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1.
Pediatr Infect Dis J ; 42(4): 338-345, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36795582

RESUMO

BACKGROUND: Recent 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. METHODS: We 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. RESULTS: Subprotective 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. CONCLUSIONS: History 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.


Assuntos
Sarampo , Toxoide Tetânico , Tétano , Humanos , Lactente , República Democrática do Congo/epidemiologia , Imunoglobulina G/sangue , Sarampo/epidemiologia , Tétano/epidemiologia , Tétano/prevenção & controle , Pré-Escolar , Anticorpos Antibacterianos/sangue
3.
PLoS One ; 17(5): e0268703, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35587922

RESUMO

BACKGROUND: Tetanus is a potentially fatal disease that is preventable through vaccination. While the Democratic Republic of the Congo (DRC) has continued to improve implementing routine vaccination activities throughout the country, they have struggled to maintain high childhood vaccine coverage. This study aims to examine the seroprevalence of tetanus in children 6 to 59 months to identify areas for intervention and improvement of vaccination coverage. METHODS: In collaboration with the 2013-2014 Demographic and Health Survey, we assessed the seroprevalence of tetanus antibodies among children in the DRC. Dried blood spot samples collected from children 6-59 months of age were processed using a prototype DYNEX Multiplier® chemiluminescent automated immunoassay instrument with a multiplex measles, mumps, rubella, varicella and tetanus assay. Multivariable logistic regression was used to determine factors associated with tetanus vaccination and seroprotection. RESULTS: Overall, 36.1% of children 6-59 months of age reported receiving at least 1 dose of tetanus vaccine while 28.7% reported receiving 3 doses; tetanus seroprotection was 40%. Increasing age in children was associated with decreased tetanus seroprotection, but increased number tetanus vaccinations received. Factors related to increased tetanus seroprotection included number of children in the household, wealth index of the family, urban residence compared to rural, level of maternal education, and province and geography. CONCLUSIONS: Our findings in this nationally representative sample indicate that serology biomarkers may help identify children who are not fully immunized to tetanus more accurately than reported vaccination. While children may be captured for routine immunization activities, as children age, decreasing seroprevalence may indicate additional need to bolster routine vaccination activities and documentation of vaccination in school aged children. Additionally, the study highlights gaps in rural residential areas and vaccination coverage based on maternal education, indicating that policies targeting maternal education and awareness could improve the coverage and seroprevalence of tetanus antibodies in the DRC.


Assuntos
Sarampo , Tétano , Criança , República Democrática do Congo/epidemiologia , Humanos , Lactente , Sarampo/prevenção & controle , Estudos Soroepidemiológicos , Tétano/epidemiologia , Tétano/prevenção & controle , Toxoide Tetânico , Vacinação
4.
BMC Infect Dis ; 22(1): 30, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34986786

RESUMO

BACKGROUND: Vaccination efforts to eradicate polio currently focus on children under 5 years of age, among whom most cases of poliomyelitis still occur. However, in the Democratic Republic of the Congo (DRC), an outbreak of wild poliovirus type 1 occurred in 2010-2011 in which 16% of cases occurred among adults; in a related outbreak in the neighboring Republic of Congo, 75% of cases occurred among the same adult age-group. Given that infected adults may transmit poliovirus, this study was designed to assess adult immunity against polioviruses. METHODS: We assessed poliovirus seroprevalence using dried blood spots from 5,526 adults aged 15-59 years from the 2013-2014 Demographic and Health Survey in the DRC. RESULTS: Among adults in the DRC, 74%, 72%, and 57% were seropositive for neutralizing antibodies for poliovirus types 1, 2, and 3, respectively. For all three serotypes, seroprevalence tended to be higher among older age groups, those living in households with more children, and among women. CONCLUSIONS: Protection against poliovirus is generally low among adults in the DRC, particularly for type 3 poliovirus. The lack of acquired immunity in adults suggests a potentially limited poliovirus circulation over the lifetime of those surveyed (spanning 1954 through 2014) and transmission of vaccine-derived poliovirus in this age group while underscoring the risk of these outbreaks among adults in the DRC.


