UK Alabama rot risk may be linked to certain types of dog breed and habitat
The risk of contracting renal glomerular vasculopathy (CRGV), popularly known as Alabama Rot, may be higher in certain types of dog breed and land habitat, indicate two linked studies published in this week's Vet Record.
The clinical signs of Alabama Rot typically include skin ulcers and anaemia, progressing to kidney damage and renal failure. As yet, the cause is unknown.
The first known cases in the UK were reported in 2012 in the New Forest in southern England, and cases have tended to occur more frequently at certain times of the year, and in certain geographical areas. But it's not clear what other potential risk factors there might be.
In the first study, the researchers assessed whether certain types of breed might be more at risk. They looked at 101 reported cases (out of 103) diagnosed between November 2012 and May 2017, comparing them with more than 446,000 dogs in receipt of veterinary care at practices submitting data on health issues to the VetCompass programme during 2013.
On average, the vet practice dogs were nearly 4.5 years old, and just over half were male. The most common Kennel Club breeds were gun dogs (spaniels and retrievers), terriers, and toy dogs; working dogs and hounds (salukis, whippets, and Hungarian vizslas) were the least common.
Crossbreds made up over a third (just under 38%) of all the dogs, with labrador retrievers, Staffordshire bull terriers, and Jack Russells, the most common specified breeds.
Compared with the vet practice dogs, those diagnosed with Alabama Rot were more likely to be female (58% vs 48%) and neutered (69% vs 45.5%).
Among the Kennel Club breeds, gun dogs and hounds made up nearly two thirds (60%) of the Alabama Rot cases. They were between 9 and 11 times as likely to have been diagnosed as terriers.
Among the specified breeds, Staffordshire bull terriers, Jack Russells and German shepherds were the least likely to have been diagnosed, while English springer spaniels, whippets, and flat-coated retrievers and Hungarian vizlas were the most likely.
"It is possible that these breed associations result from an inherent susceptibility among these breeds as a result of genetic or behavioural patterns, but it is also possible that the predisposition results from geographical confounding whereby these breeds may occur more commonly in areas with a high risk of CRGV occurrence," explain the researchers.
In the second study, the researchers looked only at the 101 dogs that had been diagnosed with Alabama Rot to see if there were any patterns in timing, geography, and terrain.
Most cases (90%) were reported between December and May, with a third diagnosed between January and March. Fewer than one in 10 cases were diagnosed between June and August.
Cases were reported from most of the western and southern regions of England, over the five years, with the lowest risk seemingly in eastern England, in particular, East Anglia.
Habitat emerged as an influential factor, accounting for more than 20 per cent of the difference in the geographical distribution of cases. Dry lowland heathland and woodland areas were the most likely to be associated with a diagnosis, while pasture was the least likely.
Areas with higher maximum temperatures in winter, and higher average rainfall in winter and spring (such as the West and South of England), were also associated with a heightened risk of a diagnosis.
Both these studies are observational, and as such, no definitive conclusions can be reached about causality.
But the researchers say their findings may help raise the index of suspicion among vets, as it is particularly important to treat Alabama Rot promptly, as well as giving dog owners an indication of when to be extra vigilant.
But further research is warranted to find out if the breeds seemingly at higher risk are inherently more vulnerable or whether there are higher proportions of these breeds in areas of greater risk, they conclude.
In a linked editorial, managing editor, Suzanne Jarvis, reiterates this uncertainty, emphasising the need for caution until further research can shed more light on the matter.
"The next step is to see if this suspected geographical connection holds true; what it is not, is to scare owners of these identified breeds," she insists.
Kim B Stevens et al. Spatiotemporal patterns and agroecological risk factors for cutaneous and renal glomerular vasculopathy (Alabama Rot) in dogs in the UK, Veterinary Record (2018). DOI: 10.1136/vr.104892