Hosts are typically coinfected by multiple parasite species whose interactions might be synergetic or antagonistic, producing unpredictable physiological and pathological impacts on the host. This ...study shows the interaction between Plasmodium spp. and Leucocytozoon spp. in birds experimentally infected or not infected with Mycoplasma gallisepticum.
In 1994, the bacterium Mycoplasma gallisepticum jumped from poultry to wild birds in which it caused a major epidemic in North America. Birds infected with M. gallisepticum show conjunctivitis as well as increased levels of corticosterone.
Malaria and other haemosporidia are widespread in birds, and chronic infections become apparent with the detectable presence of the parasite in peripheral blood in response to elevated levels of natural or experimental corticosterone levels.
Knowing the immunosuppressive effect of corticosterone on the avian immune system, we tested the hypothesis that chronic infections of Plasmodium spp. and Leucocytozoon spp. in house finches would respond to experimental inoculation with M. gallisepticum as corticosterone levels are known to increase following inoculation.
Plasmodium spp. infection intensity increased within days of M. gallisepticum inoculation as shown both by the appearance of infected erythrocytes and by the increase in the number and the intensity of positive PCR tests.
Leucocytozoon spp. infection intensity increased when Plasmodium spp. infection intensity increased, but not in response to M. gallisepticum inoculation. Leucocytozoon spp. and Plasmodium spp. seemed to compete in the host as shown by a negative correlation between the changes in their PCR score when both pathogens were present in the same individual.
Host responses to coinfection with multiple pathogens measured by the hematocrit and white blood cell count depended on the haemosporidian community composition. Host investment in the leukocyte response was higher in the single‐haemosporidia‐infected groups when birds were infected with M. gallisepticum.
A trade‐off was observed between the immune control of the chronic infection (Plasmodium spp./Leucocytozoon spp.) and the immune response to the novel bacterial infection (M. gallisepticum).
Hosts are typically coinfected by multiple parasites whose interactions might be synergetic or antagonistic, producing unpredictable impacts on the host. This study shows the interaction between Plasmodium spp. and Leucocytozoon spp. in birds experimentally infected or not infected with Mycoplasma gallisepticum.
Studies of avian haemosporidians allow understanding how these parasites affect wild bird populations, and if their presence is related to factors such as habitat loss, degradation and fragmentation, ...and climate change. Considering the importance of the highland Plateau of Mexico as part of the North American bird migratory route and as a region containing important habitat for numerous bird species, the purpose of this study was to document haemosporidian species richness and how habitat degradation, bird body condition, and distance from water sources correlate with bird parasitemia.
We assessed the presence of avian haemosporidians in three resident bird species through microscopy and PCR amplification of a fragment of the haemosporidian cytochrome b gene. Average parasitemia was estimated in each species, and its relationship with habitat degradation through grazing, bird body condition and distance from water bodies was assessed.
High levels of parasitemia were recorded in two of the three bird species included in this study. Four lineages of haemosporidians were identified in the study area with nearly 50 % prevalence. Areas with highly degraded shrublands and villages showed higher parasitemia relative to areas with moderately degraded shrublands. No strong relationship between parasitemia and distance from water bodies was observed. There were no significant differences in prevalence and parasitemia between the two bird species infected with the parasites. Two of the sequences obtained from the fragments of the parasite's cytochrome b gene represent a lineage that had not been previously reported.
Haemosporidian diversity in arid zones of the Mexican highland plateau is high. Shrubland habitat degradation associated to the establishment of small villages, as well as tree extraction and overgrazing in the surroundings of these villages, significantly enhances parasitemia of birds by haemosporidians.
To determine the time to reverse transcription-polymerase chain reaction (RT-PCR) negativity after the first positive RT-PCR test, factors associated with longer time to RT-PCR negativity, proportion ...of children seroconverting after proven severe acute respiratory syndrome coronavirus 2 infection, and factors associated with the lack of seroconversion.
The Epidemiological Study of Coronavirus in Children of the Spanish Society of Pediatrics is a multicenter study conducted in Spanish children to assess the characteristics of coronavirus disease 2019. In a subset of patients, 3 serial RT-PCR tests on nasopharyngeal swab specimens were performed after the first RT-PCR test, and immunoglobulin G serology for severe acute respiratory syndrome coronavirus 2 antibodies was performed in the acute and follow-up (<14 and ≥14 days after diagnosis) phase.
In total, 324 patients were included in the study. The median time to RT-PCR negativity was 17 days (IQR, 8-29 days), and 35% of patients remained positive more than 4 weeks after the first RT-PCR test. The probability of RT-PCR negativity did not differ across groups defined by sex, disease severity, immunosuppressive drugs, or clinical phenotype. Globally, 24% of children failed to seroconvert after infection. Seroconversion was associated with hospitalization, persistence of RT-PCR positivity, and days of fever.