Assuntos
Poliomielite , Poliovirus , Adulto , Idoso , Criança , Pré-Escolar , Estudos Transversais , República Democrática do Congo/epidemiologia , Surtos de Doenças , Feminino , Humanos , Lactente , Poliomielite/epidemiologia , Poliomielite/prevenção & controle , Vacina Antipólio Oral , Estudos Soroepidemiológicos
5.
J Infect Dis ; 226(4): 608-615, 2022 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-33269402

RESUMO

BACKGROUND: Health care workers (HCW) are more likely to be exposed to Ebola virus (EBOV) during an outbreak compared to people in the general population due to close physical contact with patients and potential exposure to infectious fluids. However, not all will fall ill. Despite evidence of subclinical and paucisymptomatic Ebola virus disease (EVD), prevalence and associated risk factors remain unknown. METHODS: We conducted a serosurvey among HCW in Boende, Tshuapa Province, Democratic Republic of Congo. Human anti-EBOV glycoprotein IgG titers were measured using a commercially available ELISA kit. We assessed associations between anti-EBOV IgG seroreactivity, defined as ≥2.5 units/mL, and risk factors using univariable and multivariable logistic regression. Sensitivity analyses explored a more conservative cutoff, >5 units/mL. RESULTS: Overall, 22.5% of HCWs were seroreactive for EBOV. In multivariable analyses, using any form of personal protective equipment when interacting with a confirmed, probable, or suspect EVD case was negatively associated with seroreactivity (adjusted odds ratio, 0.23; 95% confidence interval, .07-.73). DISCUSSION: Our results suggest high exposure to EBOV among HCWs and provide additional evidence for asymptomatic or minimally symptomatic EVD. Further studies should be conducted to determine the probability of onward transmission and if seroreactivity is associated with immunity.


Assuntos
Ebolavirus , Doença pelo Vírus Ebola , República Democrática do Congo/epidemiologia , Surtos de Doenças , Pessoal de Saúde , Humanos , Imunoglobulina G , Fatores de Risco
6.
PLoS Negl Trop Dis ; 15(8): e0009566, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34383755

RESUMO

BACKGROUND: Ebola virus (EBOV) is a zoonotic filovirus spread through exposure to infected bodily fluids of a human or animal. Though EBOV is capable of causing severe disease, referred to as Ebola Virus Disease (EVD), individuals who have never been diagnosed with confirmed, probable or suspected EVD can have detectable EBOV antigen-specific antibodies in their blood. This study aims to identify risk factors associated with detectable antibody levels in the absence of an EVD diagnosis. METHODOLOGY: Data was collected from September 2015 to August 2017 from 1,366 consenting individuals across four study sites in the DRC (Boende, Kabondo-Dianda, Kikwit, and Yambuku). Seroreactivity was determined to EBOV GP IgG using Zaire Ebola Virus Glycoprotein (EBOV GP antigen) ELISA kits (Alpha Diagnostic International, Inc.) in Kinshasa, DRC; any result above 4.7 units/mL was considered seroreactive. Among the respondents, 113 (8.3%) were considered seroreactive. Several zoonotic exposures were associated with EBOV seroreactivity after controlling for age, sex, healthcare worker status, location, and history of contact with an EVD case, namely: ever having contact with bats, ever having contact with rodents, and ever eating non-human primate meat. Contact with monkeys or non-human primates was not associated with seroreactivity. CONCLUSIONS: This analysis suggests that some zoonotic exposures that have been linked to EVD outbreaks can also be associated with EBOV GP seroreactivity in the absence of diagnosed EVD. Future investigations should seek to clarify the relationships between zoonotic exposures, seroreactivity, asymptomatic infection, and EVD.


