Guinea pigs

Antibacterial activity of plant extracts against Streptococcus equi subsp. zooepidemicus isolates from guinea pigs with lymphadenitis in Ecuador

Lymphadenitis is a commonly occurring and contagious disease in guinea pigs caused by different pathogens, including Streptococcus sp., Staphylococcus sp., and Corynebacterium sp. This study aimed to characterize the bacteria isolated from pus extracted from abscessed mandibular lymph nodes of diseased guinea pigs in Ecuador in 2019 and evaluate the in vitro antibacterial activity of the total extracts of three plant species. Isolates were recovered from three diseased guinea pigs with Lymphadenitis on a farm in Imbabura, Ecuador province. The bacteria were characterized through microbiological, biochemical, and molecular tests as Streptococcus equi subsp. zooepidemicus. Furthermore, the susceptibility of S. equi subsp. zooepidemicus to three plant extracts belonging to the Asteraceae family, Acmella ciliata, Bidens andicola, and Gazania splendens collected in Ecuador, were assessed in vitro by the microdilution method. Our data indicate that all the evaluated extracts showed activity, with a Minimum Inhibitory Concentration (MIC) of 22.50 mg/mL for Acmella ciliata, 11.25 mg/mL for Bidens andicola, and 5.60 mg/mL for Gazania splendens. Bidens andicola extract showed the highest efficacy with a % inhibition of 63.90 at the highest tested concentration (45 mg/mL). This is the first report on the bioactivity of these plant species against S. equi subsp. zooepidemicus.

Interpretation of Serum Analytes for Nutritional Evaluation

Serum micronutrient analysis can provide insight into diet and clinical assessment, despite the complicated interplay between micronutrients and species idiosyncrasies. Approach serum nutrient analytes with skepticism, before jumping to alter diets or offering supplementation. Utilize across species but know that some exotics have exceptions to typical ranges, such as calcium in rabbits or iron in reptiles. Make sure you trust that referenced ranges reflect normal and healthy for that species. Micronutrients are integral to every bodily process, so measurement of serum analytes can tell a story that aids in the clinical picture, when one can recognize what stands out.

Use of a propofol infusion for anaesthetic maintenance in Guinea pigs (Cavia porcellus): a retrospective case series

OBJECTIVE

To retrospectively evaluate the feasibility of a propofol infusion for anaesthetic maintenance in guinea pigs.

STUDY DESIGN

Retrospective case series.

ANIMALS

Client-owned guinea pigs undergoing general anaesthesia.

METHODS

Anaesthetic records of guinea pigs anaesthetized between March 2015 and March 2018 were reviewed. Animals administered a propofol infusion for > 20 minutes were identified and evaluated. Procedure performed, pre-anaesthetic medication, preoperative and intraoperative respiratory rate (fR) and heart rates (HRs), total amount of propofol administered, total anaesthesia and recovery times were extracted from the records and analysed using descriptive statistics and Pearson correlation tests. Data are reported as mean (range).

RESULTS

Records of 14 animals meeting the criteria were identified. Following drug combinations were administered for premedication: butorphanol 0.43 (0.3-0.5) mg kg-1, medetomidine 0.1 (0.05-0.2) mg kg-1 and midazolam 1 (0.5-2) mg kg-1 (n = 3); methadone 0.33 (0.25-0.5) mg kg-1, medetomidine 0.07 (0.01-0.1) mg kg-1 and midazolam 0.66 (0.5-1) mg kg-1 (n = 3); butorphanol 0.5 mg kg-1, medetomidine 0.05 mg kg-1 and ketamine 5 mg kg-1 (n = 2); buprenorphine 0.01 mg kg-1, medetomidine 0.07 (0.04-1) mg kg-1 and ketamine 4 (3-5) mg kg-1 (n = 3); butorphanol 0.5 mg kg-1, alfaxalone 1 mg kg-1 and midazolam 0.5 mg kg-1 (n = 1); and methadone 0.38 (0.25-0.5) mg kg-1, medetomidine 0.08 (0.06-1) mg kg-1 with midazolam 0.75 (0.5-1) mg kg-1 (n = 2). Preoperative and intraoperative HRs were 240 (160-300) and 170 (140-200) beats minute-1, respectively. Preoperative and intraoperative fR were 63 (50-86) and 37 (18-80) breaths minute-1, respectively. The propofol infusion rate was 0.45 (0.17-0.80) mg kg-1 minute-1. Total anaesthesia and recovery times were 60 (25-145) and 17 (8-60) minutes, respectively. A slight correlation was found between total propofol dose infused and recovery time (r = 0.58).

CONCLUSION AND CLINICAL RELEVANCE

Propofol infusions may be a useful alternative to inhalant anaesthetics.

