A national survey of the clinical features, treatment and importance of infectious bovine keratoconjunctivitis

Perceptions and practices of Australian cattle farmers for the treatment of pinkeye (infectious bovine keratoconjunctivitis)

Pinkeye or infectious bovine keratoconjunctivitis is a globally significant disease and occurs in every state of Australia. Economic loss due to pinkeye can be considerable and it is a major welfare concern, but not all cattle with the disease are treated by farmers. This study was conducted to understand the perceptions and practices of Australian farmers regarding the treatment of pinkeye: factors influencing when farmers treat pinkeye, treatments used and considered effective, and reasons for not treating. Data were gathered using a custom designed online questionnaire. Farmer responses suitable for assessment (n = 985) were analysed using descriptive analyses along with univariable and multivariable ordinal logistic regression models to evaluate the association of 15 explanatory variables with the outcome "when do you treat pinkeye?". Results revealed three variables, farm size, times yarded and ranking of the pain caused by pinkeye, were significantly associated with the frequency of pinkeye treatment. Specifically, farmers with smaller farm sizes were more likely to treat their cattle for pinkeye more frequently. So too were those who yarded their cattle more, and those that rated pinkeye as highly painful. The most used treatments for pinkeye in Australia were pinkeye ointments (n = 861), followed by eye patches (n = 637), pinkeye spray (n = 623), fly control (n = 507), and pinkeye powder (n = 408). Over half of those who had used subconjunctival injection, pinkeye ointments, eye patches, injectable antibiotics and veterinarians rated them as highly effective treatments. Kerosene is still used by some farmers (n = 106). The most common reason for not treating pinkeye was that it was 'too difficult to treat individuals'. These findings provide insight into the attitudes of Australian farmers to the treatment of pinkeye and should be used to improve pinkeye outcomes in cattle.

Risk factors associated with pinkeye in Australian cattle

Pinkeye is the most important bovine ocular disease worldwide and a major welfare and economic concern to the Australian cattle industry. Pinkeye can occur in epidemic proportions, but severity and susceptibility vary within and between herds, indicating that the disease is multifactorial. This study was conducted to identify the on-farm risk factors associated with pinkeye disease in Australian cattle. Data were gathered from cattle farmers using a custom designed online questionnaire. Farmer responses suitable for assessment (n = 999) were analysed with descriptive, univariable and multivariable logistic regression to evaluate the association of 26 explanatory variables with pinkeye within-herd prevalence. Results revealed that farm location, farm grazing area, farmer-reported dust levels, fly levels, rain levels, animal zebu content and cattle age were significantly associated with pinkeye prevalence. More specifically, having a farm located in southern Australia, of smaller grazing area with cattle ≤ 2 years of age, was associated with a higher pinkeye prevalence. Pinkeye prevalence was also greater if respondents ranked their farms as having high fly levels compared to moderate and low fly levels, respectively and on farms ranked low for rainfall compared to moderate and high rainfall, respectively. Those that ranked their farms as having high dust levels had more pinkeye compared to moderate and low dust levels, but moderate dust levels were protective compared to low dust levels. The results confirm that pinkeye disease is multifactorial and is associated with a range of host and environmental factors. These findings should be used to assist in the control of the disease and improve pinkeye outcomes in Australian cattle.

A Review of Global Prevalence and Economic Impacts of Infectious Bovine Keratoconjunctivitis

A summary of available literature on the prevalence and estimated economic impacts of infectious bovine keratoconjunctivitis (IBK) from around the world is made. Country-level prevalence of IBK has been reported only for the United States, Australia, and New Zealand. We provide an estimate of IBK prevalence rate by geographic climate and region accounting for cattle sub-species and age. Estimated prevalence worldwide is 2.78%. Historical economic impact assessments are available only for the United States, Australia, and United Kingdom. Rarely do assessments capture the full economic cost of the disease. Better data on prevalence and how treatment and prevention decisions modify disease impacts is required to estimate the global economic impact.