Assuntos
Anticorpos Antivirais/sangue , Ebolavirus/imunologia , Glicoproteínas/sangue , Doença pelo Vírus Ebola/epidemiologia , Adulto , Animais , República Democrática do Congo/epidemiologia , Surtos de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Doença pelo Vírus Ebola/sangue , Doença pelo Vírus Ebola/imunologia , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Primatas , Fatores de Risco , Estudos Soroepidemiológicos , Zoonoses
7.
Lancet Infect Dis ; 21(4): e82-e92, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33125913

RESUMO

The spread of Plasmodium falciparum isolates carrying mutations in the kelch13 (Pfkelch13) gene associated with artemisinin resistance (PfART-R) in southeast Asia threatens malaria control and elimination efforts. Emergence of PfART-R in Africa would result in a major public health problem. In this systematic review, we investigate the frequency and spatial distribution of Pfkelch13 mutants in Africa, including mutants linked to PfART-R in southeast Asia. Seven databases were searched (PubMed, Embase, Scopus, African Journal Online, African Index Medicus, Bioline, and Web of Science) for relevant articles about polymorphisms of the Pfkelch13 gene in Africa before January, 2019. Following PRISMA guidelines, 53 studies that sequenced the Pfkelch13 gene of 23 100 sample isolates in 41 sub-Saharan African countries were included. The Pfkelch13 sequence was highly polymorphic (292 alleles, including 255 in the Pfkelch13-propeller domain) but with mutations occurring at very low relative frequencies. Non-synonymous mutations were found in only 626 isolates (2·7%) from west, central, and east Africa. According to WHO, nine different mutations linked to PfART-R in southeast Asia (Phe446Ile, Cys469Tyr, Met476Ile, Arg515Lys, Ser522Cys, Pro553Leu, Val568Gly, Pro574Leu, and Ala675Val) were detected, mainly in east Africa. Several other Pfkelch13 mutations, such as those structurally similar to southeast Asia PfART-R mutations, were also identified, but their relevance for drug resistance is still unknown. This systematic review shows that Africa, thought to not have established PfART-R, reported resistance-related mutants in the past 5 years. Surveillance using PfART-R molecular markers can provide valuable decision-making information to sustain the effectiveness of artemisinin in Africa.


Assuntos
Artemisininas/farmacologia , Resistência a Medicamentos/genética , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , África/epidemiologia , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , Genes de Protozoários/genética , Humanos , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Mutação , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/isolamento & purificação , Polimorfismo de Nucleotídeo Único
8.
Am J Trop Med Hyg ; 104(2): 604-611, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-33289470

RESUMO

Recent enhanced monkeypox (MPX) surveillance in the Democratic Republic of Congo, where MPX is endemic, has uncovered multiple cases of MPX and varicella zoster virus (VZV) coinfections. The purpose of this study was to verify if coinfections occur and to characterize the clinical nature of these cases. Clinical, epidemiological, and laboratory results were used to investigate MPX/VZV coinfections. A coinfection was defined as a patient with at least one Orthopoxvirus/MPX-positive sample and at least one VZV-positive sample within the same disease event. Between September 2009 and April 2014, 134 of the 1,107 (12.1%) suspected MPX cases were confirmed as MPX/VZV coinfections. Coinfections were more likely to report symptoms than VZV-alone cases and less likely than MPX-alone cases. Significantly higher lesion counts were observed for coinfection cases than for VZV-alone but less than MPX-alone cases. Discernible differences in symptom and rash severity were detected for coinfection cases compared with those with MPX or VZV alone. Findings indicate infection with both MPX and VZV could modulate infection severity. Collection of multiple lesion samples allows for the opportunity to detect coinfections. As this program continues, it will be important to continue these procedures to assess variations in the proportion of coinfected cases over time.


