THE TRANSMISSION AND TREATMENT OF INFECTIOUS OPHTHALMIA OF CATTLE

Area of Science:

• Veterinary Ophthalmology
• Bacteriology
• Infectious Disease Transmission

Background:

• Flies are observed feeding on ocular exudates, suggesting a potential role in disease transmission.
• Previous assumptions about fly transmission are challenged by experimental findings.

Purpose of the Study:

• To investigate the viability of the bacterium on flies and its role in disease transmission.
• To understand the persistence of the organism in the eye and nasal passages.
• To identify transmission routes and seasonal patterns of the disease.

Main Methods:

• Experiments involving attempted disease transmission by flies.
• Observation of bacterial viability on external fly surfaces and in the digestive tract.
• Examination of bacterial presence in ocular and nasal secretions.
• Experimental inoculation of the cornea with bacterial cultures.
• Assessment of treatment efficacy with zinc sulfate.

Main Results:

• The bacterium remains viable for only a few minutes in the fly's digestive tract and less than 3 hours on its external surfaces.
• The organism can persist on the eye after acute symptoms subside, facilitating transmission.
• The bacterium was detected in nasal passages during the incubation and early stages of infection.
• Experimental inoculation on the cornea successfully induced the disease.
• Ocular inflammation resolved effectively with 1:40 zinc sulfate treatment.

Conclusions:

• Flies are unlikely to be the primary vector due to rapid bacterial death.
• The eye serves as a reservoir for the bacterium, explaining seasonal outbreaks.
• Nasal secretions, particularly during early infection, may contribute to sporadic cases.
• Direct inoculation onto the cornea is an effective route of infection.
• Zinc sulfate is an effective treatment for the ocular inflammation.