Mycoplasma conjunctivae in insect vectors and anatomic locations related to transmission and persistence.

Mycoplasma conjunctivae is an obligate microparasite that causes Infectious Keratoconjunctivitis (IKC) in Caprinae species. IKC is a long-recognised disease, but little attention has been paid to the mechanisms of transmission of the mycoplasma and its occurrence in locations other than the eyes. In this study, the presence of M. conjunctivae is assessed in the eyes, external ear canals (EEC), nasal cavity, and vagina of host species as well as in potential vectors, which may be involved in the transmission and persistence of infection within the host. M. conjunctivae was detected by qPCR in 7.2 % (CI 95% 4.7-11.0) of the ear swabs and 9.5 % (CI 95% 6.4-13.9) of the nasal swabs from Pyrenean chamois, Iberian ibex, domestic sheep and mouflon without statistical differences between species. Mycoplasma detection in nasal swabs was mostly associated with ocular infection (95.6%), but this was not the case for EEC (52.6%). Among the eye-positive ruminants, 27.3% were positive in ear swabs and 64.7% in nasal swabs, and the threshold cycle values of the qPCR were correlated only between eye and nasal swabs (p < 0.01; r2 = 0.56). M. conjunctivae was detected in 1.7% - 7.1 % of Musca spp. captured during an IKC outbreak in Iberian ibex and in one out of three endemic sheep flocks. The results indicate that the transmission of M. conjunctivae may occur by direct contact with eye or nasal secretions and/or indirectly through flies. The M. conjunctivae DNA detection in EEC suggests that it can colonise the auditory tract, but the significance for its persistence within the host should be further assessed.

Analysis on the treatment and prevention of epidemic conjunctivitis in 108 cases.

To explore the treatment method and preventive measures on epidemic keratoconjunctivitis. 108 patients with epidemic keratoconjunctivitis who received treatment in our hospital from January, 2015 to September, 2015.were selected. These patients were treated with interferon eye drops, Ganciclovir ophthalmic gel, and alternating eye treatment of tobramycin-dexamethasone eye drops and diclofenac sodium eye drops. Meanwhile, health education was also performed among patients, so as to promote the recovery of the disease as soon as possible and to prevent the spread of the disease Among the 108 patients, there were 101 patients recovered. 7 patients had cornea remained sub epithelial round hoary haze, including 2 patients with evident cornea remained sub epithelial round hoary haze due to the occurrence of glucocorticoid-induced intraocular pressure and the tobramycin and dexamethasone eye drops were suspend. The clinical cure rate was 91.79%. There was no pathophoresis to health patients among the 108 patients. Active treatment of epidemic keratoconjunctivitis, combined with health education and publicity could increase the clinical cure rate and control the transmit of the disease spread.

Moraxella bovis pathogenicity: an update.

Moraxella bovis is the etiologic agent of infectious bovine keratoconjunctivitis, the most important ocular disease affecting cattle worldwide. The severity of the cases varied from eyes that exhibited mild signs to severe clinical cases with profuse lacrimation, conjunctival swelling, corneal opacity, and ulceration. Although the mortality is low, there is a high morbidity and important economic loss in terms of significant reduction in production. This paper examines aspects such as the pathogenesis of the disease and the mechanisms by which this unique bacterium is able to disrupt the corneal epithelium and cause infection.

Infectious keratoconjunctivitis in bighorn sheep, Silver Bell Mountains, Arizona, USA.

An infectious keratoconjunctivitis (IKC) epizootic in bighorn sheep (Ovis canadensis) occurred in the Silver Bell Mountains, Arizona, USA, from 1 December 2003 to 31 March 2004. We used standard culture methods and polymerase chain reaction (PCR) amplification of the 16S rRNA gene to test for the causative agents of IKC and other diseases reported to be associated with bighorn sheep populations. All bighorn sheep and domestic goat test results were negative except for Mycoplasma spp. and Branhamella spp. The culture and PCR results differed. Conjunctival swabs from four of 19 IKC-affected bighorn sheep tested by culture were positive for Mycoplasma spp., whereas 22 of 22 bighorn sheep samples tested by PCR were positive for Mycoplasma spp. None of 13 domestic goats tested positive by culture for Mycoplasma spp., whereas five of 16 tested positive by PCR. Three of 16 domestic goats and seven of 24 IKC-affected bighorn sheep tested positive for Branhamella spp. by culture. Bighorn sheep began showing clinical signs of IKC between 21 and 28 days following initial detection of domestic goats in bighorn sheep habitat. The IKC epizootic lasted 122 days, and individual bighorn sheep were blind for an average of 38.4 days. Given the clear potential for disease transmission to bighorn sheep, we recommend that land managers not allow the pasturing of domestic goats near occupied bighorn sheep habitat.

