Spontaneous heart disease in the adult chimpanzee (Pan troglodytes)

Background  A high incidence of heart disease, especially idiopathic cardiomyopathy (IC), is seen in chimpanzees ( Pan troglodytes ).
Methods  We reviewed clinical records and necropsy reports of 87 adult chimpanzees for possible causes of heart disease/IC. We examined age, sex, cause of death, weight, diet, environment, infectious diseases, experimental uses and clinical pathology.
Results  The overall prevalence of heart disease in chimpanzees was 67.81%; the prevalence of IC was 51.72%. The prevalence of IC was significantly higher in males (60.32%) than that in females (29.17%, P  = 0.009). The prevalence of other heart disease was higher in females (25%) than that in males (12.70%, P  = 0.165). Heart failure occurred in 47.13% of chimpanzees. Heart disease was the primary cause of death in 34.49% of chimpanzees; 29.88% died of unknown causes.
Conclusions  We found no evidence that diet, environment, viral agents, experimental use or disease exposure contributed to the deaths resulting from IC in chimpanzees.     

Expression of beta-defensin-1 in chimpanzee (Pan troglodytes) airways

In human airways, beta-defensins function in the elimination of various pathogens. They have been identified in a wide range of species. Here we report the identification and expression of chimpanzee beta-defensin-1 (cBD1), which is a homolog of human beta-defensin-1, in chimpanzee airways and skin. The cBD1 cDNA sequence differs by only one synonymous nucleotide substitution compared to the human cDNA sequence. In situ hybridization revealed that in lung tissue beside alveolar macrophages also airway epithelial cells, endothelial cells and type II pneumocytes express cBD1 mRNA. In skin, cBD1 mRNA was expressed in keratinocytes and endothelial cells. Together, these results show similarity in structure and expression pattern and perhaps in function.     

Foreign body urethral obstruction in a chimpanzee (Pan troglodytes)

Background  A 34-year-old, captive-born, vasectomized male chimpanzee ( Pan troglodytes ) presented with lethargy and scrotal swelling.
Methods  Urethral obstruction was diagnosed via urethroscopy.
Results  Removal of the grass stem foreign body resolved the obstruction. Scrotal and preputial ulceration developed from urine scald, which was managed with surgical debridement and antibiotics.
Conclusions  After 7 weeks, the animal was reintroduced to its troup and has been healthy for 11 months.     

Semen characteristics of the adult male chimpanzee (Pan troglodytes)

The chimpanzee, because of its similarities to the human, is especially valuable in studies of reproductive function. However, relatively little is known about the physiology of reproduction in the adult male chimpanzee. This study provides, for five adult male chimpanzees, baseline values for testicular volume without and with pressure and for cellular and biochemical characteristics of ejaculates collected by artificial vagina (AV). There was no correlation between body weight and testicular volume measured without or with pressure. The ratios of mean testicular volume without and with pressure were not statistically different among animals. Statistical analysis of penetration of denuded hamster oocytes by ejaculated chimpanzee sperm revealed no correlations between sperm count and percentage of eggs penetrated. There was significant variability in concentrations of protein and fructose and in activities of alpha-glucosidase and acid phosphatase among samples from different animals. Computer-assisted motion analysis (CAMA) of sperm provided baseline data on motion parameters necessary for future evaluation of this technique for semen analysis in the chimpanzee. The level of demonstrated inter-animal variation mandates use of each animal as its own control for studies on normal and altered reproductive function. © 1993 Wiley-Liss, Inc.     

Nevus lipomatosus cutaneus superficialis (Hoffmann-Zurhelle) in a chimpanzee (Pan troglodytes)

BACKGROUND: A 32-year-old, male chimpanzee (Pan troglodytes) kept in a zoo developed a focally extensive, proliferative, cerebriform, dermal mass at the left inner thigh extending to the inguinal region. After surgical removal, the mass recurred and extended progressively over a period of 5 years. METHODS AND RESULTS: At necropsy, a 20 x 20 cm large, well defined, papular and partly verrucous, rubbery mass composed of multiple large, soft nodules measuring up to 4 cm in diameter was observed in the left thigh and inguinal region. Histological examination revealed a multifocal expansion of the dermis by mature adipocytes that were arranged in small islands to large lobular aggregates. Dermal proliferations of adipocytes were almost completely separated from the subcutaneous adipose tissue. CONCLUSIONS: This is the first report of a unique lesion that resembles human Nevus lipomatosus cutaneus superficialis in a chimpanzee and is different from lipoma or liposarcoma.     

Neoplasia in the chimpanzee (Pan spp.)

