"Infectious disease with compulsory declaration induced by a bacteria parasiting numerous animals, especially rodents (rats) and present in aqueous habitats , preferably warm."
This is the zoonosis (animals and human diseases) probably the most widespread in the world.
It is found in rat, dog, livestock and it is transmissible to man..
It is a bacterial disease owed to Spirochetes bacterias (spring shaped bacterias) of the genus Leptospira.
A single specie is pathogenic for man: Leptospira interrogans, for which it exists numerous serotypes (= race, for bacterias).
There is between 100 and 200 known different serotypes of leptospires in the world, often associated with an animal specie.
In French Polynesia ther were counted at least about twenty.
The Leptospira interrogans ictero-haemorragiae serotype is the most common, halas, it is the origin of the majority of the serious forms.It is associated with rats.
Then, we found, for Tahiti Island, in the decreasing order of encountered registered cases, mainly the forms australis (austral=South), canicola (canis=dog, cola=goes with) and cynopteris (cyno=dog, pteris=wing), but they are others (ballum, pyrogenes, etc.) more rarely identified but present.
* Habitat:
These bacterias grow in polluted habitats : stagnant or turbulent waters.
The germ survival is all the easier that the water is fresh, muddy, warm (about 20°C) and slightly alkaline.
leptospires may survive so, out of their host, during days, weeks.
They are killed by dryness, soaps, disinfectants, or a heat of 50°C during at least 5 minutes.
They survive ony few hours in salted water.
Leptospires spread in the environment which reach the mucous membranes of a possible host, or which are swallowed, induce then the disease.
* Hosts:
They are mainly the rodents (rats), dogs, pigs, horses and cows, and extremely rarely: cats, birds, reptiles and fishes.
Dogs get leptospirosis by direct contact with soil, or water contaminated by infected urine, or eating infected animal wastes. The carrying animal recovers from the disease, but continue to carry and excrete leptospires for months, even years.
Human infection is indirect, by contact between skin, mucous membranes and infected animal urines polluted waters (80% of the cases), or direct, by bites, or manipulation of contaminated animal tissues, or contaminated food or water ingestion. The direct contamination between men is extremely rare. Man contamination by polluted water will be all the more easy as his teguments have gone soft by the water and as his skin is injuried with tiny cutaneous cuts.
Anyone in regular contact with fresh water or with contamination is at risk, from sportsmen (hikers, bikers, 4x4, divers, canyonning, fishermen, hunters, etc...) to professionnals (farmers, stockbreeders, abattoirs staffs, butchers, tanners, sewer workers, dustmen, road maintenance staffs, veterinarians, animal keepers, Forestry and Wildlife agents, plumbers, purification bassin agents, scuba divers, First Aids staffs, gaz and electricity agents).
Incubation lasts in 4 to 14 days.
The disease must be treated as soon as possible to avoid the fearsome complications.
On dogs:
It is defined at start by:
Then come the serious forms, for which recovery is rare:
On man:
Spirochetes come in by mucous tissues and/or skin, mouth, nose, eyes injuries and migrate in the body's different organs.
The disease shows itself in a way quite similar to the dog : from flu-like condition to meningitis or kidney failure.
It appears more often in men than in women.
The diagnosis is difficult because of the pseudo-flu look at start, polymorphic after and if the risk is not evoked. An apparent remission, before a strong come back the 15th day after the first attack, would point it out.
There are:
Serious forms leading to a fatal evolution represents from 3 to 5 % of the cases.
Invasion period is shorter (between 7 and 12 days).
The icterus is usually intense with:
Death may then occur within a multi-visceral clinical failure picture.
Death is rare if the jaundice is not noticed.
In mild cases, the flu-like state disappears by itself within two or three weeks, which induces that the observed case number is under-evaluated. .
It requires, for man,an hospitalization - even a resuscitation service - due to the renal risk ( kidney failure for 25 % of the cases )
For both, antibiotherapy ( penicilin, amoxicillin ) is efficient only if given early, that is to say before haemorrhagic signs occurs. (after the 5th day, it is hazardous) It reduces the complication risk but changes few the evolution.
Convalescence is long but generally without aftereffects.
Ocular complications come later ( 1 to 5 months ) and recovery occurs generally without aftereffects.
* Vaccinate?
Dog:
It is dogs very interest to vaccine. Depending on the risk of your area, do plan 1 to 2 vaccines by year, for the whole life of your compagnon.
Vaccines are available at veterinarians and protect agaist some serotypes.
Vaccines against the L.grippotyphosa and L.pomona serotypes, have not yet been finalized. Producers works today to include a protection against these new forms.
Dogs (vaccined or not) owners would have to think about Leptospirosis each time where a flu-like condition occurs and act accordingly (antibiotics).
Man:
The vaccine finalized by the Institut Pasteur is the only one available at present in France. This vaccine date of 1974. It has been developped on the demand of the professional organism Égoutiers de la ville de Paris (Paris sewer workers) for whom it had become required in 1976.
The vaccination requires three injections, one the first day, the second 15 days later and the third 6 months later with a booster dose each two years. It is efficient against Leptospira interrogans hemorragiae for which it have two serotypes which are found exclusively in rats.
It is estimated that only 17 % of professionnals at risk are vaccinated.
Well tolerated vaccination gives them a little protection.
* * Can it be suggested against the leptospirosis of ours rivers?
The vaccination against one or two serotypes does not allow to obtain a protection against the 23 polynesian serotypes and even less against the 100 to 200 known serotypes in the world. This vaccination wears a probability of effectiveness of about 40%, but Leptospira interrogans hemorragiae represents the majority of the serious forms.
* Can we suggest a vaccination which doesn't reduce totally the risk?
There is an efficient treatment, the antibiotherapy, under the condition that it must be provided early.
Because, for some being vaccinated and believing to be protected, trying to cure too late would be a drama, leading the development of a serious form.
As it is, anti-leptospirosis vaccination may not be recommended as a way of prevention.
Consequently, it is fundamental:
* * Other prevention forms:
Precautions of elementary common sense reduce risks: