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1.
PLoS Pathog ; 18(12): e1010996, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36520713

RESUMEN

Yersinia pestis, the bacterial agent of plague, is enzootic in many parts of the world within wild rodent populations and is transmitted by different flea vectors. The ecology of plague is complex, with rodent hosts exhibiting varying susceptibilities to overt disease and their fleas exhibiting varying levels of vector competence. A long-standing question in plague ecology concerns the conditions that lead to occasional epizootics among susceptible rodents. Many factors are involved, but a major one is the transmission efficiency of the flea vector. In this study, using Oropsylla montana (a ground squirrel flea that is a major plague vector in the western United States), we comparatively quantified the efficiency of the two basic modes of flea-borne transmission. Transmission efficiency by the early-phase mechanism was strongly affected by the host blood source. Subsequent biofilm-dependent transmission by blocked fleas was less influenced by host blood and was more efficient. Mathematical modeling predicted that early-phase transmission could drive an epizootic only among highly susceptible rodents with certain blood characteristics, but that transmission by blocked O. montana could do so in more resistant hosts irrespective of their blood characteristics. The models further suggested that for most wild rodents, exposure to sublethal doses of Y. pestis transmitted during the early phase may restrain rapid epizootic spread by increasing the number of immune, resistant individuals in the population.


Asunto(s)
Peste , Siphonaptera , Yersinia pestis , Animales , Insectos Vectores/microbiología , Siphonaptera/microbiología , Roedores
2.
MMWR Morb Mortal Wkly Rep ; 73(18): 417-419, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38722800

RESUMEN

Malaria is a severe and potentially fatal mosquitoborne disease caused by infection with Plasmodium spp. parasites. Although malaria is no longer endemic in the United States, imported infections are reported annually; the primary risk group has been U.S. residents traveling to areas where malaria is endemic (1). In 2023, sporadic locally acquired mosquito-transmitted malaria cases were reported in several U.S. states (2,3). This report describes increases in imported malaria cases in 2023 compared with 2022 in three public health jurisdictions along the U.S. southern border.


Asunto(s)
Enfermedades Transmisibles Importadas , Malaria , Humanos , Malaria/epidemiología , Enfermedades Transmisibles Importadas/epidemiología , Estados Unidos/epidemiología , Viaje
3.
Emerg Infect Dis ; 29(6): 1143-1153, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37209670

RESUMEN

Achieving malaria elimination requires considering both Plasmodium falciparum and non-P. falciparum infections. We determined prevalence and geographic distribution of 4 Plasmodium spp. by performing PCR on dried blood spots collected within 8 regions of Tanzania during 2017. Among 3,456 schoolchildren, 22% had P. falciparum, 24% had P. ovale spp., 4% had P. malariae, and 0.3% had P. vivax infections. Most (91%) schoolchildren with P. ovale infections had low parasite densities; 64% of P. ovale infections were single-species infections, and 35% of those were detected in low malaria endemic regions. P. malariae infections were predominantly (73%) co-infections with P. falciparum. P. vivax was detected mostly in northern and eastern regions. Co-infections with >1 non-P. falciparum species occurred in 43% of P. falciparum infections. A high prevalence of P. ovale infections exists among schoolchildren in Tanzania, underscoring the need for detection and treatment strategies that target non-P. falciparum species.


Asunto(s)
Coinfección , Malaria Falciparum , Malaria Vivax , Malaria , Humanos , Niño , Plasmodium falciparum/genética , Prevalencia , Tanzanía/epidemiología , Coinfección/epidemiología , Plasmodium malariae , Malaria/epidemiología , Malaria Falciparum/epidemiología , Malaria Falciparum/parasitología , Malaria Vivax/parasitología
4.
J Infect Dis ; 225(2): 257-268, 2022 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-34244739