Assuntos
Coinfecção/epidemiologia , Coinfecção/virologia , Herpes Zoster/epidemiologia , Herpesvirus Humano 3/genética , Monkeypox virus/genética , Mpox/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , República Democrática do Congo/epidemiologia , Monitoramento Epidemiológico , Feminino , Herpesvirus Humano 3/isolamento & purificação , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Monkeypox virus/isolamento & purificação , Adulto Jovem
9.
J Infect Dis ; 222(12): 2021-2029, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-32255180

RESUMO

BACKGROUND: Our understanding of the different effects of targeted versus nontargeted violence on Ebola virus (EBOV) transmission in Democratic Republic of the Congo (DRC) is limited. METHODS: We used time-series data of case counts to compare individuals in Ebola-affected health zones in DRC, April 2018-August 2019. Exposure was number of violent events per health zone, categorized into Ebola-targeted or Ebola-untargeted, and into civilian-induced, (para)military/political, or protests. Outcome was estimated daily reproduction number (Rt) by health zone. We fit linear time-series regression to model the relationship. RESULTS: Average Rt was 1.06 (95% confidence interval [CI], 1.02-1.11). A mean of 2.92 violent events resulted in cumulative absolute increase in Rt of 0.10 (95% CI, .05-.15). More violent events increased EBOV transmission (P = .03). Considering violent events in the 95th percentile over a 21-day interval and its relative impact on Rt, Ebola-targeted events corresponded to Rt of 1.52 (95% CI, 1.30-1.74), while civilian-induced events corresponded to Rt of 1.43 (95% CI, 1.21-1.35). Untargeted events corresponded to Rt of 1.18 (95% CI, 1.02-1.35); among these, militia/political or ville morte events increased transmission. CONCLUSIONS: Ebola-targeted violence, primarily driven by civilian-induced events, had the largest impact on EBOV transmission.


Assuntos
Conflitos Armados/classificação , Distúrbios Civis/classificação , Surtos de Doenças , Mapeamento Geográfico , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/transmissão , República Democrática do Congo/epidemiologia , Ebolavirus , Humanos
10.
Vaccine ; 38(9): 2258-2265, 2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-32057333

RESUMO

BACKGROUND: Measles is endemic in the Democratic Republic of the Congo (DRC), and 89-94% herd immunity is required to halt its transmission. Much of the World Health Organization African Region, including the DRC, has vaccination coverage below the 95% level required to eliminate measles, heightening concern of inadequate measles immunity. METHODS: We assessed 6706 children aged 6-59 months 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 was completed using maternal recall and measles immunoglobulin G serostatus obtained from a multiplex chemiluminescent automated immunoassay dried blood spot analysis. A logistic regression model was used to identify associations of covariates with measles and seroprotection, and vaccine effectiveness (VE) was calculated. RESULTS: Out of our sample, 64% of children were seroprotected. Measles vaccination was associated with protection against measles (OR: 0.15, 95% CI: 0.03, 0.81) when administered to children 12 months of age or older. Vaccination was predictive of seroprotection at all ages. VE was highest (88%) among children 12-24 months of age. CONCLUSION: Our results demonstrated lower than expected seroprotection against measles among vaccinated children. Understanding the factors that affect host immunity to measles will aid in developing more efficient and effective immunization programs in DRC.


Assuntos
Anticorpos Antivirais/sangue , Vacina contra Sarampo/administração & dosagem , Sarampo , Estudos Soroepidemiológicos , Pré-Escolar , República Democrática do Congo/epidemiologia , Feminino , Humanos , Programas de Imunização , Imunoglobulina G/sangue , Lactente , Masculino , Sarampo/epidemiologia , Sarampo/prevenção & controle , Cobertura Vacinal/estatística & dados numéricos
11.
Emerg Microbes Infect ; 9(1): 124-128, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31913767

RESUMO

A serological survey of 2,430 archived serum samples collected between 1997 and 2012 was conducted to retrospectively determine the prevalence of Marburg virus in five African countries. Serum samples were screened for neutralizing antibodies in a pseudotype micro-neutralization assay and confirmed by enzyme-linked immunosorbent assay (ELISA). Surprisingly, a seroprevalence for Marburg virus of 7.5 and 6.3% was found in Cameroon and Ghana, respectively, suggesting the circulation of filoviruses or related viruses outside of known endemic areas that remain undetected by current surveillance efforts. However, due to the lack of validated assays and appropriate positive controls, these results must be considered preliminary.


