Fiebres virales hemorrágicas en Suramérica

This paper reviews the epidemiology and distinguishing features of three viral hemorrhagic fevers (dengue hemorrhagic fever, yellow fever and arenaviral hemorrhagic fever) that have emerged as important public health problems in South America. Although the etiology, natural history and control of the three diseases are different, their clinical manifestations and histopathology findings are similar and can be difficult to differentiate. Consequently, early recognition and correct diagnosis are essential for effective control measures to be initiated.El artículo revisa la epidemiología y rasgos distintivos de tres fiebres virales hemorrágicas (dengue hemorrágico, fiebre amarilla y fiebre hemorrágica por arenavirus), que han emergido como serios problemas de salud pública en Suramérica. Aunque la etiología, la historia natural y el control de estas tres enfermedades difieren, sus manifestaciones clínicas y los hallazgos histopatológicos son similares y pueden ser difíciles de diferenciar. En consecuencia, la detección temprana y el diagnóstico correcto son esenciales para la aplicación de medidas de control

Efectos de la temperatura y la dieta sobre el crecimiento y la longevidad de flebotomíneos (Diptera: Psychodidae)

A series of experiments were done to study the effects of different ambient temperatures (28 to 10 °C) and diets on the growth rate, size and longevity of phlebotomine sand flies. Four different laboratory colonies of these insects were used: Phlebotomuspapatasi, Pperniciosus, Lutzomyia longipalpis (Brazil) and L. longipalpis (Colombia). The developmental times and survival of the insects were highly variable, depending on the temperature as well as species. At 18 °C and below, most of the L. longipalpis larvae and pupae died. At 15 ""C, the developmental time of P papatasiand Pperniciosus was markedly prolonged (150 to 412 days) and many of the immature forms died. Within a range of 28 to 15 °C, the longevity of adult P. papatasi and L. longipalpis increased as the ambient temperature decreased; to 15 ""C; the mean survival times of P. papatasi and L. longipalpis females were 63.2 and 37.1 days, respectively. The effect of two different diets (animal feceslliver powder and decomposing leaves) on the growth rate and size (pupal weight) of L. longipalpis was also determined. lnsects maintained on the diet of animal feceslliver powder developed faster, were more synchronous and were larger than those fed on decomposing leaves. Results of this study provide new information on the effects of environmental factors on the growth and longevity of phlebotomine sand flies under laboratory conditions.Se realizó una serie de experimentos para estudiar los efectos de diferentes temperaturas ambientales (28 a 10°C) y tipos de dieta sobre la tasa de crecimiento, el tamaño y la longevidad de los flebotomineos. Se utilizaron cuatro colonias de laboratorio diferentes: Phlebotomus papatasi, P perniciosus, Lutzomyia longipalpis (Brasil) y L. longipalpis (Colombia). Los períodos de desarrollo y supervivencia de los insectos fueron muy variables según la temperatura y la especie. Por debajo de 18 ""C, la mayoría de las larvas y pupas de L. longipalpis murieron. A 15 ""C, el tiempo de desarrollo de P papatasi y P perniciosus se prolongó considerablemente (150 a 41 2 dias) y muchas de las formas inmaduras murieron. En el rango de 28 a 15 °C, la longevidad de los adultos de P papatasi y L. longipalpis aumentó a medida que la temperatura ambiente disminuía; a 15 °C los tiempos promedio de supervivencia de las hembras de P papatasi y L. longipalpis fueron de 632 y 37,l dias, respectivamente. El efecto de dos tipos de dieta diferentes (heces de animallpolvo de hígado y hojas en descomposición) sobre la tasa de crecimiento y el tamaño (peso de la pupa) de L. longipalpis también se determinó, estableciéndose que los insectos alimentados con heces de anirnallpolvo de higado se desarrollaron más rápido y fueron más sincronizados y más grandes que aquellos alimentados con hojas en descompisición. Los resultados de este estudio entregan nueva información sobre los efectos de factores medioambientales en el crecimiento y la longevidad de lebotomineos bajo condiciones de laboratorio

Biting rates and developmental substrates for biting midges (Diptera: Ceratopogonidae) in Iquitos, Peru

