New Insights into the Geographic Distribution of Mycobacterium leprae SNP Genotypes Determined for Isolates from Leprosy Cases Diagnosed in Metropolitan France and French Territories

Abstract

BackgroundBetween 20 and 30 bacteriologically confirmed cases of leprosy are diagnosed each year at the French National Reference Center for mycobacteria. Patients are mainly immigrants from various endemic countries or living in French overseas territories. We aimed at expanding data regarding the geographical distribution of the SNP genotypes of the M. leprae isolates from these patients.Methodology/Principal findingsSkin biopsies were obtained from 71 leprosy patients diagnosed between January 2009 and December 2013. Data regarding age, sex and place of birth and residence were also collected. Diagnosis of leprosy was confirmed by microscopic detection of acid-fast bacilli and/or amplification by PCR of the M. leprae-specific RLEP region. Single nucleotide polymorphisms (SNP), present in the M. leprae genome at positions 14 676, 1 642 875 and 2 935 685, were determined with an efficiency of 94% (67/71). Almost all patients were from countries other than France where leprosy is still prevalent (n = 31) or from French overseas territories (n = 36) where leprosy is not totally eradicated, while only a minority (n = 4) was born in metropolitan France but have lived in other countries. SNP type 1 was predominant (n = 33), followed by type 3 (n = 17), type 4 (n = 11) and type 2 (n = 6). SNP types were concordant with those previously reported as prevalent in the patients’ countries of birth. SNP types found in patients born in countries other than France (Comoros, Haiti, Benin, Congo, Sri Lanka) and French overseas territories (French Polynesia, Mayotte and La Réunion) not covered by previous work correlated well with geographical location and history of human settlements.Conclusions/SignificanceThe phylogenic analysis of M. leprae strains isolated in France strongly suggests that French leprosy cases are caused by SNP types that are (a) concordant with the geographic origin or residence of the patients (non-French countries, French overseas territories, metropolitan France) or (b) more likely random in regions where diverse migration flows occurred.

Population Genomics of Mycobacterium leprae Reveals a New Genotype in Madagascar and the Comoros

“…In summary, branch 4 strains seem to be restricted to West Africa, whereas branches 2E, 2F, and 2H are present in East Africa, including Ethiopia (2E, 2F, and 2H) and Malawi (2E) (Monot et al, 2009;Benjak et al, 2018). Strains from branches 1 and 2 have been reported in the Congo (Reibel et al, 2015), while branch 3 strains, notably of genotype 3I, have been described in Morocco and Egypt (Monot et al, 2009). The canonical SNP type 1D is found in 12 countries outside Africa (Monot et al, 2009;Benjak et al, 2018).…”

“…In Madagascar and the Comoros, little is known about the genetic background of circulating M. leprae strains. Two epidemiological studies reported the presence of the genotype 1D in Madagascar, but only seven isolates were studied so far (Monot et al, 2009;Reibel et al, 2015). No information is available about the strains currently circulating in the Comoros.…”

British Red Squirrels Remain the Only Known Wild Rodent Host for Leprosy Bacilli

“…Great Britain, Germany, Switzerland and France have been free of autochthonous human leprosy cases for decades or even centuries (14, 25–27), while autochthonous cases have been noted in more recent times in Italy (28). There are no obvious reasons why continental Eurasian red squirrels are less likely to have had contact with leprosy bacilli from a human source in the past than British squirrels, especially in countries where autochthonous human cases, albeit rare, still appear.…”

Seek and Find! PCR analyses of skin infections in West-European travelers returning from abroad with an eschar

“…One Mycobacterium leprae infection was acquired in the Comoros. A French study conducted from 2009 to 2013 reported that the Comoros were the main focus of Mycobacterium leprae infections diagnosed in France [24], while in a study conducted in Madrid, from 1989 to 2015, most cases were migrants from South America [25] and in a Danish study conducted from 1980 to 2010, most cases were migrants from South-East Asia [26]. In our study, one Bartonella henselae case was diagnosed in a patient returning from Morocco, a disease rarely described in Morocco [27][28][29][30], while fleas have been shown to be positive for Bartonella henselae in this country [31].…”