Tacaribe virus causes fatal infection of an ostensible reservoir host, the Jamaican fruit bat

Abstract

Tacaribe virus (TCRV) was first isolated from 11 Artibeus species bats captured in Trinidad in the 1950s during a rabies virus surveillance program. Despite significant effort, no evidence of infection of other mammals, mostly rodents, was found, suggesting that no other vertebrates harbored TCRV. For this reason, it was hypothesized that TCRV was naturally hosted by artibeus bats. This is in stark contrast to other arenaviruses with known hosts, all of which are rodents. To examine this hypothesis, we conducted experimental infections of Jamaican fruit bats (Artibeus jamaicensis) to determine whether they could be persistently infected without substantial pathology. We subcutaneously or intranasally infected bats with TCRV strain TRVL-11573, the only remaining strain of TCRV, and found that low-dose (10(4) 50% tissue culture infective dose [TCID(50)]) inoculations resulted in asymptomatic and apathogenic infection and virus clearance, while high-dose (10(6) TCID(50)) inoculations caused substantial morbidity and mortality as early as 10 days postinfection. Uninoculated cage mates failed to seroconvert, and viral RNA was not detected in their tissues, suggesting that transmission did not occur. Together, these data suggest that A. jamaicensis bats may not be a reservoir host for TCRV.

Fig 1

Tacaribe virus is lethal to Jamaican fruit bats. Two bats were euthanized on days 4 and 8 p.i. (DPI) and were asymptomatic. However, on day 10, one bat was found dead, and during the next 8 days, the remaining bats died or were euthanized for humane reasons.

Fig 2

Weight loss with lethal Tacaribe virus infection. Weight loss was recorded for the 10⁶ s.c., 10⁶ i.n., 10⁴ s.c., and 10⁴ i.n. groups. Bats that survived had minimal weight fluctuations during the 45-day experiment. However, bats that became moribund (674, 676, and 677) each had weight decline prior to euthanasia.

Fig 3

Histologic studies of tissues from TCRV-infected bats in the first experiment. (A) Bat 712 with encephalitis and multifocal gliosis. (B) Bat 712 with lymphocytic meningitis. (C) Bat 712 with interstitial pneumonia. (D) Bat 718 with focal hepatic necrosis.