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The establishment of a sylvatic reservoir of Zika virus (ZIKV) in the Americas is dependent on the susceptibility of primates of sufficient population density, the duration and magnitude of viremia, and their exposure to the human mosquito-borne transmission cycle. To assess the susceptibility of squirrel ( Saimiri sp.) and owl monkeys ( Aotus sp.) to infection, we inoculated four animals of each species with ZIKV from the current epidemic. Viremia in the absence of detectible disease was observed in both species and seroconversion occurred by day 28. ZIKV was detected in the spleen of three owl monkeys: one at 7 days postinoculation (dpi) and two at 14 dpi. This study confirms the susceptibility to ZIKV infection of two Neotropical primate species that live in close proximity to humans in South America, suggesting that they could support a widespread sylvatic ZIKV cycle there. Collectively, establishment of a ZIKV sylvatic transmission cycle in South America would imperil eradication efforts and could provide a mechanism for continued exposure of humans to ZIKV infection and disease.

Owl monkeys are New World primates frequently used in biomedical research. Despite the historical difficulty of breeding owl monkeys in captivity, several productive owl monkey breeding colonies exist currently. The animals in the colony we describe here are not timed-pregnant, and determination of gestational age is an important factor in prenatal care. Gestational age of human fetuses is often determined by using transabdominal measurements of fetal biparietal diameter. The purpose of this study was to correlate biparietal diameter measurements with gestational age in owl monkeys. We found that biparietal diameter can be used to accurately predict gestational age in owl monkeys.

Background: Cardiovascular disease, especially cardiomyopathy, was the major cause of death among owl monkeys (Aotus sp.) at a major colony and threatened colony sustainability. For this study, echocardiography (echo) and electrocardiography (ECG) normal values were established, and cardiomyopathy animals identified., Methods: Forty-eight owl monkeys were studied, 30 older than 10 years of age ('aged') and 8 of age 5 years ('young'). Eight aged owl monkeys had cardiomyopathy., Results and Conclusions: Aged Aotus had increased left ventricular posterior wall thickness over young animals. Left ventricular diameter and ejection fraction appeared to be the best identifying measurements for cardiomyopathy. There were no differences in the ECG.

This report describes congenital radial and thumb aplasia in a neonatal owl monkey. Congenital limb deformities in human neonates and Old World primate species have been well characterized. The many probable causes of these congenital defects in skeletal structure include fetal exposure to environmental toxins and genetic influences. In nonhuman primates, the cause frequently remains undetermined. In the case we present, the neonate presented for examination because of inability to cling to the dam. The forelimbs were contracted distally, and thumbs were absent. Radiographs indicated complete radial aplasia and other skeletal abnormalities. This description is the fi rst case study of congenital radial and thumb aplasia in a New World primate species.

Lesions consistent with heart failure were found in 23 of 88 adult squirrel monkeys that died between 1995 and 1999 at the Squirrel Monkey Breeding and Research Resource (SMBRR). This provided a rationale for a study surveying aged animals in the SMBRR for normal cardiac characteristics, using echocardiography (ECHO) and electro-cardiogram. In the pilot study, ECHO and electrocardiography were performed on 59 healthy female squirrel monkeys aged 10 years or older and 39 five-year-old monkeys. Parameters were heart rate, P-wave duration and amplitude, and PR, QRS, and QT intervals (electrocardiography), and ejection fraction. Two animals with cardiomyopathy were identified and received similar testing. Advanced-study animals had the same measurements, plus left ventricular internal diameter-systole (LVIDs) and -diastole (LVIDd), left atrial diameter-diastole (LADd) and aortic root diameter-diastole (AoRDd) by use of ECHO. Significant differences were found between groups in LADd, and P-wave and QRS interval durations. In a clinical context, these differences were not considered to be substantial. Normal aged female squirrel monkeys had significant increases in heart dimension and longer P- and QRS-wave durations than did monkeys of a five-year-old control group, although the increases were not considered clinically relevant. This study documents myocardial dynamics in healthy saimiri and those with cardiomyopathy.

