Protective Efficacy of Lyophilized Vesicular Stomatitis Virus-Based Vaccines in Animal Model.

We evaluated the in vitro effects of lyophilization for 2 vesicular stomatitis virus-based vaccines by using 3 stabilizing formulations and demonstrated protective immunity of lyophilized/reconstituted vaccine in guinea pigs. Lyophilization increased stability of the vaccines, but specific vesicular stomatitis virus-based vaccines will each require extensive analysis to optimize stabilizing formulations.

Influenza C and D Viruses Demonstrated a Differential Respiratory Tissue Tropism in a Comparative Pathogenesis Study in Guinea Pigs.

Influenza C virus (ICV) is increasingly associated with community-acquired pneumonia (CAP) in children and its disease severity is worse than the influenza B virus, but similar to influenza A virus associated CAP. Despite the ubiquitous infection landscape of ICV in humans, little is known about its replication and pathobiology in animals. The goal of this study was to understand the replication kinetics, tissue tropism, and pathogenesis of human ICV (huICV) in comparison to the swine influenza D virus (swIDV) in guinea pigs. Intranasal inoculation of both viruses did not cause clinical signs, however, the infected animals shed virus in nasal washes. The huICV replicated in the nasal turbinates, soft palate, and trachea but not in the lungs while swIDV replicated in all four tissues. A comparative analysis of tropism and pathogenesis of these two related seven-segmented influenza viruses revealed that swIDV-infected animals exhibited broad tissue tropism with an increased rate of shedding on 3, 5, and 7 dpi and high viral loads in the lungs compared to huICV. Seroconversion occurred late in the huICV group at 14 dpi, while swIDV-infected animals seroconverted at 7 dpi. Guinea pigs infected with huICV exhibited mild to moderate inflammatory changes in the epithelium of the soft palate and trachea, along with mucosal damage and multifocal alveolitis in the lungs. In summary, the replication kinetics and pathobiological characteristics of ICV in guinea pigs agree with the clinical manifestation of ICV infection in humans, and hence guinea pigs could be used to study these distantly related influenza viruses. IMPORTANCE Similar to influenza A and B, ICV infections are seen associated with bacterial and viral co-infections which complicates the assessment of its real clinical significance. Further, the antivirals against influenza A and B viruses are ineffective against ICV which mandates the need to study the pathobiological aspects of this virus. Here we demonstrated that the respiratory tract of guinea pigs possesses specific viral receptors for ICV. We also compared the replication kinetics and pathogenesis of huICV and swIDV, as these viruses share 50% sequence identity. The tissue tropism and pathology associated with huICV in guinea pigs are analogous to the mild respiratory disease caused by ICV in humans, thereby demonstrating the suitability of guinea pigs to study ICV. Our comparative analysis revealed that huICV and swIDV replicated differentially in the guinea pigs suggesting that the type-specific genetic differences can result in the disparity of the viral shedding and tissue tropism.

Outer membrane vesicles as nanovaccine candidates against pathogenic Leptospira in experimental Guinea pig model.

Leptospira interrogans serovar Hardjo is a long slender bacterium of size 0.1-0.3 µm × 5-50 µm. It is one of the major causes of bovine leptospirosis and is of economical importance because of the reproductive failure, still birth, abortion, and reduced productivity in cattle. It is also a zoonotic disease-causing infection in humans characterized by headaches, fever, chills, sweats and myalgia, lethargy, aching joints, pulmonary haemorrhages, and death in severe cases. Control of the disease involves antibiotic therapy, management and vaccination, of which immunization is the cheapest and effective means of disease prevention. The present study was developed to isolate and characterize the outer membrane vesicles of Leptospira interrogans serovar Hardjo and to evaluate their vaccine potential in guinea pig model. The OMVs were isolated from the culture by sonication and ultracentrifugation. In transmission electron microscopy, the isolated OMVs appeared as small spherical structures of 50-200 nm size. In Western blot and indirect ELISA, antibodies specific to OMVs were observed as indicative of a good humoral immune response elicited by L. interrogans serovar Hardjo OMV. The OMV-based Leptospira vaccine was able to prevent kidney lesions and renal colonization compared to the control and bacterin vaccinated group as proven by histopathology and PCR.

False positive findings associated with adenoviral vector-based vaccine underscore the regulatory necessity to eliminate abnormal toxicity test.

