Leptospirosis: WHY Is It Killing So Many Cubs?

 

We have, in Bristol, another possible case of leptospirosis Weil's Disease). I write "possible" since until it has undergone a post mortem and various tests nothing is conclusive.  

If I go by what some rescues say then every year fox cubs are dying with symptoms such as convulsions, collapse, their whole system shutting down and jaundice.

Every year.

I ask what the post mortems concluded and without fail I am told that they do not have foxes undergo PMs -if disease or poisoning is suspected then the post mortems are free of charge if you contact the nearest Animal Plant Health Agency office and explain. You will, however, have to transport the body yourself as there is no collection service.

Some shrug off the annual deaths as "canine hepatitis" or "distemper" despite the fact that we have had neither of these in UK foxes to date.  As one told me: "We will decide to submit any such dead animal when we think it necessary" and then told me it was all canine hepatitis. Just as rescues told me that "adenovirus is rampant in UK foxes" yet, many post mortems later we have had no adenovirus in Bristol foxes. It's just an easy dismissal of deaths to cut back on doing something about them.

But why cubs every year -and for how long has this been going one?  For the latter the response is simply "we do not know" because no one has been recording fox deaths or the ages of those foxes. If this has been going on at the same time as hunting and idiots out shooting foxes for 'fun' every night then it explains why the UK fox population is now needing to be considered for Red Listing rather like the hedgehog was/is.

The high number of vixen cubs is worrying since they are the ones that would rear the next generation. Shooters have no concern whether it is a dog or vixen they shoot or a cub; they just kill for 'fun'. As hunts found in the past, though even when writing about it and explaining the situation it just never sank into their own brains; you kill vixens -where do future foxes come from? You kill cubs -no adult foxes later on, Killing a vixen to prove that she was pregnant because someone challenged a persons statement that she was pregnant....

This is how people killed off the UK/Irelands original fox types by the 1830s and importing foxes had begun long before and after that. Since the early 1900s (say post 1914) foxes could not be imported and released for hunting.  Mange (introduced by hunts through importing under poor conditions) seen in one fox meant every fox in the area was killed "in case" (just import more).  We have seen near extinction of new UK foxes a number of times -1925 and the 1950s seeing them teetering on the brink.

The foxes we have left now are it and many thousands die on roads every year and hundreds shot for 'fun' while lung and heart worm and verminous pneumonia claim many others. You cannot keep killing a species (just one of many that people are still wiping out in the UK) and expect it to survive. Badgers are already teetering on that cliff of extinction.

This is why we are trying to find out what is killing foxes and leptospirosis has been the big surprise.  Although known in foxes outside the UK those foxes tend to show some immunity to lepto as well as babesia why are UK foxes dying from lepto?

There are a number of factors and one may well be that the healthier foxes that would breed new, stronger generations with immunity are being killed off. The second may well be environmental.  Rats are a foxes main prey in towns and cities and they kill hundreds each every year and are possibly the best pest control you can get. Rats carry a lot of diseases but, healthy foxes should build up an immunity to those.

In the past we had colder winters (very few of them in the last 20+ years) and as no one was checking dead foxes we cannot know if more died during/following cold winters as do after mild winters.  The cold used to freeze the ground and to an extent kill off bacteria, etc., and heavy rains would dilute any remaining. Cold and wet winters seem to be good for keeping down infection outbreaks in theory.  The reality is that we get the opposite.

Warmer winters and no freezing of the ground creates, I believe, pockets of bacteria that run rife. 

We know that there is no shortage of food for foxes -mice, rats, insects, fruit, etc. as well as littered food. There are also feeders and this has other effects (for another post) but it means that in some ways a fox diet is changing. They should not be fed a large amount every day and the "healthy looking" foxes I see on social media get lots of "Likes" but they are obese. A fox is supposed to look "rangey" as they are hunters and need to dart through and around obstacles to catch prey.

Weather is, however, another contributor since we are seeing butterflies, bees, ladybirds and many other insects that should be dormant out and amount in November, January and so on. I keep a watch on all local wildlife and I know for a fact that hedgehogs are also affected by milder winters. I make sure that they get enough supplemental food that they have a good weight for hibernation. In the last 10 years I have seen hogs out and about in November, December, January and February when it was warmer and wet. Most people tend to think winter months means they are not about but they are.

So, yes, the changes in climate are having an effect on wildlife as well as other aspects of life and I believe that the reason so many cubs are dying from lepto is because of this change. The freezing temperatures can kill off the bacteria within minutes as they are fragile (they also die in dry heat, etc.)  Because of this, leptospirosis cases are supposedly less common in the winter, with most cases occurring during the summer and autumn. 

Cubs are exposed to the infection at an early age before they have reached adulthood and

 build up an immunity. Sadly, the financial backing is not there for such research as It is "just foxes."