Host species and age-specific variation on Hepatozoon prevalence and its effect on body condition in two Neotropical crocodiles

Many populations of species belonging to the order Crocodilia are
threatened because of habitat loss and degradation, parasitic diseases,
illegal trafficking, and indiscriminate hunting. Although several studies
have revealed that crocodiles, caimans, and alligators are frequently
infected by Hepatozoon species, the results from studies
exploring the costs of these apicomplexan parasites on their reptilian
hosts are still scarce and with inconclusive results. Here, we molecularly
assessed the prevalence and genetic diversity of Hepatozoon spp. to
explore the differences in body condition in captive individuals of two
species of neotropical crocodilians with conservation threats, the
spectacled caiman (Caiman crocodilus) and the American crocodile
(Crocodylus acutus). Fourteen percent of spectacled caimans were infected
by Hepatozoon caimani, whereas no American crocodiles showed infection.
The prevalence of Hepatozoon in spectacled alligators varied along age,
where subadult individuals were the most frequently parasitized.
Surprisingly, the body condition of infected individuals was significantly
higher than the body condition of uninfected spectacled caimans, which
suggests greater negative effects of the infection in individuals with
poor quality. Also, the body condition of subadult individuals was
significantly higher than the body condition of juveniles of both
alligator species, likely reflecting differences in the occupancy of
habitats with higher resource abundance or variations in the nutritional
values of the diet between these age classes. These outcomes provide
valuable information on disease ecology for developing conservation
strategies and the management conservation of wildlife populations of
these species.