Gerbils and Jirds Flashcards
What gerbils are generally studied in research?
Meriones unguiculatus - Mongolian gerbil
M. libycus - Libyan jird, red-tailed jird
M. crassus - Desert gerbil
M. hurrianae - Indian desert gerbile
M. vinagradovi - Grapevine gerbil
What is the difference between a gerbil and a jird?
Jird is Arabic for gerbil, and is often used for gerbils from Northern African and Central Asia.
Where do all Mongolian gerbils used in research originate from?
Derived from 20 pairs trapped in eastern Mongolia in 1935.
Describe the fur coat of the gerbil tail.
Covering of fur on tail is short near the base and progressively longer toward the tip so it is slightly bushy.
Where are M. unguiculatus found?
Mongolia, adjacent parts of southern Siberia and northern China, and Manchuria
In what environments do gerbils live?
Clay and sandy deserts, bush country, and arid steps.
Are they social? Do they burrow?
Terrestrial. Construct simple burrows in soft soil where they spend most of their time. Tunnels are underground, 2-3 feet in length, and 13 inches in diameter.
What neurological models are gerbils used for in research?
Stroke - Highly susceptible to cerebral infarction following unilateral ligation of one common carotid artery.
Epilepsy - Spontaneous epileptiform seizures mimic those of human idiopathic epilepsy. Seizure-prone and resistant strains have been bred.
Auditory
What are gerbils frequently use in the lab for regarding nematodes? What specific type of nematode?
Maintain nematodes, study pathogenesis, and investigate anthelmintic drugs.
Filarial nematodes
Which age of gerbil is an animal model for Rift Valley fever virus?
Young gerbil. Encephalitis is produced without significant extraneural lesions.
Do gerbils have scent glands?
Yes, a large, ventral abdominal marking gland that is androgen dependent. Attains greater size in the male and develops at an earlier age.
Describe the gerbil adrenal gland.
Cortex produces nearly equal amount of corticosterone and 19-hydroxycorticosterone. Per weight to body weight ration, gerbil adrenal gland is 3x the site of the rat adrenal.
Describe gerbil sexual maturity.
Female vaginal opening at 40-60 days, 30 days before sexual maturity
Males: 70-84 days
Tend to pair-bond, and getting an older female to accept another mate often impossible
What is the gestation period of gerbils?
Nonlactating: 24-26 days
Lactating: 27 days. Always prolonged.
If females bred in postpartum, they delay implantation, and gestation can be as long as 48 days.
Describe young gerbils.
Mean litter size is 3-7. Eat solid foods at 16 days, suckle until day 21, and wean at day 25.
What component must be monitored in gerbil diets? Why?
Fat. Develop high blood cholesterol concentrations on diets containing more than 4% fat.
What is unique regarding gerbil excreta?
Little urine and dry feces.
Why is a low humidity advisable?
Propensity to develop nasal dermatitis at relative humidity above 50%.
What do gerbils require to keep their coats from becoming oily?
Sand baths. Similar to chinchillas, kangaroo rats, grasshopper mice, and degus.
Cage design for gerbils must accommodate what behavior?
Tendency to stand erect on hind limbs. Need solid bottom and appropriate floor-to-lid height.
Describe sore nose in gerbils.
AKA facial eczema and nasal dermatitis. Erythema next to external nares. Progresses to localized alopecia and moist dermatitis. Caused by increased Harderian gland secretion brought about due to stress.
What is the most common fatal infectious disease of gerbils? Describe.
Tyzzer’s caused by Clostridium piliforme.
Sudden death of death after a short period of disease. Presence of multiple foci of hepatic necrosis. Gerbils extremely susceptible. Likely exposed via mouth. can be eliminated to fostering offspring to mice.
What agent caused an epidemic with thickening of the colon and rectum?
Citrobacter rodentium, with lesions similar to transmissible murine colonic hyperplasia.
What gastric agent are gerbils highly susceptible to?
Helicobacter pylori. Causes severe gastritis, gastric ulceration, and intestinal metaplasia. Progression similar to that seen in humans, with early intestinal metaplasia and gastric ulceration replaced by antral gastric adenocarcinoma.
What two nematodes are found in gerbils?
Syphacia obvelata and Dentostomella translucida
There has been no reports of natural of experimental infection of gerbils by what fungal agent?
Dermatophytes.
What occurs in research gerbils fed standard lab rodent diets?
Spontaneous, insidious periodontal disease after 6 months.
10% of animals become obese, with decreased glucose tolerance, elevated serum immunoreactive insulin, and diabetic changes in the pancreas and other organs
Which compound is fatal to gerbils?
Dihydrostreptomycin
Describe seizures in gerbils.
20-40% develop reflex, stereotypic, epileptiform (clonic-tonic) seizures from around 2 months of age. Animals seize in response to sensory stimulation and forced exploratory behavior, but incidence and severity variable. Generally pass in a few minutes with no lasting effects. Incidence and severity often decrease with age, but certain subsets of adults can be induced to seize following prolonged test regiments with progressive severity. Related to a deficiency in cerebral glutamine synthetase.
Describe spongiform lesions in gerbils.
Arise in dendrites and glia in brain stem of Mongolian and M. libycus gerbils. Microcysts and vacuolar neuronal degeneration without astrocytosis. Bilateral, most pronounced in cochlear nucleus, and increase in number, size, and extent with age. Associated with sig. neural degeneration. Result of common excitotoxic mechanisms such as low-frequency noise. Few in feral Mongolian gerbils.
What reproductive condition are gerbils prone to?
Cystic ovaries. Removal of affected ovary does not significantly affect repro performance. Slightly inferior repro performance.
How can the productivity of gerbil breeding colonies be enhanced?
Use only the females that exhibit vaginal opening before 25 days of age as breeder females.
What are the most common neoplasias in gerbils?
SCC of the sebaceous ventral scent gland in males and ovarian granulosa cell tumors in females. Ventral scent marking gland tumors invade locally and can met to lungs and ln
What age-related disorders do gerbils develop?
Chronic interstitial nephritis
Aural cholesteatoma - Canal cholesteatomas