RESUMEN

BACKGROUND: Plasmodium falciparum malaria dominates throughout sub-Saharan Africa, but the prevalence of Plasmodium malariae, Plasmodium ovale spp., and Plasmodium vivax increasingly contribute to infection in countries that control malaria using P. falciparum-specific diagnostic and treatment strategies. METHODS: We performed quantitative polymerase chain reaction (qPCR) on 2987 dried blood spots from the 2015-2016 Malawi Demographic and Health Survey to identify presence and distribution of nonfalciparum infection. Bivariate models were used to determine species-specific associations with demographic and environmental risk factors. RESULTS: Nonfalciparum infections had broad spatial distributions. Weighted prevalence was 0.025 (SE, 0.004) for P. malariae, 0.097 (SE, 0.008) for P. ovale spp., and 0.001 (SE, 0.0005) for P. vivax. Most infections (85.6%) had low-density parasitemias ≤ 10 parasites/µL, and 66.7% of P. malariae, 34.6% of P. ovale spp., and 40.0% of P. vivax infections were coinfected with P. falciparum. Risk factors for P. malariae were like those known for P. falciparum; however, there were few risk factors recognized for P. ovale spp. and P. vivax, perhaps due to the potential for relapsing episodes. CONCLUSIONS: The prevalence of any nonfalciparum infection was 11.7%, with infections distributed across Malawi. Continued monitoring of Plasmodium spp. becomes critical as nonfalciparum infections become important sources of ongoing transmission.


Asunto(s)
Malaria/epidemiología , Plasmodium malariae/aislamiento & purificación , Plasmodium ovale/aislamiento & purificación , Plasmodium vivax/aislamiento & purificación , Adolescente , Adulto , Femenino , Humanos , Malaria/diagnóstico , Malaria Vivax/epidemiología , Malaui/epidemiología , Masculino , Plasmodium malariae/genética , Plasmodium ovale/genética , Plasmodium vivax/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Adulto Joven
5.
Malar J ; 21(1): 80, 2022 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-35264152

RESUMEN

BACKGROUND: Transmission of malaria in sub-Saharan Africa has become increasingly stratified following decades of malaria control interventions. The extent to which environmental and land cover risk factors for malaria may differ across distinct strata of transmission intensity is not well known and could provide actionable targets to maximize the success of malaria control efforts. METHODS: This study used cross-sectional malaria survey data from a nationally representative cohort of school-aged children in Tanzania, and satellite-derived measures for environmental features and land cover. Hierarchical logistic regression models were applied to evaluate associations between land cover and malaria prevalence within three distinct strata of transmission intensity: low and unstable, moderate and seasonal, and high and perennial. RESULTS: In areas with low malaria transmission, each 10-percentage point increase in cropland cover was associated with an increase in malaria prevalence odds of 2.44 (95% UI: 1.27, 5.11). However, at moderate and higher levels of transmission intensity, no association between cropland cover and malaria prevalence was detected. Small associations were observed between greater grassland cover and greater malaria prevalence in high intensity settings (prevalence odds ratio (POR): 1.10, 95% UI: 1.00, 1.21), and between greater forest cover and reduced malaria prevalence in low transmission areas (POR: 0.74, 95% UI: 0.51, 1.03), however the uncertainty intervals of both estimates included the null. CONCLUSIONS: The intensity of malaria transmission appears to modify relationships between land cover and malaria prevalence among school-aged children in Tanzania. In particular, greater cropland cover was positively associated with increased malaria prevalence in areas with low transmission intensity and presents an actionable target for environmental vector control interventions to complement current malaria control activities. As areas are nearing malaria elimination, it is important to re-evaluate environmental risk factors and employ appropriate interventions to effectively address low-level malaria transmission.


Asunto(s)
Malaria , Niño , Estudios Transversales , Humanos , Malaria/epidemiología , Prevalencia , Factores de Riesgo , Tanzanía/epidemiología
6.
J Infect Dis ; 223(6): 1005-1014, 2021 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-32766832

