Head Lice of Pygmies Reveal the Presence of Relapsing Fever Borreliae in the Republic of Congo

Abstract

BackgroundHead lice, Pediculus humanus capitis, occur in four divergent mitochondrial clades (A, B, C and D), each having particular geographical distributions. Recent studies suggest that head lice, as is the case of body lice, can act as a vector for louse-borne diseases. Therefore, understanding the genetic diversity of lice worldwide is of critical importance to our understanding of the risk of louse-borne diseases.Methodology/Principal FindingsHere, we report the results of the first molecular screening of pygmies’ head lice in the Republic of Congo for seven pathogens and an analysis of lice mitochondrial clades. We developed two duplex clade-specific real-time PCRs and identified three major mitochondrial clades: A, C, and D indicating high diversity among the head lice studied. We identified the presence of a dangerous human pathogen, Borrelia recurrentis, the causative agent of relapsing fever, in ten clade A head lice, which was not reported in the Republic of Congo, and B. theileri in one head louse. The results also show widespread infection among head lice with several species of Acinetobacter. A. junii was the most prevalent, followed by A. ursingii, A. baumannii, A. johnsonii, A. schindleri, A. lwoffii, A. nosocomialis and A. towneri.Conclusions/SignificanceOur study is the first to show the presence of B. recurrentis in African pygmies’ head lice in the Republic of Congo. This study is also the first to report the presence of DNAs of B. theileri and several species of Acinetobacter in human head lice. Further studies are needed to determine whether the head lice can transmit these pathogenic bacteria from person to another.

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

“…Borrelia recurrentis was detected in clade C head lice from patients suffering with louse-borne relapsing fever living in poor regions from Ethiopia, and more recently in head lice clade A from hunter-gatherer pygmy individuals in the Republic of the Congo (Boutellis et al, 2013b;Amanzougaghene et al, 2016a). The Y. pestis DNA was also found in clade A head lice infesting individuals from a highly endemic plague area in the eastern Congo (Piarroux et al, 2013;Drali et al, 2015b).…”

“…Clade C has been reported mainly from two continents, Africa (from Ethiopia and the Republic of Congo) and Asia (Nepal, Pakistan, and Thailand) (Sunantaraporn et al, 2015;Amanzougaghene et al, 2016aAmanzougaghene et al, , 2017. Lastly, clade E was chiefly found in head lice from West African countries (in Senegal and Mali) (Amanzougaghene et al, 2017(Amanzougaghene et al, , 2019.…”

“…Six mitochondrial clades were described (A, D, B, F, C, and E) (Ashfaq et al, 2015;Drali et al, 2015b;Amanzougaghene et al, 2016bAmanzougaghene et al, , 2017Amanzougaghene et al, , 2019. In addition to the inter clade diversity, human lice also display intra clade diversity, as illustrated by the multiple distinct haplotypes for each clade ( Figure 1B) (Ascunce et al, 2013;Ashfaq et al, 2015;Amanzougaghene et al, 2016a;Drali et al, 2016a). Head lice encompass all clades diversity, while body lice belong to clades A and D only (Amanzougaghene et al, 2017).…”

“…Clade A is widely and globally distributed, while clade D has so far only been reported in sub-Saharan African countries, including the Democratic Republic of Congo (DRC) and the Republic of Congo (Congo-Brazzaville), where it was characterized for the first time among the Pygmy populations (Ascunce et al, 2013;Ashfaq et al, 2015;Drali et al, 2015b;Amanzougaghene et al, 2016a). The clade D was also found in Zimbabwe and Ethiopia (Amanzougaghene et al, 2016a(Amanzougaghene et al, , 2019. Clade B is mainly found in America, where it exhibits a high diversification (Reed et al, 2004;Light et al, 2008a;Ascunce et al, 2013).…”

A case of severe pediculosis capitis

“…Pediculosis capitis may cause skin irritation, secondary infection from scratching, social stigmatization, and psychological distress. Recent studies suggest that head lice, as is the case of body lice, could act as a vector for louse‐borne diseases …”