Human immunodeficiency virus type 1 (HIV-1) proviral DNA load in purified CD4+ cells by LightCycler(® )Real-time PCR

BACKGROUND: The human immunodeficiency virus type 1 (HIV-1) proviral DNA persists in infected cells, even after prolonged successful HAART. In the present study, a relative quantification assay of HIV-1 proviral DNA by LightCycler(® )real-time PCR based on SYBR Green I detection was developed in comparison to the number of purified CD4+ cells as estimated by the quantification of the β-globin gene. METHODS: The ability of the designed gag primers to quantify HIV-1 Group M and the PCR efficiency were assessed on HIV-1 reference isolate subtypes A, B, C and D. The 8E5 cell line containing a single defective copy of HIV-1 proviral DNA was used as a standard for both the HIV-1 target gene and the β-globin reference gene. The assay was applied on thirty consecutive patient samples received for RNA viral load determinations and on retrospective samples from fifteen patients undergoing 2 years of structured treatment interruption (STI). RESULTS: The lower limit of quantification was 50 HIV-1 DNA proviral copies per CD4+ cell sample. The dynamic range was from 50 to 10(6 )HIV-1 DNA copies per CD4+ cell sample with intra- and inter-assay coefficients of variability ranging from 3.1% to 37.1%. The β-globin reference gene was quantified down to a limit of 1.5 pg of DNA/μl (approximately 5 cells) with intra- and interassay coefficients of variability ranging from 1.8% to 21%. DNA proviral load varies widely among HIV-1 infected patients. Proviral load and plasma viral load rebound were high in STI patients who took longer to achieve an undetectable plasma viral load under therapy. A statistically significant correlation was observed between DNA proviral load and RNA steady state viral load in STI patients (p-value = 0,012). CONCLUSION: We have developed a fast, sensitive and specific relative quantification assay of HIV-1 proviral DNA in purified CD4+ cells. The assay enables the monitoring of HIV-1 proviral load, which may be useful to monitor therapy efficacy especially in patients with undetectable plasma RNA viral load, and allows the exploration of viral reservoirs

Predictors of measles vaccination coverage among children 6-59 months of age in the Democratic Republic of the Congo.

BackgroundMeasles is a significant contributor to child mortality in the Democratic Republic of the Congo (DRC), despite routine immunization programs and supplementary immunization activities (SIA). Further, national immunization coverage levels may hide disparities among certain groups of children, making effective measles control even more challenging. This study describes measles vaccination coverage and reporting methods and identifies predictors of vaccination among children participating in the 2013-2014 DRC Demographic and Health Survey (DHS).MethodsWe examined vaccination coverage of 6947 children aged 6-59 months. A multivariate logistic regression model was used to identify predictors of vaccination among children reporting vaccination via dated card in order to identify least reached children. We also assessed spatial distribution of vaccination report type by rural versus urban residence.ResultsUrban children with educated mothers were more likely to be vaccinated (OR = 4.1, 95% CI: 1.6, 10.7) versus children of mothers with no education, as were children in wealthier rural families (OR = 2.9, 95% CI: 1.9, 4.4). At the provincial level, urban areas more frequently reported vaccination via dated card than rural areas.ConclusionsResults indicate that, while the overall coverage level of 70% is too low, socioeconomic and geographic disparities also exist which could make some children even less likely to be vaccinated. Dated records of measles vaccination must be increased, and groups of children with the greatest need should be targeted. As access to routine vaccination services is limited in DRC, identifying and targeting under-reached children should be a strategic means of increasing country-wide effective measles control

Association of Previous Measles Infection With Markers of Acute Infectious Disease Among 9- to 59-Month-Old Children in the Democratic Republic of the Congo.

BackgroundTransient immunosuppression and increased susceptibility to other infections after measles infection is well known, but recent studies have suggested the occurrence of an "immune amnesia" that could have long-term immunosuppressive effects.MethodsWe examined the association between past measles infection and acute episodes of fever, cough, and diarrhea among 2350 children aged 9 to 59 months whose mothers were selected for interview in the 2013-2014 Democratic Republic of the Congo (DRC) Demographic and Health Survey (DHS). Classification of children who had had measles was completed using maternal recall and measles immunoglobulin G serostatus obtained via dried-blood-spot analysis with a multiplex immunoassay. The association with time since measles infection and fever, cough, and diarrhea outcomes was also examined.ResultsThe odds of fever in the previous 2 weeks were 1.80 (95% confidence interval [CI], 1.25-2.60) among children for whom measles was reported compared to children with no history of measles. Measles vaccination demonstrated a protective association against selected clinical markers of acute infectious diseases.ConclusionOur results suggest that measles might have a long-term effect on selected clinical markers of acute infectious diseases among children aged 9 to 59 months in the DRC. These findings support the immune-amnesia hypothesis suggested by others and underscore the need for continued evaluation and improvement of the DRC's measles vaccination program

Neurological, Cognitive, and Psychological Findings Among Survivors of Ebola Virus Disease From the 1995 Ebola Outbreak in Kikwit, Democratic Republic of Congo: A Cross-sectional Study.

