Histopathologic and antibody responses of rabbits exposed to aerosols containing spores of Aspergillus fumigatus: comparison of single and multiple exposures

Resistance to pulmonary aspergillosis was studied in groups of rabbits exposed to aerosolized spores of Aspergillus fumigatus for 15 minutes on successive days for a total of 10, 7, or 4 exposures or a single exposure. The results of the study demonstrated that exposure of rabbits to spores for 15 minutes on 10 successive days did not result in an accumulation of viable spores in excess of those present in the lungs of rabbits exposed a single time. The tissue response in the lungs of the rabbits exposed at multiple times was more intense than that in the rabbits exposed once, but resolution of the lesions occurred similarly in terms of time and completeness of resolution. The duration of the antibody response as determined by a passive hemagglutination test and by enzyme-linked immunosorbent assay correlated with the number of exposures to spores, in that rabbits exposed 10 or 7 times to aerosolized spores remained positive longer than did those exposed fewer times. The results of the precipitin tests in agar gel were negative in all the rabbits but one.     

Rapid hematogenous dissemination of Aspergillus fumigatus and A. flavus spores in turkey poults following aerosol exposure

Cultures of blood samples taken from 3-week-old turkey poults exposed to aerosolized spores of either Aspergillus fumigatus or A. flavus for 15 min yielded organisms. Aspergillus fumigatus was also isolated from brain and liver tissue samples taken immediately after exposure. Exfoliated cells from the lungs of 10 poults exposed to aerosolized spores of A. fumigatus were allowed to attach to glass slides in tissue culture. Several types of the fixed and stained cells had attached or ingested spores of A. fumigatus. Macrophages were the predominant cell type with ingested spores, although other cell types may be involved in the transport of spores of A. fumigatus into the blood stream after aerosol exposure.     

Pathologic, hematologic, and serologic changes in rabbits given T-2 mycotoxin orally and exposed to aerosols of Aspergillus fumigatus conidia

The influence of immunosuppression by T-2 mycotoxin on the fungal disease aspergillosis was investigated in rabbits. Four groups of rabbits (groups 1A, 1B, 3A, and 3B) were given 0.5 mg of T-2 toxin/kg of body weight/day, PO; in addition, rabbits of groups 3A and 3B were exposed to aerosols of Aspergillus fumigatus conidia from days 7 through 16. Rabbits of groups 2A and 2B were exposed to A fumigatus aerosols, but were not given T-2 toxin, and rabbits of group 0 served as controls. Two rabbits of group 1A, 1 rabbit of group 1B, and 1 rabbit of group 3A died before scheduled necropsy. Rabbits of groups 1A, 2A, and 3A were killed and necropsied on day 17, and the remaining rabbits (groups 0, 1B, 2B, and 3B) were killed and necropsied on day 28. Changes caused by T-2 toxin included leukopenia, marginal anemia, and increased number of and morphologic changes in nucleated erythrocytes by day 21, followed by a regenerative hematologic response. Serum alkaline phosphatase and sorbitol dehydrogenase activities and antibody response to A fumigatus (as measured by an indirect hemagglutination test) were decreased by T-2 toxin ingestion. Rabbits with aspergillosis had leukocytosis, increased PCV, and increased antibody response to A fumigatus. Histologic lesions consisting of centrilobular hepatocellular swelling, portal and periportal fibrosis, and lymphocyte necrosis and/or depletion within secondary lymphoid tissue were observed in most rabbits treated with T-2 toxin. Normal defense mechanisms against A fumigatus infection were compromised by T-2 treatment, as evidenced by the severity and extent of lung lesions, greater number of hyphal elements observed, and greater number of colonies of A fumigatus isolated from rabbits of groups 3A and 3B. There were no significant changes in group-0 rabbits.     

Pathogenesis of Aspergillus fumigatus infection in pigeons in the Sudan.

The pathogenesis of a pigeon isolate of Aspergillus fumigatus in a local breed of pigeons in the Sudan was tested. The spores inoculated intravenously resulted in an acute disease with 100% of mortality within six days. At necropsy, pinpoint and miliary lesions were prominent in the liver, spleen, lungs and kidneys. Histopathological examination detected lesions in the liver, heart, lungs, kidneys, spleen and brain. Hyphae and/or spores were encountered in all these organs. The presence of A. fumigatus was confirmed by reisolation from the liver, lungs and kidneys.     