Dental calculus and associated periodontal disease are serious clinical problems in captive squirrel monkeys. Calculus begins to appear as early as 2 years of age, with subsequent development of periodontal disease, dental abscessation, tooth loss and other sequelae. When used as a feed additive, sodium hexametaphosphate (HMP) retards the growth of calculus on previously cleaned teeth in rhesus monkeys, lemurs, and other species. We wanted to determine whether HMP would reduce dental calculus in squirrel monkeys (Saimiri spp.) whose teeth had not been pre-cleaned. The study animals were divided into two groups. One received a standard diet; the other received an identical diet containing the HMP additive at a concentration effective in other primate and non-primate species that had received dental cleaning prior to treatment with HMP. Teeth were graded for extent of calculus formation at the start of the study and at 3 and 6 months during HMP treatment. We compared the results from the two groups both by total score per animal and according to tooth type (e.g., incisors versus incisors in test and control groups). At the end of 6 months, dental calculus did not differ significantly between the experimental groups. Therefore, we conclude that HMP is ineffective in squirrel monkeys with preexisting dental calculus.

This study evaluated manual caliper measurement of fetal BPD in Saimiri through the abdomen of the dam (TBPD) for correlation with paired ultrasound measurements, prediction of delivery date, subspecies variation, prediction of pregnancy outcome, and correlation between postpartum BPD and TBPD. Regression analysis revealed a close relationship between TBPD measurements and those obtained by ultrasound (P < 0.001). TBPD for Saimiri boliviensis boliviensis increased from a mean of 14.8 +/- 0.3 mm for 11 weeks prepartum to a delivery week measurement of 33.2 +/- 0.2mm. Delivery-week TBPD of Saimiri boliviensis peruviensis were significantly smaller than Saimiri sciureus sciureus (P < .05). Delivery week TBPD had a correlation coefficient of 0.64 with paired post-patrum measurements. No complications were associated with the technique. Delivery date could be predicted within two weeks. TBPD is an inexpensive, safe, rapid method of approximating fetal growth during the last half of pregnancy in Saimiri.

Purpose: To explore the possibility that inoculation of the eyes of African green monkeys with simian varicella virus (SVV) induces the symptoms of herpes zoster ophthalmicus (HZO), as seen in humans, and to develop a realistic and reproducible animal model of herpes zoster ophthalmicus for experimental studies., Methods: In the first experiment, the right eyes of three African green monkeys were inoculated by intrastromal and subconjunctival injections with a suspension of SVV-infected Vero cells. In the second experiment, three additional monkeys were pretreated with intramuscular injections of methylprednisolone (41 mg/kg) for 7 days before ocular inoculation with SVV and for 3 weeks at 14 mg/kg after virus inoculation. The eyes were examined by slit-lamp biomicroscopy. Histologic, immunohistochemical, and electron microscopic studies were performed., Results: In the first experiment, all three animals developed high titers of anti-SVV antibodies (IgG). Diffuse stromal opacity, with keratitic precipitates, stromal edema, and mild vascularization of the cornea, appeared 12 to 14 days after inoculation. The onset of ocular disease was correlated with the rise in serum antibody levels. There was no clinical evidence of a systemic viral infection resulting from the corneal inoculations in these monkeys. In the second experiment, all three animals treated with methylprednisolone developed severe ocular pathology within 1 week of inoculation. The clinical appearance of the diseased eyes strongly indicated that local viral infection had occurred. Dendritiform keratitis, corneal erosion, and stromal necrosis with vascularization of the cornea was seen in all the eyes. The disease resolved within 4 to 5 weeks of inoculation, leaving opaque, vascularized corneas. Histologic studies showed that inflammatory cells and viral antigens were widespread throughout the diseased corneas. A high titer of anti-SVV antibody (IgG) was detected in the immunosuppressed monkeys, but no evidence of systemic viral infection was observed., Conclusions: The authors propose that inoculation of the eyes of methylprednisolone-treated African green monkeys with simian varicella virus provides an appropriate animal model for studies of the virology and immunopathology of ocular varicella virus infection.