RESUMEN

BACKGROUND: Plasmodium ovale is an understudied malaria species prevalent throughout much of sub-Saharan Africa. Little is known about the distribution of ovale malaria and risk factors for infection in areas of high malaria endemicity. METHODS: Using the 2013 Democratic Republic of the Congo (DRC) Demographic and Health Survey, we conducted a risk factor analysis for P. ovale infections. We evaluated geographic clustering of infections and speciated to P. ovale curtisi and P. ovale wallikeri through deep sequencing. RESULTS: Of 18 149 adults tested, we detected 143 prevalent P. ovale infections (prevalence estimate 0.8%; 95% confidence interval [CI], .59%-.98%). Prevalence ratios (PR) for significant risk factors were: male sex PR = 2.12 (95% CI, 1.38-3.26), coprevalent P. falciparum PR = 3.52 (95% CI, 2.06-5.99), and rural residence PR = 2.19 (95% CI, 1.31-3.66). P. ovale was broadly distributed throughout the DRC; an elevated cluster of infections was detected in the south-central region. Speciation revealed P. ovale curtisi and P. ovale wallikeri circulating throughout the country. CONCLUSIONS: P. ovale persists broadly in the DRC, a high malaria burden country. For successful elimination of all malaria species, P. ovale needs to be on the radar of malaria control programs.


Asunto(s)
Malaria , Plasmodium ovale , Adulto , República Democrática del Congo/epidemiología , Humanos , Malaria/epidemiología , Prevalencia
7.
Clin Infect Dis ; 73(11): e3966-e3969, 2021 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-33238298

RESUMEN

In a cross-sectional molecular study in the Democratic Republic of the Congo, 78% of households had ≥1 member infected with Plasmodium falciparum, Plasmodium vivax, and/or Plasmodium ovale spp.; 47% of children and 33% of adults tested positive for ≥1 species. Risk factors varied by species and age group.


Asunto(s)
Malaria Falciparum , Plasmodium ovale , Adulto , Niño , Estudios Transversales , República Democrática del Congo/epidemiología , Humanos , Malaria Falciparum/epidemiología , Plasmodium falciparum/genética , Plasmodium ovale/genética , Plasmodium vivax , Prevalencia
8.
Emerg Infect Dis ; 21(12): 2213-6, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26583383

RESUMEN

Francisella tularensis DNA extractions and isolates from the environment and humans were genetically characterized to elucidate environmental sources that cause human tularemia in Turkey. Extensive genetic diversity consistent with genotypes from human outbreaks was identified in environmental samples and confirmed water as a source of human tularemia in Turkey.


Asunto(s)
Francisella tularensis/patogenicidad , Tularemia/epidemiología , Enfermedades Transmitidas por el Agua/epidemiología , Animales , Brotes de Enfermedades , Genotipo , Humanos , Filogeografía/métodos , Roedores , Turquía/epidemiología , Agua , Enfermedades Transmitidas por el Agua/genética
9.
Am J Trop Med Hyg ; 111(2): 361-364, 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-38861981

RESUMEN

Increasing sulfadoxine-pyrimethamine (SP) resistance in the Democratic Republic of the Congo (DRC) has threatened its use for prevention of malaria in one of the most malarious countries in the world. Using geographic information on mining operations in the DRC and genetic data on SP drug resistance markers from the 2013-2014 Demographic and Health Surveys, we evaluated associations between close residence to mining and the presence of mutations conferring resistance to sulfadoxine. Close residential proximity to mining was associated with increased prevalence odds ratio (POR) of the dhps540E mutation (POR: 2.11, 95% uncertainty interval: 1.15-3.96) with adjustments for confounding variables and space. Our findings indicate that exposure to mining is associated with increased presence of an antimalarial drug resistance haplotype that threatens effective use of SP for vulnerable populations. Areas actively engaged in mining could be considered for interventions to reduce the spread of emerging drug resistance in the DRC.


