http://www.independent.com.mt/news.asp?newsitemid=77067

[Daphne – I know. She thinks I’m a rapist.]

Our problem is that we are endemically under funded as far as human resource and running costs are concerned – and as you know we have to work on a project by project basis – so our jobs are usually short term (3 years or so) – but keep a look out for opportunities if you are really interested (send me an email) :)

Oh yes, you’re right. Tal-Fenek and Ibizan hounds are virtually one and the same, with a few differences. Hadn’t noticed that. Lovely dogs!

Here again, in the way of confirmation, is the summary of a scientific paper studying Ibizan hounds and showing that their cellular response on encountering the parasite is more significant than that in other breeds:

“Veterinarians working in the Balearic Islands (Mallorca), an endemic region of canine leishmaniosis, have reported very few cases of leishmaniosis in Ibizian hounds while concurrently observing that dogs of other breeds had a high incidence of clinical canine leishmaniosis. To further investigate this observation, two populations of dogs from the Balearic Islands were examined for the presence of Leishmania-specific cellular immunity using a delayed type hypersensitivity test (DTH) to leishmanin and for the presence of Leishmania-specific humoral immunity using an ELISA. Fifty-six asymptomatic dogs, 31 Ibizian hounds and 25 dogs belonging to other breeds were examined. Seventy-seven percent of the dogs demonstrated a specific immune response against Leishmania, either humoral or cellular. This finding suggests that the infection rate (77%) was higher than previously considered. For Ibizian hounds 81% were DTH positive while only 48% of the other dogs were DTH positive. A statistical association between Ibizian hounds and positive DTH response was found. A specific humoral response was found in 48% of Ibizian hounds and in 56% of the other dogs. No statistical association relative to the Leishmania-specific IgG1 and IgG2 levels were found between the two groups. The Ibizian hound has been reported to be more resistant to Leishmania infection and we found that the Ibizian hound mounts a significant cellular response to infection. Thus, the Ibizian hound may be an interesting canine model for the investigation of protective anti-Leishmania immune response.”

http://www.ncbi.nlm.nih.gov/pubmed/10828510

[Daphne – I believe the veterinarian Victor Vassallo was researching the matter of leishmaniasis in respect of tal-fenek some 10 years ago or so.]

At the moment I’m employed as what can be loosely termed a paint chemist … have you got a new job lined up for me :D ?

Most notably, it was found that Ibizian hounds are extremely resistant to Leishmaniasis, whereas North American foxhounds were found to be more prone than other dogs to contract it. One would therefore presume that the Maltese Tal-Fenek hound enjoys the same resistance as its Ibizian counterpart.

http://www.susanamendez.com/LeishmaniaFacts/Canine.html

To make things even more complicated, even within the same breed, individual dogs may be more or less susceptible to infection according to their genotype. The following article is very technical, and I am simplifying a very complex subject, but Dr Scerri may be kind enough to explain it in further detail.

http://jhered.oxfordjournals.org/cgi/content/full/96/7/755

Of course, once this is the case, it would not be too far-fetched to imagine that humans, too, might have different susceptibilities to infection by the parasite, according to their different immune responses to the latter, and ultimately according to their different genotypes.

Hope that this is helpful.

[Daphne – That’s interesting, because the Ibizan hound is virtually the same breed as the tal-fenek.

The main difference is in its markings – Ibizan hounds have a greater variety of white markings, and they are slightly larger. Basically, the Maltese dogs are believed to be descended from the same group of Ibizan hounds brought to this island and left to breed in isolation. They can live independently of humans and are still quite feral even when living in homes – ours would not allow us to stroke her and spent her days wandering. They’re good hunters, feeding off rodents. They may actually have survived even during the period when Malta was depopulated around 1200 years ago because they are not really domestic. I wish more would be done to champion this breed, and even to investigate it genetically before they all die out. There is no longer even one in the farm area where I live.]

Alex Felice still heads the lab so in a way I should have used the word “our” :)

@ Daphne – I thought you were referring to that orthodontist – he is in fact the one that is actively researching the genetics of ectopic maxillary canines! The world is really a small world!

Yes, I sympathise. We’ve had dogs in the past, lived in an urban area and still, all our dogs died from Leishmaniasis, after being given whole courses of antimonials and suffering the side-effects, including going blind. :( :(

Yes, the disease is endemic in Malta, and when it attacks humans it usually attacks children. The incidence in Gozo is higher than that in Malta. One paediatric study quotes 81 cases between 1980 and 1998 (4.5 cases per year), and these were cases of Visceral Leishmaniasis (VL). One presumes that during the same period, there were also cases of Cutaneous Leismaniasis (CL), which is becoming more frequent in Malta.

Of course a much larger number of dogs are affected per year. Why? I imagine that it is because the immune response triggered in dogs may not be as strong as that triggered in humans, making them more susceptible to the infection…. same as the immune response triggered in children seems to be weaker than that in adults, which makes them more prone to contracting Leishmaniasis. It is all, I guess, a matter
of the different way in which a dog’s immune system reacts to being “attacked” by the parasite.

