Environmental Attributes to Respiratory Diseases of Small Ruminants

Abstract

Respiratory diseases are the major disease crisis in small ruminants. A number of pathogenic microorganisms have been implicated in the development of respiratory disease but the importance of environmental factors in the initiation and progress of disease can never be overemphasized. They irritate the respiratory tree producing stress in the microenvironment causing a decline in the immune status of the small ruminants and thereby assisting bacterial, viral, and parasitic infections to break down the tissue defense barriers. Environmental pollutants cause acute or chronic reactions as they deposit on the alveolar surface which are characterized by inflammation or fibrosis and the formation of transitory or persistent tissue manifestation. Some of the effects of exposures may be immediate, whereas others may not be evident for many decades. Although the disease development can be portrayed as three sets of two-way communications (pathogen-environment, host-environment, and host-pathogen), the interactions are highly variable. Moreover, the environmental scenario is never static; new compounds are introduced daily making a precise evaluation of the disease burden almost impossible. The present review presents a detailed overview of these interactions and the ultimate effect on the respiratory health of sheep and goat.

A Survey of Disease Conditions in Sheep and Goats Slaughtered at Coimbatore District Slaughter House, Tamil Nadu, India

“…The details are given in Table 4. More number of lung lesions observed in goats (11.76%) and in sheep (3.65%) in this study this might be due to susceptibility of goats to lower temperatures (Rahal et al, 2014) during winter in this area. There was no significant difference (P>0.05) observed in liver lesions between sheep and goats.…”

Evidence of respiratory syncytial virus and parainfluenza-3 virus in Mexican sheep

“…In the tropic, on the other side, production system is extensive; no other species coexist directly with sheep. While this could explain a lower seroprevalence, the higher relative humidity at the tropic could favor infection by these viruses [28]. This is the first report on RSV and PI3V seroprevalence in lambs and adult sheep in Mexico.…”

“…Predisposing factors for infection by respiratory complex viruses include coexistence with other species like bovines or goats, confinement, constant exposure to pollutants, sudden temperature changes, and stress [3,28,36]. Sheep from the uplands are handled under an intensive-type production system, where they coexist with bovines and goats; overcrowding and the contact between healthy and diseased animals are also favored.…”

Isolation, Identification and Antibiogram of Mannheimia hemolytica Associated with Caprine Pneumonia in the Cauvery Delta Region of Tamil Nadu, India

“…Pathogens like bacteria, virus and parasites have been occupied in the development of respiratory disease along with stress factors. Stress factors such as transport, overcrowding, poor housing conditions and environmental changes cause respiratory insult which result in decline in the immune status of the small ruminants and thereby supporting the number of bacterial, viral, and parasitic diseases to break down the tissue defense barriers (Rahal et al, 2014). Due to loss of natural defense mechanism, goats are highly susceptible to Pasteurella spp.…”