...here is a recent varient. I've also seen "multi factoral" used.

1: Cell Transplant. 2006;15(3):239-50.

Progressive dopamine neuron loss in Parkinson's disease: the multiple hit
hypothesis.

Carvey PM, Punati A, Newman MB.

Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612,
USA. pcarvey@rush.edu

Animal models have been an essential tool for researchers and clinicians in
their efforts to study and treat Parkinson's disease (PD). Thus, the various
ways 6-hydroxydopamine is employed, the use of MPTP in rodents and nonhuman
primates, the prenatal exposure to bacterial endotoxin, the postnatal exposure
to environmental toxins such as paraquat and rotenone, the assessment of
dopamine (DA) neurons in genetic knockout mouse, and even the behavioral
analysis of fruit flies and worms have added significantly to our knowledge base
of PD--or have they? Are these animal models manifesting a true model of PD?
Have the 7786 published studies (to date) on PD with animal models led to a
clearer understanding of its etiology, treatment, or progression? In this review
we critically assess this question. We begin with a succinct history of the
major contributions, which have led to the current animal models of PD. We then
evaluate the primary issue of the progressive loss of DA neurons, which, except
for a few studies, has not been addressed in animal models of PD, even though
this is the major pathological characteristic of the disease. Lastly, we discuss
the possibility that more than one risk factor for PD may be necessary to
develop an animal model that shows synergy--the progressive loss of DA neurons.
Thus, the multiple hit hypothesis of PD-that is, the effect of more then one
risk factor-may be the start of new era in animal models of PD that is one step
closer to mimicking the pathology of PD in humans.

PMID: 16719059 [PubMed - indexed for MEDLINE]