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

Abstract

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.

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

“…For further studies, a more specific duplex system will be optimized, for better identification of African human lice, as well as to establish an optimal qPCR duplex for the discrimination of all human lice belonging to all existing haplogroups, including the recently described clade F. The phylogenetic study showed the existence of 8 haplotypes including 6 novels described for the first time in this study. The presence of clade E in both rural and urban communities in Guinean lice is not surprising, as it confirms the high prevalence of the "African endemic" clade E, as previously reported so far [18,26,28,29]. The most prevalent haplotype reported in our head lice is the E39 obtained with 68.1%, followed by the haplotype E48 with 8.5% of the total prevalence.…”

“…More recently, this clade has also been found in head lice collected from individuals in Gabon, belonging to haplotype E46 [29], already reported among lice collected in Mali [18]. These results suggest that the significant migratory exchange between Gabon and the Republic of the Congo can be the source for the clade E expansion [29]. In addition, among the 141 head lice cytb sequences analyzed, 4 lice with two different haplotypes, E39 and E70, were collected from the same 34-year-old woman.…”

“…However, a recent study showed for the first time the presence of clade E, more specifically the E62 haplotype in Central Africa, in Congo, suggesting that Congonians are in direct contact with West African populations or travelers arriving form West African countries [28]. More recently, this clade has also been found in head lice collected from individuals in Gabon, belonging to haplotype E46 [29], already reported among lice collected in Mali [18]. These results suggest that the significant migratory exchange between Gabon and the Republic of the Congo can be the source for the clade E expansion [29].…”

“…in only 14 head lice infesting 11 individuals. Findings from previous studies reported a worldwide spread of several Acinetobacter species, including A. baumannii, A. junii, A. ursingii, A. johnsonii, A. schindleri, A. lwoffii, A. nosocomialis, A. towneri, A. variabilis, A. radioresistens, A. calcoaceticus, A. soli, A. pittii and potential new species in head lice collected from different population categories, including elementary school children in Algeria [26,27], France [22], Thailand and Georgia-USA [19,24], of the Pygmy population in the Republic of Congo [21], Nigerian refugee children in Algeria [26] and, more recently, in head lice collected from healthy women in Gabon [29], and even in ancient Roman-era head lice remains [32]. The diversification of Acinetobacter species was reported from head lice belonging to the majority of the existing head lice-haplogroups A, D, C, E and B, and in different haplotypes of each haplogroup [11].…”

Head lice were also affected by COVID-19: a decrease on Pediculosis infestation during lockdown in Buenos Aires

“…This exclusive ectoparasite that feeds on blood and spends its entire life cycle on its host head has been associated with humans since the origin of humankind (Reed et al 2004 ). Combining both epidemiological and laboratory studies, head lice can transmit pathogens to their host under favorable epidemiological conditions, although its vectorial capacity is weaker in comparison to body lice ( Pediculus humanus humanus ) (Boumbanda-Koyo et al 2020 ). However, bacterial secondary infections may appear caused by the scratching of the head scalp due to the blood feeding and excretory behavior of these parasites.…”