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At least 703 records · Page 39Linked to original sources
PubMed1988

Testicular migration, spermatogenesis, temperature regulation and environment of the sheath-tail bat, Taphozous georgianus.

The testes of the common sheath-tail bat of tropical Australia undergo a seasonal migration between the abdomen and the scrotal pouches, while each cauda epididymidis is permanently maintained in the scrotal pouch. Straps of smooth muscle attach to both the cranial and caudal poles of the testes, and these extend cranially to the diaphragm and caudally to the cauda epididymidis. The testicular arteries are not coiled. Among the environmental factors investigated, maximum temperature correlated most significantly with testicular descent, and the number of spermatogonia per bat also correlated most significantly with maximum temperature. Body temperature of a captive bat ranged from 25 to 38 degrees C and this was closely related to body weight and ambient temperature. It seems likely that the scrotal pouch provides a temperature slightly below that of the body and so facilitates sperm storage in the permanently scrotal cauda epididymidis. Migration of the testes probably serves to ameliorate the seasonal temperature fluctuations to which they are exposed while the relatively high correlation between maximum environment temperature and spermatogonial numbers suggests that temperature may be a proximate influence on reproduction in the sheath-tail bat.

Animals↗
PubMed1989

Dynamic aspects of the LHRH system associated with ovulation in the little brown bat (Myotis lucifugus).

Adult female bats were collected from natural roosting sites in pre-ovulatory and post-ovulatory conditions. LHRH neurones of these animals were examined using light and electron microscopic immunocytochemistry, and LHRH tissue contents were measured by radioimmunoassay. Comparisons between the two groups of bats revealed that the number of LHRH perikarya detected immunocytochemically, as well as hypothalamic LHRH content, were significantly reduced in post-ovulatory animals. Distributions of immunoreactive perikarya were, however, strikingly similar in both groups. The reduction in immunoreactive cell number observed after ovulation was therefore not restricted to an anatomically defined subset of neurones, but was evident throughout the population. The projection of LHRH-immunoreactive fibres that extend into the pituitary neural lobe in this species also exhibited changes related to endocrine condition. Morphometric indices of fibre density in the neural lobe were significantly reduced in post-ovulatory bats, as was LHRH content of the lower infundibular stalk and neural lobe. Fine structural study of perikarya revealed complex anatomical interactions between LHRH-immunopositive elements, especially in post-ovulatory bats. These interactions included direct apposition of perikarya, as well as more elaborate networks involving various combinations of perikarya and large- and small-caliber processes. These changes in the LHRH system associated with ovulation suggest reduction of stored peptide within perikarya and depletion from terminals within the lower infundibular stem and neural lobe. Parallel reductions in hypothalamic and neural lobe LHRH content during the periovulatory period support the hypothesis that the neural lobe component of the system contributes to control of gonadotrophin secretion in this species. Finally, increased complexity of anatomical contact between components of the LHRH system may be related to activation of this cell population in spring.

Animals↗
PubMed2000

Detection of dengue virus neutralizing antibodies in bats from Costa Rica and Ecuador.

Neutralizing antibodies for dengue virus serotypes 1 and 2 and serotypes 2 and 3 were detected in 1998 in 12 of 53 (22.6%) and 3 of 10 (30.0%) bats sampled in Costa Rica and Ecuador, respectively. Dengue is a consistent health problem in the two Costa Rican communities in which bats were sampled. The high percentage of bats with neutralizing antibodies to dengue virus in these two Costa Rican communities suggests that bats may become infected with dengue virus. This appears to be the case in Costa Rica and Ecuador.

Animals↗
PubMed2001

Exposure of hooded capuchin monkeys (Cebus apella cay) to a rabid bat at a zoological park.

