The livestock industry has been relying merely on chemically synthesised antibiotic for eye infections as sprays and ointment. A natural remedy from Curcuma spp. has been tested for efficacy in curing keratoconjunctivitis and uveitis. A severe case of uveitis was cured within 7 days, with impaired vision restored. These results were observations of a preliminary study conducted in a goat with uveitis.

Objective: To measure florfenicol concentrations in ovine tear fluid after IM and SC administration and determine minimum inhibitory concentrations (MICs) of florfenicol against field isolates of Mycoplasma organisms potentially involved in infectious keratoconjunctivitis. Animals: 9 healthy adult Lacaune ewes. Procedures: Animals received an IM and SC administration of florfenicol (20 mg/kg) in a 2-way crossover design. Samples of blood and tear fluid were collected before and for 24 hours after administration. Concentrations of florfenicol in plasma and tear fluid were measured via high-performance liquid chromatography. The MIC of florfenicol for various Mycoplasma strains cultured from sheep and goats was determined via an agar dilution method. Results: Mean florfenicol concentration in tear fluid for the 24-hour period was significantly higher after IM administration (0.70 μg/mL) than after SC administration (0.22 μg/mL) and was maintained for a longer duration. The lacrimal fluid-to-plasma concentration ratio was not different between the 2 routes of administration, with mean values of 40.2% and 32.5% after IM and SC administration, respectively. The MIC for Mycoplasma agalactiae, Mycoplasma conjunctivae, and Mycoplasma mycoides isolates ranged from 0.5 to 8 μg of florfenicol/mL. Two strains of M agalactiae could be considered resistant to florfenicol. Conclusions and Clinical Relevance: Florfenicol readily penetrated the preocular tear fluid of sheep after IM and SC administration. For both routes of administration, doses > 20 mg/kg would be necessary to achieve tear fluid concentrations of florfenicol greater than the MICs for most strains of Mycoplasma organisms.

The objective of this study was to determine the potential of Bdellovibrio bacteriovorus 109J as an alternative non-chemotherapeutic treatment of infectious bovine keratoconjunctivitis (IBK). To accomplish this, various parameters of B. bacteriovorus predation of Moraxella bovis were determined in vitro. Initial passage of B. bacteriovorus using M. bovis as prey required 10 d for active cultures to develop compared with 2 d for culture on normal Escherichia coli prey; however by the 5th passage, time to active predatory morphology was reduced to 2 d. This high passage B. bacteriovorus culture [1 × 10(10) plaque forming units (PFU)/mL] killed 76% of M. bovis [1 × 10(7) colony forming units (CFU)/mL] present in suspension broth in a 4 h assay. The minimal level of M. bovis supporting B. bacteriovorus predation was 1 × 10(4) CFU/mL. To assess the ability of B. bacteriovorus to kill M. bovis on an epithelial surface mimicking IBK, an in vitro assay with Madin-Darby bovine kidney (MDBK) cells inoculated with 4 × 10(7) CFU/mL M. bovis was used. Treatment with a B. bacteriovorus suspension (1.6 × 10(11) PFU/mL) decreased adherence of M. bovis to MDBK cells by 6-fold at 12 h of treatment, as well as decreased the number of unattached M. bovis cells by 1.4-fold. This study demonstrates that B. bacteriovorus has potential as an effective biological control of M. bovis at levels likely present in IBK-infected corneal epithelia and ocular secretions.

Two commercially available infectious bovine keratoconjunctivitis (IBK) vaccines were evaluated for their effectiveness in protecting cattle from disease caused by experimental challenge exposure and natural transmission of Moraxella bovis infections. The study was conducted as 2 experiments, using a total of 81 cattle that were culture-negative for M bovis prior to vaccination. In each experiment, young adult cattle were randomly allotted to 4 groups. Each calf in groups 1 and 2 was vaccinated according to the vaccine manufacturer's directions. Groups 3 and 4 were unvaccinated controls. Three weeks after the last vaccination, each calf in groups 1 and 3 was experimentally challenge exposed by dropping a suspension of viable cells of a virulent strain of M bovis directly onto the corneal surface of each eye. Calves in all 4 groups were then commingled in open pastures so that calves in groups 2 and 4 could be naturally exposed to the calves with experimentally induced infections. Each calf was examined for signs of ocular disease on a regular basis by 2 experienced clinicians who scored each eye for severity of disease on the basis of a prearranged scale. Neither clinician was aware of the vaccination or exposure status of the calf nor to which experimental group they belonged. Lacrimal secretions were collected regularly to determine the number of eyes in which the virulent organism became established. Moraxella bovis with bacterial cultural characteristics similar to those of the virulent strain placed in the eyes of groups 1 and 3 was cultured from > 83% of the eyes of calves in all groups. The incidence of clinical IBK was > 50% in each group. There was no significant difference in the ability of vaccinated calves to resist experimental or natural challenge infection. Compared with that in nonvaccinated controls, no decreased incidence or severity of clinical IBK was noticed in vaccinated calves. Though the challenge strain used was not homologous to those used to prepare the vaccine, it was no different than those that may be expected to cause disease under field conditions.