The epizootic situation of cattle moraxellosis in several economic entities of the Republic of Kazakhstan

BACKGROUND AND AIM

Infectious bovine keratoconjunctivitis (IBK; conjunctivitis) is a widespread eye disease in cattle. In 1960, the Gram-negative bacillus Moraxella bovis was discovered as one of IBK's etiological causal agents. This study aimed to clarify the epidemiological (epizootic) situation of cattle moraxellosis in the Republic of Kazakhstan. The study also maps the quantitative and qualitative indicators of the epidemiological (epizootic) process to develop more effective antiepizootic measures.

MATERIALS AND METHODS

We clinically examined both imported and local cattle species based on existing epidemiological (epizootological) units of economic entities in Kazakhstan. Then, we selected biomaterials for laboratory tests to screen for moraxellosis.

RESULTS

We clarified the epizootic situation for moraxellosis of cattle in Kazakhstan using data from the Meat Union of Kazakhstan, veterinary reports from the Veterinary Control and Surveillance Committee of the Ministry of Agriculture, Kazakhstan, and our results, obtained during visits to farms in the various regions of the republic.

CONCLUSION

Based on the data of the conducted studies, we developed epizootic visualization maps with quantitative indicators of the cattle moraxellosis epizootic-transfer processes within various regions of Kazakhstan for 2019. The data obtained from studies of the properties of the isolated cultures compared with the characteristics of reference strains gave grounds to classify them as belonging to the Moraxella genus.

Current incidence, treatment costs and seasonality of pinkeye in Australian cattle estimated from sales of three popular medications

Pinkeye is an economically important ocular disease occurring in all cattle producing areas of Australia. This study was undertaken to estimate the frequency of occurrence of the disease in Australia and treatment costs of the disease to the cattle industry using the sales of popular pinkeye medications as a surrogate indicator. Monthly sales data for Orbenin® Eye Ointment, Opticlox® Eye Ointment and Terramycin® Pinkeye Aerosol were analysed. We first estimated the number of cattle that can be treated with a syringe or a can and then using the data of sales of these pinkeye medications and the total cattle population of Australia, estimated the incidence of pinkeye. Probability distributions were used to include uncertainty around the estimates. Costs to producers were estimated based on retail prices of these medications. The results indicated that 732,864 syringes of Orbenin® Eye Ointment, 134,800 syringes of Opticlox® Eye Ointment and 27,755 cans of Terramycin® Pinkeye Aerosol are sold in Australia per year. Based on some assumptions of the number of cases treated by these drugs and number of cases left untreated, the number of cattle affected by pinkeye each year in Australia was estimated to be 2.80 million (95 % PI: 1.76, 4.65) or 10.25 % (95 % PI: 6.43, 16.97) of the entire Australian cattle herd. The cattle industry is expected to lose AU$ 9.67 million (95 % PI: 8.56, 13.11) each year just considering the cost of these three drugs. The results suggest that losses due to pinkeye in the Australian cattle industry are considerably higher than previously thought and should be used to inform the development of disease prevention and control policies.

Randomised Control Trial Comparing Cypermethrin-Based Preparations in the Prevention of Infectious Bovine Keratoconjunctivitis in Cattle

Simple Summary

Infectious bovine keratoconjunctivitis (IBK) caused by the bacteria Moraxella bovis is commonly seen in the summer months spread by face flies causing a painful eye disease. This trial investigated the difference in number of cases of IBK between two groups of animals that were treated with two different fly control products, one a pour-on and one an impregnated ear tag. The growth rate per day was also investigated between animals with cases and those without and between the treatment groups. The trial enrolled 197 animals. Cases of IBK and growth rate were recorded over the grazing season (April–November 2018). Fifty-four cases of IBK were recorded. There was no difference in number of cases between the two treatment groups and there was no difference in growth rate between animals that had a case and animals that had not. Animals that had white faces, which in this trial were Hereford cattle and also the animals under 12 months old were found to be more likely to get a case. Overall, there was no significant difference between the two fly control preparations in preventing IBK, younger animals and white-faced breeds are significantly more likely to suffer from IBK.

