1; 1.1%), and Bartonella clarridgeiae (n = 1; 1.1%). P. irritans was the flea species most frequently infected with A. platys (67.7%), followed by C. felis (30.7%) (p < 0.001). Of the 30 lice identified, pathogens were present in 7 (23.3%): Bartonella quintana (n = 4; 16.7%), E. muris (n = 2, 6.7%), and Borrelia recurrentis (n = 1, 3.3%). Thus, in this rural area of Africa, fleas and lice can transmit parasitic pathogens to humans, causing febrile symptoms.

Human Exposure to Novel Bartonella Species from Contact with Fruit Bats

Twice a year in southwestern Nigeria, during a traditional bat festival, community participants enter designated caves to capture bats, which are then consumed for food or traded. We investigated the presence of Bartonella species in Egyptian fruit bats (Rousettus aegyptiacus) and bat flies (Eucampsipoda africana) from these caves and assessed whether Bartonella infections had occurred in persons from the surrounding communities. Our results indicate that these bats and flies harbor Bartonella strains, which multilocus sequence typing indicated probably represent a novel Bartonella species, proposed as Bartonella rousetti. In serum from 8 of 204 persons, we detected antibodies to B. rousetti without cross-reactivity to other Bartonella species. This work suggests that bat-associated Bartonella strains might be capable of infecting humans.

Genetic diversity of human head lice and molecular detection of associated bacterial pathogens in Democratic Republic of Congo

BACKGROUND

Head louse, Pediculus humanus capitis, is an obligatory blood-sucking ectoparasite, distributed worldwide. Phylogenetically, it occurs in five divergent mitochondrial clades (A-E); each exhibiting a particular geographical distribution. Recent studies suggest that, as in the case of body louse, head louse could be a disease vector. We aimed to study the genetic diversity of head lice collected in the Democratic Republic of the Congo (DR Congo) and to screen for louse-borne pathogens in these lice.

METHODS

A total of 181 head lice were collected from 27 individuals at the Monkole Hospital Center located in Kinshasa. All head lice were genotyped and screened for the presence of louse-borne bacteria using molecular methods. We searched for Bartonella quintana, Borrelia recurrentis, Rickettsia prowazekii, Anaplasma spp., Yersinia pestis, Coxiella burnetii and Acinetobacter spp.

RESULTS

Among these head lice, 67.4% (122/181) belonged to clade A and 24.3% (44/181) belonged to clade D. Additionally, for the first time in this area, we found clade E in 8.3% (15/181) of tested lice, from two infested individuals. Dual infestation with clades A and D was observed for 44.4% individuals. Thirty-three of the 181 head lice were infected only by different bacterial species of the genus Acinetobacter. Overall, 16 out of 27 individuals were infested (59.3%). Six Acinetobacter species were detected including Acinetobacter baumannii (8.3%), Acinetobacter johnsonii (1.7%), Acinetobacter soli (1.7%), Acinetobacter pittii (1.7%), Acinetobacter guillouiae (1.1%), as well as a new potential species named "Candidatus Acinetobacter pediculi".

CONCLUSIONS

To our knowledge, this study reports for the first time, the presence of clade E head lice in DR Congo. This study is also the first to report the presence of Acinetobacter species DNAs in human head lice in DR Congo.

Detection of bacterial pathogens in clade E head lice collected from Niger's refugees in Algeria

Background

Head lice, Pediculus humanus capitis, are obligate blood-sucking parasites. Phylogenetically, they occur in five divergent mitochondrial clades (A, D, B, C and E), each having a particular geographical distribution. Recent studies have revealed that head lice, as is the case of body lice, can act as a vector for louse-borne diseases. Here, we aimed to study the genetic diversity of head lice collected from Niger’s refugees (migrant population) arriving in Algeria, northern Africa, and to look for louse-borne pathogens. Comparative head lice samples collected from indigenous population of schoolchildren (non-immigrant) were also analyzed to frame the study.

