RESUMO
Burkholderia pseudomallei, the etiological agent of melioidosis, has been hypothesized to be endemic throughout the Caribbean, including the impoverished nation of Haiti. However, because of the protean clinical manifestations, presence of asymptomatic infections, and limited medical diagnostic capacity, the identification of active melioidosis cases remains challenging. A seroepidemiological study was conducted using a novel enzyme-linked immunosorbent assay (ELISA) to detect antibodies toward B. pseudomallei in the native population. The performance of an indirect ELISA with purified lipopolysaccharide (LPS) from B. pseudomallei was evaluated using serum collected from rhesus macaques exposed to aerosolized B. pseudomallei. After optimization, serum collected from asymptomatic population members (n = 756) was screened for polyvalent (immunoglobulin M [IgM]/ immunoglobulin G [IgG]/ immunoglobulin A) and monoclonal (IgG or IgM) immunoglobulins against B. pseudomallei LPS. The population seroprevalence was 11.5% (95% confidence interval [CI]: 9.2, 13.8) for polyvalent immunoglobulins, 9.8% (95% CI: 7.7, 11.9) for IgG, and 1.7% (95% CI: 0.8, 2.6%) for IgM. The seroprevalence was not significantly different by gender (P = 0.16), but increased significantly (P < 0.001) with age, yielding an estimated annual seroconversion rate of 1.05% (95% CI: 0.81, 1.3). The detection of both recent (IgM+) and previous (IgG+) exposure to B. pseudomallei provides serological evidence that melioidosis is endemic in Haiti.
Assuntos
Anticorpos Antibacterianos/sangue , Burkholderia pseudomallei/imunologia , Melioidose/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Animais , Infecções Assintomáticas/epidemiologia , Criança , Pré-Escolar , Doenças Endêmicas , Ensaio de Imunoadsorção Enzimática , Feminino , Haiti/epidemiologia , Humanos , Lipopolissacarídeos , Macaca mulatta/imunologia , Masculino , Melioidose/imunologia , Pessoa de Meia-Idade , Estudos Soroepidemiológicos , Adulto JovemRESUMO
BACKGROUND: According to the 2016 World Malaria Report, the malaria incidence in Haiti declined by > 40% between 2010 and 2015. Though elimination efforts have likely contributed, this time period also corresponded to a national change in diagnostic methods. METHODS: Monthly reports of aggregated patient data were acquired from five clinics in the Ouest Department of Haiti. Generalized linear models were used to compare the number of febrile patients tested, the number of positive tests, and the proportion of tests that were positive (TRP) before and after the national adoption of rapid diagnostic tests (RDTs). RESULTS: Prior to the earthquake when microcopy was used for diagnosis, a total of 1,727 patients with 557 (32.3%) positive; post-earthquake testing was reduced and the TPR was variable; during the post recovery period when RDTs were used exclusivly, a total of 5,132 patients were tested using RDTs, only 83 (1.62%) were positive. Compared to the pre-earthquake period, there was a 69% increase in the number of patients tested (IRR: 1.69; 95% CI IRR 1.59, 2.79), and a 97.0% decrease in the proportion of patients with a positive test result (IRR: 0.03; 95% CI IRR 0.02, 0.04) in the post-recovery period. CONCLUSIONS: While the decline in malaria indicators between 2010 and 2015 has been cited as evidence of progress towards elimination, these reports derived estimates of the malaria burden in Haiti using two different diagnostic tests. Thus, comparison of these periods in the context of malaria elimination should be made with caution.