Asunto(s)
Antimaláricos , Resistencia a Medicamentos , Minería , Mutación , Pirimetamina , Sulfadoxina , República Democrática del Congo/epidemiología , Humanos , Antimaláricos/uso terapéutico , Antimaláricos/farmacología , Resistencia a Medicamentos/genética , Pirimetamina/farmacología , Pirimetamina/uso terapéutico , Sulfadoxina/uso terapéutico , Sulfadoxina/farmacología , Prevalencia , Plasmodium falciparum/genética , Plasmodium falciparum/efectos de los fármacos , Dihidropteroato Sintasa/genética , Combinación de Medicamentos , Malaria Falciparum/epidemiología , Malaria Falciparum/parasitología , Femenino
10.
Clin Toxicol (Phila) ; : 1-8, 2024 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-39316835

RESUMEN

INTRODUCTION: Envenomation after a North American rattlesnake (Crotalus spp. and Sistrusus spp.) bite is associated with substantial morbidity. Arizona reports the highest number of rattlesnake envenomations annually in the United States. We evaluated the performance of poison and drug information centers for snakebite surveillance, compared with the hospital and emergency department discharge database. We used both datasets to improve the characterization of epidemiology, healthcare costs, and clinical effects of snakebite envenomations in Arizona. METHODS: We identified patients with a snakebite during 2017-2021 using Arizona hospital and emergency department discharge data and snakebite consults with two regional Arizona poison centers. Patients were matched using name and birthdate. The performance of poison center data for snakebite surveillance was evaluated using the percentage of snakebite patients in hospital and emergency department discharge data that consulted with poison centers. Patient demographics, healthcare characteristics, clinical effects, and context of snakebite events were described using both datasets. RESULTS: In total, 1,288 patients with a snakebite were identified using the Arizona hospital and emergency department discharge data, which resulted in 953 (74%) consultations with poison centers. The median age of patients was 48 years (IQR 28-62 years), and they were predominantly male (66%), White (90%), and non-Hispanic (84%). The median billed charges were US$ 84,880 (IQR US$ 13,286-US$ 168,043); the median duration of a healthcare stay was 34 h (IQR 13-48 h), and 29% of patients were transferred between healthcare facilities. Among 953 consulted poison center calls for a snakebite, a median of 14 vials of antivenom was administered per patient; 375 (60%) bites occurred near the home, and 345 (43%) patients were bitten on a lower extremity. One death was identified. DISCUSSION: Snakebites in Arizona can cause severe morbidity and require extensive healthcare resources for treatment. Poison centers are valuable for monitoring venomous snakebites in Arizona. CONCLUSIONS: Using hospital and emergency department discharge data with poison center records can improve public health surveillance data regarding snakebite epidemiology and human-snake interaction information and be used to tailor interventions to increase awareness of snake encounters and prevent snakebites.

11.
Am J Trop Med Hyg ; 110(5): 887-891, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38507797

RESUMEN

As part of malaria nationwide monitoring and evaluation initiatives, there is an increasing trend of incorporating malaria rapid diagnostic tests (mRDTs) in surveys conducted within primary schools to detect malaria parasites. However, mRDTs based on the detection of histidine-rich protein 2 (HRP2) are known to yield false-positive results due to persistent antigenemia, and false-negative results may result from low parasitemia or Plasmodium falciparum hrp2/3 gene deletion. We evaluated diagnostic performance of an HRP2 and pan-parasite lactate dehydrogenase (HRP2/pLDH) mRDT against polymerase chain reaction (PCR) for detection of P. falciparum among 17,051 primary school-age children from eight regions of Tanzania in 2017. According to PCR, the prevalence of P. falciparum was 19.2% (95% CI: 18.6-19.8). Using PCR as reference, the sensitivity and specificity of mRDT was 76.2% (95% CI: 74.7-77.7) and 93.9% (95% CI: 93.5-94.3), respectively. Test agreement was lowest in low transmission areas, where true-positive mRDTs were outnumbered by false-negatives due to low parasitemia. Discordant samples (mRDT-negative but PCR-positive) were screened for pfhrp2/3 deletion by real-time PCR. Among those with a parasite density sufficient for analysis, pfhrp2 deletion was confirmed in 60 samples, whereas pfhrp3 deletion was confirmed in two samples; one sample had both pfhrp2 and pfhrp3 deletions. The majority of samples with gene deletions were detected in the high-transmission Kagera region. Compared with mRDTs, PCR and other molecular methods offer increased sensitivity and are not affected by pfhrp2/3 deletions, making them a useful supplement to mRDTs in schools and other epidemiological surveys.


