Immune response to pulmonary injection of Pasteurella haemolytica-impregnated agar beads followed by transthoracic challenge exposure in goats

A method of inducing Pasteurella haemolytica serotype 1 (Ph1) lung infection in goats, using low numbers of bacteria and without impairing host immunity, was developed. Two trials were conducted. Results of trial 1, using 10 principals (Ph1 agar beads) and 6 controls (agar beads alone), indicated that Ph1 organisms imbedded in agar beads could survive host lung defenses for 32 days. Results of trial 2 indicated that lung immunity in the inoculated goats (principals) was high and they were more protected than controls against a transthoracic challenge of Ph1 (1.18 x 10(7) colony-forming units) injected into a lung of each goat on posttreatment day 35. When comparing challenge-exposed principals with controls, the controls developed rectal temperatures above normal for a longer time, duration of anorexia was longer, and signs of depression were seen. The controls developed large areas of consolidated lung tissue, more Ph1 isolates were recovered from nasal turbinates and lung tissue, and higher Ph1 concentrations were found in the lungs. The serum Ph1 indirect hemagglutination antibody titers in the principals of both trials increased, compared with titers in controls. Principal goats in trial 2 had higher Ph1 indirect hemagglutination antibody titers after injection of Ph1-impregnated agar beads and less severe lung lesions after challenge exposure than did controls. The small pneumonic consolidated lesions in the principals, compared with extensive lesions in controls after Ph1 challenge exposure, indicated a high degree of immunity after exposure to Ph1 organisms imbedded in agar beads.     

Effects of inoculations with Eimeria zuernii on young calves treated with decoquinate or narasin with or without dexamethasone

Sixteen 7-week-old Holstein male calves were inoculated with sporulated oocysts of Eimeria zuernii. Four calves (controls) were euthanatized and necropsied at 14 and 20 days after inoculation (DAI). Two calves were treated with 20 mg of dexamethasone (IM) on 13, 14, and 15 DAI and euthanatized and necropsied 17 DAI and 2 calves were given similar treatments and necropsied 20 DAI. The 8 other calves were euthanatized and necropsied 20 DAI. Two were started on the anticoccidial drug decoquinate in feed 13 DAI; 2 others were given decoquinate on the same schedule plus dexamethasone on 13,14, and 15 DAI. Two calves were given the antibiotic narasin in feed beginning 13 DAI and 2 calves were given parasin on the same schedule plus dexamethasone on 13,14, and 15 DAI. All calves, except 2 controls necropsied 14 DAI and 4 calves given decoquinate, discharged moderate-to-large numbers of oocysts in feces and had moderate-to-serve changes in fecal consistency. Histologic examinations revealed large numbers of endogenous stages in tissues of calves treated or not treated with dexamethasone. Few endogenous stages were observed in tissues from calves that were given decoquinate or decoquinate plus dexamethasone. Calves given narasin or narasin plus dexamethasone had moderate-to-large numbers of endogenous stages in the tissues.     

Immunity to sarcocystosis: Modification of intestinal coccidiosis,and disappearance of sarcocysts in dairy goats

Fifty, 2–3 month old dairy goats were each vaccinated orally with 10000 sporocysts of Sarcocystis capracanis and 25 age-matched goats served as uninoculated controls. Groups of vaccinated and control goats were challenged with lethal doses of S. capracanis at 95, 113, 205, and 274 days post-vaccination. Vaccinated goats developed subclinical sarcocystosis. Twenty-three vaccinated goats and 1 control goat died of intestinal coccidiosis and bacterial pneumonia, 15–118 days after vaccination. Myositis and degenerating sarcocysts were seen in muscles of goats necropsied at 90–186 days postvaccination. Very few, or no sarcocysts were seen in goats necropsied at 272 and 332 days post-vaccination. Vaccinated goats survived a lethal challenge inoculation indicating persistent protective immunity.     

