Helicobacter pylori virulence factors as tools to study human migrations.
Helicobacter pylori is one of the most common infections worldwide. In most individuals it consists in a lifelong host-pathogen relationship without consequences, but in some subjects it is associated with peptic ulcer disease and gastric cancer. Polymorphism in genes that code bacterial virulence factors, cagA and vacA, are independently associated with the infection severe outcomes and are geographically diverse. In the last decade, accumulated knowledge allowed to characterize typical H. pylori strain patterns for all the major human populations; patterns that can be used to study the origin of specific human groups. Thus, the presence or absence of cagA, cagA EPIYA genotypes, and vacA subtypes can be used as tools to study not only the geographic origin of specific human populations, but also to identify markers of historical contact between different ethnicities. We report here a study including a set of native Amazon Amerindians that had supposedly been some, but little, contact with European Brazilian colonizer and/or African slaves. They harbor H. pylori strains in a mixed pattern with Asian and Iberian Peninsula characteristics. It is possible that this finding represents H. pylori recombination upon short contact between human groups. Alternatively, it could be due to a founder effect from a small cluster of Asian origin native Americans.
Laboratory of Research in Bacteriology, Faculdade de Medicina, Universidade Federal de Minas Gerais. Av. Alfredo Balena 190/216., 30130-100 Belo Horizonte, MG, Brazil. dqueiroz@medicina.ufmg.br
Dulciene Maria de Magalhães
DM
Queiroz
Roberto Penna de Almeida
RP
Cunha
Ivan Euclides Borges
IE
Saraiva
Andreia Maria Camargos
AM
Rocha
D000942:Antigens, Bacterial / Q000235:genetics; D044466:Asian People; D001426:Bacterial Proteins / Q000235:genetics; D001938:Brazil; D004641:Emigration and Immigration; D005843:Geography; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D007199:Indians, South American; D037521:Virulence Factors / Q000235:genetics*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori