Characterization of serum lysosomal enzymatic activities. III. Effect of infectious influenza in Egyptian equines.

The research article is about a study that examined the impact of an outbreak of infectious influenza on specific enzymes in several equines in Egypt, and the subsequent therapeutic use of antibiotics.

Study Introduction and Context

• The study was triggered by an outbreak of infectious influenza in Menofeia, Egypt in October 1989.
• Eight equines – horses, mules, and donkeys – that were naturally infected in this outbreak, and 8 healthy control animals, were selected as subjects of this study. The primary aim was to examine the impact of the influenza infection on four different lysosomal enzymatic activities in these animals.

Clinical Observations

• The researchers documented several clinical observations in the infected equines. Common symptoms included fever, nasal congestion, conjunctival membranes, and cough. Some animals also developed bronchopneumonia with bilateral purulent nasal discharge, which was seen in two donkeys.
• The conditions worsened over time, leading to labored breathing in several equines. In response, a dose of penicillin-streptomycin was administered to protect against secondary bacterial infection.

Lysosomal Enzyme Levels

• The next phase of the study involved the estimation of four lysosomal enzymatic activities in the blood serum of the animals. Lysosomal enzymes break down waste materials and cellular debris and can be excellent indicators of the overall health and physiology of an organism.
• Most of these enzymes showed a consistent regression, indicating a reduction in their activities, apart from N-acetyl-beta-glucosaminidase (beta-NAG). The activity of beta-NAG was found to be very significantly higher, which the researchers suggest it likely due to the acidic pH conditions created by bronchopneumonia and respiratory acidosis. The acidity of the conditions seemed to override the inhibitory action of the antibiotics administered.

Impact of Influenza Virus and Antibiotics

• The influenza virus may inhibit the synthesis of pulmonary surfactant in the alveolar and bronchial epithelium, causing respiratory distress and bronchospasm in the animals.
• This decreased the value of acid phosphatase (ACP), an enzyme that was histochemically located at both sites.
• Furthermore, the administration of antibiotics seemed to lead to the disappearance of alpha- and beta-galactosidases (alpha-GAL & beta-GAL) from the serum of the ill animals.

Conclusions

• This research provides insightful observations into the lysosomal enzymatic activities changes in response to influenza infection in equines. It sheds light on a probable mechanism for the observed enzyme changes related to the action of the influenza virus and antibiotics.
• However, the specific interplay of the virus, antibiotics and lysosomal enzymatic activities is complex and may require further investigation.