Accumulating evidence has shown that the abnormal toxicity test (ATT) is not suitable as a quality control batch release test for biologics and vaccines. The purpose of the current study was to explore the optimal ATT experimental design for an adenoviral vector-based vaccine product to avoid false positive results following the standard test conditions stipulated in the Pharmacopoeias. ATT were conducted in both mice and guinea pigs based on methods in Pharmacopeias, with modifications to assess effects of dose volume and amount of virus particles (VPs). The results showed intraperitoneal (IP) dosing at human relevant dose and volume (i.e., VPs), as required by pharmacopeia study design, resulted in false positive findings not associated with extraneous contaminants of a product. Considering many gene therapy products use adeno associated virus as the platform for transgene delivery, data from this study are highly relevant in providing convincing evidence to show the ATT is inappropriate as batch release test for biologics, vaccine and gene therapy products. In conclusion, ATT, which requires unnecessary animal usage and competes for resources which otherwise can be spent on innovative medicine research, should be deleted permanently as batch release test by regulatory authorities around the world.

Ultrasonographic measurements of the normal adrenal glands in guinea pigs (Cavia Porcellus).

Hyperadrenocorticism is an uncommon but important endocrine disease in guinea pigs, but due to its subtle clinical signs and the limited information in veterinary literature, it can be underdiagnosed or misdiagnosed. Ultrasound of the adrenal glands in patients with suspected hyperadrenocorticism can help in identifying adrenomegaly. The purpose of this prospective study was to identify ultrasonographic adrenal gland dimensions in presumed healthy guinea pigs using the same standardized method described for dogs and cats. A conscious ultrasound scan was conducted on twenty client-owned, presumed healthy guinea pigs, and their adrenal glands were measured. A possible correlation between adrenal dimensions with age, sex, and body weight was investigated. The mean length, cranial and caudal pole thickness for the left and right adrenal glands were, respectively, 12.64 ± 2.11 mm and 11.55 ± 1.52 mm; 4.83 mm ± 1.03 mm and 4.69 ± 1.34 mm; 4.8 ± 1.23 mm and 4.04 ± 0.75 mm. The thickness of the left caudal pole was significantly higher than the right (P = 0.02). A significant positive correlation was found between the length of the left adrenal gland and both age (r = 0.46; P = .03) and weight (r = 0.59; P = .01). Statistical correlation between the thickness of each cranial and caudal pole, with age, sex, or weight, was not found. The dimensions provided could prove a useful tool in the clinical evaluation of guinea pigs with suspected hyperadrenocorticism.

New flavonoids with multiple bronchodilator activity pathways from Tephrosia purpurea L. (Pers.) growing in Saudi Arabia.

Total extract of Tephrosia purpurea (T. purpurea) expressed potent ex-vivo bronchodilator effect in isolated Guinea pigs' tracheal muscles. Fractionation of T. purpurea total extract (TPTE) using liquid-liquid technique followed by ex-vivo bronchodilator testing indicated that the activity was trapped to the chloroform (CHCl3) soluble fraction. Phytochemical study of the CHCl3 fraction guided by ex-vivo bronchodilator activity led to the isolation of 7 active flavones of which compounds 1 (epi-Tephroapollin G), 3 (Acetyltephroapollin C), 4 (4''-Dehydroxytephroapollin E), and 5 (epi-Tephroapollin F) were new. Structures were identified using relevant spectroscopic tools including optical rotations and CD data. Compounds 1, 3, 4 and lanceolatin A (6) behaved like papaverine by inhibiting carbachol (CCh) as well as high potassium (K+)-mediated contractions at equivalent concentrations with varied potencies whereas (-)-Tephroapollin G (2) selectively inhibited CCh-mediated contractions but was not found active against high K+. epi-Tephroapollin F (5) and (-)-Pseudosemiglabrin (7) in contrast were significantly more potent to abolish CCh induced contraction when compared with high K+ similar to dicyclomine. Papaverine like dual phosphodiesterase enzyme Ca++ ion inhibitory activities of 1, 3, 4 and 6 were confirmed indirectly by the bolster of the isoprenaline curves against CCh to the left whereas Ca++ inhibitory effect of 1 and 3-7 was confirmed by the rightward deflection of Ca++ concentration-response curves (CRCs) towards right with quashing of the maximum response in same fashion like verapamil. Moreover, compounds 2, 5 and 7 at lower concentrations showed selective blockade of muscarinic receptor similar to atropine. Oral administration of the TPTE, CHCl3 and 7 to guinea pigs significantly protected against bronchospasm induced by 0.2 % histamine aerosol in vivo.

