Comparison of fine-needle aspiration techniques.

BACKGROUND: Fine-needle aspiration (FNA) has been reported since 1912 beginning with the use of trocars and other specialized instruments that were impractical. Since then, FNA has proven to be a successful alternative technique to excisional biopsy for some assays despite a few limitations. METHODS: In this study, we compared four different techniques for FNA in rhesus macaques by evaluating total live cells recovered and cell viability using a standard 6 mL syringe and 1.5-inch 22-gauge needle. RESULTS: Technique B which was the only technique in which the needle was removed from the syringe after collection of the sample to allow forced air through the needle to expel the contents into media followed by flushing of the syringe and needle resulted in the highest total cell count and second highest cell viability in recovered cells. CONCLUSION: Based on our results, Technique B appears to be the superior method.

High incidence of rhesus enteric calicivirus infections and diarrhea in captive juvenile macaques: a likely association.

BACKGROUND: The rhesus enteric caliciviruses (ReCVs) were recently described. METHODS: Prevalence of ReCV antibodies was tested in six species of captive non-human primates. RESULTS: High ReCV seroprevalence was revealed in rhesus and cynomolgus macaques. CONCLUSIONS: High rates of ReCV seroprevalence and diarrhea in juvenile macaques suggest that ReCVs may play a role in morbidity.

Reproductive efficiency of captive Chinese- and Indian-origin rhesus macaque (Macaca mulatta) females.

Reproductive and survival records (n=2,913) from 313 Chinese-origin and 365 Indian-derived rhesus macaques at the Tulane National Primate Research Center (TNPRC) spanning three generations were studied. Least-squares analysis of variance procedures were used to compare reproductive and infant survival traits while proportional hazards regression procedures were used to study female age at death, number of infants born per female, and time from last birth to death. Chinese females were older at first parturition than Indian females because they were older when placed with males, but the two subspecies had similar first postpartum birth interval (1st PPBI) and lifetime postpartum birth interval (LPPBI). Females that gave birth to stillborn infants had shorter first postpartum birth intervals (1st PPBI) than females giving birth to live infants. Postpartum birth intervals decreased in females from age 3 to 12 but then increased again with advancing age. Chinese infants had a greater survival rate than Indian infants at 30 days, 6 months, and 1 year of age. Five hundred and forty-three females (80.01%) had uncensored, or true records for age at death, number of infants born per female, and time from the birth until death whereas 135 females (19.91%) had censored records for these traits. Low- and high-uncensored observations for age at death were 3 and 26 years for Chinese, and 3 and 23 years for Indian females. Uncensored number of infants born per female ranged from 1 to 15 for Chinese females and 1 to 18 for Indian females. Each of these traits was significantly influenced by the origin×generation interaction in the proportional hazards regression analyses, indicating that probabilities associated with age at death, number of infants born per female, and time from last birth to death for Chinese and Indian females did not rank the same across generations.

Estimates of heritability for reproductive traits in captive rhesus macaque females.

Records from a colony of captive Indian rhesus macaques (Macaca mulatta) were used to estimate heritability for a number of reproductive traits. Records were based on a total of 7,816 births by 1,901 females from 1979 to 2007. Heritability was estimated with a linear animal model using a multiple trait derivative free REML set of programs. Because no male parents were identified, the numerator relationship matrix contained female kinships established over six generations. Reproductive traits included female age at the birth of the first, second and last infant, age at death, inter-birth intervals, number of infants born per female and infant survival. Heritability for each trait was estimated as the ratio of the additive genetic variance to phenotypic variance adjusted for significant fixed effects. Estimates of heritability for early reproduction ranged from 0.000+/-0.072 for birth interval after the first reproduction to 0.171+/-0.062 for age of female at the first infant. Higher estimates of heritability were found for female longevity [0.325+/-0.143] and for productivity of deceased females born before 1991 [0.221+/-0.138]. Heritability for infant survival ranged from 0.061+/-0.018 for survival from 30 days to 1 year to 0.290+/-0.050 for survival from birth to 30 days when adjusted to an underlying normal distribution. Eight of the 13 estimates of heritability for reproductive traits in this study were different from zero [P<0.05]. Generally, heritability estimates reported in this study for reproductive traits of captive rhesus macaque females are similar to those reported in the literature for free-ranging rhesus macaque females and for similar reproductive traits of other species. These estimates of heritability for reproductive traits appear to be among the first for a relatively large colony of captive rhesus macaque females.

Clinical and Immunological Metrics During Pediatric Rhesus Macaque Development.

