|An Encephalitozoon cuniculi spore|
From Figure 7 of this paper
Encephalitozoon cuniculi is a type of microsporidian, a single-cell parasite equipped with a structure called a polar tube, which is curled inside the infective spore. Spores are the infectious stage, and are either inhaled or consumed by the host. When it comes into contact with a host cell, the spore discharges its polar tube and penetrates the cell membrane, allowing the parasite to enter. It is an intracellular parasite that lives inside its host's cell, and this species also attacks the host's central nervous system. The most common means of transmission is from the urine of an infected rabbit.
|Dat Shaft head-tilt|
From Figure 1 and 2 of this paper
In Japan, this nasty little parasite has also been found in squirrel monkeys and domestic dogs living in close quarters with humans. The E. cuniculi outbreak at the Japanese facility prompted the study featured in this post, which involved clinical and pathological examinations, and biosecurity countermeasures. The alarm was first raised when two young bunnies showed signs of a central nervous system problems. Blood tests were conducted, and those bunnies were diagnosed with encephalitozoonosis. Following these cases, biosecurity measures were put in place included monitoring, isolation, and transport limitation. Any rabbits even suspected of harbouring E. cuniculi were humanely euthanized. Despite these measures, periodic infections were still occurring, leading to the entire rabbit colony being euthanized. In total, 32 out of the 42 (76.2%) rabbits were found to be infected with E. cuniculi.
Following this incident, the facility was closed and all the equipment, such as cages, feeders, floors were thoroughly sterilized using burners, 70% ethanol solution, and boiled water. New rabbits were introduced back into the facility two months after this procedure. and there has been no recurrence of E. cuniculi outbreaks.
It became clear during this study that the original infection had come from eight rabbits that were introduced to the colony with no quarantine period. Due to the lack of simple biosecurity measures, the act of introducing new bunnies became a death sentence for the whole colony. For this particular facility, the rabbits were a popular interactive attraction for visitors, many of whom were infants or the elderly whose immune systems may not be as strong as others. This highlights the importance of adequate biosecurity and husbandry techniques when dealing with readily transmissible parasites that can be harboured by multiple host species, and can have such devastating effects.
Fukui, D., Bando, G., Furuya, K., Yamaguchi, M., Nakaoka, Y., Kosuge, M., & Murata, K. (2013). Surveillance for an Outbreak of Encephalitozoon cuniculi Infection in Rabbits Housed at a Zoo and Biosecurity Countermeasures. Journal of Veterinary Medical Science, 75(1), 55-61.
This post was written by Brenda Cornick