On 27 May 1999, a big brown bat (Eptesicus fuscus) was discovered on an island exhibit at the Denver Zoo that contained a troop of 15 hooded capuchin monkeys (Cebus apella cay). The monkeys were attacking the bat when it was discovered. The bat was collected and humanely euthanatized without direct handling and submitted to the Colorado Department of Public Health and Environment Virology Laboratory for rabies evaluation. The monkeys had not been vaccinated against rabies virus. The next day, the laboratory confirmed that the bat was positive for rabies. The recommendations from the Colorado Department of Public Health and Environment and the Centers for Disease Control and Prevention were to euthanatize the monkeys or quarantine them and comply with the human nonvaccinated postexposure protocol. A 1-ml dose of a killed rabies vaccine was administered i.m. in the hip on each of days 2, 7, 12, 19, and 33 postexposure, and a single dose of human rabies immune globulin was administered i.m. 5 days postexposure. Blood was collected under anesthesia in order to evaluate the immune response after rabies vaccination from six monkeys 5 days postexposure, six monkeys 19 days postexposure (five of the six monkeys were the same monkeys bled 5 days postexposure), 15 monkeys 67 days postexposure, and 13 monkeys approximately 1 yr postexposure. All of the monkeys developed and maintained levels of rabies virus neutralizing antibody above 0.05 IU/ml by 67 days postexposure. Although a serologic titer of 0.05 IU/ml indicates an adequate human response after rabies vaccination, no similar information is available for nonhuman primates. To date, none of the monkeys has succumbed to rabies.

Animals↗
PubMed2002

Ivermectin toxicosis after topical administration in dog-faced fruit bats (Cynopterus brachyotis).

Forty dog-faced fruit bats (Cynopterus brachyotis) were administered 1 drop of 1% ivermectin topically as part of a routine physical exam and deworming program, and 11 developed sudden generalized paresis. Six of the bats recovered within 24-48 hr, and the remaining 5 were presented recumbent and weak to the University of Florida Veterinary Medical Teaching Hospital. Ivermectin toxicosis was suspected, and the admitted bats died or were euthanatized within 3-5 days of the development of clinical signs despite supportive care. Three of the dead bats had renal tubular necrosis.

Administration, Topical↗
PubMed2004

Species of Eimeria (Apicomplexa: Eimeriidae) from bats (Chiroptera: Vespertilionidae) in central Wyoming.

Feces from 60 bats representing 5 species and 4 genera collected in central Wyoming in 2001 were examined for the presence of coccidia. Two species of Eimeria were identified in 4 bats representing 2 species of Myotis. All infected animals harbored a single species; there was no multispecies infection. Eimeria catronensis was recovered from 3 little brown bats (Myotis lucifugus), and Eimeria californicensis was identified from a single long-legged myotis (Myotis volans). Both represent new geographic records and the second a new host record. Eimeria catronensis-like oocysts were recovered from a single silver-haired bat (Lasionycteris noctivagans). Descriptions and taxonomic summaries for the eimerian species are presented in this study.

Animals↗
PubMed1991

Morphological studies on brown adipose tissue in the bat and in humans of various ages.

This review deals with the comparative observations of brown fat tissue in the bat, a hibernator, and in man, a nonhibernator. In both mammals, the brown fat is distributed in restricted portions of the body and brought into a thermogenetic activity by an acute drop in ambient temperature. Light microscopic examination was performed on the interscapular brown fat of bats captured monthly throughout one year; electron microscopic observations were made using a bat captured in April and another in September. Human perirenal brown fat was investigated light-microscopically on tissues derived from 215 fresh necropsy cases (Japanese) of both sexes aged from one month to 93 years. Brown adipose tissue was recognized only in 162 (75%) of the 215 samples, because brown fat cells were reduced by transformation into white fat cells. Human brown fat cells were classified into six types according to the morphological features of their lipid droplets. These reflect different functional states of intracellular heat production. The Type 1 (D) cell is a fat-depleted brown fat cell with a darkly stained cytoplasm; it is specific to humans. Human perirenal brown fat cells begin to show a transformation into white fat cells already at the infantile stage. This change occurs from the peripheral toward the central portion of the lobule, so that various functioning cell types remain only in the central area of the lobules. In contrast to humans, bat interscapular brown fat cells exhibit regular seasonal changes in size and lipid droplet content, so that the cells could not be classified as in humans into definite types according to the features of their lipid droplets. The most conspicuous difference between brown fat tissue in the nonhibernator and hibernator is that in the latter, white fat cells never occur within the brown fat tissue. In the hibernator, thermogenesis in the brown fat is necessary for both the arousal from hibernation and the maintenance of hibernation as well as rutting. In human perirenal brown fat tissue, darkly stained fat-depleted cells (D) occupy, with other cell types (CR, CR'), an important part in the reversible heat production cycle of the brown fat tissue. The "hypothermic" or "cold syndrome (cold injury)" is a disorder affecting inadequately protected infants in severely cold seasons, accompanied by lethargy, hypothermia and lactation refusal and revealing hemorrhagic pneumonia in necropsy. The brown fat tissue in such infants is composed exclusively of fat-depleted brown fat cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue, Brown↗
PubMed1978