Cutaneous and Subcutaneous Tumours of Small Pet Mammals—Retrospective Study of 256 Cases (2014–2021)

Simple Summary

Several species of small mammals are very popular as companion pet animals and therefore demand professional veterinary care, including proper diagnostic and treatment procedures. The incidence of neoplastic diseases in companion pet animals has increased over time, as it has in humans. The aim of this study was to evaluate the incidence of cutaneous tumours in small mammal pets, including guinea pigs, rats, pet rabbits, ferrets, hamsters, degus, African pygmy hedgehogs, Mongolian gerbils and chinchillas, submitted for histopathology in 2014–2021. Malignant tumours represented the predominant group of cutaneous tumours in rats, African pygmy hedgehogs, degus and chinchillas, and represented a significant percentage of lesions in guinea pigs, pet rabbits, ferrets, hamsters and Mongolian gerbils. We also described the first case of melanocytoma in a pet rabbit, epitheliotropic T-cell lymphoma in a degu, cutaneous histiocytic sarcoma in a Mongolian gerbil, fibrosarcoma in two chinchillas and epithelioid haemangioma in a chinchilla. The incidence of malignant neoplasms among spontaneous integumentary tumours submitted for histopathology is high in many species of small mammal pets. Therefore, each cutaneous tumour should be sampled for further diagnosis and treatment.

Abstract

Since small mammals are gaining popularity as pets in Poland, the number of tumour samples submitted for histopathological examination is quite high. This study was a retrospective analysis of cutaneous and subcutaneous tumours in small pet mammals submitted for histopathology in 2014–2021. The analysis included 256 tumours sampled from 103 guinea pigs, 53 rats, 43 pet rabbits, 21 ferrets, 17 hamsters, 8 degus, 5 African pygmy hedgehogs, 3 Mongolian gerbils and 3 chinchillas. Tumours were diagnosed based on routine histopathology, with additional immunohistochemistry when necessary. The results of this study revealed that the vast majority of cutaneous tumours in guinea pigs were benign, with a predominance of lipoma. Adnexal tumours constituted a significant percentage of cutaneous tumours in guinea pigs (24.3%, with the most common being trichofolliculoma), pet rabbits (46.5%, with the most common being trichoblastoma), ferrets (33.3%, mostly derived from sebaceous glands), hamsters (52.9%, with the most common being trichoepithelioma) and gerbils (66.7%, scent gland epithelioma). Soft tissue sarcomas were a predominant group of tumours in rats (52.8%, with the most common being fibrosarcoma), African pygmy hedgehogs (100%), degus (87.5%) and chinchillas (66.7%). Melanocytic tumours were only sporadically seen in small mammal pets. Mast cell tumours were diagnosed only in ferrets, while epitheliotropic T-cell lymphoma was diagnosed only in a hamster and a degu. In summary, malignant tumours constitute a significant percentage of cutaneous tumours in many species of small mammal pets. Therefore, each cutaneous tumour should be sampled for further cytologic or histopathologic diagnosis.

Use of the guinea pig in studies on the development and prevention of acquired sensorineural hearing loss, with an emphasis on noise

Guinea pigs have been used in diverse studies to better understand acquired hearing loss induced by noise and ototoxic drugs. The guinea pig has its best hearing at slightly higher frequencies relative to humans, but its hearing is more similar to humans than the rat or mouse. Like other rodents, it is more vulnerable to noise injury than the human or nonhuman primate models. There is a wealth of information on auditory function and vulnerability of the inner ear to diverse insults in the guinea pig. With respect to the assessment of potential otoprotective agents, guinea pigs are also docile animals that are relatively easy to dose via systemic injections or gavage. Of interest, the cochlea and the round window are easily accessible, notably for direct cochlear therapy, as in the chinchilla, making the guinea pig a most relevant and suitable model for hearing. This article reviews the use of the guinea pig in basic auditory research, provides detailed discussion of its use in studies on noise injury and other injuries leading to acquired sensorineural hearing loss, and lists some therapeutics assessed in these laboratory animal models to prevent acquired sensorineural hearing loss.

Tooth length and incisal wear and growth in guinea pigs (Cavia porcellus) fed diets of different abrasiveness

Dental diseases are among the most important reasons for presenting guinea pigs (Cavia porcellus) and other rodents to veterinary clinics, but the aetiopathology of this disease complex is unclear. Clinicians tend to believe that the ever-growing teeth of rabbits and rodents have a constant growth that needs to be worn down by the mastication of an appropriate diet. In this study, we tested the effect of four different pelleted diets of increasing abrasiveness [due to both internal (phytoliths) and external abrasives (sand)] or whole grass hay fed for 2 weeks each in random order to 16 guinea pigs on incisor growth and wear, and tooth length of incisors and cheek teeth. There was a positive correlation between wear and growth of incisors. Tooth lengths depended both on internal and external abrasives, but only upper incisors were additionally affected by the feeding of whole hay. Diet effects were most prominent in anterior cheek teeth, in particular M1 and m1. Cheek tooth angle did not become shallower with decreasing diet abrasiveness, suggesting that a lack of dietary abrasiveness does not cause the typical 'bridge formation' of anterior cheek teeth frequently observed in guinea pigs. The findings suggest that other factors than diet abrasiveness, such as mineral imbalances and in particular hereditary malocclusion, are more likely causes for dental problems observed in this species.