Background  Chimpanzees have over 98% genomic sequence homology with humans and may have a similar host response to malignancy. There is minimal information concerning cancer in the chimpanzee and such information would be valuable to individuals caring for and using them for research.
Methods  Spontaneous neoplasia that was documented in two chimpanzee colonies and in the literature were evaluated statistically.
Results  In all, 105 spontaneous and 12 experimental neoplasms were diagnosed. Seventy-four spontaneous tumors occurred in females, 24 in males, and seven in animals of undetermined sex. Of the spontaneous tumors 89 were benign, 14 were malignant, and two were undetermined. Neoplasia was most common in the urogenital system in females.
Conclusions  Neoplasia is not uncommon in the chimpanzee, is generally benign, and occurs primarily in the urogenital system in females.     

Flexibility and persistence of chimpanzee (Pan troglodytes) foraging behavior in a captive environment

As a result of environmental variability, animals may be confronted with uncertainty surrounding the presence of, or accessibility to, food resources at a given location or time. While individuals can rely on personal experience to manage this variability, the behavior of members of an individual's social group can also provide information regarding the availability or location of a food resource. The purpose of the present study was to measure how captive chimpanzees individually and collectively adjust their foraging strategies at an artificial termite mound, as the availability of resources provided by the mound varied over a number of weeks. As predicted, fishing activity at the mound was related to resource availability. However, chimpanzees continued to fish at unbaited locations on the days and weeks after a location had last contained food. Consistent with previous studies, our findings show that chimpanzees do not completely abandon previously learned habits despite learning individually and/or socially that the habit is no longer effective.     

Placental implications for pregnancy complications in the chimpanzee (Pan troglodytes)

Placentas from 28 term chimpanzee pregnancies, including two sets of dichorionic-diamniotic twin-pregnancies, were examined and compared histopathologically with those obtained from 171 small-for-dates (SFD), 306 premature, and 77 pregnancy toxemic human infants. Term infant and placental weights for the chimpanzee were generally smaller than for any of the human categories studied. Macroscopically, the chimpanzee placentas showed a high frequency of extrachorialis, infarctions, intervillous thrombi, and marginal hemorrhages, pathologies frequently associated with pregnancy toxemia and abruptio placenta in the human being. Yet, ultrastructurally, the chimpanzee chorionic villi evidenced well-developed organella, syncytial microvilli, and chorionic capillaries, although villitis and inflammation of the membranes and cord were not infrequently seen. These findings suggest that chimpanzees may suffer the same obstetric complications seen in human pregnancies.     

Longitudinal analysis of length growth in the chimpanzee (Pan troglodytes)

The adolescent growth spurt in linear dimension in humans is considered to be unique among mammals, but few comparative studies have been done, even on chimpanzees. Growth of the summed length of crown to rump, thigh, and leg was studied longitudinally in 12 chimpanzees. We took body weight growth and reproductive maturation into consideration. Reproductive maturation was monitored by the swelling of sexual skin and menarche in females, and by testicular development in males. We applied two relationships found in humans between body length growth and the environment to the chimpanzees. The first relationship was the robustness of the growth spurt, meaning that the spurt is absent only in individuals under the most severe environmental pressure. Subjects maturing in a favorable or even mediocre environment are anticipated to show the growth spurt. The second relationship was catch-up growth, where, when the environment is ameliorated, growth may be accelerated to attain the target size. Catch-up growth at the end of the juvenile period may mimic the adolescent growth spurt. Results showed that subjects living under favorable conditions did not exhibit a growth spurt, and that it was only the subjects who had delayed growth in the juvenile period that showed a spurt in adolescence, the period when reproductive maturation occurred. Although we have concluded that chimpanzees do not have an adolescent growth spurt, except in cases of catch-up growth, this does not mean that they have a different growth pattern from that of humans. The absence of a growth spurt may be associated with adaptations to chimpanzee patrilineal society, where adolescent males are incorporated into the adult hierarchy at a low rank.     

Pneumatic processes in the temporal bone of chimpanzee (Pan troglodytes) and gorilla (Gorilla gorilla)

The ontogeny of human temporal bone pneumatization has been well studied from both comparative and clinical perspectives. While a difference in the extent of air cell distribution has been noted in our closest living relatives, chimpanzees and gorillas, the processes responsible have been relatively unexplored. To examine these processes, a large, age‐graded series of hominoid skulls was radiographed and the progress of pneumatization recorded. Additionally, a subsample of 30 chimpanzees and 12 gorillas was subjected to high‐resolution CT scanning. Neonatal specimens show a well‐developed mastoid antrum, as well as a capacious hypotympanum extending into the petrous apex. In African apes, as in humans, the mastoid antrum serves as the focus for air cell expansion into the mastoid and immediately adjacent areas. In chimpanzees and gorillas, however, a pronounced lateral structure, described as the squamous antrum, serves as the focus of pneumatization for anterior structures such as the squamous and zygomatic. The diminution of this structure in Homo sapiens explains the difference in air cell distribution in these regions. J. Morphol. 241:127–137, 1999. © 1999 Wiley‐Liss, Inc.     