Assuntos
Anticorpos Antivirais/sangue , Filoviridae/imunologia , Doença do Vírus de Marburg/sangue , Doença do Vírus de Marburg/epidemiologia , Marburgvirus/imunologia , Animais , Camarões/epidemiologia , Ensaio de Imunoadsorção Enzimática , Filoviridae/genética , Infecções por Filoviridae/sangue , Infecções por Filoviridae/epidemiologia , Infecções por Filoviridae/virologia , Gana/epidemiologia , Humanos , Doença do Vírus de Marburg/virologia , Marburgvirus/genética , Estudos Retrospectivos , Estudos Soroepidemiológicos
12.
Int J STD AIDS ; 31(3): 221-229, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31996095
13.
Epidemics ; 28: 100354, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31395373

RESUMO

As of June 16, 2019, an Ebola virus disease (EVD) outbreak has led to 2136 reported cases in the northeastern region of the Democratic Republic of the Congo (DRC). As this outbreak continues to threaten the lives and livelihoods of people already suffering from civil strife and armed conflict, relatively simple mathematical models and their short-term predictions have the potential to inform Ebola response efforts in real time. We applied recently developed non-parametrically estimated Hawkes point processes to model the expected cumulative case count using daily case counts from May 3, 2018, to June 16, 2019, initially reported by the Ministry of Health of DRC and later confirmed in World Health Organization situation reports. We generated probabilistic estimates of the ongoing EVD outbreak in DRC extending both before and after June 16, 2019, and evaluated their accuracy by comparing forecasted vs. actual outbreak sizes, out-of-sample log-likelihood scores and the error per day in the median forecast. The median estimated outbreak sizes for the prospective thee-, six-, and nine-week projections made using data up to June 16, 2019, were, respectively, 2317 (95% PI: 2222, 2464); 2440 (95% PI: 2250, 2790); and 2544 (95% PI: 2273, 3205). The nine-week projection experienced some degradation with a daily error in the median forecast of 6.73 cases, while the six- and three-week projections were more reliable, with corresponding errors of 4.96 and 4.85 cases per day, respectively. Our findings suggest the Hawkes point process may serve as an easily-applied statistical model to predict EVD outbreak trajectories in near real-time to better inform decision-making and resource allocation during Ebola response efforts.


Assuntos
Surtos de Doenças , Doença pelo Vírus Ebola/epidemiologia , Coleta de Dados , Tomada de Decisões , República Democrática do Congo/epidemiologia , Ebolavirus , Humanos , Modelos Estatísticos , Modelos Teóricos , Estudos Prospectivos , Tempo
14.
Am J Trop Med Hyg ; 101(4): 828-836, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31392943

RESUMO

Schistosomiasis afflicts an estimated 10 million pregnant women in Africa annually. With mounting evidence of adverse impacts to reproductive health resulting from urogenital schistosomiasis, including increased transmission of HIV, further research on prenatal disease epidemiology is warranted, with implications for maternal and fetal health. Between October 2016 and March 2017, we conducted a cross-sectional study examining the prevalence of urogenital schistosomiasis and its association with sexually transmitted infections (STIs) other than HIV among pregnant women visiting antenatal clinics in Kisantu health zone, Democratic Republic of Congo. An extensive sociodemographic and clinical survey was administered to consenting participants, with urine samples and vaginal swabs collected to deduce active schistosomiasis and STIs, respectively. In total, 17.4% of expectant mothers were infected with Schistosoma haematobium, 3.1% with Chlamydia trachomatis (CT), 1.4% with Neisseria gonorrhoeae (NG), and 14.6% with Trichomonas vaginalis (TV). Women infected with urogenital schistosomiasis were at significantly increased odds of harboring a CT, NG, or TV infection (adjusted odds ratio = 3.0, 95% CI: 1.5, 6.0), but reports of clinical symptoms were low, ranging from 17.2% of schistosomiasis to 30.8% of TV cases. Laboratory confirmation of schistosomiasis and STIs provided objective evidence of disease in a cohort with low symptomology where syndromic management may not suffice. Shedding light on local risk factors and associated coinfections of urogenital schistosomiasis can identify unique intervention opportunities for prenatal care in trematode-endemic regions and aid in reducing adverse pregnancy outcomes.


