Temporal-Spatial Distribution of Vibrio cholerae in Cuba: July 1997-December 2019.

INTRODUCTION

Vibrio cholerae is a microorganism that causes acute diarrheal diseases and cholera, one of the leading causes of global morbidity and mortality, especially in children under five years old. It is present in many regions and has been isolated from diverse sources such as water, soil and food. Surveillance of this microorganism in Cuba from 1985 through June 1997 showed circulation of non-epidemic non-O1/non-O139 serogroups, but surveillance continued to identify distribution of V. cholerae serotypes and serogroups in the different geographic regions of the country during the following years, due to the risk of introducing cholera-causing serogroups that provoked cholera epidemics in other countries of the region.

OBJECTIVE

Describe the temporal‒spatial distribution of serogroups and serotypes of V. cholerae in Cuba.

METHODS

A cross-sectional study was conducted that included isolates from passive surveillance of V. cholerae in 16 hygiene and epidemiology centers throughout Cuba from July 1997 through December 2019, submitted to the National Reference Laboratory for Acute Diarrheal Diseases of the Pedro Kourí Tropical Medicine Institute in Havana, Cuba. The timeline was subdivided into three five-year periods and one eight-year period. The centers submitting isolates were grouped into three geographical regions: western, central and eastern Cuba. A total of 1060 V. cholerae isolates were studied, from the 1438 samples sent from 15 Provincial Hygiene, Epidemiology and Microbiology Centers and the Municipal Hygiene, Epidemiology and Microbiology Center of the Isle of Youth Special Municipality. Genus, species and serotype of all specimens were studied and reviewed in the context of the outbreaks of acute diarrheal diseases reported in the country.

RESULTS

All 1060 isolates were confirmed as V. cholerae. In the distribution by time period and region, the highest percentage occurred in the 2012‒2019 period, and the eastern region contributed the most isolates in all periods. Approximately 63.9% (677/1060) were from outbreaks, and in the 2012‒2019 period, the most epidemic-causing isolates came from the western region. Approximately 52.8% (560/1060) were identified as non-O1/non-O139 V. cholerae, and 47.2% (500/1060) as O1 V. cholerae; of these, 96.4% (482/500) corresponded to Ogawa serotype and 3.6% (18/500) to Inaba. Circulation of non-O1/non-O139 V. cholerae occurred throughout the entire period. The O1 serogroup began to circulate in 2012 and continued through 2016; however, since 2017, it has not been identified again. In the western region, there were smaller percentages of isolates of non-O1/non-O139 V. cholerae in all periods, except 2012‒2019. In that period, V. cholerae O1 was identified to a lesser degree in the central region.

CONCLUSIONS

Vibrio cholerae circulated in all three Cuban regions during the years studied, with a higher percentage of isolates of the non-O1/non-O139 serogroup, which caused outbreaks or sporadic cases of diarrhea in the eastern region, with the exception of the 2012‒2019 period, when epidemic outbreaks of the O1 serogroup (which causes cholera) occurred in all three regions, with higher percentages in the western region.