Cerebral Coenurosis in Small Ruminants: A Review

Abstract

Cerebral coenurosis is an important disease affecting sheep and goat which causes significant economic losses in their production. Cerebral Coenurosis is caused by larval stage of taenia multiceps known as coenurus cerebralis. The aim of this paper is to review the general aspects of cerebral coenurosis in small ruminants' and highlight its economic and public health significance. Coenurosis occurs in worldwide and it is endemic in Ethiopia, especially in the highland area where sheep population is high. The life cycle is commonly happens between dog and small ruminants. The adult stage of this parasite inhabits the small intestine of dogs, foxes, coyotes and jackals; while larvae are found in the brain and spinal cord of intermediate hosts. When dog consume the brain containing coenurus cyst, cyst develop into taenia multiceps and then start to pass proglottid containing egg on pasture and intermediate hosts get infected when ingest eggs from pasture. Circling, Dullness, torticollis, loss of appetite, frequent bleating, separation from the flock, visual impairment, muscle tremors are the main clinical signs related with coenurusis. Diagnosis is mostly by necrosy while radiology, ultrasonography and CT can also be used. Treatment of choice is by surgical removal of the cyst or by aspiration of fluid from the cyst; also combination of Fenbendazole, praziquantel and albendazole is effective against migratory stage of the larvae. The disease causes great economic loss in small ruminant production. Human get infected with coenurosis if ingests an egg of the parasite accidentally. Regular anthelmintic treatment of dogs, correct disposal of sheep and goat brain are the main control method of coenurosis. The community should Control dog contact with pasture and have to properly dispose the brain of infected sheep and goats after slaughter; also they should keep their hygiene to prevent ingestion of T. multiceps eggs.

Are current practices of yak herdsmen adequate to combat Coenurosis in Laya Bhutan?

“…The tradition of dog keeping F I G U R E 3 Common causes of yak mortality in Laya subdistrict F I G U R E 4 Seasonal occurrence of Gid and number of yaks lost to Gid may have been useful but it has contributed to spreading gid, which threatens the livelihoods of yak herders. Similar incidence has been reported in the sheep-rearing areas, where the presence of shepherd dogs on grazing land and paddocks, greatly contributed to the existence of Coenurosis (Abera et al, 2016).…”

“…Affected yaks could likely have died in spring, as reported by Gyamtsho (2000) that gid leads to death in spring when yaks are very weak due to severe forage scarcity. The cyst of T. multiceps has been reported to mature in approximately 8 months when infected yak shows nervous symptoms (Abera et al, 2016). Therefore, the maximum occurrence of gid in winter (Figure 4) suggests that yaks are infected in summer while grazing on pastures contaminated with eggs of T. multiceps.…”

First report of an outbreak of cerebral coenurosis in Dhofari goats in Oman

“…Infection spread seems to be ecology-dependent, aggravated by rainfall, high moisture, and moderate temperature of the altitudes, which keep the parasitic eggs viable for longer periods and facilitates their dispersion over distant regions (ABERA et al, 2016;SCALA & VARCASIA, 2006). Salalah region has humid weather from June to September (KWARTENG et al, 2009).…”

“…Clinical cerebral coenurosis occurs in small ruminants and sheep are mostly susceptible (ABERA et al, 2016;SHARMA & CHAUHAN, 2006). In the present study, the problem was investigated in a goat farm.…”

“…Clinically, cerebral coenurosis is reported in either acute or chronic form. The acute form occurs due to intense larval migration in the central nervous system (CNS) following the exposure to massive parasitic infestation, while the chronic form is frequently recorded as bladder cysts development in the CNS (ABERA et al, 2016;ORYAN et al, 2014). Chronic cerebral coenurosis is more common than the acute form, and both forms are fatal (ALEMU et al, 2015).…”