Abstract

Infectious bovine keratoconjunctivitis (IBK) caused by Moraxella bovis is commonly seen in the summer months spread by face flies. This trial investigated the difference in incidence of IBK cases from natural exposure between two groups of animals, one treated with Cypermethrin pour-on preparation (PON, n = 98) and one with Cypermethrin impregnated ear tags (TAG, n = 99). Daily Live Weight Gain (DLWG) difference was investigated between animals with cases and those without and between treatment groups. A randomised positive control study, enrolled 197 animals split into two treatment groups. Cases of IBK and DLWG were recorded over the grazing season (April–November 2018). Fifty-four cases of IBK were recorded. There was no association between the two treatment groups (p = 0.362) and case status. Breed and under 12 months old were significant factors for having a case; (OR 2.3, p = 0.014 and OR 3.5, p < 0.001 respectively). There was no difference in DLWG between animals that had a case and animals that had not (p = 0.739) or between the two treatment groups (p = 0.215). Based on our results, there is no significant difference between PON or TAG preparations in the prevention of IBK. Younger animals and white-faced breeds are significantly more likely to suffer with IBK.

Moraxella bovoculi em casos de ceratoconjuntivite infecciosa bovina no Rio Grande do Sul

A ceratoconjuntivite infecciosa (CI), embora raramente fatal, resulta em perdas econômicas significativas para os rebanhos bovinos e ovinos. Os principais agentes causadores dessa enfermidade são Moraxella bovis e Moraxella ovis. Em 2007 foi descrita uma nova espécie também responsável pela CI e denominada Moraxella bovoculi, que até o presente momento, não havia sido relatada no Brasil. Assim, objetivou-se com este trabalho caracterizar e distinguir 54 isolados de Moraxella spp. de amostras clínicas oriundas de 34 bovinos e 17 ovinos, encaminhadas ao Laboratório de Bacteriologia da Universidade Federal de Santa Maria no período de 1990 a 2011, visando a identificação de M. bovoculi. A distinção dos isolados foi fundamentada nas características genotípicas, pela amplificação parcial da região intergênica 16S-23S e clivagem dos produtos da amplificação com enzima RsaI. Como resultados, 25 (46%) isolados foram caracterizados como M. bovis, 17 (32%) como M. ovis e 12 (22%) como M. bovoculi. Logo, conclui-se que M. bovoculi encontra-se presente no rebanho bovino do Rio Grande do Sul e, portanto, no Brasil.

Genetic parameters of infectious bovine keratoconjunctivitis and its relationship with weight and parasite infestations in Australian tropical Bos taurus cattle

Background

Infectious bovine keratoconjunctivitis (IBK) or ‘pinkeye’ is an economically important ocular disease that significantly impacts animal performance. Genetic parameters for IBK infection and its genetic and phenotypic correlations with cattle tick counts, number of helminth (unspecified species) eggs per gram of faeces and growth traits in Australian tropically adapted Bos taurus cattle were estimated.

Methods

Animals were clinically examined for the presence of IBK infection before and after weaning when the calves were 3 to 6 months and 15 to 18 months old, respectively and were also recorded for tick counts, helminth eggs counts as an indicator of intestinal parasites and live weights at several ages including 18 months.

Results

Negative genetic correlations were estimated between IBK incidence and weight traits for animals in pre-weaning and post-weaning datasets. Genetic correlations among weight measurements were positive, with moderate to high values. Genetic correlations of IBK incidence with tick counts were positive for the pre-weaning and negative for the post-weaning datasets but negative with helminth eggs counts for the pre-weaning dataset and slightly positive for the post-weaning dataset. Genetic correlations between tick and helminth eggs counts were moderate and positive for both datasets. Phenotypic correlations of IBK incidence with helminth eggs per gram of faeces were moderate and positive for both datasets, but were close to zero for both datasets with tick counts.

