Technical Limitations Associated With Molecular Barcoding of Arthropod Bloodmeals Taken From North American Deer Species.

Accurate species-level identification of the source of arthropod bloodmeals is important for deciphering blood feeding patterns of field-collected specimens. Cytochrome c oxidase I (COI) mitochondrial gene sequencing has been used for this purpose; however, species resolution can be difficult to obtain from certain vertebrate genera, including Odocoileus. Sanger sequencing of mitochondrial genes was employed to identify the bloodmeal source of wild-caught mosquitoes trapped in Greeley, Colorado. Initial sequencing of the COI gene of mitochondrial DNA in bloodmeals was inadequate for species-level resolution of bloodmeals from deer in the genus Odocoileus, with current databases returning low fidelity matches to multiple genera. The use of the hypervariable D loop of the control region provided species-level identification of white-tailed deer (Order: Artiodactyla, Family: Cervidae, Odocoileus virginianus); however, taxonomic identification was successful only to genus for mule (O. hemionus hemionus) and black-tailed deer (O. hemionus columbianus). We advocate the use of multiple loci for bloodmeal analysis and the buildout of available databases to include multiple mitochondrial reference genes for reliable host species identification.

Zika virus disease-associated Guillain-Barré syndrome-Barranquilla, Colombia 2015-2016.

BACKGROUND: An outbreak of Guillain-Barré syndrome (GBS), a disorder characterized by acute, symmetric limb weakness with decreased or absent deep-tendon reflexes, was reported in Barranquilla, Colombia, after the introduction of Zika virus in 2015. We reviewed clinical data for GBS cases in Barranquilla and performed a case-control investigation to assess the association of suspect and probable Zika virus disease with GBS. METHODS: We used the Brighton Collaboration Criteria to confirm reported GBS patients in Barranquilla during October 2015-April 2016. In April 2016, two neighborhood and age range-matched controls were selected for each confirmed GBS case-patient. We obtained demographics and antecedent symptoms in the 2-month period before GBS onset for case-patients and the same period for controls. Sera were collected for Zika virus antibody testing. Suspected Zika virus disease was defined as a history of rash and ≥2 other Zika-related symptoms (fever, arthralgia, myalgia, or conjunctivitis). Probable Zika virus disease was defined as suspected Zika virus disease with laboratory evidence of a recent Zika virus or flavivirus infection. Conditional logistic regression adjusted for sex and race/ethnicity was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: We confirmed 47 GBS cases. Incidence increased with age (10-fold higher in those ≥60years versus those <20years). We interviewed 40 case-patients and 79 controls. There was no significant difference in laboratory evidence of recent Zika virus or flavivirus infection between case-patients and controls (OR: 2.2; 95% CI: 0.9-5.1). GBS was associated with having suspected (OR: 3.0, 95% CI: 1.1-8.6) or probable Zika virus disease (OR: 4.6, CI: 1.1-19.0). CONCLUSIONS: Older individuals and those with suspected and probable Zika virus disease had higher odds of developing GBS. KEY POINTS: We confirmed a Guillain-Barré syndrome (GBS) outbreak in Barranquilla, Colombia, during October 2015-April 2016. A case-control investigation using neighborhood controls showed an association of suspected and probable Zika virus disease with GBS.

Increased rates of Guillain-Barré syndrome associated with Zika virus outbreak in the Salvador metropolitan area, Brazil.

In mid-2015, Salvador, Brazil, reported an outbreak of Guillain-Barré syndrome (GBS), coinciding with the introduction and spread of Zika virus (ZIKV). We found that GBS incidence during April-July 2015 among those ≥12 years of age was 5.6 cases/100,000 population/year and increased markedly with increasing age to 14.7 among those ≥60 years of age. We conducted interviews with 41 case-patients and 85 neighborhood controls and found no differences in demographics or exposures prior to GBS-symptom onset. A higher proportion of case-patients (83%) compared to controls (21%) reported an antecedent illness (OR 18.1, CI 6.9-47.5), most commonly characterized by rash, headache, fever, and myalgias, within a median of 8 days prior to GBS onset. Our investigation confirmed an outbreak of GBS, particularly in older adults, that was strongly associated with Zika-like illness and geo-temporally associated with ZIKV transmission, suggesting that ZIKV may result in severe neurologic complications.

