The current understanding of the epidemiology of rabies in Argentina states that the vast majority of cases in the Northern region are associated with hematophagous bats. Very few cases of terrestrial rabies were also detected in the Northwestern (Salta and Jujuy) and Northeastern provinces (Formosa and Chaco) during 2010. The rest of the country has been considered terrestrial rabies-free since the early 1980s. This epidemiological situation makes it difficult to estimate the real impact of the insectivorous bat rabies in our country. In the north, very few cases have been detected probably masked by endemic bovine rabies. While in the center and south, the absence of terrestrial rabies has led to low level of awareness among general public, public health officials and health administrators. As a result, rabies associated with insectivorous bats and its potential consequent implications in public and animal health have been largely neglected in Argentina.
Our study reveals that the positivity rate of rabies in insectivorous bats received in the laboratory for analysis ranges from 3.1 to 5.4%. This proportion is comparable to other countries such as the United States (9–10%) where insectivorous bats are the only cause of concern for RABV surveillance systems, and other South American countries (Brazil (1.3%) and Chile (4.2%) 
. Fortunately, <1% of natural bat population have been shown to be infected 
. Thus, the risk of contracting rabies from insectivorous bats is low. However, evidence indicates that many of the human cases of rabies resulted from exposures to bats that were not recognized or reported 
. Consequently, prevention of human infection with bat rabies virus variants remains an important public health concern. On the other hand, emergence of rabies in terrestrial hosts after spillover from chiropteran reservoirs has been described but does not typically result in sustained transmission. However, if host switching of rabies virus variants occur, once established could be become enzootic in new reservoir species 
. Therefore, special attention should be paid to unusual epidemiological patterns of terrestrial rabies transmission in new geographic areas.
Antigenic characterization utilizing the eight monoclonal antibodies developed by the CDC is widely used in Latin America for RABV surveillance. However, in some instances, antigenic analysis is unable to identify RABV isolates obtained from several insectivorous bat species because these isolates produced atypical reaction patterns (unrelated to previously described virus reservoirs) 
. In those cases, partial genetic analysis of the viral nucleoprotein sequence allowed further characterization 
allowing the identification of lineages or genetic variants maintained by insectivorous bat species in an independent enzootic cycle. Indeed, in our work, we identified six RABV lineages that were specifically associated with specific bat species. Moreover, genetic analysis allowed us to differentiate some of the previously accepted antigenic variants in independent sublineages that appear to be related with different geographical or ecological niche behaviors. Tadarida brasiliensis
maintains circulation of its own antigenic (AgV4) with high degree of nucleotide and amino acid homogeneity in Argentina, Chile, Brazil and Uruguay. In contrast, analysis of RABV isolates recovered from Myotis
species showed a high antigenic diversity that could be related to the gregarious and non-migratory habits of these species 
. The elevated antigenic diversity of RABV sustained by Eptesicus
species can complicate definitive strain typing. This could be the case of the only Myotis associated strain from Chile, which was assigned to an apparent AgV3 using a reduced panel of eight N-MAbs by Yung et al. 
, but our genetic characterization revealed its real clustering into Myotis group.
All Argentinean isolates obtained from Histiotus montanus
, clustered in a single genetic group along with strains from Chile confirming that this species is its own the viral variant reservoir. There is little information about this species other than it lives a solitary life and migrates seasonally between Argentina and Chile 
. Although both countries are separated by the Andes Chain, an important natural barrier, low-lying passages of the mountain allow different species of bats and terrestrial mammals to move between the countries and thus spreading this viral variant 
Members of the genus Lasiurus typically are solitary and migratory bats. In our study, rabies samples from L. blossevillii, cinereus and ega were analyzed. A RABV isolate from Argentinean L.blossevillii bat was distant to others obtained from the Lasiurus genus but clustered with others from the same bat species from Brazil. Indeed, it yields a previously unrecognized genetic lineage circulating in Argentina.
On the other hand, antigenic and molecular analysis of rabies isolates from Lasiurus cinereus
confirmed that this species maintained its own antigenic (V6) and genetic variant as previously reported 
. Despite showing a wide geographical distribution (Canada to Argentina), RABV isolates from this species exhibited a high degree of nucleotide and amino acid homogeneity, which could be explained by its ability to transport its own specific strain during its long migration pattern. Two rabies samples of Chilean Lasiurus have been assigned to AgV4 (T.brasiliensis
reservoir) by Yung et al. 
, but our phylogenetic analysis showed that they grouped with Lasiurus strains (AgV6). This apparent discrepancy could be explained by the inadequate use of the N-Mabs panel which could lead to confusion between AgVs. The difference between both variants falls only in the reactivity with monoclonal C1. According to the N-Mabs manufacturer's instructions, all negative or diminished reactions should be confirmed by furthers tests of the samples with a 10-fold less-dilute antibody 
Molecular characterization of RABV isolates revealed that inter-species transmission is a relatively common event. Eleven (11.8%) of the 93 bat samples tested showed to be infected by a variant supported by another bat species. Cross-species transmission is facilitated by several types of species life-history traits and perhaps environmental variables structuring communities 
. In the case of Lasiurus
, these seem to have an important role in these events, since we have identified this variant nearly in all bat species studied. Although, L.cinereus
generally roosts in isolation, it has been observed occasional aggressive encounters at share roosts or during flight, which could promote viral transmission.
The findings of this study demonstrate the presence of rabies in several species of insectivorous bats throughout Argentina. Phylogenetic analysis of an extensive collection of rabies strains obtained from 14 species over a 17-year period shows complex epidemiological patterns characterized by the presence of multiple endemic cycles and relatively frequent inter-species transmission that are affected by several ecological aspects such as migration patterns, roosting and habitat. The establishment of viral variants associated with specific bat species can assist in the epidemiological investigation of cases of human rabies associated with bats and potential events spread to terrestrial mammals.