Molecular epidemiology of Mycoplasma conjunctivae in Caprinae: transmission across species in natural outbreaks.

Mycoplasma conjunctivae is the etiological agent of infectious keratoconjunctivitis, a highly contagious ocular infection that affects both domestic and wild Caprinae species in the European Alps. In order to study the transmission and spread of M. conjunctivae across domestic and wild Caprinae populations, we developed a molecular method for subtyping and identifying strains of M. conjunctivae. This method is based on DNA sequence determination of a variable domain within the gene lppS, a gene that encodes an antigenic lipoprotein of M. conjunctivae. This domain of lppS shows variations among different strains but remains constant upon generations of individual strains on growth medium and thus allows identification of individual strains and estimation of their phylogenetic intercorrelations. The variable domain of lppS is amplified by PCR using primers that match conserved sequences of lppS flanking it. Sequence analysis of the amplified fragment enables fine subtyping of M. conjunctivae strains. The method is applicable both to isolated strains and to clinical samples directly without requiring the cultivation of the strain. Using this method, we show that M. conjunctivae was transmitted between domestic and wild animals that were grazing in proximate pastures. Certain animals also presented infections with two different strains simultaneously.

Infectious keratoconjunctivitis of ibex, chamois and other Caprinae.

Infectious keratoconjunctivitis (IKC) caused by Mycoplasma conjunctivae is a highly contagious ocular infection which is common in domestic sheep and goats. In the European Alps, IKC is often observed in Alpine chamois (Rupicapra r. rupicapra) and in Alpine ibex (Capra i. ibex), but the disease has also been described in other wild Caprinae in the Pyrenees and in New Zealand. The infection is characterised by inflammation of the conjunctiva and cornea, and in the most advanced stages, the cornea is opaque or even perforated. In IKC outbreaks in chamois and ibex, spontaneous recovery is the most prevalent outcome of the disease. However, mortality can occasionally reach 30%. Recent studies in eastern Switzerland indicated that M. conjunctivae infection is not self-maintained in chamois. In contrast, the disease is endemic and self-maintained in the domestic sheep population. Spillover of the agent from sheep living in proximity during summer may be the origin of point-source epidemics in wild Caprinae. Flies are likely to play a central role in interspecific transmission of M. conjunctivae on alpine meadows. When outbreaks of IKC occur in wildlife, a special effort should be made to avoid unnecessary human disturbance in affected areas. However, animals presenting irreversible ocular lesions should be shot by professional gamekeepers to prevent suffering. Prevention of IKC in wild Caprinae should focus on preventing the spillover of M. conjunctivae from livestock. However, studies are required to evaluate the distribution of M. conjunctivae infection in domestic sheep in several countries and to assess the risk of IKC spillover from domestic animals to wildlife. In addition, immunological studies should be performed to develop tools which could lead to the control of M. conjunctivae infection in domestic sheep.

Survival analysis for evaluation of corneal ulcer healing times in calves with naturally acquired infectious bovine keratoconjunctivitis.

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.(ABSTRACT TRUNCATED AT 250 WORDS)

Infectious bovine keratoconjunctivitis: contact transmission.

The transmission of Moraxella bovis was studied in calves in the absence of the face fly (Musca autumnalis) or environmental conditions that might insult the eye. Thirty calves were placed in 10 groups of 1 experimentally infected calf and 2 contact calves each. Over 40 days, only 1 eye in 1 contact calf developed clinical infectious bovine keratoconjunctivitis. The organism was recovered in only 8 of 20 contact calves, whereas infection and disease occurred in all experimentally infected calves. Transmission of M bovis occurring in the absence of some other intervening factor was probably of minimal importance. Seemingly, herd preventive treatment would be most effective when flies and environmental factors are at a minimum.