BackgroundClinical sequelae of Ebola virus disease (EVD) have not been described more than 3 years postoutbreak. We examined survivors and close contacts from the 1995 Ebola outbreak in Kikwit, Democratic Republic of Congo (DRC), and determined prevalence of abnormal neurological, cognitive, and psychological findings and their association with EVD survivorship.MethodsFrom August to September 2017, we conducted a cross-sectional study in Kikwit, DRC. Over 2 decades after the EVD outbreak, we recruited EVD survivors and close contacts from the outbreak to undergo physical examination and culturally adapted versions of the Folstein mini-mental status exam (MMSE) and Goldberg anxiety and depression scale (GADS). We estimated the strength of relationships between EVD survivorship and health outcomes using linear regression models by comparing survivors versus close contacts, adjusting for age, sex, educational level, marital status, and healthcare worker status.ResultsWe enrolled 20 EVD survivors and 187 close contacts. Among the 20 EVD survivors, 4 (20%) reported at least 1 abnormal neurological symptom, and 3 (15%) had an abnormal neurological examination. Among the 187 close contacts, 14 (11%) reported at least 1 abnormal neurologic symptom, and 9 (5%) had an abnormal neurological examination. EVD survivors had lower mean MMSE and higher mean GADS scores as compared to close contacts (MMSE: adjusted coefficient: -1.85; 95% confidence interval [CI]: -3.63, -0.07; GADS: adjusted coefficient: 3.91; 95% CI: 1.76, 6.04).ConclusionsEVD survivors can have lower cognitive scores and more symptoms of depression and anxiety than close contacts more than 2 decades after Ebola virus outbreaks

Projections of Ebola outbreak size and duration with and without vaccine use in Équateur, Democratic Republic of Congo, as of May 27, 2018.

As of May 27, 2018, 6 suspected, 13 probable and 35 confirmed cases of Ebola virus disease (EVD) had been reported in Équateur Province, Democratic Republic of Congo. We used reported case counts and time series from prior outbreaks to estimate the total outbreak size and duration with and without vaccine use. We modeled Ebola virus transmission using a stochastic branching process model that included reproduction numbers from past Ebola outbreaks and a particle filtering method to generate a probabilistic projection of the outbreak size and duration conditioned on its reported trajectory to date; modeled using high (62%), low (44%), and zero (0%) estimates of vaccination coverage (after deployment). Additionally, we used the time series for 18 prior Ebola outbreaks from 1976 to 2016 to parameterize the Thiel-Sen regression model predicting the outbreak size from the number of observed cases from April 4 to May 27. We used these techniques on probable and confirmed case counts with and without inclusion of suspected cases. Probabilistic projections were scored against the actual outbreak size of 54 EVD cases, using a log-likelihood score. With the stochastic model, using high, low, and zero estimates of vaccination coverage, the median outbreak sizes for probable and confirmed cases were 82 cases (95% prediction interval [PI]: 55, 156), 104 cases (95% PI: 58, 271), and 213 cases (95% PI: 64, 1450), respectively. With the Thiel-Sen regression model, the median outbreak size was estimated to be 65.0 probable and confirmed cases (95% PI: 48.8, 119.7). Among our three mathematical models, the stochastic model with suspected cases and high vaccine coverage predicted total outbreak sizes closest to the true outcome. Relatively simple mathematical models updated in real time may inform outbreak response teams with projections of total outbreak size and duration

Reported History of Measles and Long-term Impact on Tetanus Antibody Detected in Children 9–59 Months of Age and Receiving 3 Doses of Tetanus Vaccine in the Democratic Republic of the Congo

