Comparative Medicine - LABSG



Comparative Medicine

Volume 65, Number 3, June 2015

ORIGINAL RESEARCH

Mouse Models

Gibson et al. Comparison of Cesium-137 and X-ray Irradiators by Using Bone Marrow Transplant Reconstitution in C57BL/6J Mice, pp. 165-172

Domain 3

Primary Species: Mouse (Mus musculus)

 

SUMMARY: Mice are used commonly in transplantation studies involving bone marrow ablation studies. X-ray irradiators have been increasing in popularity due to security issues and expenses associated with gamma irradiators (X-ray irradiators being much cheaper). Mice which were alive at 30 days after engraftment were also alive at 90 days after engraftment and, at the termination of the study (90 days post-engraftment), they had histologically normal bone marrow reconstitution regardless of the radiation source.  However, at 90 days after reconstitution, there was a significant difference between the two irradiators in terms of bone marrow engraftment (B cell, myeloid, and T cell lineages). Specifically, B cell reconstitution was greater after gamma vs X-ray irradiation. The opposite was true for myeloid reconstitution.  T cell reconstitution was greater with X-ray irradiation but the level of mortality was also higher (due to opportunistic infections). In summary, both methods of irradiation resulted in bone marrow ablation sufficient to allow reconstitution. However, the two methods caused distinct physiologic responses which should be considered when choosing the method of irradiation for one’s study. 

QUESTIONS

1.  X-ray irradiators are more expensive than gamma irradiators. T or F

2.  How was the success of the bone marrow transplantation determined?

3. How was the donor bone marrow administered?

4.  Donor bone marrow cells were obtained post-mortem from which long bone?

 

ANSWERS

1.  False. X-ray irradiators cost about 1/6 of a gamma irradiator.

2.   By measuring the percentage of donor-origin cells compared with the recipient cells with success defined as having a chimeric state of at least 85% of donor repopulation.

3. By way of retro-orbital injection

4. Femur

 

Trammell and Toth. Effects of Sleep Fragmentation and Chronic Latent Viral Infection on Behavior and Inflammation in Mice, pp. 173-185

Primary Species: Mouse (Mus musculus)

SUMMARY: This study investigates the so-called ‘sickness behaviors’ (for example, anorexia, anhedonia, reduced social interaction, fatigue) that are common during inflammatory and infectious disease and could be associated with facets of the immune response. To study this relationship, the animals used were murine gamma herpesvirus (MuGHV), a natural pathogen of wild rodents used for experimental model in the study of pathophysiology of an Epstein Barr (EBV)-like γ-herpesvirus infection in mice. Male and female C57BL/6J mice either uninfected or latently infected with MuGHV were exposed to either sleep fragmentation (SF) or control conditions and were measured the effects on behavior and markers of inflammation. The results showed that the exposure of infected male mice to SF during the normal somnolent (light) phase significantly reduced locomotor activity during the subsequent active phase, despite an intervening 6-h rest period. Overall, the infection was associated with significant increases in lung IFNγ and CXC motif ligand (CXCL) 10 in both female and male mice. In both infected and uninfected male mice, exposure to SF was associated with lower levels of IL1β and C-C motif ligand (CCL) 3 in lung. Exposure of infected female mice to SF led to reductions in lung IL2, CXCL1, and CCL 3. In conclusion, compared with control groups, SF could be generally associated with lower concentrations of cytokines in lung. These data can indicate that complex interactions among several host factors might contribute to the inflammatory and behavioral changes associated with viral infection and sleep disruption in a controlled mouse model.

QUESTIONS (True or False)

1. The sickness behaviors are common during infectious disease

2. Infected male mice exposed to SF during light phase increases locomotor activity

3. SF could be associated with lower concentration of cytokines in lung

 

ANSWERS

1. T

2. F

3. T

Braden et al. A Novel α-Hemolytic Streptococcus Species (Streptococcus azizii sp. nov.) Associated with Meningoencephalitis in Naïve Weanling C57BL/6J Mice, pp. 186-195

Domain 3: Management of Spontaneous and Experimentally Induced Diseases and Conditions

Primary Species: Mouse (Mus musculus)

 

SUMMARY: Streptococcus species adversely affect both immunocompetent and immunocompromised mice. As a commensal bacteria these gram-positive cocci inhabit the nose, mouth, intestine, genital tract and skin, in mice, pathogenic streptococci known to affect both immunocompetent and immunocompromised strains are generally β-hemolytic and are associated with suppurative renal, cardiac, splenic hepatic, thoracic, uterine, lymph node and pulmonary lesions. Routine monitoring for β-hemolytic Streptococcus species is recommended by the Federation of European Laboratory Animal Science Associations and is commonly performed by large commercial breeders in the United States. There are only 2 documented case series associated with  α-hemolytic Streptococcus species that resulted in clinical disease in immunodeficient mice.  In this report, the group describes a meningoencephalitis associated with a novel α-hemolytic Streptococcus species in a colony of C57BL/6NCrl mice. 