Serum antibodies to the catalase antigen of Aspergillus fumigatus in cattle

Aspergillus fumigatus is an important agent of mycotic infection in cattle and a potent source of antigens. However, the efficacy of serological diagnosis of aspergillosis in cattle remains controversial. Corbel (1972) and Knudtson et al. (1974) considered a precipitin assay useful as a supplementary test in the diagnosis of mycotic abortion, whereas Wiseman et al. (1984) found the specificity too low to justify its routine use. We have studied 1) the antibody response to the catalase antigen of A. fumigatus in experimentally infected cattle and 2) the prevalence of catalase antibodies and A. fumigatus precipitins in healthy and diseased cattle. The aim was to ascertain how far detection of antibodies to a defined fungal antigen can contribute to the often difficult diagnosis of mycosis.     

Prevalence of mycoplasmas in the respiratory tracts of pneumonic calves.

The prevalence of mycoplasmas in the respiratory tracts of 148 pneumonic calves originating from 25 herds in the Netherlands is reported. Four types of culture media were used to isolate mycoplasmas: solid modified Edward medium, 2 types of Friis media, and A7B differential agar medium. Mycoplasmas were isolated both from nasal swab specimens and lung lavage fluids collected from live calves and from nasal mucosa and lung tissue specimens collected post mortem. All of the mycoplasma strains isolated could be identified as either Ureaplasma diversum (isolated from 80% of 25 herds), Mycoplasma dispar (92%), M. bovirhinis (88%), M. bovis (20%), M. bovigenitalium (4%), M. arginini (16%), or M. canis (12%). Isolation rates of M. dispar and U. diversum were considerably higher from lung lavage fluids than from nasal swab specimens. M. bovis was detected only in fattening herds and not in dairy herds. The respiratory tracts of 75% of the calves examined contained at least 2 mycoplasma species. In total, 25 different combinations of mycoplasma species were detected in specimens collected from noses and lungs. The pathogenic species U. diversum and M. dispar had not been isolated before in the Netherlands.     

Failure to establish infection with Tetratrichomonas sp. in the reproductive tracts of heifers and bulls

Experimental infection of the reproductive tracts of heifers and bulls with Tetratrichomonas sp. isolated from preputial smegma of virgin bulls was attempted. Nine heifers and four bulls were challenged by inoculation of 7 x 10(6) Tetratrichomonas sp. into the vaginal lumen and preputial cavity, respectively. Vaginal mucus and preputial smegma samples were collected and cultured for Tetratrichomonas sp. Heifers were slaughtered in groups of three at 2, 9 and 21 days after inoculation. Two heifers and two bulls infected with Tritrichomonas foetus and two uninfected heifers were used as controls for the model infection. Tetratrichomonas sp. were only isolated in vaginal mucus of 7/9 inoculated heifers at 6h post-inoculation, and genital secretions taken at slaughter time from vagina, uterus and oviduct were cultural negative. Bulls challenged with Tetratrichomonas sp. remained cultural negative. Since Tetratrichomonas sp. survived only a few hours in the female genitalia and did not survive in the male genitalia after experimental challenge, Tetratrichomonas sp. did not colonize the genital tract. These were likely trichomonads from the digestive tract. Collection of clean samples without fecal contamination from the reproductive tract is proposed as a measure to avoid Tetratrichomonas sp. transitory genital infection.     

Contribution to the prophylaxis of chicks aspergillosis: study of the contamination of a hatchery by Aspergillus fumigatus.

Contamination of a hatchery by Aspergillus fumigatus has been studied for 8 weeks from eggs to day old chicks. We have shown that the contamination of the hatchery originates on the egg shell and that each time the eggs are manipulated, spores of Aspergillus fumigatus are thrown into suspension in the air. Thus it seems necessary to bring eggs with as few as possible spores of Aspergillus fumigatus on their shell into the hatchery. Prophylaxis of aspergillosis should be foreseen from the conception of the hatchery: the ventilation system and the internal lay-out should be designed to prevent dispersion and accumulation of Aspergillus fumigatus spores during the processing of the eggs through the hatchery.     

Plasma progesterone concentration in the bovine before abortion or parturition in pregnant animals exposed to Sarcocystis cruzi, Campylobacter fetus, or Aspergillus fumigatus

Pregnant cows in the 4th and 5th month of the gestation were exposed to Sarcocystis cruzi, Campylobacter fetus, or Aspergillus fumigatus. Plasma progesterone concentrations were determined at intervals from before the cows were exposed until they had aborted or calved. The plasma progesterone concentration of the exposed pregnant cattle remained at 3.95 +/- 2.0 ng/ml until 24 to 48 hours before abortion or parturition, when it decreased to below 1.00 ng/ml. This pattern was similar for cattle exposed to each of the infective agents. Thus, changes in progesterone concentrations in bovine plasma cannot be used as a diagnostic tool for fetal distress or fetal death.     

