Import risk analysis: Llamas (Lama glama) and alpacas (Vicugna ...

(Thornley et al 2002). Leptospirosis occurs world-wide and in all countries covered by this
risk analysis. The endemic serotypes in each country differ.
Leptospires spread in water and mud contaminated with infected urine. Infection can occur
by mouth or through the skin, particularly through abrasions and wounds. Diseased
animals shed more organisms and are more important sources of infection than chronic
carriers (Horsch 1989).
In accidental hosts, the incubation period may be from 2-16 days and is followed by a
period of bacteraemia. A variety of signs may be shown by diseased animals including
abortion, haemolytic anaemia, icterus and nephritis. The disease can be diagnosed by the
isolation of the organism, but because this is a difficult and lengthy process (taking up to 6
months) infection is more usually diagnosed by serological methods, with a rising titre
signifying recent infection and a stable, often low level titre indicating resolution or a
chronic infection. Serological methods are available but are difficult to interpret due to
cross reactions between various serovars and problems related to selection of suitable cutoff
points for interpretation and reproducibility of results. The microscopic agglutination
test is still the most commonly used herd test but a number of variations of ELISAs are
also available. ELISAs generally lack serovar specificity (Bolin 2008).
Leptospirosis is seldom the cause of economically serious disease in animals and is mainly
of concern because it is zoonotic and occasionally causes serious disease in humans
(Thornley et al 2002).
Leptospira spp. are sensitive to several antibiotics (Oie et al 1983; Gerritsen et al 1993;
Gerritsen et al 1994; Alt et al 2001; Murray & Hospenthal 2004). In particular
streptomycin and penicillin have been extensively used for prophylaxis and treatment of
live cattle, semen and embryos in international trade.
Vaccination of animals against the main serovars occurring in New Zealand is widely
practised, with the aim of developing an immune population thereby reducing the risk to
humans that are in contact with the cattle.
There is little information about leptospirosis or Leptospira infections in camelids.
Infections have been described in alpacas and a 3 month old guanaco (Wernery & Kaaden
2002). Leptospirosis has been implicated as a cause of abortion (Chenoweth 2006). In
North America reported infectious causes of abortion in camelids includes leptospirosis
(Tibary et al 2006). In a serological survey in Argentina, the prevalence was 36 % (Marin
et al 2008). In another study in Argentina the prevalence varied from 47 to 96 % in llamas,
0 to 13 % in guanacos and 9 to 63 % in vicunas (Liorente et al 2002; Tibary et al 2006).
Antibody was detected against L. ballum, L. bataviae, L. icterohaemorrhagiae, L. pomona,
L. pyogenes (Marin et al 2008), L. copenhageni and L. castellonis (Liorente et al 2002). It
can be concluded that leptospirosis is a rare disease of camelids but that subclinical
infections are relatively common. Therefore, camelids can be accidentally infected and
could be carriers of particular Leptospira serovars, but it is not known which serovars, if
any, they act as maintenance hosts for.
In North America, llamas in some locations are routinely vaccinated against leptospirosis
with commercially produced vaccines intended for cattle (off-label use). However, the
serological response is inconsistent in vaccinated camelids. No serological response to any
or, only some of the poly-valent serovars contained in the vaccine occurs. Generally the
90 ● Import risk analysis: Llamas and alpacas from specified countries MAF Biosecurity New Zealand