Conclusions

Our results suggest that genetic selection against IBK incidence in tropical cattle is feasible and that calves genetically prone to acquire IBK infection could also be genetically prone to have a slower growth. The positive genetic correlations among weight traits and between tick and helminth eggs counts suggest that they are controlled by common genes (with pleiotropic effects). Genetic correlations between IBK incidence and tick and helminth egg counts were moderate and opposite between pre-weaning and post-weaning datasets, suggesting that the environmental and (or) maternal effects differ between these two growth phases. This preliminary study provides estimated genetic parameters for IBK incidence, which could be used to design selection and breeding programs for tropical adaptation in beef cattle.

Examination techniques and therapeutic regimens for the ruminant and camelid eye

A step-wise procedure and necessary equipment for examination of the ruminant and camelid eye are detailed. Restraint techniques and usage of local anesthetics to facilitate examination are described. Common examination findings and their significance are discussed. Finally, therapeutic options for keratoconjunctivitis and uveitis are explored. A complete ocular examination of ruminants is often not performed in the field because of lack of time, lack of appropriate facilities, and/or lack of equipment. Although individual ophthalmic examinations are not frequently performed as part of a herd health program, they can be of value in select cases. Ocular manifestations of systemic diseases may assist the clinician in establishing a diagnosis on the farm and for little additional cost. For patients with a specific ocular complaint, a complete ophthalmic examination is critical. After completion of the examination and arrival at a diagnosis, one must also be cognizant of the therapeutic regimens that are appropriate for use in ruminants, particularly animals that may be used for meat or milk.

Isolation of Moraxella bovis from frozen bovine semen and determination of microbial load

In the present study, isolation of Moraxella bovis was done from the microbiological examination of frozen semen straws from clinically healthy twelve Jersey and one Jersey-cross bull supplied by a semen laboratory. The organism was identified on the basis of colonial morphology and biochemical characteristics. Further, viable cell count of the bacterium was studied in detail in the semen sample.

Infectious bovine keratoconjunctivitis antimicrobial therapy

Infectious bovine keratoconjunctivitis (IBK) is one of the most common diseases of cattle and is of major economic importance. If the primary aetiological agent, Moraxella bovis, is successfully eliminated from ocular tissues corneal ulcers heal at a constant rate. If treatment is unsuccessful ulcer reoccurrence may follow initial healing. Appropriate antimicrobial selection requires knowledge of antimicrobial sensitivities and distribution in ocular tissues and tears. Drugs may be delivered to the eye in several ways: subconjunctival injection, topical application and systemic administration. While therapeutic efficacy is affected by the frequency and mode of drug delivery, variations between intensive and extensive enterprises dictate the practical method of antimicrobial delivery. Specific recommendations for antimicrobial therapies targeting Australian IBK outbreaks are dependent upon antimicrobial pharmacokinetics, drug regulations and associated costs.

Identification of a capsular polysaccharide from Moraxella bovis

The bacterium Moraxella bovis is the causative agent of an economically important disease of cattle: Infectious Bovine Keratoconjunctivitis (IBK), otherwise known as pinkeye. Little is known regarding the structure of the carbohydrates produced by M. bovis. The structure of a capsular polysaccharide from M. bovis (strain Mb25) has been determined using NMR and MS analysis. From these data it is concluded that the polysaccharide is composed of the unmodified chondroitin disaccharide repeat unit.

Evaluation of lysozyme and lactoferrin in lacrimal and other ocular glands of bison and cattle and in tears of bison

OBJECTIVE

To evaluate lactoferrin and lysozyme content in various ocular glands of bison and cattle and in tears of bison.

SAMPLE POPULATION

Tissues of ocular glands obtained from 15 bison and 15 cattle and tears collected from 38 bison.

PROCEDURE

Immunohistochemical analysis was used to detect lysozyme and lactoferrin in formalin-fixed, paraffin-embedded sections of the ocular glands. Protein gel electrophoresis was used to analyze ocular glands and pooled bison tears by use of a tris-glycine gel and SDS-PAGE. Western blotting was used to detect lactoferrin and lysozyme.