Use of a toxoid vaccine to protect goats against intradermal challenge exposure to Corynebacterium pseudotuberculosis

Two groups of male, 9-week-old goats (5 goats/group) were vaccinated subcutaneously with formalized exotoxin of Corynebacterium pseudotuberculosis, with Freund's incomplete adjuvant. Each goat was given 2 vaccinations, 2 weeks apart. At each vaccination, each group 1 goat was given 0.5 ml of toxoid, and each group 2 goat was given 1 ml of toxoid. Twenty days after the 2nd vaccination, vaccinated goats and 5 nonvaccinated 12-week-old goats (controls) were inoculated intradermally (challenge exposed) with live C pseudotuberculosis, monitored for 13 weeks, and euthanatized. At necropsy, 5 of the 10 vaccinated goats did not have C pseudotuberculosis lesions, 3 had abscesses limited to the inoculation site and draining lymph node, and 2 had disseminated bacterial lesions. Of the 5 nonvaccinated controls, 4 had disseminated abscesses and 1 had a single abscess in an internal node. Serologically, 9 of the 10 vaccinated goats developed positive (greater than or equal to 1:8) antibody titers against the exotoxin within 1 week after inoculation; the 10th goat seroconverted 2 weeks after inoculation, whereas control goats required 3 weeks to develop a positive antibody response. Therefore, early during an infection with C pseudotuberculosis, antibodies against the exotoxin may protect a goat against spread of the organism. All goats were injected intradermally before challenge exposure, 10 days after challenge exposure, and at 4, 8, and 12 weeks after challenge exposure with a skin-test reagent composed of fragmented bacterial cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of recombinant bovine interferon gamma and dexamethasone on pneumonia attributable to Haemophilus somnus in calves

The influence of recombinant bovine interferon gamma (rBoIFN-gamma) treatment on resistance of clinically normal and dexamethasone-treated calves to Haemophilus somnus infection was evaluated. Four groups of 6 calves each were treated with saline solution (controls), dexamethasone (0.04 mg/kg of body weight/for 3 days), rBoIFN-gamma (2 micrograms/kg for 2 days), or dexamethasone and rBoIFN-gamma (aforementioned dosages). All treatments were started 24 hours before intrabronchial challenge exposure with 5 x 10(9) colony-forming units of H somnus. Rectal temperature and WBC count were monitored daily. Two of the dexamethasone-treated calves died of pneumonia 4 days after challenge exposure and were necropsied. All other calves were euthanatized and necropsied 7 days after challenge exposure. All calves had pneumonia of variable intensity. Dexamethasone-treated calves had increased volume of pneumonic lung (P less than 0.05) and increased severity of pneumonia, compared with control calves. Recombinant bovine interferon gamma treatment resulted in reduction in pneumonic lung volume and severity of pneumonia in dexamethasone-treated calves (P less than 0.05), although it did not influence severity of pneumonia in nondexamethasone-treated calves.     

Recovery of transmissible gastroenteritis virus from chronically infected experimental pigs.

Transmissible gastroenteritis (TGE) virus was reisolated from pulmonary and intestinal tissues from 6 of 9 chronically infected experimental pigs (principals) necropsied 30 to 104 days after inoculation. Tissue homogenates (lung and small intestine) from the principals were prepared and inoculated into 3- to 5-day-old gnotobiotic pigs. The virus reisolated from the tissue homogenates produced a milder disease on 1st passage and a more severe disease on 2nd passage. The chronically infected experimental pigs (principals) developed serum-neutralization titers to TGE of 1:30 to 1:525. There appeared to be no relationship between serum titers and reisolation of TGE virus from the 9 principals. The persistence of virus in lung or intestine to 104 days indicates the recovered (or carrier) pig may be considered the primary source of TGE virus infection.     

Distribution of Brucella abortus organisms in calves after conjunctival exposure

Thirty calves (3 to 4 months old) were exposed conjunctivally to a pathogenic strain of Brucella abortus. Calves were euthanatized and necropsied at postexposure hours 2 and 4, and at postexposure days (PED) 1, 4, 7, 14, 21, 42, and 49. Selected ocular, pharyngeal, and lymphoid tissues were cultured bacteriologically for brucellae to determine organism distribution. Brucella abortus organisms initially localized in the third eyelids, bulbar conjunctivae, and parotid lymph nodes and were detected in these structures until PED 42, 21, and 49 respectively. In calves euthanatized at PED 7, organisms were in other cranial lymph nodes (mandibular and retropharyngeal), and in calves euthanatized at PED 21, organisms were isolated from peripheral lymphoid tissues. Brucellae were not isolated from mesenteric and bronchial lymph nodes and from the spleen until PED 21. The pattern of isolation indicated that conjunctival exposure probably resulted in entrance of brucellae into the host via ocular tissues.     