Results

In this study, 37 head lice samples were collected from 31 Nigerien refugees, as well as 45 head lice from 27 schoolchildren. The collection was established in three localities of eastern Algiers, north Algeria. Quantitative real-time PCR screening of pathogens bacteria and the genetic characterisation of the head lice satut were performed. Through amplification and sequencing of the cytb gene, results showed that all head lice of Nigerien refugees 37/82 (45.12%) belonged to clade E with the presence of four new haplotypes, while, of the 45 head lice of schoolchildren, 34/82 lice (41.46%) belonged to clade A and 11/82 (13.41%) belonged to clade B. Our study is the first to report the existence of clade E haplogroup in Nigerien head lice. DNA of Coxiella burnetii was detected in 3/37 (8.10%) of the head lice collected from 3 of the 31 (9.67%) migrant population. We also revealed the presence of Acinetobacter DNA in 20/37 (54.05%) of head lice collected from 25/31 (80.64%) of the Nigerien refugees, and in 25/45 (55.55%) head lice collected from 15/27 (55.55%) schoolchildren. All positive Nigerien-head lice for Acinetobacter spp. were identified as A. baumannii, while positive schoolchildren-head lice were identified as A. johnsonii 15/25 (60%), A. variabilis 8/25 (32%) and A. baumannii 2/25 (8%).

Conclusions

Based on these findings from head lice collected on migrant and non-migrant population, our results show, for the first time, that head lice from Niger belong to haplogroup E, and confirm that the clade E had a west African distribution. We also detected, for the first time, the presence of C. burnetii and A. baumannii in these Nigerien head lice. Nevertheless, further studies are needed to determine whether the head lice can transmit these pathogenic bacteria from one person to another.

Medical Entomology: A Reemerging Field of Research to Better Understand Vector-Borne Infectious Diseases

In the last decade, the Chikungunya and Zika virus outbreaks have turned public attention to the possibility of the expansion of vector-borne infectious diseases worldwide. Medical entomology is focused on the study of arthropods involved in human health. We review here some of the research approaches taken by the medical entomology team of the University Hospital Institute (UHI) Méditerranée Infection of Marseille, France, with the support of recent or representative studies. We propose our approaches to technical innovations in arthropod identification and the detection of microorganisms in arthropods, the use of arthropods as epidemiological or diagnostic tools, entomological investigations around clinical cases or within specific populations, and how we have developed experimental models to decipher the interactions between arthropods, microorganisms, and humans.

Body lice of homeless people reveal the presence of several emerging bacterial pathogens in northern Algeria

BACKGROUND

Human lice, Pediculus humanus, are obligate blood-sucking parasites. Body lice, Pediculus h. humanus, occur in two divergent mitochondrial clades (A and D) each exhibiting a particular geographic distribution. Currently, the body louse is recognized as the only vector for louse-borne diseases. In this study, we aimed to study the genetic diversity of body lice collected from homeless populations in three localities of northern Algeria, and to investigate louse-borne pathogens in these lice.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, 524 body lice specimens were collected from 44 homeless people in three localities: Algiers, Tizi Ouzou and Boumerdès located in northern Algeria. Duplex clade specific real-time PCRs (qPCR) and Cytochrome b (cytb) mitochondrial DNA (mtDNA) analysis were performed in order to identify the mitochondrial clade. Screening of louse-borne pathogens bacteria was based on targeting specific genes for each pathogen using qPCR supplemented by sequencing. All body lice belong to clade A. Through amplification and sequencing of the cytb gene we confirmed the presence of three haplotypes: A5, A9 and A63, which is novel. The molecular investigation of the 524 body lice samples revealed the presence of four human pathogens: Bartonella quintana (13.35%), Coxiella burnetii (10.52%), Anaplasma phagocytophilum (0.76%) and Acinetobacter species (A. baumannii, A. johnsonii, A. berezeniae, A. nosocomialis and A. variabilis, in total 46.94%).

CONCLUSIONS/SIGNIFICANCE

To the best of our knowledge, our study is the first to show the genetic diversity and presence of several emerging pathogenic bacteria in homeless' body lice from Algeria. We also report for the first time, the presence of several species of Acinetobacter in human body lice. Our results highlight the fact that body lice may be suspected as being a much broader vector of several pathogenic agents than previously thought. Nevertheless, other studies are needed to encourage epidemiological investigations and surveys of louse-associated infections.

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.

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.

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.

Bacterial arthropod-borne diseases in West Africa

Arthropods such as ticks, lice, fleas and mites are excellent vectors for many pathogenic agents including bacteria, protozoa and viruses to animals. Moreover, many of these pathogens can also be accidentally transmitted to humans throughout the world. Bacterial vector-borne diseases seem to be numerous and very important in human pathology, however, they are often ignored and are not well known. Yet they are in a phase of geographic expansion and play an important role in the etiology of febrile episodes in regions of Africa. Since the introduction of molecular techniques, the presence of these pathogens has been confirmed in various samples from arthropods and animals, and more rarely from human samples in West Africa. In this review, the aim is to summarize the latest information about vector-borne bacteria, focusing on West Africa from 2000 until today in order to better understand the epidemiological risks associated with these arthropods. This will allow health and veterinary authorities to develop a strategy for surveillance of arthropods and bacterial disease in order to protect people and animals.

