The effects of dietary T-2 toxin on acute herpes simplex virus type 1 infection in mice

Young male white Swiss mice were fed control diet or diet supplemented with 20 or 10 parts per million (ppm) of T-2 toxin for two or three weeks. These mice then were inoculated with herpes simplex virus type 1 (HSV-1) (9.6 x 10(6) plaque forming units) intraperitoneally. To compare the effects of T-2 toxin against a known immunosuppressive drug, cyclophosphamide was injected intraperitoneally at 150 mg/kg, 24 hours after treatment with HSV-1, into mice fed the control diet. Mice were necropsied and tissues were collected for microscopic and virologic examination. White Swiss mice which consumed a daily diet containing 20 ppm of T-2 toxin for two or three weeks were highly susceptible to HSV-1 infection and 27 of 36 (75%) died as a result of extensive hepatic and adrenal necrosis. Although HSV-1 was isolated from livers and brains of mice fed 20 ppm of T-2 toxin for two or three weeks, there was little or no inflammatory response found in the adrenals, livers, spinal cords, brains, or ganglia. The necrotizing encephalomyelitis observed in control mice was absent. High levels of dietary T-2 toxin appeared to be more immunosuppressive than cyclophosphamide because only one mouse died after treatment with HSV-1 and cyclophosphamide. Mice treated with cyclophosphamide had changes in brain, spinal cord, spleens, thymus, and bone marrow which were similar to those fed 20 ppm of T-2 toxin and infected with HSV-1, however, liver lesions were much less severe. HSV-1-infected mice on a diet with 10 ppm T-2 toxin had lesions of intermediate severity when compared with HSV-1-infected mice fed a diet with 20 ppm T-2 toxin and HSV-1-infected mice on control diets. Necrosis was less extensive in the livers and adrenals. The infrequent isolation of virus from liver and brain was consistent with the lack of intranuclear inclusion bodies and a more marked inflammatory response. Ten ppm of dietary T-2 toxin only depressed bone marrow and splenic red pulp to a mild or moderate degree. This may have enhanced the necrotizing encephalomyelitis observed in mice killed on days 6 and 8 after HSV-1 infection. Liver lesions were mild and those of the adrenals were moderate in mice fed control diet. The rare isolation of HSV-1 from the liver and brain and the findings of a moderate to severe necrotizing encephalomyelitis in these mice was consistent with an essentially functional immune system.

Host genetics and the behavioral sequelae to herpes encephalitis in mice

The effects of intracerebral infection with herpes simplex virus on the subsequent behavior of two strains of mice were examined. Infected Nya:NYLAR mice were hyperactive and did not show any deficits in the acquisition or reversal of a spatial learning task. In contrast, infected Nya:(SW) mice were hypoactive and made more errors than controls during both phases of the learning tasks. These differences in the nature of the sequelae to infection were related to an overall higher virus titer in the brains of Nya:(SW) mice, an effect particularly marked in the cerebral hemispheres. The results suggest that herpes encephalitis may produce a variety of behavioral syndromes, depending in part on the genetic background of the host. The relevance of these findings to clinical disorders produced by viral infection is discussed.

Delayed wound healing in mice associated with viral alteration of macrophages

Mice acutely and chronically infected with Sendai virus had impaired healing of incisional wounds. This impairment could be overcome by instilling the macrophage-stimulators zymosan and glucan into full-thickness incised wounds, whereas levamisole, an immunomodulator, had no effect on tensile strength of these wounds (breaking strengths). Another commonly occurring murine virus, murine hepatitis virus, also reduced wound tensile strength in infected mice. However, the murine strain of herpes simplex virus, type 1, which caused greater morbidity, did not reduce tensile strength. Although measurements of wound length and wound breaking strength clearly showed the adverse effect of viral infection, histologic evaluation of wounds did not consistently reveal a similar change in composition of wound "cell aggregation centers" for mice infected with the Sendai and murine hepatitis viruses.