Asunto(s)
Antígenos de Protozoos , Malaria Falciparum , Plasmodium falciparum , Proteínas Protozoarias , Niño , Femenino , Humanos , Masculino , Antígenos de Protozoos/genética , Eliminación de Gen , Malaria Falciparum/diagnóstico , Malaria Falciparum/epidemiología , Plasmodium falciparum/genética , Plasmodium falciparum/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Prevalencia , Proteínas Protozoarias/genética , Prueba de Diagnóstico Rápido , Instituciones Académicas , Sensibilidad y Especificidad , Tanzanía/epidemiología
12.
Lancet Microbe ; 4(7): e516-e523, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37269868

RESUMEN

BACKGROUND: Domesticated animal ownership is an understudied aspect of the human environment that influences mosquito biting behaviour and malaria transmission, and is a key part of national economies and livelihoods in malaria-endemic regions. In this study, we aimed to understand differences in Plasmodium falciparum prevalence by ownership status of common domesticated animals in DR Congo, where 12% of the world's malaria cases occur and anthropophilic Anopheles gambiae vectors predominate. METHODS: In this cross-sectional study, we used survey data from individuals aged 15-59 years in the most recent (2013-14) DR Congo Demographic and Health Survey and previously performed Plasmodium quantitative real-time PCR (qPCR) to estimate P falciparum prevalence differences by household ownership of cattle; chickens; donkeys, horses, or mules; ducks; goats; sheep; and pigs. We used directed acyclic graphs to consider confounding by age, gender, wealth, modern housing, treated bednet use, agricultural land ownership, province, and rural location. FINDINGS: Of 17 701 participants who had qPCR results and covariate data, 8917 (50·4%) of whom owned a domesticated animal, we observed large differences in malaria prevalence across types of animals owned in both crude and adjusted models. Household chicken ownership was associated with 3·9 (95% CI 0·6 to 7·1) more P falciparum infections per 100 people, whereas cattle ownership was associated with 9·6 (-15·8 to -3·5) fewer P falciparum infections per 100 people, even after accounting for bednet use, wealth, and housing structure. INTERPRETATION: Our finding of a protective association conferred by cattle ownership suggests that zooprophylaxis interventions might have a role in DR Congo, possibly by drawing An gambiae feeding away from humans. Studies of animal husbandry practices and associated mosquito behaviours could reveal opportunities for new malaria interventions. FUNDING: The National Institutes of Health and the Bill & Melinda Gates Foundation. TRANSLATIONS: For the French and Lingala translations of the abstract see Supplementary Materials section.


Asunto(s)
Malaria , Parásitos , Estados Unidos , Humanos , Animales , Bovinos , Caballos , Porcinos , Ovinos , Plasmodium falciparum , Animales Domésticos , Estudios Transversales , República Democrática del Congo/epidemiología , Prevalencia , Propiedad , Mosquitos Vectores , Pollos , Cabras
13.
Sci Rep ; 12(1): 1737, 2022 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-35110617

RESUMEN

Extraction of natural resources through mining and logging activities provides revenue and employment across sub-Saharan Africa, a region with the highest burden of malaria globally. The extent to which mining and logging influence malaria transmission in Africa remains poorly understood. Here, we evaluate associations between mining, logging, and malaria in the high transmission setting of the Democratic Republic of the Congo using population-representative malaria survey results and geographic data for environmental features and mining and logging concessions. We find elevated malaria prevalence among individuals in rural areas exposed to mining; however, we also detect significant spatial confounding among locations. Upon correction, effect estimates for mining and logging shifted toward the null and we did not find sufficient evidence to detect an association with malaria. Our findings reveal a complex interplay between mining, logging, space, and malaria prevalence. While mining concessions alone may not drive the high prevalence, unobserved features of mining-exposed areas, such as human migration, changing vector populations, or parasite genetics, may instead be responsible.