Behavior, nutrition, and veterinary care of patagonian cavies (Dolichotis patagonum)

Patagonian cavies (Dolichotis patagonum) are large South American rodents well adapted for cursorial life (well adapted for running). They are monogamous but can live in groups of up to 70 individuals who maintain communal burrows. They are primarily herbivorous and may be maintained on commercially produced rodent or primate diets. Their long, thin legs and skittish nature make them difficult to restrain. Common medical problems include malocclusion of cheek teeth, gastrointestinal parasites, hypertrophic cardiomyopathy, and traumatic leg fractures.

Neuropathogenesis of congenital cytomegalovirus infection: disease mechanisms and prospects for intervention

Congenital cytomegalovirus (CMV) infection is the leading infectious cause of mental retardation and hearing loss in the developed world. In recent years, there has been an improved understanding of the epidemiology, pathogenesis, and long-term disabilities associated with CMV infection. In this review, current concepts regarding the pathogenesis of neurological injury caused by CMV infections acquired by the developing fetus are summarized. The pathogenesis of CMV-induced disabilities is considered in the context of the epidemiology of CMV infection in pregnant women and newborn infants, and the clinical manifestations of brain injury are reviewed. The prospects for intervention, including antiviral therapies and vaccines, are summarized. Priorities for future research are suggested to improve the understanding of this common and disabling illness of infancy.

GUINEA PIGS

This chapter deals with the health and medical care issues of guinea pigs. Guinea pigs have wide bodies with short limbs. They have a short, flat nose, laterally placed eyes, and hairless external pinnae. The dentition of the guinea pig is described as aradicular hypsodont. Guinea pigs are best housed in well-ventilated, wire-sided cages with solid bottoms. If housed indoors, guinea pig enclosures do not require a cover, as these animals do not typically jump or climb. Heavy food containers are recommended to make dumping of the receptacle more difficult. All food containers should be easy to disinfect and should be cleaned regularly, because guinea pigs have a habit of soiling their food bowls. These animals, native to the Andes Mountains, are very susceptible to hyperthermia and should never be housed in temperatures greater than 80°F. High humidity can also exacerbate a guinea pig's sensitivity to elevated temperatures by increasing the heat index. Guinea pigs often do not exhibit clinical signs early in a disease process. Therefore, a thorough physical examination can be extremely useful in determining the overall health status of the animal.

Nonprimate models of congenital cytomegalovirus (CMV) infection: gaining insight into pathogenesis and prevention of disease in newborns

Congenital and perinatal infections with cytomegalovirus (CMV) are responsible for considerable short- and long- term morbidity in infants. CMV is the most common congenital viral infection in the developed world, and is a common cause of neurodevelopmental injury, including mental retardation and sensorineural hearing loss (SNHL). Antiviral therapy has been shown to be valuable in ameliorating the severity of SNHL, but CMV disease control in newborns ultimately depends on successful development of a vaccine. Because CMVs are extremely species specific, preclinical evaluation of vaccines must be performed in animal models using the appropriate CMV of the animal being studied. Several small animal models available for CMV vaccine and pathogenesis research are described. The discussion focuses on the guinea pig model because guinea pig cytomegalovirus (GPCMV), which crosses the placenta and causes infection in utero, is uniquely useful. Examination of vaccines in the GPCMV and other nonprimate models should provide insights into the determinants of the host response that protect the fetus, and may help to prioritize potential vaccine strategies for use in human clinical trials related to this important public health problem.

Alveolar septal deposition of immunoglobulin and complement parallels pulmonary hemorrhage in a guinea pig model of severe pulmonary leptospirosis

Human patients suffering from leptospirosis present with a diverse array of clinical manifestations, including the more severe and often fatal pulmonary form of the disease. The etiology of pulmonary hemorrhage is unclear. Isolates of Leptospira acquired from patients suffering from pulmonary hemorrhage were used to develop a guinea pig model of pulmonary hemorrhage. Gross findings post-infection confirmed extensive hemorrhage in the lungs and on peritoneal surfaces as the likely cause of death. Immunohistochemistry confirmed the presence of large numbers of leptospires in kidney, liver, intestinal tissues, and spleen, but few inflammatory cells were seen. In marked contrast, few leptospires were detected in infected hemorrhagic lung tissue. Blood chemistries and hematology did not reveal the etiology of the hemorrhage observed. There was no chemical or microscopic evidence for disseminated intravascular coagulation. To ascertain an immunopathologic role during disease, immunofluorescence was performed on infected lung tissues and confirmed the presence of IgM, IgG, IgA, and C3 along the alveolar basement membrane. This suggests that an autoimmune process may be the etiology of fatal pulmonary hemorrhage in leptospirosis.

Rodent therapeutics

Although the number of rodents kept as pets is increasing in the United States, much of the veterinary information that is known regarding their care is derived from laboratory animal medicine. This article describes individual species variation of medication delivery methods and the associated risks of antibiotic usage. A comprehensive formulary is also included.

Small mammal critical care

In emergency situations, veterinarians often are presented with critical patients of any species. The principles for critical care in traditional species such as the dog or cat can be applied to other small mammals. Although there are many unique aspects of the anatomy and physiology of different species, emergency care of small mammals can be instituted with the adaptation of products found in many general practices. Careful assessment of the patient, prioritization of the injuries, and rapid intervention can be life saving in any species.