Modes of Seoul virus infections: persistency in newborn rats and transiency in adult rats

Abstract

To understand the mode of persistent infection of Seoul virus in rodents, we examined the distribution of the virus genome and antibody production in infected rats. When 1-day-old rats were inoculated with the KI-83-262 strain, the S segment of viral genome was detected in sera, clots, lungs and kidneys from 3 to 184 days post inoculation (d.p.i.) by nested reverse transcriptase PCR. On the other hand, when 7-week-old rats were infected with this virus, viral genome was detected only in the lungs from 3 to 50 d.p.i. The neutralizing antibody titers of rats inoculated at 1-day of age were higher than those of rats inoculated at 7 weeks of age. In both age groups, however, the IgG avidity of antibody increased along with the course of infection. We found that urban rats (Rattus norvegicus) infected early in life harbored the virus for more than 6 months.

Persistent hantavirus infections: characteristics and mechanisms

“…In one study, i.p. inoculation of one-day-old rats resulted in viral persistence for at least 184 days, whereas seven-weekold rats appeared to cure the infection after 50 days 21 . In the other study, using a different strain of Seoul virus, inoculation of newborn rats resulted in viral antigen persisting in tissues and organs for at least six weeks, whereas inoculation of threeweek-old rats did not result in any detectable viral antigen 22 .…”

“…38). This mechanism probably does not apply to hantaviruses, which replicate in many tissues and organs that are readily accessed by the host immune system, resulting in vigorous humoral responses 3,13,21,39 . Little is known about the hosts' cell-mediated immune responses during hantaviral persistence.…”

“…These changes could occur at many levels in the virus life cycle including transcription, translation, encapsidation, packaging or release from the cell. Support for the importance of these mechanisms is provided by studies of hantaviruses in their rodent reservoirs 3,4,11,21,26,28,37 . The infections were usually characterized by a transient viremia that peaked approximately seven to 14 days post-infection, followed by a prolonged period when virus was rarely detected in blood.…”

Mode of Infection of Hokkaido Virus (Genus Hantavirus) among Grey Red‐Backed Voles, Myodes rufocanus, in Hokkaido, Japan

“…All infected males captured at Nakagawa in October 2004 had a high level of antibody and viral RNA, suggesting that these animals had a persistent infection (11,23). Wild and laboratory-colonized bank voles (M. glareolus) acquire persistent PUUV infection, with antibodies, viral antigen, and infectious virus throughout their life time (59).…”

“…Wild and laboratory-colonized bank voles (M. glareolus) acquire persistent PUUV infection, with antibodies, viral antigen, and infectious virus throughout their life time (59). HTNV, SEOV, BCCV, and SNV can also persist in their hosts (18,19,23,31). During the summer mating season, M. rufocanus males may be more aggressive and have more opportunity to fight and become infected.…”