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Biomedical subjects

L Rampichini

Publications and source records attributed to L Rampichini.

16 recordsLinked to original sources

Experimental infection of calves with strains of Bovid herpesvirus-4.

Fourteen calves were inoculated intranasally (i.n.) with the viral isolates as follows: 5 with 85/BH 16TV, 1 with 85/BH 17TV, 1 with 85/BH 18TV, 2 with 85/BH 231TN and 5 with 85/BH 232TN. Strain 85/BH 16TV was the only one which caused overt respiratory-like disease in all inoculated calves. Onset of the disease was observed after 7-8 days of incubation and was characterized by fever, depression, nasal discharge and coughing. Virus was isolated from the nasal swabbings of calves obtained from post-infection day (PID) 2-10. The other viral strains did not cause any sign of disease although virus was isolated regularly from the nasal swabbings of the inoculated calves. Virus was recovered from central nervous system tissues of calves that were infected with 85/BH 16TV or 85/BH 232TN strains and were killed on PID 4 or 8. Virus was also isolated from other tissues, such as lymph node, nasal mucosa (PID 8), or lung (PID 4). It was speculated that the nervous system could be one of the target areas of the virus of the naturally occurring infection by BHV-4. This might indicate a possible role of the nervous system (site of latency?) in the pathogenesis of BHV-4 as is the case in certain herpesviral infections of man and the lower animals.

Animals↗

Reactivation in calves of latent infection by Bovid herpesvirus-4.

Nine calves, six of which had been infected with strain 85/BH 16TV and three with strain 85/BH 232TN of Bovid herpesvirus-4 (BHV-4), were treated with dexamethasone (DMS) three months after infection. DMS administration did not induce any clinical signs of disease, but BHV-4 was isolated from the nasal swabbings of all calves for a maximum of 8 days after the start of DMS treatment. The virus was also isolated from the nerve tissues, nasal mucosa, lymph nodes, lung and spleen of 4 calves that were killed at different stages (3, 5, 7 days) of the DMS treatment. Intranuclear inclusions associated with cellular shrinkage were found in the neural tissues of calves killed either 3 or 5 days after the start of DMS treatment. Unexpectedly, a latent infection by infectious bovine rhinotracheitis (IBR) virus was reactivated. The virus was isolated from the nasal swabbings of two calves and also from the brain, cerebellum and nasal mucosa of one calf killed 5 days after the start of DMS treatment.

Animals↗

A comparison of rotavirus strains of bovine, simian and porcine origin.

Three rotavirus strains of bovine, simian and porcine origin, respectively, were compared. The 3 viruses induced a classic rotaviral infection in newborn, conventionally reared calves. The cross neutralization tests revealed an antigenic identity of simian and porcine rotaviruses and a slight serologic correlation of these two viruses with the bovine rotavirus strain. However, in reciprocal cross protection tests carried out in calves, the simian rotavirus antiserum afforded weak protection to challenge infection with either the porcine or the bovine viruses. By contrast, the protective level of the bovine and the porcine rotavirus antisera was relatively high. It was speculated that the 81/36F bovine rotavirus could be considered, tentatively, as an antigenic reassortant rotavirus strain.

Animals↗

Reactivation of Bovid herpesvirus 1 and 2 and parainfluenza-3 virus in calves latently infected.