Experimental and clinical investigations of the use of carbon fiber sutures in equine tendon repair

Braided carbon fiber sutures were used to repair surgically transected or lacerated digital flexor tendons of 20 mature horses (10 experimental and 10 clinical cases). In addition, 4 experimental horses had tenectomies that were not surgically repaired; these served as controls for the horses with carbon-implanted tendons. Six of the 10 clinically affected horses were returned to their intended use; 2 were euthanatized because of complications and 2 were still recuperating. The experimental horses were euthanatized at 12 days and 1, 2, 4, 8, and 12 months. Tendon scars were structurally and functionally similar in all of these horses. The main histologic difference between the controls and principals was the more extensive remodeling in the latter group at 8 months.     

Pathogenicity of Salmonella enteritidis phage types 4, 8, and 23 in broiler chicks.

Four hundred fifty day-old Hubbard broiler chicks were subdivided into 15 groups of 30 chicks each. Six groups of chicks received 0.5 ml of broth culture containing 5 x 10(6) colony-forming units (CFU) of Salmonella enteritidis (SE) phage types (PTs) 4, 8, and 23 by crop gavage. Similarly, six other groups received 0.5 ml containing 5 x 10(8) CFU of SE. One group was inoculated with 0.5 ml containing 5 x 10(6) CFU of Salmonella pullorum, and another group received 0.5 ml containing 5 x 10(8) CFU of S. pullorum. A group of 30 chicks were kept as uninoculated controls. Chicks were observed daily for clinical signs and mortality. All birds were weighed at 7, 14, and 21 days postinoculation 21 (DPI). Four chicks were randomly selected from each treatment group, euthanatized, and necropsied at 7 and 14 DPI. Gross lesions were recorded and selected tissues were collected for histopathology. The higher rates of illness and mortality were observed in chicks inoculated with 5 x 10(6) and 5 x 10(8) CFU of S. pullorum, followed by SE PT4 of human origin and SE PT4 of chicken origin. Moderate to high mortality was observed in chicks inoculated with the higher dose of SE isolates that belonged to PT8 and one SE of PT23. Variable mortality was evident in groups inoculated with the lower dose of salmonella. The most consistent gross and histopathologic changes, including fibrinous pericarditis and perihepatitis, were seen in the dead birds from various treatment groups. The lower mean body weights were present in all treatment groups compared with uninoculated controls. No illness or mortality was observed in uninoculated control groups.     

Reproductive evaluation of male beagles and the safety of ivermectin

Ivermectin had no adverse effects on spermatogenesis, fertility, or reproductive performance of Beagle dogs when administered orally at 600 micrograms/kg (0.6 mg/kg) of body weight monthly for 8 treatments. Semen was collected every 3 days from 28 days before treatment began until 83 days thereafter from 6 ivermectin-treated Beagles and 6 similar water-treated controls (38 collections/dog). All dogs were then bred to 2 nontreated bitches each; litter size, birth weights, and pup abnormalities and mortalities were evaluated. After all pups were whelped, each dog was euthanatized and necropsied, and the testis and epididymis were examined microscopically.     