Time to RT-PCR negativity was long, regardless of the severity of symptoms or other patient features. This finding should be considered when interpreting RT-PCR results in a child with symptoms, especially those with mild symptoms. Seroprevalence and postimmunization studies should consider that 11 in 4 infected children fail to seroconvert.
Hosts are typically co-parasitized by multiple species. Parasites can benefit or suffer from the presence of other parasites, which can reduce or increase the overall virulence due to competition or ...facilitation. Outcomes of new multi-parasite systems are seldom predictable. In 1994 the bacterium Mycoplasma gallisepticum jumped from poultry to songbirds in which it caused an epidemic throughout North America. Songbirds are often parasitized by hard ticks, and can act as reservoirs for tick-borne pathogens. We tested the hypothesis that Mycoplasma infection in house finches influences North America's most important tick vector Ixodes scapularis, by affecting the tick's feeding success, detachment behaviour and survival to the next stage. Most ticks detached during the daylight hours irrespective of the bird's disease status and time since infestation. Birds incrementally invested in anti-tick resistance mechanisms over the course of the experiment; this investment was made earlier in the Mycoplasma-infected birds. At higher tick densities, the feeding success on birds with more severe conjunctivitis was lower than in the uninfected birds. Throughout the experiment we found positive density dependent effects on the tick's feeding success. More diseased hosts suffered more from the tick infestations, as shown by reduced haematocrits. Three Mycoplasma-infected birds died during the weeks following the experiment, although all birds were kept in optimal housing conditions. Mycoplasma made the bird a less accessible and valuable host for ticks, which is an example of ecological interference. Therefore, Mycoplasma has the potential to ultimately reduce transmission outcomes of tick-borne pathogens via songbird hosts.
Male house finch Haemorhous mexicanus co-parasitized by the black-legged tick Ixodes scapularis and the conjunctivitis-causing Mycoplasma gallisepticum. Display omitted
•Songbird hosts show signs of acquired immunological resistance against ticks.•Resistance acquisition was accelerated under the influence of Mycoplasma.•Mycoplasma infection had no strong effects on diurnal detachments.•Mycoplasma made birds a less accessible and valuable host for ticks.•Virulence increased under co-parasitism on the same host tissues.
Mycoplasma gallisepticum, a pathogen of worldwide economic importance in poultry, is recovered in chickens, especially from the respiratory tract. Some strains, however, are specialized to other ...tissues and because it jumps from poultry to wild birds, the new strains also cause severe conjunctivitis in new hosts. Nevertheless, most studies of M. gallisepticum in wild birds use choanal swabs or combine choanal and conjunctival swabs to quantify bacterial load. Because the clinical signs associated with M. gallisepticum infection differ markedly between poultry and House Finches (Haemorhous mexicanus), we compared the bacterial load in choanal and conjunctival samples following experimental inoculation of House Finches with M. gallisepticum isolates originating from poultry or from House Finches. This allowed us to test two hypotheses: M. gallisepticum changed tissue tropism, or M. gallisepticum simply expanded its within-host niche. By comparing bacterial loads from choanal and conjunctival swabs in birds inoculated with one of a suite of M. gallisepticum isolates, we found support for hypothesis 2. The choanal loads in House Finches did not differ between isolates, while the conjunctival loads of birds inoculated with poultry isolates were lower than in birds inoculated with House Finch isolates. When measuring the bacterial load of M. gallisepticum in birds, it is important to sample and analyze separately choanal and conjunctival swabs, as quantifying bacterial loads in pooled samples may not provide reliable information on differences in virulence.
Ever since 1994, when the bacterial pathogen
jumped from poultry to wild birds, it has been assumed that the primary host species of this pathogen in wild North American birds was the house finch (
...), in which disease prevalence was higher than in any other bird species. Here we tested two hypotheses to explain a recent increase in disease prevalence in purple finches (
) around Ithaca, New York. Hypothesis 1 is that, as
evolved and became more virulent, it has also become better adapted to other finches. If this is correct, early isolates of
should cause less-severe eye lesions in purple finches than in house finches, while more-recent isolates should cause eye lesions of similar severity in the two species. Hypothesis 2 is that, as house finch abundance declined following the
epidemic, purple finches around Ithaca increased in abundance relative to house finches and purple finches are thus more frequently exposed to
-infected house finches. This would then lead to an increase in
prevalence in purple finches. Following an experimental infection with an early and a more-recent
isolate, eye lesions in purple finches were more severe than in house finches. This did not a support Hypothesis 1; similarly, an analysis of Project Feeder Watch data collected around Ithaca did not show differences in changes in purple and house finches' abundance since 2006, a result which does not support Hypothesis 2. We conclude that purple finch populations will, unlike those of house finches, not suffer a severe decline because of a
epidemic.
