High Seroprevalence of Helicobacter pylori and CagA/VacA Virulence Factors in Northern Central America

Abstract

Background: Northern Central America is unique in the Western Hemisphere, with a high incidence of gastric cancer, low/middle-income country (LMIC) status, and a substantial emigration to the United States. The two primary Helicobacter pylori (H. pylori) virulence factors related to carcinogenesis are cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA). The prevalence of these factors may help delineate gastric cancer risk in the region. We aimed to characterize the H. pylori seroprevalence and virulence factors in two Central American Countries (Honduras and Guatemala).

Methods: Healthy volunteers from Western Honduras and Central-Western Guatemala were recruited and tested for antibodies against 13 H. pylori antigens using a novel multiplex serology assay. H. pylori seropositivity was defined as positivity for ≥ 4 antigens, and active infection was defined as positivity for a combination of 2/4 antigens: VacA, GroEl, HcpC, and HP1564, based upon the literature. Multivariate logistic regression models were used to estimate the odds ratios for the association between H. pylori and CagA positivity.

Results: A total of 1,143 healthy adults were tested using the H. pylori multiplex serology assay (444 in Guatemala and 699 in Honduras). Mean age was 54.2 ± 14.5 years, 46.2% were male, 60% were from rural settings, and 56% lived > 1,000 meters above sea level. H. pylori prevalence was 87%, and 83% with active infection. The CagA and VacA seropositivity rates were 82% and 75%, respectively. No significant differences were noted according to country, age group, sex, or rural/urban location. None of the socioeconomic variables were significantly associated with the presence of H. pylori or CagA.

Conclusions: A high prevalence of H. pylori, CagA, and VacA is observed in Honduras and Guatemala, with implications for Northern Central America and immigrants from the region. Innovative and resource-appropriate primary and secondary prevention programs are needed.

Keywords: CagA; Central America; Gastric cancer; Helicobacter pylori; VacA.

Figure 1

Sampling locations and participant recruitment across Northern Central America. This figure depicts the distribution and response rates of the subjects invited to participate in the study conducted in Northern Central America. In total, 1,143 participants were invited from various urban and rural centers within Guatemala and Honduras. The map highlights Guatemala with two urban centers and three rural centers, where 444 of the 461 subjects completed the serology tests. Similarly, in Honduras, all 699 invited subjects from three rural centers completed the tests. The shaded areas indicate the regions where the subjects were sampled, and the details provided within the insets specify the number of participants and completion rates of serological testing.

Figure 2

Prevalence of H. pylori, CagA, and VacA seropositivity by country (N = 1,143). This figure presents the prevalence rates of H. pylori serostatus and associated virulence factors among the populations sampled in Honduras and Guatemala. The bar chart compares the positive rates of H. pylori serostatus, active infection, and the presence of CagA and VacA virulence factors between the two countries as well as the total combined prevalence.

Figure 3

H. pylori and CagA seropositivity by age groups (N = 1,143). This figure illustrates the distribution of H. pylori and CagA seropositivity across different age groups among the 1,143 individuals sampled. The stacked bar chart shows the percentages of participants who were H. pylori-positive with and without CagA positivity (shown in darker and lighter shades of blue, respectively) and those who were H. pylori-negative (shown in green). Age groups were segmented as 18 - 30, 30 - 39, 40 - 49, 50 - 59, 60 - 69, and over 65 years (*Honduras participants only).