Choroidal blood perfusion could predict the sensitivity of myopia formation in Guinea pigs.

In this study, we explored the predictive role of choroidal blood perfusion (ChBP) and choroidal thickness (ChT) on the development of myopia in guinea pigs. Optical Coherence Tomography Angiography (OCTA) was used to assess the baseline choroidal blood perfusion (ChBP) and choroidal thickness (ChT) in 4-week-old guinea pigs. Refraction and axial length (AL) were measured at baseline. Myopia was induced for one week using form-deprivation (FD) or negative lenses followed by measurements of refraction, axial length and choroidal parameters (ChT and ChBP). The correlations were evaluated between the baseline choroidal values and the magnitude of myopia induced, along with the magnitude of changes in ChT and ChBP after myopia induction. There was a significant correlation between the baseline choroidal parameters and ocular refraction. Myopia induction led to choroidal thinning and less ChBP as well as longer eyes. On the other hand, following exposure to the same non-obstructed visual induction period, the myopic shift was less, and it was associated with thicker choroids and more ChBP at baseline. One week of myopia induction also resulted in thinner choroids and less ChBP, and these declines also correlated with their baseline values. In conclusion, the present study shows that the changes in the baseline choroidal ChT and ChBP parameters are proportional to the magnitude of myopia development and axial elongation in guinea pigs. These significant correlations between baseline ChBP and ChT and myopia development suggest that they may be a viable predictor of this process in guinea pigs.

Effects of blue light exposure on ocular parameters and choroidal blood perfusion in Guinea pig.

PURPOSE: To investigate the impact of different duration of blue light exposure on ocular parameters and choroidal blood perfusion in guinea pigs with lens-induced myopia. METHOD: Three-week-old Guinea pigs were randomly assigned to different light-environment groups. All groups were subjected to 12-h light/dark cycle. The control (NC) group was conditioned without intervention. While lens-induced myopia (LIM) groups had a -10D lens placed in the right eye and 0D in the left eye. The guinea pigs were exposed to increasing periods of blue-light (420 nm) environment for 3,6,9,12 h per day. Changes in refraction, axial length (AL), the radius of corneal curvature (CCR), choroidal thickness (ChT), and choroidal blood perfusion (ChBP)were measured in both LIM-eye and fellow-eye during the second and fourth week of LIM duration. RESULTS: During the first two weeks of the experiment, blue light exposure raised ChBP and ChT, and the effect of suppressing myopia was proportional to the duration of blue light exposure. However, in the fourth week of the experiment, prolonged blue light (12BL) exposure led to a reduction in retinal thickness and the increase in ChT and ChBP ceased. Shorter blue light exposure had a better effect on myopia suppression, with all blue light groups statistically different from the LIM group. CONCLUSION: Exposure to blue-light appears to have the potential to improve ChBP and ChT, thereby inhibiting the development of myopia. we speculate that blue-light inhibits the development of myopia for reasons other than longitudinal chromatic aberration (LCA). However,long-term exposure to blue-light may have adverse effects on ocular development. The next step is to investigate in depth the mechanisms by which the rational use of blue light regulates choroidal blood flow, offering new hope for the treatment of myopia.

MCU Overexpression Rescues Inotropy and Reverses Heart Failure by Reducing SR Ca2+ Leak.

[Figure: see text].

Family first! Influence of parental investment in Guinea pigs (Cavia porcellus) prosocial choices.

Literature often assumed that prosocial behaviours (behaviours that benefit others with or without a cost for the actor) would have evolved many species to improve the effectiveness of parental care (Decety and Cowell 2014). While this hypothesis is rarely questioned at a phylogenetic scale, it was never tested at an individual scale to the best of our knowledge. Therefore, we chose to study the impact of effective parental care on prosociality by comparing the prosocial tendencies of Guinea pigs before mating, during mating and after parturition. We conducted Prosocial Choice Tests on three groups of Guinea pigs (males, multiparous females, and nulliparous females). Subjects had to choose between three options: a prosocial option (subject and recipient being rewarded), a selfish option (only subject was rewarded), and a null option (no reward). Our results showed high prosociality towards their mating partner and their young both in male and in female subjects. Males became selfish towards other males after parturition. Among other interesting results, we found a direct reciprocity phenomenon. We also highlighted an ability in our subjects to consider both the identity and relationship shared with the recipient, such as tolerance (enhancing prosociality), dominance rank (being tested with a dominant recipient increasing selfish responses), and its behaviour (begging calls eliciting prosociality, while threatening ones decreasing it), to choose an option. These findings suggested that prosociality could be modulated by many factors and that the constraints and stakes induced by breeding would highly influence prosocial strategies.