Las infecciones víricas constituyen una de las complicaciones más temidas de la transfusión de sangre. A pesar de los esfuerzos para reducir o eliminar este riesgo, hoy es un problema no resuelto. En ...Cuba, la selección médica del donante, la pesquisa de infecciones y la vigilancia postransfusión, son actividades que están debidamente documentadas, sin embargo, existen brechas en su realización desde el punto de vista gerencial, epidemiológico y de atención médica. Por las razones anteriores se desarrolló esta investigación, para organizar con enfoque sistémico la vigilancia de las infecciones transmitidas por transfusión, que permitirá mejor control de los donantes y mayor seguridad de la sangre. Se realizó un estudio de desarrollo dividido en tres etapas: diagnóstico, planificación y diseño. Se utilizaron técnicas cualitativas individuales y grupales. Se presenta el diseño del Sistema de Vigilancia. Se explican los cinco subsistemas básicos: diagnóstico clínico, laboratorio, estadístico, epidemiológico, técnico material y comunitario. Con el sistema propuesto, la provincia de Cienfuegos está contribuyendo al logro de uno de los objetivos inmediatos del Programa de Medicina Transfusional de Cuba, que es el establecimiento de un sistema de hemovigilancia en todo el país.
Introducción El análisis de las desigualdades en salud ha adquirido importancia ante la evidencia creciente de que, lejos de desaparecer, estas condiciones permanecen y en algunos países se han ...incrementado. Objetivos Examinar la influencia del sexo, la orientación sexual, la edad, la región de procedencia, el color de la piel, la ocupación y el nivel escolar de personas VIH positivas. Métodos Se realizó un estudio ecológico. El universo estuvo constituido por todos los diagnósticos de personas VIH positivas desde 1986 hasta el 2007. La información se obtuvo de la base de datos de VIH/sida del Ministerio de Salud Pública. Resultados El 80,57 % de los VIH positivos fueron hombres, manteniéndose la razón hombre/mujer de los contagiados por encima de la de la población cubana durante todo el período. El 84,34 % de los hombres infectados tenían relaciones sexuales con otros hombres, mientras que solamente una mujer declaró tener relaciones con otras mujeres. Los grupos de edades de 20 y 34 años fueron los de mayor incidencia. Existió predominio de las personas de color blanco diagnosticadas como VIH positivas (84,44 %). El mayor número de seropositivos diagnosticados, 15,90 %, provenía del sector de la salud. En La Habana coincidió el alto número de casos diagnosticados con su elevada densidad poblacional. Centro Habana, 10 de Octubre, Santa Clara, Habana Vieja y Plaza, fueron los municipios de mayor acumulado de personas VIH positivas del país, los cinco son urbanos y altamente poblados. Conclusiones Los hombres predominaron en la epidemia cubana, específicamente los que tienen sexo con otros hombres. Las personas de color blanco son las más diagnosticadas como VIH positivas. Tanto en las provincias como en los municipios, la mayor cantidad de casos generalmente proviene de regiones urbanas y densamente pobladas. El mayor número de seropositivos diagnosticados procede del sector de la salud.
El municipio de Boyeros adquirió su fisonomía actual, a partir de 1976, en que se estableció la nueva división política administrativa. Es uno de los municipios de Ciudad Habana, tiene una extensión ...territorial de 134,2 km 2 con una población de 187006 habitantes, limita al Norte con el municipio Cerro, al Sur con los municipios Bejucal y San Antonio de los Baños de provincia Habana, al Este con el municipio Arroyo Naranjo y al Oeste con los municipios de La Lisa y de Marianao. Es un municipio rico por su historia y tradiciones, acercarse a ellas y en particular a la historia del desarrollo de la Salud Pública es importante porque la memoria es una de las fuentes esenciales para la formación de los valores que identifican a los integrantes de un pueblo, de una nación, fundamentalmente a sus jóvenes. Por ello estos apuntes para la historia de la Salud Pública del municipio Boyeros referirán los hitos más significativos de ese proceso desde la Colonia hasta la actualidad.
Marina Samuel Noble, gloria del deporte cubano Teresa Reinoso Domínguez; Marxlenin Gómez Martínez; Noel García Morales
Revista habanera de ciencias médicas,
11/2009, Letnik:
8, Številka:
2
Journal Article
Recenzirano
Odprti dostop
En 1984, ingresa al claustro de profesores del Instituto Superior de Ciencias
Médicas de La Habana una joven mujer de pequeña estatura, jovial y dinámica,
respetada y querida por todos, La gacela de ...Morón, atleta de renombre
nacional e internacional de nuestro país.
Marina Samuel Noble nace el 14 de diciembre de 1947 en el seno de una
familia de origen campesino, en una colonia cañera del Central Punta Alegre,
término municipal de Morón; sus padres Alfredo y Luisa trabajadores del
campo, de nacionalidad jamaicana. Crece rodeada de limitaciones económicas. Con solo 11 años participa activamente en las tareas de la Revolución,
alfabetiza y se integra a los CDR y la FMC.
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