Eaton (2001) notes that about 40 viruses have been isolated from bats during the last 40 years, and serological studies suggest that bats are infected by several dozen more. Members of the Rhabdoviridae, Flaviviridae, Bunyaviridae, Alphaviridae, Reoviridae, Arenaviridae, and Herpesviridae families have all been demonstrated to parasitise bats. Closely related to rabies, the Australian bat lyssavirus was identified in 1996 in clinically ill and asymptomatic P. poliocephalus and has infected humans, P. alecto, P. scapulatus, Saccolaimus flaviventris, and Nyctophilus spp. (Hall and Richards, 2000, Field et al., 1999).
Eight paramyxoviruses have been identified in megachiroptera. Five do not appear to be zoonotic, though two have not been characterised. Pavri et al. (1971) isolated a new subtype of parainfluenza virus type 2 from Rousettus leschenaulti in India. Mapuera virus of the genus Rubulavirus was found in Sturnira lilium in Brazil (Henderson et al., 1995). Menangle virus (Philbey et al., 1998) infects at least three Australian pteropids. Lam and Chua isolated Tioman virus from the urine of P. hypomelanus as well as a third virus that they have not yet characterised. Another new virus, probably a Henipavirus, was identified by enzyme immunoassay and confirmed by serum netrualization test in P. lylei in Cambodia. Nipah virus probably infects at least five bat species and Hendra virus at least four.
Non-viral endoparasites of Pteropus spp. include Hepatocystis pteropi,Trypanosoma pteropi and Hymenolepis spp., Filaria spp., and the ascaridoid nematode Toxocara pteropodis. T. pteropodis is transferred horizontally through feces. Adult parasites are found only in the intestines of suckling young bats, which excrete the eggs in their feces. The eggs become infective in 10 days and are ingested by adult bats consuming foliage in camps. Larval parasites live in the liver of male hosts and pass through the mammary glands of lactating female hosts (Nelson, 1989).
Bat ectoparasites include members of families Laelipidae, Nycteribiidae, and less commonly Spinturnicidae. Cyclopodia albertisii is particularly widespread among pteropids (Nelson, 1989). Makifilaria inderi (Onchoceridae) has been found in P. hypomelanus (Bonaccorso, 1998).
There are reports of increasing birth abnormalities in Australian pteropids, especially P. alecto. Mass abortions have been documented in P. poliocephalus camps in Beenleigh (1978) and Brisbane (1983); in the Beenleigh camp, several thousand females out of approximately 12,000 lost their fetuses (Hall and Richards, 2000).
Author: S. Cobey.