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.

Flammability testing of 22 conventional European pediculicides

Lice have been parasitizing humans for at least 10,000 years. Since then, humans have tried to rid themselves of these unpleasant and potentially disease-carrying insects. Despite various plant extracts and chemical compounds being used to combat recurring infestations to this date, several lice populations have developed resistance to some of the abundantly used compounds. This resulted in the development of anti-louse products that physically kill the different lice stages. Today, a widely used group of delousing agents are dimethicones (polydimethylsiloxane PDMS) which function by suffocating the lice. However, many dimethicones and related products are highly flammable which makes them potentially dangerous for treatment. In the present study, we tested the flammability of 22 delousing agents in order to shed some light onto this currently unresolved problem in the product design of pediculicides. Thirteen products were easily ignitable, some even by distant contact with a sparkler.

Bartonella dromedarii sp. nov. isolated from domesticated camels (Camelus dromedarius) in Israel

Bartonella spp. are fastidious, Gram-negative bacilli that cause a wide spectrum of diseases in humans. Most Bartonella spp. have adapted to a specific host, generally a domestic or wild mammal. Dromedary camels (Camelus dromedarius) have become a focus of growing public-health interest because they have been identified as a reservoir host for the Middle East respiratory syndrome coronavirus. Nevertheless, data on camel zoonoses are limited. We aimed to study the occurrence of Bartonella bacteremia among dromedaries in Israel. Nine of 51 (17.6%) camels were found to be bacteremic with Bartonella spp.; bacteremia levels ranged from five to >1000 colony-forming units/mL. Phylogenetic reconstruction based on the concatenated sequences of gltA and rpoB genes demonstrated that the dromedary Bartonella isolates are closely related to other ruminant-derived Bartonella spp., with B. bovis being the nearest relative. Using electron microscopy, the novel isolates were shown to be flagellated, whereas B. bovis is nonflagellated. Sequence comparisons analysis of the housekeeping genes ftsZ, ribC, and groEL showed the highest homology to B. chomelii, B. capreoli, and B. birtlesii, respectively. Sequence analysis of the gltA and rpoB revealed ∼96% identity to B. bovis, a previously suggested cutoff value for sequence-based differentiation of Bartonella spp., suggesting that this approach does not have sufficient discriminatory power for differentiating ruminant-related Bartonella spp. A comprehensive multilocus sequence typing (MLST) analysis based on nine genetic loci (gltA, rpoB, ftsZ, internal transcribed spacer (ITS), 16S rRNA, ribC, groEL, nuoG, and SsrA) identified seven sequence types of the new dromedary isolates. This is the first description of a Bartonella sp. from camelids. On the basis of a distinct reservoir and ecological niche, sequence analyses, and expression of flagella, we designate these isolates as a novel Bartonella sp. named Bartonella dromedarii sp. nov. Further studies are required to explore its zoonotic potential.

Bartonella bovis and Candidatus Bartonella davousti in cattle from Senegal

In Senegal, domestic ruminants play a vital role in the economy and agriculture and as a food source for people. Bartonellosis in animals is a neglected disease in the tropical regions, and little information is available about the occurrence of this disease in African ruminants. Human bartonellosis due to Bartonella quintana has been previously reported in Senegal. In this study, 199 domestic ruminants, including 104 cattle, 43 sheep, and 52 goats were sampled in villages from the Senegalese regions of Sine Saloum and Casamance. We isolated 29 Bartonella strains, all exclusively from cattle. Molecular and genetic characterization of isolated strains identified 27 strains as Bartonella bovis and two strains as potentially new species. The strains described here represent the first Bartonella strains isolated from domestic ruminants in Senegal and the first putative new Bartonella sp. isolated from cattle in Africa.

