Transmission of Porcine reproductive and respiratory syndrome virus 1 to and from vaccinated pigs in a one-to-one model.

The present study examined transmission by contact of Porcine reproductive and respiratory syndrome virus (PRRSV) 1 in a one-to-one model to vaccinated and unvaccinated pigs and from vaccinated infected pigs to other vaccinated pigs. The experiment started by randomly assigning weaned pigs to groups V (n=24) and U (n=26). V pigs were vaccinated with a commercial live attenuated PRRSV vaccine and the U animals were kept as unvaccinated controls. Twenty-eight days later, 6U pigs were separated and allocated in individual boxes. The remaining 20U pigs were intranasally inoculated with PRRSV isolate 3267 (from now on designated as seeder (S) pigs) and 48h later were distributed in boxes where they were commingled with either V or U pigs in 1:1 groups (first contact phase), resulting in 6S:U and 14S:V pairs. As soon as a V pig was detected to be viremic because of contact with a S, the infected V (from now on designated as Vinf) was transferred (<24h after detection) to a new pen where it was comingled with a new V pig (designated as V2) in a second contact phase. For the first contact phase, pigs were maintained 21days at maximum and for the second contact phase the maximum exposure period was 14days. Two V pigs tested positive for the vaccine virus (>99.5% similarity) when they were relocated with the corresponding V2 pigs and they were removed; thus, only 12Vinf were finally considered. All V pigs (12/12) exposed to S animals became infected although the first detection of viremia occurred at 13.6±3.6days, one week later than in U (p<0.05). Also, duration of viremia was shorter for Vinf compared to U, (5.5±4.3days versus 12.5±2.7days). The Vinf group showed remarkable individual variability: eight animals had a viremic period of 5 or less days (3.0±1.4) while the remaining four had a longer viremic period of more than one week (10.8±2.9). This situation was not observed in U. In the second contact phase, transmission from Vinf to V2 pigs occurred in 7/8 cases (87.5%). The mean duration of viremia for V2 was 4.8±3.4 and two different patterns were again observed: two animals had viremias of 9-10days and the rest averaged 3.0±1.4days (range: 2-5days). Vaccinated groups Vinf and V2 had a significantly lower PRRSV shedding in oral fluids for at least the first 9days after the onset of the viremia compared to U, and shedding for V2 was even significantly lower (p<0.05) than shedding for Vinf. Our experimental design reproduced the worst-case scenario for evaluating the effect of vaccination and, under such conditions; it was still efficacious in slowering PRRSV transmission and decreasing the global viral load and particularly oral shedding.

Conocimientos, actitudes y prácticas acerca del dengue en un barrio de Asunción

La segunda epidemia del dengue clásico se inició en Paraguay a partir de febrero de 1999. En marzo de 2000 se establece un plan de emergencia interinstitucional por decreto del Poder Ejecutivo. Objetivo: determinar los conocimientos, actitudes y prácticas que poseen los pobladores del barrio San Pablo de la ciudad de Asunción acerca del control de los mosquitos y del dengue. Material y método: estudio observacional, descriptivo, aplicado a residentes adultos del barrio San Pablo, a través de una encuesta durante los meses de marzo y abril de 2000. El muestreo fue por conglomerados en una sola etapa. La selección de las manzanas se realizó en forma aleatoria para un n=187 viviendas, y una prevalencia esperada del 50%, con un nivel de confianza del 95%. Resultados: La prevalencia de la enfermedad fue del 41,2%. De este grupo, el 66,2% el diagnóstico fue médico y el 33,8% fue empírico. El 96,8% conocía la presencia actual de una epidemia de dengue y que los mosquitos podían transmitir enfermedades. El 89% no estaba organizada en su comunidad para luchar contra el dengue, el 61,8% cumplió con las medidas higiénicas de prevención y en el 36,2% no se constataron prácticas de medidas higiénicas de prevención en el hogar. Acerca del conocimiento para eliminar los criaderos de mosquitos, el 88,2% respondió adecuadamente y el 11,2% tuvo conocimiento incompleto sobre estas medidas higiénicas. Al ser indagados dónde depositaban sus huevos los mosquitos, el 70,1% respondió "en cualquier lugar donde esté un deposito de agua limpia y estancada" y el 18,7% "en los lugares donde se arrojan los desechos". El 24,6% de la población entrevistada supo que los mosquitos podían trasmitir tres enfermedades, el 85,1% incluyó al dengue en sus respuestas y el 14,4% desconoció las enfermedades trasmitidas por los mosquitos. Conclusiones: l) la población estudiada posee conocimientos adecuados con respecto a las características del dengue y el control de los mosquitos; 2) existe escasa participación en actividades comunitarias; 3) los conocimientos (información) adecuados no necesariamente derivan en prácticas preventivas.