Effects of T-2 mycotoxin ingestion on phagocytosis of Aspergillus fumigatus conidia by rabbit alveolar macrophages and on hematologic, serum biochemical, and pathologic changes in rabbits

Rabbits were given T-2 mycotoxin orally at 0, 0.25, 0.5, and 0.75 mg/kg of body weight/day for 21 days. Only rabbits in the 0.75 mg/kg/day group (4 of 5 rabbits) died. Alveolar macrophages were harvested on day 22 and used for in vitro phagocytosis of killed Aspergillus fumigatus conidia. Cultures included sera from untreated rabbits or rabbits treated with T-2. Phagocytosis was significantly (P less than 0.01) reduced in cultures that used serum from rabbits treated with 0.5 mg of T-2/kg/day and alveolar macrophages from untreated rabbits or rabbits treated with T-2. There was little reduction in phagocytosis when alveolar macrophages from rabbits treated with T-2 and normal serum were used. Ingestion of 0.5 mg of T-2 toxin/kg/day significantly (P less than 0.05) reduced weight gain, serum alkaline phosphatase activity, serum sorbitol dehydrogenase activity, and serum bacteriostasis. Similar changes were found in the 0.75 mg/kg/day group, as well as a significant (P less than 0.05) reduction in PCV, total WBC, and differential leukocyte counts. Neutrophil counts decreased, but not significantly (0.05 less than P less than 0.10). Significant changes were not detected in alanine transaminase activity, aspartate transaminase activity, blood urea nitrogen concentration, or complement hemolytic activity. Histopathologic changes consisting of centrilobular hepatocellular swelling, mild portal and periportal fibrosis and lymphocyte necrosis within secondary lymphoid tissues developed in most rabbits treated with T-2. Thymic atrophy, bile duct reduplication, and lymphocyte depletion of secondary lymphoid tissues developed in the group given 0.75 mg/kg/day.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bacterial flora of the respiratory tracts in chickens with a particular reference to Lactobacillus species.

The effects of three different types of breeding such as isolator, floor, and cage breedings on the bacterial flora of the respiratory tracts (nasal cavity, tongue, pharygolarynx, trachea and air sac) in chickens were determined. Total viable bacterial numbers on the nasal mucus of chickens in the isolator breeding as control group (Group A) aged of 14 days were 10(4.6)/g of autopsy specimen (wet weight), 10(5.7)/g of sample in the cage breeding (Group B) aged of 28 days, and 10(7.0)/g of sample in the floor breeding (Group C) aged of 28 days. Staphylococci and micrococci were predominant bacteria in the nasal cavities of all groups. Total viable numbers of tongue and pharygolarynx were from 10(5.4) to 10(6.5)/g of autopsy specimen. Lactobacilli were the predominant bacteria in pharyngolarynx of chickens. The incidence of staphylococci and micrococci in trachea was lower than those in the another regions. Staphylococci and micrococci dominated in the air sacs of two groups (B and C), but the number and incidence of lactobacilli in the air sacs of chickens were lower than those in the another respiratory tracts. The only clostridia isolation in the air sacs of Group A was observed. A total of 75 strains of Lactobacillus species was isoalted from all respiratory organs and intestine of chickens. These strains were divided into 19 groups. Lactobacillus salivearius subsp. salivarius was the predominant lactobacilli isolated from tongue and pharyngolarynx. Most of isolates from the chicken intestines were mainly identified as the L. acidophilus group and L. reuteri.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of tetracycline sorbate for the treatment of Aspergillus fumigatus infection in broiler chicks.

The efficacy of tetracycline sorbate (Pimafungil; contains 20% tetracycline sorbate w/v) was evaluated for treatment of Aspergillus fumigatus in naturally infected broiler chicks. The drug was administered to a group of 160 infected broiler chicks at 200 mg/l of drinking water, daily and consecutively for 5 days. Another group of 100 infected broiler chicks was kept as untreated controls. The chicks of the treated group showed appreciable improvement in clinical symptoms, mortality, body weight and recovery as shown by absence of gross and histopathological lesions and of the fungus.     