During 1 year, experimentally naive C57BL/6NCrl weanlings born to timed-pregnant dams from a single vendor demonstrated markedly increased mortality associated with runting, abnormal gait, and decreased activity. The index cases included a 30-d-old male C57BL/6NCrl mouse which was runted, in poor body condition and exhibited neurologic signs including an abnormal hopping gait, tremors and hyperactivity. Four additional male weanlings of approximately the same age but from different dams, from the same colony, were found dead on the same day as the index case was discovered. A CBC analysis and gross and histopathologic evaluation were performed on the live index case. In addition, a section of fixed kidney was submitted for PCR assay.

After the index cases presented, the laboratory reported markedly increased neonatal and weanling death, accompanied by a consistent clinical syndrome of runting, hunched posture, lethargy, abnormal gait and seizure-like activity in mice of the same signalment. During additional questioning, laboratory personnel retrospectively reported mortality as high as 50% in B6 weanlings born to timed-pregnant dams from a single vendor over the prior 3 to 4 months.

 

The group identified a novel α-hemolytic gram-positive bacterium (Streptococcus azizii sp.nov.) from numerous weanling mice delivered by timed-pregnant dams; from 2 clinically affected time-pregnant dams; from 2 asymptomatic timed-pregnant dams; and an adult male mouse procured from a commercial vendor whose colony was enzootically infected. In mice presenting with neurologic signs, the bacterium was consistently associated with a diffuse nonsuppurative meningoencephalitis and ventriculitis in addition to lesions indicative of septicemia. The group speculates that the combination of transport stress, declining maternal antibody, weanling immune incompetence, and the presence of opportunistic bacterium transmitted from either the dam's oral cavity to the urogenital tract (or both) during or after parturition led to neonatal infection and clinical disease. 

 

QUESTIONS

1. What are the two Streptococcus species that common cause meningitis? 

2. What is the proposed pathogenesis of disease caused by Streptococcus? 

3. What are the most common sites that are inhabited by Streptococcus species? 

ANSWERS

1. S. pneumoniae and S. suis

2. Proposed to enter the blood stream after traversing the oral cavity mucosa, presumably with the aid of virulence factors

3. Commensal bacteria inhabiting the nose, mouth, intestine, genital tract and skin

Dholakia et al. Determination of RBC Survival in C57BL/6 and C57BL/6-Tg(UBC-GFP) Mice, pp. 196-201

Domain 3: Research

Primary Species: Mouse (Mus musculus)

SUMMARY: RBC lifespan and senescence are important clinical and research parameters. Many studies of hereditary disorders or erythrocyte metabolism, transfusion medicine or sepsis require knowledge of the characteristics of RBS survival length. Most methods to study RBC longevity require manipulation of the red blood cell through techniques such as biotinylation or use of radioactive isotopes. These may affect red blood cell life span unintentionally. A novel mouse model, the C57BL/6-Tg(UBC-GFP)30Scha/J mouse strain has GFP expression under the ubiquitin promoter. RBCs from this mouse were studied to see whether there was any difference in the longevity between GFP blood cells and biotin labeled RBCs. Further aims of this study were to determine 1) whether sex affects RBC survival; 2) whether RBC survival differs between the biotin method and an alternative method that uses GFP; and 3) whether repeat exposure of mice to biotin results in an antibiotin antibody response or decreased RBC survival. The results suggest no difference in the RBC half-life between male and female C57BL/6 mice (22.9 ±1.2 and 22.4 ±0.9 d, respectively). In addition, RBC half-life did not differ between the biotin- and GFP-based methods (20.5 ±2.1 d and 22.7 ±2.1 d, respectively). Finally, retransfusion of mice 90 d after an initial transfusion with biotin-labeled RBC did not induce detectable antibiotin antibodies nor alter the half-life of transfused biotin-labeled RBC (initial transfusion, 22.0 ±1.2 d; subsequent transfusion, 23.4 ± 1.4 d, respectively).

 

QUESTIONS

1. What reagent forms a strong complex with biotin to allow detection of biotin labeled substrates like RBCs through flow cytometry?