Management and Treatment of Human Lice

Of the three lice (head, body, and pubic louse) that infest humans, the body louse is the species involved in epidemics of louse-borne typhus, trench fever, and relapsing fever, but all the three cause pediculosis. Their infestations occur today in many countries despite great efforts to maintain high standards of public health. In this review, literature searches were performed through PubMed, Medline, Google Scholar, and EBSCOhost, with key search words of "Pediculus humanus", "lice infestation", "pediculosis", and "treatment"; and controlled clinical trials were viewed with great interest. Removing lice by hand or with a lice comb, heating infested clothing, and shaving the scalp were some of the oldest methods of controlling human lice. Despite the introduction of other resources including cresol, naphthalene, sulfur, mercury, vinegar, petroleum, and insecticides, the numbers of lice infestation cases and resistance have increased. To date, viable alternative treatments to replace insecticides have been developed experimentally in vitro. Today, the development of new treatment strategies such as symbiotic treatment and synergistic treatment (antibiotics + ivermectin) in vitro has proved effective and is promising. Here, we present an overview on managing and treating human lice and highlight new strategies to more effectively fight pediculosis and prevent resistance.

High diversity and rapid diversification in the head louse, Pediculus humanus (Pediculidae: Phthiraptera)

The study analyzes sequence variation of two mitochondrial genes (COI, cytb) in Pediculus humanus from three countries (Egypt, Pakistan, South Africa) that have received little prior attention, and integrates these results with prior data. Analysis indicates a maximum K2P distance of 10.3% among 960 COI sequences and 13.8% among 479 cytb sequences. Three analytical methods (BIN, PTP, ABGD) reveal five concordant OTUs for COI and cytb. Neighbor-Joining analysis of the COI sequences confirm five clusters; three corresponding to previously recognized mitochondrial clades A, B, C and two new clades, "D" and "E", showing 2.3% and 2.8% divergence from their nearest neighbors (NN). Cytb data corroborate five clusters showing that clades "D" and "E" are both 4.6% divergent from their respective NN clades. Phylogenetic analysis supports the monophyly of all clusters recovered by NJ analysis. Divergence time estimates suggest that the earliest split of P. humanus clades occurred slightly more than one million years ago (MYa) and the latest about 0.3 MYa. Sequence divergences in COI and cytb among the five clades of P. humanus are 10X those in their human host, a difference that likely reflects both rate acceleration and the acquisition of lice clades from several archaic hominid lineages.

Relapsing Fever Borreliae: A Global Review

Relapsing fever borreliae were notorious and feared infectious agents that earned their place in history through their devastating impact as causes of both epidemic and endemic infection. They are now considered more as an oddity, and their burden of infection is largely overshadowed by other infections such as malaria, which presents in a similar clinical way. Despite this, they remain the most common bacterial infection in some developing countries. Transmitted by soft ticks or lice, these fascinating spirochetes have evolved a myriad of mechanisms to survive within their diverse environments.

Evidence that clade A and clade B head lice live in sympatry and recombine in Algeria

Pediculus humanus L. (Psocodea: Pediculidae) can be characterized into three deeply divergent lineages (clades) based on mitochondrial DNA. Clade A consists of both head lice and clothing lice and is distributed worldwide. Clade B consists of head lice only and is mainly found in North and Central America, and in western Europe and Australia. Clade C, which consists only of head lice, is found in Ethiopia, Nepal and Senegal. Twenty-six head lice collected from pupils at different elementary schools in two localities in Algiers (Algeria) were analysed using molecular methods for genotyping lice (cytochrome b and the multi-spacer typing (MST) method. For the first time, we found clade B head lice in Africa living in sympatry with clade A head lice. The phylogenetic analysis of the concatenated sequences of these populations of head lice showed that clade A and clade B head lice had recombined, suggesting that interbreeding occurs when lice live in sympatry.

Molecular survey of the head louse Pediculus humanus capitis in Thailand and its potential role for transmitting Acinetobacter spp

BACKGROUND

Head louse infestation, which is caused by Pediculus humanus capitis, occurs throughout the world. With the advent of molecular techniques, head lice have been classified into three clades. Recent reports have demonstrated that pathogenic organisms could be found in head lice. Head lice and their pathogenic bacteria in Thailand have never been investigated. In this study, we determined the genetic diversity of head lice collected from various areas of Thailand and demonstrated the presence of Acinetobacter spp. in head lice.

METHODS

Total DNA was extracted from 275 head louse samples that were collected from several geographic regions of Thailand. PCR was used to amplify the head louse COI gene and for detection of Bartonella spp. and Acinetobacter spp. The amplified PCR amplicons were cloned and sequenced. The DNA sequences were analyzed via the neighbor-joining method using Kimura's 2-parameter model.