Background: Clinical measurements commonly used to evaluate overall health of laboratory animals including complete blood count, serum chemistry, weight, and immunophenotyping, differ with respect to age, development, and environment. This report provides comprehensive clinical and immunological reference ranges for pediatric rhesus macaques over the first year of life. Methods: We collected and analyzed blood samples from 151 healthy rhesus macaques, aged 0-55 weeks, and compared mother-reared infants to two categories of nursery-reared infants; those on an active research protocol and those under derivation for the expanded specific-pathogen-free breeding colony. Hematology was performed on EDTA-anticoagulated blood using a Sysmex XT2000i, and serum clinical chemistry was performed using the Beckman AU480 chemistry analyzer. Immunophenotyping of whole blood was performed with immunofluorescence staining and subsequent flow cytometric analysis on a BD LSRFortessa. Plasma cytokine analysis was performed using a Millipore multiplex Luminex assay. Results: For hematological and chemistry measurements, pediatric reference ranges deviate largely from adults. Comparison of mother-reared and nursery-reared animals revealed that large differences depend on rearing conditions and diet. Significant differences found between two nursery-reared cohorts (research and colony animals) indicate large influences of experimental factors and anesthetic events on these parameters. Immune cells and cytokine responses presented with distinct patterns for infants depending on age, birth location, and rearing conditions. Conclusions: Our results illustrate how the immune system changed over time and that there was variability among pediatric age groups. Reference ranges of results reported here will support interpretations for how infection and treatment may skew common immune correlates used for assessment of pathology or protection in research studies as well as help veterinarians in the clinical care of infant non-human primates. We highlighted the importance of using age-specific reference comparisons for pediatric studies and reiterated the utility of rhesus macaques as a model for human studies. Given the rapid transformation that occurs in multiple tissue compartments after birth and cumulative exposures to antigens as individuals grow, a better understanding of immunological development and how this relates to timing of infection or vaccination will support optimal experimental designs for developing vaccines and treatment interventions.

Trypanosoma cruzi diversity in naturally infected nonhuman primates in Louisiana assessed by deep sequencing of the mini-exon gene.

BACKGROUND: Trypanosoma cruzi is a zoonotic pathogen of increasing relevance in the USA, with a growing number of autochthonous cases identified in recent years. The identification of parasite genotypes is key to understanding transmission cycles and their dynamics and consequently human infection. Natural T. cruzi infection is present in captive nonhuman primate colonies in the southern USA. METHODS: We investigated T. cruzi genetic diversity through a metabarcoding and next-generation sequencing approach of the mini-exon gene to characterize the parasite genotypes circulating in nonhuman primates in southern Louisiana. RESULTS: We confirmed the presence of T. cruzi in multiple tissues of 12 seropositive animals, including heart, liver, spleen and gut. The TcI discrete typing unit (DTU) predominated in these hosts, and specifically TcIa, but we also detected two cases of coinfections with TcVI and TcIV parasites, unambiguously confirming the circulation of TcVI in the USA. Multiple mini-exon haplotypes were identified in each host, ranging from 6 to 11. CONCLUSIONS: The observation of multiple T. cruzi sequence haplotypes in each nonhuman primate indicates possible multiclonal infections. These data suggest the participation of these nonhuman primates in local parasite transmission cycles and highlight the value of these naturally infected animals for the study of human Chagas disease.

Hydrocephalus after Intrathecal Administration of Dextran to Rhesus Macaques (Macaca mulatta).

Dextrans have been used extensively as medical therapies and labeling agents in biomedical research to investigate the blood-brain barrier and CSF flow and absorption. Adverse effects from dextrans include anaphylactic reaction and dilation of the cerebral ventricles due to administration into the subarachnoid space. This retrospective study describes 51 rhesus macaques (Macaca mulatta) that received dextran intrathecally. The purpose of intrathecal administration was to enable detection of long-lived, dextran-labeled macrophages and to study monocyte-macrophage turnover in the CNS of SIV- or SHIV- infected and uninfected animals by using immunofluorescence. Of the 51 dextran-treated macaques, 8 that received dextran diluted in saline developed hydrocephalus; 6 of these 8 animals exhibited neurologic signs. In contrast, none of the macaques that received intrathecal dextran diluted in PBS developed hydrocephalus. These data suggest the use of saline diluent and the duration of dextran exposure as potential factors contributing to hydrocephalus after intrathecal dextran in rhesus macaques.

Fetal demise and failed antibody therapy during Zika virus infection of pregnant macaques.

Zika virus (ZIKV) infection of pregnant women is associated with pathologic complications of fetal development. Here, we infect pregnant rhesus macaques (Macaca mulatta) with a minimally passaged ZIKV isolate from Rio de Janeiro, where a high rate of fetal development complications was observed. The infection of pregnant macaques with this virus results in maternal viremia, virus crossing into the amniotic fluid (AF), and in utero fetal deaths. We also treated three additional ZIKV-infected pregnant macaques with a cocktail of ZIKV-neutralizing human monoclonal antibodies (nmAbs) at peak viremia. While the nmAbs can be effective in clearing the virus from the maternal sera of treated monkeys, it is not sufficient to clear ZIKV from AF. Our report suggests that ZIKV from Brazil causes fetal demise in non-human primates (NHPs) without additional mutations or confounding co-factors. Treatment with a neutralizing anti-ZIKV nmAb cocktail is insufficient to fully stop vertical transmission.