Hepatitis C virus (HCV) infects an estimated 170 million persons worldwide, and 2 million persons in Japan. HCV is a major cause of chronic liver diseases, especially hepatocarcinogenesis, and the number of patients with HCV-related hepatocellular carcinoma (HCC) is increasing worldwide as well as in Japan. Most patients with acute hepatitis C develop chronic hepatitis. Spontaneous disappearance of HCV in patients with type C chronic liver disease is uncommon, and it tends to progress to further advanced and more severe liver disease, ultimately to HCC over a period of 30 years in most cases. Chronic liver disease due to HCV infection is commonly associated with extrahepatic manifestation, for example cryoglobulinemia. Antiviral treatment for HCV infection with interferon alone during 24 weeks was associated with a low rate (less than 10%) of sustained virologic response (SVR), especially in patients infected with HCV genotype 1b and high HCV RNA concentration. However, combination therapy of interferon and ribavirin raises the SVR rate. More recently, pegylated interferon used for treatment of chronic hepatitis C resulted in a high SVR rate. These modalities of antiviral treatment will reduce HCC occurrence. So far, there is no HCV vaccine in spite of many efforts.

Rabbit antibodies to hemolymph antigens (102.5, 101, 100, 96, 88, 80, 64, 55, 43, 29, and 23 kDa) of Anopheles stephensi reduced fecundity as well as viability in An. stephensi. However, ingestion of these antibodies was not associated with a marked effect on the engorgement of mosquitoes but egg laying was significantly delayed. Antisera raised against hemolymph proteins were also used to identify cross reactive antigens/epitopes present in other tissues by Western blotting, as well as by in vivo ELISA. In addition, a significant reduction in oocyst development was also observed in An. stephensi mosquitoes that ingested anti-hemolymph antibodies along with Plasmodium vivax. The results confirmed the feasibility of targeting mosquito antigens as a novel anti-mosquito strategy, as well as confirmed the usefulness of such antigens for the development of a transmission-blocking vaccine.

To assess the prevalence of intestinal parasitic infections in human immunodeficiency virus (HIV)-seropositive subjects, fecal samples were collected from 120 HIV-seropositive patients and were analyzed for various intestinal parasites. Thirty-six patients (30%) were found to harbor an intestinal parasite. Cryptosporidium parvum was the most common (10.8%), followed by Giardia lamblia (8.3%). Cyclospora cayetanensis and Blastocystis hominis each were detected in 3.3% of the patients, while Isospora belli and Enterocytozoon bieneusi were each detected in 2.5% of the patients. The other parasites observed were Entamoeba histolytica/E. dispar in two cases and hookworm ova in one patient. Of the 36 patients who tested positive for intestinal parasites, 27 (75%) had diarrhea. The most common parasite, which was associated with diarrhea, was C. parvum. The present study highlights the importance of testing for intestinal parasites in patients who are HIV-positive, and emphasizes the necessity of increasing awareness among clinicians regarding the occurrence of these parasites in this population.

It is well known that herpes simplex virus (HSV) type 2 produces acute meningitis, while HSV type 2 rarely causes recurrent meningitis (Mollaret’s meningitis). We report the history of a 40-year-old patient with recurrent HSV type 2 meningitis (Mollaret’s meningitis). The patient had seven episodes of meningeal symptoms within a 7-year period. In the seventh episode, HSV type 2 DNA was confirmed by nested polymerase chain reaction (PCR) with the cerebrospinal fluid (CSF). A real-time quantitative PCR study of the first CSF sample detected 2,000 copies of the HSV genome, which rapidly disappeared following treatment with acyclovir. The present case may be the first case of HSV type 2 Mollaret’s meningitis to be documented in Japan. In our case, HSV serum antibody titers were at low levels during the whole course of the disease. The possible pathophysiology of this case is discussed.