Assuntos
Coinfecção/epidemiologia , Doenças Endêmicas , Doenças Urogenitais Femininas/epidemiologia , Complicações Infecciosas na Gravidez/epidemiologia , Esquistossomose Urinária/epidemiologia , Infecções Sexualmente Transmissíveis/epidemiologia , Adulto , Estudos Transversais , República Democrática do Congo/epidemiologia , Feminino , Humanos , Gravidez , Esquistossomose Urinária/etiologia
15.
Epidemics ; 28: 100353, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31378584

RESUMO

INTRODUCTION: As of April 2019, the current Ebola virus disease (EVD) outbreak in the Democratic Republic of the Congo (DRC) is occurring in a longstanding conflict zone and has become the second largest EVD outbreak in history. It is suspected that after violent events occur, EVD transmission will increase; however, empirical studies to understand the impact of violence on transmission are lacking. Here, we use spatial and temporal trends of EVD case counts to compare transmission rates between health zones that have versus have not experienced recent violent events during the outbreak. METHODS: We collected daily EVD case counts from DRC Ministry of Health. A time-varying indicator of recent violence in each health zone was derived from events documented in the WHO situation reports. We used the Wallinga-Teunis technique to estimate the reproduction number R for each case by day per zone in the 2018-2019 outbreak. We fit an exponentially decaying curve to estimates of R overall and by health zone, for comparison to past outbreaks. RESULTS: As of 16 April 2019, the mean overall R for the entire outbreak was 1.11. We found evidence of an increase in the estimated transmission rates in health zones with recently reported violent events versus those without (p = 0.008). The average R was estimated as between 0.61 and 0.86 in regions not affected by recent violent events, and between 1.01 and 1.07 in zones affected by violent events within the last 21 days, leading to an increase in R between 0.17 and 0.53. Within zones with recent violent events, the mean estimated quenching rate was lower than for all past outbreaks except the 2013-2016 West African outbreak. CONCLUSION: The difference in the estimated transmission rates between zones affected by recent violent events suggests that violent events are contributing to increased transmission and the ongoing nature of this outbreak.


Assuntos
Surtos de Doenças , Doença pelo Vírus Ebola/epidemiologia , Violência , República Democrática do Congo/epidemiologia , Humanos , Tempo
16.
PLoS Negl Trop Dis ; 13(8): e0007512, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31381606