Low doses and short duration of prednisolone administration in guinea pigs experimentally infected with Schistosoma haematobium: Histopathology of liver and lungs.

In our previous study, administration of 5 mg prednisolone for five days pre-Schistosoma haematobium infection in guinea pigs increased susceptibility and produced pathological reactions in the liver and bladder. Since corticosteroids can suppress granuloma formation, maturation, and size, this study sought to investigate if prednisolone given at low doses and short duration can produce granulomatous lesions in the tissues of guinea pigs experimentally infected with S. haematobium. Guinea pigs were shared into six groups: group I and II were the immunosuppressed-infected guinea pigs (I0.5 and I1.5- 20 animals each), group III was the unimmunosuppressed-infected guinea pigs (UI- 20 animals), and group IV, V and VI were the immunosuppressed-uninfected and normal guinea pigs (D0.5, D1.5, and normal- 10 animals each). Prednisolone was given in doses of 0.5 mg/kg and 1.5 mg/kg to the different groups, a day before infection and on day 5 post-infection. The infected groups were subcutaneously injected with 250-300 S. haematobium cercariae. Screening for S. haematobium eggs in urine and fecal samples of animals, and quantitative analysis for leukocyte and red blood cell (RBC) counts in urine samples of guinea pigs began nine weeks post-infection (WPI). Guinea pigs were killed, perfused, worms recovered and sections of the liver, lungs, and bladder excised for histopathological examination at 6, 8, 11, 14 and 16 WPI. S. haematobium eggs were only seen in urine samples of I1.5 at 15 and 16WPI. Although the parasite eggs were seen in fecal samples of all infected guinea pigs from 9WPI, those of UI were sparse and took longer time to hatch. High leukocyte counts were seen in all immunosuppressed groups at 6WPI, which returned to normal levels in D1.5 and D0.5 at 16WPI. At 16WPI, significant numbers of leukocyte and RBC counts were seen in urine samples of I1.5. The immunosuppressed-infected groups had significant numbers of mature and total worm loads than UI group (p > 0.05). However, the worm burden of I1.5 was higher than I0.5 at 14WPI and 16WPI. Non-granulomatous lesions were only recorded in the liver sections of the immunosuppressed-infected animals and in lung sections of UI and I1.5 guinea pigs. Liver lesions seen were hepatocyte degeneration; necrosis; Kupffer cell involvements as hyperplasia, phagocytosis, proliferation; hyperaemia and haemorrhage, and mononuclear leukocyte infiltration. Lung lesions seen in I1.5 at 11-16WPI were hemosiderin depositions and hyperaemia, emphysema and atelectasis, and mononuclear leukocyte infiltrations while in UI, emphysema and mononuclear leukocyte infiltration were seen only at 16WPI. In the immunosuppressed-infected groups, composite liver lesion scores showed that peak lesion severity was at 8WPI and 11WPI in I1.5 and I0.5, respectively. However, there was no significant difference (p = 0.105) in composite liver lesion scores of I1.5 and I0.5. Lung lesion score of UI at 16WPI was significantly higher (p > 0.05) than that of I1.5. Findings from this study show that even at low doses and short duration of administration, corticosteroids can only increase susceptibility of guinea pigs but cannot improve its suitability as experimental models of S. haematobium infection.

Some cardiopulmonary effects of capnoperitoneum in anesthetized guinea pigs (Cavia porcellus): spontaneous ventilation versus intubation and mechanical ventilation.