Minimum infectious dose for chikungunya virus in Aedes aegypti and Ae. albopictus mosquitoes / Dosis infecciosa mínima del virus del chikungunya en los mosquitos Aedes aegypti y Ae. albopictus

Understanding the ability of the chikungunya virus (CHIKV) to be transmitted by Aedes vectors in the Americas is critical for assessing epidemiological risk. One element that must be considered is the minimum infectious dose of virus that can lead to transmission following the extrinsic incubation period. This study aimed to determine the minimum infection rate for the two Aedes species studied. The results revealed that doses as low as 3.9 log10 plaqueforming units per mL (pfu/mL) of an Asian genotype CHIKV strain can lead to transmission by Ae. albopictus, and doses of at least 5.3 log10 pfu/mL from the same strain are needed for transmission from Ae. aegypti. These low infecting doses suggest that infected individuals may be infectious for almost the entire period of their viremia, and therefore, to prevent further cases, measures should be taken to prevent them from getting bitten by mosquitoes during this period.

Comprender la capacidad del virus del chikungunya (CHIKV) de ser transmitido por los vectores del género Aedes en la Región de las Américas es fundamental para evaluar el riesgo epidemiológico. Un elemento que debe tenerse en cuenta es la dosis infecciosa mínima de virus que posibilita la transmisión después del período de incubación extrínseco. El objetivo de este estudio ha sido determinar la tasa de infección mínima para las dos especies del género Aedes estudiadas. Los resultados indican que bastan dosis de tan solo 3,9 log10 unidades formadoras de placas por mililitro (ufp/ml) de una cepa de CHIKV del genotipo asiático para que se produzca la transmisión por Ae. albopictus, en tanto que para la transmisión por Ae. aegypti se necesitan dosis de al menos 5,3 log10 ufp/ml de la misma cepa. Estas dosis bajas indican que las personas infectadas podrían conservar el potencial infeccioso prácticamente durante todo el período de viremia y, por consiguiente, a fin de prevenir más casos, habría que tomar medidas para impedir que reciban picaduras de mosquitos durante ese período.

Minimum infectious dose for chikungunya virus in Aedes aegypti and Ae. albopictus mosquitoes / Dosis infecciosa mínima del virus del chikungunya en los mosquitos Aedes aegypti y Ae. albopictus

ABSTRACT Understanding the ability of the chikungunya virus (CHIKV) to be transmitted by Aedes vectors in the Americas is critical for assessing epidemiological risk. One element that must be considered is the minimum infectious dose of virus that can lead to transmission following the extrinsic incubation period. This study aimed to determine the minimum infection rate for the two Aedes species studied. The results revealed that doses as low as 3.9 log10 plaque-forming units per mL (pfu/mL) of an Asian genotype CHIKV strain can lead to transmission by Ae. albopictus, and doses of at least 5.3 log10 pfu/mL from the same strain are needed for transmission from Ae. aegypti. These low infecting doses suggest that infected individuals may be infectious for almost the entire period of their viremia, and therefore, to prevent further cases, measures should be taken to prevent them from getting bitten by mosquitoes during this period.(AU)

RESUMEN Comprender la capacidad del virus del chikungunya (CHIKV) de ser transmitido por los vectores del género Aedes en la Región de las Américas es fundamental para evaluar el riesgo epidemiológico. Un elemento que debe tenerse en cuenta es la dosis infecciosa mínima de virus que posibilita la transmisión después del período de incubación extrínseco. El objetivo de este estudio ha sido determinar la tasa de infección mínima para las dos especies del género Aedes estudiadas. Los resultados indican que bastan dosis de tan solo 3,9 log10 unidades formadoras de placas por mililitro (ufp/ml) de una cepa de CHIKV del genotipo asiático para que se produzca la transmisión por Ae. albopictus, en tanto que para la transmisión por Ae. aegypti se necesitan dosis de al menos 5,3 log10 ufp/ml de la misma cepa. Estas dosis bajas indican que las personas infectadas podrían conservar el potencial infeccioso prácticamente durante todo el período de viremia y, por consiguiente, a fin de prevenir más casos, habría que tomar medidas para impedir que reciban picaduras de mosquitos durante ese período.(AU)

Venezuelan equine encephalitis virus activity in the Gulf Coast region of Mexico, 2003-2010.

Venezuelan equine encephalitis virus (VEEV) has been the causative agent for sporadic epidemics and equine epizootics throughout the Americas since the 1930s. In 1969, an outbreak of Venezuelan equine encephalitis (VEE) spread rapidly from Guatemala and through the Gulf Coast region of Mexico, reaching Texas in 1971. Since this outbreak, there have been very few studies to determine the northward extent of endemic VEEV in this region. This study reports the findings of serologic surveillance in the Gulf Coast region of Mexico from 2003-2010. Phylogenetic analysis was also performed on viral isolates from this region to determine whether there have been substantial genetic changes in VEEV since the 1960s. Based on the findings of this study, the Gulf Coast lineage of subtype IE VEEV continues to actively circulate in this region of Mexico and appears to be responsible for infection of humans and animals throughout this region, including the northern State of Tamaulipas, which borders Texas.