RESUMO

BACKGROUND: As of February 25, 2019, 875 cases of Ebola virus disease (EVD) were reported in North Kivu and Ituri Provinces, Democratic Republic of Congo. Since the beginning of October 2018, the outbreak has largely shifted into regions in which active armed conflict has occurred, and in which EVD cases and their contacts have been difficult for health workers to reach. We used available data on the current outbreak, with case-count time series from prior outbreaks, to project the short-term and long-term course of the outbreak. METHODS: For short- and long-term projections, we modeled Ebola virus transmission using a stochastic branching process that assumes gradually quenching transmission rates estimated from past EVD outbreaks, with outbreak trajectories conditioned on agreement with the course of the current outbreak, and with multiple levels of vaccination coverage. We used two regression models to estimate similar projection periods. Short- and long-term projections were estimated using negative binomial autoregression and Theil-Sen regression, respectively. We also used Gott's rule to estimate a baseline minimum-information projection. We then constructed an ensemble of forecasts to be compared and recorded for future evaluation against final outcomes. From August 20, 2018 to February 25, 2019, short-term model projections were validated against known case counts. RESULTS: During validation of short-term projections, from one week to four weeks, we found models consistently scored higher on shorter-term forecasts. Based on case counts as of February 25, the stochastic model projected a median case count of 933 cases by February 18 (95% prediction interval: 872-1054) and 955 cases by March 4 (95% prediction interval: 874-1105), while the auto-regression model projects median case counts of 889 (95% prediction interval: 876-933) and 898 (95% prediction interval: 877-983) cases for those dates, respectively. Projected median final counts range from 953 to 1,749. Although the outbreak is already larger than all past Ebola outbreaks other than the 2013-2016 outbreak of over 26,000 cases, our models do not project that it is likely to grow to that scale. The stochastic model estimates that vaccination coverage in this outbreak is lower than reported in its trial setting in Sierra Leone. CONCLUSIONS: Our projections are concentrated in a range up to about 300 cases beyond those already reported. While a catastrophic outbreak is not projected, it is not ruled out, and prevention and vigilance are warranted. Prospective validation of our models in real time allowed us to generate more accurate short-term forecasts, and this process may prove useful for future real-time short-term forecasting. We estimate that transmission rates are higher than would be seen under target levels of 62% coverage due to contact tracing and vaccination, and this model estimate may offer a surrogate indicator for the outbreak response challenges.


Assuntos
Ebolavirus/patogenicidade , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/prevenção & controle , Doença pelo Vírus Ebola/transmissão , Cobertura Vacinal , República Democrática do Congo/epidemiologia , Surtos de Doenças/prevenção & controle , Pessoal de Saúde , Humanos , Modelos Teóricos , Estudos Prospectivos , Análise de Regressão
17.
mSphere ; 4(4)2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31413172

RESUMO

Here we describe baseline validation studies and field performance of a research-use-only chemiluminescent multiplex serology panel for measles, mumps, rubella, and varicella-zoster virus used with dried blood spots in support of the 2013-2014 Democratic Republic of the Congo Demographic and Health Survey. Characterization of the panel using U.S. FDA-cleared commercial kits shows good concordance for measles, mumps, rubella, and varicella-zoster with average sensitivity across assays of 94.9% and an average specificity of 91.4%. As expected, performance versus available standards validated for plaque-reduction assays does not provide a 1:1 correspondence with international units and yet demonstrates excellent linearity (average Hill's slope = 1.02) and ∼4 logs of dynamic range. In addition, for the four assays, the multiplexed format allowed for inclusion of three positive and two negative controls for each sample. A prototype Dynex Multiplier chemiluminescent automated immunoassay instrument with a charge-coupled device camera provided a rugged and robust processing and data acquisition platform. Performance of a multiplex instrument for serological testing in a substantially resource-limited environment shows excellent reproducibility, minimal cross-reactivity, and a clear discrimination between specific assays and should be considered a viable option for future serosurveys.IMPORTANCE The critical evaluation of immunization programs is key to identifying areas of suboptimal vaccination coverage, monitoring activities, and aiding development of public health policy. For evaluation of vaccine effectiveness, direct antibody binding assay methods, including enzyme immunoassay, enzyme-linked fluorescence assays, and indirect immunofluorescence assay, are most commonly used for detection of IgG antibodies. However, despite their well-demonstrated, reliable performance, they can be labor-intensive and time-consuming and require separate assays for each individual marker. This necessitates increased sample volumes, processing time, and personnel, which may limit assessment to a few key targets in resource-limited settings, that is, low- and middle-income locations where funding for public health or general infrastructure that directly impacts public health is restricted, limiting access to equipment, infrastructure, and trained personnel. One solution is a multiplexed immunoassay, which allows for the detection of multiple analytes in a single reaction for increased efficiency and rapid surveillance of infectious diseases in limited-resource settings. Thus, the scope of the project precluded a full validation, and here we present abbreviated validation studies demonstrating adequate sensitivity, specificity, and reproducibility.