Experimental transmission of Pasteurella multocida 6:B in goats

Haemorrhagic septicaemia (HS) is an acute disease of cattle and buffaloes caused by Pasteurella multocida 6:B. Outbreaks of the disease have been closely associated with carrier animals that transmit the organism to susceptible animals during stressful condition. This study was conducted to determine whether goats exposed intranasally to P. multocida 6:B can transmit the organism to contact goats. Thirty-six healthy local Katjang goats were divided into four groups and goats of groups 1 and 3 were each inoculated intranasally with a 1-ml inoculum that contained 1 x 10(9) CFU/ml of live P. multocida 6:B. Following the exposure, all goats of groups 3 and 4 were injected with dexamethasone at the rate of 1 mg/kg for three consecutive days. At the end of the dexamethasone treatment, goats of groups 1 and 2 were commingled but kept separate from goats of groups 3 and 4, which were commingled in another pen. Three surviving goats from each group were killed on days 7, 14 and 21 post-exposure for postmortem examination. Naso-pharyngeal mucus and heart blood were collected on swabs. Tissues from lungs, lymph nodes and tonsils were collected for bacteriological isolation and identification. Only one goat of group 3 died 6 days post-exposure showing clinical signs and lesions typical of HS. Other goats showed mild signs of upper respiratory tract infection. Goats of all groups developed acute mild pneumonic lesions, however, those treated with dexamethasone had significantly (P < 0.05) more extensive lesion scoring based on the lesion scoring system. P. multocida 6:B was isolated from the nasal mucosa and lung lesions of exposed and contact goats not treated with dexamethasone. Exposed and contact goats treated with dexamethasone carried the organism for 21 days. P. multocida isolation from heart blood was made only from exposed and contact goats treated with dexamethasone. P. multocida was isolated from the lymph node of the goat that died during the experiment.     

The effect of Pasteurella haemolytica A2 infection on phagocytosis efficiency of caprine broncho-alveolar macrophages

An experiment was designed to study the in vivo effect of Pasteurella haemolytica A2 infection on the phagocytosis activity of caprine broncho-alveolar macrophages and the extent of pneumonic lesions. Twelve healthy local Kacang goats, about 7 months of age, were divided into two groups of six. Goats in group 1 were inoculated intratracheally with 4 ml inoculum containing 2.8 x 10(9) colony-forming units (CFU)/ml of Staphylococcus aureus. Goats in group 2 were inoculated intratracheally with 4 ml of inoculum containing 9.5 x 10(8) CFU/ml of Pasteurella haemolytica A2 isolated earlier from pneumonic lungs of goat. At intervals of 3 and 7 days post-challenge five goats from each group were killed and the lungs were washed with sterile phosphate-buffered saline. Smears were prepared from the lung washing fluid and the number of macrophages with phagocytic activity was determined. At day 3 post-infection, goats of both groups showed a similar pattern of pneumonic lesion. The lung washing fluid of goats in group 2 was found to contain numerous neutrophils and macrophages. Goats in group 2 showed significantly (P < 0.05) higher extent of lung lesions than group 1. Similarly, the average extent of lung lesions was significantly (P < 0.05) more severe in group 2 at day 7 post-infection. The lung washing fluid contained mostly macrophages. The phagocytic activity following S. aureus infection was more efficient and significantly (P < 0.01) higher compared with infection by P. haemolytica A2. There were weak correlations between the extent of pneumonic lesion and the phagocytic activity. Thus, goats with poor phagocytic activity were likely to develop more extensive lung lesions.     

Fenbendazole for treatment of Paragonimus kellicotti infection in dogs.

The effect of fenbendazole therapy was studied in 9 dogs with pulmonary paragonimiasis induced by inoculation of metacercariae (25/dog) of Paragonimus kellicotti. At 42 to 47 days after 6 dogs were inoculated, they were given fenbendazole in 2 divided doses totaling 50 mg (4 dogs) or 100 mg (2 dogs)/kg of body weight each day for 10 to 14 days. Three dogs were not treated. The passage of Paragonimus eggs in the feces ceased after 3 days at the high dosage and after 3 to 8 days at the low dosage. All dogs were euthanatized and necropsied on day 14. Live flukes were not recovered from the lungs of any treated dog, but 15, 19, and 23 live flukes were recovered from the untreated dogs.     