BackgroundRecent studies suggest measles-induced immune amnesia could have long-term immunosuppressive effects via preferential depletion of memory CD150+ lymphocytes, and associations with a 2-3 year period of increased mortality and morbidity from infectious diseases other than measles has been shown in children from wealthy and low-income countries. To further examine the associations previous measles virus infection may have on immunologic memory among children in the Democratic Republic of the Congo (DRC), we assessed tetanus antibody levels among fully vaccinated children, with and without a history of measles.MethodsWe assessed 711 children 9-59 months of age whose mothers were selected for interview in the 2013-2014 DRC Demographic and Health Survey. History of measles was obtained by maternal report and classification of children who had measles in the past was completed using maternal recall and measles IgG serostatus obtained from a multiplex chemiluminescent automated immunoassay dried blood spot analysis. Tetanus IgG antibody serostatus was similarly obtained. A logistic regression model was used to identify association of measles and other predictors with subprotective tetanus IgG antibody.ResultsSubprotective geometric mean concentration tetanus IgG antibody values were seen among fully vaccinated children 9-59 months of age, who had a history of measles. Controlling for potential confounding variables, children classified as measles cases were less likely to have seroprotective tetanus toxoid antibody (odds ratio: 0.21; 95% confidence interval: 0.08-0.55) compared with children who had not had measles.ConclusionsHistory of measles was associated with subprotective tetanus antibody among this sample of children in the DRC who were 9-59 months of age and fully vaccinated against tetanus

Rapid Confirmation of the Zaire Ebola Virus in the Outbreak of the Equateur Province in the Democratic Republic of Congo: Implications for Public Health Interventions.

Ten days after the declaration of the Ebola outbreak in the Democratic Republic of Congo, rapid identification of the species Zaire Ebola virus using partial gene amplification and nanopore sequencing backed up the use of the recombinant vesicular stomatitis virus-Zaire Ebola virus vaccine in the recommended ring vaccination strategy

Poliovirus-Neutralizing Antibody Seroprevalence and Vaccine Habits in a Vaccine-Derived Poliovirus Outbreak Region in the Democratic Republic of Congo in 2018: The Impact on the Global Eradication Initiative

Despite the successes in wild-type polio eradication, poor vaccine coverage in the DRC has led to the occurrence of circulating vaccine-derived poliovirus outbreaks. This cross-sectional population-based survey provides an update to previous poliovirus-neutralizing antibody seroprevalence studies in the DRC and quantifies risk factors for under-immunization and parental knowledge that guide vaccine decision making. Among the 964 children between 6 and 35 months in our survey, 43.8% (95% CI: 40.6-47.0%), 41.1% (38.0-44.2%), and 38.0% (34.9-41.0%) had protective neutralizing titers to polio types 1, 2, and 3, respectively. We found that 60.7% of parents reported knowing about polio, yet 25.6% reported knowing how it spreads. Our data supported the conclusion that polio outreach efforts were successfully connecting with communities-79.4% of participants had someone come to their home with information about polio, and 88.5% had heard of a polio vaccination campaign. Additionally, the odds of seroreactivity to only serotype 2 were far greater in health zones that had a history of supplementary immunization activities (SIAs) compared to health zones that did not. While SIAs may be reaching under-vaccinated communities as a whole, these results are a continuation of the downward trend of seroprevalence rates in this region

Leptospirosis as a cause of fever associated with jaundice in the Democratic Republic of the Congo.

BACKGROUND: Fever with jaundice is a common symptom of some infectious diseases. In public health surveillance within the Democratic Republic of the Congo (DRC), yellow fever is the only recognized cause of fever with jaundice. However, only 5% of the surveillance cases are positive for yellow fever and thus indicate the involvement of other pathogens. Leptospira spp. are the causative agents of leptospirosis, a widespread bacterial zoonosis, a known cause of fever with jaundice. This study aimed to determine the seropositivity of anti-Leptospira antibodies among suspected yellow fever cases and map the geographical distribution of possible leptospirosis in the DRC. METHODS: We conducted a retrospective study using 1,300 samples from yellow fever surveillance in the DRC from January 2017 to December 2018. Serum samples were screened for the presence of IgM against Leptospira spp. by a whole cell-based IgM ELISA (Patoc-IgM ELISA) at the Institut National de Recherche Biomedicale in Kinshasa (INRB) according to World Health Organization (WHO) guidance. Exploratory univariable and multivariable logistic regression analyses were undertaken to assess associations between socio-demographic factors and the presence of Leptospira IgM. RESULTS: Of the 1,300 serum samples screened, 88 (7%) showed evidence of IgM against Leptospira spp. Most positive cases (34%) were young adult males in the 20-29-year group. There were statistically significant associations between having Leptospira IgM antibodies, age, sex, and living area. Observed positive cases were mostly located in urban settings, and the majority lived in the province of Kinshasa. There was a statistically significant association between seasonality and IgM Leptospira spp. positivity amongst those living in Kinshasa, where most of the positive cases occurred during the rainy season. CONCLUSIONS: This study showed that leptospirosis is likely an overlooked cause of unexplained cases of fever with jaundice in the DRC and highlights the need to consider leptospirosis in the differential diagnosis of fever with jaundice, particularly in young adult males. Further studies are needed to identify animal reservoirs, associated risk factors, and the burden of human leptospirosis in the DRC