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Non-human primate models will expedite therapeutics and vaccines for coronavirus disease 2019 (COVID-19) to clinical trials. Here, we compare acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in young and old rhesus macaques, baboons and old marmosets. Macaques had clinical signs of viral infection, mild to moderate pneumonitis and extra-pulmonary pathologies, and both age groups recovered in two weeks. Baboons had prolonged viral RNA shedding and substantially more lung inflammation compared with macaques. Inflammation in bronchoalveolar lavage was increased in old versus young baboons. Using techniques including computed tomography imaging, immunophenotyping, and alveolar/peripheral cytokine response and immunohistochemical analyses, we delineated cellular immune responses to SARS-CoV-2 infection in macaque and baboon lungs, including innate and adaptive immune cells and a prominent type-I interferon response. Macaques developed T-cell memory phenotypes/responses and bystander cytokine production. Old macaques had lower titres of SARS-CoV-2-specific IgG antibody levels compared with young macaques. Acute respiratory distress in macaques and baboons recapitulates the progression of COVID-19 in humans, making them suitable as models to test vaccines and therapies.

Gastrointestinal disease is a frequently encountered problem among captive common marmoset (Callithrix jacchus) colonies. Management can be challenging due to the number of etiologies responsible for gastrointestinal disease in this species, limitations on diagnostic capabilities, and lack of effective treatments. Understanding commonly described GI diseases in the captive marmoset can provide insight on the impact these diseases have on research studies and aid in the development of appropriate management strategies. A review of commonly encountered GI disease processes as well as routinely implicated causes of GI disease in the common marmoset are provided. Current strategies in clinical management of GI disease in the common marmoset, including approaches to colony health, diagnostic testing, and commonly employed treatments are discussed.

Vitamin D(3) (cholecalciferol) is endogenously produced in the skin of primates when exposed to the appropriate wavelengths of ultra violet light (UV-B). Common marmosets (Callithrix jacchus) maintained indoors require dietary provision of vitamin D(3) due to lack of sunlight exposure. The minimum dietary vitamin D(3) requirement and the maximum amount of vitamin D(3) that can be metabolized by marmosets is unknown. Observations of metabolic bone disease and gastrointestinal malabsorption have led to wide variation in dietary vitamin D(3) provision amongst research institutions, with resulting variation in circulating 25-hydroxyvitamin D(3) (25(OH)D(3)), the accepted marker for vitamin D sufficiency/deficiency. Multiple studies have reported serum 25(OH)D(3) in captive marmosets, but 25(OH)D(3) is not the final product of vitamin D(3) metabolism. In addition to serum 25(OH)D(3), we measured the most physiologically active metabolite, 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), and the less well understood metabolite, 24,25-dihydroxyvitamin D(3) (24,25(OH)(2)D(3)) to characterize the marmoset’s ability to metabolize dietary vitamin D(3). We present vitamin D(3) metabolite and related serum chemistry value colony reference ranges in marmosets provided diets with 26,367 (Colony A, N = 113) or 8,888 (Colony B, N = 52) international units (IU) of dietary vitamin D(3) per kilogram of dry matter. Colony A marmosets had higher serum 25(OH)D(3) (426ng/ml (SD 200) versus 215ng/ml (SD 113)) and 24,25(OH)(2)D(3) (53ng/ml (SD 35) versus 7ng/ml (SD 5)). There was no difference in serum 1,25(OH)(2)D(3) between the colonies. Serum 1,25(OH)(2)D(3) increased and 25(OH)D(3) decreased with age, but the effect was weak. Marmosets tightly regulate metabolism of dietary vitamin D(3) into the active metabolite 1,25(OH)(2)D(3;) excess 25(OH)D(3) is metabolized into 24,25(OH)(2)D(3). This ability explains the tolerance of high levels of dietary vitamin D(3) by marmosets, however, our data suggest that these high dietary levels are not required.

Anesthetic and analgesics are essential components of both clinical and research procedures completed in marmosets. A review of current anesthetic and analgesic regimens for marmosets has been complied to provide a concise reference for veterinarians and investigator teams. Published dose regimens for injectable and inhalant anesthetic drugs and analgesic drugs are included. Appropriate physiological monitoring is key to the success of the procedure and perianesthetic options are provided. Although recent publications have refined anesthesia and analgesia practices, our review demonstrates the continued need for evidence-based resources specific to marmosets.