Thumbnail Image

Theses

Browse

20191
Reset filters
Subject: Veterinary Epidemiology and Preventive Medicine × Author: LAHKAR, DEEPA × Start date: 2016 × Type: Thesis × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    NON-CEREBRAL COENUROSIS WITH SPECIAL REFERENCE TO EPDEMIOLOGY AND MOLECULAR CHARACTERIZATION OF Coenurus gaigeri IN GOATS
    (College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, 2019-07) LAHKAR, DEEPA; Das, Bipin Chandra
    An epidemiological investigation was carried out to study the occurrence of noncerebral coenurosis in few goat rearing areas of undivided Kamrup district of Assam during the period from August, 2016 to July, 2018. In the present study, a total of 981 number of goats examined and out of which 53 animals were positive (5.40%), while the occurrence of cerebral coenurosis was recorded only 1.33 per cent. The area wise survey under undivided Kamrup district, revealed highest (7.23%) occurrence of non-cerebral coenurosis in Hajo area while goats from Khanapara area recorded maximum (2.61%) cases of cerebral coenurosis. Non-cerebral coenurosis was significantly (p<0.01) highest (10.27%) among goats of 2-3 years of age as compared to other age groups while none of the cases could be recorded in goats below 6 months of age. Similarly, the occurrence of cerebral coenurosis was also recorded highest in the age group of 2-3 years (2.66%). Sex wise, the occurrence of non-cerebral coenurosis was significantly (p<0.01) higher (8.10%) in female goats as compared to males (1.69%) in the present study. Similarly, a higher percentage of females were also affected with cerebral coenurosis than the male goats. A significantly (<0.01) higher occurrence of non-cerebral coenurosis was recorded in female goats in the age group of 2 to 3 years (14.10%) as compared to males of the same age group. Likewise the occurrence of cerebral coenurosis was also found to be the highest in adult females in the age group of 2 to 3 years than the male goats. Thigh region was found to be the most common site (26.42%) for predilection of non-cerebral coenurus cysts from where maximum number of cysts were recovered which had significantly (p<0.05) higher cyst volume, significantly (p<0.01) larger diameter with significantly (p<0.01) maximum number of protoscolices per coenurus cyst, as compared to other body locations while brain was the common site of predilection for cerebral coenurus cysts in goats. Both non-cerebral and cerebral coenurus cysts found in the present study was characterized by a thin transparent wall filled with a transluscent fluid of varying volume with presence of numerous invaginated protoscolices, were arranged in clusters and found to attach to the germinal membrane of the cyst wall. However, non-cerebral cyst was additionally enclosed by an outer fibrous connective tissue capsule. Based on the keys and guidelines of Soulsby (1982), the coenurus cysts recovered from the subcutaneous and muscle tissues of goats and from brain in the present study, were tentatively identified as Coenurus gaigeri and Coenurus cerebralis, respectively. The mean (± SE) prepatent period of adult taeniids following experimental infection of dogs with non-cerebral and cerebral coenurus cysts from goats, was found to be 60.20 ± 1.06 days (ranging between 57 to 63 days) and 56.80 ± 1.91 days (52 to 61 days), respectively. Dogs infected with non-cerebral coenurus cyst resulted in development of adult taeniids in the jejunum of small intestine from where, 32 numbers of parasites were recovered with intact scolex with evidence of hyperaemia on the mucosa. Similarly, dogs infected with cerebral cysts, also showed evidence of adult taeniids in the small intestine particularly in the jejunum and ileum. The adult taeniids of dogs derived from both noncerebral and cerebral origin, were whitish in colour, and measured 70 to 85 cm and 45 to 62 cm in length, respectively. The number of segments per worm from non-cerebral and cerebral origin was ranging from 61 to 102 numbers and 45 to 73 numbers respectively. The scolex of taeniid parasites derived from non-cerebral and cerebral origin was found to be globular in shape with four cup shaped suckers along with a prominent rostellum with double rows of rostellar hooks. The length of the large hooks in taeniids derived from cerebral origin was significantly (p<0.05) higher as compared to the large hooks of taeniids derived from non-cerebral origin. Similarly, the length of the blade of large rostellar hooks of taeniids from cerebral origin was also significantly (p<0.05) higher as compared to the blade length of taeniids from non-cerebral origin. The PCR reaction targeting amplification CO1 and NAD1 gene of Taenia multiceps yielded the expected 444 bp and 530 bp products in the present study. The pair wise alignment of both the mitochondrial CO1 gene (CC_CO1, NC_CO1) sequences of cerebral and non-cerebral cysts showed a similarity of 98-99% and 99-100%, respectively. The phylogenetic analysis based on CO1 gene sequences revealed that the present isolates (CC_CO1 and NC_CO1) were closely related to an isolate of Taenia multiceps reported from China (Accession No. KX 547641.1) and showed 99.76% and 100% similarity, respectively which they formed a single clad and thereby confirmed that both the isolates belonged to Taenia multiceps. The NAD1 gene (CC_NAD1, NC_NAD1) sequences of both type of cysts also showed similarity of 97-99% and 98-99%, respectively to the identical sequences of Taenia multiceps in the GeneBank database and confirmed the identity of the query sequence to be Taenia multiceps. The phylogenetic analysis of NAD1 sequences revealed that the present isolate CC_NAD1 was closely related with a Greece isolate (Acc. No. KR 604804.1), an Iranian isolate and two isolates from Turkey showing 99.22, 98.92, 98.60 and 98.00% similarity, with which it formed a single clad and thereby confirmed the present isolate to be of Taenia multiceps. The other isolate, NC_NAD1, although showed 99.59% similarity with an isolate of T. multiceps from Greece (KR 604804.1) but it formed a separate clad within the same cluster in the phylogenetic tree. Based on the phylogenetic analysis of CO1 and NAD1 gene sequences, it can be concluded that Taenia multiceps is the single valid species and the origin of both non-cerebral (Coenurus gaigeri) and cerebral (Coenurus cerebralis) coenurus cysts in goats in the present study. The molecular data based on CO1 and NAD1 sequences of both non-cerebral and cerebral coenurus cysts in goats was reported for the first time from Assam, India.