2. In what tissues will a substrate attached to a ubiquitin C promoter be expressed?

3. What is the traditional method to determine RBC survival in humans and what are its drawbacks?

 

ANSWERS

1. Streptavidin

2. All tissues

3. 51Cr radioisotope labeling. Drawbacks include safety and elution from RBC over time.

Marx et al. The Effects of Acute Blood Loss for Diagnostic Bloodwork and Fluid Replacement in Clinically Ill Mice, pp. 202-216

Domain 3: Research

Primary Species: Mouse (Mus musculus)

 

SUMMARY: Despite the great value of diagnostic bloodwork for identifying disease in animals, the volume of blood required for these analyses limits its use in laboratory mice, particularly when they are clinically ill. The authors sought to determine the effects of acute blood loss (ABL) following blood collection for diagnostic bloodwork in healthy mice compared with streptozotocin-induced diabetic and dextran sulfate sodium (DSS)-treated dehydrated mice. The physiologic response to acute blood loss (ABL) has been well characterized in healthy rodents. In healthy animals, the loss of less than 15% of the blood volume initiates compensatory mechanisms, including increased heart rate, arterial and venous contraction, and hormonal changes that maintain cardiac output, venous return, and arterial blood pressure (BP) and collectively prevent overt adverse physiologic changes. Therefore the 10% to 15% blood loss from healthy mice for CBC and serum chemistry analysis is likely to be well tolerated. Conversely, as the percentage of total blood volume lost increases, these compensatory mechanisms become insufficient, and tissue hypoxia, hypercapnia, and acidosis that lead to cell injury and death.

 

Materials and Methods: Young adult (6 to 10 week) male and female C57BL/6J mice (Mus musculus; were maintained on a 12:12-hour light: dark cycle and housed in polycarbonate cages with corncob bedding, with free access to autoclaved food and water. Before the start of the study, the mice were allowed at least 1 week to acclimate to the housing facility and cage environment. The 3 groups of mice included healthy control mice, streptozotocin-induced Diabetes mellitus (DM) mice, and mice dehydrated due to inflammatory bowel disease induced by adding DSS to the drinking water. Diabetes mellitus was induced by treatment with streptozotocin (50 mg/kg daily for 5 consecutive days) at the vendor and was confirmed by blood glucose values that exceeded 300 mg/dL at multiple time points.

 

Results: Acute blood loss caused several mild changes in the control mice, with significant decreases in body weight, temperature, and activity in both experimental groups; increased dehydration and azotemia in the DSS-treated mice; and a significant drop in the blood pressure of the diabetic mice. To determine whether these negative outcomes could be ameliorated, the authors treated mice with intraperitoneal lactated Ringers solution either immediately after or 30 minutes before ABL. Notably, pre-ABL administration of fluids helped prevent the worsening of the dehydration and azotemia in the DSS treated mice and the changes in blood pressure in the diabetic mice. However, fluid administration provided no benefit in control of blood pressure when administered after ABL in the diabetic mice. Furthermore, fluid therapy did not prevent ABL-induced drops in body weight and activity. Although one mouse not receiving fluid therapy became moribund at the 24-hour time point, no animals died during the 24-hour study. This investigation demonstrated that blood for diagnostic bloodwork can be collected safely from clinically ill mice and that preemptive fluid therapy mitigates some of the negative changes associated with this blood loss.

 

QUESTION

1. Streptozotocin is used to create animal models of hyperglycemia and diabetes mellitus (DM). Streptozotocin is a naturally occurring chemical that is toxic to what insulin-producing cell type in the pancreas? 

a.  Alpha cells

b.  Gamma cells

c.  Beta cells

d.  Delta cells

 

ANSWER

c.      Beta cells

Swine Models

Brunner et al. Optical Coherence Tomography of Pulmonary Arterial Walls in Humans and Pigs (Sus scrofa domestica), pp. 217-224

Domain 3

Primary Species: Pig (Sus scrofus)

SUMMARY: Pulmonary arterial hypertension (PAH) is a disorder characterized by progressive elevation of pulmonary pressures which when untreated can lead to chronic right heart failure and death. Currently diagnosis is through right heart catheterization (RHC) to directly measure the pressure in the pulmonary circulation. Angiography during RHC can help with the visualization of pulmonary vessels in real time but its limitations include patient allergic reaction to contrast medium, contrast induced nephropathy, and additionally it is unable to provide information about the extent of vascular wall remodeling or luminal narrowing associated with PAH. Optical coherence tomography (OCT) is an imaging technique that uses a thin wire and near-infrared light to capture micrometer resolution, 3D images from within optical scattering media (e.g., biologic tissue. 