Deciduous dentition eruption sequence of the laboratory-reared chimpanzee (Pan troglodytes)

Eruption sequence and age ranges for the maxillary and mandibular deciduous dentition were generated from serial dental study models from 28 laboratory-reared chimpanzees (Pan troglodytes). These data can serve as additional normative, baseline information for the evaluation of fetal insults on neonatal growth and development in the laboratory-reared chimpanzee.     

Bipedality in chimpanzee (Pan troglodytes) and bonobo (Pan paniscus): testing hypotheses on the evolution of bipedalism

A host of ecological, anatomical, and physiological selective pressures are hypothesized to have played a role in the evolution of hominid bipedalism. A referential model, based on the chimpanzee (Pan troglodytes) and bonobo (Pan paniscus), was used to test through experimental manipulation four hypotheses on the evolution of hominid bipedalism. The introduction of food piles (Carry hypothesis) increased locomotor bipedality in both species. Neither the introduction of branches (Display hypothesis) nor the construction of visual barriers (Vigilance hypothesis) altered bipedality in either species. Introduction of raised foraging structures (Forage hypothesis) increased postural bipedality in chimpanzees. These experimental manipulations provided support for carrying of portable objects and foraging on elevated food-items as plausible mechanisms that shaped bipedalism in hominids.     

An unusual incident of adoption in a wild chimpanzee (Pan troglodytes) population at Gombe National Park

Allomothering and adoption are well documented across primate species. Multiple hypotheses have been proposed to explain the evolution of such behavior according to the costs and benefits to the caregiver, mother, and infant. Permanent adoptions and allomothering have been observed in chimpanzees, but they typically involve the infants' siblings or nulliparous females. Here, I report a unique incident of adoption where an infant was adopted by its grandmother without the death of its mother. I conclude by considering how the adoption may have benefited the grandmother, mother, and infant.     

Locking plate femur fracture repair in a juvenile Western chimpanzee (Pan troglodytes verus) in Sierra Leone

This case reports the successful management of a traumatic diaphyseal femoral fracture in an infant Western chimpanzee (Pan troglodytes verus) from a rescue centre in Sierra Leone using a 2.4-mm intramedullary pin and two 2.7-mm String of Pearls^™ locking plates. Locking plate use has not been previously described in chimpanzees.     

Ecological context of savanna chimpanzee (Pan troglodytes verus) termite fishing at Fongoli, Senegal

Chimpanzees (Pan troglodytes verus) at Fongoli, Senegal, consume termites year-round. Understanding the ecological context behind this behavior is especially important in light of the environmental conditions at Fongoli. This mosaic savanna habitat is one of the hottest and driest sites where chimpanzees have been studied. Two genera and four species of termites were found in association with tools used by chimpanzees in a sample of 124 termite mounds that were monitored. The chimpanzees of Fongoli termite fish predominantly in woodland and forest habitat types, and, although woodland accounts for the majority of the chimpanzees' home range, forest habitat types comprise only about 4% of their range. Thus, habitat type has an influence on the Fongoli chimpanzees' termite fishing. Termite consumption to the degree seen at Fongoli may have particular significance for hominid evolution, given the expansion of Pliocene hominids into increasingly open, hot, and dry habitats.     

Leucoencephalopathy with cerebral calcinosis in a young chimpanzee (Pan troglodytes) - a case report

CASE HISTORY: A 4-year-old chimpanzee (Pan troglodytes) had a clinical history of a 2-year progressive central nervous dysfunction including convulsions and severe paralysis. RESULTS: Gross pathology revealed cerebral atrophy, ventricular enlargement and a severe encephalomalacia with extensive calcifications. Histologically, the white matter showed diffuse demyelination as well as vascular and perivascular calcifications which also involved the basal ganglia. Blood vessels with less distinctive calcium deposits exhibited periodic acid Schiff positive hyalinosis. Large areas of necrosis, hemorrhage and intense gliosis were also present. Activation of astrocytes and macrophages was confirmed by immunohistochemical methods. CONCLUSIONS: The etiology of the leucoencepalopathy could not be ascertained by macroscopic, histological and immunohistochemical examinations. Potential differential diagnoses include the rarely occurring Fahr's disease in humans, arteriosclerosis, storage disease and the Aicardi-Goutières syndrome. Based on the results of the postmortal examinations Fahr's disease is regarded as the most likely diagnosis in the present case of the chimpanzee.