A segunda epidemia do dengue clássico, iniciou-se no Paraguay a partir de fevereiro de 1999. Em março de 2000 se estabelece um plano de emêrgencia interinstitucional por decreto do Poder Executivo. Objetivo: determinar os conhecimentos, atitudes e práticas que possuem os cidadãos do barrio San Pablo da cidade de Asunción referente ao controle dos mosquitos e do dengue. Material e método: estudo observacional, descritivo aplicado a residentes adultos do bairro San Pablo, através de um questionário nos meses de março e abril de 2000. A amostra foi feita por conglomerado numa só etapa. A seleção dos quarteirões, realizou-se em forma aleatória para um n=187 lares e uma prevalência esperada de 50%, com um nível de confiança de 95%. Resultados: prevalência da doença foi de 41,2%. Deste grupo o 66,2% o diagnóstico foi médico e o 33,8% foi empírico. O 96,8% conhecia a presença atual de uma epidemia de dengue e que os mosquitos podiam trasmitir doenças. O 89% não estava organizado em sua comunidade para lutar contra o dengue; o 61,8% cumpriu com as medidas de higiene para prevenção e em um 36,2% não se constatou práticas de medidas de higiene para prevenção no lar. Referente ao conhecimento para eliminar os depósitos de mosquitos o 88,2% respondeu adequadamente e o 11,2% teve conhecimento incompleto sobre estas medidas de higiene. Ao perguntar onde depositavam seus ovos os mosquitos o 70,1% respondeu "em quelquer lugar onde houver um depósito de agua limpa e estancada" e o 18,7% "nos lugares onde se joga lixo". O 24,6% da população entrevistada soube que os mosquitos podíam trasmitir três doenças, o 85,1% incluiu o dengue em suas respostas e o 14,4% desconheceu as doenças trasmitidas pelos mosquitos. Conclusões: 1) a população estudada possui conhecimentos adequados referente às características do dengue e ao controle dos mosquitos; 2) existe pouca participação em atividades comunitárias; 3) os conhecimentos (informação) adequados não necessariamente resultam em práticas preventivas.

The second epidemic of dengue (classic form) began in Paraguay in february 1999. An interinstitutional emergency Plan was set up by two government decree in March 2000. Goal to assess the knowledge attitudes and practices to control dengue among the inhabitants of the San Pablo neighbourhood in Asunción. Material and method: descriptive study on adult residents of the San Pablo neighbourhood, through a poll during March and April 2000. The sampling was made in one step by conglomerates. Blocks were selected randomly for n=187 homes, with an expected prevalence of 50% and a confidence level of 95%. Results: prevalence of the disease was 41,2%. Physicians in 62% of the cases made diagnosis, while 33,8% were empirically diagnosed. 96,8% were aware of the current epidemic of dengue and that mosquitoes could transmit diseases. 89% were not community organized to fight against dengue. 61,8% observed the hygienic preventive measures, while 36,2% didn’t. On the knowledge about how to eradicate mosquitoes lay their eggs, 70,1% answered "wherever there are clean and still waters" and 18,7% "in dumping places". 24,6% knew that mosquitoes could transmit three diseases, 85,1% included dengue in their answers, while 14,4% didn’t know any disease transmitted by mosquitoes. Conclusions: 1) the surveyed population has adequate knowledge on dengue and mosquito control; 2) communal activities and participation are scarce; 3) adequate knowledge (information) doesn’t mean necessarily preventive practices implementation.

