Health evaluation of Brazilian sirenians (Trichechus inunguis and Trichechus manatus manatus)

Abstract

Sirenians are monogastric herbivorous aquatic mammals of tropical and subtropical distribution, with occurrence of two species in Brazil: Trichechus inunguis or Amazonian manatee, occurring throughout the Amazon Basin, and Trichechus manatus manatus or Antillean manatee, which inhabits coastal systems and tropical and subtropical rivers in the area of the West Atlantic from the Bahamas to Brazil. Both species are classified as Vulnerable by the IUCN Red List and listed in the "Official National List of Endangered Species of Wildlife' as endangered. Threats to the species include those related to anthropic pressures, such as hunting, by catch in fishing nets and habitat reduction, as well as the occurrence of pathogenic microorganism infections. Transmissible diseases of viral, bacterial, parasitic and fungal origin have been described in a great variety of aquatic mammal's species in several geographical locations, with the potential to cause severe clinical conditions and population decline. However, information regarding the occurrence of these diseases in sirenians is still scarce in Brazil. Due to the urgency in obtaining systematized and extensive information about the Amazonian manatee and Antillean manatee, in order to increase their wild populations in Brazil, the National Action Plan for the Conservation of the Sirenians (Sirenians PAN) was elaborated by the Chico Mendes Institute for Biodiversity Conservation (ICMBio), aiming to obtain systematized sanitary information from these two unique species of aquatic mammals as a way to guarantee the health of animals kept in captivity in rehabilitation centers and also free-living animals, whether they are reintroduced or not. Therefore, the objective of this proposal is to carry out a diagnostic screening to investigate the occurrence of pathogenic microorganisms in sirenians of T. manatus manatus and T. inunguis species from captivity and free-living, from maintenance, rehabilitation and reintroduction in nature programs, in the Northeast and Northern regions of Brazil. Blood, serum, swabs and feces samples will be obtained from live animals, as well as tissue fragments collected in the case of animals that have died, to perform investigation of infections by the following pathogens: Brucella, Mycobacterium, Leptospira, Campylobacter, Helicobacter, paramyxovirus, hepatitis E virus, microsporidia, Sarcocystidae family protozoans, Giardia, Cryptoporidium and other intestinal parasites. Serological, microbiological and molecular methods and coproparasitological tests will be used to investigate the mentioned pathogens. The molecular tests will allow the detection of a wide variety of agents within a group or taxonomic level of pathogens, and genotyping will be performed to obtain accurate information about the genus or species investigated. The analysis of the results will be based on the calculation of the frequency of occurrence of infections caused by the microorganisms analyzed. These results may also collaborate in the establishment of a protocol for sanitary monitoring of wild and captivity populations, assisting in the achievement of other goals established in the Sirenians PAN, which aim to create an information and monitoring system for captivity sirenians in Brazil, release of rehabilitated marine manatees and conduct monitoring of reintroduced animals. (AU)