Human Leptospirosis Seroprevalence in the Azores archipelago (Portugal): an update (2004 - 2011)

Translated title of the contribution: Seroprevalência da Leptospirose Humana no arquipélago dos açores (Portugal): uma atualização (2004-2011)

Teresa Carreira, Mónica Nunes, Maria Luísa Vieira

Research output: Contribution to conferencePosterpeer-review


Eurolept 2012 Poster presentations
pp 15
Carreira T.1,2, Nunes M.1,2, Vieira M. LY 1.2
1 Unidade de Ensino e Jnvestiga9ao de Microbiologia Medica, Grupo de Leptospirose e Borreliose de Lyme, Instituto de
Higiene e Medicina Tropical (JHMT), Universidade Nova de Lisboa (UNL), Lisboa, Portugal
2 Centro de Recursos Microbiol6gicos, Faculdade de Ciencias e Tecnologia, UNL, Lisboa, Portugal

Since the early 90\'s that Azores Archipelago (Portugal), namely Sao Miguel and Terceira islands have been considered an endemic area for leptospirosis. High precipitation and moderate temperature,

together with wide densities of rodents, provides an extensive dissemination of these spirochetes allowing their survival in environment. In Portugal, the first isolation of Weil acutes agent disease was obtained in 1931 . However, regular research on human leptospirosis started in the 1980s, becoming a notifiable disease in 1987. In Portugal, the number of official reported cases has been low when compared with other countries. In fact, leptospirosis is still not always notified nor even diagnosed due to its often unspecific clinical appearance and difficult laboratorial diagnosis. This study aimed to evaluate the current trend of leptospirosis in Azores, established on seroprevalence registered at the Leptospirosis Lab (IHMT, UNL) databases, during the last eight years. Between 2004 and 2011, a total of I 028 human sera (563d' and 84~) from 647 patients with leptospirosis clinical suspicion, were analyzed during the referred period, by the Microscopic Agglutination Test (MAT) in order to detect anti-Leptospira
interrogans sensu Jato (s.l.) antibodies. In the eight-year study period, 225 (3J%) symptomatic patients were confirmed to have a currentLepto~pira infection. The annual distribution9fleptospirosis cases, showed an average of 28 cases per year, with higher frequency in males (93% ). Middle age adults (21-50 years) were most frequently infected (64%); and 29% corresponds to a·population with
more than 50 years old. Leptospirosis has been confinned as a public health probli;m in Portugal, particularly in Azores islands. This retrospective study revealed a marked decrease of-cases; however, the annual incidence rate increased (15/100 000 population) when compared with the ,incidence re,veaJ~d
in a previous study (11.1/100 000), nevertheless, it is noted the absence of fatalities fo that period. The major infecting serogroup is Icterohaemorrhagiae (28%) followed by Ballum ser9grcn1p -(l 5%), this distribution is coincident with the previous data known in these islands. According to the-present series study, leptospirosis continues predominantly affecting active adult men due to their professional and leisure activities. Finally, it is important to note that these results show an increasing attention given to this zoonosis for the population and Health care. These improvements results from the active surveillance
began with the project ,,Epidemiology and Control of Leptospirosis in Azores" developed between 2004-2008, under USA Scientific-Cooperative Agreement No. 5 8-400] -3-F 185. Nevertheless, we assume that it is necessary to improve diagnostic methods, including molecular techniques in order to obtain an early diagnosis, anticipating the MAT results and contributing to disease control.
Translated title of the contributionSeroprevalência da Leptospirose Humana no arquipélago dos açores (Portugal): uma atualização (2004-2011)
Original languageMultiple languages
Number of pages94
Publication statusPublished - 31 May 2012
EventEuropean Meeting of Leptospirosis organised by ELS (european Leptospirosis Society: Eurolept 2012 - Dubrovnik, Croatia
Duration: 31 May 20122 Jun 2012


ConferenceEuropean Meeting of Leptospirosis organised by ELS (european Leptospirosis Society
Abbreviated titleELS


  • Human leptospirosis
  • Seroprevalence
  • Azores archipelago
  • Portugal
  • Epidemiology


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