Conocimientos, actitudes y prácticas acerca del dengue en un barrio de Asunción / Knowledge, attitudes and practices about dengue in a neighborhood of Asunción

La segunda epidemia del dengue clásico se inició en Paraguay a partir de febrero de 1999. En marzo de 2000 se establece un plan de emergencia interinstitucional por decreto del poder ejecutivo. Objetivo: determinar los conocimientos, actitudes y prácticas que poseen los pobladores del barrio San Pablo de la ciudad de Asunción acerca del control de los mosquitos y del dengue. Material y Método: estudio observacional, descriptivo, aplicado a residentes adultos del barrio San Pablo, a través de una encuesta durante los meses de marzo y abril/2000. El muestreo fue por conglomerados en una sola etapa. La selección de las manzanas se realizó en forma aleatoria para un n=187 viviendas, y una prevalencia esperada del 50 porcientos, con un nivel de confianza del 95 porcientos. Resultados: la prevalencia de la enfermedad fue del 41.2 porcientos. De este grupo el 66.2 porcientos el diagnóstico fue médico y el 33.8 porcientos fue empírico. El 96.8 porcientos conocía la presencia actual de una epidemia de dengue y que los mosquitos podían transmitir enfermedades. El 89 porcientos no estaba organizada en su comunidad para luchar contra el dengue; el 61,8 cumplió con las medidas higiénicas de prevención en el hogar. Acerca del conocimientos para eliminar los criaderos de mosquitos el 88.2 porcientos respondió adecuadamente y el 11.2 porcientos tuvo conocimiento incopleto sobre estas medidas higiénicas. Al ser indagados dónde depositaban sus huevos los mosquitos el 70.1 respondió en cualqueir lugar donde esté un deposito de agua limpia y estancada y el 18.7 porcientos en los lugares donde se arrojan los desechos. El 24.6 porcientos de la población entrevistada supo que los mosquitos podían trasmitir tres enfermedades, el 85.1 porcientos incluyó al dengue en sus respuestas y el 14.4 porcientos desconoció las enfermedades trasmitidas por los mosquitos. Conclusión: la población estudiada posee conocimientos adecuados con respecto a las características del dengue y el control de los mosquitos. Existe escasa participación en actividades comunitarias. Los conocimientos (información) adecuados no necesariamente derivan en prácticas preventivas

[Juvenile xanthogranuloma in a flat xanthoma]. / Xantogranuloma juvenil sobre xantoma plano.

A case of juvenile xanthogranuloma located on a plane xanthoma plaque in the left flank of a seven months old child is reported. Histologically we observe a typical pattern of JXG in the center of the lesion and foamy cells exclusively around the capillary vessels in the peripheric areas of the lesion. We consider that the same etiopathogenic mechanisms implicated in the JXG will produce the clinical and histologic appearance of plane xanthoma around it.

[Cellular immunity in polymorphous light eruption]. / La inmunidad celular en la erupción polimorfa lumínica.

Lymphocytic-cell subsets (T total, T helper, T suppressor-cells) have been studied with Monoclonal Antibodies (OKT-3, OKT-4, OKT-8) in 21 patients with Polymorphous light Eruption in inactive phase and have been compared with 13 controls. The results shvon normal cell figures (T total, helper and suppressor). However, when observing the ratio between T helper cells and T suppressor cells, a slight decrease in this ratio is appreciated, which would correspond to a relative increase of suppressor cells. These results are similar to those obtained for the inactive S. L. E. (9).

[Lucio's leprosy]. / Lepra de Lucio.

A case of diffuse lepromatous leprosy with lepra reaction type II-Lucio's phenomenon-in a 24 years old male patient is reported. The histological examination of the necrotic lesions and of the apparently normal skin showed the presence of dense perivascular and perianexial lymphohystiocitic infiltrates with great quantities of bacilli. The first biopsy did not show a picture a leuccocytoclastic vasculitis but only areas of necrosis. The immunofluorescence studies revealed on direct examination complement deposits on vessel walls. The complement levels in blood were lowered and circulating inmunecomplexes were also detected. These data confirm the opinion that Lucio's phenomenon is caused by circulating inmunecomplexes fixed on dermal vessel walls causing skin necrotic lesions.