Amina Boutellis

Bartonella quintana in Head Lice from Sénégal

Head and body lice are strict, obligate human ectoparasites with three mitochondrial clades (A, B, and C). Body lice have been implicated as vectors of human diseases, and as the principal vectors of epidemic typhus, relapsing fever, and Bartonella quintata-associated diseases (trench fever, bacillary angiomatosis, endocarditis, chronic bacteremia, and chronic lymphadenopathy). Using molecular methods (real-time and traditional PCR), we assessed the presence of Bartonella quintana DNA in black head lice collected from three locations in Sénégal. DNA from B. quintana was identified in 19 lice (6.93%) collected from 7 patients (7%) in Dakar. B. quintana-positive lice collected from three subjects were identified as clades C and A.

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.

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.

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.

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.

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.

Bartonella quintana in Body Lice from Scalp Hair of Homeless Persons, France

To the Editor: Bartonella quintana is a body louse–borne human pathogen that can cause trench fever, bacillary angiomatosis, endocarditis, chronic bacteremia, and chronic lymphadenopathy (1). Recently, B. quintana DNA was detected in lice collected from the heads of poor and homeless persons from the United States, Nepal, Senegal, Ethiopia, and the Democratic Republic of the Congo and in nits in France (2,3). The head louse, Pediculus humanus capitis, and the body louse, Pediculus humanus humanus, are obligatory ectoparasites that feed exclusively on human blood (4). Outside of their habitats, the 2 ecotypes are morphologically indistinguishable (1). Sequence variation in the PHUM540560 gene discriminates between head and body lice by determining the genotype of the lice (5). While surveying for trench fever among homeless persons in shelters in Marseille, France during October 2012–March 2013, we investigated the presence of B. quintana DNA in nits, larvae, and adult lice collected from mono-infested and dually infested persons and determined the genotypes of the specimens. n nThe persons included in this study received long-lasting insecticide-treated underwear; lice were collected by removing them from clothing, including underwear, pants, and shirts. Because body lice reside in the clothing of infested persons except when feeding, they are sometimes called clothing lice. n nA total of 989 specimens were tested, including 149 (83 from clothing and 66 from hair) first–instar larvae hatched in the laboratory from eggs collected from 7 dually infested persons, and 840 adult body lice collected from the clothing of 80 mono-infested patients. We included DNA isolated from 3 nits collected from the hair of a mono-infested person who had previously been confirmed as positive for B. quintana (6) (Table). n n n nTable n nDistribution of Bartonella quintana DNA in nits, larvae, and adult body lice collected from hair and clothing of homeless persons in shelters, Marseille, France, October 2012– March 2013* n n n nTotal DNA was extracted by using an EZ1 automated extractor (QIAGEN, Courtaboeuf, France) and subjected twice to real-time PCR specific for B. quintana. The first PCR targeted the 16S-23S intergenic spacer region. Positive samples were confirmed by using a second real-time PCR targeting the yopP gene (6). Samples that tested positive for B. quintana DNA were analyzed by multiplex real-time PCR that targeted the PHUM540560 gene (5). We used head and body lice that had known genotypes positive controls. Negative controls were included in each assay. n nOf the hatched larvae, 5 (6%) of the 83 recovered from clothing and 7 (11%) of 66 from the hair (Table) of 4 of the 7 dually infested persons were positive for B. quintana DNA (Technical Appendix). Of the 840 adult body lice, 174 (21%) collected from 42 (53%) of 80 of the mono-infested persons contained B. quintana DNA (Table, Technical Appendix). The multiplex real-time PCR that targeted the PHUM540560 gene clearly identified all nits, larvae, and adult lice as belonging to the body lice lineage. Negative controls remained negative in all PCR-based experiments. n nFor 2 decades, B. quintana DNA has been regularly detected in lice collected from the heads of persons living in poverty, but it had not been detected in head lice that infest schoolchildren (7,8). All of the lice collected during this study that tested positive for B. quintana from homeless persons were body lice, including some that were recovered from hair. This observation supports our assertion that body lice are not confined to the body. The 3 eggs that were removed from the hair of a mono-infested homeless person whose samples tested positive for B. quintana were also body lice. During the clinical examination, no adult head lice or adult body lice were found on that person, confirming that the patient had been heavily infested with body lice in the past, not head lice. The nits were most likely laid by body lice that migrated toward the patient’s head. When a member of this research team (DR) collected the eggs from the hair shaft, they were found ≈3–3.5 cm from the hair follicle. Because hair grows ≈1.25 cm per month, the louse infestation occurred ≈3 months before egg collection (6). n nHomeless persons that we have monitored for many years are often heavily infested by body lice but are also occasionally infested with head lice. Before genetic tools that differentiate the head and body louse lineages were available (5), it was speculated that body lice may have originated from head lice (9). From our study, it is clear that under conditions of massive infestation, body lice can migrate and colonize hair; the opposite may also be true. However, there is no evidence that body lice are capable of causing an outbreak of lice living on the head, as happens among schoolchildren that have been found to be infested only by head lice. This suggests that body lice cannot thrive in the environment of head lice, which infest millions of children worldwide (10), further suggesting that outbreaks of trench fever are most likely not linked to head lice in industrialized countries. In conclusion, by analyzing lice harvested from the heads and clothing of homeless persons, we have shown that the 2 ecotypes belong to the same body lice population. n nTechnical Appendix: nDetailed distribution of B. quintana DNA among lice from mono-infested and dually infested homeless persons, France n nClick here to view.(33K, pdf)

Genetic Recombination Events between Sympatric Clade A and Clade C Lice in Africa

ABSTRACT n 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.

Host switching of human lice to new world monkeys in South America

The coevolution between a host and its obligate parasite is exemplified in the sucking lice that infest primates. In the context of close lice-host partnerships and cospeciation, Pediculus mjobergi, the louse of New World primates, has long been puzzling because its morphology resembles that of human lice. To investigate the possibility that P. mjobergi was transmitted to monkeys from the first humans who set foot on the American continent thousands of years ago, we obtained and compared P. mjobergi lice collected from howler monkeys from Argentina to human lice gathered from a remote and isolated village in Amazonia that has escaped globalization. Morphological examinations were first conducted and verified the similarity between the monkey and human lice. The molecular characterization of several nuclear and mitochondrial genetic markers in the two types of lice revealed that one of the P. mjobergi specimens had a unique haplotype that clustered with the haplotypes of Amazonian head lice that are prevalent in tropical regions in the Americas, a natural habitat of New World monkeys. Because this phylogenetic group forms a separate branch within the clade of lice from humans that were of American origin, this finding indicates that human lice have transferred to New World monkeys.