Experimentally induced coronavirus infections in calves: viral replication in the respiratory and intestinal tracts

Eleven 3- to 50-day-old colostrum-deprived gnotobiotic calves and seven 25- to 63-day-old colostrum-deprived conventional calves were allotted into 3 groups. Each group was inoculated with a fecal isolate of bovine coronavirus via different routes: orally/intranasally OR/IN, No. 1 through 8, group 1 calves; OR, No. 9 through 13, group 2 calves; IN, No. 14 through 18, group 3 calves. Nasal swab specimens and fecal specimens were collected daily and were examined for coronavirus antigen by use of direct immunofluorescent staining (nasal epithelial cells) or by use of immune electron microscopy (fecal specimens). All but 4 calves (No. 11, 13, 17, and 18) were euthanatized on postinoculation days (PID) 3 to 7. Calves 11 and 17 became severely dehydrated and died at PID 5. Calves 13 and 18 were evaluated for nasal and fecal shedding of coronavirus through PID 14. Distribution of coronavirus antigen in the respiratory and intestinal tracts of the 14 euthanatized calves was evaluated by use of direct immunofluorescent staining. All calves developed profuse diarrhea by PID 2 to 4; however, calves did not develop clinical signs of respiratory tract disease before euthanasia or death. Inoculated calves shed coronavirus in their feces as detected by use of immune electron microscopy. Infected nasal epithelial cells were detected in all but 2 orally inoculated calves (No. 9 and 10). Route of inoculation influenced the sequence of initial detection of coronavirus antigen from fecal specimens or nasal swab specimens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development of an indirect ELISA for the detection of serum antibodies to Aspergillus fumigatus in captive penguins

Aspergillosis is a significant cause of mortality in captive penguins (Sphenisciformes). An indirect ELISA for the detection of Aspergillus fumigatus-specific immunoglobulin in penguins was developed and standardised by making use of a family-specific antiserum (anti-Aptenodyptes patagonica patagonicus). The results were calculated quantitatively as ELISA units, derived by polynomial regression analysis, and semi-quantitatively as end titres. Serum samples from 61 captive penguins were tested with the assay, and the results were compared with those obtained by counterimmunoelectrophoresis (CIE). The ELISA results correlated with the CIE results only when end titres were reported (R(s) = -0.676, P < 0.002). Fifty-seven of the penguins (93 per cent) were seropositive, but the detection of immunoglobulin did not correlate with clinical disease. At Whipsnade Wild Animal Park, Humboldt's penguins (Spheniscus humboldti) demonstrated higher seropositivity than king penguins (Aptenodyptes patagonicapatagonicus) (P = 0.022), but Humboldt's penguins at Fota Wildlife Park had a significantly higher seropositivity than Humboldt's penguins at Whipsnade (P = 0.035).     

Effects of inhaled fine dust on lung tissue changes and antibody response induced by spores of opportunistic fungi in goats

OBJECTIVE: To investigate the effects of sterile fine dust aerosol inhalation on antibody responses and lung tissue changes induced by Mucor ramosissimus or Trichoderma viride spores following intratracheal inoculation in goats. ANIMALS: 36 weanling Boer-Spanish goats. PROCEDURES: 6 goats were allocated to each of 2 M ramosissimus-inoculated groups, 2 T viride-inoculated groups, and 2 control (tent or pen) groups. One of each pair of sporetreated groups and the tent control group were exposed 7 times to sterilized fine feedyard dust (mean+/-SD particle diameter, <7.72+/-0.69 microm) for 4 hours in a specially constructed tent. Goats in the 4 fungal treatment groups were inoculated intratracheally 5 times with a fungal spore preparation (30 mL), whereas tent control goats were intratracheally inoculated with physiologic saline (0.9% NaCl) solution (30 mL). Pen control goats were not inoculated or exposed to dust. Goats received an IV challenge with equine RBCs to assess antibody responses to foreign antigens. Postmortem examinations were performed at study completion (day 68) to evaluate lung tissue lesions. RESULTS: 5 of 7 deaths occurred between days 18 and 45 and were attributed to fine dust exposures prior to fungal treatments. Fine dust inhalation induced similar lung lesions and precipitating antibodies among spore-treated goats. Following spore inoculations, dust-exposed goats had significantly more spores per gram of consolidated lung tissue than did their nonexposed counterparts. CONCLUSIONS AND CLINICAL RELEVANCE: Fine dust inhalation appeared to decrease the ability of goats to successfully clear fungal spores from the lungs following intratracheal inoculation.