S. Edward Sulkin

Role of brown fat in pathogenesis of rabies in insectivorous bats (Tadarida b. mexicana.

Summary 1. Studies on the progression of peripherally inoculated rabies virus in Mexican free-tailed bats (Tadarida b. mexicana) suggest that the brown (hibernating) fat plays a significant role in the pathogenesis of rabies in this animal. 2. Brown fat may serve as a depot for the storage of virus in symptomless carriers of the rabies virus. 3. These studies provide another example of selective viral lipotropism.

Influence of Pregnancy and Cortisone Treatment on Brown Adipose Tissue in Bats.

Summary The interscapular brown adipose tissue of the bat (Tadarida b. mexicana) undergoes significant fluctuations in lipid content during the reproductive cycle. There is a progressive accumulation of lipid in the brown fat cells, beginning in early pregnancy and reaching a maximum level late in the gestation period. In contrast, during and shortly after parturition the brown adipose tissue is essentially deplete of lipid, while 2 weeks following delivery lipid can again be found in the brown fat cells. Cortisone treatment of non-gravid bats results in increased lipid accumulation in the brown fat similar to that observed in the pregnant animal. A gradual increase in weight of brown fat parallels lipid hypertrophy. The role of adrenal activity in directing alterations in the lipid content of the interscapular brown adipose tissue of bats during the reproductive cycle is discussed.

Interferon Production in Hamsters Experimentally Infected with Rabies Virus.

Summary The induction of interferon by rabies virus was studied in order to establish the status of this virus as an inducer of interferon in the cells it infects. Previous investigators, using in vitro systems, have been unable to demonstrate interferon production from cells infected with rabies virus, and this has caused some confusion among researchers working on rabies. However, using an in vivo system, we were able to isolate and characterize rabies induced interferon from several tissues. The brain, in which the virus reached its highest titer, also contained the largest amount of interferon, with the other levels of interferon corresponding to the centrifugal spread of rabies virus from the brain to the organs.

Relationship of Bat Salivary Gland Virus to St. Louis Encephalitis Group of Viruses.

Summary A virus recently isolated from the salivary glands of Mexican free-tailed bats (Tadarida mexicana) appears to be a new member of the JE-WN-SLE-MVE group of viruses. On the basis of the results of complement fixation tests it appears that the salivary gland virus of bats is more closely related to the West Nile virus than to other members of the group.

CAT-SCRATCH DISEASE.

Cat-scratch disease is a relatively common benign infection, presumably caused by a virus transmitted through the scratch of a cat. It is estimated that since 1951 more than 1000 cases have been recorded.The most important clinical manifestation is lymphadenitis. Diagnosis is based on positive results of a skin test with cat- scratch antigen; treatment includes antibiotic therapy and occasionally drainage by aspiration of suppurative nodes if they become fluctuant.