Evaluation of Parasitological and Immunological Techniques in the Diagnosis of Cryptosporidium and Giardia in Aquatic Mammals - Abstract
Infections caused by Cryptosporidium and Giardia are among the main gastro enteric diseases affecting a large number of animals and humans. Oftentimes the disease is asymptomatic, which may render the diagnosis involving aquatic mammals difficult. The aim of this study was to evaluate the use of an immunological technique with parasitological methods in the diagnosis of Cryptosporidium and Giardia in aquatic mammals. A total of 553 fecal samples and intestinal contents of mustelids, cetaceans and sirenians were submitted to laboratory processing. Cryptosporidium oocysts were identified with Kinyoun’s technique. Giardia cysts were identified using the centrifugation-flotation method. All samples underwent immunological tests through direct immunofluorescent antibody (DFA). The Kappa Index k was used to measure the agreement between techniques used for the detection of each parasite addressed in this study. Sensitivity, specificity, real prevalence, estimated prevalence, positive predictive value, negative predictive value, correct classification and incorrect classification were evaluated. Cryptosporidium were found in Pteronurabrasiliensis [10/24 (41.66%)], Trichechus inunguis [22/131 (16.79%), Lontra longicaudis
[48/314 (15.28%)], Trichechus manatus [04/29 (13.79%)] and Sotalia guianensis [03/31 (9.67%)]. Giardia was identified in Kogia breviceps [01/01 (100%)], Pteronurabrasiliensis [07/24 (29.16%)], Kogia sima [01/04 (25%)], Trichechus manatus [04/29 (13.79%)], Sotalia guianensis [03/31 (9.67%)], Lontra longicaudis [30/314 (9.55%)] and Trichechusinunguis [05/131 (3.81%)]. The k value for the diagnosis of Cryptosporidium was 0.86; for Giardia cysts the k-value was 0.27. Therefore, the direct immunofluorescent technique demonstrated greater sensitivity both in the diagnosis of Cryptosporidium and Giardiawhere the combination of more than one laboratory technique is recommended.