Viruses isolated from bats in Japan

Area of Science:

• Virology
• Zoonotic Diseases
• Mammalian Virology

Background:

• Bats are known reservoirs for diverse viruses, posing potential zoonotic risks.
• Understanding viral diversity in bat populations is crucial for public health surveillance.
• Previous studies have indicated the presence of various viruses in Japanese bat populations.

Purpose of the Study:

• To isolate and characterize novel viruses from bats in Japan.
• To investigate the pathogenicity and physicochemical properties of isolated bat viruses.
• To determine the serological relationship of these isolates to known flaviviruses, including Japanese encephalitis virus (JEV).

Main Methods:

• Virus isolation from bat blood, spleen, liver, and kidneys.
• Pathogenicity testing in suckling and adult mice.
• Filtration studies using Millipore filters (0.22 micron).
• Physicochemical property analysis (ether and sodium deoxycholate resistance).
• Serological assays including haemagglutination inhibition (HI) and complement fixation (CF) tests.

Main Results:

• Nine viruses were isolated from 838 bats (1.1% isolation rate).
• Two isolates from *Vespertilio supernas* were lethal to suckling mice.
• Seven isolates were filtrable, pathogenic for suckling mice, and exhibited varying resistance to ether and sodium deoxycholate.
• Complement fixing activity was detected in four strains, suggesting potential antigenic relationships.
• Serological analysis indicated that some isolates were distinct flaviviruses, unrelated to Japanese encephalitis virus (JEV).
• 1-10% of bat sera contained antibodies against JEV.

Conclusions:

• Japanese bats harbor a diversity of potentially pathogenic viruses.
• Some isolated viruses represent novel flaviviruses distinct from JEV.
• Further research is warranted to assess the zoonotic potential and public health implications of these bat-derived viruses.