OBJECTIVE: To compare cardiopulmonary variables and blood gas analytes in guinea pigs (Cavia porcellus) during anesthesia with and without abdominal carbon dioxide (CO2) insufflation at intra-abdominal pressures (IAPs) 4 and 6 mmHg, with and without endotracheal intubation. STUDY DESIGN: Prospective experimental trial. ANIMALS: A total of six intact female Hartley guinea pigs. METHODS: A crossover study with sequence randomization for IAP and intubation status was used. The animals were sedated with intramuscular midazolam (1.5 mg kg-1) and buprenorphine (0.2 mg kg-1) and anesthetized with isoflurane, and an abdominal catheter was inserted for CO2 insufflation. Animals with endotracheal intubation were mechanically ventilated and animals maintained using a facemask breathed spontaneously. After 15 minutes of insufflation, the following variables were obtained at each IAP: pulse rate, respiratory rate, rectal temperature, oxygen saturation, end-tidal CO2 (intubated only), peak inspiratory pressure (intubated only), noninvasive blood pressure and blood gas and electrolyte values, with a rest period of 5 minutes between consecutive IAPs. After 4 weeks, the procedure was repeated with the guinea pigs assigned the opposite intubation status. RESULTS: Intubated guinea pigs had significantly higher pH and lower partial pressure of CO2 in cranial vena cava blood (PvCO2) than nonintubated guinea pigs. An IAP of 6 mmHg resulted in a significantly higher PvCO2 (65.9 ± 19.0 mmHg; 8.8 ± 2.5 kPa) than at 0 (53.2 ± 17.2 mmHg; 7.1 ± 2.3 kPa) and 4 mmHg (52.6 ± 10.8 mmHg; 7.01 ± 1.4 kPa), mean ± standard deviation, with intubated and nonintubated animals combined. CONCLUSIONS AND CLINICAL RELEVANCE: Although the oral anatomy of guinea pigs makes endotracheal intubation difficult, capnoperitoneum during anesthesia induces marked hypercapnia in the absence of mechanical ventilation. An IAP of 4 mmHg should be further evaluated for laparoscopic procedures in guinea pigs because hypercapnia may be less severe than with 6 mmHg.

Lassa Virus Replicon Particle Vaccine Protects Strain 13/N Guinea Pigs Against Challenge With Geographically and Genetically Diverse Viral Strains.

Lassa virus (LASV) causes mild to severe hemorrhagic fever disease in humans. Strain 13/N guinea pigs are highly susceptible to infection with LASV strain Josiah (clade IV), providing a critical model system for therapeutics and vaccine development. To develop additional models of disease, we detail the clinical course in guinea pigs infected with 5 geographically and genetically diverse LASV strains. Two of the developed models (LASV clades II and III) were then used to evaluate efficacy of a virus replicon particle vaccine against heterologous LASV challenge, demonstrating complete protection against clinical disease after a single vaccination dose.

Disruption of MenT2 toxin impairs the growth of Mycobacterium tuberculosis in guinea pigs.

Toxin-antitoxin (TA) systems are abundantly present in the genomes of various bacterial pathogens. TA systems have been implicated in either plasmid maintenance or protection against phage infection, stress adaptation or disease pathogenesis. The genome of Mycobacterium tuberculosis encodes for more than 90 TA systems and 4 of these belong to the type IV subfamily (MenAT family). The toxins and antitoxins belonging to type IV TA systems share sequence homology with the AbiEii family of nucleotidyl transferases and the AbiEi family of putative transcriptional regulators, respectively. Here, we have performed experiments to understand the role of MenT2, a toxin from the type IV TA system, in mycobacterial physiology and disease pathogenesis. The ectopic expression of MenT2 using inducible vectors does not inhibit bacterial growth in liquid cultures. Bioinformatic and molecular modelling analysis suggested that the M. tuberculosis genome has an alternative start site upstream of the annotated menT2 gene. The overexpression of the reannotated MenT2 resulted in moderate growth inhibition of Mycobacterium smegmatis. We show that both menT2 and menA2 transcript levels are increased when M. tuberculosis is exposed to nitrosative stress, in vitro. When compared to the survival of the wild-type and the complemented strain, the ΔmenT2 mutant strain of M. tuberculosis was more resistant to being killed by nitrosative stress. However, the survival of both the ΔmenT2 mutant and the wild-type strain was similar in macrophages and when exposed to other stress conditions. Here, we show that MenT2 is required for the establishment of disease in guinea pigs. Gross pathology and histopathology analysis of lung tissues from guinea pigs infected with the ∆menT2 strain revealed significantly reduced tissue damage and inflammation. In summary, these results provide new insights into the role of MenT2 in mycobacterial pathogenesis.

Transmission and pathogenicity of canine H3N2 influenza virus in dog and guinea pig models.