Effect of danofloxacin (Advocin A180) on goats affected with contagious caprine pleuropneumonia

The efficacy of danofloxacin (Advocin A180) was evaluated for the treatment of contagious caprine pleuropneumonia (CCPP) caused by Mycoplasma capricolum subsp. capripneumoniae. Ten healthy Angora goats, confirmed free of CCPP, were exposed to clinically affected animals from a natural outbreak in Thrace, Turkey. After 14 days exposure, 8 goats showed pyrexia ( > or = 41 degrees C). Shortly after, the Angora goats were divided randomly into two groups. Five of these were injected with danofloxacin (6 mg/kg subcutaneously), which was repeated after 48 h; the five remaining animals received saline. Goats were monitored clinically and blood samples were collected for serology. Animals with severe disease were withdrawn from the trial. Goats completing the study were euthanized at day 42. Lung tissue and bronchial fluid were collected for mycoplasma isolation. All danofloxacin-treated goats showed resolution of clinical disease by the end of the trial. Two saline-treated goats failed to complete the study owing to CCPP. Danofloxacin-treated goats showed fewer lung lesions and had significantly lower combined clinical scores than saline controls (p < 0.001). Danofloxacin was found to be highly effective in the treatment of CCPP in goats.     

Efficacy of ivermectin in injectable and oral paste formulations against eight-week-old Strongylus vulgaris larvae in ponies

A controlled test method was used to evaluate the efficacy of injectable micelle and oral paste formulations of ivermectin (22,23-dihydroavermectin B1) against 8-week-old Strongylus vulgaris larvae in experimentally infected pony foals. The dosage level of the drug in both formulations tested was 0.2 mg/kg. Ponies were euthanatized and necropsied 5 weeks after treatment. Based on the recovery of live vs dead S vulgaris from mesenteric arteries, both formulations were greater than 99% effective. Increased weight gains and marked reductions in the severity of arterial lesions were observed in treated ponies.     

Protective effect following intranasal exposure of goats to live Pasteurella multocida B:2

This study aimed to determine the effect of intranasal exposure to low doses of Pasteurella multocida B:2 on survival of goats challenged with high doses of the same organism. Eighteen goats were selected and divided into three groups. Goats of group 1 were exposed intranasally twice, with a two-week interval, to 7× 10⁶ cfu/ml of live P. multocida B:2. Goats of group 2 were not exposed to P. multocida B:2 but were kept together with the exposed group 1. Goats of group 3 remained as unexposed controls and were kept separated from the other two groups. Serum samples were collected at weekly intervals to determine the antibody levels. At week 5 post exposure, all goats were challenged subcutaneously with 3.7× 10¹⁰ cfu/ml of live P. multocida B:2. Following challenge exposure, 8 (67%) goats (4 goats from each of groups 1 and 2) were killed owing to haemorrhagic septicaemia. Four goats were killed peracutely within 48 h post challenge, while the other four goats were killed acutely between 2 and 4 days post challenge. None of the goats of group 3 were killed for haemorrhagic septicaemia. Goats of groups 1 and 2 showed significantly (p<0.05) higher antibody levels following the first intranasal exposure to P. multocida B:2. However, only group 1 retained the significantly (p<0.05) high antibody levels following a second intranasal exposure, and remained significantly (p<0.05) higher than groups 2 and 3 at the time of challenge. P. multocida B:2 was successfully isolated from various organs of goats that were killed between 1 and 4 days post challenge.     

Use of febantel or ivermectin for treatment of calves with experimentally induced Bunostomum phlebotomum infection

In the first of 2 separate trials, the efficacy of febantel, given at a dosage of 5 mg/kg of body weight, was assessed in calves with 60-day experimentally induced Bunostomum phlebotomum infection. Ten calves were given febantel paste, and 10 were given the vehicle only. All 20 calves were necropsied 7 days after cessation of treatment. Compared with untreated calves, febantel-treated calves harbored 99.4% fewer nematodes. In the second trial, the efficacy of ivermectin, given as a paste formulation at a dosage of 0.2 mg/kg, was assessed in calves with experimentally induced B phlebotomum infection. Ivermectin was given at 18 (n = 6) and 60 (n = 6) days after infection. At each treatment date, 3 additional calves were given vehicle only. At 67 days after infection, all calves were euthanatized. Efficacies of ivermectin against 18- and 60-day infections were 100 and 99.8%, respectively. Both anthelmintic preparations were easily administered, and adverse reactions were not observed.     