With regards to other factors (apart from the immune response), my vets had other theories along the years: dogs spend their days lying on ground/ soil where the sand-fly may be breeding, whilst human being do not. Children are more prone to sit/ play on the floor than adults do, thus making them more prone.

I’m sure you’ve been told that keeping dogs inside after dusk helps (probably very hard to do), and that the frequent spraying with insecticide of the outside areas they prefer to sleep and rest in may reduce the incidence of infection.

Re the Maltese being more resistant to Leishmaniasis than others: I simply do not know that.

You might be interested to know that potential vaccines are being tested, with some promising results:

http://www.sciencedaily.com/releases/2005/08/050814165616.htm

[Daphne – Thanks for the link. Well, that’s good news. Yes, it is impossible to keep them in after dusk, particularly in the summer when the problem is greatest. They also need to be let out before dawn, which is another problematic time. I remain curious, though, as to whether indigenous tal-fenek dogs have a higher resistance (not those bred overseas, but the semi-wild ones in farm areas). One would imagine that they might, because the disease is such a killer that there is no way they would have survived in such large numbers in rural areas for so many centuries.]

Your orthodontist seems to have read some of the papers produced by our team as well as his history well. Congrats to him or her.

[Daphne – The orthodontist is Simon Camilleri. I’m sure he’d want to know about this research.]

I am Reuben Scicluna. I had prepared my dissertation in the lab then headed by Prof. Alex Felice. I don’t know whether or not he still heads it today, probably not though, since you refer to it as “my lab” …

Now I know who you are ;) very well read and always a pleasure to deal with.

Nice to “meet” you again :)

Reuben

As you know there are 100’s of G6PD variants, some very common others rare. And if any of these have been discovered within the Maltese population it does not mean that they are not present in other populations. Also, though you are right that G6PD carriers (females) have some protection against Malaria (similarly to Thalassaemia and Sickle cell disease), spontaneous, di novo mutations do occur and can happen within the any time frame – so one can never say never.

On the other hand as I said, taking a single mutation, without even looking at the background framework of polymorphisms, on cannot define neither ancestry nor its origin. I can mention numerous exqamples e.g. Thalassaemia – the most common mutation (75%) is only found at a rate of 20-25% in the Med and in Malta it is found within two frameworks whilst another mutation – IVS2-1A – is very rare in the Med but common in Armenia and the most common in Iran – but again this is no proof that “our” IVS2-1A originated from this area.

In reality, the Maltese population has very strange genetics due to what is known as founder affects – basically most of our mutations were “imported” in the country in the last 500 years or so -mostly through immigrant workers from Sicily and Southern Italy as well as from the various sailors that found refuge in our country during the harsh Mediterranean winters. I shall leave the rest of the story to your imagination – but you can imagine where the the offspring arose from! :)

As for pharmacogenomics – your are mixing race with ethnicity – two different things. Polymorphisms i.e. DNA variations, do segregate within ethnic groups – basically due to the geographical isolation of most groups (at least up to around 100 years ago) and thus it is easier to search for these difference in these ethnic groups – as an aside, that is why the Maltese population makes a very interesting study group for these companies and thus a possible commercially viable undertaking. For this reason I have been championing the study of genetics amongst the Maltese and lobbying the powers to be (unfortunately not always with great success). We can have a similar commercial activity like deCOde of Iceland – the infrastructure is there and shall be augmented substantially (basically to a level of a unique state of the art lab in the Mediterranean) within the next couple of years.

@ Kenneth Cassar – I cannot agree more with you.

[Daphne – I sometimes get the sense, when speaking to a total stranger, that he/she could be a member of my family because of some strikingly familiar physical characteristic, then I realise that in Malta this is very possible because, with people who don’t even know they are very distantly related marrying each other, there’s a strong chance of recessive genes coming to the fore. I’ve often remarked how much X reminds me of Y only to be told they are not even remotely related – as far as they know. Just to give one prosaic example of what you are talking about, in real physical terms – my right front-tooth traverses the left, a hereditary trait that pops up very, very randomly in my family. Because I would have rather died a slow death than wear a brace at 14, it’s something I have to live with. When I took one of my sons, who had the same problem, to the orthodontist, he said that this is one of the most common problems he has to deal with in Malta (he also works overseas). “It’s almost certainly all down to one sailor who fed this gene into the population 500 years ago,” he laughed. “It’s clearly the same gene, and the right tooth always traverses the left, not the other way round.” After he told me this, I began to notice just how many people of my generation and older – from the days when braces where hideous contraptions or just didn’t exist at all – actually have front teeth like these, including my own mother-in-law, which is probably why the same fluke popped up immediately in one of my kids rather than randomly missing a couple of generations as it did in the rest of my family. And yes, in almost all cases that I’ve seen, the right tooth crosses the left.]