Electron microscope study on the hepatic sinusoidal wall and fat-storing cells in the bat.

The three cell types known to form the hepatic sinusoidal wall were electron microscopically observed in three kinds of bats captured in winter and summer. 1. The cytoplasmic extensions of sinusoidal endothelial cells consisted of continuous thicker parts ("cytoplasmic processes") and discontinuous thinner parts ("sieve plates"). The alternate disposition of the two parts was rather irregular, and the sizes, shapes and spacings of the fenestrae were variable. In the thinner parts with numerous small fenestrae, larger gaps were also mingled. The endothelium was simple-layered and devoid of basal lamina. Interendothelial junctions were found mainly between closely apposed margins of the "cytoplasmic processes" and agreed in structure with the "junctional complex" of WISSE (1970). 2. Kupffer cells, morphologically distinct from the endothelial cells, bulged strongly into the sinusoidal lumen. Provided with many microvillous pseudopods, they were stellate in appearance. They were fixed to the endothelial lining by small junctional areas which occurred between the Kupffer cell body and the "cytoplasmic processes" of the endothelium. 3. Fat-storing cells were located in the Disse's space. They generally contained only smaller amounts of lipid in a few droplets. So-called empty fat-storing cells were numerous, especially in winter bats. The perikaryonal cytoplasm revealed a large Golgi complex and well-developed granular endoplasmic reticulum. The three mesenchymal cell types of the sinusoidal wall possessed the centriole in common within the Golgi complex, but only the fat-storing cell was provided with the single cilium. Fat-storing cells extended cytoplasmic processes ramifying beneath the endothelial lining occasionally surrounding the sinusoids almost completely, and which seemed to reinforce the endothelial lining and to bring about the constriction of the sinusoid. In hypervitaminotic bats that daily received 6,000 I.U. vitamin A for three days, remarkable increase in size and number of lipid droplets was observed in slightly hypertrophic fat-storing cells, and the empty cells disappeared simulating an increased number of fat-storing cells. Suggestion was made of an antidotal function of fat-storing cells against excess vitamin A which might be considered a toxic agent in the broad sense. 4. The Disse's space of bat liver contained plasma cells, lymphocytes and macrophages, the latter too often being under migration through the endothelial fenestrae.

Animals↗
PubMed1978

Occurrence of centrioles in interphasic hepatocytes of bat and chicken.

Occurrence of centrioles in non-dividing hepatocytes was examined by electron microscopy in the bat, Miniopterus schreibersi (Kuhl) and Myotis macrodactylus (Temminck), and the chicken. In both species centrioles were mostly found in the apical hyaloplasmic halo which was distinct in the chicken but rather indistinct in the bat. There was no difficulty in locating centrioles in the hepatocytes of either species. In the chicken centrioles were found in the attenuated apical cytoplasmic areas of 4-6 hepatocytes surrounding the bile canaliculus, giving us the impression that the occurrence of centrioles in non-dividing hepatocytes might be more frequent in the chicken than in the bat. The centrioles found in non-dividing bat and chicken hepatocytes apparently formed diplosomes. Neither multiple centrioles (comprising more than three) nor centriolar replications were found. Single cilium formation from the centrioles was not observed in either species.