Assuntos
Testes Diagnósticos de Rotina/tendências , Malária/diagnóstico , Terremotos , Haiti , Humanos , Microscopia , Fatores de TempoRESUMO
Throughout many developing and tropical countries around the world, malaria remains a significant threat to human health. One barrier to malaria elimination is the ability to safely administer primaquine chemotherapy for the radical cure of malaria infections in populations with a high prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency. In the current study, a field trial of the world's first quantitative, point-of-care assay for measuring G6PD activity was conducted in Haiti. The performance of the CareStart Biosensor Analyzer was compared with the gold standard spectrophotometric assay and genotyping of the G6PD allele in schoolchildren (N = 343) from the Ouest Department of Haiti. In this population, 19.5% of participants (67/343) had some form of G6PD deficiency (< 60% residual activity) and 9.9% (34/343) had moderate-to-severe G6PD deficiency (< 30% residual activity). Overall, 18.95% of participants had the presence of the A-allele (65/343) with 7.87% (27/343) considered at high risk for drug-induced hemolysis (hemizygous males and homozygous females). Compared with the spectrophotometric assay, the sensitivity and specificity to determine participants with < 60% residual activity were 53.7% and 94.6%, respectively; for participants with 30% residual activity, the sensitivity and specificity were 5.9% and 99.7%, respectively. The biosensor overestimated the activity in deficient individuals and underestimated it in participants with normal G6PD activity, indicating the potential for a systematic measurement error. Thus, we suggest that the current version of the biosensor lacks adequate sensitivity and should be improved prior to its use as a point-of-care diagnostic for G6PD deficiency.
Assuntos
Técnicas Biossensoriais , Glucosefosfato Desidrogenase/metabolismo , Malária/diagnóstico , Malária/epidemiologia , Alelos , Antimaláricos/administração & dosagem , Antimaláricos/efeitos adversos , Criança , Feminino , Genótipo , Glucosefosfato Desidrogenase/genética , Haiti , Humanos , Masculino , Sistemas Automatizados de Assistência Junto ao Leito , Primaquina/administração & dosagem , Primaquina/efeitos adversosRESUMO
OBJECTIVES: To describe the epidemiology of malaria in pregnancy in Haiti. METHODS: Cross-sectional study among pregnant women in six departments of Haiti. After obtaining informed consent, whole blood samples and demographic surveys were collected to investigate malaria prevalence, anaemia and socio-behavioural risk factors for infection, respectively. A total of 311 pregnant women were screened for Plasmodium falciparum infection using a rapid diagnostic test (RDT), microscopy and a novel, quantitative reverse transcriptase polymerase chain reaction method (qRT-PCR). RESULTS: Overall, 1.2% (4/311) of pregnant women were tested positive for malaria infection by both microscopy and RDT. However, using the qRT-PCR, 16.4% (51/311) of pregnant women were positive. The prevalence of malaria infection varied with geographical locations ranging between 0% and 46.4%. Additionally, 53% of pregnant women had some form of anaemia; however, no significant association was found between anaemia and submicroscopic malaria infection. The socio-behavioural risk factors identified to be protective of malaria infection were marital status (P < 0.05) and travel within one month prior to screening (P < 0.05). CONCLUSION: This study is the first to document the high prevalence of submicroscopic malaria infections among pregnant women in Haiti and identify social and behavioural risk factors for disease transmission.
Assuntos
Malária Falciparum/epidemiologia , Plasmodium falciparum , Complicações Infecciosas na Gravidez/epidemiologia , Adolescente , Adulto , Anemia/complicações , Estudos Transversais , Feminino , Haiti/epidemiologia , Humanos , Malária Falciparum/parasitologia , Malária Falciparum/transmissão , Estado Civil , Microscopia , Gravidez , Complicações Infecciosas na Gravidez/parasitologia , Prevalência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Viagem , Adulto JovemRESUMO
Following the 2010 cholera outbreak in Haiti, a plan was initiated to provide massive improvements to the sanitation and drinking water infrastructure in order to eliminate cholera from the island of Hispaniola by 2023. Six years and a half billion dollars later, there is little evidence that any substantial improvements have been implemented; with increasing evidence that cholera has become endemic. Thus, it is time to explore strategies to control cholera in Haiti using oral cholera vaccines (OCVs). The potential effects of mass administration of OCVs on cholera transmission were assessed using dynamic compartment models fit to cholera incidence data from the Ouest Department of Haiti. The results indicated that interventions using an OCV that was 60% effective could have eliminated cholera transmission by August 2012 if started five weeks after the initial outbreak. A range of analyses on the ability of OCV interventions started January 1, 2017 to eliminate cholera transmission by 2023 were performed by considering different combinations of vaccine efficacies, vaccine administration rates, and durations of protective immunity. With an average of 50 weeks for the waiting time to vaccination and an average duration of three years for the vaccine-induced immunity, all campaigns that used an OCV with a vaccine efficacy of at least 60% successfully eliminated cholera transmission by 2023. The results of this study suggest that even with a relatively wide range of vaccine efficacies, administration rates, and durations of protective immunity, future epidemics could be controlled at a relatively low cost using mass administration of OCVs in Haiti.
