Human herpesvirus 8 ([HHV-8], Kaposi's sarcoma-associated herpesvirus [KSHV]) is a novel human oncovirus classified as a gamma-herpesvirus. HHV-8 is associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL) and some cases of multicentric Castleman's disease (MCD). Antibodies against HHV-8 are detected in the sera of almost all KS patients, about 30% of HIV-infected homosexual males in the world and 1.4% of the Japanese population. In HHV-8-associated malignancies such as KS and PEL, HHV-8 latently infects these tumor cells. Unlike other viruses, HHV-8 encodes several human homologues including cytokines (IL-6, MIPs, IRFs) and regulatory proteins (cyclin D, G-protein coupled receptor [GPCR]). These proteins may play significant roles in the pathogenesis of HHV-8-associated diseases. It has been demonstrated in vitro that the functions of retinoblastoma and p53 proteins were inhibited by viral cyclin D and latency-associated nuclear antigen, respectively. Mice transgenic for GPCR have a KS-like region in the skin. These data suggest the full oncogenecity of HHV-8. On the other hand, many cells expressing lytic proteins are found in MCD tissues, suggesting that the pathogenesis of MCD is different from that of HHV-8-associated malignancies.

Jackfruit lectin (JFL) from Artocarpus heterophyllus has been found to exhibit inhibitory activity in vitro with a cytopathic effect towards herpes simplex virus type 2 (HSV-2), varicella-zoster virus (VZV), and cytomegalovirus (CMV). The 50% inhibitory dose values from plaque reduction assay (inactivation) were 2.5, 5, and 10 μg/ml of JFL for HSV-2, VZV, and CMV, respectively. Lymphocyte proliferation was significantly increased in the presence of the JFL in the concentration range of 2.5 to 50 μg/ml, but was reduced at 500 μg/ml. It was found that CD16⁺/CD56⁺ cells (natural killer cells) were induced among the primary lymphocyte subpopulations. The activity of natural killer (NK) cells was not affected by JFL in the concentration range of 5 to 500 μg/ml. These data suggest that JFL is mitogenic for NK lymphocyte (CD16⁺/CD56⁺) and also active against HSV-2, VZV, and CMV.

Antibodies against spotted fever group rickettsiae have been detected in blood samples of dogs and rodents obtained from selected areas in the Philippines. In this serosurvey, the positive percentage rates are 8.3% (11/132) in dogs and 12.2% (6/49) in rats. Positive results were read from samples tested with Rickettsia japonica antigen. No positive result was obtained in blood samples of rats and house mice using R. akari antigen. The findings of this study are the first to confirm the detection of spotted fever group rickettsial antibodies in the Philippines.

To investigate the prevalence of drug-resistant isolates of Salmonella Typhimurium in Aichi, Japan, we performed antimicrobial susceptibility tests for 148 isolates from healthy carriers, and from sporadic and outbreak cases of salmonellosis from 1980 to 1999. We found an increase in drug-resistant isolates from 56% (37/66) in the 1980s to 74% (61/82) in the 1990s due to increasing examples of four-, five-, and six-drug resistances. Of 98 resistant isolates in 1980 - 1999, 12 were identified as ampicillin (A)-, chloramphenicol (C)-, streptomycin (S)-, sulfonamide (Su)-, and tetracycline (T)-resistant S. Typhimurium (4 in the 1980s, 8 in the 1990s), whose pattern was identical to that of multi-drug-resistant S. Typhimurium definitive phage type 104 (DT104) which has been recently detected in various developed countries. Six-drug-resistance ACSSuTP (piperacillin), in which P was added to the core pattern of the ACSSuT, was also found in four isolates in the 1980s and seven in the 1990s. Another six-drug-resistant pattern, ACSSuTN (nalidixic acid), appeared in five isolates in the 1990s. These multi-drug-resistant isolates were predominately found in healthy carriers (21/28), suggesting that in Aichi the multi- (five- or six-) drug-resistant isolates of S. Typhimurium have existed in healthy carriers as well as in diarrhea patients in 1980 to 1999.