Asunto(s)
Industria Procesadora y de Extracción , Malaria/epidemiología , Adolescente , Adulto , Estudios Transversales , República Democrática del Congo/epidemiología , Femenino , Humanos , Malaria/diagnóstico , Malaria/parasitología , Malaria/transmisión , Masculino , Persona de Mediana Edad , Minería , Prevalencia , Medición de Riesgo , Factores de Riesgo , Madera , Adulto Joven
14.
J Med Entomol ; 59(2): 615-622, 2022 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-34958094

RESUMEN

Long lasting permethrin-impregnated (LLPI) clothing can retain permethrin and repel ticks for up to three months and without exceeding EPA-approved safe levels; however, little is known about longer term effects of wearing LLPI clothing. Here, permethrin content was measured in new forester pants soon after initial impregnation (Insect Shield) and again one year later after being repeatedly worn by foresters in the field. Urine samples were collected from foresters for biomonitoring of permethrin metabolites at multiple time intervals (pre-use, one-month, three-to-four-months, and one-year post-use). Lethality against nymphal Ixodes scapularis Say was measured in clothing after one year of wear by foresters. Furthermore, to test potential variability in permethrin impregnation of different batches of clothing, separate sets of clothing were anonymously sent to Insect Shield for permethrin treatment over a period of three months and permethrin was quantified. Results demonstrated 33% of participants' pants had no measurable permethrin after one year of wear and permethrin content and tick mortality varied significantly between clothing. Only two of the participants' clothing resulted in ≥ 30% tick mortality after one year of wear. Significant differences were observed in 3-PBA and trans-DCCA, but not cis-DCCA metabolites in participants over the four measured time points and were higher than general United States population levels. This study provides practical information on the safety (measured by urinary metabolites) over time of LLPI clothing. It also provides snapshots (pre-washing and after one year of wear) of effectiveness of LLPI clothing as personal protective equipment against ticks for outdoor workers.


Asunto(s)
Insecticidas , Ixodes , Mordeduras de Garrapatas , Animales , Vestuario , Humanos , Insecticidas/farmacología , Permetrina/farmacología , Ropa de Protección , Mordeduras de Garrapatas/prevención & control
15.
PLoS Negl Trop Dis ; 16(10): e0010790, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36223421

RESUMEN

Acute febrile illness is a common problem managed by clinicians and health systems globally, particularly in the Tropics. In many regions, malaria is a leading and potentially deadly cause of fever; however, myriad alternative etiologies exist. Identifying the cause of fever allows optimal management, but this depends on many factors including thorough knowledge of circulating infections. Arboviruses such as dengue (DENV) cause fever and may be underdiagnosed in sub-Saharan Africa where malaria is a major focus. We examined cases of fever in western Cameroon that tested negative for malaria and found 13.5% (13/96) were due to DENV, with 75% (9/12) of these being DENV serotype 2 infections. Two complete DENV2 genomes were obtained and clustered closely to recent isolates from Senegal and Burkina Faso. The seroprevalence of DENV in this region was 24.8% (96/387). Neutralizing antibodies to DENV2 were detected in all (15/15) seropositive samples tested. Chikungunya (CHIKV) is an arthritogenic alphavirus that is transmitted by Aedes mosquitoes, the same principal vector as DENV. The seroprevalence for CHIKV was 15.7% (67/427); however, CHIKV did not cause a single case of fever in the 96 subjects tested. Of note, being seropositive for one arbovirus was associated with being seropositive for the other (Χ2 = 16.8, p<0.001). Taken together, these data indicate that Aedes-transmitted arboviruses are endemic in western Cameroon and are likely a common but underappreciated cause of febrile illness. This work supports the need for additional study of arboviruses in sub-Saharan Africa and efforts to improve diagnostic capacity, surveillance systems, and arbovirus prevention strategies.


Asunto(s)
Aedes , Arbovirus , Fiebre Chikungunya , Coinfección , Dengue , Malaria , Animales , Humanos , Estudios Seroepidemiológicos , Camerún/epidemiología , Coinfección/epidemiología , Mosquitos Vectores , Fiebre/epidemiología , Anticuerpos Neutralizantes
16.
Nat Commun ; 12(1): 4169, 2021 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-34234124