Assuntos
Vacinas contra Cólera/administração & dosagem , Cólera/epidemiologia , Cólera/prevenção & controle , Erradicação de Doenças , Transmissão de Doença Infecciosa/prevenção & controle , Administração Oral , Haiti/epidemiologia , Humanos , Modelos EstatísticosRESUMO
Though plans to eliminate malaria from the island of Hispaniola have recently received much attention, arbovirus surveillance continues to be largely neglected in Haiti. To support surveillance efforts and encourage vector-control strategies, a cross-sectional study of dengue virus (DENV) and West Nile virus (WNV) transmission was conducted using standard seroepidemiological methods. Blood samples (N = 673) were collected from 278 males and 395 females from three locations in the Ouest and Sud-Est Departments of Haiti. Serum was separated and tested for the presence of anti-DENV and anti-WNV immunoglobulin G (IgG) antibodies using an indirect enzyme-linked immunosorbent assay (ELISA). Anti-DENV IgG antibodies were detected in 72.1% (95% confidence interval [CI] = 68.7, 75.5) of the sample population; with no significant differences in seroprevalence by study location, participant gender, or age group (P > 0.1, in all tests). Anti-WNV IgG antibodies were detected in only 1% (95% CI = 0.3, 1.8) of the sample population, all which originated from participants located in Gressier. The high prevalence of anti-DENV IgG antibodies among all age groups, including those in the youngest age group (2-5 years of age), suggests hyperendemic transmission of DENV in the Ouest and Sud-Est Departments of Haiti. In contrast, the relative absence of anti-WNV IgG antibodies, even among older population members, further supports the notion that WNV transmission in this population is largely absent. These findings highlight the large burden of disease from DENV and the need for enhanced arbovirus surveillance and implementation of vector control strategies throughout Haiti.
Assuntos
Dengue/transmissão , Dengue/virologia , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/transmissão , Febre do Nilo Ocidental/virologia , Adolescente , Adulto , Envelhecimento , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Vírus da Dengue , Feminino , Haiti/epidemiologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Vírus do Nilo Ocidental , Adulto JovemRESUMO
BACKGROUND: Plasmodium vivax infections, while quite prevalent throughout South and Central America, are virtually non-existent in Haiti, where P. falciparum infections are detected in over 99% of malaria cases. Historically, few cases of P. vivax have been reported in Haiti; all of which were identified by microscopy and none were confirmed by molecular diagnostics. To further examine the transmission of P. vivax in Haiti, a cross-sectional seroepidemiological study was conducted. METHODS: Whole blood was collected from 814 community members and school children ranging in age between 2 and 80 years-of-age from four locations in the Ouest and Sud-Est Departments of Haiti. After separation of serum, samples were screened for antibodies toward P. vivax apical membrane antigen (AMA-1) and merozoite surface protein-119 (MSP-1) using an indirect enzyme-linked immunosorbent assay (ELISA). RESULTS: Of all participants screened, 4.42% (36/814) were seropositive for AMA-1, 4.55% (37/814) were seropositive for MSP-1, 7.99% (65/814) were seropositive to either antigen, and only 0.98% (7/814) were seropositive for both antigens. Seroconversion rates (SCR) for AMA-1, MSP-1, either AMA-1 or MSP-1, and for both AMA-1 and MSP-1 estimated from the cross-sectional seroprevalence indicated rates of P. vivax transmission of less than 1% per year. CONCLUSION: Given the lack of historical evidence of P. vivax infections on the island of Hispaniola, the sparse serological evidence of antibodies toward P. vivax identified in the current study further support the notion that the transmission of P. vivax malaria might be extremely low or even completely absent in Haiti.
Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/sangue , Imunoglobulina G/sangue , Malária Vivax/imunologia , Malária Vivax/transmissão , Plasmodium vivax/imunologia , Plasmodium vivax/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Membrana Celular , Criança , Pré-Escolar , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Haiti/epidemiologia , Humanos , Imunoglobulina G/imunologia , Malária Vivax/epidemiologia , Masculino , Proteínas de Membrana/sangue , Proteínas de Membrana/imunologia , Proteína 1 de Superfície de Merozoito/sangue , Proteína 1 de Superfície de Merozoito/imunologia , Pessoa de Meia-Idade , Prevalência , Estudos Soroepidemiológicos , Adulto JovemRESUMO
Motivated by an investigation of the effect of surface water temperature on the presence of Vibrio cholerae in water samples collected from different fixed surface water monitoring sites in Haiti in different months, we investigated methods to adjust for unmeasured confounding due to either of the two crossed factors site and month. In the process, we extended previous methods that adjust for unmeasured confounding due to one nesting factor (such as site, which nests the water samples from different months) to the case of two crossed factors. First, we developed a conditional pseudolikelihood estimator that eliminates fixed effects for the levels of each of the crossed factors from the estimating equation. Using the theory of U-Statistics for independent but non-identically distributed vectors, we show that our estimator is consistent and asymptotically normal, but that its variance depends on the nuisance parameters and thus cannot be easily estimated. Consequently, we apply our estimator in conjunction with a permutation test, and we investigate use of the pigeonhole bootstrap and the jackknife for constructing confidence intervals. We also incorporate our estimator into a diagnostic test for a logistic mixed model with crossed random effects and no unmeasured confounding. For comparison, we investigate between-within models extended to two crossed factors. These generalized linear mixed models include covariate means for each level of each factor in order to adjust for the unmeasured confounding. We conduct simulation studies, and we apply the methods to the Haitian data. Copyright © 2016 John Wiley & Sons, Ltd.
Assuntos
Interpretação Estatística de Dados , Modelos Logísticos , Simulação por Computador , Fatores de Confusão Epidemiológicos , Haiti , Modelos Lineares , Vibrio cholerae/isolamento & purificação , Abastecimento de ÁguaRESUMO
[This corrects the article DOI: 10.1371/journal.pntd.0004153.].
RESUMO
BACKGROUND: Public health measures are poised for transition from malaria control to malaria elimination on the island of Hispaniola. Assessment of the reservoir of asymptomatic infections from which acute malaria cases may derive is critical to plan and evaluate elimination efforts. Current field technology is ill suited for detecting sub-microscopic infections, thus highly sensitive survey methods capable of detecting virtually all infections are needed. In this study the prevalence of infection with Plasmodium falciparum was determined in patients seeking medical care primarily for non-febrile conditions in six departments in Haiti using a newly designed qRT-PCR-based assay. METHODS: Three different methods of parasite detection were compared to assess their utility in approximating the prevalence of P. falciparum infections in the population: malaria rapid diagnostic test (RDT) designed to detect histidine-rich protein 2 (HRP2), thick smear microscopy, and a quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay based upon the small sub-unit ribosomal RNA. The limit of detection of the qRT-PCR assay utilized was 0.0003 parasite/µL of blood. Venous blood was obtained from a total of 563 subjects from six departments in Haiti, all of whom were seeking medical attention without complaints consistent with malaria. Each subject was questioned for knowledge and behaviour using demographic and epidemiological survey to identify risk factors for disease transmission. RESULTS: Among the 563 samples tested, ten and 16 were found positive for malaria by RDT and microscopy, respectively. Using the qRT-PCR test to assess the infection status of these subjects, an additional 92 were identified for a total of 108. Based upon the qRT-PCR assay results, a wide variation in prevalence of infection in asymptomatic subjects was seen between geographic locations ranging from 4-41%. The prevalence of infection was highest in the Grand Anse, Nord and Sud-Est Departments, and demographic data from questionnaires provide evidence for focal disease transmission. CONCLUSIONS: The qRT-PCR assay is sufficiently sensitive to identify an unexpectedly large number of asymptomatic, submicroscopic infections. Identifying and clearing these infections presents a significant challenge to both control and elimination efforts, but the qRT-PCR assay offers a reliable method to identify them.