Coenurosis of Yak, Bos grunniens, caused by Taenia multiceps: A Case Report with Molecular Identification in Qinghai Tibetan Plateau Area, China

Coenurosis is an important zoonotic helminthic disease caused by the larval stage of the tapeworm Taenia multiceps. This parasite typically infects the brain of the intermediate hosts, including sheep, goat, cattle and even humans. We report a case of T. multiceps infection in a yak confirmed by clinical symptoms, morphological characteristics, and molecular and phylogenetic analyses. The coenurus was thin-walled, whitish, and spherical in shape with a diameter of 10 cm. The parasite species was identified as T. multiceps by PCR amplification and sequencing of the 18S rRNA, cox1 and nad1 genes. Three gene sequences all showed high homology (all above 97%) with the reference sequences from different hosts. Moreover, phylogenetic reconstructions with the 3 published Taenia gene sequences confirmed that the Qinghai yak isolate was closely related to T. multiceps. Although there are advanced diagnosis and treatment methods for coenurosis, early infection is difficult to diagnose. Importantly, the findings of yak infection case should not be ignored due to its zoonotic potential.

Molecular Characterization of Taenia multiceps Isolates from Gansu Province, China by Sequencing of Mitochondrial Cytochrome C Oxidase Subunit 1

A total of 16 Taenia multiceps isolates collected from naturally infected sheep or goats in Gansu Province, China were characterized by sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. The complete cox1 gene was amplified for individual T. multiceps isolates by PCR, ligated to pMD18T vector, and sequenced. Sequence analysis indicated that out of 16 T. multiceps isolates 10 unique cox1 gene sequences of 1,623 bp were obtained with sequence variation of 0.12-0.68%. The results showed that the cox1 gene sequences were highly conserved among the examined T. multiceps isolates. However, they were quite different from those of the other Taenia species. Phylogenetic analysis based on complete cox1 gene sequences revealed that T. multiceps isolates were composed of 3 genotypes and distinguished from the other Taenia species.

Cenurose em ovinos no sul do Brasil: 16 casos / Coenurosis of sheep in southern Brazil: 16 cases

Neste trabalho são descritos casos de doença neurológica causada por Coenurus cerebralis em 16 ovinos provenientes de nove propriedades rurais do Rio Grande do Sul. Os casos ocorreram entre janeiro de 1990 e dezembro de 2006. A evolução clínica variou de 30-90 dias e os ovinos afetados apresentavam depressão (9/16), isolamento do rebanho (8/16), andar cambaleante (7/16), cegueira (4/16), desvio da cabeça (3/16), incoordenação (3/16), movimentos de pedalagem (2/16), quedas (2/16), andar em círculos, deficiência proprioceptiva nos membros torácicos e pélvicos, estrabismo, midríase, opistótono, tremores e rigidez dos membros (1/16 cada). Os achados macroscópicos foram restritos ao sistema nervoso central e caracterizados por cistos de 2 a 9cm de diâmetro preenchidos por líquido translúcido e revestidos por fina membrana. Na parte interna da membrana, havia numerosas estruturas levemente alongadas e brancas de aproximadamente 1mm de diâmetro (escólices). Na maioria dos ovinos, os cistos eram localizados no telencéfalo (12/16); em três, os cistos estavam no cerebelo e em um ovino havia um cisto no cerebelo e um na medula espinhal. Em todos os casos havia acentuada compressão e deslocamento do tecido nervoso adjacente aos cistos. Histologicamente, os cistos parasitários eram formados por dupla membrana fracamente eosinofílica da qual evaginavam múltiplos escólices esféricos acelomados. Adjacente à parede da vesícula eram observadas sucessivas camadas compostas por uma zona de necrose e mineralização, circundadas por infiltrado inflamatório composto por macrófagos epitelióides e células gigantes multinucleadas, com uma cápsula externa de tecido fibrovascular e infiltrado inflamatório linfoistioplasmocitário perivascular. Adicionalmente, havia compressão e atrofia das substâncias branca e cinzenta adjacentes. O diagnóstico de cenurose foi realizado com base nos achados epidemiológicos, clínicos e macroscópicos, e confirmado pela histopatologia.

Sixteen cases of neurologic disease caused by Coenurus cerebralis occurring in sheep from nine farms in Rio Grande do Sul, Brazil, from January 1990 to December 2006, are described. Clinical courses varied from 30 to 90 days and affected sheep developed depression (9/16), isolation from the herd (8/16), staggering (7/16), blindness (4/16), head tilt (3/16), incoordination (3/16), paddling (2/16), falls (2/16), circling, proprioceptive deficits in fore and hindlimbs, strabismus, mydriasis, opisthotonus, trembling and rigidity of the limbs (1/16 each one). Macroscopic findings were restricted to central nervous system and consisted of 2 to 9cm fluid filled cysts with numerous slightly elongated 1 mm white scolices attached to the inner wall surface of the capsule. Cysts were located in the telencephalon (12/16); in the cerebellum (3 sheep); and in the cerebellum and spinal cord (1 sheep). All cases showed severe compression and displacement of the adjacent nervous tissue. Histologically, the cyst walls were characterized by a thin walled eosinophilic vesicle in which evaginated multiple spherical acelomated scolices. The cyst wall was surrounded by successive layers consisting of an internal necrotic and mineralized band, a layer of epithelioid macrophages with abundant number of multinucleated giant cell and an external fibrovascular capsule with perivascular lymphohistioplasmacytic infiltrate. Adjacent white and gray matter were compressed and atrophied. The diagnosis was based on epidemiologic, clinical and pathologic findings and confirmed by histopathology.