Animals↗
PubMed1982

Bats in the belfry: an outbreak of histoplasmosis.

The belfry and attic of a 100-year-old school building located in central Illinois were infested with a colony of big brown bats (Eptesicus fuscus). During the week of April 14, 1980, four workers disturbed the piles of bat droppings in the attic, causing dust to become airborne. Seven to 10 days later, all four workers developed symptoms and chest x-ray findings compatible with acute pulmonary histoplasmosis. Their sera had complement fixation (CF) titers of greater than or equal to 1:32 with fungal antigens and showed M and/or H bands by immunodiffusion tests. An additional 73 persons who had visited the building were also studied, leading to the finding of 16 additional cases of acute pulmonary histoplasmosis, identified on the basis of positive serologies and compatible symptoms. H. capsulatum was isolated from the sputum of one patient and from the soil beneath the hole in the building's eaves where the bats had been entering the attic. Cases were associated with exposure to the attic and with total hours of building exposure when compared with controls. The epidemic curve suggests that sporadic exposures occurred during the spring of 1980, with an epidemic occurring after the bat droppings were disturbed by the four workers.

Animals↗
PubMed2003

Endocrine control of the reproductive activity in hibernating bats.

Bats, Chiroptera, constitute the second largest order of the class Mammalia and vary greatly in habitats, available foods and mating systems. The timing, duration and patterns of reproduction in bats vary considerably among species and different localities. Though much is known about the reproductive phenomena and associated endocrine characteristics of various species, the central mechanism regulating the peculiar delay and asynchrony in reproductive activity remains to be elucidated. The current understanding on the endocrine characteristics and possible mechanism of regulation of the hypothalamo-adenohypophysial-gonadal axis of bats will be reviewed, based mainly on our own studies in hibernating rhinolophid bats.

Animals↗
PubMed1995

Behavioral reactions of the bat Carollia perspicillata to abrupt changes in gravity.

As part of an ongoing survey of the behavioral responses of vertebrates to abrupt changes in gravity, we report here on the reactions of bats (Carollia perspicillata) exposed to altered gravity during parabolic aircraft flight. In microgravity, mammals typically behave as if they were upside-down and exhibit repetitive righting reflexes, which often lead to long axis rolling. Since bats, however, normally rest upside-down, we hypothesized that they would not roll in microgravity. Only one of three specimens attempted to fly during microgravity. None rolled or performed any righting maneuvers. During periods of microgravity the bats partially extended their forearms but kept their wings folded and parallel to the body. Between parabolas and occasionally during microgravity the bats groomed themselves. Both the extended limbs and autogrooming may be stress responses to the novel stimulus of altered gravity. This is the first behavioral record of Chiroptera in microgravity.

Animals↗
PubMed1985

Effect of using mechanical devices for baseball batting on warm-up decrement.

The extent to which different mechanical baseball-batting devices used during a rest affected performance immediately after rest (warm-up decrement) was examined. Difference scores between the average of prerest Trials 8, 9, and 10 and each of 10 postrest trials were used to determine the presence of warm-up decrement. It was predicted that the use of a batting-T and the Batter's Aid machine (in which a batter swings at a ball popped up within the strike zone) would result in superior performance measured as the distance (ft.) a ball was hit and frequency of contacts on postrest performance reducing or eliminating the warm-up decrement. Performance of 33 boys, aged 11 and 12 yr., indicated that only use of the Batter's Aid eliminated warm-up decrement with respect to both the distance and frequency as compared to the batting-T and control groups. In addition, the batting-T condition solicited significantly better performance than the controls on the distance measure but was statistically similar to the controls in frequency of contacts. Also, superior performance was significantly related to heightened heart rate, a physiological index of arousal. A primary explanation of the results focused on the effects of heightened physiological and psychological arousal on warm-up decrement.

Arousal↗
PubMed2005

Bat Nipah virus, Thailand.

