Syria Refugees Are Not Carrying a Flesh-eating Disease

ISIS has been accused of causing a 'flesh-eating bacteria' to spread in Syria and therefore in Europe. Not exactly.

AP

The latest panic ascribed to ISIS is that it’s causing the “flesh-eating bacteria” leishmania to spread in Syria, by leaving bodies to rot in the streets. Syrian refugees are being charged with bringing the disease to Europe where they could potentially infect others, according to media reports that began with a Kurdish Red Crescent official speaking with the Kurdish media network Rudaw. Leishmania is not a bacteria. It’s a protozoan parasite. It does not “eat flesh” like the real streptococcal “flesh eating disease” but does cause lesions. The sores may be unsightly but are not fatal (with very rare exceptions). The lesions can be very hard to get rid of, but in contrast to real necrotizing “flesh-eating bacteria,” the disease is usually unpleasant but not dangerous.

It is possible for infection rates among host communities of Syrian refugees to increase, if the other conditions are in place – namely the appropriate animal host and vector, which is the female sand fly. But leishmaniasis existed in Europe well before the refugees, even sporting its own set of asymptomatic carriers.

Chaos in Syria

The incidence of leishmaniasis is apparently indeed rising in Syria, and dramatically at that. The true dimensions of the problem are hard to know given the collapse of civil authorities there able to provide reliable data.

The last available figure is for 2011, which cited 58,000 cases of the common form of leishmaniasis in Syria, says an Israeli expert on the disease, Dr. Eran Cohen-Barak of the Clalit Health Services hospital Haemek in Israel. He adds that the figure probably represents under-reporting.

If incidence of the disease really is increasing dramatically, ISIS can be fairly blamed, not because it’s leaving corpses about specifically – but because the destruction and chaos the organization is causing lead in turn to the proliferation of rats, which are a stage in the parasite’s life cycle. Even when ISIS “creates,” for instance by building new bases where none had existed before, that again causes rats to multiply because now they have a new source of sustenance.

Could refugees from Syria infect Europeans with leishmaniasis? Absolutely not directly, says Cohen-Barak, clarifying: “Human-to-human infection of leishmaniasis is practically unknown.”

Like malaria, the leishmania parasite is spread by a blood-sucking insect, in its case the phlebotomine sand fly. Its proliferation also requires a host animal (see life cycle graphic below). So: If a refugee has the disease, and the host animal is there, and the sand fly is there, then yes, refugees could pose a source of infection.

Leishmania gets around

However, Europe didn’t need refugees from the Middle East to bring the disease. Leishmania already exists in much of the world. The phlebotomine sand fly that spreads it thrives anywhere between latitude 50°N and 40°S (see map below). That encompasses Africa, most of North and South America including the entire United States and a bit of southern Canada, Australia, most of France and some of Germany, all of China and much of Mongolia and Kazakhstan but little of Russia, where it’s too cold for the insect. (New Zealand has been spared the fly’s attentions.) Global warming is likely to cause its range to increase.

A map of the world marking the range of the sand fly, from 50 degrees North to 40 degrees South.
Google Maps

So, leishmaniasis is already common in the Middle East, parts of Africa and southern Europe. Also, forms of the disease exist in most of the United States, Europe, Asia, Africa and of course the Levant, where it has existed and been documented for thousands of years. Apparently leishmaniasis is the disease referred to in 2,700-year old tablets associated with the Assyrian king Ashurbanipal, which are believed to rely on texts some 2,000 years older than that.There are 20-plus varieties of leishmania itself. All are spread by bites of the female sand fly – though each leishmania species also requires its own host animal, such as rats, rock hyraxes and dogs.

The various leishmania species cause three basic forms of disease: cutaneous, mucocutaneous and visceral. The cutaneous form is the most common, especially in the Middle East: Almost all the cases in Syria (and in Israel, where the disease is known as “Rose of Jericho”) belong to this category, which causes ugly skin lesions and can disrupt functioning, for instance when the lesions are on the palm of the hands, says Cohen-Barak. But it isn’t deadly. Neither is the mucocutaneous form, which also affects the nasal and mouth membranes.

The visceral form, affecting internal organs too, can be fatal, explains Cohen-Barak. This form, for which dogs can serve as the mammalian host, is extremely rare in the Middle East but is more common in South America. Only 19 cases of visceral leishmaniasis were reported in 2010 in Syria and only isolated cases have been noted in Israel, says Cohen-Barak.

Even the mildest form, cutaneous leishmaniasis, may take years to heal, if it heals at all. The treatments for the different subspecies of leishmania differ, as does their efficacy.

So, yes, the refugees are bringing leishmaniasis and, conditional on the other mammalian host and sand flies being in position, the refugees could infect their hosts. Who can get cured. For all the ugliness and painfulness of the lesions, this is not a flesh-eating bacteria, and leishmaniasis existed in Europe before the first Syrian refugee arrived.

The symptoms of cutaneous leishmania, by the way, span the range from none (“silent” infection) to one or more sores on the skin, which may start as bumps and progress to ulcers with raised edges and “craters” in the middle. They may not be painful at all, or extremely so. The mucocutaneous form involves sores in the nose and mouth too. The visceral form, which is the most dangerous, may also take silent form, or may progress to fever, weight loss, swelling of spleen and liver and low red and white blood cell counts. Nobody actually knows how many cases of leishmania there are in the world, let alone in Europe or Syria, partly because of the incidence of silent carriers.

There are no existing vaccines against the parasite and the best advice doctors have for prevention: If you live in an area featuring sand flies, sleep with a mosquito net around the bed.