Babesia gibsoni (B. gibsoni) is a protozoal parasitic disease commonly diagnosed in dogs seized in dogfighting investigations. This study compared the prevalence of B. gibsoni among two groups of pit bull-type dogs: those involved in confirmed cases of organized dogfighting and those with no known history of involvement in organized fighting.
This study is unique from any previous related studies in the following ways:
The total sample size was larger (>1000 dogs) than any previous study.
This is the first study to compare pit bulls to pit bulls instead of pit bulls to other breeds of dogs.
The fighting group included only dogs from closed criminal cases in which there was a guilty plea or conviction of dogfighting or dogfighting-related charges (i.e., dogfighting cases as confirmed by the criminal justice system).
This conservative classification system was used to examine the association between babesia infection and organized dogfighting from a criminal prosecution perspective.
Because of the high prevalence of B. gibsoni in pit bull-type dogs, it is the ASPCA's standard protocol to test all pit bull-type dogs that are the subject of criminal investigations for B. gibsoni regardless of whether there is an allegation of dogfighting. ASPCA researchers reviewed medical records from internal animal cruelty and dogfighting cases in the United States from 2011 to 2019.
Dogs identified as pit bull-type during an intake examination and had a recorded Babesia gibsoni test result were included in the study comparison groups. The “fighting” group consisted of dogs associated with closed criminal cases in which the dog owner pleaded guilty to or was convicted of dogfighting or conspiracy to commit dogfighting. Dogfighting cases in which the outcome was still pending were excluded from analysis, as were cases in which charges relating to dogfighting were dismissed; there were no cases resulting in acquittal.
The “non-fighting” group consisted of pit bull-type dogs associated with criminal animal cruelty cases that did not involve allegations of organized dogfighting.
Researchers analyzed data using descriptive statistics, chi-square tests, Wilcoxon rank-sum tests, and Spearman correlations for tests of association among ordinal variables and other non-normally-distributed variables, and logistic regression. Read the full study for a thorough explanation of the research methodology.
The final sample consisted of 1709 dogs, of which 1051 were associated with organized dogfighting (fighting group), and 658 were associated with animal cruelty cases not known to involve dogfighting (non-fighting group). Dogs originated from 27 dogfighting cases, 482 non-fighting animal cruelty cases, and 1 case involving both dogs associated with fighting and dogs not associated with fighting.
The results showed:
The prevalence of B. gibsoni was significantly higher in pit bull-type dogs associated with organized dogfighting (26%) versus those with no known association with fighting (2%).
A dog infected with B. gibsoni had 21 times higher odds of being from a dogfighting case than an uninfected dog.
At the case level, in groups of dogs where the infection rate was 25% or above, it was more likely than not that the case was a confirmed dogfighting case.
The high prevalence of B. gibsoni infection in pit bull-type dogs is not explicitly related to breed but to the dogs being victims of dogfighting.