RESUMEN

Reports of P. vivax infections among Duffy-negative hosts have accumulated throughout sub-Saharan Africa. Despite this growing body of evidence, no nationally representative epidemiological surveys of P. vivax in sub-Saharan Africa have been performed. To overcome this gap in knowledge, we screened over 17,000 adults in the Democratic Republic of the Congo (DRC) for P. vivax using samples from the 2013-2014 Demographic Health Survey. Overall, we found a 2.97% (95% CI: 2.28%, 3.65%) prevalence of P. vivax infections across the DRC. Infections were associated with few risk-factors and demonstrated a relatively flat distribution of prevalence across space with focal regions of relatively higher prevalence in the north and northeast. Mitochondrial genomes suggested that DRC P. vivax were distinct from circulating non-human ape strains and an ancestral European P. vivax strain, and instead may be part of a separate contemporary clade. Our findings suggest P. vivax is diffusely spread across the DRC at a low prevalence, which may be associated with long-term carriage of low parasitemia, frequent relapses, or a general pool of infections with limited forward propagation.


Asunto(s)
Portador Sano/epidemiología , Malaria Vivax/epidemiología , Parasitemia/epidemiología , Plasmodium vivax/aislamiento & purificación , Adolescente , Adulto , Factores de Edad , Portador Sano/diagnóstico , Portador Sano/parasitología , Estudios Transversales , República Democrática del Congo/epidemiología , Femenino , Humanos , Malaria Vivax/diagnóstico , Malaria Vivax/parasitología , Masculino , Tamizaje Masivo/estadística & datos numéricos , Parasitemia/parasitología , Prevalencia , Factores de Riesgo , Adulto Joven
17.
J Med Entomol ; 57(5): 1532-1538, 2020 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-32277701

RESUMEN

Tick-borne diseases are a growing threat to public health in the United States, especially among outdoor workers who experience high occupational exposure to ticks. Long-lasting permethrin-impregnated clothing has demonstrated high initial protection against bites from blacklegged ticks, Ixodes scapularis Say (Acari: Ixodidae), in laboratory settings, and sustained protection against bites from the lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), in field tests. However, long-lasting permethrin impregnation of clothing has not been field tested among outdoor workers who are frequently exposed to blacklegged ticks. We conducted a 2-yr randomized, placebo-controlled, double-blinded trial among 82 outdoor workers in Rhode Island and southern Massachusetts. Participants in the treatment arm wore factory-impregnated permethrin clothing, and the control group wore sham-treated clothing. Outdoor working hours, tick encounters, and bites were recorded weekly to assess protective effectiveness of long-lasting permethrin-impregnated garments. Factory-impregnated clothing significantly reduced tick bites by 65% in the first study year and by 50% in the second year for a 2-yr protective effect of 58%. No significant difference in other tick bite prevention method utilization occurred between treatment and control groups, and no treatment-related adverse outcomes were reported. Factory permethrin impregnation of clothing is safe and effective for the prevention of tick bites among outdoor workers whose primary exposure is to blacklegged ticks in the northeastern United States.


Asunto(s)
Insecticidas , Enfermedad de Lyme/prevención & control , Permetrina , Ropa de Protección , Mordeduras de Garrapatas/prevención & control , Adulto , Animales , Método Doble Ciego , Femenino , Humanos , Ixodes , Masculino , Persona de Mediana Edad , Control de Ácaros y Garrapatas
18.
Parasit Vectors ; 13(1): 470, 2020 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-32928302

RESUMEN

BACKGROUND: Alpha-gal is an oligosaccharide implicated in delayed anaphylaxis following red meat consumption. Exposure to tick bites has been correlated with development of an allergic response to alpha-gal. However, evidence prospectively linking exposure to a single tick species and an immune response to alpha-gal is lacking. METHODS: We used serum samples from a prior study cohort of outdoor workers in North Carolina, USA, with high exposure to the lone star tick, Amblyomma americanum, to prospectively evaluate the relationship between tick bites and anti-alpha-gal IgE antibodies. RESULTS: Individuals who reported exposure to one or more tick bites were significantly more likely to have a positive change in anti-alpha-gal IgE compared to individuals with no reported tick bites. This relationship was not dependent on time. A trend toward increasing number of tick bites and increased anti-alpha-gal IgE levels was observed but not statistically significant. CONCLUSION: To our knowledge, this is the first study to prospectively link documented exposure to A. americanum bites and increased sensitization to alpha-gal in a cohort of outdoor workers. Our results support the role of A. americanum as likely agents for eliciting an allergic response to red meat, and highlight the importance of preventing tick bites.