RESULTS

Immunohistochemical staining for lactoferrin was evident in the lacrimal gland and gland of the third eyelid in cattle and bison and the deep gland of the third eyelid (Harder's gland) in cattle. Equivocal staining for lactoferrin was seen for the Harder's gland in bison. An 80-kd band (lactoferrin) was detected via electrophoresis and western blots in the lacrimal gland and gland of the third eyelid in cattle and bison, Harder's glands of cattle, and bison tears. An inconsistent band was seen in Harder's glands of bison. Lysozyme was not detected in the lacrimal gland of cattle or bison with the use of immunohistochemical analysis or western blots. Western blots of bison tears did not reveal lysozyme.

CONCLUSIONS AND CLINICAL RELEVANCE

Distribution of lactoferrin and a lack of lysozyme are similar in the lacrimal gland of cattle and bison. Differences in other tear components may be responsible for variability in the susceptibility to infectious corneal diseases that exists between bison and cattle.

Characterization of hemolysin of Moraxella bovis using a hemolysis-neutralizing monoclonal antibody

A concentrated bacterial culture supernatant from the hemolytic Moraxella bovis strain UQV 148NF was used to immunize mice and generate monoclonal antibodies (MAbs). One, MAb G3/D7, neutralized the hemolytic activity of M. bovis and recognized a 94-kDa protein by Western blot analysis in hemolytic M. bovis strains representing each of the different fimbrial serogroups. Exposure of corneal epithelial cells to M. bovis concentrated culture supernatants demonstrated a role for an exotoxin in the pathogenesis of infectious bovine keratoconjunctivitis, while neutralization of hemolytic and cytotoxic activities by MAb G3/D7 implies that these activities are related or have common epitopes. The action of M. bovis hemolysin was further characterized in sheep erythrocyte preparations with a binding step and Ca(2+) required for lysis to proceed, similar to the RTX family of bacterial exotoxins. Neutralization of lytic activity in vitro is evidence for the presence of M. bovis antigens, which may be capable of protecting cattle from the development of infectious bovine keratoconjunctivitis.

Infectious bovine keratoconjunctivitis: a review

The economic impact of infectious bovine keratoconjunctivitis (IBK) warrants continued investigation of the mechanisms by which Moraxella bovis survives on and colonizes the corneal surface. Virulent strains of M bovis produce hemolysin and exhibit different plasmid profiles than nonvirulent strains. Interactions among host, environment, vector, season, and concurrent infection influence the prevalence of IBK. Mycoplasma sp. or infectious bovine rhinotracheitis virus may enhance or hasten the disease process. The manifestations of IBK may range from mild conjunctivitis to severe ulceration, corneal perforation, and blindness. Treatment of IBK is dictated by economic considerations, intended animal use, and feasibility of administration. Antibiotic therapy is aimed at achieving drug concentrations in tears to meet or exceed the minimum inhibitory concentration for prolonged periods. At present, IBK is not a preventable disease. Affected animals must be separated from the herd and vector control vigorously instituted. Carrier animals must be identified and removed from the herd. Vaccination trials have been unsuccessful because of pili antigen cross-reactivity, variable strains, and uncontrolled environmental factors. Recent investigations have determined that M bovis may utilize host iron sources via iron-repressible outer membrane proteins and siderophores for growth. Elucidation of normal defense mechanisms of the bovine eye may lead to new strategies to enhance the immune response against M bovis.

Ocular drug delivery in veterinary medicine

This paper provides a comprehensive overview of the various approaches currently used in the development of ocular drug delivery systems for the treatment of ocular diseases in animals. It is obvious from the literature that most of the products that are currently available are derived from human medicine without consideration given to the differences which exist between the anatomy and physiology of the eye of various animal species which ultimately affect product design and performance. As a result, many of the products for animal use seem in many circumstances inappropriate for animal care. The article deals with some aspects of eye anatomy and physiology of different animals, and then provides an overview of the most commonly encountered pathologies. The paper then discusses the currently available drug products and finally reviews new delivery concepts. Several hundred references are included in the paper and provide access to further information on the subject.