A clinical trial examining the efficacy of 2 drugs for treatment of a natural epizootic of infectious bovine keratoconjunctivitis was performed. The study was conducted in 103 grazing Hereford calves during the summer of 1985. The calves were prospectively and randomly assigned to 1 of 3 groups at the beginning of the study on June 17, and were examined 3 times weekly thereafter until the final observation on August 6. Calves in group 1 (n = 34) were not treated and were used as controls. Calves of group 2 (n = 34) with corneal ulcers were treated with a long-acting oxytetracycline formulation (OTC group). The parenteral treatment was repeated in 72 hours. Affected calves of group 3 (n = 35) were treated topically with furazolidone spray when they developed new corneal ulcers, or when existing lesions worsened during subsequent examination periods (NFZ group). Healing times of the corneal ulcers were reported in 3 ways: the combined times for ulcers present in both eyes of a calf simultaneously (method A), independent times of each ulcer on a calf (method B), and time of the first ulcer for each calf (method C). Censored healing times were examined as left censored (ulcer present at the beginning of the study), right censored (ulcer not healed at the end of the study), or uncensored (true) healing times. The effect that the treatments had on healing times were investigated by use of notched box and whisker plots, life tables, and Cox regression models. The analysis indicated that treatment of calves with either antimicrobial reduced the healing time of corneal ulcers, compared with untreated controls. Calves treated with OTC had shorter periods with ulcers present on both eyes than did NFZ-treated calves. The healing time of the first ulcer on a calf was faster when treated with either antimicrobial than when not treated, but no significant difference between periods for OTC and NFZ treatments was found. Censored healing times were consistently longer than uncensored healing times. Box and whisker plots indicated that both treatments shortened healing times more than those for controls, and OTC shortened healing times more than did NFZ for responses A and B (but not C). Life tables showed that OTC healing times were shorter than those for controls, and NFZ shorter than controls for response B and C (but not A). Cox regression model (for response A) showed a borderline significant difference between times for OTC group and controls, and no significant difference between times for NFZ group and controls.

OBJECTIVE To evaluate changes in systemic and ocular antibody responses of steers following intranasal vaccination with precipitated or partially solubilized recombinant Moraxella bovis cytotoxin (MbxA). ANIMALS 13 Angus steers with ages ranging from 318 to 389 days and weights ranging from 352 to 437 kg. PROCEDURES Steers were assigned to receive 500 μg of a precipitated (MbxA-P; n = 5) or partially solubilized (MbxA-S; 5) recombinant MbxA subunit adjuvanted with polyacrylic acid. A control group (n = 3) received the adjuvant alone. Each steer received the assigned treatment (1 mL/nostril) on days 0 and 28. Serum and tear samples were collected on days 0 (before vaccination), 14, 28, 42, and 55. Changes in MbxA-neutralizing antibody titers and MbxA-specific IgG concentrations in serum and tears and changes in MbxA-specific IgA concentrations in tears were measured. RESULTS Mean fold changes in MbxA-specific IgG concentration in serum and tears and MbxA-neutralizing antibody titer in tears for the MbxA-P group were significantly greater than those for the MbxA-S and control groups. Mean serum MbxA-neutralizing antibody titer did not differ among the 3 groups. Although the mean fold change in tear MbxA-specific IgA concentration differed significantly among the groups in the overall analysis, post hoc comparisons failed to identify any significant pairwise differences. CONCLUSIONS AND CLINICAL RELEVANCE Systemic and ocular immune responses induced by intranasal administration of the MbxA-P vaccine were superior to those induced by the MbxA-S vaccine. Additional research is necessary to determine whether the MbxA-P vaccine can prevent naturally occurring infectious bovine keratoconjunctivitis.

Objective: To determine whether 14-day topical ocular administration of high doses of feline recombinant interferon omega (FelFN) or human recombinant interferon alpha-2b (HulFN) solution improves clinical disease and decreases virus shedding in cats with naturally acquired viral keratoconjunctivitis. Animals: 36 cats with upper respiratory tract disease and ocular involvement. Procedures: Cats received 1 drop of FelFN solution (1 × 10(6) U/mL), HulFN solution (1 × 10(6) U/mL), or saline (0.9% NaCl) solution (12 cats/group) in each eye twice daily for 14 days (beginning day 1). Oropharyngeal and conjunctival swab samples were collected from each cat before (day 0) and on day 14 of treatment for virus isolation (VI) and real-time quantitative PCR (RT-qPCR) testing to detect feline herpesvirus-1 and feline calicivirus. Subjective clinical scores were recorded on days 0, 3, 7, 10, and 14. Results: The number of cats for which feline herpesvirus-1 was detected via VI or RT-qPCR assay was generally (albeit not always significantly) lower on day 14, compared with day 0 findings; however, findings on days 0 or 14 did not differ among groups. The number of cats for which feline calicivirus was detected via VI or RT-qPCR assay did not differ significantly between days 0 and 14 for any group. Clinical scores significantly decreased over the 14-day period but did not differ among groups. Conclusions and Clinical Relevance: In cats with naturally occurring viral keratoconjunctivitis, bilateral ocular administration of high doses of FelFN or HulFN twice daily for 14 days did not improve clinical disease or virus shedding, compared with treatment with saline solution.

