Rusa Deer Cervus Timorensis Russa Research Articles

Rapid Leptospira identification by direct sequencing of the diagnostic PCR products in New Caledonia

BackgroundMost of the current knowledge of leptospirosis epidemiology originates from serological results obtained with the reference Microscopic Agglutination Test (MAT). However, inconsistencies and weaknesses of this diagnostic technique are evident. A growing use of PCR has improved the early diagnosis of leptospirosis but a drawback is that it cannot provide information on the infecting Leptospira strain which provides important epidemiologic data. Our work is aimed at evaluating if the sequence polymorphism of diagnostic PCR products could be used to identify the infecting Leptospira strains in the New Caledonian environment.ResultsBoth the lfb1 and secY diagnostic PCR products displayed a sequence polymorphism that could prove useful in presumptively identifying the infecting leptospire. Using both this polymorphism and MLST results with New Caledonian isolates and clinical samples, we confirmed the epidemiological relevance of the sequence-based identification of Leptospira strains. Additionally, we identified one cluster of L. interrogans that contained no reference strain and one cluster of L. borgpetersenii found only in the introduced Rusa deer Cervus timorensis russa that is its probable reservoir.ConclusionsThe sequence polymorphism of diagnostic PCR products proved useful in presumptively identifying the infecting Leptospira strains. This could contribute to a better understanding of leptospirosis epidemiology by providing epidemiological information that cannot be directly attained from the use of PCR as an early diagnostic test for leptospirosis.

A review of the diet of Rusa Deer Cervus timorensis russa in New Caledonia: Are the endemic plants defenceless against this introduced, eruptive ruminant?

Rusa Deer Cervus timorensis russa was introduced to New Caledonia in 1870 from Java, and has colonized the main island of Grande Terre, where it is found in virtually all the terrestrial biotopes. Despite its abundance and its socio-economic importance for New Caledonians, little is known about the diets of the wild deer populations living in contact with native vegetation which has a high degree of endemism and which, until recently, evolved without ruminant herbivores. We collected information on the diet of Rusa Deer in New Caledonia from published and unpublished reports, a questionnaire addressed to experts and preliminary data from browse-surveys. All sources of information suggested that wild Rusa Deer in New Caledonia is a mixed-feeder, and the list of plants consumed included 25 grasses, 15 forbs, 26 trees/shrubs and 12 vines and ferns. Nearly half (49%) of the plants identified as principal and preferred foods were introduced species. Physical defences (spines and thorns) did not seem to deter deer. It is remarkable that many of the avoided plants were native species (56% of the avoided species). Further research is required to confirm these results, but they are relevant to the evolution of plant/herbivore interactions and to the management of deer populations for conservation perspectives in island ecosystems.

Role of Rusa deer Cervus timorensis russa in the cycle of the cattle tick Boophilus microplus in New Caledonia.

Two field experiments were conducted to evaluate the efficiency of Rusa deer in the development of the cattle tick Boaphilus microplus in comparison with that of steers in the same pastures and under the same conditions of infestation. No difference was noted between a mixed steer/deer herd and a pure steer or pure deer herd in the infestation pattern of each host, suggesting that attachment to the alternative host is mechanical and not affected by the simultaneous presence of the primary host on the pasture. Deer are capable of producing engorged viable females, with weight and reproductive performances similar to or even better than females fed on steers. For moderate levels (1 million larvae per hectare) and high levels (32 million larvae per hectare) of pasture infestation, tick burdens on steers were not very different (e.g. average 1,911 and 2,681 ticks per m2 skin, respectively, on day 24). This may be because of saturation of steer skin sites at the moderate larval dose. Deer harboured 2.7-33 times fewer ticks than steers and produce no engorged females at the moderate larval level and 32 times fewer engorged females than steers at the high larval level. Infestation of deer was dose-dependent with averages of 12 and 399 ticks per m2 skin on day 25 at the moderate and high larval levels, respectively. At a high infestation level of the environment, Rusa deer may contribute, but to a limited extent, to infestation of pastures and, consequently, of cattle. However, their role in sustaining a viable tick population requires further investigation.