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

21. Brucella spp.
21.1. HAZARD IDENTIFICATION
21.1.1. Aetiological agent
Brucella abortus, Brucella melitensis, Brucella suis, and Brucella ovis.
21.1.2. OIE list
Bovine (B. abortus), porcine (B. suis) and sheep and goat (B. ovis and B. melitensis)
brucellosis are listed.
21.1.3. New Zealand status
B. abortus was eradicated from New Zealand by 1989 (Hellstrom 1991; Mackereth 2003).
B. melitensis and B. suis are not present. B. abortus, B. melitensis and B. suis are unwanted,
notifiable organisms (MAF 2009). B. ovis is endemic.
21.1.4. Epidemiology
Information on the global occurrence of Brucella species and brucellosis is available from
the World Animal Health Information Database (OIE 2009). Bovine brucellosis formerly
had a world-wide distribution but has now been eradicated from many developed
countries. Canada and Australia are free from the disease. It still occurs, but at a low
prevalence, in the USA and in some parts of the EU, Central and South America and Asia.
B. melitensis affects goats primarily but also sheep and occurs in some countries in Europe
and South and Central America but not in Australia, the USA or Canada. B. suis occurs in
some European, Asian, South and Central American countries and at a low prevalence in
the USA. The last occurrence of B. suis in Australia was reported in 2004. The UK is free
from all Brucella spp.
Brucellosis is a rare disease of camelids. Fowler (1998) reviewed a report in which an
outbreak caused by B. melitensis is described. He also reviewed a paper describing the
death of three llamas after exposure to camels recently imported from Russia. These
animals had high antibody titres to Brucella. However, this report must be viewed with
some scepticism since brucellosis never causes acute fatal infections in adults of other
animal species. Nevertheless, Nielson (2008) reports brucellosis in camelids related to
contact with large and small ruminants infected with B. abortus or B. melitensis. Llamas
have been experimentally infected with B. abortus. The only pregnant llama in the exposed
group aborted and the organism could be isolated from the placenta, foetus and various
organs in the dam (Gidlewski et al 2000). Antibody was detected in llamas experimentally
exposed to B. abortus S19 (vaccine strain) and strain 2308 (Gilsdorf et al 2001). Exposed
camelids developed antibody that was detectable by a range of conventional serological
tests (Gilsdorf et al 2001; Rojas et al 2004) but difficulties were experienced when using
the complement fixation test due to anticomplementary activity of the sera (Rojas et al
2004).
No evidence was found of natural infection of camelids with B. suis, but since this
organism is closely related to other Brucella spp. (B. abortus and B. melitensis) it is likely
that it could be infectious for camelids. It is unlikely that B. ovis would be infectious for
MAF Biosecurity New Zealand Import risk analysis: Llamas and alpacas from specified countries ● 73