This paper reports the capacity of OCT to obtain both longitudinal and cross-sectional images that provide accurate anatomic information on healthy pulmonary arteries in explanted human lungs and during the pulmonary arterial catheterization of a live adult pig (Sus scrofa domesticus).

OCT was used to study the pulmonary arteries in both human ex vivo lungs and porcine in vivo lungs, both healthy lungs without any PAH. OCT findings were validated by performing vessel histology in both the human and porcine lungs. 

This methodology captures information regarding the extent and influence of vascular remodeling on local patterns of blood flow and provides an anatomic correlate to measures of arterial stiffness and capacitance.

The paper concludes that OCT may facilitate the evaluation of patients with PAH by disclosing the degree of wall remodeling present in pulmonary vessels. Future studies are warranted to determine whether this information complements the hemodynamic and functional assessments routinely performed in PAH patients, facilitates treatment selection, and improves estimates of prognosis and outcome.

 QUESTIONS

1. In this study, what animal species was used as a model to test the capacity of OCT to determine the anatomy of pulmonary arteries? 

a. Phacochoerus africanus

b. Sus scrofa domesticus

c. Sus scrofa

2. Untreated PAH can lead to what serious condition?

a. Pulmonary stenosis

b. Chronic right heart failure

c. Death

d. b and c

e. None of the above

ANSWERS

1. b

2. d

Su et al. Validation of Respiratory Inductance Plethysmography for Measuring Tidal Volume in Swine, pp. 225-231

Domain 1, TT1.4. Anatomy with emphasis on features which have significance with regard to clinical medicine

Primary Species: Pig (Sus scrofa)

 

SUMMARY: The goal of this study was to validate a minimally invasive measurement of tidal volume in pigs. This technique is designed to be used when pigs are anesthetized/minimally restrained and have a face mask (incomplete sealing around the pig’s face), or are intubated with significant leakage in the breathing circuit. The technique of respiratory inductance plethysmography (RIP) correlates the change in amplitude of the ribcage and abdomen during breath with tidal volume and is validated in human adults, newborns, infants, sheep and dogs. The authors wanted to validate RIP method for calculating tidal volume under conditions of both positive-pressure ventilation and spontaneous breathing.

For the first study, pigs were anesthetized and intubated prior to being placed on a mechanical ventilator at different peak inspiratory pressures (5, 10, 15 and 20 cm H20) with a respiratory rate of 10 breaths/min an inspiratory:expiratory ratio of 1:2 and inspired O2 fraction of 10. A calibration curve was produced by plotting the measured tidal volume against the amplitude changes from RIP. RIP was done using insulated self-inductive coils wrapped around each pig’s ribcage (at the level of the 4th-5th rib) and abdomen (just above the navel). Changes in inductive current were used to identify changes in the lengths of the ribcage and abdominal bands during breathing. Following the ventilator study, RIP was assessed under a propofol bolus to induce apnea with manual ventilation at different support pressure levels as well as at the return of spontaneous respiration.

Results: other than one pig with pronounced abdominal breathing, the authors noted a close positive correlation between tidal volume, ribcage excursion and abdominal excursion (R-squared of 0.95-1) for both PPV and spontaneous breathing from individual animals.

QUESTIONS

1.  What minimally invasive technique can be used to measure tidal volume under situations of a leaky anesthetic circuit?

2.   Evaluation of respiratory inductance plethysmography (RIP) in pigs found:

a.  Ribcage excursion is positively correlated with tidal volume

b.   Abdominal excursion is positively correlated with tidal volume

c.  Ribcage excursion is negatively correlated with tidal volume

d. Ribcage and abdominal excursion are positively correlated with tidal volume

e.   RIP is not a reliable measurement for tidal volume in pigs.

3.  T/F: calibration curves obtained during positive pressure ventilation can be used to calculate tidal volume during spontaneous breathing in pigs

 

ANSWERS

1. Respiratory inductance plethysmography (RIP)

2. d

3. T

Nonhuman Primate Models

Rogers et al. Endemic Viruses of Squirrel Monkeys (Saimiri spp.), pp. 232-240

Domain 3: Research; K3:  animal models (spontaneous and induced) including normative biology relevant to the research (e.g., background lesions of common strains

Secondary Species:  Squirrel Monkey (Saimiri spp.) 

