BackgroundRecently, a real-time PCR assay known as photo-induced electron transfer (PET)-PCR which relies on self-quenching primers for the detection of Plasmodium spp. and Plasmodium falciparum was described. PET-PCR assay was found to be robust, and easier to use when compared to currently available real-time PCR methods. The potential of PET-PCR for molecular detection of malaria parasites in a nationwide malaria community survey in Haiti was investigated.MethodsDNA from the dried blood spots was extracted using QIAGEN methodology. All 2,989 samples were screened using the PET-PCR assay in duplicate. Samples with a cycle threshold (CT) of 40 or less were scored as positive. A subset of the total samples (534) was retested using a nested PCR assay for confirmation. In addition, these same samples were also tested using a TaqMan-based real-time PCR assay.ResultsA total of 12 out of the 2,989 samples screened (0.4%) were found to be positive by PET-PCR (mean CT value of 35.7). These same samples were also found to be positive by the nested and TaqMan-based methods. The nested PCR detected an additional positive sample in a subset of 534 samples that was not detected by either PET-PCR or TaqMan-based PCR method.ConclusionWhile the nested PCR was found to be slightly more sensitive than the PET-PCR, it is not ideal for high throughput screening of samples. Given the ease of use and lower cost than the nested PCR, the PET-PCR provides an alternative assay for the rapid screening of a large number of samples in laboratory settings.

BackgroundAs a nation reduces the burden of falciparum malaria, identifying areas of transmission becomes increasingly difficult. Over the past decade, the field of utilizing malaria serological assays to measure exposure has grown rapidly, and a variety of serological methods for data acquisition and analysis of human IgG against falciparum antigens are available. Here, different immunoassays and statistical methods are utilized to analyse samples from a low transmission setting and directly compare the estimates generated.MethodsA subset of samples (n = 580) from a 2012 Haitian nationwide malaria survey was employed as sample population of low falciparum endemicity. In addition to the Haitian samples, samples from 247 US residents were used as a reference population of ‘true seronegatives’. Data acquisition was performed through standard ELISA and bead-based multiplex assays assaying for IgG antibodies to the Plasmodium falciparum antigens MSP-1p19, MSP-1p42(D), MSP-1p42(F), and AMA-1. Appropriate parametric distributions and seropositivity cutoff values were determined by statistical measures.ResultsData from both assays showed a strong positive skew, and the lognormal distribution was found to be an appropriate statistical fit to the Haitian and American populations. The American samples served as a good serological true negative population for the multiplex assay, but not for ELISA-based data. Mixture model approaches to determine seronegative and seropositive populations from the Haitian data showed a high degree of distribution overlap—likely due to the historical low falciparum transmission in this nation. Different fittings to the reversible catalytic model resulted depending upon the immunoassay utilized and seropositivity cutoff method employed. Data were also analysed through fitting to penalized B-splines, presenting another possible analytical tool for the analysis of malaria serological data.ConclusionsStandardization of serological techniques and analyses may prove difficult as some tools can prove to be more useful depending on the area and parasite in question, making clear interpretation a vital pursuit. The presented analysis in the low-endemic nation of Haiti found malaria-naive US residents to be an appropriate seronegative reference population for the multiplex assay, and this assay providing consistent estimates between MSP-1 and AMA-1 antigens of percent seropositives for this low-endemic population.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0955-1) contains supplementary material, which is available to authorized users.

The Global Fund to Fight AIDS, Tuberculosis, and Malaria, and the US-based Centers for Disease Control and Prevention (CDC).

BACKGROUND: There is limited information on depression in Haitians and this is partly attributable to the absence of culturally and linguistically adapted measures for depression. OBJECTIVE: To perform a psychometric evaluation of the Haitian-Creole version of the PHQ-9 administered to men who have sex with men (MSM) in the Republic of Haiti. DESIGN: This study uses a cross-sectional design and data are from the Integrated Behavioral and Biological HIV Survey (IBBS) for MSM in Haiti. PARTICIPANTS: Inclusion criteria required that participants be male, ≥ 18 years, report sexual relations with a male partner in the last 12 months, and lived in Haiti during the past 3 months. Respondent Driven Sampling was used for participant recruitment. MAIN MEASURES: A structured questionnaire was verbally administered in Haitian-Creole capturing information on sociodemographics, sexual behaviors, human immunodeficiency virus (HIV) status and depressive symptomatology using the PHQ-9. Psychometric analyses of the translated PHQ-9 assessed unidimensionality, factor structure, reliability, construct validity, and differential item functioning (DIF) across subgroups (age, educational level, sexual orientation and HIV status). KEY RESULTS: In a study population of 1,028 MSM, the Haitian-Creole version of the PHQ-9 is unidimensional, has moderately high internal consistency reliability (α = 0.78), and shows evidence of construct validity where HIV-positive subjects have greater depression (p=0.002). There is no evidence of DIF across age, education, sexual orientation or HIV status. HIVpositive MSM are twice as likely to screen positive for moderately severe and severe depressive symptoms compared to their HIV-negative counterparts. CONCLUSIONS: There is strong evidence for the psychometric adequacy of the translated PHQ-9 screening tool as a measure of depression with MSM in Haiti. Future research is necessary to examine the predictive validity of depression for subsequent health behaviors or clinical outcomes among Haitian MSM.KEYWORDS: Depression; Haiti; HIV/AIDS; International health; men who have sex with men.

The index case of chikungunya virus (CHIKV) in Haiti was reported during early 2014; the vector, the pervasive Aedes aegypti mosquito, promoted rapid spread throughout the country. During December 2014–February 2015, we collected blood samples from 4,438 persons at 154 sites (62 urban, 92 rural) throughout Haiti and measured CHIKV IgG by using a multiplex bead assay. Overall CHIKV seroprevalence was 57.9%; differences between rural (mean 44.9%) and urban (mean 78.4%) areas were pronounced. Logistic modeling identified the urban environment as a strong predictor of CHIKV exposure (adjusted odds ratio 3.34, 95% CI 2.38–4.69), and geographic elevation provided a strong negative correlation. We observed no correlation between age and antibody positivity or titer. Our findings demonstrated through serologic testing the recent and rapid dissemination of the arbovirus throughout the country. These results show the utility of serologic data to conduct epidemiologic studies of quickly spreading mosquitoborne arboviruses.