Asunto(s)
Amblyomma/fisiología , Hipersensibilidad a los Alimentos/etiología , Hipersensibilidad a los Alimentos/inmunología , Carne Roja/efectos adversos , Mordeduras de Garrapatas/complicaciones , Adulto , Amblyomma/inmunología , Animales , Bovinos , Disacáridos/inmunología , Agricultores , Femenino , Hipersensibilidad a los Alimentos/sangre , Humanos , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Masculino , Persona de Mediana Edad , North Carolina , Estudios Prospectivos , Mordeduras de Garrapatas/inmunología , Mordeduras de Garrapatas/parasitología
19.
Infect Control Hosp Epidemiol ; 41(3): 355-357, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31983363

RESUMEN

Healthcare personnel who perform invasive procedures and are living with HIV or hepatitis B have been required to self-notify the NC state health department since 1992. State coordinated review of HCP utilizes a panel of experts to evaluate transmission risk and recommend infection prevention measures. We describe how this practice balances HCP privacy and patient safety and health.


Asunto(s)
Adhesión a Directriz/estadística & datos numéricos , Infecciones por VIH/prevención & control , Personal de Salud/legislación & jurisprudencia , Política de Salud/legislación & jurisprudencia , Hepatitis B/prevención & control , Transmisión de Enfermedad Infecciosa de Profesional a Paciente/prevención & control , Atención a la Salud , Humanos , North Carolina , Seguridad del Paciente , Autoinforme
20.
PLoS Negl Trop Dis ; 11(12): e0006077, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29227994

RESUMEN

BACKGROUND: Genetic analysis of pathogenic organisms is a useful tool for linking human cases together and/or to potential environmental sources. The resulting data can also provide information on evolutionary patterns within a targeted species and phenotypic traits. However, the instruments often used to generate genotyping data, such as single nucleotide polymorphisms (SNPs), can be expensive and sometimes require advanced technologies to implement. This places many genotyping tools out of reach for laboratories that do not specialize in genetic studies and/or lack the requisite financial and technological resources. To address this issue, we developed a low cost and low tech genotyping system, termed agarose-MAMA, which combines traditional PCR and agarose gel electrophoresis to target phylogenetically informative SNPs. METHODOLOGY/PRINCIPAL FINDINGS: To demonstrate the utility of this approach for generating genotype data in a resource-constrained area (Madagascar), we designed an agarose-MAMA system targeting previously characterized SNPs within Yersinia pestis, the causative agent of plague. We then used this system to genetically type pathogenic strains of Y. pestis in a Malagasy laboratory not specialized in genetic studies, the Institut Pasteur de Madagascar (IPM). We conducted rigorous assay performance validations to assess potential variation introduced by differing research facilities, reagents, and personnel and found no difference in SNP genotyping results. These agarose-MAMA PCR assays are currently employed as an investigative tool at IPM, providing Malagasy researchers a means to improve the value of their plague epidemiological investigations by linking outbreaks to potential sources through genetic characterization of isolates and to improve understanding of disease ecology that may contribute to a long-term control effort. CONCLUSIONS: The success of our study demonstrates that the SNP-based genotyping capacity of laboratories in developing countries can be expanded with manageable financial cost for resource constraint laboratories. This is a practical formula that reduces resource-driven limitations to genetic research and promises to advance global collective knowledge of infectious diseases emanating from resource limited regions of the world.


Asunto(s)
Técnicas de Genotipaje/instrumentación , Peste/diagnóstico , Polimorfismo de Nucleótido Simple , Yersinia pestis/genética , Costos y Análisis de Costo , Electroforesis en Gel de Agar , Técnicas de Genotipaje/economía , Recursos en Salud , Humanos , Madagascar , Reacción en Cadena de la Polimerasa , Yersinia pestis/clasificación
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