BACKGROUND: Influenza A virus causes respiratory disease in many animal species as well as in humans. Due to the high human-animal interface, the monitoring of canine influenza in dogs and the study of the transmission and pathogenicity of canine influenza in animals are important. METHODS: Eight-week-old beagle dogs (Canis lupus familaris) (n = 13) were used for the intraspecies transmission model. The dogs were inoculated intranasally with 1 ml of 106 EID50 per ml of canine H3N2 influenza virus (A/canine/Thailand/CU-DC5299/2012) (CIV-H3N2). In addition, 4-week-old guinea pigs (Cavia porcellus) (n = 20) were used for the interspecies transmission model. The guinea pigs were inoculated intranasally with 300 µl of 106 EID50 per ml of CIV-H3N2. RESULTS: For the Thai CIV-H3N2 challenged in the dog model, the incoculated and direct contact dogs developed respiratory signs at 2 dpi. The dogs shed the virus in the respiratory tract at 1 dpi and developed an H3-specific antibody against the virus at 10 dpi. Lung congestion and histopathological changes in the lung were observed. For the Thai CIV-H3N2 challenge in the guinea pig model, the incoculated, direct contact and aerosol-exposed guinea pigs developed fever at 1-2 dpi. The guinea pigs shed virus in the respiratory tract at 2 dpi and developed an H3-specific antibody against the virus at 7 dpi. Mild histopathological changes in the lung were observed. CONCLUSION: The result of this study demonstrated evidence of intraspecies and interspecies transmission of CIV-H3N2 in a mammalian model.

Oral Supplementation with Z-Isomer-Rich Astaxanthin Inhibits Ultraviolet Light-Induced Skin Damage in Guinea Pigs.

The effect of oral supplementation with astaxanthin of different Z-isomer ratios on ultraviolet (UV) light-induced skin damage in guinea pigs was investigated. Astaxanthin with a high Z-isomer content was prepared from the all-E-isomer via thermal isomerization. Intact (all-E)-astaxanthin and the prepared Z-isomer-rich astaxanthin were suspended in soybean oil and fed to guinea pigs for three weeks. The UV-light irradiation was applied to the dorsal skin on the seventh day after the start of the test diet supplementation, and skin parameters, such as elasticity, transepidermal water loss (TEWL), and pigmentation (melanin and erythema values), were evaluated. The accumulation of astaxanthin in the dorsal skin was almost the same after consumption of the all-E-isomer-rich astaxanthin diet (E-AST-D; total Z-isomer ratio = 3.2%) and the Z-isomer-rich astaxanthin diet (Z-AST-D; total Z-isomer ratio = 84.4%); however, the total Z-isomer ratio of astaxanthin in the skin was higher in the case of the Z-AST-D supplementation. Both diets inhibited UV light-induced skin-damaging effects, such as the reduction in elasticity and the increase in TEWL level. Between E-AST-D and Z-AST-D, Z-AST-D showed better skin-protective ability against UV-light exposure than E-AST-D, which might be because of the greater UV-light-shielding ability of astaxanthin Z-isomers than the all-E-isomer. Furthermore, supplementation with Z-AST-D resulted in a greater reduction in skin pigmentation caused by astaxanthin accumulation compared to that of E-AST-D. This study indicates that dietary astaxanthin accumulates in the skin and appears to prevent UV light-induced skin damage, and the Z-isomers are more potent oral sunscreen agents than the all-E-isomer.

Detection and molecular characterization of Cryptosporidium spp. in pet hairless guinea pigs (Cavia Porcellus) from China.

Cryptosporidium spp. are common protozoan parasites that can infect humans and animals worldwide. Recently, the hairless guinea pigs (also called Skinny pigs) were introduced into China as pets. However, Cryptosporidium species and their prevalence in these exotic animals were not studied. In this study, fecal samples were collected from a total of 324 hairless guinea pigs from a pet market and four breeding facilities in four provinces of China. The infection rate of Cryptosporidium was 6.8% (22/324). Three Cryptosporidium species were identified, including Cryptosporidium homai (n = 16), Cryptosporidium wrairi (n = 5), and Cryptosporidium hominis plus C. homai (n = 1). Sequence analysis of the small subunit (SSU) rRNA gene showed that the C. hominis isolate was a C. hominis variant, which mostly infects equine animals. However, the identification of C. hominis was not supported by the analysis of other genetic loci. The C. hominis isolate was characterized as C. homai at both 70-kDa heat shock protein (hsp70) and actin genes, indicating a mixed infection. At the 60-kDa glycoprotein (gp60) gene, subtyping of the C. hominis isolate was not successful. Five C. wrairi isolates were identified as subtype VIIaA13T1, which was previously reported in a guinea pig in the USA. The Cryptosporidium spp. identified in this study have no or low zoonotic potential.

