Table 1

Description of risk factors for Hendra virus serostatus included in univariate analysis. (Data were collected from 664 LRFF sampled over five field seasons between November 2004 and March 2006.)

variabledescriptionno. of animals
sex
male321
female343
age
 0–1 montha pup that is dependent on its mother, usually up to the age of three months; as we were sampling during the peak birthing time, these animals were all less than a month old8
 3 monthsjuveniles sampled in July; the pup is too large to be carried by the mother, but has not yet reached full size; mandibular third molars have not fully erupted; permanent dentition still fragile with slight pinkish tone (appears almost transparent in places)50
 6 monthsjuveniles sampled in November; the pup is independent, but has not yet reached full size; all teeth have erupted and have reached their full length; teeth show no signs of wear (cusps are sharp), but slight (diet dependent) lateral staining is possible64
 pre-breedingan animal that is full size but not sexually mature; from 1 to 2 years; in females, nipples are small and surrounded by fur; males have underdeveloped testes regardless of the season; dentition likely to show signs of staining on lateral surfaces (diet dependent), cusps of premolar teeth are becoming slightly oblong, but there is no wear or staining on canine teeth198
 maturea full-sized sexually mature animal (potentially breeding); from 2 years to at least 16 years old; mature males have well developed testes (particularly in the mating season); in females that have bred, nipples are enlarged, irrespective of whether they have lactated recently; also, lactating and post-lactating females have less fur around the nipple; teeth are mostly heavily stained from all sides, often showing signs of discoloration and decay, but in various stages of wear344
season
 spring 2004November 2004, Elsey National Park170
 autumn 2005April 2005, Flora Nature Park103
 winter 2005July 2005, Flora Nature Park (n=69) and Northern Territory Rural College (n=116)185
 spring 2005November 2005, Elsey National Park (n=93) and Katherine River (n=87)180
 autumn 2006March 2006, Katherine Gorge National Park (n=18) and Litchfield National Park (n=8)26
weightbody weight (g)664
forearmlength from the styloid process of the third metacarpal to the olecranon process of the ulna (mm) when the wing is folded; forearm length does not increase once the animal reaches maturity (approx. 2 years)664
weight/forearm ratiobody weight (g) divided by forearm length (mm) gives an indication of body condition by taking into account body size664
lactatingenlarged nipples expressing milk22
pupdependent pup attached to its mother8
pregnantpregnancy detected via palpation34