Efficacy of morantel sustained-release bolus in control of gastrointestinal nematodes of weaned calves during the autumn-winter grazing season

A 168-day study was conducted to evaluate the efficacy of morantel tartrate sustained-release bolus (MSRB) in controlling gastrointestinal parasitism in weaned calves during autumn-winter grazing in the temperature climate of southern United States. Sixty-two weanling Angus heifers were used to assess treatment differences. Six sentinel heifers were necropsied to assess pretrial gastrointestinal worm counts. The remaining 56 heifers were assigned to 4 groups of 14 heifers each and were placed on four 4.86-hectare dormant Bermuda grass pastures (1 group/pasture) that had been no-till interseeded with cereal rye in early October. Heifers in 2 groups were given 1 MSRB in early November; the other 2 groups served as nonmedicated controls. Three heifers (principals) from each of the 4 groups were necropsied on posttreatment days 57, 112, and 168 (end of study) for total worm recovery. Eight 5-month-old tracer steers, raised worm-free from birth, grazed the 4 pastures (2/pastures) for the first 21 days of the study and then were kept in drylot for 21 days before being necropsied. Level of larval contamination of pastures grazed by control and MSRB-treated heifers were comparable, because the mean number of nematodes recovered from tracer steers grazing the control and MSRB pastures were 47,449 and 53,835, respectively. At 28 days after treatment, MSRB-treated heifers had lower (P less than 0.05) mean egg counts/g of feces than did control heifers (280 vs 13).(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficacy of ivermectin against Dirofilaria immitis larvae in dogs 30 and 45 days after induced infection

Forty-two Beagles, 14 to 15 weeks of age, were injected subcutaneously with 50 infective larvae of Dirofilaria immitis and were allotted by weight, within sex, to 6 treatment groups. Group 1 served as nonmedicated vehicle-treated controls; groups 2 through 5 were given an oral tablet form of ivermectin at dosages of 0.3 micrograms/kg, 1.0 micrograms/kg, 2.0 micrograms/kg, and 3.3 micrograms/kg at 30 days after inoculation; group 6 was given the 2.0 micrograms/kg dosage at 45 days after inoculation. Dogs were euthanatized and necropsied 154 days after treatment (day 139 for dogs in group 6) and examined for heartworms. On the numerical bases of helminths recovered in the groups, the efficacies for preventing heartworm maturation were 0% (group 2), 53.2% (group 3), 97.2% (group 4), 98.1% (group 5), and 63.8% (group 6). Drug-related adverse reactions were not detected.     

Evaluation of transcutaneous pulmonoscopy for examination and biopsy of the lungs of ball pythons and determination of preferred biopsy specimen handling and fixation procedures

OBJECTIVE: To establish a safe and effective technique for the endoscopic examination and biopsy of snake lungs by use of a 2.7-mm rigid endoscope system. DESIGN: Clinical trial. ANIMALS: 17 adult ball pythons (Python regius). PROCEDURES: The right lung of each anesthetized snake was transcutaneously penetrated at a predetermined site. Endoscopic lung examination was objectively scored, and 3 lung biopsies were performed. Tissue samples were evaluated histologically for diagnostic quality. One year later, 11 of the 17 snakes again underwent pulmonoscopy and biopsy; specimens were placed in various fixatives to compare preservation quality. All 17 snakes were euthanatized and necropsied. RESULTS: No major anesthetic, surgical, or biopsy-associated complications were detected in any snake. In 16 of 17 pythons, ease of right lung entry was satisfactory to excellent, and views of the distal portion of the trachea; primary bronchus; intrapulmonary bronchus; cranial lung lobe; and faveolar, semisaccular, and saccular lung regions were considered excellent. In 1 snake, mild hemorrhage caused minor procedural difficulties. After 1 year, pulmonoscopy revealed healing of the previous transcutaneous lung entry and biopsy sites. Important procedure-induced abnormalities were not detected at necropsy. Diagnostic quality of specimens that were shaken from biopsy forceps into physiologic saline (0.9% NaCl) solution before fixation in 2% glutaraldehyde or neutral-buffered 10% formalin was considered good to excellent. CONCLUSIONS AND CLINICAL RELEVANCE: By use of a 2.7-mm rigid endoscope, lung examination and biopsy can be performed safely, swiftly, and with ease in ball pythons. Biopsy specimens obtained during this procedure are suitable for histologic examination.