Biting midges (Diptera: Ceratopogonidae) were collected at 16 periurban and rural sites around Iquitos, Peru, between 17 October 1996 and 26 May 1997. Culicoides paraensis (Goeldi), the principal vector of Oropouche virus, was the most commonly collected species (9,086 flies) with Culicoides insinuatus Wirth & Blanton second (7,229 flies). Although both species were collected at all sampling sites (linear distance surveyed ≈25 km), C. paraensis dominated at northern collection sites (>90%), whereas C. insinuatus prevailed at southern collection sites (>60%). C. paraensis were collected from human sentinels at a constant rate throughout daylight hours, at similar rates during wet and dry months, and regardless of rainfall. Larval developmental substrates for C. paraensis included decaying platano (Musa X paradisiaca L. [Musaceae]) stems, stumps, flowers, fruits, and debris beneath platano trees as well as from soil beneath a fruiting mamay (Syzygium malaccense Merr. & Perry [Myrtaceae]) tree and organic-rich mud along a lake shoreline. C. insinuatus adults likewise emerged from decaying platano and organic-rich mud along a lake shoreline, but also from debris accumulated in the axils of aguaje (Mauritia flexuosa L. [Palmae]) fronds and decaying citrus fruit. Despite high numbers of biting adults near putative substrates, adults of neither species emerged from other decomposing plant material, soil, phytotelmata, or artificial containers. Because both species of biting midges emerged in high numbers from all parts of platano (ubiquitous in Iquitos), it will be challenging to control them through sanitation.Instituto de Limnología "Dr. Raul A. Ringuelet

Venezuelan Equine Encephalitis in Panama: Fatal Endemic Disease and Genetic Diversity of Etiologic Viral Strains

Venezuelan equine encephalitis (VEE) is a reemerging, mosquito-borne viral disease of the neotropics that is severely debilitating and sometimes fatal to humans. Periodic epidemics mediated by equine amplification have been recognized since the 1920s, but interepidemic disease is rarely recognized. We report here clinical findings and genetic characterization of 42 cases of endemic VEE detected in Panama from 1961–2004. Recent clusters of cases occurred in Darien (eastern Panama) and Panama provinces (central Panama) near rainforest and swamp habitats. Patients ranged from 10 months to 48 years of age, and the more severe cases with neurological complications, including one fatal infection, were observed in children. The VEE virus strains isolated from these cases all belonged to an enzootic, subtype ID lineage known to circulate among sylvatic vectors and rodent reservoir hosts in Panama and Peru. These findings underscore endemic VEE as an important but usually neglected arboviral disease of Latin America

Family Cluster of Mayaro Fever, Venezuela

A cluster of protracted migratory polyarthritis involving four adult family members occurred in January 2000 after a brief overnight outing in a rural area of Venezuela. Laboratory testing demonstrated Mayaro virus as the cause of the cluster. These results documented the first human cases of Mayaro virus in Venezuela

Experimental Everglades Virus Infection of Cotton Rats (Sigmodon hispidus)

We characterized Everglades virus infection of cotton rats from South Florida to validate their role as reservoir hosts in the enzootic transmission cycle

Experimental Infection of Prairie Dogs with Monkeypox Virus

Infected prairie dogs can transmit monkeypox virus by respiratory and mucocutaneous contact with susceptible animals and humans

VIPR: A probabilistic algorithm for analysis of microbial detection microarrays

<p>Abstract</p> <p>Background</p> <p>All infectious disease oriented clinical diagnostic assays in use today focus on detecting the presence of a single, well defined target agent or a set of agents. In recent years, microarray-based diagnostics have been developed that greatly facilitate the highly parallel detection of multiple microbes that may be present in a given clinical specimen. While several algorithms have been described for interpretation of diagnostic microarrays, none of the existing approaches is capable of incorporating training data generated from positive control samples to improve performance.</p> <p>Results</p> <p>To specifically address this issue we have developed a novel interpretive algorithm, VIPR (<b>V</b>iral <b>I</b>dentification using a <b>PR</b>obabilistic algorithm), which uses Bayesian inference to capitalize on empirical training data to optimize detection sensitivity. To illustrate this approach, we have focused on the detection of viruses that cause hemorrhagic fever (HF) using a custom HF-virus microarray. VIPR was used to analyze 110 empirical microarray hybridizations generated from 33 distinct virus species. An accuracy of 94% was achieved as measured by leave-one-out cross validation. <it>Conclusions</it></p> <p>VIPR outperformed previously described algorithms for this dataset. The VIPR algorithm has potential to be broadly applicable to clinical diagnostic settings, wherein positive controls are typically readily available for generation of training data.</p

Yellow Fever Virus Infectivity for Bolivian Aedes aegypti Mosquitoes

The absence of urban yellow fever virus (YFV) in Bolivian cities has been attributed to the lack of competent urban mosquito vectors. Experiments with Aedes aegypti from Santa Cruz, Bolivia, demonstrated infection (100%), dissemination (20%), and transmission of a Bolivian YFV strain (CENETROP-322)