Ryan HillLeptospirosis Infection in Nicaraguan Dogs



Dogs attending our clinic in Mérida, Nicaragua, will be tested to determine if they have current Leptospirosis infections. They will also be tested to determine Lepto titers. A survey addressing potential Lepto infections will be given to the dog owners to discover if there is a link between infections in dogs and humans. In short, we hope to determine the prevalence of Leptospirosis infection in the Mérida dog population, and determine if there is any potential association with Leptospirosis infection in the human population.



            We hope to show that Leptospirosis is a prevalent disease in the dogs of the Mérida community, and a possible source of infection for the people. If we receive the necessary data, we hope to prove that the strains infecting the dogs and the people are the same, drawing an even stronger link between the people and dog infections.


Experimental procedures 

Dogs from the community of Mérida, Nicaragua will be voluntarily brought to our temporary clinic, where we perform a physical exam, administer dewormer and flea/tick preventative, and spay/neuter them if desired. These dogs are of various ages and of both sexes and are generally kept as pets by the community members.

            The prevalence of Leptospirosis in Mérida is not known, but during the outbreak of 1995, it was shown to be 44%. If prevalence is estimated to be 50%, a sample size of 166 is needed to have 99% confidence and a desired absolute precision of +/- 10% (Thrushfield, see table below). Because of the increased risk of damage and loss to experimental samples during transport to the United States, it is best to collect more than the required amount, so we will aim for the collection of 200 samples.

Blood samples are obtained from all dogs presented at the clinic, and are used for things such as determining PCV, platelet counts, and blood smears. The serum from these samples will be collected for this study at this time.

Serum will be transported back to Oregon State University, where it will be analyzed via PCR and MAT. PCR testing will be done by the PI to determine if the dogs are acutely infected with Lepto. MAT will be done by the Bacteriology Lab at OSU to determine titer levels, showing if the dogs have been exposed in the past. MAT will also provide information about which strains of Lepto are causing any infections.           

Additionally, an optional survey will be administered to the owners bringing their dogs to the clinic, which will ask questions relating to their own potential Leptospirosis infections, such as any history of urinary tract pain, nature of interactions with dogs and other animals, source of drinking water, other times spent in water, and general location of residence.

These two sources: serum data from the dogs and survey data from the humans, will be analyzed and compared to determine if there are Lepto infections in either or both of the humans and the dogs, and the plausibility that they are infecting one another.