 

SUMMARY:  The paper provides an overview of the most common endemic viruses found in species of squirrel monkey.  Squirrel monkeys as a research model have provided important insights into immunology and infectious disease.  As such it is important to have an understanding of common endemic viruses.  As is common with endemic viruses in many species, these endemic viruses often times are only mildly or non-pathogenic in the host species.  Three classes of virus are discussed:  herpesviruses, polyomavirus, and retroviruses.

 

Herpesviruses:  Squirrel monkey herpes virus 1 (SaHV1) is an alpha herpesvirus.  Although it has the potential to cause fatal infections in other primate and non-primate species, in squirrel monkeys it has the potential to cause oral ulcers and plaques similar to herpes virus associated cold sores in humans.  No known zoonotic infections in humans with SaHV1 have been reported.

SaHV2 or herpesvirus saimiri (HVS) is a gamma herpesvirus.  It can establish a lifelong non-pathogenic infection in squirrel monkeys.  In other neotropical primates it can initiate a T-cell leukemia.  Perhaps most notably, HVS has been used to immortalize human T-cells, and it has been used to transform several human T-cell lines.  Although it has been observed to induce lymphoid tumors in other primates, no human diseases have been associated with HVS infections.

SaHV3 is a lycmphocryptovirus, also classified as a gamma herpes virus.  It has some genetic similarities to Epstein Barr virus.

SaHV4 or squirrel monkey cytomegalovirus (SM-CMV) has had little study.

 

Squirrel Monkey Polyomavirus (SMPyV):  Little study has been conducted, but similarities with human polyomaviruses may allow this to model aspects of human polyomavirus infection.

 

Retroviruses:  Squirrel monkey retrovirus (SMRV).  No known disease is associated with SMRV infection, but the ability for a single cell to support replication of SMRV and HVS simultaneously opens the possibility of virus-virus interaction.

Simian foamy virus (SFV) is a well-recognized class of viruses in multiple species, including squirrel monkeys.  No known disease is associated in squirrel monkeys infected with SFV, but there have been evidence of interaction of SFV with simian immunodeficiency virus is a rhesus macaque. 

 

QUESTIONS

1.   What common endemic virus(es) of squirrel monkeys reviewed in this paper are known to be zoonotic and highly contagious with the ability to cause severe illness in humans? 

2.   Which squirrel monkey virus has been used to immortalize T-cell lines?

ANSWERS

1. None.  Squirrel monkeys (and other new world primates) are not carries of Macacine herpesvirus 1 (CHV-1 or B virus).  Nor do the endemic viruses reviewed here transfer easily or cause disease.

2. SaHV4 or squirrel monkey herpesvirus (SHV).

 

Glaze et al. A Comparison of the Pathogenesis of Marburg Virus Disease in Humans and Nonhuman Primates and Evaluation of the Suitability of These Animal Models for Predicting Clinical Efficacy under the ‘Animal Rule,” pp. 241-259

Domain 3: Research, K3 – Animal models including normative biology relevant to the research

 

SUMMARY: This article reviews details and comparisons, including pathogenesis of Marburg virus infections, in humans and common non-human primate models. In the case of diseases like Marburg, human efficacy studies are neither ethical or feasible, the US FDA may grant market approval of a drug or biologic product under the “Animal Rule” through which demonstration of the efficacy of a product can be “based on adequate and well-controlled animal efficacy studies when the results of those studies establish that the drug is reasonably likely to produce clinical benefit in humans.” (21 CFR Part 314.600 for drugs; 21 CFR Part 601.90 for biologic products). In addition, the US Food and Drug Administration’s draft Guidance for Industry: Product Development Under the Animal Rule (May 2014)25 states that the “challenge agent used in animal studies generally should be the same as the etiologic agent that causes the human disease.

 

Marburg virus belongs to family Filoviridae, genus Marburgvirus, and is single species Marburg Marburgvirus, with two virus members Marburg Virus (MARV) and Ravn virus (RAVV). The other genus in family Filoviridae is genus Ebolavirus. Likely host for MARV/RAVV that is probably the cause of Marburg Virus Disease (MVD) in humans is the Egyptian fruit bat (Rousettus aegyptiacus).

 

MARV Infection in Humans: West Germany, Yugoslavia (1967): single source: African green monkeys imported from Uganda. Infected technicians and scientists. 31 patients infected, 7 died within 16d. Symptoms 3-9d post-exposure, malaise, headache, fever, diarrhea, nausea, vomiting, high fever, exanthema/enanthema, lymphopenia, thrombocytopenia, hemorrhage. Gross meninge hyperemia and edematous brain swelling. Splenic red pulp and LN medulla necrosis.

