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

32. Trypanosoma spp.
32.1. HAZARD IDENTIFICATION
32.1.1. Aetiological agents
Trypanosoma evansi is the aetiological agent of surra in animals. Humans are not
susceptible to infection.
Trypanosoma cruzi infects humans and animals and is the aetiological agent of Chagas
disease in humans.
Trypanosoma vivax infects animals but not humans and is the aetiological agent of the
disease nagana in animals.
Other pathogenic trypanosomes such as Trypanosoma congolense, Trypanosoma brucei
and Trypanosoma simiae are typically African parasites and do not occur in any of the
countries relevant to this risk analysis.
32.1.2. OIE list
Surra is listed as a disease of multiple species and trypanosomosis (tsetse-transmitted) is
listed as a disease of cattle. However, there are no Code chapters for either.
Of the tsetse fly transmitted trypanosomes, only Trypanosoma vivax is relevant to this risk
analysis as it is the only species that is transmitted mechanically by biting flies in South
America.
32.1.3. New Zealand status
T. evansi and Trypanosoma spp. are classified as unwanted, notifiable organisms (MAF
2009).
32.1.4. Epidemiology
T. evansi
T. evansi is mechanically transmitted by biting flies. It occurs in Northern Africa, the
Middle East, some areas of Russia, India, China, South-East Asia (as far east as Timor)
and South America (DAFF 2007; Luckins 2008; Uilenberg 1998). It causes surra, most
importantly in camels and horses, but also in cattle, buffaloes, sheep and other domestic
and wild animals. The occurrence of the disease in camelids is controversial. Some authors
list camelids as animals in which surra occurs (Australian Government 2007; Uilenberg
1998). In other authoritative reviews, llamas are not mentioned as animals in which it
occurs (DAFF 2007; Luckins 2008; Uilenberg 1998). Wernery & Kaaden (2002) state that
“Trypanosomosis has not been reported in South American camelids despite the presence
of T. evansi in cattle and horses” Fowler states that “It (surra) has also been reported from
Central and South America, although trypanosomiasis has not been reported from South
American camelids in these areas”. He also states that “ However, trypanosomes have been
isolated from llamas imported into the United States from Chile” giving as reference a
personal communication from a reputable source (Fowler 1992). However, the species of
trypanosome that was isolated is not specified. One expert has stated that llamas may be
infected with T. evansi but specific references to cases are not given (Uilenberg 1998). No
MAF Biosecurity New Zealand Import risk analysis: Llamas and alpacas from specified countries ● 115