When I said dead bodies I meant any outbreaks of disease in the camp, I think that was a problem on that very campaign you mentioned.
Basically what I'm getting at is why not allow the Huns to bleed out more while in Gaul and burn themselves out before you make battle, but that question has been answered.
As slydessertfox said, Aetius positions would have been extremly perillous if he let Roman Gaul, or what remained of it, being plundered by Attilla.
Basically everything happening in Gaul since the early 440's, is based on Aetius alliance with Huns, and letting the region to them (even temporarily) would be both disobeying Ravenna's orders and appear as responsible of the whole situation.
In a Roman court where anti-barbarism was on the rise, with an Aetius possibly seen as an half-Barbarian (far less than Stilicho, arguably), and considered as responsible to the loss of Gaul...That would probably involve Aetius' head and a plate, eventually.
Stalling would have been tactically unwise as well : we know that Alans tried to switch sides, only to be stopped by Theodoric and Aetius. An unopposed Hunnic force would have probably managed to at least buy the neutrality of most federates, Aetius potential allies' numbers being reduced as much.
That said, I don't remember mentions of an epidemic outbreak among Hunnic armies, but that wouldn't be improbable. Can I ask where did you saw that?
EDIT : Wouldn't you confuse with Atilla's campaign in Italy?
what is the best strategy he could have adopted with regards to the Huns from the time he (Aetius) takes power and on?
Well, the easy answer (too easy?) is : what he did.
The main problem of the first half of Vth century was the Barbarian presence in Romania, that grew more and more important and more and more powerful.
Aetius basically played Huns against peoples such as Franks, Burgundians, Goths.
It's to be noted that his links with Huns (and the fact they were the only Barbarians without regional hegemony within Romania, so less of a political threat) didn't played only against Barbarians, but against Romans themselves : under Iohannes, he used Huns auxiliaries against Valentian's supporters; under Valentian, he used them against Bonifacius, etc.
Now, I think it's possible, if you manage to divide more important Huns, to have a slightly different policy : being more aware of the danger Huns could represent, having a less important dependency to them.
Basically, maintaining Hunnic kingship divided as long as possible, having a PoD increasing inner fights, ending with some Huns as foederati in Gaul or Norica, and a lesser danger using them and divided Huns as military force.
But, frankly, I'd think Aetius' policy was mostly sound when it come to these matters.
Do you have any other insights about the late Roman Empire?
Erm...That's a really dense subject, and I don't want to derail the thread more than it could support. Maybe send me a PM about what you search (or that I could advise you some interesting sources about the period) or create a thread if it's more about a precise topic? (Would it be because I'm far from being infallible, and I wouldn't want to mislead you : more members on it would be a better thing IMO)
Basically,the Huns would have to ravage much of Rome's lands in northern Gaul before they can ravage Visigothic Aquitaine or Burgundy.
That's not that obvious.
Atilla was wary of the Gothic power in southern Gaul, and it's why he tried to make an agreement in 451 with Theodoric. Would have he attempted that, Theodoric would have an easy time leading a comparable confederation than IOTL (except it wouldn't be a "Roman" led one, but a Gothic one) with Burgundians, Armoricans, possibly Franks and Gallo-Roman forces (such as Avitus, but not only).
Not that it wouldn't be possible, but in this case, I wouldn't see an earlier Gothic hegemony in Gaul
à la Euric as unthinkable.
That said, Atilla did, IOTL, plundered most of Northern Gaul between Rhine and Seine. It's just that Aetius made him abandon the results of his plundering.