Objective: To evaluate efficacy of a recombinant Moraxella bovis pilin-cytotoxin-Moraxella bovoculi cytotoxin subunit vaccine to prevent naturally occurring infectious bovine keratoconjunctivitis (IBK). Animals: 107 beef steers. Procedures: 2 groups of calves were inoculated SC with an immunostimulating complex (ISCOM) matrix adjuvant (control group; n = 54) or a recombinant M bovis pilin-cytotoxin–M bovoculi cytotoxin subunit antigen with the ISCOM matrix adjuvant (vaccine group; 53); calves received booster injections 21 days later. Calves were examined once weekly for 16 weeks. Investigators and herd managers were not aware of the inoculum administered to each calf throughout the trial. Primary outcome of interest was the cumulative proportion of calves that developed IBK. Serum samples were obtained before inoculation (day 0) and on days 42 and 112. Serum hemolysin-neutralizing titers against native M bovis and M bovoculi cytotoxin were determined. Results: No difference was detected between groups for the cumulative proportion of calves that developed IBK at weeks 8 and 16 after inoculation. Non–IBK-affected calves in the vaccine group had a significantly higher fold change in serum hemolysin-neutralizing titer against native M bovoculi cytotoxin from day 0 to 42 compared to control calves. Conclusions and Clinical Relevance: The M bovis pilin-cytotoxin-M bovoculi cytotoxin subunit vaccine with the ISCOM matrix adjuvant was not effective at preventing naturally occurring IBK. It is likely that the incorporation of additional protective antigens in a recombinant Moraxella spp subunit vaccine will be required to yield a product that can be used for effective immunization of cattle against IBK.

Cross-reactivity indices (CRIs) of 28 isolates of Moraxella bovis recovered from outbreaks of infectious bovine keratoconjunctivitis in Argentina (A, 11 isolates), Brazil (B, 7), and Uruguay (U, 10) between 1983 and 2000 were estimated. Hyperimmune sera were produced in rabbits and antibody titres determined with each isolate. Isolates showing CRIs3 70 were placed in the same group. Group I had 13 isolates (A, 1; B, 6; U, 6); group II had 6 isolates (A, 4; U, 2); groups III, IV, and V had 2 isolates each, recovered in Argentina; group VI had 2 isolates, from Uruguay; and group VII had 1 isolate, from Brazil. The CRIs3 70 between vaccine strains and isolates recovered before and after 1990 were 58% and 42%, 50% and 50%, and 33% and 67% with vaccine strains 2419, 2358, and 2439, respectively. Isolate 273, from Uruguay, showed CRIs > 70 with 78% of the isolates and is recommended as the vaccine strain.

The efficacy of an ophthalmic ointment containing benzathine cloxacillin for treatment of infectious bovine keratoconjunctivitis was determined in 2 experiments. In the first experiment, Holstein calves (n = 6/group) were inoculated with Moraxella bovis and treated on postinoculation days 3 and 6 with either topically applied benzathine cloxacillin (250 mg/eye) or long-acting oxytetracycline formulation (20 mg/kg of body weight, IM). A third group of inoculated calves remained untreated as controls. For the second experiment, 4 groups of calves (n = 6/group) were inoculated and treated on postinoculation days 3 and 6 with 50, 125, 250, or 375 mg of benzathine cloxacillin; a fifth untreated group served as controls. Ocular specimens were obtained for microbiologic culture, and eyes were observed and assigned a clinical score daily. Eyes were photographed on alternate days. Ulcer surface area was measured, using a planimeter. In experiment 1, the week-2 ulcer surface area measurements for both groups of treated calves were smaller than those for controls. There was a greater frequency of M bovis isolation from the ocular secretions of controls than from those of benzathine cloxacillin-treated calves during postinoculation weeks 2 and 3. The number of M bovis isolations from the benzathine cloxacillin- and oxytetracycline-treated calves was not significantly different at any sample collection interval. On week 3, the scores of the benzathine cloxacillin-treated calves were smaller than those of controls. In experiment 2, calves of the 250- and 375-mg group had smaller scores than did controls. During postinoculation weeks 1 through 3, M bovis was isolated less frequently from the ocular secretions of calves of the 250- and 375-mg groups than from those of the control calves.