The role of fruit bats in the transmission of pathogenic leptospires in Australia

Abstract

Although antileptospiral antibodies and leptospiral DNA have been detected in Australian fruit bats, the role of such bats as infectious hosts for the leptospires found in rodents and humans remains unconfirmed. A cohortdesign, replicated survey was recently conducted in Far North Queensland, Australia, to determine if the abundance and leptospiral status of rodents were affected by association with colonies of fruit bats (Pteropus conspicillatus spp.) via rodent contact with potentially infectious fruit-bat urine. In each of four study areas, a 'colony site' that included a fruit-bat colony and the land within 1500 m of the colony was compared with a 'control site' that held no fruit-bat colonies and was .2000 m from the nearest edge of the colony site. Rodents were surveyed, for a total of 2400 trap-nights, over six sampling sessions between September 2007 and September 2008. A low abundance of rodents but a high carriage of leptospires in the rodents present were found to be associated with proximity to a fruit-bat colony. For example, means of 0.4 and 2.3 fawn-footed melomys (Melomys cervinipes) were collected/100 trap-nights at sites with and without fruit-bat colonies, respectively (P,0.001), but the corresponding prevalences of leptospiral carriage were 100% and 3.6% (P,0.001). Such trends were consistent across all of the sampling sessions but not across all of the sampling sites.Leptospires were not isolated from fruit bats by culture, and the role of such bats in the transmission of leptospires to rodents cannot be confirmed. The data collected do, however, indicate the existence of a potential pathway for transmission of leptospires from fruit bats to rodents, via rodent contact with infectious fruit-bat urine. Fruit bats may possibly be involved in the ecology of leptospires (including emergent serovars), as disseminators of pathogens to rodent populations. Stringent quantitative risk analysis of the present and similar data, to explore their implications in terms of disease prevalence and wildlife population dynamics, is recommended.

Seroprevalence of Leptospira infection in bats roosting in human settlements in Morogoro municipality in Tanzania

“…These three serovars were previously reported in rodents and cattle from Morogoro (Machang'u et al, 2004;Mgode et al, 2006;Ahmed et al, 2006), suggesting that they are common serovars in this area. The high prevalence of local serovar Sokoine in bats suggest involvement of bats in transmission of leptospirosis to other animals in Morogoro confirming recent reports that bats are reservoirs of Leptospira and transmit these pathogens to other animals in Australia (Tulsiani et al, 2011).…”

“…The disease is also reported in bats in South America and Australia (Matthias et al, 2005;Bessa et al, 2010;Tulsiani et al, 2011). Studies of leptospirosis in bats and the extent to which they contribute to its transmission to humans and domestic animals in Tanzania and Africa in general are lacking.…”

Molecular epidemiology of pathogenic Leptospira spp. in the straw-colored fruit bat (Eidolon helvum) migrating to Zambia from the Democratic Republic of Congo

“…Contaminated urine has therefore been proposed as the potential transmission pathway of Leptospira spp. from fruit bats to rodents (Tulsiani et al, 2011). It is suggested, therefore, that E. helvum might be a candidate natural reservoir for Leptospira in Zambia.…”

“…A variety of pathogenic Leptospira spp. have been identified in bats worldwide (Bessa et al, 2010;Bunnell et al, 2000;Cox et al, 2005;Fennestad and Borg-Petersen, 1972;Harkin et al, 2014;Lagadec et al, 2012;Matthias et al, 2005;Tulsiani et al, 2011); however, little is known about the role of bats in the transmission of leptospirosis.…”

Similarities in Leptospira Serogroup and Species Distribution in Animals and Humans in the Indian Ocean Island of Mayotte

“…In addition, the grooming behavior of Pteropus, which consists in urinating and licking urine through the coat and wings, 16 favors direct contamination between bats. A recent study by Tulsiani and others 17 indicated the existence of a potential pathway for transmission of leptospires from pteropid fruit bats to rodents, by rodent contact with infected fruit bat urine. This is the second report of the presence of anti-Leptospira antibodies in free-ranging non-human primates, 18 however the extent of direct Leptospira transmission between nonhuman primates and humans is unknown.…”