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

28. Pasteurella multocida types 6B and 6E
28.1. HAZARD IDENTIFICATION
28.1.1. Aetiological agent
Pasteurella multocida strains are classified into five capsular antigen types (A, B, D, E and
F) and 16 somatic antigen types (De Alwis 1999). Capsular typing is done by various
methods described by Carter, Heddleston, Namioka and Murata. If the Namioka-Carter
classification method is used the types that cause haemorrhagic septicaemia are 6.B and
6.E. In the Heddleston-Carter system the synonyms for these strains are B:2 and E:2
(Srivastava et al 2008). Other types are associated with pneumonic pasteurellosis.
28.1.2. OIE list
Haemorrhagic septicaemia is listed as a disease of bovidae (cattle and buffaloes).
28.1.3. New Zealand status
Pasteurella mutocida types B:2 and E:2 (6.B and 6.E) are listed as unwanted, notifiable
organisms.
28.1.4. Epidemiology
Haemorrhagic septicaemia is predominantly a disease of cattle and buffaloes and they are
the reservoir hosts. It occurs in, but is not restricted to, tropical and sub-tropical countries
of Asia and Africa. It does not occur in Australia or Canada, and has been suspected but
not confirmed in the USA. It occurs in Brazil and has previously occurred in Argentina and
Panama (OIE 2009c). In the 27 countries that make up the EU it has occurred only in Italy
and Portugal during the last 3 years (OIE 2009c). In Africa, it is caused by Pasteurella
multocida types B and E and in Asia by type B (Carter 1998; Bastianello & Henton 2004).
The incubation period in naturally acquired infections is from 1-3 days (De Alwis et al
1990; De Alwis 1992; Carter 1998; Bastianello & Henton 2004). The course usually varies
from peracute to subacute but inapparent infections also occur. Peracute infections are
characterised by sudden death, while acute cases show fever, profuse salivation, nasal
discharge, and rapid respiration. Firm subcutaneous swellings in the submandibular region
are seen in subacute cases. Untreated cases usually end fatally (Bastianello & Henton
2004). Animals that survive infection may be active carriers for 4-6 weeks and then
become latent carriers. In herds recently exposed to the infection, up to 23 % of animals
may be latent carriers for at least 229 days (De Alwis et al 1990; Bastianello & Henton
2004) with the organism being harboured in the nasopharynx, retropharyngeal lymph
nodes, and tonsils, from which it is periodically shed when the animal is stressed (De
Alwis et al 1990; Bastianello & Henton 2004). The organism is excreted in respiratory
aerosols, saliva, urine, faeces and milk. Transmission is by the respiratory route or on
fomites.
Resistance to antibiotics has not been described and treatment with sulphonamides and
antibiotics is effective in controlling outbreaks of the disease (Bastianello & Henton 2004).
However, treatment is not effective in eliminating the carrier state (De Alwis et al 1990).
104 ● Import risk analysis: Llamas and alpacas from specified countries MAF Biosecurity New Zealand