Assuntos
Varicela/diagnóstico , Teste em Amostras de Sangue Seco/normas , Imunoensaio/normas , Medições Luminescentes/normas , Sarampo/diagnóstico , Caxumba/diagnóstico , Rubéola (Sarampo Alemão)/diagnóstico , Anticorpos Antivirais/sangue , Automação Laboratorial/normas , República Democrática do Congo , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
PLoS One ; 14(5): e0217426, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31125375

RESUMO

Despite increased vaccination rates, the burden, morbidity and mortality associated with vaccine preventable diseases remains high. In the Democratic Republic of the Congo (DRC), potentially unreliable data and geographically varied program provision call for a better understanding of vaccination coverage and its changes over time at the country and province level. To assess changes in the proportion of children who were fully vaccinated over time in the DRC, vaccination histories for children 12-59 months of age were obtained from both the 2007 and 2013-2014 Demographic and Health Surveys (DHS). Changes were assessed, both at the country- and province-levels, to identify potential geographic variations. Vaccination coverage improved 70% between the DHS waves: 26% compared to 44% of 12-59 month-old children met full vaccination criteria in 2007 and 2013-2014, respectively (n2007 = 3032 and n2013-14 = 6619). Similarly, there was an overall trend across both DHS waves where as year of birth increased, so did vaccination coverage. There was geographic variation in immunization changes with most central and eastern provinces increasing in coverage and most northern, western and southern provinces having decreased vaccination coverage at the second time point. Using nationally representative data, we identified significant changes over time in vaccination coverage which may help to inform future policy, interventions and research to improve vaccination rates among children in the DRC. This study is the first of its kind for the population of DRC and provides an important initial step towards better understanding trends in vaccination coverage over time.


Assuntos
Cobertura Vacinal , Pré-Escolar , Estudos Transversais , República Democrática do Congo/epidemiologia , Humanos , Programas de Imunização/estatística & dados numéricos , Lactente , Recém-Nascido , Vacinação/estatística & dados numéricos , Cobertura Vacinal/estatística & dados numéricos
19.
PLoS One ; 14(3): e0213190, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30845236

RESUMO

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.


Assuntos
Doença pelo Vírus Ebola/epidemiologia , Modelos Teóricos , Vacinação , República Democrática do Congo/epidemiologia , Surtos de Doenças , Doença pelo Vírus Ebola/prevenção & controle , Humanos
20.
J Infect Dis ; 219(4): 517-525, 2019 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-30239838

RESUMO

Healthcare settings have played a major role in propagation of Ebola virus (EBOV) outbreaks. Healthcare workers (HCWs) have elevated risk of contact with EBOV-infected patients, particularly if safety precautions are not rigorously practiced. We conducted a serosurvey to determine seroprevalence against multiple EBOV antigens among HCWs of Boende Health Zone, Democratic Republic of the Congo, the site of a 2014 EBOV outbreak. Interviews and specimens were collected from 565 consenting HCWs. Overall, 234 (41.4%) of enrolled HCWs were reactive to at least 1 EBOV protein: 159 (28.1%) were seroreactive for anti-glycoprotein immunoglobulin G (IgG), 89 (15.8%) were seroreactive for anti-nucleoprotein IgG, and 54 (9.5%) were VP40 positive. Additionally, sera from 16 (2.8%) HCWs demonstrated neutralization capacity. These data demonstrate that a significant proportion of HCWs have the ability to neutralize virus, despite never having developed Ebola virus disease symptoms, highlighting an important and poorly documented aspect of EBOV infection and progression.


Assuntos
Anticorpos Antivirais/sangue , Ebolavirus/imunologia , Pessoal de Saúde , Estudos Soroepidemiológicos , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/sangue , República Democrática do Congo , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Adulto Jovem
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