Absence of antibodies against SV5, measles and herpes simplex in indoor colony-bred cynomolgus monkeys

One hundred and eighty-one cynomolgus monkeys born and raised at Tsukuba Primate Center for Medical Science (TPC) were serologically examined for the presence of antibodies against simian virus 5, measles virus and herpes simplex virus. All of them were virtually free from infections with these viruses, whereas wild-originated breeders kept at TPC were highly positive for these antibodies. These results can be regarded as demonstrating that an indoor breeding system such as TPC's is useful and valuable for producing nonhuman primates of good quality being completely free from those viral infections.

Serological survey for SV5, measles and herpes simplex infections in newly-imported cynomolgus monkeys

On 592 cynomolgus monkeys of newly-imported 14 different groups, sero-epidemiological follow-up surveys of natural infections with SV5, measles (MV) and herpes simplex (HSV) were conducted both at the time of arrival and at the end of the 9-week quarantine period at Tsukuba Primate Center for Medical Science (TPC). At the time of arrival, the positive rate of antibodies against these viruses greatly varied with different countries of origin. As regards SV5, the positive rate ranged widely from 0 to 94.9% among different import-groups, being markedly low in the Philippine monkey groups. The positive rate of MV antibody was generally very high, varying from 11.1 to 78.2% in almost all import-groups except two groups from Indonesia in which no positive case was detected. Concerning HSV, every import-group had a very high positive rate though the average antibody titer was not so high. Generally, the positive rates of SV5 and MV markedly increased by the end of quarantine period. Especially, MV positive rate reached 100% in almost all of the import-groups. However, two Indonesian groups showed no increase of SV5 and MV positive rates during the quarantine period. No increase of SV5 positive rate was detected either with any of three Philippine groups. As for HSV, the positive rate remained unchanged or rather decreased during the quarantine period in almost all groups except two Indonesian groups having shown a significant increase.

Spontaneous generalized Herpesvirus hominis infection of a lowland gorilla (Gorilla gorilla gorilla)

A 13-day-old lowland gorilla died from a generalized herpesvirus infection shortly after the onset of clinical signs. The pathologic-anatomical findings were compatible with those described for generalized herpes simplex infection in the human neonate. Electron microscopic examination of lung tissue revealed the presence of herpesvirus which was identified with the fluorescent antibody technique as Herpes simplex virus type I. Tests with related sera of the herpes group (varicella, herpesvirus-B) revealed no specific immunoflourescence.

Natural genital herpesvirus hominis infection in chimpanzees (Pan troglodytes and Pan paniscus)

Type 2 Herpesvirus hominis was isolated from pustulovesicular lesions on the external genitalia of two chimpanzees. Histopathologic examination of biopsy specimens from both animals revealed typical herpetic changes which included necrosis, superficial ulceration acute inflammatory cell infiltration, multinucleated syncytial giant cells, and intranuclear inclusions. Large numbers of herpes-type viruses were demonstrated by electron microscopy in biopsy specimens from both animals. Serologic studies also demonstrated infection of these animals with Herpesvirus hominis.

Necrotizing encephalitis in skunks caused by Herpes simplex virus

Herpes simplex virus was isolated from the brain of a wild skunk (Mephitis mephitis) which had clinical neurological disease. In the brain of this skunk and in brain of skunks inoculated intracerebrally, there were areas of necrosis in the grey matter of the cerebral cortex and to a lesser extent in the brain stem. Intranuclear inclusions occurred in neurons and glial cells with vascular cuffing by mononuclear cells and a few neutrophils. Skunks inoculated intravenously had extensive focal necrosis in the liver and adrenal glands.

Feline herpes virus infection

Ten cases of naturally occurring dendritic keratitis (feline herpes keratitis), which are manifestations of the disease commonly known as feline viral rhinotracheitis, have been identified in domestic cats in San Fancisco. Neonatal, juvenile, and adult forms of the disease are described and their treatment is discussed.