In 1957 Japan succeeded in eradicating rabies, which had been endemic since the 18th century, due to the registration and confinement of family dogs, the elimination of stray dogs, and the compulsory vaccination of dogs. At present, however, vaccination coverage of family dogs is far lower than the required level of 70%. The facilities that are presently able to investigate rabies are limited in number. In addition, few medical institutions keep rabies vaccine in stock or offer postexposure vaccination to travelers bitten by animals in rabies endemic areas. Moreover, rabies immunoglobulin (RIG) cannot be given to such individuals because RIG is not produced at present in Japan, nor is it authorized to be imported. To keep Japan free from any rabies deaths, an improvement in vaccination coverage among dogs and in the supply of postexposure prophylaxis is required, and the establishment of a rabies surveillance system is also considered to be essential.

Cholera toxin (CT) and Escherichia coli heat-labile toxin (LT) are not only the causative agents of diarrhea but are also strong mucosal adjuvants which enhance immune responses to mucosally coadministered bystander antigens. One of the most promising applications of these toxins would be as mucosal adjuvant of nasal influenza vaccine. In comparison to current inactivated vaccines, the nasal vaccine provides superior cross-protection by inducing production of cross-reacting anti-viral IgA antibodies in the respiratory tract even when the vaccine strain is different from the epidemic strain. On the use of the toxins as mucosal adjuvants in humans, toxicity and allergenicity of the toxins are problems which impinge on safety. To resolve these problems, various approaches have been attempted to produce less toxic and less allergenic CT (or LT) derivatives. We now propose the following standards for human use of safer CT (or LT) derivatives as an adjuvant of a nasal influenza vaccine. Thus, CT (or LT) derivatives can be administered intranasally together with a current inactivated influenza vaccine, provided they meet the following criteria. 1) A single dose of the derivatives, administered intranasally by spraying, should be around 100 μg/adult in a volume of less than 0.5 ml. 2) CT (or LT) derivatives should retain the properties of the native CT (or LT), i.e., the ability to augment secretory IgA and serum IgG Ab responses to viral surface glycoproteins, when administered intranasally together with an inactivated influenza vaccine. 3) CT (or LT) derivatives should not induce IgE Ab responses to the vaccine, as well as to the CT (or LT) itself. 4) The CT (or LT) should be nontoxic; the toxicity of the derivatives, as determined by the Y-1 adrenal cell assay, should not exceed 1/100 EC₅₀ of the native CT (or 1/1000 ECi of the native CT). 5) CT (or LT) derivatives should not cause serious disease in guinea pigs when administered intranasally or intraperitoneally at the dose used in humans (around 100 μg).

A study was undertaken to correlate the impact of housing and patterns of house construction on the vector density and transmission of filaria among the inhabitants of these houses. Three different types of houses in ecologically similar hamlets of Hariharpur village in Varanasi were selected for determining the density of Culex quinquefasciatus, the vector of Wuchereria bancrofti and its infectivity. The maximum per man hour density of the vector was recorded during March (31.66, 40.33 and 41.33) while minimum was recorded during June (1.3, 2.6 and 0.33) in all the three types of houses. Infection rate in the vectors collected from poorly constructed houses was observed during April, May, October and January of the following year, whereas in moderately constructed houses, infection was observed only in September and in the well constructed houses dissection results did not reveal any infection during the months of the study. Infectivity rate was observed to be 10.0% in moderately constructed houses (group B) during the month of September and 14.2% in poorly constructed houses (group C) during the month of October. Parasitological observations of the population showed a 12.2% microfilaria (mf) rate and 6.7% disease rate among the residents of poorly constructed houses, 5.8% mf rate and 2.9% disease rate among residents of moderately constructed houses. Among residents of well built houses (Group A), none were found to be positive with mf, but disease rate was observed to be 2.7%. Throughout the year the relative humidity was observed to be higher in the poorly constructed houses and ambient temperatures were found to be lower during the summer but higher during the winter than to those of the better constructed houses. The study made evident that the construction of houses plays an important role in the vector's resting preference, leading to a higher density in poorly constructed houses, thereby increasing the possibility of infection within them, and thus maintaining a higher potential for filarial transmission among its inhabitants.

The respective and combined effects of sodium chloride, ascorbic acid, citric acid, potassium sorbate, and Thymus vulgaris extract on the growth of Aeromonas caviae and Aeromonas sobria were investigated. Sodium chloride (3%) significantly reduced the growth and 4% NaCl inhibited growth of the tested strains. Ascorbic acid (0.1%), potassium sorbate (0.05%), and citric acid (0.03%) slightly inhibited growth. T. vulgaris extract (0.3%) greatly reduced the growth. Various combinations of these compounds prevented growth of the tested strains. A combination of NaCl (3%) and ascorbic acid (0.1 %), citric acid (0.03%) and potassium sorbate (0.05%), or citric acid (0.03%) and ascorbic acid (0.1%) inhibited growth of A. caviae and A. sobria. In fish homogenates, the addition of ascorbic acid (0.1%) and citric acid (0.03%) was the most effective combination tested.

This study described a program for and the results of a nationwide nucleic acid amplification testing (NAT) screening for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus type 1 (HIV-1) by multiplex reagent with a pooled system. After routine serological screening, this test was used in order to be in time for blood transfusions. The Japanese Red Cross currently supplies donated blood all over Japan for blood transfusion. As of January 2000, 2,140,207 units (5,093 pools) were tested by a pool size of 500 and 19 HBV DNA-positive cases and 8 HCV RNA-positive cases were found. Since February 2000, the pool size was switched to 50 and among 420,770 units (8,564 pools), 7 HBV DNA-positive cases and 1 HCV RNA-positive case were found. HIV RNA was not detected in any of the tested pools. Among the 26 HBV DNA positives, 22 were wild type; of these, 6 (23%) had hepatitis B surface antigen (HBsAg) that was undetectable by overnight enzyme immunoassay (EIA). Except for one case, in which coexisting antibody inhibited the immune reaction, all 17 cases that were followed later showed seroconversion. In 10 of these cases, HBV DNA disappeared below the level of detection and seroconversion of IgM anti-HBc and anti-HBc antibody occurred during the observation period. The remaining 4 cases were precore mutants and all had an undetectable level of HBsAg by EIA. Three cases did not show IgM anti-HBc seroconversion, which should be observed during the early stage of HBV infection. As for the HCV RNA, the following types were identified: 2 genotype II (1b), 3 genotype Ill (2a), and 4 ·genotype IV (2b). A weak anti-HCV positive reaction was observed in two cases and strong seroconversion in one case among 4 of the cases that were followed. Although it is not 100%, NAT narrows the window period in early-stage infection, resulting in an exponential reduction of the virus load that escapes serological screening tests for blood destined for blood transfusions. In the case of HBV, NAT screening detects HBV DNA in persistently infected individuals with extremely low levels of HBV antigen and antibody often observed in the case of HBV mutants.