Two experiments were carried out to determine whether Bovid herpesvirus (BHV) 2 is able to induce a recurrent infection in experimentally infected calves. In the first experiment the stress induced by dexamethasone (DMS) treatment failed to reactivate the clinical condition or to induce shedding of BHV2. However, treatment with DMS reactivated a latent BHV1 infection in all calves previously inoculated with BHV2 and also in two noninoculated controls. Probably, because of the interference by BHV1 the study failed to resolve the question as to whether BHV2 could induce a recurrent infection. Consequently, a second experiment was performed using calves devoid of antibody to BHV1 and, therefore, probably, free of virus. By this study it was demonstrated that BHV2 can remain as a latent infection in cattle, which, when immunosuppressed as with DMS, can be reactivated. A finding of considerable interest in this experiment was that in 1 calf a concurrent piroplasma infection was also, unexpectedly, discovered. Recrudescence of latent BHV1 infection was induced by DMS treatment of calves possessing antibody to the virus. The infection once reactivated, was readily transmitted by contact to three other calves devoid of antibody to BHV1. In the same experiment Parainfluenza-3 (PI-3) virus was unexpectedly isolated from all calves. It was speculated that all calves were latently infected with PI-3 virus with concurrent infection by HBV1 acting as a stress inducing PI-3 reactivation. These studies seem to indicate that mixed infections could have an important role in the mechanism involved in the establishment of latent infections and viral reactivation.

Animals↗

Experimental infection and cross protection tests in calves with cytopathic strains of bovine rotavirus.

Four cytopathic strains (81/32F, 81/36F, 81/40F, 82/80F) of bovine rotavirus were shown to be pathogenic for conventionally reared newborn calves. Calves were infected orally, using 3 calves for each isolate. All became febrile, were depressed and diarrhoeic. Two calves, one of which in the group of those infected with 81/36F isolate, and the other infected with strain 81/40F, were killed when moribund. A 3rd calf from the 81/36F infected group, died. At necropsy localized lesions of the small intestines, which are considered to be typical of rotavirus infection, were found. Virus was consistently isolated from the fecal samples of the inoculated calves up to 13 days post-inoculation. It was speculated that some differences existed in the virulence of the bovine rotaviruses tested. The cross protection tests revealed that 1 strain (81/36F) might be antigenically more complex than the others.

Animals↗

Reactivation in calves of Bovid herpesvirus 2 latent infection.

Seven calves which had recovered from an experimentally induced infection with Bovid herpesvirus 2 (BHV 2) were subjected to a course of dexamethasone (DMS) treatment six months later. BHV 2 was recovered from nasal swabs obtained from each calf 11 days after the start of DMS treatment. The virus was also isolated from the skin, nervous system tissue and lymph nodes of a calf killed 11 days after the start of DMS treatment in which a concurrent piroplasma infection was also, unexpectedly, discovered. It is suggested that the skin and nervous system are possible anatomical sites for the latency of BHV 2 in the host.

Animals↗

Attempts to reactivate bovid herpesvirus-2 in experimentally infected calves.

A study was carried out to determine whether bovid herpesvirus-2 (BHV-2) is able to induce a recurrent infection in experimentally infected calves. Twelve calves infected with the virus were treated with dexamethasone (DMS) beginning 69 days after the infection, ie, several weeks after the animals had recovered from the disease and were negative for BHV-2. The stress induced by DMS treatment failed to reactivate the clinical condition or to induce shedding of BHV-2. However, treatment with DMS reactivated a latent infectious bovine rhinotracheitis (IBR) virus infection in all calves previously inoculated with BHV-2, and also in 2 noninoculated controls. The reactivation of IBR virus occurred without any clinical evidence of the disease, but the virus was isolated from nasal and pharyngeal swabbings and from the organs. A proliferative ganglionitis of the trigeminal ganglion was also observed. Because of the interference by IBR virus, this study did not resolve the question as to whether BHV-2 can induce a recurrent infection.

Animals↗

A study of bovid herpesvirus 2 infection in calves inoculated intradermally or intranasally.

Bovid herpesvirus 2 infection was studied in calves exposed to the virus by intradermal inoculation of the skin of the left cheek or by nasal spray. In either case a localised infection developed and virus replication was shown to occur mostly in the tissues of its primary localisation, i.e. the skin of the left cheek or the nasal mucosa. There were neither secondary lesions, except at the site of virus injection, nor any serious systemic involvement on the part of the animals. The virus was also recovered from some areas of the skin (right cheek, perineum and scrotum) that were free of macroscopic lesions; moreover, intranuclear inclusions were found in several tissues of the nervous system (brain, superior cervical, stellate and Gasserian ganglia) which did not show any signs of inflammatory or degenerative changes. These findings suggest that the skin and the nervous system play an important role in the naturally-occurring disease since they could be the sites where the virus is maintained latently in the host.

