Immunohematological features of free-living Alouatta belzebul (Linnaeus, 1766) red-handed howler monkeys in the Eastern Amazon

• Published in: Primates Vol. 63; no. 6; pp. 671 - 682
• Main Authors: Guimarães, Victor Yunes, Zanoni, Diogo Sousa, Alves, Carlos Eduardo Fonseca, Amorim, Reneé Laufer, Takahira, Regina Kiomi
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.11.2022; Springer Nature B.V
• Subjects: Alouatta belzebul; Animal Ecology; Anthropogenic factors; Antigens; Behavioral Sciences; Biomedical and Life Sciences; CD3 antigen; Dam construction; Deforestation; Dry season; Endangered species; Eosinophils; Evolutionary Biology; Hematology; Human influences; Immune response; Immunocytochemistry; Leukocytes (eosinophilic); Life Sciences; Lymphocytes; Lymphocytes B; Lymphocytes T; Monkeys; Monocytes; Original Article; Pax5 protein; Population studies; Threatened species; Zoology; Complete blood count; Neotropical primate; Immunocytochemistry; Lymphocyte subset
• ISSN: 0032-8332; 1610-7365
• DOI: 10.1007/s10329-022-01009-w

The red-handed howler monkey ( Alouatta belzebul ) is one of the 35 threatened Brazilian primate species found in two highly endangered Brazilian biomes. Their Amazonian native populations have been declining due to exponential deforestation associated with human activities, especially the construction of dams. The studied population ( n  = 27) was located in the Belo Monte dam Area of Influence. For the first time, we presented hematological parameters and the basic profile of T (CD3) and B (BSAP PAX5) cells by immunocytochemistry. The results supported the hypothesis that the immuno-hematological profile is influenced by sex, age, and season. Eosinophils were significantly higher in females ( p  = 0.03), monocytes statistically greater in juveniles ( p  = 0.04), and total plasma protein increased significantly ( p  > 0.001) during the dry season. Furthermore, adults showed a statistically higher average absolute number of B lymphocytes than young individuals ( p  = 0.03), in contrast to T lymphocytes. Even without knowing the full history of antigenic exposure, these results not only contribute to elucidating the boundaries between health and disease but may help lay the groundwork for future research into the effects of anthropogenic stress on immune activation.