a total of 66 bats were caught at 3 locations in papua new guinea ( figure ; table a1 ) . they were anesthetized by using a combination of ketamine and medetomidine at doses similar to those stated in a previous study ( 12 ) . blood samples were held at room temperature for 2448 hours and then serum separated by using centrifugation as required . serum samples were held at 4c until they were shipped to the australian animal health laboratory . location and species of bats collected for study of henipavirus and rubulavirus antibodies in pteropid bats , papua new guinea , june 2008 . virus - specific antibodies were detected by using a variety of assays previously developed by our group at the australian animal health laboratory . for the henipaviruses , the luminex - based binding and inhibition assays ( 13 ) were used for initial screening , and positive samples were confirmed by virus neutralization test ( vnt ) . only those with positive results in all 3 assays elisa - positive samples were then confirmed by vnt against each virus . for viruses in the nbv species group , a mixture of purified recombinant sigma c proteins from nbv , pulau virus , melaka virus , and kampar virus was used as elisa antigen for initial screening . positive samples were then confirmed by western blot against each of the 4 recombinant proteins . for brov , initial screening was conducted by elisa using purified virion as antigen ; positive samples were confirmed by immunofluorescent antibody test on cells infected with brov . seroprevalence for hev was 50% ( 33/66 ) ; for niv , 55% ( 36/66 ) ; tiopv , 38% ( 25/66 ) ; menpv , 56% ( 37/66 ) ; nbv - like viruses , 17% ( 13/66 ) ; and brov , 6% ( 4/66 ) . the seroprevalence of the 2 types of paramyxoviruses , hev / niv at 55% and tiopv / menpv at 56% , is high . the most striking finding is the presence of antibodies to both groups of viruses in 36% ( 24/66 ) of the samples . considering that vnt is a more specific and less sensitive assay , compared with results of the study conducted in madgascar ( 14 ) , in which 1/427 serum samples contained vnt - positive antibodies to both henipavirus and tiopv , our finding suggests extremely different paramyxovirus infection dynamics in bats in papua new guinea . we anticipate that the use of pteropid immunoglobulin m  specific reagent ( currently in development in our group ) will clarify this question in the future . the positive rate for both groups of paramyxoviruses is much higher in p. conspicillatus bats ( spectacled flying fox ) from madang than dobsonia magna bats ( bare - backed fruit bat ) from bensbach . we believe this difference has more to do with the bat species than the geographic location . for henipaviruses , seroprevalence is slightly higher for niv than for hev , which is also consistent with the luminex inhibition assay showing a trend of slightly higher inhibition for niv than for hev ( data not shown ) . this higher seroprevalence may suggest that henipaviruses circulating in papua new guinea are more niv - like than hev - like . however , in the absence of genetic sequence data , serologic findings are inconclusive . in addition , for the 2 rubulaviruses , seroprevalence is higher for menpv than for tiopv . this finding is noteworthy because our previous data indicated a one - way cross - neutralization , with menpv antibodies failing to neutralize tiopv ( g. crameri and j. barr , unpub . the results from this study suggest either that the main strain of bat rubulavirus(es ) circulating in bats in papua new guinea is more closely related to menpv or that there are different strains circulating and the menpv - like are more dominant . although the overall seroprevalence for orthoreoviruses was much lower , the results nevertheless produced some useful information . first , the prevalence of 18% ( 2/11 ) of the nbv group viruses in d. magna bats at bensbach is not much different from the 20% ( 11/54 ) in p. conspicillatus bats at madang , indicating the nbv group of orthoreoviruses is present in bats of different species in papua new guinea . second , none of the 66 serum samples was positive for both nbv and brov , which supports our previous conclusion that brov is a new species in the genus orthoreovirus and that no significant cross - reactivity occurs between brov and orthoreoviruses of other species groups ( 11 ) . in this study , a serologic survey was conducted for 4 groups of viruses , 2 from the family paramyxoviridae and 2 from the genus orthoreovirus , family reoviridae . the surprising finding of a high prevalence of antibodies to both henipaviruses and tiopv / menpv in individual pteropid bats highlights the need for more structured studies to investigate the infection dynamics of zoonotic viruses in different bat populations across the world . it is not clear at this stage what factors are responsible for the vast difference in prevalence of antibodies to paramyxoviruses and orthoreoviruses . in the context of potential incursion of exotic bat viruses into australia , it is noteworthy that the bat rubulavirus(es ) circulating in papua new guinea are more menpv - like ( australia ) , whereas the papua new guinea henipavirus(es ) seem to be more niv - like ( asia ) . these findings are consistent with those in indonesia ( 15 ) and call for further molecular epidemiologic investigation to better assess the risk of niv entry into australia .
to determine seroprevalence of viruses in bats in papua new guinea , we sampled 66 bats at 3 locations . 
 we found a seroprevalence of 55% for henipavirus ( hendra or nipah virus ) and 56% for rubulavirus ( tioman or menangle virus ) . 
 notably , 36% of bats surveyed contained antibodies to both types of viruses , indicating concurrent or consecutive infection .