Vascular, cardiac, and renal lesions attributed to primary systemic hypertension in western pygmy marmosets (Cebuella pygmaea)

In a retrospective study of a western pygmy marmoset ( Cebuella pygmaea) colony, postmortem examination of 1/8 juvenile and 29/47 adult animals identified vascular, cardiac, and renal lesions consistent with systemic hypertension. This included frequent renal arteriolar hypertrophy, hyaline and proliferative arteriolosclerosis, fibrinoid necrosis of arterioles, glomerulosclerosis, and nephrosclerosis. Affected animals ranged from 0.6 to 12 years of age (mean 6 years) and had an observed male predominance. Genealogical relatedness was evident in several breeding pairs and spanned multiple generations. Concurrent cardiac and renal disease was commonly identified, although frequently subclinical, and both were important causes of morbidity and mortality in affected animals. Cardiomegaly and hypertrophy were typical features and were accompanied by left atrial thrombosis in 10 animals. Signs of heart failure included chronic pulmonary edema in 20 cases and body cavity effusions in 17. In the kidneys, 19 cases had glomerular disease and hypertensive vasculopathy, and 26 cases had nephrosclerosis or glomerulosclerosis. Common extrarenal secondary causes of hypertension were excluded by necropsy examination. The pathogenesis is suggested to involve primary hypertension leading to renal and cardiac disease. Elevated sympathetic activity might be an underlying factor in the frequent development of primary systemic hypertension in the pygmy marmoset, as for the owl monkey.

Complete genome analysis confirms that the pygmy marmoset adenovirus is a variant of the skunk adenovirus 1 – Short communication

The complete genomic sequence along with phylogenetic analyses of an adenovirus (AdV), isolated from a dead captive pygmy marmoset (Callithrix pygmaea) from a Hungarian zoo is reported. Earlier, based on the phylogenetic analysis of the sequence of a PCR-amplified fragment from the DNA polymerase gene, the pygmy marmoset AdV (PMAdV) has been reported to cluster closest to certain chiropteran AdVs. In the following years similar AdVs were discovered in additional mammalian hosts, including a skunk (Mephitis mephitis), African pygmy hedgehogs (Atelerix albiventris), North American porcupines (Erethizon dorsatum) and grey fox (Urocyon cinereoargenteus). After the full genome analysis of the skunk adenovirus (SkAdV-1), a novel species Skunk mastadenovirus A (SkAdV-A) has been established. The AdVs, originating from the African pygmy hedgehogs, have been found to belong to virus species SkAdV-A. Partial gene sequences from the porcupine AdVs have also implied their very close genetic relatedness to SkAdV-A. The complete genomic sequence of PMAdV, examined in this study, was found to share 99.83% nucleotide identity with SkAdV-1, thus unequivocally represents a genomic variant of SkAdV-1. The observation that viruses classifiable as SkAdV-A are able to infect and cause diseases in several, distantly related mammals seems to deserve further studies to elucidate the infection biology of this intriguing AdV.

Translocation and radio-telemetry monitoring of pygmy marmoset, Cebuella pygmaea (Spix, 1823), in the Brazilian Amazon

Two groups of pygmy marmoset (Cebuella pygmaea) were rescued along the left bank of the Madeira River during the formation of Santo Antônio Hydroelectric Dam reservoir in the state of Rondônia, Northern Brazil. Reintroduction of both groups occurred in areas of open Tropical rainforest located within the project´s Permanent Preservation Area. A post-release monitoring was conducted for three months using radio-telemetry. Individuals of each group remained together and settled in stable home ranges near their respective release sites. The mortality rate of translocated animals was about 7%. This seems to be the first report documenting the complete group translocation of C. pygmaea and the first to successfully employ radio-telemetry techniques in monitoring this species. This study demonstrated the feasibility of translocation and the use of radio-telemetry in monitoring C. pygmaea.

Ventilatory and metabolic responses to hypoxia in the smallest simian primate, the pygmy marmoset

The pygmy marmoset ( Cebuella pygmaea) is the smallest New World Monkey (average body mass of 120–130 g). As such, it faces possible challenges to thermoregulation. Small mammals (e.g., rats) are well known to lower body temperature and metabolism in response to hypoxia; however, small primates have not been studied in this respect nor have, in general, the interactions between metabolism and ventilation. Because little is known about these responses in small primates, it seemed of great interest to assess the hypoxia-induced metabolic depression and drop in body temperature and the associated ventilatory requirements in this species under hypoxic conditions. Exposure to graded hypoxia (30 min at each of 18, 16, 14, 12, and 10% O2) caused body temperature to drop from the normoxic value of 39 to 37°C. This was accompanied by a marked metabolic depression (O2 consumption was ∼68% of the normoxic value, implying a suppression of metabolism greater than that predicted from a typical value of the effect of 10°C change on metabolism of 2–3 times). Minute ventilation declined in parallel to metabolism, maintaining a constant air-convection requirement during hypoxia; thus this species did not show the typical mammalian hyperventilation. Acute exposure to 10% O2 led to a similar overall decline in metabolism and body temperature and qualitative differences in the timing of these changes. The pygmy marmoset shares some similarities in its hypoxic metabolic response with other mammals of similar size yet appears to be unique in its much diminished ventilatory response to hypoxia.

'BABBLING' IN PYGMY MARMOSETS: DEVELOPMENT AFTER INFANCY

Infant pygmy marmosets (Cebuella pygmaea) are extremely vocal with much of their calling occurring in long sequences of mixed call-types that appears to have several parallels to the babbling of human infants (Elowson et al., 1998b). We refer to this vocal behaviour as Pygmy Marmoset Babbling (PMB) (Elowson et al., 1998a). We followed several of our original subjects beyond infancy to adulthood. Babbling bouts continued to appear through the age of puberty though at a reduced rate from that seen in infancy, but babbling was rarely observed in adults. With increasing age the vocal bouts contained a greater diversity of call types per bout and a decrease in call series duration. In addition, with increasing age there were decreasing proportions of calls that were Adult Variant and Infant calls and an increase in Adult calls. Structural analyses of trills, the most common call type found in vocal bouts, showed increased proportions of well-formed trills and decreased proportions of poorly formed trills with increased age, with different features reaching adult form at different ages. Babbling by juvenile marmosets was associated with increased social interactions with other group members as we had observed with infants. 'Babbling' in both infant and juvenile marmosets might provide vocal practice as well as attract attention from other group members.