Evaluation of immuno efficiency of hemorrhagic septicemia vaccine strain (vaccine seed)

<p><b>OBJECTIVE</b>To compared seed culture of hemorrhagic septicemia (HS) bacteria which was used to produce vaccine for its antibody induction efficiency before and after passaging in natural host (calf) using laboratory animals.</p><p><b>METHODS</b>Serial dilution of virulent bacteria was injected in to mice which were immunized with HS vaccine which was obtained from seed bacteria before and after back passaged in calf. Ratio of survived and dead was calculated by Reed-Meunch hypothesis and the LD50 value for each vaccine trial groups were calculated.</p><p><b>RESULTS</b>The immunological study revealed that vaccine prepared from back passaged seed culture showed greater improvement in its immunopotency than seed vaccine (before back passage). Around 200 mice were used to study the immuno efficiency of vaccine. Each mouse was from the same source, which were free from the Pastuerella infection previous to expose to trial infection. The same broth culture of HS was used to induce infection in mice in both trials (vaccine before back passage and vaccine after back passage). The 0.2 mL of broth dilution from 10(-1) to 10(-10) was used, as dilution increases, death rate decreases. It indicates the minimum load of bacterium is required to induced infection.</p><p><b>CONCLUSIONS</b>Obtained results revealed that back passaged vaccine seed HS bacteria in its natural host had provided better immune efficiency to the culture than laboratory stock culture, and this findings recommended that regular annual back passage was mandatory for the vaccine seed culture of Pastuerella multocida bacteria for better establishment of immune potent vaccines.</p>

Natural invertebrate hosts of iridoviruses (Iridoviridae) / Hospederos naturales de los iridovirus de invertebrados

Invertebrate iridescent viruses (IIVs) are icosahedral DNA viruses that infect invertebrates, mainly insects and terrestrial isopods, in damp and aquatic habitats. Exhaustive searches of databases resulted in the identification of 79 articles reporting 108 invertebrate species naturally infected by confirmed or putative iridoviruses. Of these, 103 (95%) were arthropods and the remainder were molluscs, an annelid worm and a nematode. Nine species were from marine habitats. Of the 99 non-marine species, 49 were from terrestrial habitats and 50 were aquatic, especially the aquatic stages of Diptera (44 species). The abundance of records from species of Aedes,Ochlerotatus and Psorophora contrasts markedly with a paucity of records from species of Anopheles,Culex and Culiseta. Records from terrestrial isopods are numerous (19 species), although the diversity of IIVs that infect them is mostly unstudied. IIV infections have been reported from every continent, except Antarctica, but there are few records from Africa, southern Asia and Latin America. Most reports describe patent IIV infections as rare whereas inapparent (covert) infection may be common in certain species. The relationship between particle size and iridescent colour of the host is found to be consistent with optical theory in the great majority of cases. Only 24 reported IIVs from insect hosts have partial characterization data and only two have been subjected to complete genome sequencing. I show that the rate of publication on IIVs has slowed from 1990 to the present, and I draw a number of conclusions and suggestions from the host list and make recommendations for future research efforts.

Los virus iridiscentes de invertebrados (VIIs) son virus icosaedrales de ADN que infectan a invertebrados, principalmente insectos e isópodos terrestres en hábitats húmedos y acuáticos. Búsquedas extensivas de bases de datos resultaron en la identificación de 79 artículos científicos, los cuales reportaron 108 especies de invertebrados infectados naturalmente por iridovirus. De estos, 103 (95%) fueron artrópodos y los otros fueron moluscos, un anélido y un nematodo. Nueve especies fueron de hábitats marinos. De las 99 especies no marinas, 49 fueron terrestres y 50 fueron acuáticas, especialmente los estadios acuáticos de dípteros (44 especies). La abundancia de infecciones en especies de Aedes,Ochlerotatus y Psorophora se contrasta marcadamente con la escasez de casos en especies de Anopheles,Culex y Culiseta. Reportes de infecciones de los isópodos terrestres son numerosos (19 especies), aunque la diversidad de los VII que los infectan es desconocida. Se han reportado infecciones por VIIs de todos los continentes, excepto Antártica, pero se notan pocos ejemplos de África, Asia y Latinoamérica. La mayoría de los artículos señala que las infecciones patentes son poco comunes, mientras que las infecciones enmascaradas (subletales) pueden ser comunes en algunas especies. La relación entre el tamaño de la partícula y el color iridiscente concuerda con la teoría óptica en casi todos los casos. Veinticuatro de los VIIs de insectos han sido caracterizados parcialmente y solo dos de éstos han sido secuenciados completamente. Demuestro que el ritmo de publicación sobre los VIIs ha disminuido en los últimos 15 años, señalo varias conclusiones y sugerencias de la lista de especies de huéspedes y presento algunas recomendaciones para la investigación futura con este grupo de patógenos.

Distrilbution and epidemic of bird influenza virus in its natural hosts / 医学研究生学报

Birds,especially wild waterfowls,are a natural reservoir of influenza virus,though poultry,mammalians and even human beings are also thought to be the potential hosts.Influenza virus can be classified into subtypes according to the characteristics of the nucleocapsid protein and membrane protein,each subtype with its own most adaptable host,so called host range restriction.However,the outbreak and spreading of influenza in different species has aroused increasing attention since its disastrous consequence on the ecological system of the earth.Large-scale epidemic survey,prediction of possible mutation of the virus,development and application of vaccines are key actions to be taken to prevent the pandemic of influenza.This article offers an overview of the ecology of influenza virus,features of recent great outbreaks of avian influenza,and relevant issues of concern.

Restoration of Adriamycin and Vincristine Dependent Tumoricidal Activity by Interferon in Mice with Implanted Tumor Cells

The survival of implanted tumor cells in mice which had been treated with interferon in combination with either adriamycin or vincristine was evaluated. While the majority of tumor cells implanted into normal mice failed to survive (52.1 to 63.5%), most of those implanted into mice which had been pretreated with either adriamycin or vincristine survived. If the mice were secondarily treated with interferon, the ability of adriamycin or vincristine to inhibit the survival of implanted tumor cells was restored within 24 hours. Restoration of tumoricidal activity by interferon treatment was more evident in the adriamycin pretreated mice. Peritoneal macrophages isolated from mice pretreated with both interferon and adriamycin had an increased tumoricidal activity, when compared with those isolated from mice treated with adriamycin alone. This interferon dependent enhancement of tumoricidal activity was comparable with that obtained by treating mice with lymphokines a product of Con A treated lymphocytes isolated from BCG treated mice. These results suggested that both adriamycin and vincristine may damage the macrophages required for the natural host defense mechanism and allow the implanted tumor cells to survive. Interferon may, however, protect the macrophages from drug induced damage.