South Africa (1975): 3 cases, index case acquired infection while traveling Rhodesia, and other two during care/travels with index case. Index case died, with other two recovering.

Democratic Republic of Congo (1998 to 2000): Multiple seasonal outbreaks. 118 deaths of 154 patients. Multiple distinct viruses introduced to population. Half of cases from mine workers, others relatives/healthcare in contact to workers. Fever, malaise, headache, nausea or vomiting, anorexia, abdominal pain, diarrhea, myalgia, arthralgia, difficulty breathing, difficulty swallowing or sore throat, hiccups, conjunctival symptoms, lumbar pain, chest pain, cough, and agitation.

 

Uige, Angola (2005): Associated with major hospital. Symptoms similar to above.

Colorado (2008): Single case of woman visiting Python Cave in Uganda. Recovered and confirmed MARV.

 

Holland (2008): Single case of woman visiting two caves in Uganda. She later died and later diagnosed MARV.

 

Sweden (1990-1991): Single case of man returned from Kenya. Recovered after lengthy intensive hospital care and diagnosed with MARV.

 

Kenya (1980 and 1987): 3 cases in Kenya, one died and two recovered. MARV diagnosed by serology. 1987 15-y old boy visits Kitum Cave. Diet and similar lesions to 1967 outbreak.

 

Uganda (2007): 4 miners near Kitaka Cave. 1 died, 3 recovered, with 2 testing positive for MARV.

  

MARV in NHPs: Study in cynomolgus macaques exposed to MARV-Angola (3 high dose, 3 low dose). All high dose euthanized by 8d and low dose 9d. Fever at 4-5d. Rash at 6-7d. Lymphopenia then rebounded. MARV in spleen, LN, esophagus, lung, liver, lung (enlarged lobes with variable congestion and edema, 4 macaques; serosanguinous pericardial fluid, 2 macaques); lymph nodes (enlarged, congested, or hemorrhagic); spleen (enlarged and congestion); liver (enlarged, friable tannish-yellow, all 6 macaques); and intestine (pyloric and duodenal congestion).

Rhesus macaque and African green monkey data represented in fig. 6.

 

Comparison between MARV in humans and NHPs

1.  Human clinical course timeline and exposure route/dose often less detailed or unknown and reliable compared to NHP studies.

2.   NHP symptomatology, such as pain, could not be obtained. Across studies, doses, strains, viral administration.

3.   African green monkeys MARV infection studies did not specific viral variant and was passaged in other species.

4.   Clinical signs, hematology/chemistry, lesions gross and microscopic similar between MARV variants in NHPs and humans.

5.  Fever, lethargy or depression or decreased responsiveness, weight loss or anorexia, and hemorrhage were common for cynomolgus and rhesus macaques and African green monkeys. In addition, rash or petechiae was common in cynomolgus and rhesus macaques, whereas diarrhea and difficulty breathing were prevalent in some studies that included rhesus macaques and African green monkeys.

6.   The time to onset of disease symptoms or signs was variable, ranging from 3 to 9 d in humans, 3 to 10 d in cynomolgus and rhesus macaques, and 2 to 9 d in African green monkeys. Time to death was estimated to be 7 to 22 d, with a mean of 9 d (on the basis of the presumed time of exposure, when known), in humans. The time to death in MARV- and RAVV-infected NHP was reported as 7 to 13 d (mean, 9 d) for cynomolgus macaques, 6 to 12 d (mean, 9 d) for rhesus macaques, and 6 to 13 d (mean, 9 d) for African green monkeys. No differences were found among the NHP species or between humans and NHP regarding time to onset of disease and the ranges and means for time to death. Lymphopenia and thrombocytopenia followed by leukocytosis and platelet recovery were reported for all 3 NHP species. Clinical chemistry evaluations indicated that the liver–biliary system and kidney were targets in humans and cynomolgus and rhesus macaques, given the observed increases in ALT, AST, bilirubin, BUN, and creatinine.

7.  According to the microscopic evaluations, the liver, lymphoid tissues, and kidney were common target organs among humans, cynomolgus and rhesus macaques, and African green monkeys; and humans and cynomolgus monkeys had microscopic lesions of the adrenal gland in common.