Surveillance for Nipah virus (NV) was conducted in Thailand's bat population. Immunoglobulin G antibodies to NV were detected with enzyme immunoassay in 82 of 1,304 bats. NV RNA was found in bat saliva and urine. These data suggest the persistence of NV infection in Thai bats.

Animals↗
PubMed1978

Humoral and cell-mediated immunity to Histoplasma capsulatum during experimental infection in neotropical bats (Artibeus lituratus).

The humoral and cell-mediated immune responses of the large, frugivorus bat, Artibeus lituratus, were studied following intraperitoneal injection of 10 or 10(4) viable mycelial particles of Histoplasma capsulatum. Most bats had both cultural and histologic evidence of disease at autopsy. Utilizing a technique designed to measure the volume of footpad swelling in hypersensitive bats a significant degree of delayed hypersensitivity to histoplasmin was evident in both groups 4 to 6 wk after infection. Precipitating antibodies first appeared in the serum 3 wk after infection, but only in the animals infected with 10(4) viable organisms. Both the double diffusion and counterimmunoelectrophoresis techniques for antibody gave identical results. These findings suggest that A. lituratus is very susceptible to infection with H. capsulatum, and that a mild infection will stimulate delayed hypersensitivity to the organism but only low levels of antibody. The footpad test utilized in this study may be a sensitive and practical method for detecting natural infection in bats.

Animals↗
PubMed1979

Immune responses in bats following intranasal infection with Histoplasma capsulatum.

Groups of bats (Artibeus lituratus) were infected by the intranasal instillation of a suspension of mycelia and spore particles of Histoplasma capsulatum containing either 10(4) or 10(6) viable units. Bats infected with the high dose had viable H. capsulatum in the lungs, liver, spleen and gut as early as 2 weeks post-infection. Complement-fixing antibodies to the organism were detectable 3 weeks after infection, whereas precipitating antibodies were not persent until 5 weeks. Significantly delayed hypersensitivity to histoplasmin was noted at 2 and 4 weeks after infection. By 9 weeks, delayed hypersensitivity had waned, while antibodies could still be demonstrated. The observation that bats are susceptible to respiratory infection with H. capsulatum suggests a mechanism by which the disease may be maintained within a colony. Delayed hypersensitivity appears to be a sensitive, but transient, indicator of active histoplasmosis in bats.

Animals↗
PubMed1982

Contribution of bats to the maintenance of Histoplasma capsulatum in a cave microfocus.

Bracken Cave, a large natural cavern located 25 miles northeast of San Antonio, Texas, serves as nursery roost for millions of Mexican free-tailed bats (Tadarida brasiliensis). Ten days after spending several hours in the cave in early May 1979, three graduate students presented with signs and symptoms compatible with acute pulmonary histoplasmosis. A study was initiated to determine the presence and location of Histoplasma capsulatum in the cave and its inhabitants. The fungus was cultured directly from guano at five of nine sites sampled. Sentinel mice left for several hours at one of three positive sites developed histoplasmosis within 30 days after exposure. Autopsy was done on a total of 28 bats and their lungs, liver and spleen were cultured for viable H. capsulatum. In addition, sera from 58 bats were tested for antibodies to H. capsulatum, using a double diffusion test employing commercial reagents. All bat cultures and sera were negative. We conclude that the students were infected by massive exposure to viable H. capsulatum in aerosols created by disturbing guano deposits near the mouth of the cave. Tadarida brasiliensis contributes to a suitable environment for fungal proliferation, but does not appear to play an active role in the maintenance or dissemination of the fungus in Bracken Cave.

Animals↗
PubMed2000

Australian bat lyssavirus infection: a second human case, with a long incubation period.

In December 1998, a 37-year-old Queensland woman died from a rabies-like illness, 27 months after being bitten by a flying fox (fruit bat). Molecular techniques enabled diagnosis of infection with Australian bat lyssavirus (ABL), the second human case to be recognised and the first to be acquired from a flying fox. It must be assumed that any bat in Australia could transmit ABL; anyone bitten or scratched by a bat should immediately wash the wounds thoroughly with soap and water and promptly seek medical advice.

Adult↗