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.

Protective effect of house screening against indoor Aedes aegypti in Mérida, Mexico: A cluster randomised controlled trial.

OBJECTIVE: To evaluate the protective effect of house screening (HS) on indoor Aedes aegypti infestation, abundance and arboviral infection in Merida, Mexico. METHODS: In 2019, we performed a cluster randomised controlled trial (6 control and 6 intervention areas: 100 households/area). Intervention clusters received permanently fixed fiberglass HS on all windows and doors. The study included two cross-sectional entomologic surveys, one baseline (dry season in May 2019) and one post-intervention (PI, rainy season between September and October 2019). The presence and number of indoor Aedes females and blood-fed females (indoor mosquito infestation) as well as arboviral infections with dengue (DENV) and Zika (ZIKV) viruses were evaluated in a subsample of 30 houses within each cluster. RESULTS: HS houses had significantly lower risk for having Aedes aegypti female mosquitoes (odds ratio [OR] = 0.56, 95% CI 0.33-0.97, p = 0.04) and blood-fed females (OR = 0.53, 95% CI 0.28-0.97, p = 0.04) than unscreened households from the control arm. Compared to control houses, HS houses had significantly lower indoor Ae. aegypti abundance (rate ratio [RR] = 0.50, 95% CI 0.30-0.83, p = 0.01), blood-fed Ae. aegypti females (RR = 0.48, 95% CI 0.27-0.85, p = 0.01) and female Ae. aegypti positive for arboviruses (OR = 0.29, 95% CI 0.10-0.86, p = 0.02). The estimated intervention efficacy in reducing Ae. aegypti arbovirus infection was 71%. CONCLUSIONS: These results provide evidence supporting the use of HS as an effective pesticide-free method to control house infestations with Aedes aegypti and reduce the transmission of Aedes-transmitted viruses such as DENV, chikungunya (CHIKV) and ZIKV.

Safety and immunogenicity of the Cuban heptavalent pneumococcal conjugate vaccine in healthy infants. Results from a double-blind randomized control trial Phase I.

BACKGROUND: Cuba has a new pneumococcal conjugate vaccine candidate (PCV7-TT). This study evaluates the safety and immunogenicity in healthy infants using 2p+1 vaccination schedule. METHODS: A phase I, controlled, randomized and double blind clinical trial was designed. 30 unvaccinated healthy infants were included. 20 subjects were assigned to study group (PCV7-TT) and 10 to control group (Synflorix®) to receive the vaccines at 7, 8 months of age (primary series) and 11 months (booster dose). Blood samples were collected 30 days after second dose and post booster for antibodies measure analysis by ELISA and OPA. The statistics analysis included the frequency of occurrence for adverse events and the immune response. Non-parametric tests were used to compare the immune response. The clinical trial was published in the Cuban Public Register of Clinical Trials with code RPCEC00000173 available at http://registroclinico.sld.cu. RESULTS: Overall, the safety profile of PCV7-TT was similar to Synflorix®. Local reactions were predominant and systemic events were mild in severity. Swelling and redness were frequently associated with PCV7-TT mainly after the first dose (50% and 40% respectively). 15% and 10% of subject reported severe swelling after first dose with PCV7-TT and after second dose with Synflorix®. Mild fever (≥38-≤39), vomiting and sleep disturb were the systemic events reported. 100% of infants achieved pneumococcal IgG antibody concentrations ≥0.35 µg/ml after booster dose for serotypes 1, 14, 18C and 19F in each vaccine group. For serotypes 5, 6B and 23F, more than 80% infants vaccinated with Synflorix® or PCV7-TT achieved protective IgG GMC ≥ 0.35 µg/ml after booster dose. OPA proportion's responders to the seven common serotypes were 89.5% or more after the primary dose and 100% after booster dose in vaccinated with PCV7-TT. CONCLUSIONS: The Cuban PCV7-TT is safe, well tolerated and immunogenic in healthy infants.

From individual to herd protection with pneumococcal vaccines: the contribution of the Cuban pneumococcal conjugate vaccine implementation strategy.

A new pneumococcal conjugate vaccine is currently undergoing advanced clinical evaluation prior to its planned introduction in Cuba. The implementation of the pneumococcal vaccination strategy has been designed with consideration of the need to maximize both its direct and indirect effects. A novel approach is suggested, which addresses preschool children as the first-line target group to generate herd immunity in infants and to have an impact on transmission at the community level. The clinical evaluation pipeline is described herein, including evaluations of effectiveness, cost-effectiveness, and impact. The scientific contribution of the Cuban strategy could support a paradigm shift from individual protection to a population effect based on a rigorous body of scientific evidence.

Achieving sustainability of community-based dengue control in Santiago de Cuba.

Achieving sustainability is one of the major current challenges in disease control programmes. In 2001-2002, a community-based dengue control intervention was developed in three health zones of Santiago de Cuba. New structures (heterogeneous community working groups and provincial/municipal coordination groups inserted in the vertical programme) were formed and constituted a key element to achieve social mobilization. In three control zones, routine programme activities were intensified. We evaluated the sustainability of the intervention strategy over a period of 2 years after the withdrawal of external support. Data on maintenance of effects, level of institutionalization and continuity of activities through capacity building were collected via documental review, direct observation, questionnaires, key informant and group interviews and routine entomological surveys. The intervention effects, evaluated through larval indices and behavioural change indicators, were maintained during the 2 years of follow-up. In the intervention area, 87.5% of the water storage containers remained well covered in 2004 and 90.5% of the families continued to correctly use a larvicide, against 21.5% and 63.5%, respectively in the control area. The house indices further declined from 0.35% in 2002 to 0.17% in 2004 in the intervention area, while in the control area they increased from 0.52% to 2.25%. Institutionalization of the intervention, assessed in terms of degrees of intensiveness (passage, routine, niche saturation), was reaching saturation by the end of the study. Key elements of the intervention had lost their separate identity and became part of the control programme's regular activities. The host organization adapted its structures and procedures accordingly. Continuous capacity building in the community led to participatory planning, implementation and evaluation of the Aedes control activities. It is concluded that, in contrast to intensified routine control activities, a community-based intervention approach promises to be sustainable.