title: Large-scale application of highly-diluted bacteria for Leptospirosis epidemic control.
abstract: BACKGROUND
  Leptospirosis is a zoonotic disease of major importance in the tropics where the incidence peaks in rainy seasons. Natural disasters represent a big challenge to Leptospirosis prevention strategies especially in endemic regions. Vaccination is an effective option but of reduced effectiveness in emergency situations. Homeoprophylactic interventions might help to control epidemics by using highly-diluted pathogens to induce protection in a short time scale. We report the results of a very large-scale homeoprophylaxis (HP) intervention against Leptospirosis in a dangerous epidemic situation in three provinces of Cuba in 2007.
  
  
  METHODS
  Forecast models were used to estimate possible trends of disease incidence. A homeoprophylactic formulation was prepared from dilutions of four circulating strains of Leptospirosis. This formulation was administered orally to 2.3 million persons at high risk in an epidemic in a region affected by natural disasters. The data from surveillance were used to measure the impact of the intervention by comparing with historical trends and non-intervention regions.
  
  
  RESULTS
  After the homeoprophylactic intervention a significant decrease of the disease incidence was observed in the intervention regions. No such modifications were observed in non-intervention regions. In the intervention region the incidence of Leptospirosis fell below the historic median. This observation was independent of rainfall.
  
  
  CONCLUSIONS
  The homeoprophylactic approach was associated with a large reduction of disease incidence and control of the epidemic. The results suggest the use of HP as a feasible tool for epidemic control, further research is warranted.
authors.affiliation: Finlay Institute, Ave. 27, La Lisa, Havana City, Cuba. gbracho@finlay.edu.cu
authors.forename: Gustavo
authors.initials: G
authors.lastname: Bracho
authors.forename: Enrique
authors.initials: E
authors.lastname: Varela
authors.forename: Rolando
authors.initials: R
authors.lastname: Fernández
authors.forename: Barbara
authors.initials: B
authors.lastname: Ordaz
authors.forename: Natalia
authors.initials: N
authors.lastname: Marzoa
authors.forename: Jorge
authors.initials: J
authors.lastname: Menéndez
authors.forename: Luis
authors.initials: L
authors.lastname: García
authors.forename: Esperanza
authors.initials: E
authors.lastname: Gilling
authors.forename: Richard
authors.initials: R
authors.lastname: Leyva
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Rufín
authors.forename: Rubén
authors.initials: R
authors.lastname: de la Torre
authors.forename: Rosa L
authors.initials: RL
authors.lastname: Solis
authors.forename: Niurka
authors.initials: N
authors.lastname: Batista
authors.forename: Reinier
authors.initials: R
authors.lastname: Borrero
authors.forename: Concepción
authors.initials: C
authors.lastname: Campa
mesh_terms: D000284:Administration, Oral; D001428:Bacterial Vaccines / Q000008:administration & dosage*; D015331:Cohort Studies; D003462:Cuba / Q000453:epidemiology; D004196:Disease Outbreaks / Q000517:prevention & control* / Q000706:statistics & numerical data; D006705:Homeopathy / Q000379:methods*; D006801:Humans; D015994:Incidence; D007919:Leptospira; D007922:Leptospirosis / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control*; D011159:Population Surveillance; D012621:Seasons; D012997:Solvents; D016896:Treatment Outcome
chemical_list: D001428:Bacterial Vaccines; D012997:Solvents