The immunological and biological activities of growth hormone (GH) and prolactin (PRL) in the pituitary gland and serum of the squirrel monkey (Saimiri boliviensis boliviensis) have been studied. Proteins in pituitary homogenates were solubilized in 1% SDS, electrophoresed on 12% polyacrylamide gels, and transferred to nitrocellulose. Squirrel monkey GH and PRL were identified by immunoblotting with anti-human GH antibodies and a monoclonal antibody to ovine PRL, 6F11, respectively. Squirrel monkey GH appeared predominantly as two proteins of apparent molecular weight 22 and 20 kD, corresponding to native and variant forms of human GH. Squirrel monkey PRL appeared as two proteins of apparent molecular weight 24 and 26.5 kD, which co-migrated with native and glycosylated forms of ovine PRL. The cross-reactivity of neutralizing antibodies to human GH and PRL with squirrel monkey GH and PRL were examined using the Nb2 lymphoma bioassay. One of three monoclonal antibodies to human GH (2A1) neutralized squirrel monkey GH with an apparent affinity for squirrel monkey GH (IC 50 = 70 ng IgG/ml) which was fourfold lower than for human GH (IC 50 = 15 ng IgG/ml). Both polyclonal [AR38-5(1)] and monoclonal (9C3) antibodies to human PRL inhibited the activity of squirrel monkey PRL, athough their affinities for squirrel monkey PRL were four- and twentyfold lower than for human PRL. The activities of antibodies 2A1 and 9C3 on GH and PRL in squirrel monkey serum were also examined by the Nb2 bioassay. The anti-glucocorticoid RU486 was used in all incubations with squirrel monkey serum to eliminate the effect of high glucocorticoid levels on Nb2 cell growth. The mitogenic activity of squirrel monkey serum in the Nb2 assay was completely eliminated in the presence of 2A1 and 9C3. This study represents the first description of the biochemistry of GH and PRL in the squirrel monkey., (Copyright © 1992 Wiley‐Liss, Inc., A Wiley Company.)

Interest in refining noninvasive methods of diagnosis and further characterization of squirrel monkeys (Saimiri sp.) as a model for pediatric cardiology studies led to this investigation of electrocardiogram (ECG) changes associated with changes in age and position. During a single delivery season, ECGs were performed at 1 day, 1 month, and 1 year of age. For each age group, ECGs were recorded with animals in dorsal, ventral, and right lateral recumbency. The 1-day-old group had the lowest heart rates (271 +/- 10, right lateral recumbency, mean +/- SEM) relative to the other age groups. One-year-old monkeys had heart rates of 333 +/- 18. One-month-old infants had rates significantly higher than the other two age groups (366 +/- 4). The QRS frontal-plane axis showed an age-related leftward change from 1 day (151 +/- 28 degrees) to 1 year of age (121 +/- 44 degrees) while the P-wave frontal plane axis remained nearly constant over a narrow range at all ages. The pattern of heart rate changes with age were similar to those in humans, although the ranges of absolute heart rates were markedly different. These data suggest that factors that influence maturational changes in heart rate, conduction time (as reflected by ECG intervals) and cardiac chamber size and position (inferred from axis and voltage) are similar among primates of widely variant body sizes.

Neonatal deaths are a serious problem in breeding colonies of squirrel monkeys. Seriously ill neonates in our colony are always hypoglycemic on presentation. To determine normal glucose values for squirrel monkey infants of various ages, serum glucose determinations were done at 1, 3, 7, 10, 14 days and 1 month of age using a standard laboratory test for serum glucose. Glucose concentration increased from a low of 49 +/- 3 mg/dl (Mean +/- SEM) at 1 day (n = 21) to 109 +/- 4 mg/dl at 1 month of age (n = 17). Glucose values for 1, 3 and 7 day-old infants were significantly lower than 1 month-old infants (P less than .05). To provide a time-averaged indication of blood glucose, glycosylated hemoglobin (GHb) measurements were made at 1 day, 1 week, 2 weeks, 1 month, 2 months, 1 year of age and in adults (greater than 3 years of age). GHb values ranged from 2.6% +/- 0.1 for 1 day old infants (n = 13) to 4.0 +/- 0.2 for adults (n = 10) with a steady increase during the first 2 months of life. Animals 1 year of age and younger had significantly lower glycosylated hemoglobin than adults. These studies indicate that blood glucose concentration is significantly lower in squirrel monkey neonates than in older infants, juveniles and adults. Maternal rejection, trauma, and associated problems occur commonly in socially reared squirrel monkeys. The marginal hypoglycemic state of these infants places them at high risk for clinical hypoglycemia as a sequel to such perturbations.

