Introduction
In 1998, the number of leptospirosis cases decreased considering the two previous years. 684 cases were recorded on the whole (Continental France and French Overseas Territories). This decrease concerns both Continental France (269 cases as compared to 314 and 434 in 1997 and 1996 respectively) and Overseas Territories (408 as compared to 585 and 569 in 1997 and 1996 respectively(1,2).
Interpretation of the epidemiological data
These two last years, the number of cases decreased of 20% per year as compared to the previous year. However the score remains close to the mean one of the ten last years, due to the high number of detected cases in 1997 and mainly 1996 (1).
On the seasonnal point of view, the maximum of endemicity is, as usual, observed in the 2nd part of the year, but the contrast is low, in particular no clear "peak" is noticed(Table 1).
Concerning the serogroup repartition, the Icterohaemorrhagiae rate represents less than the third of the whole, which is low. In contrast, Grippotyphosa (20%) is rather normal and closely followed by Australis and Panama. It is noticeable that Australis, Bataviae and Panama are well represented at the end of spring, Icterohaemorrhagiae and Sejroe in sumner/autumn and Grippotyphosa in autumn/winter. This succession explains the low seasonnal contrast among the cases detected in 1998 (Table 1) (Table 7).
The geographical distribution shows atypical and low rates in some usually endemicity. Champagne Ardennes, Aquitaine* and Basse Normandie get the less low rates although they do not exceed 1/100000 inhabitants. Poitou Charentes, Pays de Loire and Bretagne come then by decreasing range of order (0.7-0.8/100000). Unexpectedly, Franche Comte records this year less than 0.4 100000 (Table 7).
Regional importance of the serogroup shows that Grippotyphosa predominates in Bretagne, Basse Normandie Pays de Loire and Charente Maritime regions which this year reached more or less normal rates. In contrast, Aquitaine* which, usually as the whole Western part of France (atlantical Coast), exhibits many Grippotyphosa cases, this year, is characterized by both a rate inferior to 1/100000 and a predominance of Icterohaemorrhagiae (Table 7).
In Overseas Territories, the decreasing number of cases is almost exclusively due to the decreasing in New Caledonia (the 1998 (Table 8)score is only half of the 1997 one (Table 8bis)). In 1997, a hurricane at the beginning of the year and then a quite rainy season from May to July were responsible for a double "peak" of cases
In Guyane (97300), the number of positive diagnoses decreased each year for 3 years (1, 2): 18 and 11 in 1996 and 1997 respactively. The 6 cases of1998 will not be reported as a Table.
In opposition, in Mayotte in Indian Ocean which now got a specific postal zip code:97600, the cases, still detected by la Reunion (Dr MICHAULT) will be reported as a separate Table (Table 5) distinct from the la Reunion one(Table 2).
The other "DOM-TOM" (French Overseas Territories): exhibit normal and usual rates: Northern Atlantic Tropiques (Table 3 Table 4), in winter, from November to March; Tahiti (Table 6) and New-Caledonia, South Pacific Tropiques, during spring: March to July for the former and all the second part of the year for the later one ; la Reunion (Table 2) and Mayotte (Table 5); Southern Indian Tropiques, all the second part of the year too.
In each "DOM-TOM", with the exception of Mayotte(Table 5), Icterohaemorrhagiae largely predominates (La Reunion(Table 2), La Martinique (Table 4) or less (Tahiti (Table 6), New-Caledonia (Table 8)). A second serogroupe is noticeable in Tahiti : Australis(Table 6), and two other ones in New Caledonia : Pyrogenes and Canicola(Table 8). Elsewhere, the situation is more schematic : with the excception of Canicola, overspread, other serogroups are scarce. However, in Mayotte, etiological serogroups , for a still unknown reason, are more diverse: Grippotyphosa, Pyrogenes and even Sejroe are more present than Icterohaemorrhagiae (Table 5).
* In what concerns Aquitaine, this year the number of cases appears to be overestimated because the recruitment of a big Laboratory which does not make available the epidemiological informations has been enlarged on a national scale and not only regional one.
1. Baranton G., Postic D. 1997. Contribution a la surveillance epidemiologique de la leptospirose en France en 1996. http://www.pasteur.fr/Bio/Leptospira/(textcnr1996.html)
2. Baranton G., Postic D. 1998. Contribution a la surveillance epidemiologique de la leptospirose en France en 1996. http://www.pasteur.fr/Bio/Leptospira/(textcnr1997.html)
3.4. Publications from the "C.N.R. des Leptospires" in 1998
. Publications related to expertise field
BARANTON G., POSTIC D. (1998) Borrelia.
BARANTON G., PEROLAT P. (1998) Les leptospires. in Traite de Microbiologie Clinique, sous la direction de A. EYQUEM, J. ALOUF, L. MONTAGNIER, Edit. PICCIN, Padova, Italie, 1998, 1 vol. 1596 pages, 697-704, 705-712.
BARANTON G. (1998) Vaccination antileptospirose. Vaccin contre la borreliose de Lyme. in Manuel des Vaccinations et d'Immunoprevention, sous la direction de A. EYQUEM, J. ALOUF, A. CHIPPAUX, Edit. PICCIN, Padova, Italie, 1998, 1 vol. 359 pages, 148-151, 151-155.
PEROLAT P., CHAPPEL R.J., ADLER B., BARANTON G., BULACH D.M., BILLINGHURST M.L., LETOCART M., MERIEN F., SERRANO M.S. (1998) Leptospira fainei sp.nov. isolated from pigs in Australia. Int. J. Syst. Bacteriol., 48 (part 3), 851-858.
CAO T.B. Van,THUY T.T. Nguyen, SAN H. Ngo, HIEN T. Tran, BARANTON G., PEROLAT P. (1998) Human leptospirosis in the Mekong delta, Viet Nam. Trans. Roy. Soc. Trop. Med. Hyg., 92, 625-628.
YERSIN C., BOVET P., MERIEN F., WONG T., PANOWSKY J., PEROLAT P. (1998) Human leptospirosis in the Seychelles (Indian Ocean) : a population-based study. Amer. J. Trop. Med. Hyg., 59, (6), 933-940.
. Publications related to research activity:
MARTI RAS N., POSTIC D., BARANTON G. (1998) Diversite genomique chez Borrelia burgdorferi sensu lato, une caracteristique partagee de part et d'autre de l'Atlantique. Med. Mal. Infect., 28 (N¡ special 7e CEMI), 398-399.
POSTIC D., MARTI RAS N., LANE R.S., HENDSON M., BARANTON G. (1998) Expanded diversity among Californian Borrelia isolates and description of Borrelia bissettii sp. nov. (formerly Borrelia Group DN127). J. Clin. Microbiol., 36, (12), 3497-3504.
MERIEN F., TRUCCOLO J., ROUGIER Y., BARANTON G., PEROLAT P. 1998) In vivo apoptosis of hepatocytes in guinea pigs infected with Leptospira interrogans serovar icterohaemorrhagiae. FEMS Microbiol. Letters, 169, (1), 95-102.
BARANTON G., MARTI RAS N., POSTIC D. (1998) Borrelia burgdorferi, taxonomie, pouvoir pathogène et expansion. Ann. Med. Interne, 149, (7), 455-458.
BARANTON G., MARTI RAS N., POSTIC D. (1998) Molecular epidemiology of the aetiological agents of Lyme borreliosis. Wien. Klin. Wochenschr., 110/24, 850-855.
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