QUESTIONS

1.  Which of the following species are used to model Marburg virus infection in humans?

a.  Macaca mulatta

b.   Macaca fascicularis

c.  Chlorocebus aethiops

d.  Aotus spp.

e.   a and b

f.  a and b and c

g.   All of the above

2.  The likely natural host for Marburg Virus is

a.   Choeronycteris mexicana

b.   Corynorhinus townsendii 

c.  Euderma maculatum

d.  Rousettus aegyptiacus

3.   Which of the following species experimentally infected with Marburg virus have similar microscopic lesions in the adrenal gland?

a.  Macaca mulatta

b.  Macaca fascicularis

c.  Chlorocebus aethiops

 

ANSWERS

1. f

2. d

3. b

 [pic]

[pic]

 

CASE REPORT

Nonhuman Primate Models

Uchihashi et al. Use of Femoral Head and Neck Ostectomy and Physical Therapy to Manage Osteoarthritis in a Rhesus Macaque (Macaca mulatta), pp. 260-265

SUMMARY: This article chronicles a case report on an unconventional approach to management of a 10 year old male rhesus macaque presenting with clinical signs associated with osteoarthritis (OA).  The macaque was noted to have a progressive unilateral hind limb lameness, muscle atrophy, severe crepitus, and reduced range of motion (ROM) of the coxofemoral joint; all other aspects of the physical exam were unremarkable. Oral non steroidal anti-inflammatory drug (Carprofen 4mg/kg) was initiated for 14 days; however no improvement was noted after the therapy ended and radiographs were taken. Radiographs revealed osteolysis of the right femoral head, enlarged acetabulum with evidence of osteophyte formation. Blood work and initial biopsy findings ruled out neoplasia or infectious causes.

The authors elected to perform a femoral head ostectomy (FHO), via a craniolateral approach with a partial tenotomy of the deep gluteal muscle to expose the joint capsule. The synovial joint fluid was dark red and had low viscosity; and the femoral neck and head were removed using an osteotome. The excised portions were submitted for histopathology and were negative for bacterial growth, neoplasia or active inflammation. A definitive diagnosis of end-stage degenerative joint disease was made.

Passive ROM exercises were performed with the animal under ketamine sedation and a foraging board was placed on top of cage to encourage the animal use his hind limbs, for 4 months post surgery. The animal was also placed on fish oil capsules, bid, daily and carprofen (2mg/kg), bid, for 3 days and the physical therapy expanded to increase the animal’s active participation. A custom made, computer controlled series of lights and a food pellet dispenser was developed by the researcher as an operant behavioral study also served as a physical therapy. Improvement of mobility and increase of muscle mass of the affected leg were correlated with increased pellets consumed. Fish oil administration, decreased the amount of NSAIDs, necessary to produce an anti-inflammatory effect, by replacing arachidonic acid, and no adverse clinical manifestations were noted. Thus surgical, pharmacological and physical therapy intervention, did improve the macaque’s quality of life and wellbeing.

QUESTIONS

1.  Does concurrent administration of fish oil (omega 3 fatty acids) decrease the amount of NSAID administration needed for an anti-inflammatory effect? True or False.

2.  Clinical manifestations of osteoarthritis may include:

a. Muscular hypertrophy

b.  Crepitus of coxofemoral joint

c.   Muscular atrophy

d.  b and c

e.  All of the above

3.  Which surgical approach did the authors perform for the Femoral Head Ostectomy (FHO)?

a.  Dorsomedial

b.   Caudomedial

c.  Craniolateral

d.   Craniomedial

ANSWERS

1.   True

2.  d

3. c

 

Clemmons et al. Self-injurious Behavior Secondary to Cytomegalovirus-Induced Neuropathy in an SIV-Infected Rhesus Macaque (Macaca mulatta), pp. 266-270

Domain 3       

SUMMARY: A 3.5-y-old female rhesus macaque was infected experimentally with SIV. The animal was maintained in single housing. 8 mo after inoculation, the macaque presented for inappetence, skin abrasion below the left eye, mild bruising below the left brow, epistaxis of the left nostril, a loose deciduous left maxillary canine tooth, and splenomegaly.

 

Serum chemistry revealed hypoproteinemia and an absolute CD4 T cell count of 1452 cells/mm3. Initial differential diagnoses included dermatitis secondary to infectious etiology, tooth root abscess, SIB (self-injurious behaviour), immune mediated dermatitis and neoplasia. Analgesic and antibiotic therapy were initiated with flunixin meglumine and ceftriaxone. Buprenorphine was administered to provide additional pain relief.

 

4 d after initial presentation the lesions remained. The loose deciduous tooth was removed, and there was no evidence of tooth root abscess. There were no changes on repeat radiographs, CBC evaluation, or serum chemistry analysis. Urinalysis values were within normal limits. Blood and urine culture revealed no significant pathogenic bacteria. Treatment with cetirizine was initiated. Antibiotic therapy with enrofloxacin was added for broader spectrum of activity against a potential infection.

 

A behavioural assessment was performed and no abnormal behaviour was recorded. The veterinary staff members observed this animal on multiple occasions actively scratching the affected area of the face. The authors concluded that the facial excoriations were self-inflicted. Euthanasia was elected due to the discomfort that the animal was experiencing despite the pharmacological treatment.

 

Microscopically, there were multifocal facial ulcerations, and subcutaneous nerves had moderate perineural and intraneural neurtrophilic and histiocytic inflammation, with the presence of few cytomegalic cells. The trigeminal nerve fibers, meninges, and adjacent neuropil were infiltrated by numerous neutrophils intermixed with small numbers of macrophages, cytomegalic cells, extravasated erythrocytes, small amounts of fibrinous exudate, and necrotic cellular debris. There were multifocal cytomegalic cells that occasionally contained large, eosinophilic, intranuclear, round to avoid inclusion bodies. The periocular nerves exhibited similar changes, such as neutrophilic to histiocytic inflammation with cytomegalic cells. There was moderate necrosuppurative lymphadenitis with intranuclear viral inclusions. Immunohistochemical staining for CMV (cytomegalovirus) was performed. A few cytomegalic cells labelled positively for RhCMV.

QUESTIONS

1. Which of these statements is false regarding HCMV (human cytomegalovirus)?

a. Immunocompromised hosts and neonates are at high risk

b. It is a common opportunistic infection

c. Adult seroprevalence ranges from 20% to 40%

d. CMV infection is common after immunosuppression in organ-transplant recipients

2. What are the causes of HIV-associated peripheral neuropathy?

a. Direct and indirect effects of the virus itself

b. Opportunistic infections such as HCMV

c. Antiretroviral drug toxicity

d. All the above

3. What of the next diseases have not an increased risk of developing peripheral neuropathy?

a. Diabetes

b. Nutritional deficiency (vitamin B12)

c. Chemotherapy

d. Cushing’s syndrome

e. Lyme disease

f. Leprosy

g. Levodopa administration

            

ANSWERS

1. c. Adult seroprevalence ranges from 50% to 90%.

2. d

3. d

 

Parrula et al. Severe Acquired Idiopathic Thrombocytopenia in a Female Cynomolgus Macaque (Macaca fascicularis), pp. 271-276

SUMMARY: Drug induced thrombocytopenia is a common but serious clinical condition. This diagnosis is made by exclusion of other causes including infectious agents and artifactual decreases related to sample collection and processing. However, there are rare cases of non-drug related unexplainable marked thrombocytopenia as well. A 4 yr old captive bred female cyno presented for veterinary evaluation prior to placement on a pre-clinical study showed a markedly low platelet count that continued to decrease over time. A responsive thrombopoesis was also present with an increased reticulocyte count. Physical exam over the next few days found diffuse pale red discoloration in both inguinal regions, anterior thorax, and multifocal pinpoint areas of erythema or scabs. On day 9, an area of dark discoloration approximately 2cm in diameter on the dorsal surface of the tongue was found. The animal was euthanized on day 11 when it entered menses and had a high risk of bleeding due to the low platelet count. Histopathology found multifocal ulcerative or erosive, hemorrhagic, lymphohistiocytic and neutrophilic glossitis and tonsillitis and all other organs were WNL. The tongue lesion was consistent with Candida albicans and a periodic acid-schiff stain was used to find the dimorphic fungi. Fungal infection was likely related to some form of immunosuppression. The bone marrow showed megakaryotic hyperplasia. No evidence of platelet destruction, consumption, low production, or sequestration or bone marrow suppression. Serologically negative for simian retrovirus, SIV, and simian T-lymphotrophic virus. A false positive for SVV was found originally but was then ruled out with further testing using IFA and PCR. Based on human literature, immune mediated destruction of platelets due to autoantibodies secondary to Candida albicans infection was considered but ruled out when no anti-platelet antibodies on the platelet surface could be detected (an indirect ELISA was used). Therefore, the animal was diagnosed with idiopathic thrombocytopenia. This is the second case in NHP reported and the 1st reported in a cyno.

QUESTIONS

1.  What are the mechanisms to have a decreased platelet count?

2.  What test was used to find the Candida albicans?

a.  Warthin starry stain

b.   GMS

c.  PAS

d.  Wright giemsa

3.   What does SVV stand for?

ANSWERS

1.  Increased consumption, increased destruction, decreased production, and sequestration

2.  c

3.   Simian Varicella

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