A haemolytic cell-free preparation of Moraxella bovis confers protection against infectious bovine keratoconjunctivitis

Protection conferred by a cell-free preparation from a haemolytic Moraxella bovis isolate, UQV 148NF, was compared to an equivalent fraction from a non-haemolytic M. bovis isolate, Gordon 26L3, and to a recombinant DNA-derived pili vaccine. Three groups of ten calves were vaccinated twice with one of the three preparations and, together with ten non-vaccinated calves, challenged with virulent M. bovis isolate Dal 2d. Compared to the control group, significant protection was observed in the group receiving the pili vaccine and the group receiving the preparation from haemolytic isolate, UQV 148NF.

Characterisation of the outer membrane protein antigens of British field isolates of Moraxella bovis

Outer membranes of a single isolate of Moraxella bovis were prepared and their purity evaluated by a comparison of the iodinated proteins from whole cells and on outer membranes. The protein patterns of the outer membranes of 10 isolates were examined by SDS-polyacrylamide gel electrophoresis, and the antigenic relationship between proteins of different isolates determined by immunoblotting, using antiserum produced against the outer membrane of the single isolate of M. bovis. The overall protein pattern of the different isolates was similar although not identical, but, significantly, only three separate immunogenic proteins were common to all the isolates under examination.

A survey of infectious bovine keratoconjunctivitis in the Gisborne and Hunterville regions of New Zealand

A postal survey of 400 beef farmers in the Hunterville and Gisborne districts sought to identify features of farms or management procedures that might influence the occurrence, transmission or severity of infectious bovine keratoconjunctivitis (IBK). The overall response rate was 72%. The annual incidence of IBK outbreaks rose from 10% to 28% between the years 1977 to 1981 and was similar for both districts. Prevalence was highest during mid-summer and lowest in mid-winter. Larger properties were more prone to outbreaks. In both districts, farmers of IBK-free properties purchased fewer cattle than those who had experienced IBK and this distinction was more evident in the Hunterville area. Only in the Gisborne district did a Hereford breed predisposition to infection become apparent. All age groups were affected with IBK but the attack rate was highest in the younger cattle. Eleven percent of farmers routinely treated their cattle for IBK and that produced an earlier resolution of lesions and fewer cattle in which healing extended longer than four weeks. Most farmers considered IBK to be an inconvenience which limited livestock production through reducing growth rates and lowering monetary returns when stock had to be sold at unsuitable times. Eye disfigurement caused loss of value in stud and export stock.

Ocular inserts for application of drugs to bovine eyes--in vitro studies on gentamicin release from collagen inserts

Soluble collagen and insoluble collagen films were impregnated with gentamicin and investigated in vitro as vehicles for the delivery drugs. Succinylated collagen released significantly higher levels of antibiotic than the insoluble films, and maintained mean inhibitory concentrations (MIC) for Moraxella bovis for 24 h.

A national survey of the clinical features, treatment and importance of infectious bovine keratoconjunctivitis

A postal survey of cattle producers throughout Australia was conducted to obtain information concerning the occurrence, signs and treatment of infectious bovine keratocojunctivitis, animals breeds, animal numbers and types, environmental conditions under which the animals were kept and management routines and systems of the animals (Slatter et al 1982). The most common clinical signs reported were ocular discharge (43.9%), corneal opacity (9.9%), or both (46.1%). The majority of respondents (54.8%) indicated duration of infections of at least 3 weeks. The condition was predominantly unilateral (74.7%) but 22.3% of respondents reported an equal occurrence of the condition unilaterally and bilaterally. The most frequently used drugs were homidium bromide (26.7%), oxytetracycline hydrochloride (22.8%), chloramphenicol derivatives (13.7%) and penicillin derivatives (13.5%). However, described treatment regimes indicated that therapeutic levels of antibiotics would not be maintained in the eyes of treated animals. Producers considered that 75% of affected animals showed reduced rates of weight gain, and 64% indicated they were more difficult to handle. An approximate figure of +22,000,000 was determined for loss of national production due to the disease, based on producers' estimates. In addition, a further cost of +1,566,500 was estimated for the labour involved in current treatment regimes. Beef and dairy producers spent different amounts on medications and treated for different durations. The economic significance of the disease justifies further studies on production losses due to the disease and cost effective methods of treatment.