Administration, Intranasal↗

Distribution of Bovid herpesvirus 2 in calves inoculated intravenously.

The behavior of Bovid herpesvirus 2 in the skin, lymph nodes, and nervous system of calves injected intravenously with the virus was studied. After a latent phase that lasted up to 40 hours after inoculation, the virus produced a systemic infection which was characterized by primary localization of virus in the skin, lymph nodes, and nervous system. Between postinoculation days 7 and 12, the infection tended to persist in the skin only. The finding of intranuclear inclusions in the pyramidal cells of the cerebral cortex and in the neurons of the superior cervical and stellate ganglia supports the hypothesis that the virus might utilize the structures of the nervous system for its replicative cycle in the calf.

Animals↗

Epidemiologic study on enzootic bovine leukemia in Italy.

The results obtained from serologic and hematologic investigations conducted on 1.124 cattle belonging to 14 herds located in Central Italy are reported. The results demonstrate a considerable number of animals with antibodies to Bovine Leukemia Virus (BLV) and/or lymphocytosis, coming from Friesian herds with or without history of leucosis. Furthermore it is demonstrated the absence of animals with circulating antibodies to BLV in herds made up of the Chianina breed even with a herd history of leucosis.

Animals↗

[Bovine enzootic leukemia and study of c-type particles in a cow with acute lymphatic leukemia and in cattle of the same herd with persistent lymphocytosis].

A case of acute lymphatic leukemia in a 7-month-pregnant Italian Friesian cow, aged about 6 years and belonging to a small dairy herd of 11 cows is described. Hematologic, histopatologic and ultrastructural examinations were performed, the ultrastructural studies were confined to the lymphnodes, thymus and buffy-coat cultures from peripheral blood. The remaining animals were subjected to hematologic examination and electron microscopy examination of buffy-coat cultures from peripheral blood. C-type particles were found in phytohemagglutinin (PHA)-treated and untreated buffy-coat cultures from the leukemic cow and from the animals with persistent lymphocytosis. C-type particles were also found in milk samples from 3 cows with persistent lymphocytosis.

Animals↗

Epidemiologic study on enzootic bovine leukemia using serologic tests and hematologic examinations.

In order to find suitable diagnostic procedures to use in an epidemiologic survey for the detection of animals infected with the bovine leukemia virus (BLV), the authors conducted an investigation on 262 Friesian dairy cattle. The results of hematologic, serologic, and electron microscopic examinations are reported. Evaluation of the results demonstrated the validity of the immunodiffusion and immunofluorescence tests and the opportunity for their use in conjunction with examination of the blood picture. From the data reported it would appear useful to extend the investigation to the herds without history of lymphosarcoma.

Animals↗

Preliminary studies on the diffusion of bovid herpesvirus 2 in experimentally infected calves.

This preliminary study on the diffusion of the Bovid herpesvirus 2 (BHV2) in calves inoculated intravenously, allowed to identify the target organs of the virus. In particular, in the first phase of the infection, i.e. post infection day (PID) 2, the virus resulted extensively widespread in the body of the calf, whereas in a subsequent phase, PID6, the virus was recovered only from the skin, the lymph nodes and the nervous system. Finally virus was not recovered in any of the tissues obtained from the calf killed at PID 12. Based on the results it might be speculated that, under the experimental conditions of these tests, the infection of cattle by BHV2 develops through two stages. The first stage would be characterized by a systemic condition in that the virus is present in the whole organism; the second stage which follows, consists in a localized infection, the virus being present only in some districts of the organism (skin, lymph nodes, nervous system) which could be considered as the definitive target sites for virus replication.

Animals↗