Absence of active systemic anaphylaxis in guinea pigs upon intramuscular injection of inactivated SARS-CoV-2 vaccine (Vero cells).

Background: The safety of novel vaccines against COVID-19 is currently a major focus of preclinical research. As a part of the safety evaluation testing package, 24 healthy guinea pigs were used to determine whether repeated administration of inactivated SARS-CoV-2 vaccine could induce active systemic anaphylaxis (ASA), and to evaluate its degree of severity.Method: According to sex and body weight, the animals were randomly divided into three experimental groups (eight animals per group). The negative control group received 0.9% sodium chloride (priming dose: 0.5 mL/animal; challenge dose: 1 mL/animal); the positive control group received 10% ovalbumin (priming dose: 0.5 mL/animal; challenge dose: 1 mL/animal); and the inactivated SARS-CoV-2 vaccine group received inactivated SARS-CoV-2 vaccines (priming dose: 100 U in 0.5 mL/animal; challenge dose: 200 U in 1 mL/animal). Priming dose administration was conducted by multi-point injection into the muscles of the hind limbs, three times, once every other day. On days 14 and 21 after the final priming injection, a challenge test was conducted. Half of the animals in each group were injected intravenously with twice the dose and volume of the tested substance used for immunization. During the experimental course, the injection site, general clinical symptoms, body weight, and systemic allergic reaction symptoms were monitored.Result: After intramuscular injection of inactivated SARS-CoV-2 vaccine, there were no abnormal reactions at the injection site, clinical symptoms, or deaths. There was no difference in body weight between the groups, and there were no allergic reactions. Conclusion: Thus, inactivated SARS-CoV-2 vaccine injected intramuscularly in guinea pigs did not produce ASA and had a good safety profile, which can provide actual data on vaccine risks and important reference data for clinical research on this vaccine.

Naturally Occurring Osteoarthritis Features and Treatments: Systematic Review on the Aged Guinea Pig Model.

To date, several in vivo models have been used to reproduce the onset and monitor the progression of osteoarthritis (OA), and guinea pigs represent a standard model for studying naturally occurring, age-related OA. This systematic review aims to characterize the guinea pig for its employment in in vivo, naturally occurring OA studies and for the evaluation of specific disease-modifying agents. The search was performed in PubMed, Scopus, and Web of Knowledge in the last 10 years. Of the 233 records screened, 49 studies were included. Results showed that within a relatively short period of time, this model develops specific OA aspects, including cartilage degeneration, marginal osteophytes formation, and subchondral bone alterations. Disease severity increases with age, beginning at 3 months with mild OA and reaching moderate-severe OA at 18 months. Among the different strains, Dunkin Hartley develops OA at a relatively early age. Thus, disease-modifying agents have mainly been evaluated for this strain. As summarized herein, spontaneous development of OA in guinea pigs represents an excellent model for studying disease pathogenesis and for evaluating therapeutic interventions. In an ongoing effort at standardization, a detailed characterization of specific OA models is necessary, even considering the main purpose of these models, i.e., translatability to human OA.

[Trichophyton benhamiae, an emergent zoonotic pathogen in Argentina associated with Guinea pigs: Description of 7cases in Buenos Aires]. / Trichophyton benhamiae, un dermatofito zoofílico emergente en Argentina con reservorio en cobayos: descripción de 7 casos en un hospital de la Ciudad Autónoma de Buenos Aires.

Trichophyton benhamiae is a zoonotic dermatophyte that can cause tinea corporis, tinea faciei and tinea capitis, producing inflammatory lesions, especially in children. In this publication, we describe 7clinical cases of pediatric patients that occurred in our institution between July 2019 and January 2020. All patients underwent a conventional mycological study. The identification of fungi isolates was confirmed by MALDI-TOF MS and sequencing of the ribosomal DNA. T. benhamiae was identified as the etiological agent, whose epidemiological link in all cases was the contact with Guinea pigs. This is the first description of infections caused by T. benhamiae in Argentina. This dermatophyte can be misidentified as other more frequent dermatophytes when performing conventional studies. Molecular technology should be used to reach a definitive diagnosis. It is important to have epidemiological data from patients such as contact with non-traditional pets, especially Guinea pigs, for an adequate presumptive diagnosis of this dermatophytosis.