Severe Leptospirosis in Hospitalized Patients, Guadeloupe

We evaluated prognostic factors for leptospirosis in 168 consecutive hospitalized patients in Guadeloupe. Factors independently associated with severity included chronic hypertension or chronic alcoholism, late initiation of antibacterial therapy, abnormal chest auscultation results, icterus, oligoanuria, disorders of consciousness, elevated aspartate aminotransferase levels, hyperamylasemia, and Leptospira interrogans serovar Icterohemorrhagiae.

L eptospirosis is a reemerging infectious disease in tropical and subtropical regions (1). In Guadeloupe, it has long been a major public health concern. Its incidence rate was ≈5.5/100,000 inhabitants per year from 1991 through 2002. Since 2003, this rate has greatly increased, peaking at 41.2/100,000 inhabitants in 2004 (2, 3). The clinical features of leptospirosis vary and may progress to multiorgan failure and death (4). Initial clinical symptoms and laboratory test results associated with severe forms remain unclear. In this study, we focused on severe forms and determined prognostic factors that may help physicians in the early management of leptospirosis. We also characterized reservoir hosts by identifying the serovars of infecting strains. These fi ndings will help establish appropriate control and prevention measures.

The Study
This study was conducted in the hospital of Pointe-à-Pitre (1,100 beds), a tertiary referral center for Guadeloupe and neighboring islands. The ethical committee of the hospital approved the study. All consecutive patients hospital-ized from January 2003 and through December 2004 with confi rmed leptospirosis were included; patients admitted to Guadeloupe's other hospital (200 beds) were excluded. Leptospirosis was confi rmed if 1 blood culture yielded Lesptospira spp. or if specifi c antibodies were detected with either a single titer of >400 with the microscopic agglutination test (MAT) and an in-house enzyme immunoassay (EIA) with an immunoglobulin (Ig) M titer >400 (5) or at least a 4-fold increase in the MAT titer between the acute and convalescent phases. Cases were considered severe if dialysis (in case of oliguria) or mechanical ventilation was required or if the patient died. Leptospira serovars were isolated and identifi ed as previously described (3). Epidemiologic, clinical, and laboratory data were collected retrospectively from medical records taken at patient's admission. Data were analyzed by using Epi Info (Centers for Disease Control and Prevention, Atlanta, GA, USA). A multiple stepwise logistic regression analysis (SPSS, Chicago, IL, USA) was performed for variables with a p value <0.2.
During the 2-year period, leptospirosis was diagnosed in 168 hospitalized patients. A total of 132 case-patients had specifi c antibodies (49 had a single MAT titer >400 and EIA IgM titer >400, and 83 showed a 4-fold increase in the MAT titer in paired serum samples); 36 cases were confi rmed only by culture. Of the 132 case-patients testing positive for antibody, 19 were also positive for bacterial culture. All but 2 case-patients were residents of Guadeloupe; the other 2 were a tourist from Paris and a resident of the Dominica. The ethnic distribution of the study population was similar to that of the Guadeloupean population.
Univariate analysis showed that, after stratifi cation for sex, severity was associated with age for women but not for men. Neither occupation (farming, livestock farming, construction, and gardening) nor contact with swine, cattle, or rodents was linked to severity (Table 1). Nine host-related factors (listed in order of decreasing odds ratio) remained independently associated with severity in the multivariate analysis: history of chronic hypertension, hyperamylasemia, history of chronic alcoholism, abnormalities at chest aus- cultation, oligoanuria, late initiation (>10 days after onset of symptoms) of antibacterial therapy, elevated aspartate aminotransferase levels, consciousness disorders, and icterus. Chronic alcoholism was linked to death (p<0.01). The L. interrogans serovar Icterohemorrhagiae was isolated in 75% of severe cases, but in only 38% of nonsevere cases, and was independently associated with severity.

Conclusions
The potential correlation between disease severity and Leptospira serovar remains a matter of debate. The L. interrogans serovars Icterohemorrhagiae, Canicola, and Australis have been linked to severity and multiorgan failure (6)(7)(8), but other studies did not confi rm any link between serovar and outcome (9)(10)(11). L. Icterohemorrhagiae was clearly linked to disease severity. Therefore, a diagnostic test specifi cally detecting this serovar at an early stage of disease could help in the management of leptospirosis in patients in Guadeloupe. We confi rmed that the L. borgpetersenii serovars Arborea and Castellonis, rarely isolated elsewhere, are highly prevalent in Guadeloupe (3,12). Taken together, they are the second most prevalent serovars after Icterohemorrhagiae. Notably, the serogroup Ballum, comprising the serovars Arborea and Castellonis, also is one of the main serogroups associated with human infections in Barbados (9). The serovar Arborea has been associated with mice, particularly in Barbados (1,13). In Guadeloupe, this serovar has been isolated from mice and rats, and the serovars Icterohemorrhagiae and Bogvere have been isolated from rats (3; V. Michelle, pers. comm.). Thus, rodent populations may be the main source of Leptospira spp. in Guadeloupe. Further animal studies are needed to establish the nature of these Leptospira reservoirs. Chronic hypertension has not previously been found to predict poor prognosis for leptospirosis. Here, we found it to be the strongest risk factor for severe disease. Whether patients with histories of chronic hypertension are especially susceptible remains to be confi rmed.
In our series of patients, acute hepatitis and pancreatitis were severe complications of leptospirosis in those with chronic alcoholism; chronic alcoholism itself was an independent indicator of poor prognosis. These results are consistent with fi ndings from other studies conducted in La Réunion, another French overseas territory, and in continental France (14,15).
Patients with chronic hypertension or chronic alcoholism, late initiation of antibacterial therapy, consciousness disorders, abnormal features at chest auscultation, oligoanuria, jaundice, hyperamylasemia, or high aspartate aminotransferase levels may benefi t from early intensive and specifi c management. The predominance of the Icterohemorrhagiae serovar, linked to severe disease, and of the Arborea and the Castellonis serovars highlights the need for rodent control to reduce the effects of leptospirosis in Guadeloupe.