RESULTS

The phylogenetic tree based on the COI gene revealed that head lice in Thailand are clearly classified into two clades (A and C). Bartonella spp. was not detected in all the samples, whereas Acinetobacter spp. was detected in 10 samples (3.62%), which consisted of A. baumannii (1.45%), A. radioresistens (1.45%), and A. schindleri (0.72%). The relationship of Acinetobacter spp. and the head lice clades showed that Acinetobacter spp. was found in clade A and C.

CONCLUSIONS

Head lice in Thailand are classified into clade A and B based on the COI gene sequences. Pathogenic Acinetobacter spp. was detected in both clades. The data obtained from the study might assist in the development of effective strategies for head lice control in the future. Detection of pathogenic bacteria in head lice could raise awareness of head lice as a source of nosocomial bacterial infections.

Detection of Bartonella quintana in African body and head lice

Currently, the body louse is the only recognized vector of Bartonella quintana, an organism that causes trench fever. In this work, we investigated the prevalence of this bacterium in human lice in different African countries. We tested 616 head lice and 424 body lice from nine African countries using real-time polymerase chain reaction targeting intergenic spacer region 2 and specific B. quintana genes. Overall, B. quintana DNA was found in 54% and 2% of body and head lice, respectively. Our results also show that there are more body lice positive for B. quintana in poor countries, which was determined by the gross domestic product, than in wealthy areas (228/403 versus 0/21, P < 0.001). A similar finding was obtained for head lice (8/226 versus 2/390, P = 0.007). Our findings suggest that head lice in Africa may be infected by B. quintana when patients live in poor economic conditions and are also exposed to body lice.

Prevalence of Bartonella quintana in patients with fever and head lice from rural areas of Sine-Saloum, Senegal

Trench fever is poorly known by the staff of health facilities that manage febrile patients in Senegal. Bartonella quintana DNA was identified in 5 of 274 (2%) febrile patients from two rural dispensaries and 2 of 71 (3%) head lice specimens collected from the same villages.

The origin and distribution of human lice in the world

Two genera of lice parasitize humans: Pthirus and Pediculus. The latter is of significant public health importance and comprises two ecotypes: the body louse and the head louse. These ecotypes are morphologically and genetically notably similar; the body louse is responsible for three infectious diseases: Louse-borne epidemic typhus, relapsing fever, and trench fever. Mitochondrial DNA studies have shown that there are three obviously divergent clades of head lice (A, B and C), and only one clade of body lice is shared with head lice (clade A). Each clade has a unique geographic distribution. Lice have been parasitizing humans for millions of years and likely dispersed throughout the World with the human migrations out of Africa, so they can be good markers for studying human evolution. Here, we present an overview of the origin of human lice and their role in vector pathogenic bacteria that caused epidemics, and we review the association between lice clades and human migrations.

Identification of Bartonellae in the soft tick species Ornithodoros sonrai in Senegal

Ticks, belonging to the soft ticks species Ornithodorus sonrai, have been collected from six sites in Senegal and were tested for the presence of Bartonella spp. Initial screening by PCR revealed the presence of these bacteria in ticks from two villages, Soulkhou Thissé (5/8, 62.5%) and Maka Gouye (1/24, 4.2%). Three bacterial strains were isolated from live ticks, and the genetic characterization of these strains suggests that they belong to two previously unknown species. The pathogenicity of these two new species of Bartonella is not yet known. The new isolates described here are the first strains of Bartonella spp. from soft ticks and the first isolates from any arthropod species in Africa.

Evidence of sympatry of clade a and clade B head lice in a pre-Columbian Chilean mummy from Camarones

Three different lineages of head lice are known to parasitize humans. Clade A, which is currently worldwide in distribution, was previously demonstrated to be present in the Americas before the time of Columbus. The two other types of head lice are geographically restricted to America and Australia for clade B and to Africa and Asia for clade C. In this study, we tested two operculated nits from a 4,000-year-old Chilean mummy of Camarones for the presence of the partial Cytb mitochondrial gene (270 bp). Our finding shows that clade B head lice were present in America before the arrival of the European colonists.

Borrelia recurrentis in head lice, Ethiopia

Since the 1800s, the only known vector of Borrelia recurrentis has been the body louse. In 2011, we found B. recurrentis DNA in 23% of head lice from patients with louse-borne relapsing fever in Ethiopia. Whether head lice can transmit these bacteria from one person to another remains to be determined.