Ketamine hydrochloride's effect on glucose clearance-insulin secretion during intravenous glucose tolerance testing was studied in five African green monkeys. Animals were tested with ketamine anesthesia and then had indwelling cannulas implanted and were retested both in the presence and absence of ketamine anesthesia. Serum glucose and insulin concentrations were determined. There were no significant differences in the glucose clearance rate (K value), basal glucose and insulin concentrations, maximum insulin concentration, and area under the insulin response curve, among the three different conditions.

The squirrel monkey (Saimiri sciureus) has been proposed as a model for urogenital trichomoniasis in man, but has not been accepted as such because of the purported presence of naturally occurring vaginal trichomonads in this animal. The study published here shows that these are easily eradicated organisms of intestinal origin, which eliminates the potential confusion created by them. In addition, our experiments have shown that the hormonal status of primates seems to be a determinant in successfully establishing experimental trichomoniasis. This experimental infection recapitulates the clinical observations sufficiently to warrant the use of this model for studies of vaginal trichomoniasis.

Reproductive development in male African green monkeys was characterized by evaluating both luteinizing hormone (LH) and testosterone (T) before and after gonadotrophin releasing hormone (GnRH) stimulation in relation to the physical maturation of the testis. There were LH responses to GnRH at all ages studied, but the failure of some animals to respond at earlier ages suggested developmental changes in the responsiveness of the pituitary. The T secretion developed progressively but did not reach adultlike characteristics until approximately 44 months of age, at which time sperm could be demonstrated in ejaculated semen.

Periapical abscesses of canine teeth in a group of 47 male cynomolgus macaques are found to be associated with a procedure, involving cutting the canine teeth, used to make non-human primates less hazardous. Examination of 150 canine teeth in dry specimens revealed 30 cut teeth with no exposure of the pulpal chamber and 107 cut teeth where the dental pulp had been exposed. Of those teeth which had the pulpal chamber exposed by the cutting procedure, 85 (79.4%) showed clear evidence of osseous changes consistent with abscess formation in the apical regions.

The Whittier Narrows earthquake sequence (local magnitude, M(L) = 5.9), which caused over $358-million damage, indicates that assessments of earthquake hazards in the Los Angeles metropolitan area may be underestimated. The sequence ruptured a previously unidentified thrust fault that may be part of a large system of thrust faults that extends across the entire east-west length of the northern margin of the Los Angeles basin. Peak horizontal accelerations from the main shock, which were measured at ground level and in structures, were as high as 0.6g (where g is the acceleration of gravity at sea level) within 50 kilometers of the epicenter. The distribution of the modified Mercalli intensity VII reflects a broad north-south elongated zone of damage that is approximately centered on the main shock epicenter.

In a large breeding colony of squirrel monkeys, a previous study demonstrated apparent universal infestation of adult animals with enteric trichomonads. The potential of these organisms to act as a source of experimental variability and the potential pathogenic effects of parasitism in this species stimulated this study of organism acquisition and treatment. Age of natural infestation with trichomonads was determined from results of microscopic examination and culture of fecal samples from infants of different ages. A majority of squirrel monkey infants showed first evidence of trichomoniasis at 2 to 4 weeks of age, with apparent 100% infestation by 8 weeks of age. Treatment of adult monkeys was investigated. In vitro techniques were utilized to determine sensitivity to metronidazole of a number of isolates. An effective regimen for treatment of adult monkeys was determined to be 25 mg/kg body weight of metronidazole given orally, twice daily for 5 days., (Copyright © 1988 Wiley-Liss, Inc., A Wiley Company.)

A knotted umbilical cord was found in a third trimester Cercopithecus aethiops abortus. On the maternal side of the knot, the umbilical cord was engorged with blood. The umbilical cord on the fetal side of the knot was devoid of blood, suggesting that the knot may have occluded blood flow to the fetus.