Genetic recombination events between sympatric Clade A and Clade C lice in Africa

Human head and body lice have been classified into three phylogenetic clades (Clades A, B, and C) based on mitochondrial DNA. Based on nuclear markers (the 18S rRNA gene and the PM2 spacer), two genotypes of Clade A head and body lice, including one that is specifically African (Clade A2), have been described. In this study, we sequenced the PM2 spacer of Clade C head lice from Ethiopia and compared these sequences with sequences from previous works. Trees were drawn, and an analysis of genetic diversity based on the cytochrome b gene and the PM2 spacer was performed for African and non-African lice. In the tree drawn based on the PM2 spacer, the African and non-African lice formed separate clusters. However, Clade C lice from Ethiopia were placed within the African Clade A subcluster (Clade A2). This result suggests that recombination events have occurred between Clade A2 lice and Clade C lice, reflecting the sympatric nature of African lice. Finally, the PM2 spacer and cytochrome b gene sequences of human lice revealed a higher level of genetic diversity in Africa than in other regions.

Amazonian head lice-specific genotypes are putatively pre-Columbian

Head and body lice are strict obligate human ectoparasites with three mitochondrial phylotypes (A, B, and C). Using molecular methods for genotyping lice (Cytochrome b and multi-spacer typing), and comparing our results with all the sequences of human lice that were genotyped previously, we assessed the presence of a specific American genotype that most likely predates the Columbian era in head lice collected from Amazonia.

Distinguishing body lice from head lice by multiplex real-time PCR analysis of the Phum_PHUM540560 gene

BACKGROUND

Body louse or head louse? Once removed from their environment, body and head lice are indistinguishable. Neither the morphological criteria used since the mid-18th century nor the various genetic studies conducted since the advent of molecular biology tools have allowed body lice and head lice to be differentiated. In this work, using a portion of the Phum_PHUM540560 gene from the body louse, we aimed to develop a multiplex real-time polymerase chain reaction (PCR) assay to differentiate between body and head lice in a single reaction.

MATERIALS AND METHODS

A total of 142 human lice were collected from mono-infested hosts from 13 countries on five continents. We first identified the louse clade using a cytochrome b (CYTB) PCR sequence alignment. We then aligned a fragment of the Phum_PHUM540560 gene amplified from head and body lice to design-specific TaqMan(©) FAM- and VIC-labeled probes.

RESULTS

All the analyzed lice were Clade A lice. A total of 22 polymorphisms between the body and head lice were characterized. The multiplex real-time PCR analysis enabled the body and head lice to be distinguished in two hours. This method is simple, with 100% specificity and sensitivity.

CONCLUSIONS

We confirmed that the Phum_PHUM540560 gene is a useful genetic marker for the study of lice.

Point-of-care laboratory of pathogen diagnosis in rural Senegal

BACKGROUND

In tropical Africa, where the spectrum of the bacterial pathogens that cause fevers is poorly understood and molecular-based diagnostic laboratories are rare, the time lag between test results and patient care is a critical point for treatment of disease.

METHODOLOGY/PRINCIPAL FINDINGS

We implemented POC laboratory in rural Senegal to resolve the time lag between test results and patient care. During the first year of the study (February 2011 to January 2012), 440 blood specimens from febrile patients were collected in Dielmo and Ndiop villages. All samples were screened for malaria, dengue fever, Borrelia spp., Coxiella burnetii, Tropheryma whipplei, Rickettsia conorii, R. africae, R. felis, and Bartonella spp.

CONCLUSIONS/SIGNIFICANCE

We identified DNA from at least one pathogenic bacterium in 80/440 (18.2%) of the samples from febrile patients. B. crocidurae was identified in 35 cases (9.5%), and R. felis DNA was found in 30 cases (6.8%). The DNA of Bartonella spp. was identified in 23/440 cases (4.3%), and DNA of C. burnetii was identified in 2 cases (0.5%). T. whipplei (0.2%) was diagnosed in one patient. No DNA of R. africae or R. conorii was identified. Among the 7 patients co-infected by two different bacteria, we found R. felis and B. crocidurae in 4 cases, B. crocidurae and Bartonella spp. in 2 cases, and B. crocidurae and C. burnetii in 1 case. Malaria was diagnosed in 54 cases. In total, at least one pathogen (bacterium or protozoa) was identified in 127/440 (28.9%) of studied samples. Here, the authors report the proof of concept of POC in rural tropical Africa. Discovering that 18.2% of acute infections can be successfully treated with doxycycline should change the treatment strategy for acute fevers in West Africa.